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  1. Multi-scale, multi-method geophysical investigations of the Valles Caldera

    Science.gov (United States)

    Barker, J. E.; Daneshvar, S.; Langhans, A.; Okorie, C.; Parapuzha, A.; Perez, N.; Turner, A.; Smith, E.; Carchedi, C. J. W.; Creighton, A.; Folsom, M.; Bedrosian, P.; Pellerin, L.; Feucht, D. W.; Kelly, S.; Ferguson, J. F.; McPhee, D.

    2017-12-01

    In 2016, the Summer of Applied Geophysical Experience (SAGE) program, in cooperation with the National Park Service, began a multi-year investigation into the structure and evolution of the Valles Caldera in northern New Mexico. The Valles Caldera is a 20-km wide topographic depression in the Jemez Mountains volcanic complex that formed during two massive ignimbrite eruptions at 1.65 and 1.26 Ma. Post-collapse volcanic activity in the caldera includes the rise of Redondo peak, a 1 km high resurgent dome, periodic eruptions of the Valles rhyolite along an inferred ring fracture zone, and the presence of a geothermal reservoir beneath the western caldera with temperatures in excess of 300°C at a mere 2 km depth. Broad sediment-filled valleys associated with lava-dammed Pleistocene lakes occupy much of the northern and southeastern caldera. SAGE activities to date have included collection of new gravity data (>120 stations) throughout the caldera, a transient electromagnetic (TEM) survey of Valle Grande, reprocessing of industrial magnetotelluric (MT) data collected in the 1980s, and new MT data collection both within and outside of the caldera. Gravity modeling provides constraints on the pre-Caldera structure, estimates of the thickness of Caldera fill, and reveals regional structural trends reflected in the geometry of post-Caldera collapse. At a more local scale, TEM-derived resistivity models image rhyolite flows radiating outward from nearby vents into the lacustrine sediments filling Valle Grande. Resistivity models along a 6-km long profile also provide hints of structural dismemberment along the inferred Valles and Toledo ring fracture zones. Preliminary MT modeling at the caldera scale reveals conductive caldera fill, the resistive crystalline basement, and an enigmatic mid-crustal conductor likely related to magmatic activity that post-dates caldera formation.

  2. Chapter 1. Valles Caldera National Preserve land use history

    Science.gov (United States)

    Kurt F. Anschuetz

    2007-01-01

    The land use history of the Valles Caldera National Preserve (VCNP) extends back over thousands of years. Few known archaeological properties in the Valles Caldera date to the Paleoindian period (10000/9500–5500 B.C.). These finds include the recent discovery, during ongoing archaeological studies (Dr. Bob Parmeter, personal communication, VCNP, Los Alamos, 2005), of...

  3. Caldera processes and magma-hydrothermal systems continental scientific drilling program: thermal regimes, Valles caldera research, scientific and management plan

    Energy Technology Data Exchange (ETDEWEB)

    Goff, F.; Nielson, D.L. (eds.)

    1986-05-01

    Long-range core-drilling operations and initial scientific investigations are described for four sites in the Valles caldera, New Mexico. The plan concentrates on the period 1986 to 1993 and has six primary objectives: (1) study the origin, evolution, physical/chemical dynamics of the vapor-dominated portion of the Valles geothermal system; (2) investigate the characteristics of caldera fill and mechanisms of caldera collapse and resurgence; (3) determine the physical/chemical conditions in the heat transfer zone between crystallizing plutons and the hydrothermal system; (4) study the mechanism of ore deposition in the caldera environment; (5) develop and test high-temperature drilling techniques and logging tools; and (6) evaluate the geothermal resource within a large silicic caldera. Core holes VC-2a (500 m) and VC-2b (2000 m) are planned in the Sulphur Springs area; these core holes will probe the vapor-dominated zone, the underlying hot-water-dominated zone, the boiling interface and probable ore deposition between the two zones, and the deep structure and stratigraphy along the western part of the Valles caldera fracture zone and resurgent dome. Core hole VC-3 will involve reopening existing well Baca number12 and deepening it from 3.2 km (present total depth) to 5.5 km, this core hole will penetrate the deep-crystallized silicic pluton, investigate conductive heat transfer in that zone, and study the evolution of the central resurgent dome. Core hole VC-4 is designed to penetrate deep into the presumably thick caldera fill in eastern Valles caldera and examine the relationship between caldera formation, sedimentation, tectonics, and volcanism. Core hole VC-5 is to test structure, stratigraphy, and magmatic evolution of pre-Valles caldera rocks, their relations to Valles caldera, and the influences of regional structure on volcanism and caldera formation.

  4. Cooling history of the Valles Caldera, New Mexico using ESR dating method

    International Nuclear Information System (INIS)

    Ogoh, K.; Toyoda, S.; Ikeda, S.; Ikeya, M.; Goff, F.

    1993-01-01

    ESR dating was made at the Valles caldera by using the Al center and Ti center in quartz grains separated from the layers of the Valles Rhyolite. Obtained ESR ages were much younger than those by other methods (fission track and 39 Ar- 40 Ar). A reported thermal event of about 10-40 ka ago might explain the difference between the above ages. (author)

  5. Applying hydrology to land management on the Valles Caldera National Preserve

    Science.gov (United States)

    Robert R. Parmenter

    2009-01-01

    Since 2004, the Valles Caldera National Preserve (VCNP) in the Jemez Mountains of northern New Mexico has hosted extensive field hydrology research by scientists from the Center for Sustainability of semi- Arid Hydrology and Riparian Areas (SAHRA) at the University of Arizona. With the development of a detailed hydrologic understanding of VCNP's climate, geology,...

  6. Perspectives on managing multi-cultural landscapes: Use, access, and fire/fuels management attitudes and preferences of user groups concerning the Valles Caldera National Preserve (VCNP) and adjacent areas

    Science.gov (United States)

    Kurt F. Anschuetz

    2014-01-01

    The Valles Caldera National Preserve (VCNP), which consists of a large, 1.2- to 1.6-million-year-old volcanic caldera, forms the heart of the Jemez Mountains in north-central New Mexico (Figure 1). Known as the Valles Caldera, this bowl-shaped hollow is an especially treasured place within this beloved mountainous landscape for many residents of the region. Its valles...

  7. New Seismic Monitoring Station at Mohawk Ridge, Valles Caldera

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Peter Morse [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-09-20

    Two new broadband digital seismic stations were installed in the Valles Caldera in 2011 and 2012. The first is located on the summit of Cerros del Abrigo (station code CDAB) and the second is located on the flanks of San Antonio Mountain (station code SAMT). Seismic monitoring stations in the caldera serve multiple purposes. These stations augment and expand the current coverage of the Los Alamos Seismic Network (LASN), which is operated to support seismic and volcanic hazards studies for LANL and northern New Mexico (Figure 1). They also provide unique continuous seismic data within the caldera that can be used for scientific studies of the caldera’s substructure and detection of very small seismic signals that may indicate changes in the current and evolving state of remnant magma that is known to exist beneath the caldera. Since the installation of CDAB and SAMT, several very small earthquakes have already been detected near San Antonio Mountain just west of SAMT (Figure 2). These are the first events to be seen in that area. Caldera stations also improve the detection and epicenter determination quality for larger local earthquakes on the Pajarito Fault System east of the Preserve and the Nacimiento Uplift to the west. These larger earthquakes are a concern to LANL Seismic Hazards assessments and seismic monitoring of the Los Alamos region, including the VCNP, is a DOE requirement. Currently the next closest seismic stations to the caldera are on Pipeline Road (PPR) just west of Los Alamos, and Peralta Ridge (PER) south of the caldera. There is no station coverage near the resurgent dome, Redondo Peak, in the center of the caldera. Filling this “hole” is the highest priority for the next new LASN station. We propose to install this station in 2018 on Mohawk Ridge just east of Redondito, in the same area already occupied by other scientific installations, such as the MCON flux tower operated by UNM.

  8. Chapter 9. The Valles Caldera National Preserve as a multi-layered ethnographic landscape

    Science.gov (United States)

    Kurt F. Anschuetz

    2007-01-01

    The land use history of the Valles Caldera National Preserve (VCNP), as represented in the documentary record maintained in various archives and libraries, focuses primarily on the Hispanic and Anglo-American occupation of the locale subsequent to 1860. In an act of June 21, 1860, the U.S. Congress authorized the Baca Land Grant heirs to choose as many as five square...

  9. Geothermal hydrology of Valles Caldera and the southwestern Jemez Mountains, New Mexico

    Science.gov (United States)

    Trainer, Frank W.; Rogers, Robert J.; Sorey, M.L.

    2000-01-01

    The Jemez Mountains in north-central New Mexico are volcanic in origin and have a large central caldera known as Valles Caldera. The mountains contain the Valles geothermal system, which was investigated during 1970-82 as a source of geothermal energy. This report describes the geothermal hydrology of the Jemez Mountains and presents results of an earlier 1972-75 U.S. Geological Survey study of the area in light of more recent information. Several distinct types of thermal and nonthermal ground water are recognized in the Jemez Mountains. Two types of near-surface thermal water are in the caldera: thermal meteoric water and acid sulfate water. The principal reservoir of geothermal fluids is at depth under the central and western parts of the caldera. Nonthermal ground water in Valles Caldera occurs in diverse perched aquifers and deeper valley-fill aquifers. The geothermal reservoir is recharged by meteorically derived water that moves downward from the aquifers in the caldera fill to depths of 6,500 feet or more and at temperatures reaching about 330 degrees Celsius. The heated geothermal water rises convectively to depths of 2,000 feet or less and mixes with other ground water as it flows away from the geothermal reservoir. A vapor zone containing steam, carbon dioxide, and other gases exists above parts of the liquid-dominated geothermal zone. Two subsystems are generally recognized within the larger geothermal system: the Redondo Creek subsystem and the Sulphur Creek subsystem. The permeability in the Redondo Creek subsystem is controlled by stratigraphy and fault-related structures. Most of the permeability is in the high-angle, normal faults and associated fractures that form the Redondo Creek Graben. Faults and related fractures control the flow of thermal fluids in the subsystem, which is bounded by high-angle faults. The Redondo Creek subsystem has been more extensively studied than other parts of the system. The Sulphur Springs subsystem is not as well

  10. Public views and attitudes concerning fire and fuels reduction strategies in the Valles Caldera National Preserve (VCNP) New Mexico

    Science.gov (United States)

    Kurt Anschuetz; Carol Raish

    2010-01-01

    The Valles Caldera National Preserve (VCNP), located in the heart of the Jemez Mountains in northcentral New Mexico, is a special place for many residents of the region. The large volcanic caldera, formerly the privately owned Baca Ranch, is an 89,000-acre property known for its scenic meadows and abundant wildlife, including herds of elk. The U.S. purchased the...

  11. Modeling Pre- and Post- Wildfire Hydrologic Response to Vegetation Change in the Valles Caldera National Preserve, NM

    Science.gov (United States)

    Gregory, A. E.; Benedict, K. K.; Zhang, S.; Savickas, J.

    2017-12-01

    Large scale, high severity wildfires in forests have become increasingly prevalent in the western United States due to fire exclusion. Although past work has focused on the immediate consequences of wildfire (ie. runoff magnitude and debris flow), little has been done to understand the post wildfire hydrologic consequences of vegetation regrowth. Furthermore, vegetation is often characterized by static parameterizations within hydrological models. In order to understand the temporal relationship between hydrologic processes and revegetation, we modularized and partially automated the hydrologic modeling process to increase connectivity between remotely sensed data, the Virtual Watershed Platform (a data management resource, called the VWP), input meteorological data, and the Precipitation-Runoff Modeling System (PRMS). This process was used to run simulations in the Valles Caldera of NM, an area impacted by the 2011 Las Conchas Fire, in PRMS before and after the Las Conchas to evaluate hydrologic process changes. The modeling environment addressed some of the existing challenges faced by hydrological modelers. At present, modelers are somewhat limited in their ability to push the boundaries of hydrologic understanding. Specific issues faced by modelers include limited computational resources to model processes at large spatial and temporal scales, data storage capacity and accessibility from the modeling platform, computational and time contraints for experimental modeling, and the skills to integrate modeling software in ways that have not been explored. By taking an interdisciplinary approach, we were able to address some of these challenges by leveraging the skills of hydrologic, data, and computer scientists; and the technical capabilities provided by a combination of on-demand/high-performance computing, distributed data, and cloud services. The hydrologic modeling process was modularized to include options for distributing meteorological data, parameter space

  12. Estimating Catchment-Scale Snowpack Variability in Complex Forested Terrain, Valles Caldera National Preserve, NM

    Science.gov (United States)

    Harpold, A. A.; Brooks, P. D.; Biederman, J. A.; Swetnam, T.

    2011-12-01

    Difficulty estimating snowpack variability across complex forested terrain currently hinders the prediction of water resources in the semi-arid Southwestern U.S. Catchment-scale estimates of snowpack variability are necessary for addressing ecological, hydrological, and water resources issues, but are often interpolated from a small number of point-scale observations. In this study, we used LiDAR-derived distributed datasets to investigate how elevation, aspect, topography, and vegetation interact to control catchment-scale snowpack variability. The study area is the Redondo massif in the Valles Caldera National Preserve, NM, a resurgent dome that varies from 2500 to 3430 m and drains from all aspects. Mean LiDAR-derived snow depths from four catchments (2.2 to 3.4 km^2) draining different aspects of the Redondo massif varied by 30%, despite similar mean elevations and mixed conifer forest cover. To better quantify this variability in snow depths we performed a multiple linear regression (MLR) at a 7.3 by 7.3 km study area (5 x 106 snow depth measurements) comprising the four catchments. The MLR showed that elevation explained 45% of the variability in snow depths across the study area, aspect explained 18% (dominated by N-S aspect), and vegetation 2% (canopy density and height). This linear relationship was not transferable to the catchment-scale however, where additional MLR analyses showed the influence of aspect and elevation differed between the catchments. The strong influence of North-South aspect in most catchments indicated that the solar radiation is an important control on snow depth variability. To explore the role of solar radiation, a model was used to generate winter solar forcing index (SFI) values based on the local and remote topography. The SFI was able to explain a large amount of snow depth variability in areas with similar elevation and aspect. Finally, the SFI was modified to include the effects of shading from vegetation (in and out of

  13. Electrical Resistivity Structure of the Valles Caldera, New Mexico, USA: Results From 3D Inversion of Modern and Legacy Magnetotelluric Data Collected by Industry and the Summer of Applied Geophysical Experience (SAGE).

    Science.gov (United States)

    Feucht, D. W.; Bedrosian, P.; Jiracek, G. R.; Pellerin, L.; Nettleton, C. E.

    2017-12-01

    The Valles caldera, in north-central New Mexico, USA, is a 20-km wide topographic depression in the Jemez Mountains volcanic complex that formed during two massive ignimbrite eruptions 1.65 and 1.26 Ma. Post-collapse volcanic activity in the caldera includes the rise of a 1 km high resurgent dome, periodic eruptions of the Valles rhyolite along ring fractures, and the presence of a geothermal reservoir beneath the western caldera with temperatures in excess of 300°C at a mere 2 km depth. We present an electrical resistivity model of the upper crust from three-dimensional (3D) inversion of broadband (100 Hz to 600 s) magnetotelluric (MT) data collected in and around the Valles caldera. The Summer of Applied Geophysical Experience (SAGE) has been acquiring geophysical data in the northern Rio Grande rift for more than three decades (1983-2017). Included in that vast dataset are over 60 broadband magnetotelluric soundings that have recently been cataloged, geo-located, and digitized for use in modern geophysical processing and modeling. The resistivity models presented here were produced by inverting a subset of SAGE MT data along with 30 broadband MT soundings acquired by the Unocal Corporation in 1983 for geothermal exploration of the caldera. We use the 3D inversion algorithm ModEM (Egbert and Kelbert, 2012) to invert full impedance tensors and tipper functions from >30 MT stations for the electrical resistivity structure beneath the caldera. Our preferred model reveals the geometry and electrical properties of (1) the conductive caldera fill, (2) the resistive crystalline basement, and (3) an enigmatic mid-crustal conductor related to magmatic activity that post-dates caldera formation.

  14. Zeolitization of intracaldera sediments and rhyolitic rocks in the 1.25 Ma lake of Valles caldera, New Mexico, USA

    Science.gov (United States)

    Chipera, Steve J.; Goff, Fraser; Goff, Cathy J.; Fittipaldo, Melissa

    2008-12-01

    Quantitative X-ray diffraction analysis of about 80 rhyolite and associated lacustrine rocks has characterized previously unrecognized zeolitic alteration throughout the Valles caldera resurgent dome. The alteration assemblage consists primarily of smectite-clinoptilolite-mordenite-silica, which replaces groundmass and fills voids, especially in the tuffs and lacustrine rocks. Original rock textures are routinely preserved. Mineralization typically extends to depths of only a few tens of meters and resembles shallow "caldera-type zeolitization" as defined by Utada et al. [Utada, M., Shimizu, M., Ito, T., Inoue, A., 1999. Alteration of caldera-forming rocks related to the Sanzugawa volcanotectonic depression, northeast Honshu, Japan — with special reference to "caldera-type zeolitization." Resource Geol. Spec. Issue No. 20, 129-140]. Geology and 40Ar/ 39Ar dates limit the period of extensive zeolite growth to roughly the first 30 kyr after the current caldera formed (ca. 1.25 to 1.22 Ma). Zeolitic alteration was promoted by saturation of shallow rocks with alkaline lake water (a mixture of meteoric waters and degassed hydrothermal fluids) and by high thermal gradients caused by cooling of the underlying magma body and earliest post-caldera rhyolite eruptions. Zeolitic alteration of this type is not found in the later volcanic and lacustrine rocks of the caldera moat (≤ 0.8 Ma) suggesting that later lake waters were cooler and less alkaline. The shallow zeolitic alteration does not have characteristics resembling classic, alkaline lake zeolite deposits (no analcime, erionite, or chabazite) nor does it contain zeolites common in high-temperature hydrothermal systems (laumontite or wairakite). Although aerially extensive, the early zeolitic alteration does not form laterally continuous beds and are consequently, not of economic significance.

  15. Progress Report Phase I: Use, access, and fire/fuels management attitudes and preferences of user groups concerning the Valles Caldera National Preserve (VCNP) and adjacent areas

    Science.gov (United States)

    Kurt F. Anschuetz; Carol B. Raish

    2010-01-01

    This document represents a progress report of activities completed during Phase I of the study titled, Use, Access, and Fire/Fuels Management Attitudes and Preferences of User Groups Concerning the Valles Caldera National Preserve (VCNP) and Adjacent Areas, and the preliminary findings of this work.

  16. Isotopic and trace element characteristics of rhyolites from the Valles Caldera, New Mexico. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Self, S.; Sykes, M.L. [Hawaii Univ., Honolulu, HI (United States). Dept. of Geology and Geophysics; Wolff, J.A. [Texas Univ., Arlington, TX (United States). Dept. of Geology; Skuba, C.E. [McMaster Univ., Hamilton, ON (Canada). Dept. of Geology

    1991-09-01

    This report is a summary of work supported by DOE grant No. DE-FGO5-87ER13795 that was completed or is still in progress. The stated purpose of this grant was to collect geochemical information (trace element, radiogenic isotope and stable oxygen and hydrogen isotope) on samples from core holes VC-I and VC-2a in the Valles caldera in order to establish a consistent detailed intracaldera stratigraphy and relate this to extracaldera volcanic rock units of the Jemez Mountains. Careful stratigraphic control of the intracaldera units is necessary to evaluate models of caldera formation, ignimbrite deposition, and resurgence. Combined stable and radiogenic isotope and trace element data will also provide major insights to petrogenesis of the Bandelier magma system. The composition of non-hydrothermally altered samples from outflow units of the Bandelier Tuff and related volcanics must be known to assess isotopic variations of intracaldera ignimbrite samples. On detailed examination of the VC-2a core samples, it became apparent that hydrothermal alteration is so extensive that no geochemical information useful for stratigraphic fingerprinting or petrogenesis could be obtained, and that correlation with other intracaldera units and extracaldera units must be made on the basis of stratigraphic position and gross lithologic characteristics. Accordingly, we emphasize geochemical data from the extracaldera Bandelier Tuffs and related units which will be useful for comparison with proposed drill hole VC-4 and for any future studies of the region. The stable isotope, radiogenic isotope and trace element data obtained from this project, combined with existing major and trace element data for volcanic rocks from this area, provide an extensive data base essential to future Continental Scientific Drilling Program projects in the Jemez Mountains of New Mexico.

  17. The Valles natural analogue project

    International Nuclear Information System (INIS)

    Stockman, H.; Krumhansl, J.; Ho, C.; McConnell, V.

    1994-12-01

    The contact between an obsidian flow and a steep-walled tuff canyon was examined as an analogue for a highlevel waste repository. The analogue site is located in the Valles Caldera in New Mexico, where a massive obsidian flow filled a paleocanyon in the Battleship Rock tuff. The obsidian flow provided a heat source, analogous to waste panels or an igneous intrusion in a repository, and caused evaporation and migration of water. The tuff and obsidian samples were analyzed for major and trace elements and mineralogy by INAA, XRF, X-ray diffraction; and scanning electron microscopy and electron microprobe. Samples were also analyzed for D/H and 39 Ar/ 4O isotopic composition. Overall,the effects of the heating event seem to have been slight and limited to the tuff nearest the contact. There is some evidence of devitrification and migration of volatiles in the tuff within 10 meters of the contact, but variations in major and trace element chemistry are small and difficult to distinguish from the natural (pre-heating) variability of the rocks

  18. Volcanic Structures Within Niger and Dao Valles, Mars, and Implications for Outflow Channel Evolution and Hellas Basin Rim Development

    Science.gov (United States)

    Korteniemi, J.; Kukkonen, S.

    2018-04-01

    Outflow channel formation on the eastern Hellas rim region is traditionally thought to have been triggered by activity phases of the nearby volcanoes Hadriacus and Tyrrhenus Montes: As a result of volcanic heating subsurface volatiles were mobilized. It is, however, under debate, whether eastern Hellas volcanism was in fact more extensive, and if there were volcanic centers separate from the identified central volcanoes. This work describes previously unrecognized structures in the Niger-Dao Valles outflow channel complex. We interpret them as volcanic edifices: cones, a shield, and a caldera. The structures provide evidence of an additional volcanic center within the valles and indicate volcanic activity both prior to and following the formation of the outflow events. They expand the extent, type, and duration of volcanic activity in the Circum-Hellas Volcanic Province and provide new information on interaction between volcanism and fluvial activity.

  19. Shallow geothermal investigations into the existence of the Valles Caldera outflow plume near Ponderosa and Jemez Pueblo, north-central, New Mexico

    Science.gov (United States)

    Salaz, Robert Ezekiel

    Geothermal research within the Jemez Mountains spans several decades and is documented in many papers. This study serves to extend the research boundary to the south and east outside of Valles caldera and Canon de San Diego, where the main occurrences of geothermal activity are located. The focus of this investigation is to test for a deep ~900 m, stratigraphically-bound thermal aquifer within the Madera Limestone along the western margin of the Santo Domingo basin transition zone near Ponderosa and Jemez Pueblo, in north-central New Mexico. Numerous springs were sampled for aqueous geochemistry to identify leakage of a deeper geothermal aquifer into shallow aquifers. Wells were sampled for temperature anomalies. In addition, two travertine deposits were analyzed for stable isotope composition and one deposit was dated using U-Series techniques to assess the timing and origin of deposition. This study is important because researchers in other extensional basins have identified reasonably good geothermal reservoirs in deep carbonate aquifers that are similar in geologic setting to the Madera Limestone aquifer of this study. The existence of a deep geothermal aquifer near Ponderosa and Jemez Pueblo, New Mexico could prove to be another prospect for geothermal exploration in the Jemez Mountains. Aqueous geochemistry of springs are plotted on ternary Piper diagrams to help classify similar geochemical trends and group these trends into recognizable patterns. These data indicate calcium carbonate rich waters in the north that may gradationally change to alkaline type waters as they flow south through the study area. Contrasting this data, SiO2 and TDS concentrations show two separate systems that may indicate separate confined aquifers. Two distinct TDS regions are observed, one with higher concentrations (>1000 ppm) shows a decrease from N-S and one with lower concentrations (<600 ppm) shows an increase from N-S. The data indicate that the waters can be classified as

  20. New evidence for a magmatic influence on the origin of Valles Marineris, Mars

    Science.gov (United States)

    Dohm, J.M.; Williams, J.-P.; Anderson, R.C.; Ruiz, J.; McGuire, P.C.; Komatsu, G.; Davila, A.F.; Ferris, J.C.; Schulze-Makuch, D.; Baker, V.R.; Boynton, W.V.; Fairen, A.G.; Hare, T.M.; Miyamoto, H.; Tanaka, K.L.; Wheelock, S.J.

    2009-01-01

    In this paper, we show that the complex geological evolution of Valles Marineris, Mars, has been highly influenced by the manifestation of magmatism (e.g., possible plume activity). This is based on a diversity of evidence, reported here, for the central part, Melas Chasma, and nearby regions, including uplift, loss of huge volumes of material, flexure, volcanism, and possible hydrothermal and endogenic-induced outflow channel activity. Observations include: (1) the identification of a new > 50??km-diameter caldera/vent-like feature on the southwest flank of Melas, which is spatially associated with a previously identified center of tectonic activity using Viking data; (2) a prominent topographic rise at the central part of Valles Marineris, which includes Melas Chasma, interpreted to mark an uplift, consistent with faults that are radial and concentric about it; (3) HiRISE-identified landforms along the floor of the southeast part of Melas Chasma that are interpreted to reveal a volcanic field; (4) CRISM identification of sulfate-rich outcrops, which could be indicative of hydrothermal deposits; (5) GRS K/Th signature interpreted as water-magma interactions and/or variations in rock composition; and (6) geophysical evidence that may indicate partial compensation of the canyon and/or higher density intrusives beneath it. Long-term magma, tectonic, and water interactions (Late Noachian into the Amazonian), albeit intermittent, point to an elevated life potential, and thus Valles Marineris is considered a prime target for future life detection missions. ?? 2008 Elsevier B.V.

  1. Calderas and mineralization: volcanic geology and mineralization in the Chianti caldera complex, Trans-Pecos Texas

    Energy Technology Data Exchange (ETDEWEB)

    Duex, T.W.; Henry, C.D.

    1981-01-01

    This report describes preliminary results of an ongoing study of the volcanic stratigraphy, caldera activity, and known and potential mineralization of the Chinati Mountains area of Trans-Pecos Texas. Many ore deposits are spatially associated with calderas and other volcanic centers. A genetic relationship between calderas and base and precious metal mineralization has been proposed by some and denied by others. Steven and others have demonstrated that calderas provide an important setting for mineralization in the San Juan volcanic field of Colorado. Mineralization is not found in all calderas but is apparently restricted to calderas that had complex, postsubsidence igneous activity. A comparison of volcanic setting, volcanic history, caldera evolution, and evidence of mineralization in Trans-Pecos to those of the San Juan volcanic field, a major mineral producer, indicates that Trans-Pecos Texas also could be an important mineralized region. The Chianti caldera complex in Trans-Pecos Texas contains at least two calderas that have had considerable postsubsidence activity and that display large areas of hydrothermal alteration and mineralization. Abundant prospects in Trans-Pecos and numerous producing mines immediately south of the Trans-Pecos volcanic field in Mexico are additional evidence that ore-grade deposits could occur in Texas.

  2. Months between rejuvenation and volcanic eruption at Yellowstone caldera, Wyoming

    Science.gov (United States)

    Till, Christy B.; Vazquez, Jorge A.; Boyce, Jeremy W

    2015-01-01

    Rejuvenation of previously intruded silicic magma is an important process leading to effusive rhyolite, which is the most common product of volcanism at calderas with protracted histories of eruption and unrest such as Yellowstone, Long Valley, and Valles, USA. Although orders of magnitude smaller in volume than rare caldera-forming super-eruptions, these relatively frequent effusions of rhyolite are comparable to the largest eruptions of the 20th century and pose a considerable volcanic hazard. However, the physical pathway from rejuvenation to eruption of silicic magma is unclear particularly because the time between reheating of a subvolcanic intrusion and eruption is poorly quantified. This study uses geospeedometry of trace element profiles with nanometer resolution in sanidine crystals to reveal that Yellowstone’s most recent volcanic cycle began when remobilization of a near- or sub-solidus silicic magma occurred less than 10 months prior to eruption, following a 220,000 year period of volcanic repose. Our results reveal a geologically rapid timescale for rejuvenation and effusion of ~3 km3 of high-silica rhyolite lava even after protracted cooling of the subvolcanic system, which is consistent with recent physical modeling that predict a timescale of several years or less. Future renewal of rhyolitic volcanism at Yellowstone is likely to require an energetic intrusion of mafic or silicic magma into the shallow subvolcanic reservoir and could rapidly generate an eruptible rhyolite on timescales similar to those documented here.

  3. PREFACE: Collapse Calderas Workshop

    Science.gov (United States)

    Gottsmann, Jo; Aguirre-Diaz, Gerardo

    2008-10-01

    Caldera-formation is one of the most awe-inspiring and powerful displays of nature's force. Resultant deposits may cover vast areas and significantly alter the immediate topography. Post-collapse activity may include resurgence, unrest, intra-caldera volcanism and potentially the start of a new magmatic cycle, perhaps eventually leading to renewed collapse. Since volcanoes and their eruptions are the surface manifestation of magmatic processes, calderas provide key insights into the generation and evolution of large-volume silicic magma bodies in the Earth's crust. Despite their potentially ferocious nature, calderas play a crucial role in modern society's life. Collapse calderas host essential economic deposits and supply power for many via the exploitation of geothermal reservoirs, and thus receive considerable scientific, economic and industrial attention. Calderas also attract millions of visitors world-wide with their spectacular scenic displays. To build on the outcomes of the 2005 calderas workshop in Tenerife (Spain) and to assess the most recent advances on caldera research, a follow-up meeting was proposed to be held in Mexico in 2008. This abstract volume presents contributions to the 2nd Calderas Workshop held at Hotel Misión La Muralla, Querétaro, Mexico, 19-25 October 2008. The title of the workshop `Reconstructing the evolution of collapse calderas: Magma storage, mobilisation and eruption' set the theme for five days of presentations and discussions, both at the venue as well as during visits to the surrounding calderas of Amealco, Amazcala and Huichapan. The multi-disciplinary workshop was attended by more than 40 scientist from North, Central and South America, Europe, Australia and Asia. Contributions covered five thematic topics: geology, geochemistry/petrology, structural analysis/modelling, geophysics, and hazards. The workshop was generously supported by the International Association of Volcanology and the Chemistry of The Earth's Interior

  4. Types of collapse calderas

    Energy Technology Data Exchange (ETDEWEB)

    Aguirre-Diaz, Gerardo J [Centro de Geociencias, Universidad Nacional Autonoma de Mexico, Campus Juriquilla, Queretaro, Qro., 76230 (Mexico)], E-mail: ger@geociencias.unam.mx

    2008-10-01

    Three main types of collapse calderas can be defined, 1) summit caldera: those formed at the top of large volcanoes, 2) classic caldera: semi-circular to irregular-shaped large structures, several km in diameter and related to relatively large-volume pyroclastic products, and 3) graben caldera: explosive volcano-tectonic collapse structures from which large-volume, ignimbrite-forming eruptions occurred through several fissural vents along the graben master faults and the intra-graben block faults. These in turn can collapse at least with three styles: 1) Piston: when the collapse occurs as a single crustal block; 2) Trap-door: when collapse occurs unevenly along one side while the opposite side remains with no collapse; 3) Piece-meal: when collapse occurs as broken pieces of the crust on top of the magma chamber.

  5. Origin of calderas: discriminating between collapses and explosions

    Directory of Open Access Journals (Sweden)

    Izumi Yokoyama

    2017-01-01

    Full Text Available Origins of calderas may differ according to their subsurface structure that may be characterized by high or low density deposits that may be observed as high or low gravity anomalies, respectively. In the Introduction, the pioneering work of Fouqué[1879] on Santorini caldera is referred to in relation to definition of calderas. First, our discussion is focused on four calderas that were seen forming during the period from 1815 (the Tambora eruption to 1991 (the Pinatubo eruption. Coincidently, these four calderas are all low-gravity-anomaly type. Their formation processes and subsurface structure are summarized by the existing data analyzed by various authors. These results are confirmed by results of drillings at some other calderas. Then, caldera formation of both types is discussed: High-gravity-anomaly-type calderas are expected to originate from subsidence of high-density ejecta into the summit magma reservoir. On the calderas of this type, the genetic eruptions believed to be accompanied by subsidences were not actually observed, and consequently three examples are mentioned only briefly. The low-gravity-anomaly-type calderas are discussed from standpoint of both the models of collapses and explosions. It is also emphasized that dynamic pressure ofexplosions is an important factor in the caldera formation, not only volume of the ejecta. To confirm the possibility that volcanic ejecta and edifices collapse into magma reservoirs, we discuss stress propagation from a depleted reservoir upward towards the Earth surface. Formation mechanisms of large calderas of this type are speculated; large calderas measuring about 20 km across may develop by successive merging of component calderas over a long period of times. A Kamchatka caldera under enlargement during the Holocene period is interpreted by successive merging of five component calderas.

  6. How piecemeal is your caldera? Going beyond modelling to investigate the structural evolution of explosive caldera volcanoes

    Energy Technology Data Exchange (ETDEWEB)

    Willcox, Chris; Branney, Mike [University of Leicester, UK, LE1 7RH (United Kingdom); Carrasco-Nunez, Gerardo [Centro de Geociencias Campus Juraquilla, UNAM, Apdo. Postal 1-742 Queretaro, Qro. 76001 (Mexico)], E-mail: cpw14@le.ac.uk

    2008-10-01

    Despite a profusion of analogue models relatively little is known about the internal structure and temporal evolution of explosive caldera volcanoes. So how can modellers test their predictions given that the internal structures of many young calderas are concealed? Mapping ancient exhumed calderas has proven advantageous, yet this requires a large investment of time and expertise to constrain the structural evolution in sufficient detail. We aim to investigate the interplay between the structural evolution and eruption style over time at a modern caldera. We have selected Los Humeros (Mexico) because it is thought to be an example of a caldera with some piecemeal development, and it also has a well-exposed pyroclastic succession and abundant borehole data.

  7. Composite Calderas: The Long and Short of it

    Science.gov (United States)

    Gravley, D. M.; Hasegawa, T.; Nakagawa, M.; Wilson, C. J.

    2006-12-01

    Calderas formed in supereruptions are normally linked to a single magma body. However, caldera formation, regional tectonics, and multiple magma bodies may interact to form composite structures with complex geometries. The term composite caldera is often used without reference as to whether the `composite' is in time or space. Three examples of composite caldera styles from New Zealand and Japan show field, geophysical, geochemical and isotopic evidence to suggest that current models for the size, shape and evolution of calderas may be too simplistic. In our examples, multiple separate magma bodies distributed in either space or time, or both, may play a significant role in composite caldera formation. Multiple, clustered collapse events incremental in time: Akan caldera in Hokkaido appears to be a single, rectangular shaped caldera. However, the identification of 17 eruptive units spanning >1 Myr suggests that the caldera evolved incrementally over time and space. New gravity data shows that the caldera is actually a daisy-chain of 3 distinct collapse structures that can be correlated, using lithic componentry, to 3 major geochemical groups in the eruptive products. Multiple, clustered collapse events in a single eruption sequence: Shikotsu caldera in Hokkaido was originally thought to have formed following the eruption of a single large zoned magma chamber. However, the caldera-related deposits are characterized by several geochemically distinct pumice types that can not have been accommodated in a single magma system. Our studies suggest that the variations in pumice compositions are consistent with multiple distinct magma bodies feeding coeval eruptions from several vent sources within an area that collapsed to form a single caldera. Paired calderas with linking eruption-related regional faulting: Rotorua and Ohakuri calderas in New Zealand are 30 km apart and formed in close succession during a complex but virtually continuous eruption sequence at ca. 240 ka

  8. Reconstruction of caldera collapse and resurgence processes in the offshore sector of the Campi Flegrei caldera (Italy)

    Science.gov (United States)

    Steinmann, Lena; Spiess, Volkhard; Sacchi, Marco

    2015-04-01

    Large collapse calderas are associated with exceptionally explosive volcanic eruptions, which are capable of triggering a global catastrophe second only to that from a giant meteorite impact. Therefore, active calderas have attracted significant attention in both scientific communities and governmental institutions worldwide. One prime example of a large collapse caldera can be found in southern Italy, more precisely in the northern Bay of Naples within the Campi Flegrei Volcanic Area. The Campi Flegrei caldera covers an area of approximately 200 km² defined by a quasi-circular depression, half onland, half offshore. It is still under debate whether the caldera formation was related to only one ignimbritic eruption namely the Neapolitan Yellow Tuff (NYT) eruption at 15 ka or if it is a nested-caldera system related to the NYT and the Campanian Ignimbrite eruption at 39 ka. During the last 40 years, the Campi Flegrei caldera has experienced episodes of unrest involving significant ground deformation and seismicity, which have nevertheless not yet led to an eruption. Besides these short-term episodes of unrest, long-term ground deformation with rates of several tens of meters within a few thousand years can be observed in the central part of the caldera. The source of both short-term and long-term deformation is still under debate and possibly related to a shallow hydrothermal system and caldera resurgence attributed to a deeper magma chamber, respectively. Understanding the mechanisms for unrest and eruptions is of paramount importance as a future eruption of the Campi Flegrei caldera would expose more than 500,000 people to the risk of pyroclastic flows. This study is based on a dense grid (semi-3D) of high-resolution multi-channel seismic profiles acquired in the offshore sector of the Campi Flegrei caldera. The seismic lines show evidence for the escape of fluids and/or gases along weak zones such as faults, thereby supporting the existence of a hydrothermal

  9. Searching for patterns in caldera unrest

    Science.gov (United States)

    Sandri, Laura; Acocella, Valerio; Newhall, Chris

    2017-07-01

    The ultimate goal of volcanology is forecasting eruptions. This task is particularly challenging at calderas, where unrest is frequent, affects wider areas and its evidence is often masked by the activity of hydrothermal systems. A recent study has compiled a database on caldera unrest, derived from seismicity, geodetic, gravity, and geochemical monitoring data at calderas worldwide, from 1988 to 2014. Here we exploit this database, searching for the most recurring features of unrest and, in turn, its possible dynamics. In particular, we focus on (a) the duration of unrest at calderas; (b) recurring patterns in unrest; (c) unrest episodes culminating in eruptions, including time-predictability or size-predictability and a multivariate regression analysis. Our analysis indicates that preeruptive unrest is shorter than noneruptive unrest, particularly with open or semiplugged calderas, calderas with mafic or mixed composition of past eruptive products, or unrest driven by mafic magma; conversely, lack of data on preeruptive unrest driven by felsic magma and/or at felsic or plugged calderas prevents an analysis of these specific subsets. In addition, 72% of preeruptive unrest lasts reliable to characterize preeruptive unrest. Our analysis suggests that magma may withstand only a limited period of "eruptability," before becoming stored in the upper crust.

  10. Central San Juan caldera cluster: Regional volcanic framework

    Science.gov (United States)

    Lipman, Peter W.

    2000-01-01

    Eruption of at least 8800 km3 of dacitic-rhyolitic magma as 9 major ash-slow sheets (individually 150-5000 km3) was accompanied by recurrent caldera subsidence between 28.3 and about 26.5 Ma in the central San Juan Mountains, Colorado. Voluminous andesitic-decitic lavas and breccias were erupted from central volcanoes prior to the ash-flow eruptions, and similar lava eruptions continued within and adjacent to the calderas during the period of explosive volcanism, making the central San Juan caldera cluster an exceptional site for study of caldera-related volcanic processes. Exposed calderas vary in size from 10 to 75 km in maximum diameter, the largest calderas being associated with the most voluminous eruptions. After collapse of the giant La Garita caldera during eruption if the Fish Canyon Tuff at 17.6 Ma, seven additional explosive eruptions and calderas formed inside the La Garita depression within about 1 m.y. Because of the nested geometry, maximum loci of recurrently overlapping collapse events are inferred to have subsided as much as 10-17 km, far deeper than the roof of the composite subvolcanic batholith defined by gravity data, which represents solidified caldera-related magma bodies. Erosional dissection to depths of as much as 1.5 km, although insufficient to reach the subvolcanic batholith, has exposed diverse features of intracaldera ash-flow tuff and interleaved caldera-collapse landslide deposits that accumulated to multikilometer thickness within concurrently subsiding caldera structures. The calderas display a variety of postcollapse resurgent uplift structures, and caldera-forming events produced complex fault geometries that localized late mineralization, including the epithermal base- and precious-metal veins of the well-known Creede mining district. Most of the central San Juan calderas have been deeply eroded, and their identification is dependent on detailed geologic mapping. In contrast, the primary volcanic morphology of the

  11. Geomorphological classification of post-caldera volcanoes in the Buyan-Bratan caldera, North Bali, Indonesia

    Science.gov (United States)

    Okuno, Mitsuru; Harijoko, Agung; Wayan Warmada, I.; Watanabe, Koichiro; Nakamura, Toshio; Taguchi, Sachihiro; Kobayashi, Tetsuo

    2017-12-01

    A landform of the post-caldera volcanoes (Lesung, Tapak, Sengayang, Pohen, and Adeng) in the Buyan-Bratan caldera on the island of Bali, Indonesia can be classified by topographic interpretation. The Tapak volcano has three craters, aligned from north to south. Lava effused from the central crater has flowed downward to the northwest, separating the Tamblingan and Buyan Lakes. This lava also covers the tip of the lava flow from the Lesung volcano. Therefore, it is a product of the latest post-caldera volcano eruption. The Lesung volcano also has two craters, with a gully developing on the pyroclastic cone from the northern slope to the western slope. Lava from the south crater has flowed down the western flank, beyond the caldera rim. Lava distributed on the eastern side from the south also surrounds the Sengayang volcano. The Adeng volcano is surrounded by debris avalanche deposits from the Pohen volcano. Based on these topographic relationships, Sengayang volcano appears to be the oldest of the post-caldera volcanoes, followed by the Adeng, Pohen, Lesung, and Tapak volcanoes. Coarse-grained scoria falls around this area are intercalated with two foreign tephras: the Samalas tephra (1257 A.D.) from Lombok Island and the Penelokan tephra (ca. 5.5 kBP) from the Batur caldera. The source of these scoria falls is estimated to be either the Tapak or Lesung volcano, implying that at least two volcanoes have erupted during the Holocene period.

  12. An ignimbrite caldera from the bottom up: Exhumed floor and fill of the resurgent Bonanza caldera, Southern Rocky Mountain volcanic field, Colorado

    Science.gov (United States)

    Lipman, Peter W.; Zimmerer, Matthew J.; McIntosh, William C.

    2015-01-01

    Among large ignimbrites, the Bonanza Tuff and its source caldera in the Southern Rocky Mountain volcanic field display diverse depositional and structural features that provide special insights concerning eruptive processes and caldera development. In contrast to the nested loci for successive ignimbrite eruptions at many large multicyclic calderas elsewhere, Bonanza caldera is an areally isolated structure that formed in response to a single ignimbrite eruption. The adjacent Marshall caldera, the nonresurgent lava-filled source for the 33.9-Ma Thorn Ranch Tuff, is the immediate precursor for Bonanza, but projected structural boundaries of two calderas are largely or entirely separate even though the western topographic rim of Bonanza impinges on the older caldera. Bonanza, source of a compositionally complex regional ignimbrite sheet erupted at 33.12 ± 0.03 Ma, is a much larger caldera system than previously recognized. It is a subequant structure ∼20 km in diameter that subsided at least 3.5 km during explosive eruption of ∼1000 km3 of magma, then resurgently domed its floor a similar distance vertically. Among its features: (1) varied exposure levels of an intact caldera due to rugged present-day topography—from Paleozoic and Precambrian basement rocks that are intruded by resurgent plutons, upward through precaldera volcanic floor, to a single thickly ponded intracaldera ignimbrite (Bonanza Tuff), interleaved landslide breccia, and overlying postcollapse lavas; (2) large compositional gradients in the Bonanza ignimbrite (silicic andesite to rhyolite ignimbrite; 60%–76% SiO2); (3) multiple alternations of mafic and silicic zones within a single ignimbrite, rather than simple upward gradation to more mafic compositions; (4) compositional contrasts between outflow sectors of the ignimbrite (mainly crystal-poor rhyolite to east, crystal-rich dacite to west); (5) similarly large compositional diversity among postcollapse caldera-fill lavas and resurgent

  13. Thermally-assisted Magma Emplacement Explains Restless Calderas

    Science.gov (United States)

    Amoruso, A.; Crescentini, L.; D'Antonio, M.; Acocella, V.

    2017-12-01

    Many calderas show repeated unrest over centuries. Though probably induced by magma, this unique behaviour is not understood and its dynamics remains elusive. To better understand these restless calderas, we interpret deformation data and build thermal models of Campi Flegrei, Italy, which is the best-known, yet most dangerous calderas, lying to the west of Naples and restless since the 1950s at least.Our elaboration of the geodetic data indicates that the inflation and deflation of magmatic sources at the same location explain most deformation, at least since the build-up of the last 1538 AD eruption. However, such a repeated magma emplacement requires a persistently hot crust.Our thermal models show that the repeated emplacement was assisted by the thermal anomaly created by magma that was intruded at shallow depth 3 ka before the last eruption and, in turn, contributed to maintain the thermal anomaly itself. This may explain the persistence of the magmatic sources promoting the restless behaviour of the Campi Flegrei caldera; moreover, it explains the crystallization, re-melting and mixing among compositionally distinct magmas recorded in young volcanic rocks.Available information at other calderas highlights similarities to Campi Flegrei, in the pattern and cause of unrest. All monitored restless calderas have either geodetically (Yellowstone, Aira Iwo-Jima, Askja, Fernandina and, partly, Long Valley) or geophysically (Rabaul, Okmok) detected sill-like intrusions inducing repeated unrest. Some calderas (Yellowstone, Long Valley) also show stable deformation pattern, where inflation insists on and mimics the resurgence uplift. The common existence of sill-like sources, also responsible for stable deformation patterns, in restless calderas suggests close similarities to Campi Flegrei. This suggests a wider applicability of our model of thermally-assisted sill emplacement, to be tested by future studies to better understand not only the dynamics of restless

  14. Location of silicic caldera formation in arc settings

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Gwyneth R; Mahood, Gail A [Department of Geological and Environmental Sciences, Stanford University, 450 Serra, Mall, Building 320, Stanford, CA 94305-2115 (United States)

    2008-10-01

    Silicic calderas are the surface expressions of silicic magma chambers, and thus their study may yield information about what tectonic and crustal features favor the generation of evolved magma. The goal of this study is to determine whether silicic calderas in arc settings are preferentially located behind the volcanic front. After a global analysis of young, arc-related calderas, we find that silicic calderas at continental margins do form over a wide area behind the front, as compared to other types of arc volcanoes.

  15. Krakatau caldera deposits: revisited and verification by geophysical means

    Directory of Open Access Journals (Sweden)

    Izumi Yokoyama

    2014-10-01

    Full Text Available  One of the differences between volcanic craters and calderas is that the latter bottoms are flatways filled with caldera deposit with lower density in comparison to country rocks. The 1883 Krakatau eruption affords us important knowledge on caldera formation even if it was not observed with modern sophisticated instruments. First, volcanic activities of the Krakatau Islands before and after the 1883 eruption are reexamined: previous suppositions involving a caldera-forming eruption of the proto-Krakatau prior to 1883 proved to be unsupported by the bathymetric topographies and gravity anomalies on and around the Krakatau Islands. Then, Anak Krakatau is interpreted as a parasitic cone of the main Krakatau volcano. As supplementary knowledge to discussion of caldera deposits, the results of drillings at several calderas in Japan and Mexico are introduced. Mass deficiency of the caldera deposit at Krakatau caldera is estimated by the gravity anomaly observed there and converted to probable volume with suitable density. For quantitative examination of the subsurface structure beneath the Krakatau complex, spatial distributions of seismic S-wave attenuation and Vp/Vs ratios have been already studied by temporary seismological observations and their results have been published. The high ratios of Vp/Vs observed approximately at Krakatau caldera may be attributable to the caldera deposit that is low density and contain much water. As additional remarks, a zone having both the characters, S-wave attenuation and zones of relatively high Vp/Vs ratio, may be a probable magma reservoir centering at a depth of about 10 km.

  16. Post-supereruption recovery at Toba Caldera.

    Science.gov (United States)

    Mucek, Adonara E; Danišík, Martin; de Silva, Shanaka L; Schmitt, Axel K; Pratomo, Indyo; Coble, Matthew A

    2017-05-16

    Large calderas, or supervolcanoes, are sites of the most catastrophic and hazardous events on Earth, yet the temporal details of post-supereruption activity, or resurgence, remain largely unknown, limiting our ability to understand how supervolcanoes work and address their hazards. Toba Caldera, Indonesia, caused the greatest volcanic catastrophe of the last 100 kyr, climactically erupting ∼74 ka. Since the supereruption, Toba has been in a state of resurgence but its magmatic and uplift history has remained unclear. Here we reveal that new 14 C, zircon U-Th crystallization and (U-Th)/He ages show resurgence commenced at 69.7±4.5 ka and continued until at least ∼2.7 ka, progressing westward across the caldera, as reflected by post-caldera effusive lava eruptions and uplifted lake sediment. The major stratovolcano north of Toba, Sinabung, shows strong geochemical kinship with Toba, and zircons from recent eruption products suggest Toba's climactic magma reservoir extends beneath Sinabung and is being tapped during eruptions.

  17. Thermally-assisted Magma Emplacement Explains Restless Calderas.

    Science.gov (United States)

    Amoruso, Antonella; Crescentini, Luca; D'Antonio, Massimo; Acocella, Valerio

    2017-08-11

    Many calderas show repeated unrest over centuries. Though probably induced by magma, this unique behaviour is not understood and its dynamics remains elusive. To better understand these restless calderas, we interpret deformation data and build thermal models of Campi Flegrei caldera, Italy. Campi Flegrei experienced at least 4 major unrest episodes in the last decades. Our results indicate that the inflation and deflation of magmatic sources at the same location explain most deformation, at least since the build-up of the last 1538 AD eruption. However, such a repeated magma emplacement requires a persistently hot crust. Our thermal models show that this repeated emplacement was assisted by the thermal anomaly created by magma that was intruded at shallow depth ~3 ka before the last eruption. This may explain the persistence of the magmatic sources promoting the restless behaviour of the Campi Flegrei caldera; moreover, it explains the crystallization, re-melting and mixing among compositionally distinct magmas recorded in young volcanic rocks. Our model of thermally-assisted unrest may have a wider applicability, possibly explaining also the dynamics of other restless calderas.

  18. Gravity-height correlations for unrest at calderas

    Science.gov (United States)

    Berrino, G.; Rymer, H.; Brown, G. C.; Corrado, G.

    1992-11-01

    Calderas represent the sites of the world's most serious volcanic hazards. Although eruptions are not frequent at such structures on the scale of human lifetimes, there are nevertheless often physical changes at calderas that are measurable over periods of years or decades. Such calderas are said to be in a state of unrest, and it is by studying the nature of this unrest that we may begin to understand the dynamics of eruption precursors. Here we review combined gravity and elevation data from several restless calderas, and present new data on their characteristic signatures during periods of inflation and deflation. We find that unless the Bouguer gravity anomaly at a caldera is extremely small, the free-air gradient used to correct gravity data for observed elevation changes must be the measured or calculated gradient, and not the theoretical gradient, use of which may introduce significant errors. In general, there are two models that fit most of the available data. The first involves a Mogi-type point source, and the second is a Bouguer-type infinite horizontal plane source. The density of the deforming material (usually a magma chamber) is calculated from the gravity and ground deformation data, and the best fitting model is, to a first approximation, the one producing the most realistic density. No realistic density is obtained where there are real density changes, or where the data do not fit the point source or slab model. We find that a point source model fits most of the available data, and that most data are for periods of caldera inflation. The limited examples of deflation from large silicic calderas indicate that the amount of mass loss, or magma drainage, is usually much less than the mass gain during the preceding magma intrusion. In contrast, deflationary events at basaltic calderas formed in extensional tectonic environments are associated with more significant mass loss as magma is injected into the associated fissure swarms.

  19. Post-collapse evolution of a coastal caldera system: Insights from a 3D multichannel seismic survey from the Campi Flegrei caldera (Italy)

    Science.gov (United States)

    Steinmann, Lena; Spiess, Volkhard; Sacchi, Marco

    2018-01-01

    In this study we present the first 3D high-resolution multichannel seismic dataset from a (partly) submerged caldera setting, the Campi Flegrei caldera (CFc). Our work aims at examining the spatial and temporal evolution of the CFc since the last caldera-forming event, the Neapolitan Yellow Tuff (NYT, 15 ka) eruption. The main objectives are to investigate the caldera's shallow ( 200 m) outer caldera ring-fault zone. The seismic data revealed that the NYT collapse occurred exclusively along the inner caldera ring-fault and that the related NYT caldera depression is filled with on average 61 m of sediment deposited between 15 and 8.6 ka. The geometry of the inner ring-fault, consisting of four fault segments, seems to be strongly influenced by regional NW-SE and NE SW-trending faults. Furthermore, we found that the ring-faults have acted as pathway for the recent (Bank (10.3-9.5 ka), Nisida Island ( 3.98 ka), and Capo Miseno (3.7 ka) eruptions, yielding DRE values of 0.15 km3, 0.1 km3, and 0.08 km3, respectively, and an explosive magnitude of at least moderate-large scale (VEI 3). Our findings highlight that eruption volumes may be underestimated by 3 to 4 times if the submerged portion of a (partly) submerged caldera is not considered, implying severe consequences for the hazard and risk evaluation. The spatial response of the post-collapse (< 15 ka) depositional environment to volcanic activity, deformational processes and sea-level variations is presented in a comprehensive 3D evolutionary model.

  20. Magma storage in a strike-slip caldera.

    Science.gov (United States)

    Saxby, J; Gottsmann, J; Cashman, K; Gutiérrez, E

    2016-07-22

    Silicic calderas form during explosive volcanic eruptions when magma withdrawal triggers collapse along bounding faults. The nature of specific interactions between magmatism and tectonism in caldera-forming systems is, however, unclear. Regional stress patterns may control the location and geometry of magma reservoirs, which in turn may control the spatial and temporal development of faults. Here we provide new insight into strike-slip volcano-tectonic relations by analysing Bouguer gravity data from Ilopango caldera, El Salvador, which has a long history of catastrophic explosive eruptions. The observed low gravity beneath the caldera is aligned along the principal horizontal stress orientations of the El Salvador Fault Zone. Data inversion shows that the causative low-density structure extends to ca. 6 km depth, which we interpret as a shallow plumbing system comprising a fractured hydrothermal reservoir overlying a magmatic reservoir with vol% exsolved vapour. Fault-controlled localization of magma constrains potential vent locations for future eruptions.

  1. Lithium deposits hosted in intracontinental rhyolite calderas

    Science.gov (United States)

    Benson, T. R.; Coble, M. A.; Mahood, G. A.

    2017-12-01

    Lithium (Li) is classified as a technology-critical element due to the increasing demand for Li-ion batteries, which have a high power density and a relatively low cost that make them optimal for energy storage in mobile electronics, the electrical power grid, and hybrid and electric vehicles. Given that many projections for Li demand exceed current economic reserves and the market is dominated by Australia and Chile, discovery of new domestic Li resources will help diversify the supply chain and keep future technology costs down. Here we show that lake sediments preserved within intracontinental rhyolite calderas have the potential to host Li deposits on par with some of the largest Li brine deposits in the world. We compare Li concentrations of rhyolite magmas formed in a variety of tectonic settings using in situ SHRIMP-RG measurements of homogenized quartz-hosted melt inclusions. Rhyolite magmas that formed within thick, felsic continental crust (e.g., Yellowstone and Hideaway Park, United States) display moderate to extreme Li enrichment (1,500 - 9,000 ppm), whereas magmas formed in thin crust or crust comprised of accreted arc terranes (e.g., Pantelleria, Italy and High Rock, Nevada) contain Li concentrations less than 500 ppm. When the Li-enriched magmas erupt to form calderas, the cauldron depression serves as an ideal catchment within which meteoric water that leached Li from intracaldera ignimbrite, nearby outflow ignimbrite, and caldera-related lavas can accumulate. Additional Li is concentrated in the system through near-neutral, low-temperature hydrothermal fluids circulated along ring fractures as remnant magma solidifies and degasses. Li-bearing hectorite and illite clays form in this alteration zone, and when preserved in the geological record, can lead to a large Li deposit like the 2 Mt Kings Valley Li deposit in the McDermitt Caldera, Nevada. Because more than 100 large Cenozoic calderas occur in the western United States that formed on eruption

  2. Stable Isotopes of Tilted Ignimbrite Calderas in Nevada

    Science.gov (United States)

    John, D. A.; Watts, K. E.; Hofstra, A. H.; Colgan, J. P.; Henry, C.; Bindeman, I. N.

    2013-12-01

    Mid-Tertiary calderas are exceptionally well exposed in tilted fault blocks of the northern Great Basin, facilitating detailed evolutionary models of their magmatic-hydrothermal systems. The 29.4 Ma Job Canyon caldera, the oldest of 3 overlapping calderas in the Stillwater Range, west-central Nevada, is tilted ~90° exposing a 10-km-thick section of the crust. Large parts of the >7 km-diameter caldera system, including >2 km thickness of intracaldera rhyolitic tuff, lower parts of an ~2 km thick sequence of post-caldera intermediate lavas, and the upper 500 m of the resurgent granodioritic IXL pluton, were pervasively altered to propylitic, argillic, and sericitic assemblages. Sparse quartz×calcite veins cut the tuff. δ18O values of altered whole rock samples range from +4.8 to -9.1‰ but are mostly -6 to -9‰ at paleodepths >2 km. Calculated magmatic δ18O and δD values range from +6.4 to 8.2‰ and ~-70‰, respectively. Calculated fluid compositions using temperatures from fluid inclusions and mineral assemblages are δ18OH2O=-9.5 to -15‰ and δDH2O=-125 to -135‰ (chlorite) and -70 to -80‰ (epidote). Chlorite-whole rock data suggest fluids that were derived from moderately 18O-exchanged meteoric water. Fault blocks in north-central Nevada expose a >5 km upper crustal cross section through the 12-17 x 20 km, 34 Ma Caetano caldera, including >3 km thickness intracaldera rhyolitic Caetano Tuff. Asymmetric caldera subsidence left a depression >1 km deep partly filled with a lake. Magma resurgence and emplacement of shallow granite porphyry plutons drove a hydrothermal system that altered >120 km2 of the caldera to depths >1.5 km. Alteration was focused in an early granite porphyry intrusion and surrounding upper Caetano Tuff and lacustrine sediments. Early pervasive quartz-kaolinite-pyrite alteration grades outward and downward into more restricted quartz-illite/smectite-pyrite alteration. Hematite, quartz, and barite veins and hydrothermal breccias cut

  3. Geology and structure of the Malpaso caldera and El Ocote ignimbrite, Aguascalientes, Mexico

    International Nuclear Information System (INIS)

    Nieto-Obregon, Jorge; Aguirre-DIaz, Gerardo

    2008-01-01

    A new caldera, named Malpaso, is reported west of the city of Aguascalientes, Mexico. The Malpaso caldera is a volcano-tectonic depression, highly fractured and faulted, and was filled by voluminous pyroclastic products related to the caldera collapse. Due to these characteristics it as a graben caldera. It is truncated by younger normal faults of the Calvillo and Aguascalientes grabens. In this work we present a summary of the geologic and structural observations on this caldera, as well as a description of the main caldera product, the high-grade El Ocote ignimbrite.

  4. Geology and structure of the Malpaso caldera and El Ocote ignimbrite, Aguascalientes, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Nieto-Obregon, Jorge [Facultad de IngenierIa, UNAM, Coyoacan, 04510, Mexico D.F. (Mexico); Aguirre-DIaz, Gerardo [Centro de Geociencias, UNAM, Campus Juriquilla, 76220, Queretaro, Qro. (Mexico)], E-mail: nieto@servidor.unam.mx, E-mail: ger@geociencias.unam.mx

    2008-10-01

    A new caldera, named Malpaso, is reported west of the city of Aguascalientes, Mexico. The Malpaso caldera is a volcano-tectonic depression, highly fractured and faulted, and was filled by voluminous pyroclastic products related to the caldera collapse. Due to these characteristics it as a graben caldera. It is truncated by younger normal faults of the Calvillo and Aguascalientes grabens. In this work we present a summary of the geologic and structural observations on this caldera, as well as a description of the main caldera product, the high-grade El Ocote ignimbrite.

  5. Anfibios y reptiles del valle del Mezquital, Hidalgo, México Amphibians and reptiles from the Valle del Mezquital, Hidalgo, Mexico

    Directory of Open Access Journals (Sweden)

    Leonardo Fernández-Badillo

    2010-12-01

    Full Text Available El valle del Mezquital, Hidalgo, México, es un área de gran riqueza biológica; sin embargo, se desconoce mucho sobre su herpetofauna, por lo que se realizó una lista de anfibios y reptiles de 3 zonas del valle. Se analizó su distribución por tipo de vegetación, se registraron los microhábitats utilizados, así como la abundancia relativa. Se llevaron a cabo 12 salidas mensuales durante 1 año, con 108 días de muestreo. Se realizaron recorridos sobre transectos, en 9 tipos de vegetación. La herpetofauna del área de estudio está integrada por 37 especies (7 anfibios y 30 reptiles, de las cuales 8 se registran por primera vez para el valle del Mezquital. La mayoría de las especies se presentaron en las zonas de cultivo (26, 14 especies en los de la zona templada y 13 en los de la zona de riego. La herpetofauna del valle del Mezquital utiliza un total de 27 tipos de microhábitats, siendo "bajo roca" donde se registró el mayor número de especies (22. La mayoría de las especies tanto de anfibios como de reptiles fueron consideradas raras.Valle del Mezquital Hidalgo, Mexico is known for its high biological richness, but little is known about its herpetofauna. A study to list the amphibians and reptiles of 3 different zones at the Valle del Mezquital was carried out. We analyzed their distribution in different types of vegetation, their microhabitat and relative abundance in 12 monthly trips during 1 year for a total of 108 days. We sampled transects over 9 types of vegetation. Thirty species have been reported for this area (7 amphibians, 30 reptiles, 8 reported for the first time from Valle del Mezquital. Most of the species were present within crops (26, 14 within the temperate zone and 13 within the irrigation zone. The herpetofauna at Valle del Mezquital uses 27 different microhabitat, being "under rock" the most used by 22 species. Most of the species, both amphibians and reptiles were considered rare.

  6. Post-eruptive flooding of Santorini caldera and implications for tsunami generation

    Science.gov (United States)

    Nomikou, P.; Druitt, T. H.; Hübscher, C.; Mather, T. A.; Paulatto, M.; Kalnins, L. M.; Kelfoun, K.; Papanikolaou, D.; Bejelou, K.; Lampridou, D.; Pyle, D. M.; Carey, S.; Watts, A. B.; Weiß, B.; Parks, M. M.

    2016-01-01

    Caldera-forming eruptions of island volcanoes generate tsunamis by the interaction of different eruptive phenomena with the sea. Such tsunamis are a major hazard, but forward models of their impacts are limited by poor understanding of source mechanisms. The caldera-forming eruption of Santorini in the Late Bronze Age is known to have been tsunamigenic, and caldera collapse has been proposed as a mechanism. Here, we present bathymetric and seismic evidence showing that the caldera was not open to the sea during the main phase of the eruption, but was flooded once the eruption had finished. Inflow of water and associated landsliding cut a deep, 2.0–2.5 km3, submarine channel, thus filling the caldera in less than a couple of days. If, as at most such volcanoes, caldera collapse occurred syn-eruptively, then it cannot have generated tsunamis. Entry of pyroclastic flows into the sea, combined with slumping of submarine pyroclastic accumulations, were the main mechanisms of tsunami production. PMID:27824353

  7. How summit calderas collapse on basaltic volcanoes: new insights from the April 2007 caldera collapse of Piton de la Fournaise volcano

    Energy Technology Data Exchange (ETDEWEB)

    Michon, Laurent; Catry, Thibault; Merle, Olivier [Laboratoire GeoSciences Reunion, Universite de la Reunion, Institut de Physique du Globe de Paris, CNRS, UMR 7154 - Geologie des Systemes Volcaniques, 15 avenue Rene Cassin, 97715 Saint Denis (France); Villeneuve, Nicolas [Institut de Recherche pour le Developpement, US 140, BP172, 97492 Sainte-Clotilde cedex (France)], E-mail: laurent.michon@univ-reunion.fr

    2008-10-01

    In April 2007, Piton de la Fournaise volcano experienced a caldera collapse during its largest historical eruption. We present here the resulting deformation and a synthesis of the seismicity recorded during recent caldera collapses. It allows us to propose a unifying mechanism that explains the pulsating collapse dynamics.

  8. A kuroko-type polymetallic sulfide deposit in a submarine silicic caldera

    Science.gov (United States)

    Iizasa; Fiske; Ishizuka; Yuasa; Hashimoto; Ishibashi; Naka; Horii; Fujiwara; Imai; Koyama

    1999-02-12

    Manned submersible studies have delineated a large and actively growing Kuroko-type volcanogenic massive sulfide deposit 400 kilometers south of Tokyo in Myojin Knoll submarine caldera. The sulfide body is located on the caldera floor at a depth of 1210 to 1360 meters, has an area of 400 by 400 by 30 meters, and is notably rich in gold and silver. The discovery of a large Kuroko-type polymetallic sulfide deposit in this arc-front caldera raises the possibility that the numerous unexplored submarine silicic calderas elsewhere might have similar deposits.

  9. Kaguyak dome field and its Holocene caldera, Alaska Peninsula

    Science.gov (United States)

    Fierstein, J.; Hildreth, W.

    2008-01-01

    Kaguyak Caldera lies in a remote corner of Katmai National Park, 375??km SW of Anchorage, Alaska. The 2.5-by-3-km caldera collapsed ~ 5.8 ?? 0.2??ka (14C age) during emplacement of a radial apron of poorly pumiceous crystal-rich dacitic pyroclastic flows (61-67% SiO2). Proximal pumice-fall deposits are thin and sparsely preserved, but an oxidized coignimbrite ash is found as far as the Valley of Ten Thousand Smokes, 80??km southwest. Postcaldera events include filling the 150-m-deep caldera lake, emplacement of two intracaldera domes (61.5-64.5% SiO2), and phreatic ejection of lakefloor sediments onto the caldera rim. CO2 and H2S bubble up through the lake, weakly but widely. Geochemical analyses (n = 148), including pre-and post-caldera lavas (53-74% SiO2), define one of the lowest-K arc suites in Alaska. The precaldera edifice was not a stratocone but was, instead, nine contiguous but discrete clusters of lava domes, themselves stacks of rhyolite to basalt exogenous lobes and flows. Four extracaldera clusters are mid-to-late Pleistocene, but the other five are younger than 60??ka, were truncated by the collapse, and now make up the steep inner walls. The climactic ignimbrite was preceded by ~ 200??years by radial emplacement of a 100-m-thick sheet of block-rich glassy lava breccia (62-65.5% SiO2). Filling the notches between the truncated dome clusters, the breccia now makes up three segments of the steep caldera wall, which beheads gullies incised into the breccia deposit prior to caldera formation. They were probably shed by a large lava dome extruding where the lake is today.

  10. Stratigraphy of the Kasei Valles region, Mars

    Science.gov (United States)

    Robinson, Mark S.; Tanaka, Kenneth L.

    1987-01-01

    The thicknesses and geomorphology of the two principal stratigraphic units exposed in Kasei Valles to aid in interpreting the nature of crustal materials and the history of the channeling events in the area are identified and described. Previous studies of Kasei Valles have related the channel landforms to glacial flow, catastrophic flooding, and large-scale eolian erosion. The two units (an upper and a lower unit) form thick sheets, each having distinct geomorphologic features. Thicknesses of the unit were determined through preliminary stereogrammetric profiles taken across many sections of western Kasei Valles and shadow measurements taken of scarp heights from calibrated Viking images having sun angles less than 25 degrees; DN values were examined to confirm that true shadows were observed.

  11. Seismic constraints on caldera dynamics from the 2015 Axial Seamount eruption.

    Science.gov (United States)

    Wilcock, William S D; Tolstoy, Maya; Waldhauser, Felix; Garcia, Charles; Tan, Yen Joe; Bohnenstiehl, DelWayne R; Caplan-Auerbach, Jacqueline; Dziak, Robert P; Arnulf, Adrien F; Mann, M Everett

    2016-12-16

    Seismic observations in volcanically active calderas are challenging. A new cabled observatory atop Axial Seamount on the Juan de Fuca ridge allows unprecedented real-time monitoring of a submarine caldera. Beginning on 24 April 2015, the seismic network captured an eruption that culminated in explosive acoustic signals where lava erupted on the seafloor. Extensive seismic activity preceding the eruption shows that inflation is accommodated by the reactivation of an outward-dipping caldera ring fault, with strong tidal triggering indicating a critically stressed system. The ring fault accommodated deflation during the eruption and provided a pathway for a dike that propagated south and north beneath the caldera's east wall. Once north of the caldera, the eruption stepped westward, and a dike propagated along the extensional north rift. Copyright © 2016, American Association for the Advancement of Science.

  12. Piston to funnel - successive growth of a collapsed caldera during the Miyakejima 2000 eruption

    International Nuclear Information System (INIS)

    Geshi, Nobuo

    2008-01-01

    We present an analysis of caldera evolution at Miyakejima in 2000. The caldera changed its structure from piston to funnel subsidence during its growth. The successive subsidence of the central block induced landslides at the caldera wall, which successively enlarged the diameter of the caldera.

  13. Piston to funnel - successive growth of a collapsed caldera during the Miyakejima 2000 eruption

    Energy Technology Data Exchange (ETDEWEB)

    Geshi, Nobuo [Geological Survey of Japan, AIST, 1-1-1 Higashi, Tsukuba Ibaraki 305-8567 (Japan)], E-mail: geshi-nob@aist.go.jp

    2008-10-01

    We present an analysis of caldera evolution at Miyakejima in 2000. The caldera changed its structure from piston to funnel subsidence during its growth. The successive subsidence of the central block induced landslides at the caldera wall, which successively enlarged the diameter of the caldera.

  14. Magma transfer at Campi Flegrei caldera (Italy) before the 1538 AD eruption.

    Science.gov (United States)

    Di Vito, Mauro A; Acocella, Valerio; Aiello, Giuseppe; Barra, Diana; Battaglia, Maurizio; Carandente, Antonio; Del Gaudio, Carlo; de Vita, Sandro; Ricciardi, Giovanni P; Ricco, Ciro; Scandone, Roberto; Terrasi, Filippo

    2016-08-25

    Calderas are collapse structures related to the emptying of magmatic reservoirs, often associated with large eruptions from long-lived magmatic systems. Understanding how magma is transferred from a magma reservoir to the surface before eruptions is a major challenge. Here we exploit the historical, archaeological and geological record of Campi Flegrei caldera to estimate the surface deformation preceding the Monte Nuovo eruption and investigate the shallow magma transfer. Our data suggest a progressive magma accumulation from ~1251 to 1536 in a 4.6 ± 0.9 km deep source below the caldera centre, and its transfer, between 1536 and 1538, to a 3.8 ± 0.6 km deep magmatic source ~4 km NW of the caldera centre, below Monte Nuovo; this peripheral source fed the eruption through a shallower source, 0.4 ± 0.3 km deep. This is the first reconstruction of pre-eruptive magma transfer at Campi Flegrei and corroborates the existence of a stationary oblate source, below the caldera centre, that has been feeding lateral eruptions for the last ~5 ka. Our results suggest: 1) repeated emplacement of magma through intrusions below the caldera centre; 2) occasional lateral transfer of magma feeding non-central eruptions within the caldera. Comparison with historical unrest at calderas worldwide suggests that this behavior is common.

  15. Caldera resurgence driven by magma viscosity contrasts.

    Science.gov (United States)

    Galetto, Federico; Acocella, Valerio; Caricchi, Luca

    2017-11-24

    Calderas are impressive volcanic depressions commonly produced by major eruptions. Equally impressive is the uplift of the caldera floor that may follow, dubbed caldera resurgence, resulting from magma accumulation and accompanied by minor eruptions. Why magma accumulates, driving resurgence instead of feeding large eruptions, is one of the least understood processes in volcanology. Here we use thermal and experimental models to define the conditions promoting resurgence. Thermal modelling suggests that a magma reservoir develops a growing transition zone with relatively low viscosity contrast with respect to any newly injected magma. Experiments show that this viscosity contrast provides a rheological barrier, impeding the propagation through dikes of the new injected magma, which stagnates and promotes resurgence. In explaining resurgence and its related features, we provide the theoretical background to account for the transition from magma eruption to accumulation, which is essential not only to develop resurgence, but also large magma reservoirs.

  16. Petrological cycles and caldera-forming events

    Science.gov (United States)

    Bachmann, O.; Deering, C. D.

    2012-12-01

    Many caldera-forming events can be framed within broad petrological cycles; volcanic stratigraphy typically defines a trend from mafic to more silicic magmas with time, culminating in the catastrophic evacuation of an upper crustal reservoir filled with the silicic magma, followed by a return to the eruption of more mafic magmas shortly after caldera collapse. Understanding how such cycles develop has clear implications for characterizing the current state of an active system. Here, we focus on a detailed examination of the well-exposed Quaternary Kos-Nisyros eruptive sequence (eastern Aegean arc) to frame a potential model for such cycles. On the basis of zircon U/Th/Pb ages, building the upper crustal magma chamber large enough to induce caldera collapse required at least a few hundred thousand years. This timeframe is necessary not only for the accumulation of large amounts of viscous, gas-rich silicic magma, but also to heat the upper crust sufficiently to allow the developing reservoir to be maintained above the solidus. In the Kos-Nisyros volcanic center, small eruptions precede the caldera-forming event and mark this period of thermal maturation as the system transitions from intermediate to silicic magma, reaching the most-evolved state only shortly prior to the caldera-forming event, the Kos Plateau Tuff (> 60 km3 of volatile-rich, high-silica rhyolite). The Kos Plateau Tuff was then followed by small-volume eruptions of more mafic magma (basaltic andesite, andesite, and dacites) that are characterized by a drier mineral assemblage. With time, the system transitioned back to cold, wet, high-SiO2 rhyolite. We suggest that the changes in magma composition and mineralogy following the caldera-forming event are due to a near-complete crystallization of the non-erupted mush in the upper crustal reservoir as it is abruptly decompressed during eruption. This rapid crystallization (1) leads to the formation of a porphyritic texture in the crystalline residual - a

  17. The Magmatic Plumbing System of the Campi Flegrei Caldera.

    Science.gov (United States)

    Lucia, C.; Ilenia, A.; Massimo, D.; Valeria, D.; Mauro, D.; Giovanni, O.

    2006-12-01

    The Campi Flegrei caldera is a nested and resurgent structure generated by at least two major collapses. Large sectors of the structural boundary of both calderas resulted from partial reactivation of pre-existing faults generated by regional tectonism. Its magmatic system is still active with the last eruption occurring in 1538 A.D. (Monte Nuovo), widespread fumaroles and hot springs activity, and the unrest episodes in the last 35 years, with a maximum net uplift of about 3.5 m in the Pozzuoli area. The definition of the history of the magmatic feeding system of this caldera, in terms of composition, time- scale and depth of crystallization, relation between composition of the erupted magma and structural position of the vent, and magma chamber processes, is of extreme importance for a better understanding of the dynamic conditions of the present day magma chamber and for evaluating of the extent to which the behavior of the magmatic system can be predicted. The Campi Flegrei caldera magmatic plumbing system is characterized by deep and shallow reservoirs. Campi Flegrei magmas originated in a subduction modified mantle source, stagnate at mid crustal level (20- 10 km depth), where they differentiated and are contaminated with the continental crust. From the "deep reservoir" shoshonitic to latitic magmas rise towards the surface along the NE aligned regional fault reactivated during the caldera collapse, whereas trachytic magmas rise mostly along faults and fractures bordering the resurgent block and the southern part of the Campi Flegrei caldera. Repeated arrival of trachytic to phonolitic magmas form shallow reservoirs at 4-3 km depth, in which differentiation and mixing processes occur before and during the eruption.

  18. A natural analogue for high-level waste in tuff: Chemical analysis and modeling of the Valles site

    International Nuclear Information System (INIS)

    Stockman, H.W.; Krumhansl, J.L.; Ho, C.K.; Kovach, L.; McConnell, V.S.

    1995-01-01

    The contact between an obsidian flow and a steep-walled tuff canyon was examined as an analogue for a high-level waste repository. The analogue site is located in the Valles Caldera in New Mexico, where a massive obsidian flow filled a paleocanyon in the Battleship Rock Tuff. The obsidian flow provided a heat source, analogous to waste panels or an igneous intrusion in a repository, and caused evaporation and migration of water. The tuff and obsidian samples were analyzed for major and trace elements and mineralogy by INAA, XRF, x-ray diffraction, and scanning electron microscopy and electron microprobe. Samples were also analyzed for D/H and 39 Ar/ 40 Ar isotopic composition. Overall, the effects of the heating event seem to have been slight and limited to the tuff nearest the contact. There is some evidence of devitrification and migration of volatiles in the tuff within 10 m of the contact, but variations in major and trace element chemistry are small and difficult to distinguish from the natural (pre-heating) variability of the rocks

  19. 14C ages for the ejecta from Kutcharo and Mashu calderas, eastern Hokkaido, Japan

    International Nuclear Information System (INIS)

    Yamamoto, Takahiro; Ito, Jun-ichi; Nakagawa, Mitsuhiro; Hasegawa, Takeshi; Kishimoto, Hiroshi

    2010-01-01

    Eruption ages of the ejecta from Kutcharo and Mashu calderas were systematically determined by 14 C dating. 16 charred samples were newly obtained from the Mashu and Nakashumbetsu Tephra Formations around the calderas and dated by AMS and β-counting methods. Examined units are Ma-d, Ma-e, Ma-f, Ma-j, Ma-k, Ma-l and Ml-a in the Mashu ejecta and 6 Nakashumbetsu tephra layers including Kutcharo Pumice Flow Deposit I (KpI), which is the youngest caldera-forming product from Kutcharo caldera. Results of the 14 C dating range from 3,660 ±40 yBP to 36,080±1,300 yBP, and are consistent with the tephrostratigraphy. Calendar age for KpI was newly calculated at almost 40 ka and this age shows there was about 70,000 years recurrence interval between KpI and KpIV caldera-forming eruptions. Mashu caldera has appeared on the eastern part of Kutcharo caldera immediately after the KpI eruption, and calendar age for its main caldera-forming eruption were determined at ca. BC 5,600. (author)

  20. Geophysical expression of caldera related volcanism, structures and mineralization in the McDermitt volcanic field

    Science.gov (United States)

    Rytuba, J. J.; Blakely, R. J.; Moring, B.; Miller, R.

    2013-12-01

    The High Rock, Lake Owyhee, and McDermitt volcanic fields, consisting of regionally extensive ash flow tuffs and associated calderas, developed in NW Nevada and SE Oregon following eruption of the ca. 16.7 Ma Steens flood basalt. The first ash flow, the Tuff of Oregon Canyon, erupted from the McDermitt volcanic field at 16.5Ma. It is chemically zoned from peralkaline rhyolite to dacite with trace element ratios that distinguish it from other ash flow tuffs. The source caldera, based on tuff distribution, thickness, and size of lithic fragments, is in the area in which the McDermitt caldera (16.3 Ma) subsequently formed. Gravity and magnetic anomalies are associated with some but not all of the calderas. The White Horse caldera (15.6 Ma), the youngest caldera in the McDermitt volcanic field has the best geophysical expression, with both aeromagnetic and gravity lows coinciding with the caldera. Detailed aeromagnetic and gravity surveys of the McDermitt caldera, combined with geology and radiometric surveys, provides insight into the complexities of caldera collapse, resurgence, post collapse volcanism, and hydrothermal mineralization. The McDermitt caldera is among the most mineralized calderas in the world, whereas other calderas in these three Mid Miocene volcanic fields do not contain important hydrothermal ore deposits, despite having similar age and chemistry. The McDermitt caldera is host to Hg, U, and Li deposits and potentially significant resources of Ga, Sb, and REE. The geophysical data indicate that post-caldera collapse intrusions were important in formation of the hydrothermal systems. An aeromagnetic low along the E caldera margin reflects an intrusion at a depth of 2 km associated with the near-surface McDermitt-hot-spring-type Hg-Sb deposit, and the deeper level, high-sulfidation Ga-REE occurrence. The Li deposits on the W side of the caldera are associated with a series of low amplitude, small diameter aeromagnetic anomalies that form a continuous

  1. Asymmetric growth of collapsed caldera by oblique subsidence during the 2000 eruption of Miyakejima, Japan

    Science.gov (United States)

    Geshi, Nobuo

    2009-04-01

    Oblique development of the ring faults reflecting the structural heterogeneities inside the volcano formed many asymmetric structures of Miyakejima 2000 AD caldera. The asymmetry includes (a) offset location of the ring faults with respect to the associated shallow magma chamber, (b) unequal outward migration of the caldera wall 600 m at the southeastern rim but only 200 m at the northwestern rim, (c) development of tilted terrace only at the southeastern caldera margin, (d) eruption sites and fumaroles being confined to the southern part of the caldera. Geophysical data, including ground deformation and seismic activity, indicates the offset of the location of the magma chamber about 2 km south of the caldera center on the surface. The ring faults propagated from the deflating magma chamber obliquely about 30 degrees toward the summit. The oblique subsidence of the cylindrical block formed a wider instable zone, particularly in the southeastern side of the ring fault that enhanced the larger outward migration of the caldera rim and also caused the formation of the outer half-ring fault bordering the tilting slope at the southern part. Ascending pass of the buoyant magma along the tilted ring faults was concentrated in the southern half of the caldera and consequently the distributions of the eruption sites and fumaroles are localized in the southern-half part of the caldera. The structure of the Miyakejima 2000 caldera with complete development of the ring faults, its high roof aspect ratio and oblique subsidence is clearly distinguishable from trapdoor-type caldera. The oblique development of the ring faults can be controlled by the mechanical contrast between the solidified conduits and surrounding fragile volcanic edifice. Asymmetric development of the Miyakejima caldera shows that the collapsed calderas are potential indicators of the heterogeneous structures inside of the volcano, particularly in the case of small-size caldera.

  2. Pre-eruptive conditions of the phonolitic magma from the El Abrigo caldera-forming eruption (Las Canadas caldera, Tenerife, Canary Islands)

    International Nuclear Information System (INIS)

    Marti, J; Andujar, J; Costa, F; Wolff, J A; Carroll, M R

    2008-01-01

    We have performed phase equilibrium experiments to determine the pre-eruptive conditions of the largest phonolitic caldera-forming eruption (∼20 km3 of DRE) that occurred on Tenerife (Canary Islands). The Abrigo ignimbrite was erupted during the last caldera-forming episode (ca. 190 ka), from the Canadas caldera. Comparison of the natural and experimental phase proportions and compositions indicates that the phonolite at the roof of the Abrigo magma reservoir was at 130 ± 50 MPa (corresponding to ca. 4 - 5 km below the surface), 825 ± 25 oC, with 3 ± 1 wt% dissolved H2O and fO2 at the Ni-NiO buffer ? 1 log unit. This shows that the magma that produced the largest ignimbrite on Tenerife was stored at relatively shallow depths but was water-undersaturated, and its eruption was probably triggered by input of fresh mafic magma.

  3. Pre-eruptive conditions of the phonolitic magma from the El Abrigo caldera-forming eruption (Las Canadas caldera, Tenerife, Canary Islands)

    Energy Technology Data Exchange (ETDEWEB)

    Marti, J; Andujar, J; Costa, F [Institute of Earth Sciences ' Jaume Almera' , CSIC, C/ Lluis Sole I Sabaris, s/n Barcelona, 08028 Spain (Spain); Wolff, J A [School of Earth and Environmental Sciences, Washington State University, Pullman, WA 99164-2812 (United States); Carroll, M R [Dipartimento di Scienze della Terra, Via Gentile III da Varano, Universita di Camerino, 62032 MC (Italy)], E-mail: jawolff@mail.wsu.edu, E-mail: Michael.carroll@unicam.it

    2008-10-01

    We have performed phase equilibrium experiments to determine the pre-eruptive conditions of the largest phonolitic caldera-forming eruption ({approx}20 km3 of DRE) that occurred on Tenerife (Canary Islands). The Abrigo ignimbrite was erupted during the last caldera-forming episode (ca. 190 ka), from the Canadas caldera. Comparison of the natural and experimental phase proportions and compositions indicates that the phonolite at the roof of the Abrigo magma reservoir was at 130 {+-} 50 MPa (corresponding to ca. 4 - 5 km below the surface), 825 {+-} 25 oC, with 3 {+-} 1 wt% dissolved H2O and fO2 at the Ni-NiO buffer ? 1 log unit. This shows that the magma that produced the largest ignimbrite on Tenerife was stored at relatively shallow depths but was water-undersaturated, and its eruption was probably triggered by input of fresh mafic magma.

  4. Exploration of Geothermal Natural Resources from Menengai Caldera at Naruku, Kenya

    Science.gov (United States)

    Patlan, E.; Wamalwa, A.; Thompson, L. E.; Kaip, G.; Velasco, A. A.

    2011-12-01

    The Menengai Caldera, a large, dormant volcano, lies near the city of Naruku, Kenya (0.20°S, 36.07°E) and presents a significant natural geothermal energy resource that will benefit local communities. Kenya continues to explore and exploit its only major energy resource: geothermal energy. The Geothermal Development Company (GDC) of Kenya and University of Texas at El Paso (UTEP) have initially deployed seven seismic stations to address the volcanic hazards and associated processes that occurs through the analysis of data collection from seismic sensors that record ground motion. Seven more sensors are planned to be deployed in Aug. 2011. In general, the internal state and activity of the caldera is an important component to the understanding of porosity of the fault system, which is derived from the magma movement of the hot spot, and for the exploitation of geothermal energy. We analyze data from March to May 2011 to investigate the role of earthquakes and faults in controlling the caldera processes, and we find 15 events occurred within the caldera. We will utilize the double difference earthquake location algorithm (HypoDD) to analyze the local events in order to find active faulting of the caldera and the possible location of the magma chamber. For future work, we will combine the exiting data with the new seismic station to image the location of the caldera magma chamber.

  5. Magnetic study of the Furnas caldera (Azores

    Directory of Open Access Journals (Sweden)

    J. M. Torta

    1997-06-01

    Full Text Available A local ground magnetic study of the Furnas caldera (S. Miguel Island, Azores has provided new insight into the magnetic structure of this volcano. Analysis of the data comprised removal of the IGRF, reduction to the pole, pseudogravity integration and upward continuation. Also, a spectral method was applied to estimate the depth to the magnetic sources, as well as a 2.5D forward modelling technique. Magnetic properties obtained at the laboratory for some representative sample rocks were considered in the modelling process. The most relevant features are the existence of an important negative anomaly inside the caldera and of an intense positive anomaly to the south of the coast. The former points out a decrease in the magnetization of the caldera filling materials with respect to the surrounding rocks, which could be explained as the result of post-eruption processes such as hydrothermal alteration. This is expected as Furnas has an active hydrothermal system probably related with a magmatic reservoir at high temperature. The positive anomaly suggests the existence of a strongly-magnetized body beneath the south coast.

  6. Structural controls on diffuse degassing in the Las Cañadas caldera, Tenerife, Canary Islands

    Science.gov (United States)

    Galindo, I.; Soriano, C.; Martí, J.; Pérez, N.

    2003-04-01

    The Las Cañadas caldera is an elliptical depression located in the central part of the Tenerife Island. The active Teide stratovolcano stands in the centre of the depression, which is limited to the south by the caldera wall, up to 500 m high above the caldera floor. Mapping most of the caldera wall at 1:5000 has provided new insights on its stratigraphy, structure, and geological evolution. Three major ENE-WSW normal faults have been mapped on the caldera wall in the area comprised between El Llano de Ucanca and Los Azulejos, where an intense hydrothermal alteration affects the lower stratigraphic levels of the caldera wall. Hydrothermal alteration is rather distinctive in this area, showing bluish to greenish colours. Most of the phonolitic cone sheets and radial dykes of the caldera wall do not show distinctive hydrothermal features, as do show the phonolitic pyroclastic rocks and lavas of the lower parts of the caldera wall. This suggests the main episodes of dyke intrusion in the Las Cañadas caldera postdate hydrothermal alteration. ENE-WSW normal faults involve dyke swarms and rocks of the upper stratigraphic levels of the caldera wall, and show displacements of up to 100 m. Unfortunately the upper possible age of these faults is poorly constrained since no contact relationship has been observed between fault planes and the rocks of the uppermost stratigraphic levels of the caldera wall. The rocks of the caldera wall adjacent to the faults are intensely fractured at the macro and mesoscale. In addition to field mapping, a soil gas survey was carried out at the caldera depression. Soil CO2 efflux and H2 concentration were measured reaching values of 12 gm-2d-1 and 4 ppmV, respectively. Spatial distribution of these species showed that positive anomalies coincide with the surface expression of the three major faults and their adjacent intensely fractured zone. The high CO2 and H2 values and their coincidence with major normal faults suggests that degassing in

  7. Influences of magma chamber ellipticity on ring fracturing and eruption at collapse calderas

    International Nuclear Information System (INIS)

    Holohan, Eoghan P; Walsh, John J; Vries, Benjamin van Wyk de; Troll, Valentin R; Walter, Thomas R

    2008-01-01

    Plan-view ellipticity of a pre-caldera magma reservoir, and its influence on the development of caldera ring fracturing and eruptive behaviour, have not previously been subjected to dedicated evaluation. We experimentally simulated caldera collapse into elliptical magma chambers and found that collapse into highly-elliptical chambers produced a characteristic pattern of ring-fault localization and lateral propagation. Although results are preliminary, the general deformation pattern for elliptical resurgence shows strong similarities to elliptical collapse. Ring faults accommodating uplift again initiate around the chamberos short axis and are reverse, but dip inward. Field and geophysical observations at several elliptical calderas of varying scale (e.g. Long Valley, Katmai, and Rabaul calderas) are consistent with a control from elliptical magma chamber geometry on ring fracturing and eruption, as predicted from our experiments.

  8. Influences of magma chamber ellipticity on ring fracturing and eruption at collapse calderas

    Energy Technology Data Exchange (ETDEWEB)

    Holohan, Eoghan P; Walsh, John J [Fault Analysis Group, School of Geological Sciences, University College Dublin, Belfield, Dublin 4 (Ireland); Vries, Benjamin van Wyk de [Laboratoire Magmas et Volcans, 5 rue Kessler, 63038 Clermont-Ferrand (France); Troll, Valentin R [Department of Earth Sciences, Uppsala University, SE-752 36, Uppsala (Sweden); Walter, Thomas R [GFZ Potsdam, Telegrafenberg, Potsdam, D-14473 (Germany)], E-mail: Eoghan.Holohan@ucd.ie

    2008-10-01

    Plan-view ellipticity of a pre-caldera magma reservoir, and its influence on the development of caldera ring fracturing and eruptive behaviour, have not previously been subjected to dedicated evaluation. We experimentally simulated caldera collapse into elliptical magma chambers and found that collapse into highly-elliptical chambers produced a characteristic pattern of ring-fault localization and lateral propagation. Although results are preliminary, the general deformation pattern for elliptical resurgence shows strong similarities to elliptical collapse. Ring faults accommodating uplift again initiate around the chamberos short axis and are reverse, but dip inward. Field and geophysical observations at several elliptical calderas of varying scale (e.g. Long Valley, Katmai, and Rabaul calderas) are consistent with a control from elliptical magma chamber geometry on ring fracturing and eruption, as predicted from our experiments.

  9. GPS time series at Campi Flegrei caldera (2000-2013

    Directory of Open Access Journals (Sweden)

    Prospero De Martino

    2014-05-01

    Full Text Available The Campi Flegrei caldera is an active volcanic system associated to a high volcanic risk, and represents a well known and peculiar example of ground deformations (bradyseism, characterized by intense uplift periods, followed by subsidence phases with some episodic superimposed mini-uplifts. Ground deformation is an important volcanic precursor, and, its continuous monitoring, is one of the main tool for short time forecast of eruptive activity. This paper provides an overview of the continuous GPS monitoring of the Campi Flegrei caldera from January 2000 to July 2013, including network operations, data recording and processing, and data products. In this period the GPS time series allowed continuous and accurate tracking of ground deformation of the area. Seven main uplift episodes were detected, and during each uplift period, the recurrent horizontal displacement pattern, radial from the “caldera center”, suggests no significant change in deformation source geometry and location occurs. The complete archive of GPS time series at Campi Flegrei area is reported in the Supplementary materials. These data can be usefull for the scientific community in improving the research on Campi Flegrei caldera dynamic and hazard assessment.

  10. Caldera deformation in Kyushu island (SW Japan) through InSAR data

    Science.gov (United States)

    Nobile, Adriano; Pepe, Susi; Ruch, Joel; Trippanera, Daniele; Casu, Francesco; Castaldo, Raffaele; Tizzani, Pietro; Aoki, Yosuke; Geshi, Nobuo; Acocella, Valerio; Sansosti, Eugenio; Siniscalchi, Valeria; Borgstrom, Sven; Zoffoli, Simona

    2014-05-01

    Calderas are the surface expression of a long-lived and complex magmatic system, often hosting a shallower hydrothermal system. Most monitored calderas have experienced some forms of unrest, even though only a part of these unrest episodes has culminated in an eruption. This study focuses on surface deformation analysis using InSAR from 1993 to 2013 at two large active calderas, Aso and Aira, located on Kyushu Island (Japan). Despite being closely monitored, our knowledge on the deformation history of both calderas with regard to their activity is poor. ERS, ENVISAT, ALOS and COSMO-SkyMed SAR images have been processed to obtain mean velocity deformation maps and time series through the SBAS technique. Results are then inverted using the simulated annealing technique to evaluate the deformation source parameters. Aso caldera hosts several vents in its central portion. One of these, the Naka Dake crater is the only currently active and erupted 7 times since 1993. From January 1996 to November 1998, after the important 1994 - 1995 eruption, we observed a subsidence of ~1.2 cm/yr at the center of the caldera. Analytical models suggest a deflating source (with various possible shapes) at 5-7 km of depth, implying a magmatic nature for the deformation. Inversion results are consistent with available seismic and GPS data. Aira Caldera hosts the Sakurajima volcano along its southern rim, with a persistent eruptive activity since 1950s. From June 2006 to March 2011, we observed a broad uplift of ~1.5 cm along most of the caldera rim. Analytical inversion of both the entire dataset and a cross-correlated dataset suggests a deformation source at the caldera center, at a depth of 5-9 km (depending on the source shape), implying a magmatic nature of the deformation. Inversion results are in agreement with GPS and InSAR data inversions for other periods of activity. This research has been partially performed within the frame of Italian Space Agency (ASI) and Japan Aerospace

  11. VALLE DE ABURRÁ: ¿QUO VADIS?

    Directory of Open Access Journals (Sweden)

    Hermelin Michel

    2008-07-01

    Full Text Available Se da una descripción somera de la evolución que ha tenido la prevención de los riesgos de origen natural en el Valle de Aburrá . Tanto la naturaleza litológica y estructural del valle como sus condiciones topográficas y climáticas lo hacen propenso a la ocurrencia de fenómenos naturales como sismos, movimientos de vertiente, avenidas torrenciales y, en menor grado, inundaciones. El aumento de la población que es actualmente de 3.5 millones de habitantes y la frecuente ocupación de lugares expuestos a amenazas han resultado en numerosos desastres. En este momento funcionan para la prevención y atención de desastres entidades como el SIMPAD y el DAPARD, con responsabilidades municipales y departamentales respectivamente. El grado de conocimiento del entorno físico del valle se considera insuficiente, así como las reglamentaciones que deberían tener como consecuencias de un uso de la tierra más acorde con las restricciones naturales. Se han realizado ya varias reuniones acerca de la gestión de riesgos naturales en la zona y los organizadores de la de 2007, que conmemora el vigésimo aniversario de la catástrofe de Villa Tina, pueden tomar la decisión de llevarlas a cabo cada dos años. Asimismo proponen la creación de un grupo técnicocientífico permanente dispuesto a estudiar los eventos ocurridos, a fomentar la difusión de la información pertinente y en general a propender por un mejor conocimiento del Valle de Aburrá.

  12. Scaling properties of planetary calderas and terrestrial volcanic eruptions

    Directory of Open Access Journals (Sweden)

    L. Sanchez

    2012-11-01

    Full Text Available Volcanism plays an important role in transporting internal heat of planetary bodies to their surface. Therefore, volcanoes are a manifestation of the planet's past and present internal dynamics. Volcanic eruptions as well as caldera forming processes are the direct manifestation of complex interactions between the rising magma and the surrounding host rock in the crust of terrestrial planetary bodies. Attempts have been made to compare volcanic landforms throughout the solar system. Different stochastic models have been proposed to describe the temporal sequences of eruptions on individual or groups of volcanoes. However, comprehensive understanding of the physical mechanisms responsible for volcano formation and eruption and more specifically caldera formation remains elusive. In this work, we propose a scaling law to quantify the distribution of caldera sizes on Earth, Mars, Venus, and Io, as well as the distribution of calderas on Earth depending on their surrounding crustal properties. We also apply the same scaling analysis to the distribution of interevent times between eruptions for volcanoes that have the largest eruptive history as well as groups of volcanoes on Earth. We find that when rescaled with their respective sample averages, the distributions considered show a similar functional form. This result implies that similar processes are responsible for caldera formation throughout the solar system and for different crustal settings on Earth. This result emphasizes the importance of comparative planetology to understand planetary volcanism. Similarly, the processes responsible for volcanic eruptions are independent of the type of volcanism or geographical location.

  13. Magma transfer at Campi Flegrei caldera (Italy) before the 1538 AD eruption

    Science.gov (United States)

    Di Vito, Mauro A.; Acocella, Valerio; Aiello, Giuseppe; Barra, Diana; Battaglia, Maurizio; Carandente, Antonio; Del Gaudio, Carlo; de Vita, Sandro; Ricciardi, Giovanni; Rico, Ciro; Scandone, Roberto; Terrasi, Filippo

    2017-04-01

    Defining and understanding the shallow transfer of magma at volcanoes is crucial to forecast eruptions, possibly the ultimate goal of volcanology. This is particularly challenging at felsic calderas experiencing unrest, which typically includes significant changes in seismicity, deformation and degassing rates. Caldera unrest is particularly frequent, affects wide areas and often does not culminate in an eruption. Moreover its evidence is usually complicated by the presence of a hydrothermal system. As a result, forecasting any eruption and vent-opening sites within a caldera is very difficult. The Campi Flegrei caldera (CFc), in the densely inhabited area of Naples (Italy), is commonly considered one of the most dangerous active volcanic systems. CFc is a 12 km wide depression hosting two nested calderas formed during the eruptions of the Campanian Ignimbrite ( 39 ka) and the Neapolitan Yellow Tuff ( 15 ka). In the last 5 ka, resurgence, with uplift >60 m close to the central part of the caldera, was accompanied by volcanism between 4.8 and 3.8 ka. After 3 ka of quiescence, increasing seismicity and uplift preceded the last eruption at Monte Nuovo in 1538 for several decades. The most recent activity culminated in four unrest episodes between 1950-1952, 1969-1972, 1982-1984 and 2005-Present, with a cumulative uplift at Pozzuoli of 4.5 m; the present unrest episode has been interpreted as being magma-driven. These unrest episodes are considered the most evident expression of a longer-term (centuries or more) restless activity. The post-1980 deformation largely results from a magmatic oblate or sill-like source at 4 km depth below Pozzuoli. Despite the restless activity of CFc, the recent unrest episodes did not culminate in eruption, so that any possibility to define the pre-eruptive shallow transfer of magma remains elusive. Indeed, this definition is a crucial step in order to identify and understand pre-eruptive processes, and thus to make any forecast. To fill

  14. el Valle del Cauca

    Directory of Open Access Journals (Sweden)

    Carlos Humberto Ortiz

    2007-01-01

    Full Text Available Este artículo se enfoca en la identi- ficación de aquellos factores estructurales que explican la pérdida de dinamismo económico de largo plazo en Colombia y, en particular, en el Valle del Cauca. Se examina la competitividad del Valle en relación con Colombia y con el resto del mundo. Se cuestiona la insistencia en una estrategia exportadora como dinamizadora del desarrollo económico. Se identifica que una gran parte de la población está excluida de los beneficios del desarrollo económico. Para construir un modelo de desarrollo que incluya a esta población se recomienda recuperar la senda de la industrialización, invertir en el capital humano (educación de alta calidad, salud, salubridad y nutrición, e invertir en infraestructura. La participación del Estado en estas inversiones sociales es necesaria para disminuir la desigualdad y aumentar el crecimiento económico.

  15. The caldera of Volcan Fernandina: a remote sensing study of its structure and recent activity

    Science.gov (United States)

    Rowland, Scott K.; Munro, Duncan C.

    1992-12-01

    Air photographs taken in 1946, 1960, and 1982, together with SPOT HVR-1 images obtained in April and October of 1988, are used to characterize recent activity in and around the caldera of Fernandina Volcano, West Galapagos Islands. The eruptive and collapse events during this time span appear to be distributed in a NW-SE band across the summit and caldera. On the flanks of the volcano, subtle topographic ridges indicate that this is a long-term preferred orientation of extra-caldera activity as well (although radial and arcuate fissures are found on all sectors). The caldera is formed from the coalescence of multiple collapse features that are also distributed along a NW-SE direction, and these give the caldera its elongate and scalloped outline. The NW and SE benches consist of lavas that ponded in once-separated depressions that have been incorporated into the caldera by more recent collapse. The volume of individual eruptions within the caldera over the observed 42 years appears to be small (˜4x106 m3) in comparison to the volumes of individual flows exposed in the caldera walls (˜120 150x106 m3). Field observations (in 1989) of lavas exposed in the caldera walls and their cross-cutting relationships show that there have been at least three generations of calderas, and that at times each was completely filled. An interplay between a varying supply rate to the volcano and a regional stress regime is suggested to be the cause of long-term spatial and volumetric variations in activity. When supply is high, the caldera is filled in relative to collapse and dikes tend to propagate in all directions through the edifice. At other times (such as the present) supply is relatively low; eruptions are small, the caldera is far from being filled in, and dike propagation is influenced by an extra-volcano stress regime.

  16. Carbonatite ring-complexes explained by caldera-style volcanism.

    Science.gov (United States)

    Andersson, Magnus; Malehmir, Alireza; Troll, Valentin R; Dehghannejad, Mahdieh; Juhlin, Christopher; Ask, Maria

    2013-01-01

    Carbonatites are rare, carbonate-rich magmatic rocks that make up a minute portion of the crust only, yet they are of great relevance for our understanding of crustal and mantle processes. Although they occur in all continents and from Archaean to present, the deeper plumbing system of carbonatite ring-complexes is usually poorly constrained. Here, we show that carbonatite ring-complexes can be explained by caldera-style volcanism. Our geophysical investigation of the Alnö carbonatite ring-complex in central Sweden identifies a solidified saucer-shaped magma chamber at ~3 km depth that links to surface exposures through a ring fault system. Caldera subsidence during final stages of activity caused carbonatite eruptions north of the main complex, providing the crucial element to connect plutonic and eruptive features of carbonatite magmatism. The way carbonatite magmas are stored, transported and erupt at the surface is thus comparable to known emplacement styles from silicic calderas.

  17. Gas Chemistry of Submarine Hydrothermal Venting at Maug Caldera, Mariana Arc

    Science.gov (United States)

    Embley, R. W.; Lupton, J. E.; Butterfield, D. A.; Lilley, M. D.; Evans, L. J.; Olson, E. J.; Resing, J. A.; Buck, N.; Larson, B. I.; Young, C.

    2014-12-01

    Maug volcano consists of 3 islands that define the perimeter of a submerged caldera that was formed by an explosive eruption. The caldera reaches a depth of ~225 meters, and has a prominent central cone or pinnacle that ascends within 20 meters of the sea surface. Our exploration of Maug began in 2003, when a single hydrocast in the caldera detected a strong suspended particle and helium plume reaching a maximum of δ3He = 250% at ~180 meters depth, clearly indicating hydrothermal activity within the caldera. In 2004 we returned armed with the ROPOS ROV, and two ROPOS dives discovered and sampled low temperature (~4 °C) diffuse venting associated with bacterial mats on the NE flank of the central pinnacle at 145 m depth. Samples collected with titanium gas tight bottles were badly diluted with ambient seawater but allowed an estimate of end-member 3He/4He of 7.3 Ra. Four vertical casts lowered into the caldera in 2004 all had a strong 3He signal (δ3He = 190%) at 150-190 meters depth. A recent expedition in 2014 focused on the shallow (~10 m) gas venting along the caldera interior. Scuba divers were able to collect samples of the gas bubbles using evacuated SS bottles fitted with plastic funnels. The gas samples had a consistent ~170 ppm He, 8 ppmNe, 60% CO2, 40%N2, and 0.8% Ar, and an end-member 3He/4He ratio of 6.9 Ra. This 3He/4He ratio falls within the range for typical arc volcanoes. The rather high atmospheric component (N2, Ar, Ne) in these samples is not contamination but appears to be derived from subsurface exchange between the ascending CO2 bubbles and air saturated seawater. A single vertical cast in 2014 had a maximum δ3He = 55% at 140 m depth, much lower than in 2003 and 2004. This decrease is possibly due to recent flushing of the caldera by a storm event, or may reflect a decrease in the deep hydrothermal activity. This area of shallow CO2 venting in Maug caldera is of particular interest as a natural laboratory for studying the effects of ocean

  18. Hydrothermal activity in the Tulancingo-Acoculco Caldera Complex, central Mexico. Exploratory studies

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Hernandez, Aida [Gerencia de Proyectos Geotermoelectricos, CFE, Alejandro Volta 655, 58290 Morelia, Michoacan (Mexico); Centro de Geociencias, Universidad Nacional Autonoma de Mexico, Campus Juriquilla, Queretaro, Qro., 76230 (Mexico); Garcia-Estrada, Gerardo; Palma-Guzman, Hugo; Quijano-Leon, Jose L. [Gerencia de Proyectos Geotermoelectricos, CFE, Alejandro Volta 655, 58290 Morelia, Michoacan (Mexico); Aguirre-Diaz, Gerardo; Gonzalez-Partida, Eduardo [Centro de Geociencias, Universidad Nacional Autonoma de Mexico, Campus Juriquilla, Queretaro, Qro., 76230 (Mexico)

    2009-09-15

    Mineral alteration and fluid inclusion studies of drill cuttings and core samples indicate that the sedimentary basement rocks and the volcanic rocks associated with Tulancingo-Acoculco Caldera Complex have been the site of two distinct and major hydrothermal events. The complex, located in the eastern portion of the Trans-Mexican Volcanic Belt, is formed by the Pliocene Tulancingo Caldera and the younger (Pleistocene) Acoculco Caldera, which developed within the older depression. The volcanic rocks are underlain by Cretaceous sedimentary rocks of the Sierra Madre Oriental. The earliest important hydrothermal event occurred during the emplacement of Mid-Tertiary granitic intrusions that metamorphosed the sedimentary rocks; these intrusives are not exposed at the surface. However, granitic rocks were encountered at the bottom of exploratory borehole EAC-1, drilled within the Caldera Complex. The second main event occurred during the formation of the Tulancingo and Acoculco Calderas. Both episodes lead to secondary mineralization that reduced the permeability of the reservoir rocks. A possible third hydrothermal event may be associated with the recent magmatic activity within the Acoculco Caldera.Thermal logs from well EAC-1 display a conductive thermal gradient with maximum temperatures exceeding 300 C at 2000 m depth. Although there are no active thermal springs in the area, there is extensive fossil surface hydrothermal alteration and cold gas discharges with high He{sup 3}/He{sup 4} ratios. (author)

  19. Cacilda Borges Do Valle

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics. Cacilda Borges Do Valle. Articles written in Journal of Genetics. Volume 83 Issue 3 December 2004 pp 279-283 Research Note. Abnormal pollen mitoses (PM I and PM II) in an interspecific hybrid of Brachiaria ruziziensis and Brachiaria decumbens (Gramineae) · Andréa Beatriz ...

  20. Insights into the emplacement of upper-crustal plutons and their relationship to large silicic calderas, from field relationships, geochronology, and zircon trace element geochemistry in the Stillwater - Clan Alpine caldera complex, western Nevada, USA

    Science.gov (United States)

    Colgan, Joseph P.; John, David A.; Henry, Christopher D.; Watts, Kathryn E.

    2018-01-01

    Geologic mapping, new U-Pb zircon ages, and new and published 40Ar/39Ar sanidine ages document the timing and extent of Oligocene magmatism in the southern Stillwater Range and Clan Alpine Mountains of western Nevada, where Miocene extension has exposed at least six nested silicic calderas and underlying granitic plutons to crustal depths locally ≥ 9 km. Both caldera-forming rhyolitic tuffs and underlying plutons were emplaced in two episodes, one from about 30.4-28.2 Ma that included the Deep Canyon, Job Canyon, and Campbell Creek calderas and underlying plutons, and one from about 25.3-24.8 Ma that included the Louderback Mountains, Poco Canyon, and Elevenmile Canyon calderas and underlying plutons. In these two 1-2 m.y. periods, almost the entire Mesozoic upper crust was replaced by Oligocene intrusive and extrusive rocks to depths ≥ 9 km over an estimated total area of 1500 km2 (pre-extension). Zircon trace element geochemistry indicates that some plutonic rock can be solidified residual magma from the tuff eruptions. Most plutons are not solidified residual magma, although they directly underlie calderas and were emplaced along the same structures shortly after to as much as one million years after caldera formation. Magma chambers and plutons grew by floor subsidence accommodated by downward transfer of country rocks. If other Great Basin calderas are similar, the dense concentration of shallowly exposed calderas in central Nevada is underlain by a complexly zoned mid-Cenozoic batholith assembled in discrete pulses that coincided with formation of large silicic calderas up to 2500-5000 km3.

  1. Graben calderas of the Sierra Madre Occidental: The case of Guanajuato, central Mexico

    Science.gov (United States)

    Aguirre-Diaz, G. J.; Tristán-González, M.; Labarthe-Hernández, G.; Marti, J.

    2013-12-01

    The Sierra Madre Occidental (SMO) volcanic province is characterized by voluminous silicic ignimbrites that reach an accumulated thickness of 500 to 1500 m. A single ignimbrite can reach up to 350 m thick in its outflow facies. This ignimbrite sequence formed mostly within 38-23 Ma, building up a total estimated volume of ca. 580,000 km3 making the SMO the largest ignimbrite province of the world. We have showed that several and probably most of the SMO ignimbrites were erupted from fissures associated to Basin and Range fault systems or grabens (Geology, 2003), thus naming these volcano-tectonic structures as graben calderas (Caldera Volcanism book, Elsevier, 2008). Generally, the sequence observed in graben calderas include, from oldest to youngest, alluvial fan deposits combined with lacustrine deposits, pyroclastic surge deposits and minor volume ignimbrites, a large-volume ignimbrite that could be massive or made of successive layers, and sometimes silicic lava domes and/or mafic fissural lavas both with vents aligned with the graben trend. Fallout deposits, plinian or non-plinian, are not observed in the sequence. Thus, onset of caldera collapse represented by the major ignimbrite must occur just after deposition of continental sediments within the graben domain. A similar volcano-tectonic development is observed in pull-apart grabens. Therefore, extensional or transtensional tectonics, before and during caldera collapse, and the emplacement of a subgraben shallow silicic magma chamber are the necessary conditions for the development of graben calderas. We describe here the case of the Guanajuato graben caldera, located in the central part of Mexico and in the southeastern portion of the SMO volcanic province. The caldera is part of the economically important mining district of Guanajuato, with 28 silver mines, some active since the 16th century. The caldera structure, a rectangle of 10 x 16 km, was controlled by NW and NE regional fault systems. Most ore

  2. Long Valley Caldera-Mammoth Mountain unrest: The knowns and unknowns

    Science.gov (United States)

    Hill, David P.

    2017-01-01

    This perspective is based largely on my study of the Long Valley Caldera (California, USA) over the past 40 years. Here, I’ll examine the “knowns” and the “known unknowns” of the complex tectonic–magmatic system of the Long Valley Caldera volcanic complex. I will also offer a few brief thoughts on the “unknown unknowns” of this system.

  3. The confirmation of a work hypothesis: a new caldera in the center of the Mexican Volcanic Belt; La confirmacion de una hipotesis de trabajo: una nueva caldera en el centro del Cinturon Volcanico Mexicano

    Energy Technology Data Exchange (ETDEWEB)

    Anguita Virella, Francisco; Pal Verma, Surendra; Milan, Marcos; Garcia Cacho, Luis; Samaniego M, Daniel [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1991-12-31

    After synthesizing the most relevant aspects of the current volcanology and the genesis process of the collapse calderas, a process is described on the location and confirmation of a new caldera (the Mazahua) in the central part of the Mexican Volcanic Belt (MVB). [Espanol] Tras sintetizar los aspectos mas destacados de la vulcanologia actual y el proceso de genesis de las calderas de colapso, se describe el proceso de localizacion y confirmacion de una nueva caldera (la Mazahua) en la parte central del Cinturon Volcanico Mexicano (CVM).

  4. The confirmation of a work hypothesis: a new caldera in the center of the Mexican Volcanic Belt; La confirmacion de una hipotesis de trabajo: una nueva caldera en el centro del Cinturon Volcanico Mexicano

    Energy Technology Data Exchange (ETDEWEB)

    Anguita Virella, Francisco; Pal Verma, Surendra; Milan, Marcos; Garcia Cacho, Luis; Samaniego M, Daniel [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1992-12-31

    After synthesizing the most relevant aspects of the current volcanology and the genesis process of the collapse calderas, a process is described on the location and confirmation of a new caldera (the Mazahua) in the central part of the Mexican Volcanic Belt (MVB). [Espanol] Tras sintetizar los aspectos mas destacados de la vulcanologia actual y el proceso de genesis de las calderas de colapso, se describe el proceso de localizacion y confirmacion de una nueva caldera (la Mazahua) en la parte central del Cinturon Volcanico Mexicano (CVM).

  5. Is there a geochemical link between volcanic and plutonic rocks in the Organ Mountains caldera?

    Science.gov (United States)

    Memeti, V.; Davidson, J.

    2013-12-01

    determine within-crystal geochemical variations. Our current conclusions and working hypotheses are: 1) All igneous rocks from the Organ Mountains are crustal-mantle melt mixtures indicating two component mixing; 2) the caldera-forming ignimbrites are likely derived from a fractionating Organ Needle pluton; 3) pre- and post-caldera lavas are isotopically similar to the post-caldera Sugarloaf Peak quartz-monzonite; 4) K-feldspar cumulate textures in the structurally top 0.5-1 km of the Organ Needle pluton indicate that interstitial melt was lost from the magma mush, which likely fed the ignimbrite eruptions. 5) Plutonic feldspar textures are complex compared to rather simple zoned volcanic feldspars including K-feldspar rimmed plagioclase, plagioclase rimmed K-feldspar and unrimmed feldspars occurring over a range of grain sizes at thin section scale. Some volcanic feldspar phenocrysts have any previous zonation erased due to late stage albitization. Although the single mineral studies are still work in progress and details need resolving, our data so far suggest a geochemical link between volcanic and plutonic rocks of the Organ Mountains caldera, albeit a complex one; and greater complexity in plutonic versus volcanic minerals. [1] Seager (1980), NM Bureau of Mines and Min. Res. Memoir 36, 97 p. [2] Zimmerer & McIntosh (2013) Journal of Geophysical Research, v. 93, p. 4421-4433

  6. Is Kasei Valles (Mars) the largest volcanic channel in the solar system?

    Science.gov (United States)

    Leverington, David W.

    2018-02-01

    With a length of more than 2000 km and widths of up to several hundred kilometers, Kasei Valles is the largest outflow system on Mars. Superficially, the scabland-like character of Kasei Valles is evocative of terrestrial systems carved by catastrophic aqueous floods, and the system is widely interpreted as a product of outbursts from aquifers. However, as at other Martian outflow channels, clear examples of fluvial sedimentary deposits have proven difficult to identify here. Though Kasei Valles lacks several key properties expected of aqueous systems, its basic morphological and contextual properties are aligned with those of ancient volcanic channels on Venus, the Moon, Mercury, and Earth. There is abundant evidence that voluminous effusions of low-viscosity magmas occurred at the head of Kasei Valles, the channel system acted as a conduit for associated flows, and mare-style volcanic plains developed within its terminal basin. Combined mechanical and thermal incision rates of at least several meters per day are estimated to have been readily achieved at Kasei Valles by 20-m-deep magmas flowing with viscosities of 1 Pa s across low topographic slopes underlain by bedrock. If Kasei Valles formed through incision by magma, it would be the largest known volcanic channel in the solar system. The total volume of magma erupted at Kasei Valles is estimated here to have possibly reached or exceeded ∼5 × 106 km3, a volume comparable in magnitude to those that characterize individual Large Igneous Provinces on Earth. Development of other large outflow systems on Mars is expected to have similarly involved eruption of up to millions of cubic kilometers of magma.

  7. Insights into the emplacement of upper-crustal plutons and their relationship to large silicic calderas, from field relationships, geochronology, and zircon trace element geochemistry in the Stillwater – Clan Alpine caldera complex, western Nevada, USA

    Science.gov (United States)

    Colgan, Joseph P.; John, David A.; Henry, Christopher D.; Watts, Kathryn E.

    2018-01-01

    Geologic mapping, new U-Pb zircon ages, and new and published 40Ar/39Ar sanidine ages document the timing and extent of Oligocene magmatism in the southern Stillwater Range and Clan Alpine Mountains of western Nevada, where Miocene extension has exposed at least six nested silicic calderas and underlying granitic plutons to crustal depths locally ≥ 9 km. Both caldera-forming rhyolitic tuffs and underlying plutons were emplaced in two episodes, one from about 30.4–28.2 Ma that included the Deep Canyon, Job Canyon, and Campbell Creek calderas and underlying plutons, and one from about 25.3–24.8 Ma that included the Louderback Mountains, Poco Canyon, and Elevenmile Canyon calderas and underlying plutons. In these two 1–2 m.y. periods, almost the entire Mesozoic upper crust was replaced by Oligocene intrusive and extrusive rocks to depths ≥ 9 km over an estimated total area of ~ 1500 km2 (pre-extension). Zircon trace element geochemistry indicates that some plutonic rock can be solidified residual magma from the tuff eruptions. Most plutons are not solidified residual magma, although they directly underlie calderas and were emplaced along the same structures shortly after to as much as one million years after caldera formation. Magma chambers and plutons grew by floor subsidence accommodated by downward transfer of country rocks. If other Great Basin calderas are similar, the dense concentration of shallowly exposed calderas in central Nevada is underlain by a complexly zoned mid-Cenozoic batholith assembled in discrete pulses that coincided with formation of large silicic calderas up to 2500–5000 km3.

  8. Giant caldera in the Arctic Ocean: Evidence of the catastrophic eruptive event.

    Science.gov (United States)

    Piskarev, Alexey; Elkina, Daria

    2017-04-10

    A giant caldera located in the eastern segment of the Gakkel Ridge could be firstly seen on the bathymetric map of the Arctic Ocean published in 1999. In 2014, seismic and multibeam echosounding data were acquired at the location. The caldera is 80 km long, 40 km wide and 1.2 km deep. The total volume of ejected volcanic material is estimated as no less than 3000 km 3 placing it into the same category with the largest Quaternary calderas (Yellowstone and Toba). Time of the eruption is estimated as ~1.1 Ma. Thin layers of the volcanic material related to the eruption had been identified in sedimentary cores located about 1000 km away from the Gakkel Ridge. The Gakkel Ridge Caldera is the single example of a supervolcano in the rift zone of the Mid-Oceanic Ridge System.

  9. Uplift, thermal unrest and magma intrusion at Yellowstone caldera.

    Science.gov (United States)

    Wicks, Charles W; Thatcher, Wayne; Dzurisin, Daniel; Svarc, Jerry

    2006-03-02

    The Yellowstone caldera, in the western United States, formed approximately 640,000 years ago when an explosive eruption ejected approximately 1,000 km3 of material. It is the youngest of a series of large calderas that formed during sequential cataclysmic eruptions that began approximately 16 million years ago in eastern Oregon and northern Nevada. The Yellowstone caldera was largely buried by rhyolite lava flows during eruptions that occurred from approximately 150,000 to approximately 70,000 years ago. Since the last eruption, Yellowstone has remained restless, with high seismicity, continuing uplift/subsidence episodes with movements of approximately 70 cm historically to several metres since the Pleistocene epoch, and intense hydrothermal activity. Here we present observations of a new mode of surface deformation in Yellowstone, based on radar interferometry observations from the European Space Agency ERS-2 satellite. We infer that the observed pattern of uplift and subsidence results from variations in the movement of molten basalt into and out of the Yellowstone volcanic system.

  10. Long Valley Caldera 2003 through 2014: overview of low level unrest in the past decade

    Science.gov (United States)

    Wilkinson, Stuart K.; Hill, David P.; Langbein, John O.; Lisowski, Michael; Mangan, Margaret T.

    2014-01-01

    Long Valley Caldera is located in California along the eastern escarpment of the Sierra Nevada Range. The caldera formed about 760,000 years ago as the eruption of 600 km3 of rhyolite magma (Bishop Tuff) resulted in collapse of the partially evacuated magma chamber. Resurgent doming in the central part of the caldera occurred shortly afterwards, and the most recent eruptions inside the caldera occurred about 50,000 years ago. The caldera remains thermally active, with many hot springs and fumaroles, and has had significant deformation and seismicity since at least 1978. Periods of intense unrest in the 1980s to early 2000s are well documented in the literature (Hill and others, 2002; Ewert and others, 2010). In this poster, we extend the timeline forward, documenting seismicity and deformation over the past decade.

  11. Valle del Chota: fútbol, identidad y mercado

    OpenAIRE

    Ortiz Villalva, Verónica

    2011-01-01

    Al fútbol se le ha conferido varios sentidos y valor social: juego, deporte, ritual, opio, espectáculo, negocio, etc. Cada faceta responde a la apropiación que los grupos sociales han hecho de este deporte. En este sentido, podríamos decir que el fútbol también significa movilidad socioeconómica, inclusión real y simbólica, reconocimiento y visibilización, al menos, para el Valle del Chota. El Valle del Chota, conocido como la cantera de los mejores futbolistas del país, es ...

  12. Maars to calderas: end-members on a spectrum of explosive volcanic depressions

    Directory of Open Access Journals (Sweden)

    Danilo M. Palladino

    2015-07-01

    Full Text Available We discuss maar-diatremes and calderas as end-members on a spectrum of negative volcanic landforms (depressions produced by explosive eruptions (note – we focus on calderas formed during explosive eruptions, recognizing that some caldera types are not related to such activity. The former are dominated by ejection of material during numerous discrete phreatomagmatic explosions, brecciation, and subsidence of diatreme fill, while the latter are dominated by subsidence over a partly evacuated magma chamber during sustained, magmatic volatile-driven discharge. Many examples share characteristics of both, including landforms that are identified as maars but preserve deposits from non-phreatomagmatic explosive activity, and ambiguous structures that appear to be coalesced maars but that also produced sustained explosive eruptions with likely magma reservoir subsidence. A convergence of research directions on issues related to magma-water interaction and shallow reservoir mechanics is an important avenue toward developing a unified picture of the maar-diatreme-caldera spectrum.

  13. Los tambos Inca: el caso de Camata Tambo valle alto de Moquegua

    OpenAIRE

    Chacaltana Cortez, Sofía; Ministerio de Cultura

    2013-01-01

    Camata Tambo está ubicado en la parte alta del valle alto de Moquegua. Por este tambo pasa un camino Inca que viene del altiplano y continúa hacia el centro provincial de Sabaya ubicado a 1 km valle abajo.

  14. Long Valley caldera and the UCERF depiction of Sierra Nevada range-front faults

    Science.gov (United States)

    Hill, David P.; Montgomery-Brown, Emily K.

    2015-01-01

    Long Valley caldera lies within a left-stepping offset in the north-northwest-striking Sierra Nevada range-front normal faults with the Hilton Creek fault to the south and Hartley Springs fault to the north. Both Uniform California Earthquake Rupture Forecast (UCERF) 2 and its update, UCERF3, depict slip on these major range-front normal faults as extending well into the caldera, with significant normal slip on overlapping, subparallel segments separated by ∼10  km. This depiction is countered by (1) geologic evidence that normal faulting within the caldera consists of a series of graben structures associated with postcaldera magmatism (intrusion and tumescence) and not systematic down-to-the-east displacements consistent with distributed range-front faulting and (2) the lack of kinematic evidence for an evolving, postcaldera relay ramp structure between overlapping strands of the two range-front normal faults. The modifications to the UCERF depiction described here reduce the predicted shaking intensity within the caldera, and they are in accord with the tectonic influence that underlapped offset range-front faults have on seismicity patterns within the caldera associated with ongoing volcanic unrest.

  15. The Acoculco caldera magmas: genesis, evolution and relation with the Acoculco geothermal system

    Science.gov (United States)

    Sosa-Ceballos, G.; Macías, J. L.; Avellán, D.

    2017-12-01

    The Acoculco Caldera Complex (ACC) is located at the eastern part of the Trans Mexican Volcanic Belt; México. This caldera complex have been active since 2.7 Ma through reactivations of the system or associated magmatism. Therefore the ACC is an excellent case scenario to investigate the relation between the magmatic heat supply and the evolution processes that modified magmatic reservoirs in a potential geothermal field. We investigated the origin and the magmatic processes (magma mixing, assimilation and crystallization) that modified the ACC rocks by petrography, major oxides-trace element geochemistry, and isotopic analysis. Magma mixing is considered as the heat supply that maintain active the magmatic system, whereas assimilation yielded insights about the depth at which processes occurred. In addition, we performed a series of hydrothermal experiments in order to constrain the storage depth for the magma tapped during the caldera collapse. Rocks from the ACC were catalogued as pre, syn and post caldera. The post caldera rocks are peralkaline rhyolites, in contrast to all other rocks that are subalkaline. Our investigation is focus to investigate if the collapse modified the plumbing system and the depth at which magmas stagnate and recorded the magmatic processes.

  16. Physical volcanology of the mafic segment of the subaqueous New Senator caldera, Abitibi greenstone belt, Quebec, Canada

    International Nuclear Information System (INIS)

    Moore, Lyndsay N; Mueller, Wulf U

    2008-01-01

    Archean calderas provide valuable insight into internal geometries of subaqueous calderas. The New Senator caldera, Abitibi greenstone belt, Canada, is an Archean example of a subaqueous nested caldera with a basal stratigraphy dominated by gabbro-diorite dykes and sills, ponded magmas and basalt and andesite lava flows. The aim of our study is to focus on the use of physical volcanology to differentiate between the various mafic units found at the base of the New Senator caldera. Differentiation between these various mafic units is important from an exploration point of view because in modern subaqueous summit calders (e.g. Axial Seamount) margins of ponded magmas are often sites of VMS formation.

  17. Physical volcanology of the mafic segment of the subaqueous New Senator caldera, Abitibi greenstone belt, Quebec, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Lyndsay N; Mueller, Wulf U [Universite du Quebec a Chicoutimi, 555 boul. du l' Universite, Chicoutimi, Quebec, G7H2B1 (Canada)], E-mail: lyndsay.moore@uqac.ca

    2008-10-01

    Archean calderas provide valuable insight into internal geometries of subaqueous calderas. The New Senator caldera, Abitibi greenstone belt, Canada, is an Archean example of a subaqueous nested caldera with a basal stratigraphy dominated by gabbro-diorite dykes and sills, ponded magmas and basalt and andesite lava flows. The aim of our study is to focus on the use of physical volcanology to differentiate between the various mafic units found at the base of the New Senator caldera. Differentiation between these various mafic units is important from an exploration point of view because in modern subaqueous summit calders (e.g. Axial Seamount) margins of ponded magmas are often sites of VMS formation.

  18. Maja Valles, Mars: A Multi-Source Fluvio-Volcanic Outflow Channel System

    Science.gov (United States)

    Keske, A.; Christensen, P. R.

    2017-12-01

    The resemblance of martian outflow channels to the channeled scablands of the Pacific Northwest has led to general consensus that they were eroded by large-scale flooding. However, the observation that many of these channels are coated in lava issuing from the same source as the water source has motivated the alternative hypothesis that the channels were carved by fluid, turbulent lava. Maja Valles is a circum-Chryse outflow channel whose origin was placed in the late Hesperian by Baker and Kochel (1979), with more recent studies of crater density variations suggesting that its formation history involved multiple resurfacing events (Chapman et al., 2003). In this study, we have found that while Maja Valles indeed host a suite of standard fluvial landforms, its northern portion is thinly coated with lava that has buried much of the older channel landforms and overprinted them with effusive flow features, such as polygons and bathtub rings. Adjacent to crater pedestals and streamlined islands are patches of dark, relatively pristine material pooled in local topographic lows that we have interpreted as ponds of lava remaining from one or more fluid lava flows that flooded the channel system and subsequently drained, leaving marks of the local lava high stand. Despite the presence of fluvial landforms throughout the valles, lava flow features exist in the northern reaches of the system alone, 500-1200 km from the channels' source. The flows can instead be traced to a collection of vents in Lunae Plaum, west of the valles. In previously studied fluvio-volcanic outflow systems, such as Athabasca Valles, the sources of the volcanic activity and fluvial activity have been indistinguishable. In contrast, Maja Valles features numerous fluvio-volcanic landforms bearing similarity to those identified in other channel systems, yet the source of its lava flows is distinct from the source of its channels. Furthermore, in the absence of any channels between the source of the lava

  19. A Sr-isotopic comparison between thermal waters, rocks, and hydrothermal calcites, Long Valley caldera, California

    Science.gov (United States)

    Goff, F.; Wollenberg, H.A.; Brookins, D.C.; Kistler, R.W.

    1991-01-01

    The 87Sr/86Sr values of thermal waters and hydrothermal calcites of the Long Valley caldera geothermal system are more radiogenic than those of young intracaldera volcanic rocks. Five thermal waters display 87Sr/86Sr of 0.7081-0.7078 but show systematically lighter values from west to east in the direction of lateral flow. We believe the decrease in ratio from west to east signifies increased interaction of deeply circulating thermal water with relatively fresh volcanic rocks filling the caldera depression. All types of pre-, syn-, and post-caldera volcanic rocks in the west and central caldera have (87Sr/86Sr)m between about 0.7060 and 0.7072 and values for Sierra Nevada granodiorites adjacent to the caldera are similar. Sierran pre-intrusive metavolcanic and metasedimentary rocks can have considerably higher Sr-isotope ratios (0.7061-0.7246 and 0.7090-0.7250, respectively). Hydrothermally altered volcanic rocks inside the caldera have (87Sr/86Sr)m slightly heavier than their fresh volcanic equivalents and hydrothermal calcites (0.7068-0.7105) occupy a midrange of values between the volcanic/plutonic rocks and the Sierran metamorphic rocks. These data indicate that the Long Valley geothermal reservoir is first equilibrated in a basement complex that contains at least some metasedimentary rocks. Reequilibration of Sr-isotope ratios to lower values occurs in thermal waters as convecting geothermal fluids flow through the isotopically lighter volcanic rocks of the caldera fill. ?? 1991.

  20. Caldera unrest detected with seawater temperature anomalies at Deception Island, Antarctic Peninsula

    Science.gov (United States)

    Berrocoso, M.; Prates, G.; Fernández-Ros, A.; Peci, L. M.; de Gil, A.; Rosado, B.; Páez, R.; Jigena, B.

    2018-04-01

    Increased thermal activity was detected to coincide with the onset of volcano inflation in the seawater-filled caldera at Deception Island. This thermal activity was manifested in pulses of high water temperature that coincided with ocean tide cycles. The seawater temperature anomalies were detected by a thermometric sensor attached to the tide gauge (bottom pressure sensor). This was installed where the seawater circulation and the locations of known thermal anomalies, fumaroles and thermal springs, together favor the detection of water warmed within the caldera. Detection of the increased thermal activity was also possible because sea ice, which covers the entire caldera during the austral winter months, insulates the water and thus reduces temperature exchange between seawater and atmosphere. In these conditions, the water temperature data has been shown to provide significant information about Deception volcano activity. The detected seawater temperature increase, also observed in soil temperature readings, suggests rapid and near-simultaneous increase in geothermal activity with onset of caldera inflation and an increased number of seismic events observed in the following austral summer.

  1. Two-phase, reciprocal, double trapdoor collapse at Hannegan caldera, North Cascades, Washington, USA

    Energy Technology Data Exchange (ETDEWEB)

    Tucker, David S [Mount Baker Volcano Research Center Geology Department Western Washington University 516 High Street Bellingham, Washington 98225-9080 (United States)], E-mail: DaveTucker@mbvo.wwu.edu

    2008-10-01

    The intracaldera Hannegan volcanics were erupted during two collapse episodes of the Hannegan caldera in the North Cascade mountains of Washington State. The first eruption yielded a down-to-the-north trapdoor style collapse at 3.722 {+-} 0.020 Ma (40Ar/39Ar) that is bounded by a horseshoe-shaped ring fault. The second collapse, most probably also trapdoor style, followed a short period of sedimentation, and completed the elliptical ring fault around the southern margin of the caldera. Post caldera plutons, with U-Pb ages of 3.42 {+-} 0.10 and 3.36 {+-} 0.20 Ma, intruded the intracaldera ignimbrite.

  2. Active deformation in the northern Sierra de Valle Fértil, Sierras Pampeanas, Argentina

    Science.gov (United States)

    Ortiz, Gustavo; Alvarado, Patricia; Fosdick, Julie C.; Perucca, Laura; Saez, Mauro; Venerdini, Agostina

    2015-12-01

    The Western Sierras Pampeanas region in the San Juan Province is characterized by thick-skinned deformation with approximately N-S trending ranges of average heights of 2500 m and a high frequency occurrence of seismic activity. Its location to the east of the mainly thin-skinned tectonics of the Argentine Precordillera fold-and-thrust belt suggests that at 30°S, deformation is concentrated in a narrow zone involving these two morphostructural units. In this paper, we present new apatite (U-Th)/He results (AHe) across the northern part of the Sierra de Valle Fértil (around 30°S) and analyze them in a framework of thermochronologic available datasets. We found Pliocene AHe results for Carboniferous and Triassic strata in the northern Sierra de Valle Fértil consistent with the hypothesis of recent cooling and inferred erosional denudation concentrated along the northern end of this mountain range. Our analysis shows that this northern region may have evolved under different conditions than the central part of the Sierra de Valle Fértil. Previous studies have observed AHe ages consistent with Permian through Cretaceous cooling, indicating the middle part of the Sierra de Valle Fértil remained near surface before the Pampean slab subduction flattening process. Those studies also obtained ˜5 My cooling ages in the southern part of the Sierra de Valle Fértil, which are similar to our results in the northern end of the range. Taken together, these results suggest a pattern of young deformation in the northern and southern low elevation ends of the Sierra de Valle Fértil consistent with regions of high seismic activity, and Quaternary active faulting along the western-bounding thrust fault of the Sierra de Valle Fértil.

  3. Steady subsidence of a repeatedly erupting caldera through InSAR observations: Aso, Japan

    KAUST Repository

    Nobile, Adriano

    2017-04-05

    The relation between unrest and eruption at calderas is still poorly understood. Aso caldera, Japan, shows minor episodic phreatomagmatic eruptions associated with steady subsidence. We analyse the deformation of Aso using SAR images from 1993 to 2011 and compare it with the eruptive activity. Although the dataset suffers from limitations (e.g. atmospheric effects, coherence loss, low signal-to-noise ratio), we observe a steady subsidence signal from 1996 to 1998, which suggests an overall contraction of a magmatic source below the caldera centre, from 4 to 5 km depth. We propose that the observed contraction may have been induced by the release of the magmatic fluids feeding the eruptions. If confirmed by further data, this hypothesis suggests that degassing processes play a crucial role in triggering minor eruptions within open conduit calderas, such as at Aso. Our study underlines the importance of defining any eruptive potential also from deflating magmatic systems with open conduit.

  4. Doubly stochastic models for volcanic hazard assessment at Campi Flegrei caldera

    CERN Document Server

    Bevilacqua, Andrea

    2016-01-01

    This study provides innovative mathematical models for assessing the eruption probability and associated volcanic hazards, and applies them to the Campi Flegrei caldera in Italy. Throughout the book, significant attention is devoted to quantifying the sources of uncertainty affecting the forecast estimates. The Campi Flegrei caldera is certainly one of the world’s highest-risk volcanoes, with more than 70 eruptions over the last 15,000 years, prevalently explosive ones of varying magnitude, intensity and vent location. In the second half of the twentieth century the volcano apparently once again entered a phase of unrest that continues to the present. Hundreds of thousands of people live inside the caldera and over a million more in the nearby city of Naples, making a future eruption of Campi Flegrei an event with potentially catastrophic consequences at the national and European levels.

  5. CARACTERIZACIÓN COLORIMÉTRICA DEL MANJAR BLANCO DEL VALLE CARACTERIZAÇÃO COLORIMÉTRICA DE MANJAR BRANCO DEL VALLE COLORIMETRIC CHARACTERIZATION OF MANJAR BLANCO DEL VALLE

    Directory of Open Access Journals (Sweden)

    DIEGO FABIÁN NOVOA

    2012-12-01

    Full Text Available El Manjar Blanco del Valle originario de la región del Valle del Cauca en Colombia es considerado como símbolo gastronómico y cultural; es un tipo de dulce de leche con adición de almidón. El color es uno de los atributos más importantes en los alimentos. La medición del color tiene aplicaciones en el control de calidad y el desarrollo de nuevos productos. En esta investigación se caracteriza el color instrumental (escala CIE-L*a*b* del manjar blanco del Valle elaborado por empresas representativas y tradicionales de la región, mediante la determinación de los parámetros de color (L*, a*, b* de tres lotes de cada una de las marcas comerciales. También se caracterizó físicamente las muestras, encontrando pH entre 5,73 y 6,02 y grados Brix entre 65,16 y 76,47. Los valores promedio de los parámetros de color determinados experimentalmente para el manjar blanco fueron: L* 43,60, a* 14,58 y b* 34,67. De los datos reportados en este trabajo se concluye que existe una variabilidad considerable en el color entre lotes y marcas comerciales, lo que evidencia la necesidad de establecer procedimientos de estandarización en la producción y en la materia prima, con el fin de lograr un producto con características similares.O Manjar Branco Del Valle originário da região do Vale de Cauca na Colômbia é considerado um símbolo gastronômico e cultural; é um tipo de doce de leite com adição de amido. A coloração é um dos atributos mais importantes nos alimentos. A determinação da cor tem aplicações no controle de qualidade e no desenvolvimento de novos produtos. Neste estudo se caracterizou a cor instrumental (Sistema CIE-L*a*b* do Manjar Branco Del Valle produzido por empresas representativas e tradicionais da região, mediante a determinação dos parâmetros de cor (L*, a*, b* de três lotes de cada uma das marcas comerciais. Também se caracterizou fisicamente as amostras, encontrando pH entre 5,73 e 6,02 e graus Brix entre 65

  6. Ground Deformation Related to Caldera Collapse and Ring-Fault Activity

    KAUST Repository

    Liu, Yuan-Kai

    2018-05-01

    Volcanic subsidence, caused by partial emptying of magma in the subsurface reservoir has long been observed by spaceborne radar interferometry. Monitoring long-term crustal deformation at the most notable type of volcanic subsidence, caldera, gives us insights of the spatial and hazard-related information of subsurface reservoir. Several subsiding calderas, such as volcanoes on the Galapagos islands have shown a complex ground deformation pattern, which is often composed of a broad deflation signal affecting the entire edifice and a localized subsidence signal focused within the caldera floor. Although numerical or analytical models with multiple reservoirs are proposed as the interpretation, geologically and geophysically evidenced ring structures in the subsurface are often ignored. Therefore, it is still debatable how deep mechanisms relate to the observed deformation patterns near the surface. We aim to understand what kind of activities can lead to the complex deformation. Using two complementary approaches, we study the three-dimensional geometry and kinematics of deflation processes evolving from initial subsidence to later collapse of calderas. Firstly, the analog experiments analyzed by structure-from-motion photogrammetry (SfM) and particle image velocimetry (PIV) helps us to relate the surface deformation to the in-depth structures. Secondly, the numerical modeling using boundary element method (BEM) simulates the characteristic deformation patterns caused by a sill-like source and a ring-fault. Our results show that the volcano-wide broad deflation is primarily caused by the emptying of the deep magma reservoir, whereas the localized deformation on the caldera floor is related to ring-faulting at a shallower depth. The architecture of the ring-fault to a large extent determines the deformation localization on the surface. Since series evidence for ring-faulting at several volcanoes are provided, we highlight that it is vital to include ring

  7. Ground Deformation Related to Caldera Collapse and Ring-Fault Activity

    KAUST Repository

    Liu, Yuan-Kai

    2018-01-01

    Volcanic subsidence, caused by partial emptying of magma in the subsurface reservoir has long been observed by spaceborne radar interferometry. Monitoring long-term crustal deformation at the most notable type of volcanic subsidence, caldera, gives us insights of the spatial and hazard-related information of subsurface reservoir. Several subsiding calderas, such as volcanoes on the Galapagos islands have shown a complex ground deformation pattern, which is often composed of a broad deflation signal affecting the entire edifice and a localized subsidence signal focused within the caldera floor. Although numerical or analytical models with multiple reservoirs are proposed as the interpretation, geologically and geophysically evidenced ring structures in the subsurface are often ignored. Therefore, it is still debatable how deep mechanisms relate to the observed deformation patterns near the surface. We aim to understand what kind of activities can lead to the complex deformation. Using two complementary approaches, we study the three-dimensional geometry and kinematics of deflation processes evolving from initial subsidence to later collapse of calderas. Firstly, the analog experiments analyzed by structure-from-motion photogrammetry (SfM) and particle image velocimetry (PIV) helps us to relate the surface deformation to the in-depth structures. Secondly, the numerical modeling using boundary element method (BEM) simulates the characteristic deformation patterns caused by a sill-like source and a ring-fault. Our results show that the volcano-wide broad deflation is primarily caused by the emptying of the deep magma reservoir, whereas the localized deformation on the caldera floor is related to ring-faulting at a shallower depth. The architecture of the ring-fault to a large extent determines the deformation localization on the surface. Since series evidence for ring-faulting at several volcanoes are provided, we highlight that it is vital to include ring

  8. Magmatism, ash-flow tuffs, and calderas of the ignimbrite flareup in the western Nevada volcanic field, Great Basin, USA

    Science.gov (United States)

    Christopher D. Henry,; John, David A.

    2013-01-01

    The western Nevada volcanic field is the western third of a belt of calderas through Nevada and western Utah. Twenty-three calderas and their caldera-forming tuffs are reasonably well identified in the western Nevada volcanic field, and the presence of at least another 14 areally extensive, apparently voluminous ash-flow tuffs whose sources are unknown suggests a similar number of undiscovered calderas. Eruption and caldera collapse occurred between at least 34.4 and 23.3 Ma and clustered into five ∼0.5–2.7-Ma-long episodes separated by quiescent periods of ∼1.4 Ma. One eruption and caldera collapse occurred at 19.5 Ma. Intermediate to silicic lavas or shallow intrusions commonly preceded caldera-forming eruptions by 1–6 Ma in any specific area. Caldera-related as well as other magmatism migrated from northeast Nevada to the southwest through time, probably resulting from rollback of the formerly shallow-dipping Farallon slab. Calderas are restricted to the area northeast of what was to become the Walker Lane, although intermediate and effusive magmatism continued to migrate to the southwest across the future Walker Lane.Most ash-flow tuffs in the western Nevada volcanic field are rhyolites, with approximately equal numbers of sparsely porphyritic (≤15% phenocrysts) and abundantly porphyritic (∼20–50% phenocrysts) tuffs. Both sparsely and abundantly porphyritic rhyolites commonly show compositional or petrographic evidence of zoning to trachydacites or dacites. At least four tuffs have volumes greater than 1000 km3, with one possibly as much as ∼3000 km3. However, the volumes of most tuffs are difficult to estimate, because many tuffs primarily filled their source calderas and/or flowed and were deposited in paleovalleys, and thus are irregularly distributed.Channelization and westward flow of most tuffs in paleovalleys allowed them to travel great distances, many as much as ∼250 km (original distance) to what is now the western foothills of the

  9. Progressive approach to eruption at Campi Flegrei caldera in southern Italy.

    Science.gov (United States)

    Kilburn, Christopher R J; De Natale, Giuseppe; Carlino, Stefano

    2017-05-15

    Unrest at large calderas rarely ends in eruption, encouraging vulnerable communities to perceive emergency warnings of volcanic activity as false alarms. A classic example is the Campi Flegrei caldera in southern Italy, where three episodes of major uplift since 1950 have raised its central district by about 3 m without an eruption. Individual episodes have conventionally been treated as independent events, so that only data from an ongoing episode are considered pertinent to evaluating eruptive potential. An implicit assumption is that the crust relaxes accumulated stress after each episode. Here we apply a new model of elastic-brittle failure to test the alternative view that successive episodes promote a long-term accumulation of stress in the crust. The results provide the first quantitative evidence that Campi Flegrei is evolving towards conditions more favourable to eruption and identify field tests for predictions on how the caldera will behave during future unrest.

  10. Structural and functional analysis of validoxylamine A 7'-phosphate synthase ValL involved in validamycin A biosynthesis.

    Directory of Open Access Journals (Sweden)

    Lina Zheng

    Full Text Available Validamycin A (Val-A is an effective antifungal agent widely used in Asian countries as crop protectant. Validoxylamine A, the core structure and intermediate of Val-A, consists of two C(7-cyclitol units connected by a rare C-N bond. In the Val-A biosynthetic gene cluster in Streptomyces hygroscopicus 5008, the ORF valL was initially annotated as a validoxylamine A 7'-phosphate(V7P synthase, whose encoded 497-aa protein shows high similarity with trehalose 6-phosphate(T6P synthase. Gene inactivation of valL abolished both validoxylamine A and validamycin A productivity, and complementation with a cloned valL recovered 10% production of the wild-type in the mutant, indicating the involvement of ValL in validoxylamine A biosynthesis. Also we determined the structures of ValL and ValL/trehalose complex. The structural data indicates that ValL adopts the typical fold of GT-B protein family, featuring two Rossmann-fold domains and an active site at domain junction. The residues in the active site are arranged in a manner homologous to that of Escherichia coli (E.coli T6P synthase OtsA. However, a significant discrepancy is found in the active-site loop region. Also noticeable structural variance is found around the active site entrance in the apo ValL structure while the region takes an ordered configuration upon binding of product analog trehalose. Furthermore, the modeling of V7P in the active site of ValL suggests that ValL might have a similar SNi-like mechanism as OtsA.

  11. Local magnitude scale for Valle Medio del Magdalena region, Colombia

    Science.gov (United States)

    Londoño, John Makario; Romero, Jaime A.

    2017-12-01

    A local Magnitude (ML) scale for Valle Medio del Magdalena (VMM) region was defined by using 514 high quality earthquakes located at VMM area and inversion of 2797 amplitude values of horizontal components of 17 stations seismic broad band stations, simulated in a Wood-Anderson seismograph. The derived local magnitude scale for VMM region was: ML =log(A) + 1.3744 ∗ log(r) + 0.0014776 ∗ r - 2.397 + S Where A is the zero-to-peak amplitude in nm in horizontal components, r is the hypocentral distance in km, and S is the station correction. Higher values of ML were obtained for VMM region compared with those obtained with the current formula used for ML determination, and with California formula. With this new scale ML values are adjusted to local conditions beneath VMM region leading to more realistic ML values. Moreover, with this new ML scale the seismicity caused by tectonic or fracking activity at VMM region can be monitored more accurately.

  12. A short review of our current understanding of the development of ring faults during collapse caldera formation

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    Adelina eGeyer

    2014-09-01

    Full Text Available The term collapse caldera refers to those volcanic depressions resulting from the sinking of the chamber roof due to the rapid withdrawal of magma during the course of an eruption. During the last three decades, collapse caldera dynamics has been the focus of attention of numerous, theoretical, numerical and experimental studies. Nonetheless, even if there is a tendency to go for a general and comprehensive caldera dynamics model, some key aspects remain unclear, controversial or completely unsolved. This is the case of ring fault nucleation points and propagation and dip direction. Since direct information on calderas’ deeper structure comes mainly from partially eroded calderas or few witnessed collapses, ring faults layout at depth remains still uncertain. This has generated a strong debate over the detailed internal fault and fracture configuration of a caldera collapse and, in more detail, how ring faults initiate and propagate. We offer here a very short description of the main results obtained by those analogue and theoretical/mathematical models applied to the study of collapse caldera formation. We place special attention on those observations related to the nucleation and propagation of the collapse-controlling ring faults. This summary is relevant to understand the current state-of-the-art of this topic and it should be taken under consideration in future works dealing with collapse caldera dynamics.

  13. Caracterización espectral y mineralógica de los suelos del valle del río Cauca por espectroscopía visible e infrarroja (400 - 2.500 nm

    Directory of Open Access Journals (Sweden)

    Bastidas Obando Ernesto

    2010-08-01

    Full Text Available Las librerías espectrales se utilizan para identificar diferentes
    tipos de suelo a partir de análisis espectrales que caracterizan su
    composición mineralógica y química. Los objetivos del presente
    trabajo consistieron en determinar si existen diferencias en el
    perfil espectral de los suelos del valle geográfico del río Cauca
    a nivel de subgrupo taxonómico; y cuantificar en sus perfiles
    espectrales la abundancia de minerales arcillosos. Por medio
    de un análisis de conglomerados se seleccionaron las muestras
    más homogéneas de cada subgrupo taxonómico para construir
    el perfil espectral de cada uno de ellos. El modelo linear spectral
    unmixing se utilizó para determinar las concentraciones de
    minerales arcillosos. A nivel de subgrupo taxonómico se observaron
    diferencias en la magnitud de los perfiles espectrales, así
    como en sus longitudes de onda a los 1.400, 1.900 y 2.200 nm.
    El modelo utilizado permite caracterizar de manera objetiva las
    concentraciones de minerales arcillosos de cada suelo a partir
    de su perfil espectral.

  14. Structural characteristics and collapse mechanism of the late Cretaceous Geumseongsan Caldera, SE Korea

    Science.gov (United States)

    Lee, S.; Cheon, Y.; Lee, Y.; Son, M.

    2017-12-01

    The Geumseongsan caldera provides an opportunity to understand the structural evolution of volcanic collapse and the role of paleostress. We focus on structural elements of the exhumed caldera floor to interpret the collapse mechanism. The caldera shows an NNW-trending elliptical shape (8×12 km). Basaltic and rhyolitic rocks are situated in the central high of the caldera, while pre-volcanic sedimentary rocks in the perimetric lowland of the volcanic rocks. Stratal attitudes change sharply from the outside to the inside of caldera bounded with a sub-vertical ring fault. The outside strata show a homocline toward SE about 15°, whereas the inside is divided into four structural domains (NE-, NW-, SE-, and SW-domains) based on the changing attitudes. The strata in NW- and SE-domains dip toward SE and NW, respectively, making an overall synclinal fold. While NE- and SW-domains comprise re-oriented, folded strata, which generally have NE- and SW-trending axes plunging toward the center. In addition, extensional and contractional structures occur distinctively in NW- and SE-domains and in NE- and SW-domains, respectively, indicating an axisymmetric deformation around NE-SW axis. The results indicate that higher horizontal mass movement toward the center occurred in NW- and SE-domains than in NE- and SW-domains while vertical mass movement was more active in the latter. This axisymmetric deformation could be produced by regional stress during the volcanic activity, which affected the collapse pattern of caldera floor. The regional stress field during the late Cretaceous is known as NW-SE horizontal maximum and NE-SW horizontal minimum stresses due to the oblique subduction of proto-Pacific Plate underneath Eurasian Plate. NNW-trending elliptical shape of the caldera is interpreted to have formed under the influence of this stresses, like a tension gash. The NW-SE maximum stress possibly acted to resist vertical displacement along the marginal fault of NW- and SE

  15. Ectopsocidae (Psocodea: 'Psocoptera') from Valle del Cauca and NNP Gorgona, Colombia.

    Science.gov (United States)

    Manchola, Oscar Fernando Saenz; Obando, Ranulfo González; Aldrete, Alfonso N García

    2014-04-14

    The results of a survey of the psocid family Ectopsocidae in Valle del Cauca and NNP Gorgona, are here presented. Fifteen species were identified, in the genera Ectopsocus (14 species), and Ectopsocopsis (one species); four of the Ectopsocus species are new to science and are here described and illustrated. The male of E. thorntoni García Aldrete is here described. Records of Ectopsocopsis cryptomeriae (Enderlein), Ectopsocus briggsi McLachlan, E. californicus Banks, E. columbianus Badonnel, E. maindroni Badonnel, E. meridionalis Ribaga, E. pilosus Badonnel, E. richardsi Pearman, E. titschacki Jentsch, and E. vilhenai Badonnel, are provided. Ten species were found only in Valle del Cauca, two species were found only in the NNP Gorgona, and three species were found at both sites. The specimens studied are deposited in the Entomological Museum, Universidad del Valle, Santiago de Cali, Colombia (MUSENUV).

  16. Diffusive Soil Degassing of Radon and Carbon Dioxide at Ilopango Caldera, El Salvador, Central America

    Science.gov (United States)

    Ransom, L.; Lopez, D. L.; Hernandez, P.

    2001-12-01

    Ilopango Caldera lies 10 Km east of San Salvador, El Salvador and holds Ilopango Lake, the largest body of fresh water in El Salvador. There is currently no observed fumarolic activity within the caldera system. However, the last eruption occurred in 1880. In November - December, 1999, radon gas concentrations (pCi/l) were measured using a Pylon AB5 radon monitor, and flux of CO2 (g/m2/day) was determined using the accumulation chamber method at 106 sampling stations around the lake, along and across the caldera walls. Gas samples were also collected to determine the isotopic composition of C in CO2. CO2 fluxes did not show high values characteristic of other volcanic systems, values ranged from 0.7 to 9.2 g/m2/day with an average value of 3.9. These values are similar to the low values of the background population observed in nearby San Salvador volcano. Highest values are observed to the east and west of the lake. Isotopic values for C in soil gases do not show an important magmatic component. Radon concentrations present three distinct populations with the highest values occurring to the southwest. Thoron concentrations are higher close to the caldera walls than inside the caldera due to the possible higher rock fracturing in that region. Measurements taken in March 2001, after the January 13 and February 13, 2001 earthquakes did not show significant variations in CO2 fluxes. However, radon concentrations varied due to the high seismicity that lasted several months after these earthquakes. These results suggest that the magmatic system of Ilopango Caldera is not emitting high fluxes of CO2 to the atmosphere throughout the caldera soils. Subaquatic emissions of CO2 have not been evaluated. However, subaquatic hydrothermal discharges have not been identified at this calderic lake.

  17. Amazonian volcanism inside Valles Marineris on Mars

    Czech Academy of Sciences Publication Activity Database

    Brož, Petr; Hauber, E.; Wray, J. J.; Michael, G.

    2017-01-01

    Roč. 473, September (2017), s. 122-130 ISSN 0012-821X Institutional support: RVO:67985530 Keywords : Mars * Valles Marineris * volcanism * scoria cone * hydrothermal activity Subject RIV: DC - Siesmology, Volcanology, Earth Structure OBOR OECD: Volcanology Impact factor: 4.409, year: 2016

  18. El valle de Mexicali: agricultura e inversión extranjera (1901-1986

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    Martha Stamatis Maldonado

    1987-01-01

    Full Text Available El interés de este trabajo es intentar explicar el desarrollo de la agricultura del valle de Mexicali a través de su relación con la inversión extranjera (norteamericana. Relación que está determinada por la función conformadora del sistema económico internacional representada por el capital norteamericano, la cual se va convirtiendo en un hecho, sobre todo a partir de 1940 en la integración nacional de las actividades económicas y sociales que se desarrollan en México. Este proceso de desarrollo ofrece manifestaciones particulares, la agricultura del valle no está ajena a las determinaciones ejercidas por el capital norteamericano sobre la agricultura nacional. De esta forma, este capital sigue manteniendo su presencia en el valle como parte de la función hegemónica para internacionalizar la agricultura mexicana. Las posibilidades que el valle tiene para un mayor crecimiento estriban en factores que permitirían un mayor desplazamiento de la producción de California, tomando en cuenta la corta distancia, entre otros, para que tuvieran un peso suficiente que las convirtiera en ventajas reales.

  19. Nuevos datos sobre Huaca China, Valle del Santa, Perú

    OpenAIRE

    Chapdelaine, Claude; Pimentel, Víctor; Gagné, Gérard; Gamboa, Jorge; Regalado, Delicia; Chicoine, David

    2015-01-01

    La presencia Moche en el valle del Santa se apoya en la existencia de numerosos sitios entre los cuales varios son considerados centros locales de importancia. Huaca China es uno de estos sitios estratégicos en la parte suroeste del valle. Las recolecciones de superficie y la limpieza de pozos de huaquero permiten la identificación de una presencia Moche y de una fuerte ocupación durante el Horizonte Medio. Además de presentar una sepultura de la cultura Tanguche, se describen los principales...

  20. Eruptive history, geochronology, and post-eruption structural evolution of the late Eocene Hall Creek Caldera, Toiyabe Range, Nevada

    Science.gov (United States)

    Colgan, Joseph P.; Henry, Christopher D.

    2017-02-24

    The magmatic, tectonic, and topographic evolution of what is now the northern Great Basin remains controversial, notably the temporal and spatial relation between magmatism and extensional faulting. This controversy is exemplified in the northern Toiyabe Range of central Nevada, where previous geologic mapping suggested the presence of a caldera that sourced the late Eocene (34.0 mega-annum [Ma]) tuff of Hall Creek. This region was also inferred to be the locus of large-magnitude middle Tertiary extension (more than 100 percent strain) localized along the Bernd Canyon detachment fault, and to be the approximate location of a middle Tertiary paleodivide that separated east and west-draining paleovalleys. Geologic mapping, 40Ar/39Ar dating, and geochemical analyses document the geologic history and extent of the Hall Creek caldera, define the regional paleotopography at the time it formed, and clarify the timing and kinematics of post-caldera extensional faulting. During and after late Eocene volcanism, the northern Toiyabe Range was characterized by an east-west trending ridge in the area of present-day Mount Callaghan, probably localized along a Mesozoic anticline. Andesite lava flows erupted around 35–34 Ma ponded hundreds of meters thick in the erosional low areas surrounding this structural high, particularly in the Simpson Park Mountains. The Hall Creek caldera formed ca. 34.0 Ma during eruption of the approximately 400 cubic kilometers (km3) tuff of Hall Creek, a moderately crystal-rich rhyolite (71–77 percent SiO2) ash-flow tuff. Caldera collapse was piston-like with an intact floor block, and the caldera filled with thick (approximately 2,600 meters) intracaldera tuff and interbedded breccia lenses shed from the caldera walls. The most extensive exposed megabreccia deposits are concentrated on or close to the caldera floor in the southwestern part of the caldera. Both silicic and intermediate post-caldera lavas were locally erupted within 400 thousand

  1. Lithium enrichment in intracontinental rhyolite magmas leads to Li deposits in caldera basins.

    Science.gov (United States)

    Benson, Thomas R; Coble, Matthew A; Rytuba, James J; Mahood, Gail A

    2017-08-16

    The omnipresence of lithium-ion batteries in mobile electronics, and hybrid and electric vehicles necessitates discovery of new lithium resources to meet rising demand and to diversify the global lithium supply chain. Here we demonstrate that lake sediments preserved within intracontinental rhyolitic calderas formed on eruption and weathering of lithium-enriched magmas have the potential to host large lithium clay deposits. We compare lithium concentrations of magmas formed in a variety of tectonic settings using in situ trace-element measurements of quartz-hosted melt inclusions to demonstrate that moderate to extreme lithium enrichment occurs in magmas that incorporate felsic continental crust. Cenozoic calderas in western North America and in other intracontinental settings that generated such magmas are promising new targets for lithium exploration because lithium leached from the eruptive products by meteoric and hydrothermal fluids becomes concentrated in clays within caldera lake sediments to potentially economically extractable levels.Lithium is increasingly being utilized for modern technology in the form of lithium-ion batteries. Here, using in situ measurements of quartz-hosted melt inclusions, the authors demonstrate that preserved lake sediments within rhyolitic calderas have the potential to host large lithium-rich clay deposits.

  2. Characterization of malaria mortality in Valle del Cauca, 2005-2006 Caracterización de la mortalidad por malaria en el Valle del Cauca, 2005-2006

    Directory of Open Access Journals (Sweden)

    Gloria Castro

    2009-12-01

    Full Text Available Introduction. Valle del Cauca is one of the states in Colombia that reports a high number of deaths due to malaria. Understanding the basis of malarial deaths is useful for assessing the efficacy of the health system and to identify areas where improvements are necessary to decrease malaria mortality.
    Objective. Potential determinants of mortality in malaria cases are characterized in a demographic study centered in Valle del Cauca.
    Materials and methods. A descriptive analysis was directed to 25 cases of malaria death occurring in Valle del Cauca during 2005 and 2006.
    Results. The mean age was 31.3 years (range, 2 to 71 yr, 11 were women (1 pregnant, 11 were from the malaria-endemic port of Buenaventura, and 5 from other Pacific coastal states. After entering the health system facility, the standard malaria diagnostic, the thick smear, was not ordered for 7 cases at any time during the treatment period. In cases where a thick smear was taken at first contact, 11 had a positive and 5 had a negative initial report. Cerebral malaria (7/18 cases and renal failure (6/18 cases were the most frequent complications. During hospitalization, 13/18 cases developed other complications, mainly acute lung edema (8/18 cases and shock (5/18 cases.
    Conclusions. Failures in primary health care of patients with malaria were recognized. This information has been used to implement actions aimed at improving initial care of malaria subjects in the health services of Valle del Cauca. The study recommends that other states in Colombia increase their efforts to decrease malaria mortality.Introducción. El Valle del Cauca es uno de los departamentos que mayor número de muertes por paludismo reporta en Colombia. El análisis de estas muertes permite una aproximación diagnóstica al funcionamiento del sistema de salud y contribuye a generar propuestas tendientes a disminuir la mortalidad por esta enfermedad.
    Objetivo. Caracterizar demogr

  3. Geochemical evolution of Ngorongoro Caldera, Northern Tanzania: Implications for crust magma interaction

    Science.gov (United States)

    Mollel, Godwin F.; Swisher, Carl C.; Feigenson, Mark D.; Carr, Michael J.

    2008-07-01

    Ngorongoro Caldera is the largest and best-preserved of nine Plio-Pleistocene volcanoes that make-up the Ngorongoro Volcanic Highlands (NVH) complex situated at the southern bifurcation of Gregory Rift, part of the East African Rift system of northern Tanzania. We report here, major and trace element abundances, Sr-Nd-Pb isotope analyses and 40Ar/ 39Ar laser incremental-heating and total fusion ages on lava and tephra sampled from stratigraphic sections exposed within the Ngorongoro Caldera. Major and trace elements measured on samples collected from the Ngorongoro Caldera wall indicate a stratified magma chamber whose silicic top and basaltic bottom was inverted by sequential eruptions. Samples from the lower part of the exposed Ngorongoro Caldera wall are high in silica, alkalis and HFSE (High Field Strength Elements). The Zr, Nb and Hf concentrations are highly correlated with each other and decrease up-section, indicative of the extent of magma evolution. Modeling of major, trace as well as Sr, Nd and Pb isotope data suggests that assimilation fractional crystallization processes were essential in producing the observed geochemical variations. The Sr and Nd isotope ratios from the Ngorongoro samples are widely dispersed ( 87Sr/ 86Sr = 0.70405 to 0.70801, 143Nd/ 144Nd = 0.512205 to 0.512623) and Pb isotope ratios are consistent with previous studies: 206Pb/ 204Pb = 18.73 to 19.37, 207Pb/ 204Pb = 15.64 to 15.69, 208Pb/ 204Pb = 39.52 to 39.55. Although Sr isotopic ratios are similar to Oceanic Island Basalt (OIB), the more radiogenic samples ( 87Sr/ 86Sr > 0.705) from the lower part of the section suggest crust-magma interaction; this is supported by Ce/Pb ratios (Ngorongoro Caldera wall section yield 40Ar/ 39Ar ages of 2.25 ± 0.02 Ma to 2.01 ± 0.02 Ma, constraining a duration of volcanism of the order of ~ 240 kyr. These ages suggest correlation of a normal to reverse geomagnetic polarity transition measured in the Ngorongoro Caldera wall section with the ~ 2

  4. Finite-element modeling of magma chamber-host rock interactions prior to caldera collapse

    Science.gov (United States)

    Kabele, Petr; Žák, Jiří; Somr, Michael

    2017-06-01

    Gravity-driven failure of shallow magma chamber roofs and formation of collapse calderas are commonly accompanied by ejection of large volumes of pyroclastic material to the Earth's atmosphere and thus represent severe volcanic hazards. In this respect, numerical analysis has proven as a key tool in understanding the mechanical conditions of caldera collapse. The main objective of this paper is to find a suitable approach to finite-element simulation of roof fracturing and caldera collapse during inflation and subsequent deflation of shallow magma chambers. Such a model should capture the dominant mechanical phenomena, for example, interaction of the host rock with magma and progressive deformation of the chamber roof. To this end, a comparative study, which involves various representations of magma (inviscid fluid, nearly incompressible elastic, or plastic solid) and constitutive models of the host rock (fracture and plasticity), was carried out. In particular, the quasi-brittle fracture model of host rock reproduced well the formation of tension-induced radial and circumferential fractures during magma injection into the chamber (inflation stage), especially at shallow crustal levels. Conversely, the Mohr-Coulomb shear criterion has shown to be more appropriate for greater depths. Subsequent magma withdrawal from the chamber (deflation stage) results in further damage or even collapse of the chamber roof. While most of the previous studies of caldera collapse rely on the elastic stress analysis, the proposed approach advances modeling of the process by incorporating non-linear failure phenomena and nearly incompressible behaviour of magma. This leads to a perhaps more realistic representation of the fracture processes preceding roof collapse and caldera formation.

  5. History of surface displacements at the Yellowstone Caldera, Wyoming, from leveling surveys and InSAR observations, 1923-2008

    Science.gov (United States)

    Dzurisin, Daniel; Wicks, Charles W.; Poland, Michael P.

    2012-01-01

    Modern geodetic studies of the Yellowstone caldera, Wyoming, and its extraordinary tectonic, magmatic, and hydrothermal systems date from an initial leveling survey done throughout Yellowstone National Park in 1923 by the U.S. Coast and Geodetic Survey. A repeat park-wide survey by the U.S. Geological Survey (USGS) and the University of Utah during 1975-77 revealed that the central part of the caldera floor had risen more than 700 mm since 1923, at an average rate of 14±1 mm/yr. From 1983 to 2007, the USGS conducted 15 smaller surveys of a single level line that crosses the northeast part of the caldera, including the area where the greatest uplift had occurred from 1923 to 1975-77. The 1983 and 1984 surveys showed that uplift had continued at an average rate of 22±1 mm/yr since 1975-77, but no additional uplift occurred during 1984-85 (-2±5 mm/yr), and during 1985-95 the area subsided at an average rate of 19±1 mm/yr. The change from uplift to subsidence was accompanied by an earthquake swarm, the largest ever recorded in the Yellowstone area (as of March 2012), starting in October 1985 and located near the northwest rim of the caldera. Interferometric synthetic aperture radar (InSAR) images showed that the area of greatest subsidence migrated from the northeast part of the caldera (including the Sour Creek resurgent dome) during 1992-93 to the southwest part (including the Mallard Lake resurgent dome) during 1993-95. Thereafter, uplift resumed in the northeast part of the caldera during 1995-96, while subsidence continued in the southwest part. The onset of uplift migrated southwestward, and by mid-1997, uplift was occurring throughout the entire caldera (essentially rim to rim, including both domes). Consistent with these InSAR observations, leveling surveys indicated 24±3 mm of uplift in the northeast part of the caldera during 1995-98. The beginning of uplift was coincident with or followed shortly after an earthquake swarm near the north caldera rim

  6. Ring-fault activity at subsiding calderas studied from analogue experiments and numerical modeling

    Science.gov (United States)

    Liu, Y. K.; Ruch, J.; Vasyura-Bathke, H.; Jonsson, S.

    2017-12-01

    Several subsiding calderas, such as the ones in the Galápagos archipelago and the Axial seamount in the Pacific Ocean have shown a complex but similar ground deformation pattern, composed of a broad deflation signal affecting the entire volcanic edifice and of a localized subsidence signal focused within the caldera. However, it is still debated how deep processes at subsiding calderas, including magmatic pressure changes, source locations and ring-faulting, relate to this observed surface deformation pattern. We combine analogue sandbox experiments with numerical modeling to study processes involved from initial subsidence to later collapse of calderas. The sandbox apparatus is composed of a motor driven subsiding half-piston connected to the bottom of a glass box. During the experiments the observation is done by five digital cameras photographing from various perspectives. We use Photoscan, a photogrammetry software and PIVLab, a time-resolved digital image correlation tool, to retrieve time-series of digital elevation models and velocity fields from acquired photographs. This setup allows tracking the processes acting both at depth and at the surface, and to assess their relative importance as the subsidence evolves to a collapse. We also use the Boundary Element Method to build a numerical model of the experiment setup, which comprises contracting sill-like source in interaction with a ring-fault in elastic half-space. We then compare our results from these two approaches with the examples observed in nature. Our preliminary experimental and numerical results show that at the initial stage of magmatic withdrawal, when the ring-fault is not yet well formed, broad and smooth deflation dominates at the surface. As the withdrawal increases, narrower subsidence bowl develops accompanied by the upward propagation of the ring-faulting. This indicates that the broad deflation, affecting the entire volcano edifice, is primarily driven by the contraction of the

  7. Shed Some Light on the Subject: Teaching Ramon del Valle-Inclan's "Luces de bohemia"

    Science.gov (United States)

    Parker, Jason Thomas

    2011-01-01

    This essay seeks to provide parallel and interchangeable approaches to teaching Ramon del Valle-Inclan's challenging play "Luces de bohemia". A greater understanding of the cultural and mental frameworks of the early twentieth-century Spanish spectator will permit students to penetrate the dense intertextuality that characterizes Valle's…

  8. Tianmujian caldera. A potential area for locating rich and large uranium deposit

    International Nuclear Information System (INIS)

    Lin Ziyu; Xu Jinshan; Chen Mingzhuo; Jiang Jinyuan; Fan Honghai; Cheng Qi

    2001-01-01

    Based on the comprehensive analysis on geologic, remote sensing, gravimetric, magnetic and geochemical data, and the field geologic investigation, the author has preliminarily ascertained the formation and the distribution characteristics of the Tianmujian caldera, and recognized the porphyroclastic lava system which is extensively distributed in the area. The authors suggest that the Tianmujian volcanic basin experienced two evolution stages--the thermal uplifting and the formation of caldera, that large concealed uranium-rich granitic massif occurs in the area, and during the vertical evolution process the uranium showed its concentration in the lower part and depletion in the upper part, and large amount of ore-forming material moved upward along with the magmatic hydrothermals entering the caldera to form uranium deposit. In addition, it is clarified that the NE-NW rhombic-formed basement structural pattern is predominated by the NE-trending fault. At the same time, the important role of the basement faults in controlling the magmatic activities, in the formation of volcanic basins, as well as the formation of uranium mineralization is emphasized. On the basis of the above comprehensive analysis the authors suggest that the Tianmujian caldera is a quite favourable potential area for possessing the basic conditions necessary for the formation of rich and large uranium deposit including uranium 'source, migration, concentration, preservation' and favourable multiple metallogenic information is displayed in the Tianmujian area

  9. The Tala Tuff, La Primavera caldera Mexico. Pre-eruptive conditions and magma processes before eruption

    Science.gov (United States)

    Sosa-Ceballos, G.

    2015-12-01

    La Primavera caldera, Jalisco Mexico, is a Pleistocenic volcanic structure formed by dome complexes and multiple pyroclastic flows and fall deposits. It is located at the intersection of the Chapala, Colima, and Tepic grabens in western Mexico. The first volcanic activity associated to La Primavera started ~0.1 Ma with the emission of pre-caldera lavas. The caldera collapse occurred 95 ka and is associated to the eruption of ~20 km3of pumice flows known as the Tala tuff (Mahood 1980). The border of the caldera was replaced by a series of domes dated in 75-30 ky, which partially filled the inner depression of the caldera with pyroclastic flows and falls. For more than a decade the Federal Commission of Electricity in Mexico (CFE) has prospected and evaluated the geothermal potential of the Cerritos Colorados project at La Primavera caldera. In order to better understand the plumbing system that tapped the Tala tuff and to investigate its relation with the potential geothermal field at La Primavera we performed a series of hydrothermal experiments and studied melt inclusions hosted in quartz phenocrysts by Fourier Infra red stectroscopy (FTIR). Although some post caldera products at La Primavera contain fayalite and quartz (suggesting QFM conditions) the Tala tuff does not contain fayalite and we ran experiments under NNO conditions. The absence of titanomagnetite does not allowed us to calculate pre-eruptive temperature. However, the stability of quartz and plagioclase, which are natural phases, suggest that temperature should be less than 750 °C at a pressure of 200 MPa. The analyses of H2O and CO2 dissolved in melt inclusions yielded concentrations of 2-5 wt.% and 50-100 ppm respectively. This data confirm that the pre-eruptive pressure of the Tala tuff is ~200 MPa and in addition to major elements compositions suggest that the Tala tuff is either, compositionally zoned or mixed with other magma just prior to eruption.

  10. Qualitative and Quantitative Assessment of Naturals Hazards in the Caldera of Mount Bambouto (West Cameroon)

    Science.gov (United States)

    Zangmo Tefogoum, G.; Kagou Dongmo, A.; Nkouathio, D. G.; Wandji, P.

    2009-04-01

    Mount Bambouto is polygenic stratovolcano of the Cameroon Volcanic Line, build between 21 Ma and 4,5Ma (Nkouathio et al., 2008). It is situated at about 200 km NE of mount Cameroon, at 09°55' and 10°15' East and, 05°25' and 05°50' Nord. This volcano covers an area of 500 Km2 and culminates at 2740 m at Meletan hill and bears a collapse caldera (13 x 8 km). Fissural, extrusive and explosive dynamism are responsible of the construction in three main stages this volcano including the edification of a sommital large rim caldera. Mount Bambouto structure gives rise to different natural hazards, of volcanological origin and meteorological origin. In the past time, landslides, floodings, firebush, blocks collapse took place in this area with catastrophic impact on the population. New research program had been carried out in the caldera concerning qualitative and quantitative evaluation of natural risks and catastrophes. The main factors of instability are rain, structure of the basement, slopes, lithology and anthropic activities; particularly, the occurrence of exceptional rainfall due to global change are relevant; this gives opportunity to draw landslides hazards zonation map of the Bambouto caldera which is the main risk in this area. We evaluate the financial potential of the caldera base on the average income of breeding, farming, school fees and the cost of houses and equipments for each family. The method of calculation revealed that, the yearly economy of the mounts Bambouto caldera represents about 2 billions FCFA. Some recommendations have been made in order to prevent and reduced the potential losses and the number of victims in particular by better land use planning. These help us to estimate the importance of destruction of the environment and biodiversity in case of catastrophes. We conclude that in the Bambouto caldera there is moderate to high probability that destructive phenomena due to landslides occurs within the upcoming years with enormous

  11. Growth of intra-caldera lava domes controlled by various modes of caldera collapse, the Štiavnica volcano-plutonic complex, Western Carpathians

    Czech Academy of Sciences Publication Activity Database

    Tomek, Filip; Žák, J.; Holub, F. V.; Chlupáčová, M.; Verner, K.

    2016-01-01

    Roč. 311, February 1 (2016), s. 183-197 ISSN 0377-0273 Institutional support: RVO:67985831 Keywords : andesite * anisotropy of magnetic susceptibility (AMS) * collapse caldera * lava dome * magma flow * stratovolcano Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.492, year: 2016

  12. Long Valley Caldera Lake and reincision of Owens River Gorge

    Science.gov (United States)

    Hildreth, Wes; Fierstein, Judy

    2016-12-16

    Owens River Gorge, today rimmed exclusively in 767-ka Bishop Tuff, was first cut during the Neogene through a ridge of Triassic granodiorite to a depth as great as its present-day floor and was then filled to its rim by a small basaltic shield at 3.3 Ma. The gorge-filling basalt, 200 m thick, blocked a 5-km-long reach of the upper gorge, diverting the Owens River southward around the shield into Rock Creek where another 200-m-deep gorge was cut through the same basement ridge. Much later, during Marine Isotope Stage (MIS) 22 (~900–866 ka), a piedmont glacier buried the diversion and deposited a thick sheet of Sherwin Till atop the basalt on both sides of the original gorge, showing that the basalt-filled reach had not, by then, been reexcavated. At 767 ka, eruption of the Bishop Tuff blanketed the landscape with welded ignimbrite, deeply covering the till, basalt, and granodiorite and completely filling all additional reaches of both Rock Creek canyon and Owens River Gorge. The ignimbrite rests directly on the basalt and till along the walls of Owens Gorge, but nowhere was it inset against either, showing that the basalt-blocked reach had still not been reexcavated. Subsidence of Long Valley Caldera at 767 ka produced a steep-walled depression at least 700 m deeper than the precaldera floor of Owens Gorge, which was beheaded at the caldera’s southeast rim. Caldera collapse reoriented proximal drainages that had formerly joined east-flowing Owens River, abruptly reversing flow westward into the caldera. It took 600,000 years of sedimentation in the 26-km-long, usually shallow, caldera lake to fill the deep basin and raise lake level to its threshold for overflow. Not until then did reestablishment of Owens River Gorge begin, by incision of the gorge-filling ignimbrite.

  13. Evolution and relationships between volcanism and tectonics in the central-eastern part of the Oligocene Borovitsa caldera (Eastern Rhodopes, Bulgaria)

    Science.gov (United States)

    Dhont, Damien; Yanev, Yotzo; Bardintzeff, Jacques-Marie; Chorowicz, Jean

    2008-04-01

    The nested Borovitsa caldera emplaced during the collision-related Paleogene volcanism in the Eastern Rhodopes. The pre-caldera succession consists in Priabonian to Early Oligocene sediments and lavas (absarokites, shoshonites, latites). The caldera filling corresponds to an acid volcanism Early Oligocene in age. The tectono-magmatic evolution of the caldera can be divided into six main stages. (1) Ignimbritic units (more than 1.5 km thick) with a trachydacitic to trachytic composition deposited. The K-Ar method yields an age of 34-33.5 Ma. The volcanic products are either strongly or not welded in the western and eastern parts of the caldera, respectively. (2) An initial Murga caldera, 7-10 km in diameter, collapsed. This event was accompanied by the intrusion of a circular body consisting of lenses-bearing rocks of trachyrhyodacitic to rhyolitic composition within the border faults. (3) The emission of pyroclastic rocks continued and a large sub-volcanic body (33 Ma) of trachydacitic to trachyrhyolitic composition intruded in the western part of the circular body. (4) The Borovitsa caldera (15 km × 34 km) collapsed. Rhyolitic and trachydacitic dykes dated at 32.5 Ma intruded along its border faults. (5) High-Si trachyrhyolitic-perlitic domes intruded in the eastern part of the Borovitsa caldera at 30-32 Ma and the Dushka caldera collapsed within the Borovitsa structure. (6) Dykes of various compositions (from shoshonite to rhyolite) and trachydacitic to rhyolitic sub-volcanic stocks finally intruded within the caldera and along its rims at 27.5-29.5 Ma. Observations on radar and optical satellite imagery allowed both a new mapping of the structural pattern in the Borovitsa caldera and the understanding of the relationships between faulting and volcanism in this area. Horse-tail features accommodating the right-lateral throw component at the termination of NW-SE and N-S right-lateral strike-slip faults are superimposed upon the Murga caldera and the eastern part

  14. Kadunud üheksakümnendad / Valle-Sten Maiste

    Index Scriptorium Estoniae

    Maiste, Valle-Sten, 1972-

    1999-01-01

    Sisaldab 2 proosaraamatute loetelu: 1998 a. ilmunud proosaraamatuid ; Eesti iseseisvusaastate proosa tipud ja täpid : [1992-1997]. Eesti kirjandusest 1990-ndatel. Vastukaja : Raudam, Toomas. Valle-Sten Maiste surm ja igavene elu // Sirp (1999) 16. apr., lk. 7

  15. Monitoring super-volcanoes: geophysical and geochemical signals at Yellowstone and other large caldera systems.

    Science.gov (United States)

    Lowenstern, Jacob B; Smith, Robert B; Hill, David P

    2006-08-15

    Earth's largest calderas form as the ground collapses during immense volcanic eruptions, when hundreds to thousands of cubic kilometres of magma are explosively withdrawn from the Earth's crust over a period of days to weeks. Continuing long after such great eruptions, the resulting calderas often exhibit pronounced unrest, with frequent earthquakes, alternating uplift and subsidence of the ground, and considerable heat and mass flux. Because many active and extinct calderas show evidence for repetition of large eruptions, such systems demand detailed scientific study and monitoring. Two calderas in North America, Yellowstone (Wyoming) and Long Valley (California), are in areas of youthful tectonic complexity. Scientists strive to understand the signals generated when tectonic, volcanic and hydrothermal (hot ground water) processes intersect. One obstacle to accurate forecasting of large volcanic events is humanity's lack of familiarity with the signals leading up to the largest class of volcanic eruptions. Accordingly, it may be difficult to recognize the difference between smaller and larger eruptions. To prepare ourselves and society, scientists must scrutinize a spectrum of volcanic signals and assess the many factors contributing to unrest and toward diverse modes of eruption.

  16. History of the Magmatic Feeding System of the Campi Flegrei Caldera

    Science.gov (United States)

    Orsi, G.; Civetta, L.; Arienzo, I.; D'Antonio, M.; di Renzo, V.; di Vito, M. A.

    2007-12-01

    The definition of the magmatic feeding system of active volcanoes, in terms of composition, time-scale of crystallization, relation between composition of the erupted magma and structural position of vents, magma chamber processes and architecture, is of extreme importance for the hazard evaluation. The studies that are carried out for the definition of the magmatic systems include detailed mineralogical, geochemical and isotopic analyses (Sr, Nd, Pb). The Campi Flegrei caldera magmatic structure is characterized by deep and shallow magma chambers. In the deep reservoir (20-10 km depth) mantle derived magmas differentiate and are contaminated with continental crust. In the shallow reservoirs isotopically distinct magmas further differentiate, mix and mingle before the eruptions. These processes generated isotopically distinct components that were variably involved along different structures of the Campi Flegrei caldera during time. At Campi Flegrei caldera the relation between the structural position of the eruptive vent, for the last 14 ka of activity, and the isotopic composition of the emitted magma allow us to reconstruct the architecture of the magmatic feeding system and to infer the chemical and isotopic composition, and the magma chamber location and processes, of the future eruption, according to the position of the vent

  17. El Camino de los Llanos - entre los valles de Chicama y Moche

    OpenAIRE

    Bernabé Romero, Joseph A.; Ministerio de Cultura

    2014-01-01

    Un indicador importante para la identificación del camino de la costa es su infraestructura lineal o la rectitud de su trazo, sobre todo al ingreso de los valles irrigados, siempre orientado de Norte – Sur, cruza la franja costera de forma longitudinal asociado a caminos trasversales que continúan por los principales valles. Otro aspecto a destacar del camino costero es su asociación a sitios locales que pueden o no tener componentes incas en su conformación.

  18. Intra-caldera active fault: An example from the Mw 7.0 2016 Kumamoto, Japan, earthquake

    Science.gov (United States)

    Toda, S.; Murakami, T.; Takahashi, N.

    2017-12-01

    A NE-trending 30-km-long surface rupture with up to 2.4 m dextral slip emerged during the Mw=7.0 16 April 2016 Kumamoto earthquake along the previously mapped Futagawa and northern Hinagu fault systems. The 5-km-long portion of the northeast rupture end, which was previously unidentified, crossed somma and extended to the 20-km-diameter Aso Caldera, one of the major active volcanoes, central Kyushu. We here explore geologic exposures of interplays of active faulting and active volcanism, and then argue the Futagawa fault system has been influenced by the ring fault system associated with the caldera forming gigantic eruptions since 270 ka, last of which occurred 90 ka ejecting a huge amount of ignimbrite. To understand the interplays, together with the mapping of the 2016 rupture, we employed an UAV to capture numerous photos of the exposures along the canyon and developed 3D orthochromatic topographic model using PhotoScan. One-hundred-meter-deep Kurokawa River canyon by the Aso Caldera rim exposes two lava flow units of 50 ka vertically offset by 10 m by the Futatawa fault system. Reconstructions of the collapsed bridges across the Kurokawa River also reveal cross sections of a 30-meter-high tectonic bulge and 10-m-scale negative flower structure deformed by the frequent fault movements. We speculate two fault developing models across the Aso Caldera. One is that the NE edge of the Futagawa fault system was cut and reset by the caldera forming ring fault, which indicates the 3-km-long rupture extent within the Aso Caldera would be a product of the fault growth since the last Aso-4 eruption of 90 ka. It enables us to estimate the 33 mm/yr of the fault propagation speed. An alternative model is that subsurface rupture of the Kumamoto earthquake extended further to the NE rim, the other side of the caldera edge, which is partially supported by the geodetic and seismic inversions. With respect to the model, the clear surface rupture of the 2016 Kumamoto earthquake

  19. Resurgent Toba – field, chronologic, and model constraints on time scales and mechanisms of resurgence at large calderas

    Directory of Open Access Journals (Sweden)

    Shanaka L De Silva

    2015-06-01

    Full Text Available New data reveal details of the post-caldera history at the Earth’s youngest resurgent supervolcano, Toba caldera in Sumatra. Resurgence after the caldera-forming ~74 ka Youngest Toba Tuff eruption uplifted the caldera floor as a resurgent dome, Samosir Island, capped with 100m of lake sediments. 14C age data from the uppermost datable sediments reveal that Samosir Island was submerged beneath lake level (~900m a.s.l ~33.7 ky. Since then, Samosir experienced 700m of uplift as a tilted block dipping to the west. Using 14C ages and elevations of sediment along a transect of Samosir reveal that minimum uplift rates were ~4.9 cm/yr from ~33.7 to 22.5 ka, but diminished to ~0.7 cm/yr after 22.5ka. Thermo-mechanical models informed by these rates reveal that detumescence does not produce the uplift nor the uplift rates estimated for Samosir. However, models calculating the effect of volume change of the magma reservoir within a temperature-dependent viscoelastic host rock reveal that a single pulse of ~475 km3 of magma produces a better fit to the uplift data than a constant flux. Reproducing the uplift rates require more sophisticated models. Motivation for resurgent uplift of the caldera floor is rebound of remnant magma as the system re-established magmastatic and isostatic equilibrium after the caldera collapse. Previous assertions that the caldera floor was apparently at 400m a.s.l or lower requires that uplift must have initiated between sometime between 33.7 ka and 74 ka at a minimum average uplift rate of ~1.1 cm/ year. The change in uplift rate from pre-33.7 ka to immediately post-33.7 ka suggests a role for deep recharge augmenting rebound. Average minimum rates of resurgent uplift at Toba are at least an order of magnitude slower than net rates of restlessness at currently active calderas. This connotes a distinction between resurgence and restlessness controlled by different processes, scales of process, and controlling variables.

  20. Geology of the Mid-Miocene Rooster Comb Caldera and Lake Owyhee Volcanic Field, eastern Oregon: Silicic volcanism associated with Grande Ronde flood basalt

    Science.gov (United States)

    Benson, Thomas R.; Mahood, Gail A.

    2016-01-01

    The Lake Owyhee Volcanic Field (LOVF) of eastern Oregon consists of rhyolitic caldera centers and lava fields contemporaneous with and spatially related to Mid-Miocene Columbia River flood basalt volcanism. Previous studies delineated two calderas in the southeastern part of LOVF near Owyhee Reservoir, the result of eruptions of two ignimbrites, the Tuff of Leslie Gulch and the Tuff of Spring Creek. Our new interpretation is that these two map units are differentially altered parts of a single ignimbrite produced in a major phreatomagmatic eruption at 15.8 Ma. Areas previously mapped as Tuff of Spring Creek are locations where the ignimbrite contains abundant clinoptilolite ± mordenite, which made it susceptible to erosion. The resistant intracaldera Tuff of Leslie Gulch has an alteration assemblage of albite ± quartz, indicative of low-temperature hydrothermal alteration. Our new mapping of caldera lake sediments and pre- and post-caldera rhyolitic lavas and intrusions that are chemically similar to intracaldera Tuff of Leslie Gulch point to a single 20 × 25 km caldera, which we name the Rooster Comb Caldera. Erosion of the resurgently uplifted southern half of the caldera created dramatic exposures of intracaldera Tuff of Leslie Gulch cut by post-caldera rhyolite dikes and intrusions that are the deeper-level equivalents of lava domes and flows that erupted into the caldera lake preserved in exposures to the northeast. The Rooster Comb Caldera has features in common with more southerly Mid-Miocene calderas of the McDermitt Volcanic Field and High Rock Caldera Complex, including formation in a basinal setting shortly after flood basalt eruptions ceased in the region, and forming on eruption of peralkaline ignimbrite. The volcanism at Rooster Comb Caldera postdates the main activity at McDermitt and High Rock, but, like it, begins 300 ky after flood basalt volcanism begins in the area, and while flood basalts don't erupt through the silicic focus, are

  1. Geologic field trip guide to Mount Mazama and Crater Lake Caldera, Oregon

    Science.gov (United States)

    Bacon, Charles R.; Wright, Heather M.

    2017-08-08

    Crater Lake partly fills one of the most spectacular calderas of the world—an 8 by 10 kilometer (km) basin more than 1 km deep formed by collapse of the Mount Mazama volcano during a rapid series of explosive eruptions ~7,700 years ago. Having a maximum depth of 594 meters (m), Crater Lake is the deepest lake in the United States. Crater Lake National Park, dedicated in 1902, encompasses 645 square kilometers (km2) of pristine forested and alpine terrain, including the lake itself, and virtually all of Mount Mazama. The geology of the area was first described in detail by Diller and Patton (1902) and later by Williams (1942), whose vivid account led to international recognition of Crater Lake as the classic collapse caldera. Because of excellent preservation and access, Mount Mazama, Crater Lake caldera, and the deposits formed by the climactic eruption constitute a natural laboratory for study of volcanic and magmatic processes. For example, the climactic ejecta are renowned among volcanologists as evidence for systematic compositional zonation within a subterranean magma chamber. Mount Mazama’s climactic eruption also is important as the source of the widespread Mazama ash, a useful Holocene stratigraphic marker throughout the Pacific Northwest United States, adjacent Canada, and offshore. A detailed bathymetric survey of the floor of Crater Lake in 2000 (Bacon and others, 2002) provides a unique record of postcaldera eruptions, the interplay between volcanism and filling of the lake, and sediment transport within this closed basin. Knowledge of the geology and eruptive history of the Mount Mazama edifice, enhanced by the caldera wall exposures, gives exceptional insight into how large volcanoes of magmatic arcs grow and evolve. In addition, many smaller volcanoes of the High Cascades beyond the limits of Mount Mazama provide information on the flux of mantle-derived magma through the region. General principles of magmatic and eruptive processes revealed by

  2. Application of electric and electromagnetic methods to the definition of the Campi Flegrei caldera (Italy

    Directory of Open Access Journals (Sweden)

    G. Cecere

    2000-06-01

    Full Text Available The results of an analysis of Dipolar Geoelectrical (DG, Magnetotelluric (MT and Self-Potential (SP data collected over the emerged portion of the Campi Flegrei (CF caldera (South Italy are presented. The DG and MT data are from previous surveys, while the SP data have been recently collected during a survey consisting of 265 pickup land sites. Although the emerged part of the CF caldera appears as a highly inhomogeneous structure, a few simple features have been highlighted through an integrated analysis of subsets of consistent data. A well resolved feature is the structural pattern of the caldera depression along a roughly E-W profile, deduced from a 2D combined interpretation of the MT and DG soundings. Resistivity dispersion effects have also been observed at both ends of this profile. They have been ascribed to the presence of hydrothermally altered zones related to the main fracture systems bordering the caldera. A pressure/temperature source body at a mean depth of about 5 km bsl under the Bay of Pozzuoli has been inferred from the analysis of the 3D SP tomography imaging.

  3. Geologic Map of Mount Mazama and Crater Lake Caldera, Oregon

    Science.gov (United States)

    Bacon, Charles R.

    2008-01-01

    Crater Lake partly fills one of the most spectacular calderas of the world, an 8-by-10-km basin more than 1 km deep formed by collapse of the volcano known as Mount Mazama (fig. 1) during a rapid series of explosive eruptions about 7,700 years ago. Having a maximum depth of 594 m, Crater Lake is the deepest lake in the United States. Crater Lake National Park, dedicated in 1902, encompasses 645 km2 of pristine forested and alpine terrain, including the lake itself, virtually all of Mount Mazama, and most of the area of the geologic map. The geology of the area was first described in detail by Diller and Patton (1902) and later by Williams (1942), whose vivid account led to international recognition of Crater Lake as the classic collapse caldera. Because of excellent preservation and access, Mount Mazama, Crater Lake caldera, and the deposits formed by the climactic eruption constitute a natural laboratory for study of volcanic and magmatic processes. For example, the climactic ejecta are renowned among volcanologists as evidence for systematic compositional zonation within a subterranean magma chamber. Mount Mazama's climactic eruption also is important as the source of the widespread Mazama ash, a useful Holocene stratigraphic marker throughout the Pacific Northwest, adjacent Canada, and offshore. A detailed bathymetric survey of the floor of Crater Lake in 2000 (Bacon and others, 2002) provides a unique record of postcaldera eruptions, the interplay between volcanism and filling of the lake, and sediment transport within this closed basin. Knowledge of the geology and eruptive history of the Mount Mazama edifice, greatly enhanced by the caldera wall exposures, gives exceptional insight into how large volcanoes of magmatic arcs grow and evolve. Lastly, the many smaller volcanoes of the High Cascades beyond the limits of Mount Mazama are a source of information on the flux of mantle-derived magma through the region. General principles of magmatic and eruptive

  4. Peligros hidrometeorológicos en un valle árido: abordaje geopedológico

    Directory of Open Access Journals (Sweden)

    Raúl Emmanuel Ocaña

    2018-01-01

    Full Text Available Se expone el análisis geopedológico del valle intermontano de Zonda, Argentina, con el objetivo de que este sea aplicado en estudios de ordenamiento territorial. Los resultados indican que los riesgos provienen de tres cuencas principales: dos locales (bajadas pedemontanas, río Seco de la Ciénaga y una regional (río San Juan, cada una con sus propias características. Los peligros más importantes corresponden a procesos de aluviones e inundaciones provenientes de los límites del valle y desbordes de los máximos caudales estivales del río San Juan. Los resultados fueron presentados en mapas que contienen unidades de relieve y riesgos hidrometeorológicos asociados. Los asentamientos humanos crecen en el valle en contacto con el piedemonte y están amenazados principalmente por aluviones de recurrencia anual y estival.

  5. Peligros hidrometeorológicos en un valle árido: abordaje geopedológico

    Directory of Open Access Journals (Sweden)

    Raúl Emmanuel Ocaña

    2018-01-01

    Full Text Available Se expone el análisis geopedológico del valle intermontano de Zonda, Argentina, con el objetivo de que este sea aplicado en estudios de ordenamiento territorial. Los resultados indican que los riesgos provienen de tres cuencas principales: dos locales (río San Juan, río Seco de la Ciénaga y una regional (bajadas pedemontanas, cada una con sus propias características. Los peligros más importantes corresponden a procesos de aluviones e inundaciones provenientes de los límites del valle y desbordes de los máximos caudales estivales del río San Juan. Los resultados fueron presentados en mapas que contienen unidades de relieve y riesgos hidrometeorológicos asociados. Los asentamientos humanos crecen en el valle en contacto con el piedemonte y están amenazados principalmente por aluviones de recurrencia anual y estival.

  6. Caldera de recuperación de gases perdidos

    OpenAIRE

    Camacho Thielepape, Daniel José

    2011-01-01

    El objeto de este proyecto es describir las instalaciones de la caldera de recuperación de gases perdidos. Más concretamente, las instalaciones de una nueva Planta de Reciclado de Aceite Lubricante en el Campo de Gibraltar, ubicada en el Polígono Industrial del término municipal de San Roque (Cádiz).

  7. Assessing volcanic hazard at the most populated caldera in the world: Campi Flegrei, Southern Italy

    Science.gov (United States)

    Somma, R.; de Natale, G.; Troise, C.; Kilburn, C.; Moretti, R.

    2017-12-01

    Naples and its hinterland in Southern Italy are one of the most urbanized areas in the world under threat from volcanic activity. The region lies within range of three active volcanic centers: Vesuvius, Campi Flegrei, and Ischia. The Campi Flegrei caldera, in particular, has been in unrest for six decades. The unrest followed four centuries of quiescence and has heightened concern about an increased potential for eruption. Innovative geochemical and geophysical analysis, combined with scientific drilling, are being used to investigate Campi Flegrei. Results highlight key directions for better understanding the mechanisms of caldera formation and the respective roles of magma intrusion and hydrothermal activity in determining the volcano's behavior. They also provide a framework for evaluating and mitigating the risk from this caldera and other large ones worldwide.

  8. Polimorfismos de grupos sanguíneos en Cachi, Valle Calchaqui, Salta

    OpenAIRE

    Acreche, Noemí; Albeza, María V.; Caruso, Graciela; Acosta, Rebeca; Felix, Sebastián

    2001-01-01

    El Departamento de Cachi, en la Provincia de Salta pertenece a los Valles Calchaquíes, los que se extienden además por Catamarca y Tucumán, constituyéndose en una región importante en la comunicación entre el Valle de Lerma y la Puna. Hasta el momento no se conocen datos de la genética de estas poblaciones, salvo los publicados por Matson en 1968 registrados en otra región de la provincia. A partir de la determinación de los grupos: ABO, MN, Ss, Cc, Dd, Ee, P, Diego y Kell-Cellano, Duffy y...

  9. History of the magmatic feeding system of the Campi Flegrei caldera (Italy)

    Science.gov (United States)

    Civetta, L.; Arienzo, I.; D'Antonio, M.; di Renzo, V.; di Vito, M. A.; Orsi, G.

    2007-05-01

    The definition of the magmatic feeding system of active volcanoes in terms of architecture, composition, crystallization time-scale, relationships between composition of the erupted magmas and structural position of the vents, and magma processes, is of paramount importance for volcanic hazards evaluation. Investigations aimed at defining the Campi Flegeri magmatic system, include detailed mineralogical, geochemical and isotopic analyses (Sr, Nd, Pb, Th,U). The magmatic feeding system of the Campi Flegrei caldera is characterized by deep and shallow magma reservoirs. In the deep reservoirs (20-10 km depth) mantle- derived magmas differentiated and were contaminated by continental crust. In the shallow reservoirs isotopically distinct magmas, further differentiated, contaminated, and mixed and mingled before eruptions. These processes generated isotopically distinct components, variably interacting with the different structural elements of the Campi Flegrei caldera through time. The relationships between the structural position of the eruption vents, during the last 15 ka of activity, and the isotopic composition of the magmas erupted at the Campi Flegrei caldera allow us to reconstruct the architecture of the magmatic feeding system and to infer the chemical and isotopic composition of the magma feeding a future eruption, according to vent position.

  10. Chapter 5. Plant gathering, game hunting, fishing, mineral collecting, and agriculture

    Science.gov (United States)

    Kurt F. Anschuetz

    2007-01-01

    Native American populations have cut wood for shelters and fuel, gathered native plants, hunted game animals, and collected various other resources, such as obsidian for making chipped-stone tools, clay for crafting pottery vessels, and stone slabs for producing piki (corn meal paper bread) griddles, in the Valles Caldera National Preserve (VCNP) for countless...

  11. Hollow volcanic tumulus caves of Kilauea Caldera, Hawaii County, Hawaii

    Directory of Open Access Journals (Sweden)

    William R. Halliday

    1998-01-01

    Full Text Available In addition to lava tube caves with commonly noted features, sizable subcrustal spaces of several types exist on the floor of Kilauea Caldera. Most of these are formed by drainage of partially stabilized volcanic structures enlarged or formed by injection of very fluid lava beneath a plastic crust. Most conspicuous are hollow tumuli, possibly first described by Walker in 1991. Walker mapped and described the outer chamber of Tumulus E-I Cave. Further exploration has revealed that it has a hyperthermic inner room beneath an adjoining tumulus with no connection evident on the surface. Two lengthy, sinuous hollow tumuli also are present in this part of the caldera. These findings support Walkers conclusions that hollow tumuli provide valuable insights into tumulus-forming mechanisms, and provide information about the processes of emplacement of pahoehoe sheet flows.

  12. Lembah Elqui / Valle de Elqui / Elqui Valley

    Directory of Open Access Journals (Sweden)

    Ian Campbell

    2017-05-01

    Full Text Available The three versions of Ian Campbell’s poem about Valle de Elqui (in Chile presented here comprise a poem he first wrote in Spanish, then in English and finally in a more powerful version in Indonesian, which was published in 2012 in the literary pages of the Jakarta mass media daily Kompas. Campbell regards this whole process as emblematic of his explorations in trilingual poetics, namely what does a ‘concept’/poem idea look like if done in the three languages with which he has some degree of written knowledge or fluency: English, Spanish, Indonesian. This mirrors the ‘three-pronged’ title ‘Selatan-Sur-South’ that he adopted for the collection of his poetry in PORTAL vol. 5, no. 1, 2008. The Indonesian version, ‘Lembah Elqui, ‘was included in Campbell’s poetry and prose collection Tak ada Peringatan (Vivid Publishing, 2013. In each version now the reference is to Gabriela Mistral (1889-1957, Nobel Prize Laureate for Literature (1945, whose burial place lies in Monte Grande in the Valle de Elqui in northern Chile.

  13. Reticulite‐producing fountains from ring fractures in Kīlauea Caldera ca. 1500 CE: Chapter 16

    Science.gov (United States)

    May, Michael; Carey, Rebecca J.; Swanson, Don; Houghton, Bruce F.; Carey, Rebecca; Cayol, Valérie; Poland, Michael P.; Weis, Dominique

    2015-01-01

    A widely dispersed reticulite bed occurs close to the base of the Keanakākoʻi Tephra at Kīlauea Volcano. It can be divided into six subunits in the northern sector of the volcano; the reticulite also occurs in the southern sector, but outcrops are sparse owing to penecontemporaneous erosion and burial. Multilobate isopachs for each subunit and the total deposit suggest that multiple fountaining vents were distributed in the northern half of the caldera, possibly along ring fractures for the newly formed caldera. Isopach maps also show a sharp decline in thickness along the dispersal axis of each lobe, which could be explained by remobilization of tephra and/or inclined fountains. Despite such isopach characteristics, thinning rates calculated from the isopach data indicate that the fountains were among the most intense and powerful of all studied Kīlauea fountains. Density analyses of the pyroclasts suggest that fountaining was high (>600m) yet complex, possibly due to lava ponding and reentrainment. The calculated volume of the reticulite deposited around the caldera rim is approximately 0.2km3, more voluminous than the deposits of the 1959 Kīlauea Iki eruption; this volume is a minimum, however, as the low-density tephra is easily remobilized, and 600m high caldera walls probably trapped tephra within the caldera, which is deeply buried today and not accounted for in the volume calculations. The duration of this eruption was most likely at least a few days to weeks, based on the calculated volume and estimated discharge rates as seen during the Kīlauea Iki 1959 eruption.

  14. Electrical structure of Plaine des Sables caldera, Piton de la Fournaise volcano (Reunion Island

    Directory of Open Access Journals (Sweden)

    P. A. Schnegg

    1997-06-01

    Full Text Available An Audio Magnetotelluric (AMT profile has been carried out across the Plaine des Sables, a former caldera of the active Piton de la Fournaise volcano, Reunion Island. Located in the Western Indian Ocean, between the Mascarene and Madagascar basins, this basaltic shield volcano originates from the activity of a hot spot. Our aim was to determine the internal structure of the volcano, in particular the shallow electrical properties of an area extending between the old and the new caldera rims. Although several teams had already conducted AMT work in this region a few years ago, there was a need for more a detailed, in depth survey. Our final model displays a noticeable slope of the Plaine des Sables basement oriented toward the present Fournaise summit. This slope is interpreted as resulting from successive landslides toward the ocean. We conclude that this dipping, electrically good conducting layer, probably belongs to the flat layering of an older caldera.

  15. Implications of a Caldera Origin of the Lunar Crater Copernicus

    Science.gov (United States)

    Green, J.

    2007-12-01

    The forthcoming renaissance in lunar exploration will focus on many objectives such as Copernicus. Copernicus appears to be a caldera for at least 8 reasons. If a caldera we see (1) transient activity (2) no overturned impact flap at the crater margins (3) internal sinuous leveed lava flow channels (4) a lava covered floor (5) terraces of different ages (6) multiple central volcanoes, one showing a directed volcanic blast (7) olivine-rich komatiitic lavas on central volcanoes and (8) magmatic inflation/deflation on caldera flanks localizing craterlets and extinct fumaroles in "loop" patterns. Regarding (6), directed volcanic blasts can remove a segment of the volcano wall as evidenced in terrestrial analogs at Mt. St. Helens and Bezymianny. Impact mechanisms to produce this feature in Copernicus are contrived. For (7) Clementine spectral data show a high olivine content of the central mountains on Copernicus which I interpret as forsteritic spinifex mineralization in komatiitic lavas and not as impact rebound of olivine-rich deep seated rocks. (8) MacDonald (1956) documented loop patterns on the flank of Halemaumau in Hawaii defining arcuate fractures localizing fumaroles and craterlets. Inflation/deflation of subjacent magma bodies are interpreted as the cause for these loops. Inflation/deflation mechanisms on caldera flanks are common around terrestrial calderas. "Loop" patterns on the flank of Copernicus localizing "gouge" craterlets have been interpreted as ballistic features resulting from the meteorite impact of this crater. Questioned is the logic of a linear N26E trending array of fragments within Copernicus to serve as a source of ballistic projectiles to form the loops localizing conjugate craterlets. The fused craterlet axes on the lunar loops do not point back to a presumed impact center in Copernicus. The axes are oriented parallel to a regional northwest (N35-60W) fracture zone. Implications for an endogenic origin of Copernicus would involve

  16. Bioethics and Climate Change: A Response to Macpherson and Valles.

    Science.gov (United States)

    Resnik, David B

    2016-10-01

    Two articles published in Bioethics recently have explored the ways that bioethics can contribute to the climate change debate. Cheryl Cox Macpherson argues that bioethicists can play an important role in the climate change debate by helping the public to better understand the values at stake and the trade-offs that must be made in individual and social choices, and Sean Valles claims that bioethicists can contribute to the debate by framing the issues in terms of the public health impacts of climate change. While Macpherson and Valles make valid points concerning a potential role for bioethics in the climate change debate, it is important to recognize that much more than ethical analysis and reflection will be needed to significantly impact public attitudes and government policies. © 2016 John Wiley & Sons Ltd.

  17. Sill intrusion in volcanic calderas: implications for vent opening probability

    Science.gov (United States)

    Giudicepietro, Flora; Macedonio, Giovanni; Martini, Marcello; D'Auria, Luca

    2017-04-01

    Calderas show peculiar behaviors with remarkable dynamic processes, which do not often culminate in eruptions. Observations and studies conducted in recent decades have shown that the most common cause of unrest in the calderas is due to magma intrusion; in particular, the intrusion of sills at shallow depths. Monogenic cones, with large areal dispersion, are quite common in the calderas, suggesting that the susceptibility analysis based on geological features, is not strictly suitable for estimating the vent opening probability in calderas. In general, the opening of a new eruptive vent can be regarded as a rock failure process. The stress field in the rocks that surrounds and tops the magmatic reservoirs plays an important role in causing the rock failure and creating the path that magma can follow towards the surface. In this conceptual framework, we approach the problem of getting clues about the probability of vent opening in volcanic calderas through the study of the stress field produced by the intrusion of magma, in particular, by the intrusion of a sill. We simulate the intrusion of a sill free to expand radially, with shape and dimensions which vary with time. The intrusion process is controlled by the elastic response of the rock plate above the sill, which bends because of the intrusion, and by gravity, that drives the magma towards the zones where the thickness of the sill is smaller. We calculated the stress field in the plate rock above the sill. We found that at the bottom of the rock plate above the sill the maximum intensity of tensile stress is concentrated at the front of the sill and spreads radially with it, over time. For this reason, we think that the front of the spreading sill is prone to open for eruptive vents. Even in the central area of the sill the intensity of stress is relatively high, but at the base of the rock plate stress is compressive. Under isothermal conditions, the stress soon reaches its maximum value (time interval

  18. The Chacana caldera complex in Ecuador

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Minard L; Mothes, Patricia A [Instituto Geofisico, Escuela Politecnica Nacional, Quito (Ecuador)], E-mail: volcan_pete@yahoo.com

    2008-10-01

    The Chacana caldera, located immediately east of Quito, capital of Ecuador, forms the most-northern edifice of Ecuadoros rhyolite province. It is a 50X30 km Pleistocene structure that has remained active into historic times. Vitrophyres, welded tuffs, and ignimbrites of rhyolitic and dacitic composition constitute the outer flanks, meantime syngenetic breccias and tuffs, capped later by extensive dacite lava flows and basin sediments, filled the calderaos depression. A notable resurgence occurred that lifted quiet-water sediments to over 4000 m in elevation. The area has numerous hot springs, and little seismic activity.

  19. The Chacana caldera complex in Ecuador

    International Nuclear Information System (INIS)

    Hall, Minard L; Mothes, Patricia A

    2008-01-01

    The Chacana caldera, located immediately east of Quito, capital of Ecuador, forms the most-northern edifice of Ecuadoros rhyolite province. It is a 50X30 km Pleistocene structure that has remained active into historic times. Vitrophyres, welded tuffs, and ignimbrites of rhyolitic and dacitic composition constitute the outer flanks, meantime syngenetic breccias and tuffs, capped later by extensive dacite lava flows and basin sediments, filled the calderaos depression. A notable resurgence occurred that lifted quiet-water sediments to over 4000 m in elevation. The area has numerous hot springs, and little seismic activity.

  20. Wildfire in the valley of the wild roses

    Science.gov (United States)

    Linda Moon Stumpff

    2015-01-01

    Santa Clara Indian Pueblo lands are adjacent to the Jemez National Forest, Bandelier National Monument and Valles Caldera National Preserve. This paper explores Pueblo vulnerability and resilience after repeated and devastating fires in this century as a result of drought and climate change. Santa Clara Pueblo holds a rich store of traditional knowledge about the fire-...

  1. Fleas, hosts and habitat: What can we predict about the spread of vector-borne zoonotic diseases?

    Science.gov (United States)

    Megan M. Friggens

    2010-01-01

    Vector-borne diseases of humans and wildlife are experiencing resurgence across the globe. I examine the dynamics of flea borne diseases through a comparative analysis of flea literature and analyses of field data collected from three sites in New Mexico: The Sevilleta National Wildlife Refuge, the Sandia Mountains and the Valles Caldera National Preserve (VCNP). My...

  2. Flea abundance, diversity, and plague in Gunnison's prairie dogs (Cynomys gunnisoni) and their burrows in montane grasslands in northern New Mexico

    Science.gov (United States)

    Megan M. Friggens; Robert R. Parmenter; Michael Boyden; Paulette L. Ford; Kenneth Gage; Paul Keim

    2010-01-01

    Plague, a flea-transmitted infectious disease caused by the bacterium Yersinia pestis, is a primary threat to the persistence of prairie dog populations (Cynomys spp.). We conducted a 3-yr survey (2004-2006) of fleas from Gunnison's prairie dogs (Cynomys gunnisoni) and their burrows in montane grasslands in Valles Caldera National Preserve in New Mexico. Our...

  3. Structural controls on the emission of magmatic carbon dioxide gas, Long Valley Caldera, USA

    Science.gov (United States)

    Lucic, Gregor; Stix, John; Wing, Boswell

    2015-04-01

    We present a degassing study of Long Valley Caldera that explores the structural controls upon emissions of magmatic carbon dioxide gas. A total of 223 soil gas samples were collected and analyzed for stable carbon isotopes using a field-portable cavity ring-down spectrometer. This novel technique is flexible, accurate, and provides sampling feedback on a daily basis. Sampling sites included major and minor volcanic centers, regional throughgoing faults, caldera-related structures, zones of elevated seismicity, and zones of past and present hydrothermal activity. The classification of soil gases based on their δ13C and CO2 values reveals a mixing relationship among three end-members: atmospheric, biogenic, and magmatic. Signatures dominated by biogenic contributions (~4 vol %, -24‰) are found on the caldera floor, the interior of the resurgent dome, and areas associated with the Hilton Creek and Hartley Springs fault systems. With the introduction of the magmatic component (~100 vol %, -4.5‰), samples acquire mixing and hydrothermal signatures and are spatially associated with the central caldera and Mammoth Mountain. In particular, they are concentrated along the southern margin of the resurgent dome where the interplay between resurgence-related reverse faulting and a bend in the regional fault system has created a highly permeable fracture network, suitable for the formation of shallow hydrothermal systems. This contrasts with the south moat, where despite elevated seismicity, a thick sedimentary cover has formed an impermeable cap, inhibiting the ascent of fluids and gases to the surface.

  4. Fault structure and kinematics of the Long Valley Caldera region, California, revealed by high-accuracy earthquake hypocenters and focal mechanism stress inversions

    Science.gov (United States)

    Prejean, Stephanie; Ellsworth, William L.; Zoback, Mark; Waldhauser, Felix

    2002-01-01

    We have determined high-resolution hypocenters for 45,000+ earthquakes that occurred between 1980 and 2000 in the Long Valley caldera area using a double-difference earthquake location algorithm and routinely determined arrival times. The locations reveal numerous discrete fault planes in the southern caldera and adjacent Sierra Nevada block (SNB). Intracaldera faults include a series of east/west-striking right-lateral strike-slip faults beneath the caldera's south moat and a series of more northerly striking strike-slip/normal faults beneath the caldera's resurgent dome. Seismicity in the SNB south of the caldera is confined to a crustal block bounded on the west by an east-dipping oblique normal fault and on the east by the Hilton Creek fault. Two NE-striking left-lateral strike-slip faults are responsible for most seismicity within this block. To understand better the stresses driving seismicity, we performed stress inversions using focal mechanisms with 50 or more first motions. This analysis reveals that the least principal stress direction systematically rotates across the studied region, from NE to SW in the caldera's south moat to WNW-ESE in Round Valley, 25 km to the SE. Because WNW-ESE extension is characteristic of the western boundary of the Basin and Range province, caldera area stresses appear to be locally perturbed. This stress perturbation does not seem to result from magma chamber inflation but may be related to the significant (???20 km) left step in the locus of extension along the Sierra Nevada/Basin and Range province boundary. This implies that regional-scale tectonic processes are driving seismic deformation in the Long Valley caldera.

  5. Structure and evolution of an active resurgent dome evidenced by geophysical investigations: The Yenkahe dome-Yasur volcano system (Siwi caldera, Vanuatu)

    Science.gov (United States)

    Brothelande, E.; Lénat, J.-F.; Chaput, M.; Gailler, L.; Finizola, A.; Dumont, S.; Peltier, A.; Bachèlery, P.; Barde-Cabusson, S.; Byrdina, S.; Menny, P.; Colonge, J.; Douillet, G. A.; Letort, J.; Letourneur, L.; Merle, O.; Di Gangi, F.; Nakedau, D.; Garaebiti, E.

    2016-08-01

    In this contribution, we focus on one of the most active resurgences on Earth, that of the Yenkahe dome in the Siwi caldera (Tanna Island, Vanuatu), which is associated with the persistently active Yasur volcano. Gravity and magnetic surveys have been carried out over the past few years in the area, as well as electrical methods including electrical resistivity tomography (ERT), time domain electro-magnetics (TDEM) and self-potential (SP). These investigations were completed by thermometry, CO2 soil gas measurements, field observations and sampling. This multi-method approach allows geological structures within the caldera to be identified, as well as associated hydrothermal features. The global structure of the caldera is deduced from gravity data, which shows the caldera rim as a high density structure. Large lava fields, emplaced before and after the onset of resurgence, are evidenced by combined gravity, magnetic and resistivity signals. In the middle of the caldera, the Yenkahe dome apparently results from a combination of volcanic and tectonic events, showing that lava extrusion and resurgence have been operating simultaneously or alternately during the Siwi caldera post-collapse history. There is a clear distinction between the western and eastern parts of the dome. The western part is older and records the growth of an initial volcanic cone and the formation of a small caldera. This small caldera (paleo-Yasur caldera), partially filled with lava flows, is the present-day focus of volcanic activity and associated fluid circulation and alteration. The eastern part of the dome is presumably younger, and is characterized by intense, extensive hydrothermal alteration and activity. Its northern part is covered by lava flow piles and exhibits a shallow hydrothermal zone in ERT. The southern part has hydrothermal alteration and activity extending at least down to the base of the resurgent dome. This part of the dome is built up of low cohesion rock and is thus

  6. A Physical Model of Sill Expansion to Explain the Dynamics of Unrest at Calderas with Application to Campi Flegrei

    Directory of Open Access Journals (Sweden)

    Flora Giudicepietro

    2017-07-01

    Full Text Available Many calderas show remarkable unrest, which often does not culminate in eruptions (non-eruptive unrest. In this context the interpretation of the geophysical data collected by the monitoring networks is difficult. When the unrest is eruptive, a vent opening process occurs, which leads to an eruption. In calderas, vent locations typically are scattered over a large area and monogenic cones form. The resulting pattern is characterized by a wide dispersion of eruptive vents, therefore, the location of the future vent is not easily predictable. We propose an interpretation of the deformation associated to unrest and vent pattern commonly observed at calderas, based on a physical model that simulates the intrusion and the expansion of a sill. The model can explain both the uplift and any subsequent subsidence through a single process. Considering that the stress mainly controls the vent opening process, we try to gain insight on the vent opening in calderas through the study of the stress field produced by the intrusion of an expanding sill. We find that the tensile stress in the rock above the sill is concentrated at the sill edge in a ring-shaped area with radius depending on the physical properties of magma and rock, the feeding rate and the magma cooling rate. This stress field is consistent with widely dispersed eruptive vents and monogenic cone formation, which are often observed in the calderas. However, considering the mechanical properties of the elastic plate and the rheology of magma, we show that remarkable deformations may be associated with low values of stress in the rock at the top of the intrusion, thereby resulting in non-eruptive unrest. Moreover, we have found that, under the assumption of isothermal conditions, the stress values decrease over time during the intrusion process. This result may explain why the long-term unrest, in general, do not culminate in an eruption. The proposed approach concerns a general process and is

  7. California's restless giant: the Long Valley Caldera

    Science.gov (United States)

    Hill, David P.; Bailey, Roy A.; Hendley, James W.; Stauffer, Peter H.; Marcaida, Mae

    2014-01-01

    Scientists have monitored geologic unrest in the Long Valley, California, area since 1980. In that year, following a swarm of strong earthquakes, they discovered that the central part of the Long Valley Caldera had begun actively rising. Unrest in the area persists today. The U.S. Geological Survey (USGS) continues to provide the public and civil authorities with current information on the volcanic hazard at Long Valley and is prepared to give timely warnings of any impending eruption.

  8. Zeolites of the Valle Central of Costa Rica and its outskirts; Zeolitas del Valle Central de Costa Rica y sus alrededores

    Energy Technology Data Exchange (ETDEWEB)

    Zeledon, Luis Alonso [Moravia, San Jose, (Costa Rica)

    2004-12-15

    19 different species of zeolites have been found in 25 outcrops in the Valle Central of Costa Rica and in the Siquirres region. All the zeolites are secondary minerals and crystallized in little veins and vesicles of the basalts and pyroclastics rocks of the La Cruz and Grifo Alto formations, belonging to the Aguacate Group and the alkaline igneous rocks of Guayacan. The most frequent species of zeolites are stibnite, chabasite, laumontite, mesolite/mordenite, thomsonite, and analcime. Natrolite only was found near to Siquirres. (Author) [Spanish] Se describen 19 especies diferentes de zeolitas procedentes de 25 afloramientos en los alrededores del Valle Central de Costa Rica y en la region de Siquirres. Todas las zeolitas descritas son de origen secundario y se presentan en vetillas y vesiculas de los basaltos y rocas piroclasticas de las formaciones La Cruz y Grifo Alto del Grupo Aguacate y en las rocas igneas alcalinas de Guayacan. Las especies mas frecuentes son estilbita, chabasita, laumontita, mesolita/modernita, thomsonita y analcima. La natrolita solo se encontro en los alrededores de Siquirres. (Autor)

  9. Stratigraphy of the layered terrain in Valles Marineris, Mars

    Science.gov (United States)

    Komatsu, G.; Strom, Roger G.

    1991-01-01

    The layered terrain in Valles Marineris provides information about its origin and the geologic history of this canyon system. Whether the terrain is sedimentary material deposited in a dry or lacustrine environment, or volcanic material related to the tectonics of the canyon is still controversial. However, recent studies of Gangis Layered Terrain suggests a cyclic sequence of deposition and erosion under episodic lacustrine conditions. The stratigraphic studies are extended to four other occurrences of layered terrains in Valles Marineris in an attempt to correlate and distinguish between depositional environments. The Juvantae Chasma, Hebes Chasma, Ophir and Candor Chasmata, Melas Chasma, and Gangis Layered Terrain were examined. Although there are broad similarities among the layered terrains, no two deposits are exactly alike. This suggests that there was no synchronized regional depositional processes to form all the layered deposits. However, the similar erosional style of the lower massive weakly bedded unit in Hebes, Gangis, and Ophir-Candor suggests it may have been deposited under similar circumstances.

  10. niñez en el valle del cauca (Colombia

    Directory of Open Access Journals (Sweden)

    Luis Fernando Aguado Quintero

    2007-01-01

    Full Text Available Se construye un Indicador de Carencias en la Niñez (icn para los 42 municipios que integran el departamento del Valle del Cauca. El índice agrupa un conjunto de indicadores en áreas sensibles al bienestar de la población menor de 15 años de edad: asistencia escolar, cobertura de aseguramiento en la atención de servicios de salud y déficit cualitativo de la vivienda. Los principales resultados muestran que la brecha de carencias infantiles más grande la presenta el municipio de Buenaventura, con un icn de 0.40 y la menor la reporta el municipio de Cali (0.17. Igualmente, con respecto al acceso a servicios sociales básicos para los niños, se hace evidente la gran distancia entre la capital y el promedio departamental, y entre éste último y los municipios más rezagados que conforman la subregión norte del departamento del Valle del Cauca.

  11. Intrapopulational genic variation of the giant African Snail (Achatina fulica in the Valle del Cauca

    Directory of Open Access Journals (Sweden)

    Angie Patiño-Montoya

    2017-05-01

    Full Text Available Objective. To evaluate the intrapopulation genetic variation of A. fulica in the Valle del Cauca. Materials and methods. Ten microsatellite loci from specimens collected at eight municipalities in the Valle del Cauca Department were amplified. Allelic frequencies and descriptors of intrapopulation genetic diversity were estimated. Bayesian analysis was used to estimate the number of groups present in the study area. Results. Two groups were identified in the Valle del Cauca (p > 50%: one group comprised individuals from the north and center of the department, and one group comprised individuals from the south and west of the department. These groups were genetically different from each other (FST 0.16; p<0.05. Isolation by distance was confirmed (Mantel p 0.01; R2 0.06, and a high level of endogamy was detected through a deficit of heterozygotes in the evaluated loci (FIS 0.45. Conclusions. We suggest that the A. fulica population present in the Valle del Cauca could have been introduced at more than one location, or that there could have been more than one wave of invasion. The high level of endogamy is probably the result of control activities that eliminated adult individuals in the population, which has led to an enhanced founder effect.

  12. Vesuvius, the Tengger Mountains and the problem of calderas

    NARCIS (Netherlands)

    Escher, B.G.

    1926-01-01

    Until recently there was no good general map of the Tengger Mountains, so that in 1914 F. von Wolff (bibl. 1) in his work „Der Vulkanismus”, vol. I, p. 510—511, gives a reproduction of Pr. Junghuhn's map of 1844. For a volcanic district that has frequently been used as an example of a caldera and

  13. Vaya valle: "Aquellas escuelas olvidadas"

    Directory of Open Access Journals (Sweden)

    Consuelo Olea Cuena

    2010-12-01

    Full Text Available (ES El "CEIP Virgen de la Velilla" es una escuela situada en la zona Sur de Cantabria, en el municipio de Valderredible. En ella, hemos desarrollado "Vaya valle: Aquellas Escuelas Olvidadas" que se trata de un proyecto anual en el que todas las personas de la escuela, cada una a su nivel, investigan para saber qué ha sucedido con las antiguas escuelas que tenemos desperdigadas por los pueblos. En tiempos de nuestros abuelos y padres, había una o dos escuelas en la mayor parte de los 52 pueblos del valle. De manera que hemos ido de escuela en escuela para escuchar y tomar nota de cómo era el día a día en todas esas escuelas. Ello siempre a través de diferentes relatos en boca de nuestros padres, de nuestros abuelos, o de otras personas que nos hemos encontrado en los pueblos. El alumnado pudo observar cómo eran los edificios, comprobó cual es su estado actual y la función que desempeñan hoy día. Hemos respirado el polvo de los materiales que nos íbamos encontrando, jugando a los juegos que jugaban entonces, escuchando algunas historias tradicionales, e imaginando las situaciones anecdóticas que nos narraban. Con un final más o menos triste, esas escuelas han ido haciéndose más y más pequeñas, hasta llegar a olvidarse tras las concentraciones escolares. Mediante este artículo explicativo, nos gustaría compartir con vosotros nuestra experiencia a nivel pedagógico y organizativo.

  14. The Role of Tectonic Stress in Triggering Large Silicic Caldera Eruptions

    Science.gov (United States)

    Cabaniss, Haley E.; Gregg, Patricia M.; Grosfils, Eric B.

    2018-05-01

    We utilize 3-D temperature-dependent viscoelastic finite element models to investigate the mechanical response of the host rock supporting large caldera-size magma reservoirs (volumes >102 km3) to local tectonic stresses. The mechanical stability of the host rock is used to determine the maximum predicted repose intervals and magma flux rates that systems may experience before successive eruption is triggered. Numerical results indicate that regional extension decreases the stability of the roof rock overlying a magma reservoir, thereby promoting early-onset caldera collapse. Alternatively, moderate amounts of compression (≤10 mm/year) on relatively short timescales (stresses on reservoir stability, our models indicate that the process of rejuvenation and mechanical failure is likely to take place over short time periods of hundreds to thousands of years. These findings support the short preeruption melt accumulation timescales indicated by U series disequilibrium studies.

  15. Geological Evidences for a Large Tsunami Generated by the 7.3 ka Kikai Caldera Eruption, Southern Japan

    Science.gov (United States)

    Yamada, M.; Fujino, S.; Satake, K.

    2017-12-01

    The 7.3 ka eruption of Kikai volcano, southern Kyushu, Japan, is one of the largest caldera-forming eruption in the world. Given that a huge caldera was formed in shallow sea area during the eruption, a tsunami must have been generated by a sea-level change associated. Pyroclastic flow and tsunami deposits by the eruption have been studied around the caldera, but they are not enough to evaluate the tsunami size. The goal of this study is to unravel sizes of tsunami and triggering caldera collapse by numerical simulations based on a widely-distributed tsunami deposit associated with the eruption. In this presentation, we will provide an initial data on distribution of the 7.3 ka tsunami deposit contained in sediment cores taken at three coastal lowlands in Wakayama, Tokushima, and Oita prefectures (560 km, 520 km, and 310 km north-east from the caldera, respectively). A volcanic ash from the eruption (Kikai Akahoya tephra: K-Ah) is evident in organic-rich muddy sedimentary sequence in all sediment cores. Up to 6-cm-thick sand layer, characterized by a grading structure and sharp bed boundary with lower mud, is observed immediately beneath the K-Ah tephra in all study sites. These sedimentary characteristics and broad distribution indicate that the sand layer was most likely deposited by a tsunami which can propagate to a wide area, but not by a local storm surge. Furthermore, the stratigraphic relationship implies that the study sites must have been inundated by the tsunami prior to the ash fall. A sand layer is also evident within the K-Ah tephra layer, suggesting that the sand layer was probably formed by a subsequent tsunami wave during the ash fall. These geological evidences for the 7.3 ka tsunami inundation will contribute to a better understanding of the caldera collapse and the resultant tsunami, but also of the tsunami generating system in the eruptive process.

  16. Plantilla 1: El documento audiovisual: elementos importantes

    OpenAIRE

    Alemany, Dolores

    2011-01-01

    Concepto de documento audiovisual y de documentación audiovisual, profundizando en la distinción de documentación de imagen en movimiento con posible incorporación de sonido frente al concepto de documentación audiovisual según plantea Jorge Caldera. Diferenciación entre documentos audiovisuales, obras audiovisuales y patrimonio audiovisual según Félix del Valle.

  17. Evaluación de los programas de control prenatal para adolescentes en el valle de Aburrá, 2003 Evaluation of prenatal control programs offered to teenagers in Valle de Aburrá, Colombia, 2003

    OpenAIRE

    Carlos Adolfo Salazar; Margarita María Ortiz Mesa; María Isabel Martínez Ortiz; Andrea González Morales; Joaquín Guillermo Gómez Dávila

    2004-01-01

    Objetivo: la investigación que se presenta a continuación tuvo como objetivo identificar y evaluar los programas de control prenatal para adolescentes ofrecidos en el valle de Aburrá, Antioquia, Colombia, durante el año 2003. Materiales y métodos: se revisaron varias fuentes primarias y se elaboró un listado de todas las instituciones de salud del valle de Aburrá. Se hicieron entrevistas telefónicas con los respectivos directores para establecer cuáles instituciones tenían un programa de cont...

  18. En reise i tid og landskap – Planlegging og tilrettelegging i kulturlandskapet, Valle i Setesdal

    OpenAIRE

    Hillestad, Ingunn

    2010-01-01

    Oppgaven omhandler hvordan fremtidig utvikling i Valle i Setesdal kan legges tilrette gjennom lansdskapsplanlegging. Selve initiativet kom fra Valle kommune, men jeg har stått fritt i forhold til vinklingen av oppgaven. Målet er å aktivisere Nomeland, et sentrumsnært område og omkringliggende steder. Planleggingen skal rettes mot friluftsliv og kultur. Et annet mål er å få en bred og sammensatt brukergruppe, med forankring i lokalbefolkningen og et tilbud for turister. Oppgaven er strukturert...

  19. Estudio hidrogeológico del valle de Mala

    OpenAIRE

    Ministerio de Agricultura. Dirección General de Aguas, Suelos e Irrigaciones

    1980-01-01

    Determina el recurso hídrico subterráneo del valle del río Mala, mediante el análisis e investigación de las características hidrogeológicas, en base a las informaciones de diferentes etapas del estudio; para de esta manera, racionalizar mejor su uso, dando cumplimiento así a lo dispuesto por la Ley General de Aguas.

  20. Popkultuurgi on rahvuskultuuri osa / Valle-Sten Maiste ja Jan Kaus

    Index Scriptorium Estoniae

    Maiste, Valle-Sten, 1972-

    2009-01-01

    Õnnestunud muusikafestival Tallinn Music Week tõstatas olulisi kultuuripoliitilisi küsimusi. Jan Kaus ja Valle-Sten Maiste arutlevad artiklis selle üle, et popkultuur vajaks hariduse ja tugistruktuuride näol toestamist, tuleks tunnustada kodumaist väärt pop- ja rockmuusikat

  1. Radionuclides in hydrothermal systems as indicators of repository conditions

    International Nuclear Information System (INIS)

    Wollenberg, H.A.; Flexser, S.; Smith, A.R.

    1990-11-01

    Hydrothermal systems in tuffaceous and older sedimentary rocks contain evidence of the interaction of radionuclides in fluids with rock matrix minerals and with materials lining fractures, in settings somewhat analogous to the candidate repository site at Yucca Mountain, NV. Earlier studies encompassed the occurrences of U and Th in a ''fossil'' hydrothermal system in tuffaceous rock of the San Juan Mountains volcanic field, CO. More recent and ongoing studies examine active hydrothermal systems in calderas at Long Valley, CA and Valles, NM. At the Nevada Test Site, occurrences of U and Th in fractured and unfractured rhyolitic tuff that was heated to simulate the introduction of radioactive waste are also under investigation. Observations to date suggest that U is mobile in hydrothermal systems, but that localized reducing environments provided by Fe-rich minerals and/or carbonaceous material concentrate U and thus attenuate its migration. 11 refs., 6 figs., 1 tab

  2. Jurassic ash-flow sheets, calderas, and related intrusions of the Cordilleran volcanic arc in southeastern Arizona: implications for regional tectonics and ore deposits

    Science.gov (United States)

    Lipman, P.W.; Hagstrum, J.T.

    1992-01-01

    Volcanologic, petrologic, and paleomagnetic studies of widespread Jurassic ash-flow sheets in the Huachuca-southern Dragoon Mountains area have led to identification of four large source calderas and associated comagnetic intracaldera intrusions. Stratigraphic, facies, and contact features of the caldera-related tuffs also provide constraints on the locations, lateral displacements, and very existence for some major northwest-trending faults and inferred regional thrusts in southeastern Arizona. Silicic alkalic compositions of the Jurassic caldera-related, ash-flow tuffs; bimodal associated mafic magmatism; and interstratified coarse sedimentary deposits provide evidence for synvolcanic extension and rifting within the Cordilleran magmatic arc. Gold-copper mineralization is associated with subvolcanic intrusions at several of the Jurassic calderas. -from Authors

  3. Caldera formation and varied eruption styles on North Pacific seamounts: the clastic lithofacies record

    Science.gov (United States)

    Portner, Ryan A.; Clague, Dave A.; Paduan, Jennifer B.

    2014-08-01

    Detailed examination of volcaniclastic and sedimentary rocks collected from the Taney (30 Ma), President Jackson (4 Ma), Vance (3 Ma) and Alarcon (2 Ma) near-ridge seamount chains of the North Pacific reveals seven clastic lithofacies that record various modes of eruption, magma fragmentation, and particle dispersal. Lithofacies are distinguished by differences in lithology, bedding habit, compositional heterogeneity, and relationship to volcanic landforms. Breccia lithofacies were produced through mechanical fragmentation during caldera collapse (polymict) or effusive eruptions onto steep slopes (monomict). Rare globular lapilli mudstone lithofacies contain clasts with morphologies formed by magma-sediment mingling processes (peperite). Seamount summit pyroclastic deposits include proximal lapilli tuff with vesicular pyroclasts, and more distal limu o Pele tuff lithofacies. Much finer-grained hydrothermal mudstone/tuff lithofacies occurs around caldera rims and contains greenschist minerals, hydrothermal clays and basaltic ash that record subsurface phreatomagmatic fragmentation processes. Very fine-grained ash is transported to distal regions by oceanic currents and hydrothermal plumes, and is a component of the regional pelagic sediment budget. Pyroclastic lithofacies only occur on seamount summits suggesting formation during the latter stages of seamount evolution. As a seamount drifts away from an adjacent ridge axis and associated heat source, its magma supply is reduced allowing for magmatic gas buildup and mild explosive eruptions. During this stage, the diminished melt supply under the seamount is unable to fully compensate for extension along the ridge axis and vertical seamount growth. Lateral intrusion into spreading-related structures in this stage causes magma withdrawal and caldera formation. Formation of caldera ring faults also promotes seawater ingress into subseafloor hydrothermal cells, which interact with magma conduits causing phreatomagmatic

  4. Decadal to monthly timescales of magma transfer and reservoir growth at a caldera volcano.

    Science.gov (United States)

    Druitt, T H; Costa, F; Deloule, E; Dungan, M; Scaillet, B

    2012-02-01

    Caldera-forming volcanic eruptions are low-frequency, high-impact events capable of discharging tens to thousands of cubic kilometres of magma explosively on timescales of hours to days, with devastating effects on local and global scales. Because no such eruption has been monitored during its long build-up phase, the precursor phenomena are not well understood. Geophysical signals obtained during recent episodes of unrest at calderas such as Yellowstone, USA, and Campi Flegrei, Italy, are difficult to interpret, and the conditions necessary for large eruptions are poorly constrained. Here we present a study of pre-eruptive magmatic processes and their timescales using chemically zoned crystals from the 'Minoan' caldera-forming eruption of Santorini volcano, Greece, which occurred in the late 1600s BC. The results provide insights into how rapidly large silicic systems may pass from a quiescent state to one on the edge of eruption. Despite the large volume of erupted magma (40-60 cubic kilometres), and the 18,000-year gestation period between the Minoan eruption and the previous major eruption, most crystals in the Minoan magma record processes that occurred less than about 100 years before the eruption. Recharge of the magma reservoir by large volumes of silicic magma (and some mafic magma) occurred during the century before eruption, and mixing between different silicic magma batches was still taking place during the final months. Final assembly of large silicic magma reservoirs may occur on timescales that are geologically very short by comparison with the preceding repose period, with major growth phases immediately before eruption. These observations have implications for the monitoring of long-dormant, but potentially active, caldera systems.

  5. Identidades en movimiento: familias chilenas en la fruticultura del Alto Valle de Río Negro, Argentina Identities in movement: chilean families in the fruit production of the Alto Valle de Río Negro, Argentina

    Directory of Open Access Journals (Sweden)

    Verónica Trpin

    2007-12-01

    Full Text Available Este artículo, basado en el trabajo de campo realizado en áreas rurales del Alto Valle de Río Negro, Argentina, desde el año 1999, tiene como propósito presentar las relaciones en las cuales se insertan hombres y mujeres chilenas que residen y trabajan en "chacras" destinadas a la producción frutícola. Las diferentes actividades en las chacras se organizan según el sexo y la edad, definiéndose una segmentación del mercado de trabajo en la que se ven involucrados los diferentes miembros de la familia. Como desarrollaré, ser trabajadores chilenos en la fruticultura del Alto Valle de Río Negro reproduce una identidad étnica y nacional en el seno de la cotidianeidad familiar y laboral.This article, based on field work conducted in rural areas of the Alto Valle de Río Negro, Argentina, from 1999 on, analyzes the relations in which Chilean men and women who reside and work in small farms destined to fruit production are inserted. The different activities in the small farms are organized according to sex and age, circumscribing a segment of the labor market in which different members of the family are involved. As I will demonstrate, to be a Chilean worker in the fruit growing region of the Alto Valle is to reproduce an ethnic and national identity through work routines mediated by family relations.

  6. Caracterización del sector cooperativo de ahorro y crédito en el Valle del Cauca

    Directory of Open Access Journals (Sweden)

    Ximena Sánchez Mayorga

    2008-01-01

    Full Text Available El artículo presenta una caracterización del sector cooperativo de ahorro y crédito en el Valle del Cauca, el cual es uno de los objetivos a desarrollar en el proyecto de investigación "Análisis del sector cooperativo de ahorro y crédito en el Valle del Cauca y propuesta de estrategia. Caso Cooperativa de Ahorro del Valle", del Grupo de Investigación Gestión y Productividad Contable. El estudio muestra la dinámica de crecimiento que ha tenido el sector cooperativo de ahorro y crédito en el Valle del Cauca en los últimos cinco años, aportando a la bancarización en Colombia; también se revisa el sector de economía solidaria en Colombia, presentando estadísticas que permiten visualizar lo que representa este sector en la economía del país. Se identifican en el Valle del Cauca las entidades dedicadas a la actividad de ahorro y crédito, planteándose las diferencias entre estas entidades y los establecimientos bancarios del sector financiero tradicional, resaltando el aporte de las cooperativas de ahorro y crédito a la estrategia del Gobierno Nacional definida como la banca de oportunidades1; puesto que en estas entidades hay igualdad social para sus asociados, logrando que un mayor número de personas accedan a los servicios financieros, aportando al desarrollo económico de las localidades donde funcionan.

  7. CONSIDERACIONES SOBRE LAS ALGAS DEL VALLE DE TEHUACÁN-CUICATLÁN

    Directory of Open Access Journals (Sweden)

    Eberto Novelo

    2012-01-01

    Full Text Available El Valle de Tehuacán-Cuicatlán es una zona semiárida que presenta una flora de algas rica en los cuerpos de agua temporales y permanentes, consta de 357 especies, muchas de ellas no registradas previamente en México: 183 especies de Bacillariophyta representan cerca del 50 % de la flora; 81 especies de Cyanoprokaryota constituyen el 22 % de la misma, 77 especies de Chlorophyta aportan el 20 % de la riqueza; complementan la flora 10 especies de Euglenophyta (2.8 %, 5 especies de Heterokontophyta (1.4 % y una especie de Rhodophyta (0.2 %. Las especies más frecuentes y más ampliamente distribuidas son en su mayoría alcalífilas y eurihalobias. Sin embargo, la mayoría de las especies se distribuyen principalmente en una o dos localidades y en dos tipos de ambientes (canales de riego y charcos. Se discute sobre la heterogeneidad de la composición tomando en cuenta la frecuencia de aparición en las muestras y en las cuatro zonas del Valle y el significado de esa distribución. El análisis de distribución y dominancia de las especies sugiere que las condiciones acuáticas del Valle son muy cambiantes y ello promueve la proliferación de especies de un espectro ecológico amplio, dentro de los límites generales de alcalinidad y salinidad moderadas.

  8. Herencia materna en poblaciones de Puna y Valle Calchaqui - Salta

    Directory of Open Access Journals (Sweden)

    Albeza, María V.

    2005-01-01

    Full Text Available Las poblaciones de la Puna y el Valle Calchaquí han sido estudiadas, tanto desde la perspectiva demográfica como de marcadores genéticos clásicos y nucleares. En este trabajo se analizan las secuencias de la región hipervariable I del mtDNA, en muestras de 100 individuos de diferentes localidades. La zona comprendida entre las posiciones 15997-16400 según la secuencia Anderson (región hipervariable I-HVRI fue secuenciada. El motivo RFLP- 7025 AluI fue adicionalmente analizado en las muestras para determinar su inclusión dentro del haplogrupo H. Las muestras que resultaron no-H fueron asignadas a distintos haplogrupos. Se han detectado un total de 34 haplotipos distintos definidos por 50 posiciones variables de los que una muy baja proporción (13,1 % resultaron haplotipos únicos. Sólo 4 de los 34 haplotipos son compartidos entre la población de la Puna y la de los Valles.

  9. Comparative mortality patterns among the black population and the white-mestizo in Cali and Valle

    Directory of Open Access Journals (Sweden)

    Fernando Urrea-Giraldo

    2015-08-01

    Full Text Available The article analyzes the patterns of comparative mortality of Cali and Valle, between the Afrodescendant and white-mestizo population, by sex and age groups, based on the metadata of deaths in the 2005 Census and the death certificate of the year 2010. The findings reveal strong differentials by age structures of deaths (pyramids and the cumulative mortality, which are conclusive of unequal mortality patterns between the two populations, both in Cali and Valle. This evinces demography of social inequality based on ethnic-racial component.

  10. DIAGNÓSTICO Y PROPUESTA PARA UNA GESTIÓN INTEGRAL DEL RIESGO EN EL VALLE DE ABURRA: RED RIESGOS

    Directory of Open Access Journals (Sweden)

    ARISTIZÁBAL EDIER

    2010-05-01

    Full Text Available A partir del análisis de la situación organizacional de las diferentes instituciones en el Valle de Aburrá frente a la reducción de desastres y emergencias asociadas con los fenómenos de origen natural y antrópico, el Área Metropolitana del Valle de Aburrá, como autoridad ambiental y entidad planificadora, hace una propuesta que pretende articular todas las entidades, organizaciones e instituciones públicas y privadas hacia una gestión integral del riesgo, y la cual denominó: Red para la Gestión del Riesgo en el Valle de Aburrá, Red Riesgos. Red Riesgos es un sistema organizacional abierto de carácter interinstitucional para orientar y coordinar las políticas y acciones de análisis y reducción de riesgos, preparación y ejecución de la respuesta y recuperación en casos de desastre y emergencias en el Valle de Aburrá. Como instrumento estratégico de la Red, se formuló el Plan Regional para la Gestión del Riesgo en el Valle de Aburrá que contiene las acciones que se deben ejecutar para la reducción de desastres y el manejo óptimo de los mismos y se diseñó el Sistema Integrado de Información para dar soporte a los diferentes procesos de gestión de la Red.

  11. A three-dimensional QP imaging of the shallowest subsurface of Campi Flegrei offshore caldera, southern Italy

    Science.gov (United States)

    Serlenga, Vincenzo; de Lorenzo, Salvatore; Russo, Guido; Amoroso, Ortensia; Virieux, Jean; Garambois, Stephane; Zollo, Aldo

    2017-04-01

    We build a three-dimensional attenuation image of the shallowest subsurface of Campi Flegrei caldera, a resurgent caldera located 15 km west of Naples, southern Italy. Extracting tstar (t*) measurements from an active seismic dataset can be achieved by a spectral ratio method which has been intensively used for earthquakes. The applicability of such measurement has to be validated for active seismic datasets which have a narrower frequency band compared to frequency band of quakes. The validation, as well as the robustness, of such extraction for narrow Ricker source wavelet has been checked through many synthetic and realistic tests. These tests allow us to conclude that this measurement is valid as long as 1) short signal time window are chosen to perform the spectral analysis; 2) the effects caused by heterogeneities of the sampled medium on the seismic spectra have to be taken into account in the description of elastic Green's function. Through such a deconvolution strategy, contributions of the fine velocity structure on signal amplitudes have been significantly removed: in case of suspicious behavior of the spectrum ratio, the measurement is disregarded. This procedure, a kind of deconvolution of the phase propagation imprint, is expected to leave nearly untouched the attenuation signature of seismic traces we are interested in. Such refined measurement approach based on the spectral ratio method has been applied to the real active seismic SERAPIS database providing us a reasonable dataset of 11,873 differential t* measurements (dt*). These data are used for imaging anelastic properties of Campi Flegrei caldera through a linearized, iterative, damped attenuation tomography. Based on configuration of sources and receivers, an attenuating volume as large as 13 x 13 x 1.5 km3 has been imaged. The tomography, with a resolution of 1 km in the horizontal directions and 0.5 km in the vertical direction, allowed to image important features whose reliability has been

  12. Renewed inflation of Long Valley Caldera, California (2011 to 2014)

    Science.gov (United States)

    Montgomery-Brown, Emily; Wicks, Chuck; Cervelli, Peter F.; Langbein, John O.; Svarc, Jerry L.; Shelly, David R.; Hill, David P.; Lisowski, Michael

    2015-01-01

    Slow inflation began at Long Valley Caldera in late 2011, coinciding with renewed swarm seismicity. Ongoing deformation is concentrated within the caldera. We analyze this deformation using a combination of GPS and InSAR (TerraSAR-X) data processed with a persistent scatterer technique. The extension rate of the dome-crossing baseline during this episode (CA99 to KRAC) is 1 cm/yr, similar to past inflation episodes (1990–1995 and 2002–2003), and about a tenth of the peak rate observed during the 1997 unrest. The current deformation is well modeled by the inflation of a prolate spheroidal magma reservoir ∼7 km beneath the resurgent dome, with a volume change of ∼6 × 106 m3/yr from 2011.7 through the end of 2014. The current data cannot resolve a second source, which was required to model the 1997 episode. This source appears to be in the same region as previous inflation episodes, suggesting a persistent reservoir.

  13. Interpreting compositional zonation of the Zaragoza ignimbrite from Los Humeros caldera, Central Mexico

    International Nuclear Information System (INIS)

    Carrasco-Nunez, Gerardo; McCurry, Michael; Branney, Michael J

    2008-01-01

    Compositional zonation in ignimbrites is relatively common, and is often inferred to record gradual withdrawal by an eruption of a density-stratified magma chamber (with silicic magma towards the top and more dense, mafic magma at the bottom). We show that this model does not match observations at the ca. 0.1 Ma Zaragoza ignimbrite from Los Humeros caldera in central Mexico. Detailed petrologic studies reveal a more complex scenario: the ignimbrite exhibits a 'double' vertical zonation based on the compositions of pumice lapilli. We present evidence for mingling and limited mixing occurred during or immediately before the caldera-forming eruption. One possibility to explain the observations is that the ignimbrite eruption occurred in response to intrusion of a hybridized andesitic magma into a rhyodacitic magma chamber.

  14. Surface heat flow density at the Phlegrean Fields caldera (southern Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Corrado, Gennardo [Naples Univ., Dept. of Geophysics and Volcanology, Naples (Italy); De Lorenzo, Salvatore; Mongelli, Francesco; Tramacere, Antonio; Zito, Gianmaria [Bari Univ., Dept. of Geology and Geophysics, Bari (Italy)

    1998-08-01

    The Phlegrean Fields areas is a Holocene caldera located west of Naples, southern Italy. The recent post caldera activity is characterised by several eruptive centers inside the collapsed areas. In order to investigate the still active volcanic processes, surface heat flow measurement were carried out in 1995 in 30 sites of the Phlegrean Fields and a heat flow map compiled. Filtering of the map reveals some well-defined anomalies superimposed on a general southward-increasing trend. Local anomalies are related to small magma bodies, whereas the observed general trend has been attributed to the effect of ground-water flow. This effect was calculated and removed. The undisturbed mean value of the surface heat flow density in the eastern sector is 149mW/m{sup 2}, which is above the regional value of 85mW/m{sup 2} assigned to the eastern part of the Tyrrhenian Sea, and which is probably influenced by a very large, deep magmatic body. (Author)

  15. Geotrail development to connect the dots in Muara Caldera Toba, Indonesia

    Science.gov (United States)

    Ginting, Nurlisa; Siregar, Narosu

    2018-03-01

    The growth of awareness in sustainable tourism has led to the development of geotourism all around the world, in which geotourism promotes conservation of geoheritage, appreciation of geosites, and interpretation of geoscience. The Toba Caldera in Indonesia is a genuine evidence of geological phenomena, and at present, the remaining geosites in its surrounding are potential as the tourism attraction. Previous works on geotourism have shown several perspectives in geology, however, research for geotourism planning in destinations is limited. Using the principle of tourism attraction, this paper introduces geotrail concept by connecting the values of each geosite in the Toba Caldera, particularly in Muara. Through qualitative approach, the prospect of initiating a geotrail in Muara is explored using panels, viewpoints, timeline, and stops. Collected data from observations and interviews were analysed with triangular method. The result indicates that natural element is dominant, built element can complement the nature, and it is suggested to strengthen cultural and social elements to optimize the geotrail development.

  16. Distributed-Temperature-Sensing Using Optical Methods: A First Application in the Offshore Area of Campi Flegrei Caldera (Southern Italy for Volcano Monitoring

    Directory of Open Access Journals (Sweden)

    Stefano Carlino

    2016-08-01

    Full Text Available A temperature profile 2400 m along the off-shore active caldera of Campi Flegrei (Gulf of Pozzuoli was obtained by the installation of a permanent fiber-optic monitoring system within the framework of the Innovative Monitoring for Coastal and Marine Environment (MON.I.C.A project. The system consists of a submerged, reinforced, multi-fiber cable containing six single-mode telecom grade optical fibers that, exploiting the stimulated Brillouin scattering, provide distributed temperature sensing (DTS with 1 m of spatial resolution. The obtained data show that the offshore caldera, at least along the monitored profile, has many points of heat discharge associated with fluid emission. A loose association between the temperature profile and the main structural features of the offshore caldera was also evidenced by comparing DTS data with a high-resolution reflection seismic survey. This represents an important advancement in the monitoring of this high-risk volcanic area, since temperature variations are among the precursors of magma migration towards the surface and are also crucial data in the study of caldera dynamics. The adopted system can also be applied to many other calderas which are often partially or largely submerged and hence difficult to monitor.

  17. The origin of a coarse lithic breccia in the 34 ka caldera-forming Sounkyo eruption, Taisetsu volcano group, central Hokkaido, Japan

    Science.gov (United States)

    Yasuda, Y.; Suzuki-Kamata, K.

    2018-05-01

    The 34 ka Sounkyo eruption produced 7.6 km3 of tephra ( 5 km3 DRE) as fallout, ignimbrite, and lithic breccia units, forming a small, 2-km-diameter summit caldera in the Taisetsu volcano group, Japan. The Sounkyo eruption products are made up of five eruptive units (SK-A to -E) in proximal regions, corresponding to the distal deposits, a 1- to 2-m-thick pumice fallout and the Px-type ignimbrite up to 220 m thick. The eruption began with a fallout phase, producing unstable low eruption columns during the earlier phase to form a 27-m-thick, unstratified and ungraded, coarse lithic breccia (SK-C). The failure in turn choked the conduit, and then the eruption stopped. After a short eruptive hiatus, the eruption resumed with a short-lived fall phase, establishing an eruption column up to 16 km high and producing a <6-m-thick scoria fallout (SK-D). Finally, the eruption ended with the generation of PDCs by eruption column collapse to form a 5- to 15-m-thick ignimbrite in the proximal area (SK-E). Volume relationships between the caldera, ejected magma, and ejected lithic fragments suggest that the caldera was not essentially formed by caldera collapse but, instead, by vent widening as a consequence of explosive erosion and failure of the shallow conduit. The dominance of shallow-origin volcanic rocks in the lithic fraction throughout the Sounkyo eruption products implies the development of a flaring funnel-shaped vent. Hence, the occurrence of lithic breccias within small caldera-forming eruption products does not necessarily reflect either the existence or the timing of caldera collapse, as commonly assumed in literature. Lithic breccias commonly overlie climactic ignimbrite/fallout deposits in small caldera-forming eruptions, and an alternative explanation is that this reflects the collapse of the shallow conduit after an eruption climax, whose walls had been highly fractured and had become unstable owing to progressive erosion.

  18. The Regional Water Cycle and Water Ice Clouds in the Tharsis - Valles Marineris System

    Science.gov (United States)

    Leung, C. W. S.; Rafkin, S. C.

    2017-12-01

    The regional atmospheric circulation on Mars is highly influenced by local topographic gradients. Terrain-following air parcels forced along the slopes of the major Tharsis volcanoes and the steep canyon walls of Valles Marineris significantly impact the local water vapor concentration and the associated conditions for cloud formation. Using a non-hydrostatic mesoscale atmospheric model with aerosol & cloud microphysics, we investigate the meteorological conditions for water ice cloud formation in the coupled Tharsis - Valles Marineris system near the aphelion season. The usage of a limited area regional model ensures that topographic slopes are well resolved compared to the typical resolutions of a global-coverage general circulation model. The effects of shadowing and slope angle geometries on the energy budget is also taken into account. Diurnal slope winds in complex terrains are typically characterized by the reversal of wind direction twice per sol: upslope during the day, and downslope at night. However, our simulation results of the regional circulation and diurnal water cycle indicate substantial asymmetries in the day-night circulation. The convergence of moist air masses enters Valles Marineris via easterly flows, whereas dry air sweep across the plateau of the canyon system from the south towards the north. We emphasize the non-uniform vertical distribution of water vapor in our model results. Water vapor mixing ratios in the lower planetary boundary layer may be factors greater than the mixing ratio aloft. Water ice clouds are important contributors to the climatic forcing on Mars, and their effects on the mesoscale circulations in the Tharsis - Valles Marineris region significantly contribute to the regional perturbations in the large-scale global atmospheric circulation.

  19. Ballistic blocks around Kīlauea Caldera: Their vent locations and number of eruptions in the late 18th century

    Science.gov (United States)

    Swanson, Donald A.; Zolkos, Scott P.; Haravitch, Ben

    2012-01-01

    Thousands of ballistic blocks occur around Kīlauea Caldera and record part of the latest major period of explosive activity on the volcano, in late 1790 or within a few years thereafter. The sizes of the blocks – the largest of which is more than 2 m in nominal diameter – and differences in rock types allow the definition of at least 6 dispersal lobes of mostly undetermined relative age. The orientations of the lobes help approximate the locations of vents or explosion sources on the floor of the caldera, now deeply buried by younger lava flows. The vents may have been distributed northward for about 2 km from near the site of the modern Halema'uma'u Crater and were apparently confined to the western half of the caldera. The blocks are entirely lithic except for those in one dispersal lobe, which contains cored bombs and blocks as well as juvenile lapilli. Eruption parameters calculated from EJECT! suggest that the phreatic and phreatomagmatic explosions could have been generated at the water table, about 600 m below the high point on the caldera rim.

  20. High-resolution aeromagnetic survey of the Mono Basin-Long Valley Caldera region, California

    Science.gov (United States)

    Ponce, D. A.; Mangan, M.; McPhee, D.

    2013-12-01

    A new high-resolution aeromagnetic survey of the Mono Basin-Long Valley Caldera region greatly enhances previous magnetic interpretations that were based on older, low-resolution, and regional aeromagnetic data sets and provides new insights into volcano-tectonic processes. The surveyed area covers a 8,750 km2 NNW-trending swath situated between the Sierra Nevada to the west and the Basin and Range Province to the east. The surveyed area includes the volcanic centers of Mono Lake, Mono-Inyo Craters, Mammoth Mountain, Devils Postpile, and Long Valley Caldera. The NW-trending eastern Sierra frontal fault zone crosses through the study area, including the active Mono Lake, Silver Lake, Hartley Springs, Laurel Creek, and Hilton Creek faults. Over 6,000 line-kilometers of aeromagnetic data were collected at a constant terrain clearance of 150 m, a flight-line spacing of 400 m, and a tie-line spacing of 4 km. Data were collected via helicopter with an attached stinger housing a magnetic sensor using a Scintrex CS-3 cesium magnetometer. In the northern part of the survey area, data improve the magnetic resolution of the individual domes and coulees along Mono Craters and a circular shaped magnetic anomaly that coincides with a poorly defined ring fracture mapped by Kistler (1966). Here, aeromagnetic data combined with other geophysical data suggests that Mono Craters may have preferentially followed a pre-existing plutonic basement feature that may have controlled the sickle shape of the volcanic chain. In the northeastern part of the survey, aeromagnetic data reveal a linear magnetic anomaly that correlates with and extends a mapped fault. In the southern part of the survey, in the Sierra Nevada block just south of Long Valley Caldera, aeromagnetic anomalies correlate with NNW-trending Sierran frontal faults rather than to linear NNE-trends observed in recent seismicity over the last 30 years. These data provide an important framework for the further analysis of the

  1. Peripheral Faulting of Eden Patera: Potential Evidence in Support of a New Volcanic Construct on Mars

    Science.gov (United States)

    Harlow, J.

    2016-12-01

    Arabia Terra's (AT) pock-marked topography in the expansive upland region of Mars Northern Hemisphere has been assumed to be the result of impact crater bombardment. However, examination of several craters by researchers revealed morphologies inconsistent with neighboring craters of similar size and age. These 'craters' share features with terrestrial super-eruption calderas, and are considered a new volcanic construct on Mars called `plains-style' caldera complexes. Eden Patera (EP), located on the northern boundary of AT is a reference type for these calderas. EP lacks well-preserved impact crater morphologies, including a decreasing depth to diameter ratio. Conversely, Eden shares geomorphological attributes with terrestrial caldera complexes such as Valles Caldera (New Mexico): arcuate caldera walls, concentric fracturing/faulting, flat-topped benches, irregular geometric circumferences, etc. This study focuses on peripheral fractures surrounding EP to provide further evidence of calderas within the AT region. Scaled balloon experiments mimicking terrestrial caldera analogs have showcased fracturing/faulting patterns and relationships of caldera systems. These experiments show: 1) radial fracturing (perpendicular to caldera rim) upon inflation, 2) concentric faulting (parallel to sub-parallel to caldera rim) during evacuation, and 3) intersecting radial and concentric peripheral faulting from resurgence. Utilizing Mars Reconnaissance Orbiter Context Camera (CTX) imagery, peripheral fracturing is analyzed using GIS to study variations in peripheral fracture geometries relative to the caldera rim. Visually, concentric fractures dominate within 20 km, radial fractures prevail between 20 and 50 km, followed by gradation into randomly oriented and highly angular intersections in the fretted terrain region. Rose diagrams of orientation relative to north expose uniformly oriented mean regional stresses, but do not illuminate localized caldera stresses. Further

  2. Magnetotelluric Investigations of the Yellowstone Caldera: Understanding the Emplacement of Crustal Magma Bodies

    Science.gov (United States)

    Gurrola, R. M.; Neal, B. A.; Bennington, N. L.; Cronin, R.; Fry, B.; Hart, L.; Imamura, N.; Kelbert, A.; Bowles-martinez, E.; Miller, D. J.; Scholz, K. J.; Schultz, A.

    2017-12-01

    Wideband magnetotellurics (MT) presents an ideal method for imaging conductive shallow magma bodies associated with contemporary Yellowstone-Snake River Plain (YSRP) magmatism. Particularly, how do these magma bodies accumulate in the mid to upper crust underlying the Yellowstone Caldera, and furthermore, what role do hydrothermal fluids play in their ascent? During the summer 2017 field season, two field teams from Oregon State University and the University of Wisconsin-Madison installed forty-four wideband MT stations within and around the caldera, and using data slated for joint 3-D inversion with existing seismic data, two 2-D vertical conductivity sections of the crust and upper mantle were constructed. These models, in turn, provide preliminary insight into the emplacement of crustal magma bodies and hydrothermal processes in the YSRP region.

  3. Interpreting compositional zonation of the Zaragoza ignimbrite from Los Humeros caldera, Central Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Carrasco-Nunez, Gerardo [Centro de Geociencias, UNAM, Campus Juriquilla, Queretaro, Qro. (Mexico); McCurry, Michael [Department of Geology, Idaho State University, Pocatello, ID (United States); Branney, Michael J [Department of Geology, University of Leicester, Leicester (United Kingdom)

    2008-10-01

    Compositional zonation in ignimbrites is relatively common, and is often inferred to record gradual withdrawal by an eruption of a density-stratified magma chamber (with silicic magma towards the top and more dense, mafic magma at the bottom). We show that this model does not match observations at the ca. 0.1 Ma Zaragoza ignimbrite from Los Humeros caldera in central Mexico. Detailed petrologic studies reveal a more complex scenario: the ignimbrite exhibits a 'double' vertical zonation based on the compositions of pumice lapilli. We present evidence for mingling and limited mixing occurred during or immediately before the caldera-forming eruption. One possibility to explain the observations is that the ignimbrite eruption occurred in response to intrusion of a hybridized andesitic magma into a rhyodacitic magma chamber.

  4. Qualité de l’air et nuisances sonores dans les vallées alpines de transit

    Directory of Open Access Journals (Sweden)

    Jürg Thudium

    2009-03-01

    Full Text Available Les conséquences du trafic routier, en termes de nuisances sonores et de qualité de l’air, ont été analysées et comparées pour quatre vallées de transit alpin (Fréjus, Mont Blanc, Gothard et Brenner durant l’année 2004. Au regard du trafic alpin dans son ensemble, des disparités considérables apparaissent entre les vallées étudiées, mais également à l’intérieur de ces mêmes vallées. Les immissions (concentration de polluants produites par unité d’émission du trafic routier sont deux à trois fois plus élevées dans ces vallées alpines qu’en plaine. Ceci s’explique principalement par la topographie et le climat particuliers de ces vallées. À de nombreux points d’observation, les seuils d’immission ont été dépassés. Les vallées sont également affectées durement par la pollution sonore. « L’effet amphithéâtre » transporte le bruit à des altitudes supérieures, qui n’auraient pas été exposées à autant d’irradiation acoustique si la source de nuisances était située à égale distance, mais dans un « paysage ouvert ». De plus, la protection contre le bruit qui se réfléchit sur les pentes est malaisée. En résumé, toutes les vallées de transit étudiées peuvent être considérées comme des régions sensibles.The environmental consequences of road transport with regard to air and noise in the transit valleys of Fréjus, Mont-Blanc, Gotthard, and Brenner have been analysed and compared with each other for the year 2004. In respect of the share of transport passing through the Alps in transport as a whole, there are in part considerable differences between the valleys under investigation as well as within the individual valleys. The air pollution produced per emission unit of road transport is two to three times higher than in the open country, mainly because of the topography and the climate. At numerous monitoring points, the thresholds for the air pollution were exceeded

  5. The Riscos Bayos Ignimbrites of the Caviahue-Copahue volcanic caldera complex, southern Andes, Argentina

    Science.gov (United States)

    Colvin, A.; Merrill, M.; Demoor, M.; Goss, A.; Varekamp, J. C.

    2004-05-01

    The Caviahue-Copahue volcanic complex (38 S, 70 W) is located on the eastern margin of the active arc in the southern Andes, Argentina. Volcán Copahue, an active stratovolcano which hosts an active hydrothermal system, sits on the southwestern rim of the elliptical Caviahue megacaldera (17 x 15 km). The caldera wall sequences are up to 0.6 km thick and consist of lavas with 51 -69 percent SiO2 and 0.2 - 5 percent MgO as well as breccias, dikes, sills, domes and minor ignimbrites. Andesitic lava flows also occur within the caldera, and are overlain by a chaotic complex of silicic lava and intracaldera pyroclastic flow deposits. The eastern wall sequence is capped by several extracaldera ignimbrites (Riscos Bayos formation) of about 50 m maximum thickness which extend 30 km east-southeast of the caldera. Young back-arc alkali basalt scoria cones occur east of the Caviahue-Copahue volcanic complex. The eruption of the Riscos Bayos formation at about 1.1 Ma (12 km cubed) may be related to the Caviahue caldera formation, though the Riscos Bayos account for only about 7 percent of the caldera volume. The Riscos Bayos consists of three lithic-bearing flow units: a grey basal flow, a tan middle flow and a bright-white, highly indurated uppermost flow. The basal unit consists of white and grey pumice fragments, black scoria clasts, black obsidian clasts (which give it the grey color), and accidental volcanic lithics set in a matrix of ash and crystals. The middle unit is composed of large mauve pumice fragments and accidental lithics set in a fine tan ash groundmass. The uppermost unit is composed of small pink and white pumice fragments set in a matrix of fine white ash. These pumices carry quartz and biotite crystals, whereas the lower two units are orthopyroxene-bearing trachy-dacites. The Caviahue-Copahue magmas all bear arc signatures, but possibly some magma mixing between the andesitic arc magmas and basaltic back-arc magmas may have occurred. The evolved top layer

  6. Disponibilidades hídricas para la forestación en el Valle de Calamuchita, Córdoba

    OpenAIRE

    Ravelo, Andrés Carlos; Zanvettor, R. E.; Ingaramo, P.

    1997-01-01

    p.111-116 Las disponibilidades hídricas para la forestación con Pinus elliottii y Pinus taeda en el valle de Calamuchita fueron analizadas utilizando el balance hídrico del suelo. Las similitudes de variables derivadas del balance hidrico para localidades del valle y localidades de origen de ambas especies indica condiciones adecuadas para el desarrollo de dichas especies. Mediante un análisis numérico de agregación se identifican a localidades del lugar de origen como posibles fuentes pro...

  7. The Laramide Mesa formation and the Ojo de Agua caldera, southeast of the Cananea copper mining district, Sonora, Mexico

    Science.gov (United States)

    Cox, Dennis P.; Miller, Robert J.; Woodbourne, Keith L.

    2006-01-01

    The Mesa Formation extends from Cananea, Mexico, southeast to the Sonora River and is the main host rock of Laramide porphyry copper deposits in the Cananea District and at the Alacran porphyry prospect to the east. The Mesa consists of two members-a lower andesite and an upper dacite. The lowest part of the dacite member is a crystal tuff about 100 m thick. This tuff is the outfall of a caldera centered near the village of Ojo de Agua, dated by 40Ar/39Ar at 65.8 Ma ?0.4. The Ojo de Agua Caldera is about 9 km in diameter and is filled by a light gray biotite dacite tuff with abundant flattened pumice fragments. The volume of the caldera is estimated to be 24 km3.

  8. Micromammals (Insectivora; Rodentia of "Valle dell'Inferno" (Rome / Micromammiferi (Insectivora; Rodentia della Valle dell'Inferno (Roma

    Directory of Open Access Journals (Sweden)

    Roberto Federici

    1986-12-01

    Full Text Available Abstract A research on micromammals in the area of "Valle dell'Inferno" (in the north-west of Rome was carried out. The study was based on a previous phytosociological survey which describes a Quercus suber population in the valley (a once larger residua1 of a roman cork-tree wood which is now included in the town. Specimens from Rodents (Apodemus sylvaticus, Mus domesticus, Rattus rattus, R. norvegicus, Pitymys savii and Insectivores (Crocidura suaveolens, Erinaceus europaeus were captured by live traps. Most of Insectivores specimens are represented by C. suaveolens. Generally C. suaveolens lives in sympatry with C. leucodon but no specimens of the latter were found in this area. Three different kinds of landscape are present in the "Inferno" valley, namely, the wood, the meadow, and the bottom valley (with high anthropic impact; we have compared these three landscapes with biotic indexes (index of faunistic affinity, index of biocoenotic affinity and index of environmental evaluation. We have also compared through the same indexes, the micromammal fauna of the "Inferno" valley with six other differently polluted localities in Latium, where animals were captured with the same live traps. This area retains its natura1 environment in despite of the high anthropic impact. Riassunto È stato effettuato uno studio sulla micromammalofauna terrestre della Valle dell'Inferno situata a nord-ovest di Roma. Lo studio è basato su una precedente indagine fitosociologica effettuata per la caratterizzazione vegetazionale di una sughereta un tempo molto estesa ed ora racchiusa nell'abitato cittadino. È stato pertanto possibile tracciare, tramite gli indici biotici, una correlazione tra microteriocenosi ed effetti dell'impatto antropico.

  9. Anomalous shear wave delays and surface wave velocities at Yellowstone Caldera, Wyoming

    International Nuclear Information System (INIS)

    Daniel, R.G.; Boore, D.M.

    1982-01-01

    To investigate the effects of a geothermal area on the propagation of intermediate-period (1--30 s) teleseismic body waves and surface waves, a specially designed portable seismograph system was operated in Yellowstone Caldera, Wyoming. Travel time residuals, relative to a station outside the caldera, of up to 2 s for compressional phases are in agreement with short-period residuals for P phases measured by other investigators. Travel time delays for shear arrivals in the intermediate-period band range from 2 to 9 s and decrease with increasing dT/dΔ. Measured Rayleigh wave phase velocities are extremely low, ranging from 3.2 km/s at 27-s period to 2.0 km/s at 7-s period; the estimated uncertainty associated with these values is 15%. We propose a model for compressional and shear velocities and Poisson's ratio beneath the Yellowstone caldera which fits the teleseismic body and surface wave data: it consists of a highly anomalous crust with an average shear velocity of 3.0 km/s overlying an upper mantle with average velocity of 4.1 km/s. The high average value of Poisson's ratio in the crust (0.34) suggests the presence of fluids there; Poisson's ratio in the mantle between 40 and approximately 200 km is more nearly normal (0.29) than in the crust. A discrepancy between normal values of Poisson's ratio in the crust calculated from short-period data and high values calculated from teleseismic data can be resolved by postulating a viscoelastic crustal model with frequency-dependent shear velocity and attenuation

  10. A fluid-driven earthquake swarm on the margin of the Yellowstone caldera

    Science.gov (United States)

    Shelly, David R.; Hill, David P.; Massin, Frederick; Farrell, Jamie; Smith, Robert B.; Taira, Taka'aki

    2013-01-01

    Over the past several decades, the Yellowstone caldera has experienced frequent earthquake swarms and repeated cycles of uplift and subsidence, reflecting dynamic volcanic and tectonic processes. Here, we examine the detailed spatial-temporal evolution of the 2010 Madison Plateau swarm, which occurred near the northwest boundary of the Yellowstone caldera. To fully explore the evolution of the swarm, we integrated procedures for seismic waveform-based earthquake detection with precise double-difference relative relocation. Using cross-correlation of continuous seismic data and waveform templates constructed from cataloged events, we detected and precisely located 8710 earthquakes during the three-week swarm, nearly four times the number of events included in the standard catalog. This high-resolution analysis reveals distinct migration of earthquake activity over the course of the swarm. The swarm initiated abruptly on January 17, 2010 at about 10 km depth and expanded dramatically outward (both shallower and deeper) over time, primarily along a NNW-striking, ~55º ENE-dipping structure. To explain these characteristics, we hypothesize that the swarm was triggered by the rupture of a zone of confined high-pressure aqueous fluids into a pre-existing crustal fault system, prompting release of accumulated stress. The high-pressure fluid injection may have been accommodated by hybrid shear and dilatational failure, as is commonly observed in exhumed hydrothermally affected fault zones. This process has likely occurred repeatedly in Yellowstone as aqueous fluids exsolved from magma migrate into the brittle crust, and it may be a key element in the observed cycles of caldera uplift and subsidence.

  11. Estudio hidrogeológico del valle de Mala: nivel semidetallado

    OpenAIRE

    Ministerio de Agricultura y Alimentación. Dirección General de Aguas y Suelos; Proyecto Ampliación de la Frontera Agrícola con Utilización de Aguas Subterráneas

    1980-01-01

    Realiza la evaluación del potencial acuífero subterráneo disponible y un estudio considerando aspectos socioeconómicos y agroeconómicos en la zona de la cuenca del valle de Mala (localizada en el departamento de Lima, formando parte de las provincias de Cañete, Huarochirí y Yauyos).

  12. De pescadores y agricultores: una historia local de la gente del valle de Chicama antes de 1565

    Directory of Open Access Journals (Sweden)

    1995-01-01

    Full Text Available DE PECHEURS ET AGRICULTEURS : UNE HISTOIRE LOCALE DES HABITANTS DE LA VALLEE DE CHICAMA AVANT 1565. Une transcription de la deuxième partie d'un manuscrit, daté de 1565 et publié ici, présente l'histoire orale de la vallée de Chicama, racontée par les chefs indigènes de l'époque de Guayna Capac. Une introduction au document donne des informations sur des rencontres entre Européens et indigènes sur l’implantation des Espagnols dans la vallée sur les conceptions différentes de la terre et de la tenure foncière et sur la dégradation du milieu naturel. Se presenta una transcripción de la segunda mitad de un manucristo de 1565 que cuenta la historia oral de los señores étnicos del valle de Chicama desde los tiempos de Guayna Capac. Una introducción al documento pone el manuscrito en su contexto histórico, hablando del encuentro entre los españoles y los naturales del asentamiento español del valle de los conceptos españoles e indígenas acerca de la tierra y la tenencia de dicho valle y la degradación del medio ambiente. ABOUT FISHERMEN AND AGRICULTURISTS: A LOCAL HISTORY OF THE PEOPLE IN CHICAMA'S VALLEY BEFORE 1565. A transcription of the second part of a manuscript, dated 1565 and published here, presents the oral history of the Valley of Chicama, as told by native lords, from the time of Guayna Capac. An introduction to the document provides information on the encounters between Europeans and natives Spanish settlement of the Valley conflicting conceptions of land and tenure and environmental degradation.

  13. Environmental practices of the tourist companies in Valle de Bravo

    International Nuclear Information System (INIS)

    Hernandez Penaloza, Nadia; Zizumbo Villarreal, Lilia; Vargas Martinez, Elva Esther

    2011-01-01

    The present article analyzes the environmental practices of the social actors related to the tourist companies of the municipality of Valle de Bravo, Mexico State. The environmental practices were considered from the socioeconomic point of view, including not only the natural resources management, but also the social and economic environment. Considering the previous, using a methodological proposal based on the theory of complex systems, the effects on the above mentioned environments of this tourist destination were analyzed, allowing to holistically visualizing the situation that prevails towards the environmental caring performed by all the social actors of the locality. The results show a great weakness in the implementation of the above mentioned practices, due to the fact that nowadays these practices are imposed by the municipal government and are not an initiative of the actors of the tourist companies. For this reason, the conditions of environmental deterioration in Valle de Bravo are increasing. Based on the results, some recommendations are proposed for the implementation and improvement of environmental practices that contribute to the conservation and care of the environment.

  14. Seven new species of Loneura Navás (Insecta: Psocodea: 'Psocoptera': Ptiloneuridae) from Valle del Cauca, Colombia.

    Science.gov (United States)

    Nieto, Julián Alexander Mendivil; Aldrete, Alfonso Neri García; Obando, Ranulfo González

    2017-02-06

    Seven species of Loneura from natural areas of Valle del Cauca, Colombia, are described and illustrated. The female of L. andina is described for the first time. Two additional species, known only from the National Natural Park Gorgona (Cauca), are also recorded in Valle del Cauca. The new species are assigned to the infrageneric groups known in the genus. An identification key to males of Loneura is included.

  15. A complex magma reservoir system for a large volume intra- to extra-caldera ignimbrite: Mineralogical and chemical architecture of the VEI8, Permian Ora ignimbrite (Italy)

    Science.gov (United States)

    Willcock, M. A. W.; Bargossi, G. M.; Weinberg, R. F.; Gasparotto, G.; Cas, R. A. F.; Giordano, G.; Marocchi, M.

    2015-11-01

    Intra-caldera settings record a wealth of information on caldera-forming processes, yet field study is rarely possible due to lack of access and exposure. The Permian Ora Formation, Italy, preserves > 1000 m of vertical section through its intra-caldera succession. This provides an excellent opportunity to detail its mineralogical and geochemical architecture and gain understanding of the eruption evolution and insight into the pre-eruptive magma system. Detailed juvenile clast phenocryst and matrix crystal fragment point count and image analysis data, coupled with bulk-rock chemistry and single mineral compositional data, show that the Ora ignimbrite succession is rhyolitic (72.5-77.7% SiO2), crystal-rich (~ 25-57%; average 43%) and has a constant main mineral population (volcanic quartz + sanidine + plagioclase + biotite). Although a seemingly homogeneous ignimbrite succession, important subtle but detectable lateral and vertical variations in modal mineralogy and bulk-rock major and trace elements are identified here. The Ora Formation is comprised of multiple lithofacies, dominated by four densely welded ignimbrite lithofacies. They are crystal-rich, typically lithic-poor (pene-contemporaneous caldera depressions. Moreover, this data illustrates heterogeneity and local zonation from base-to-top of the main intra-caldera and extra-caldera successions. These variations together with crystal fragment size variations between ignimbrite lithofacies support the hypothesis of a multi-vent eruption process, incremental caldera in-filling by subtly compositionally different pyroclastic flow pulses, and a lower intensity eruption style (Willcock et al., 2013, 2014).

  16. Uso de plaguicidas en un valle agrícola tecnificado en el noroeste de México

    OpenAIRE

    LEYVA MORALES, José Belisario; GARCÍA DE LA PARRA, Luz María; BASTIDAS BASTIDAS, Pedro de Jesús; ASTORGA RODRÍGUEZ, Jesús Efrén; BEJARANO TRUJILLO, Jorge; CRUZ HERNÁNDEZ, Alejandro; MARTÍNEZ RODRÍGUEZ, Irma Eugenia; BETANCOURT LOZANO, Miguel

    2014-01-01

    En el presente estudio se comparan dos procedimientos para conocer el uso de plaguicidas durante los ciclos otoño-invierno (O-I) 2011-2012 y primavera-verano (P-V) 2012 en el Valle de Culiacán, Sinaloa. A nivel nacional, este valle es una importante región agrícola tecnificada, productora de hortalizas y granos. Se analizaron las diferencias existentes en cuanto a cantidad total de ingrediente activo, según los registros del programa "Campo Limpio" y bitácoras de aplicación de varias empresas...

  17. Estudio de factibilidad para la creación de un hotel en el Valle del Chota.

    OpenAIRE

    Bautista Espinosa, Carlos

    2008-01-01

    El presente proyecto contiene en el capítulo I, el estudio respecto de la factibilidad de implantar un Hotel & SPA en el Valle del Chota, parroquia Ambuquí, provincia de Imbabura, que brinde el servicio de hospedaje, distracción y relajación. La propuesta busca presentar un servicio turístico de relajación que atienda la demanda de alojamiento tanto interno como receptor que se dirige hacia el Valle del Chota en la parroquia de Ambuquí, adicionalmente se incluye el servicio de SPA con la ...

  18. Gradual caldera collapse at Bárdarbunga volcano, Iceland, regulated by lateral magma outflow.

    Science.gov (United States)

    Gudmundsson, Magnús T; Jónsdóttir, Kristín; Hooper, Andrew; Holohan, Eoghan P; Halldórsson, Sæmundur A; Ófeigsson, Benedikt G; Cesca, Simone; Vogfjörd, Kristín S; Sigmundsson, Freysteinn; Högnadóttir, Thórdís; Einarsson, Páll; Sigmarsson, Olgeir; Jarosch, Alexander H; Jónasson, Kristján; Magnússon, Eyjólfur; Hreinsdóttir, Sigrún; Bagnardi, Marco; Parks, Michelle M; Hjörleifsdóttir, Vala; Pálsson, Finnur; Walter, Thomas R; Schöpfer, Martin P J; Heimann, Sebastian; Reynolds, Hannah I; Dumont, Stéphanie; Bali, Eniko; Gudfinnsson, Gudmundur H; Dahm, Torsten; Roberts, Matthew J; Hensch, Martin; Belart, Joaquín M C; Spaans, Karsten; Jakobsson, Sigurdur; Gudmundsson, Gunnar B; Fridriksdóttir, Hildur M; Drouin, Vincent; Dürig, Tobias; Aðalgeirsdóttir, Guðfinna; Riishuus, Morten S; Pedersen, Gro B M; van Boeckel, Tayo; Oddsson, Björn; Pfeffer, Melissa A; Barsotti, Sara; Bergsson, Baldur; Donovan, Amy; Burton, Mike R; Aiuppa, Alessandro

    2016-07-15

    Large volcanic eruptions on Earth commonly occur with a collapse of the roof of a crustal magma reservoir, forming a caldera. Only a few such collapses occur per century, and the lack of detailed observations has obscured insight into the mechanical interplay between collapse and eruption. We use multiparameter geophysical and geochemical data to show that the 110-square-kilometer and 65-meter-deep collapse of Bárdarbunga caldera in 2014-2015 was initiated through withdrawal of magma, and lateral migration through a 48-kilometers-long dike, from a 12-kilometers deep reservoir. Interaction between the pressure exerted by the subsiding reservoir roof and the physical properties of the subsurface flow path explain the gradual, near-exponential decline of both collapse rate and the intensity of the 180-day-long eruption. Copyright © 2016, American Association for the Advancement of Science.

  19. Title: Long Valley Caldera 2003 through 2012: Overview of low level unrest in the last decade Authors: Stuart Wilkinson, David Hill, Michael Lisowski, Deborah Bergfeld, Margaret Mangan

    Science.gov (United States)

    Wilkinson, S. K.; Hill, D. P.; Lisowski, M.; Bergfeld, D.; Mangan, M.

    2012-12-01

    Long Valley Caldera is located in central California along the eastern escarpment of the Sierra Nevada and at the western edge of the Basin and Range. The caldera formed 0.76 Ma ago during the eruption of 600 cubic kilometers the Bishop Tuff that resulted in the collapse of the partially evacuated magma chamber. Since at least late 1978, Long Valley Caldera has experienced recurring earthquake swarms and ground uplift, suggesting future eruptions are possible. Unrest in Long Valley Caldera during the 1980s to early 2000s is well documented in the literature. Episodes of inflation centered on the resurgent dome in the western part of the caldera occurred in 1979-1980, 1983, 1989-1990, 1997-1998, and 2002-2003, accumulating ~ 80 cm of uplift. Earthquakes of M ≥ 3.0 were numerous in the caldera and in the Sierra Nevada block to the south of the caldera from 1980 through 1983 (800 events including four M~ 6 earthquakes in 1980); in the caldera from 1997 through mid-1998 (150 events); and in the Sierra Nevada block from mid-1998 through 1999 (~160 events) and more modestly from 2002 through 2003 (7 events). In this presentation, we summarize the low-levels of caldera unrest during the last decade. The number of earthquakes in Sierra Nevada block and the caldera has gradually diminished over the last decade. Fifty Sierra Nevada earthquakes had magnitudes 3.0≤M≤4.6. In the caldera, only six earthquakes had magnitudes 3.0≤M≤3.8. A three-month swarm of minor earthquakes (235 events with 0.5≤M≤3.8; most below 2.0) occurred in the caldera in mid-2010. Analysis of continuous GPS data over the last year shows an inflationary pattern within the caldera centered on the resurgent dome, with a maximum uplift rate of ~ 2-3 cm/yr. The rate of deformation is comparable to that of 2002-2003, and well below ~ 70 cm/yr rates observed during the peak of inflation in the late 1990s. Steaming ground and diffuse CO2 discharge has long been a feature of Long Valley Caldera

  20. Evidence for cross rift structural controls on deformation and seismicity at a continental rift caldera

    Science.gov (United States)

    Lloyd, Ryan; Biggs, Juliet; Wilks, Matthew; Nowacki, Andy; Kendall, J.-Michael; Ayele, Atalay; Lewi, Elias; Eysteinsson, Hjálmar

    2018-04-01

    In continental rifts structural heterogeneities, such as pre-existing faults and foliations, are thought to influence shallow crustal processes, particularly the formation of rift faults, magma reservoirs and surface volcanism. We focus on the Corbetti caldera, in the southern central Main Ethiopian Rift. We measure the surface deformation between 22nd June 2007 and 25th March 2009 using ALOS and ENVISAT SAR interferograms and observe a semi-circular pattern of deformation bounded by a sharp linear feature cross-cutting the caldera, coincident with the caldera long axis. The signal reverses in sign but is not seasonal: from June to December 2007 the region south of this structure moves upwards 3 cm relative to the north, while from December 2007 until November 2008 it subsides by 2 cm. Comparison of data taken from two different satellite look directions show that the displacement is primarily vertical. We discuss potential mechanisms and conclude that this deformation is associated with pressure changes within a shallow (statistically consistent with this fault structure, indicating that the fault has also controlled the migration of magma from a reservoir to the surface over tens of thousands of years. Spatial patterns of seismicity are consistent with a cross-rift structure that extents outside the caldera and to a depth of ∼30 km, and patterns of seismic anisotropy suggests stress partitioning occurs across the structure. We discuss the possible nature of this structure, and conclude that it is most likely associated with the Goba-Bonga lineament, which cross-cuts and pre-dates the current rift. Our observations show that pre-rift structures play an important role in magma transport and shallow hydrothermal processes, and therefore they should not be neglected when discussing these processes.

  1. Three-Dimensional P-wave Velocity Structure Beneath Long Valley Caldera, California, Using Local-Regional Double-Difference Tomography

    Science.gov (United States)

    Menendez, H. M.; Thurber, C. H.

    2011-12-01

    Eastern California's Long Valley Caldera (LVC) and the Mono-Inyo Crater volcanic systems have been active for the past ~3.6 million years. Long Valley is known to produce very large silicic eruptions, the last of which resulted in the formation of a 17 km by 32 km wide, east-west trending caldera. Relatively recent unrest began between 1978-1980 with five ML ≥ 5.7 non-double-couple (NDC) earthquakes and associated aftershock swarms. Similar shallow seismic swarms have continued south of the resurgent dome and beneath Mammoth Mountain, surrounding sites of increased CO2 gas emissions. Nearly two decades of increased volcanic activity led to the 1997 installation of a temporary three-component array of 69 seismometers. This network, deployed by the Durham University, the USGS, and Duke University, recorded over 4,000 high-frequency events from May to September. A local tomographic inversion of 283 events surrounding Mammoth Mountain yielded a velocity structure with low Vp and Vp/Vs anomalies at 2-3 km bsl beneath the resurgent dome and Casa Diablo hot springs. These anomalies were interpreted to be CO2 reservoirs (Foulger et al., 2003). Several teleseismic and regional tomography studies have also imaged low Vp anomalies beneath the caldera at ~5-15 km depth, interpreted to be the underlying magma reservoir (Dawson et al., 1990; Weiland et al., 1995; Thurber et al., 2009). This study aims to improve the resolution of the LVC regional velocity model by performing tomographic inversions using the local events from 1997 in conjunction with regional events recorded by the Northern California Seismic Network (NCSN) between 1980 and 2010 and available refraction data. Initial tomographic inversions reveal a low velocity zone at ~2 to 6 km depth beneath the caldera. This structure may simply represent the caldera fill. Further iterations and the incorporation of teleseismic data may better resolve the overall shape and size of the underlying magma reservoir.

  2. Perception of the general population in Ciudad Valles, San Luis Potosi regarding waste production in hairdressing salons

    Directory of Open Access Journals (Sweden)

    Juan José Maldonado-Miranda

    2016-02-01

    Full Text Available Hairdressing salons offer a wide range of services including treatments for hair and skin. However, these activities result in the production of residues that are improperly discharged into drainage, generating a negative impact on the environment. This study provides results of a first stage in a project regarding the analysis of waste disposal in hairdressing salons in the municipality of Ciudad Valles, San Luis Potosi, Mexico. Information gathering was conducted through a field work study by surveys given to workers in hairdressing salons in Ciudad Valles. The information presented in this study indicates that in hairdressing salons in Ciudad Valles there is no management plan for the management of waste that could be severely impacting the environment. The information presented here will be the basis for identifying priority areas for intervention, developing new research projects and setting new environmental policies. In addition, the results presented here can be extrapolated to many rural and urban areas all over Mexico.

  3. Pucarilla-Cerro Tipillas volcanic complex: the oldest recognized caldera in the southeastern portion of central volcanic zone of Central Andes?

    Energy Technology Data Exchange (ETDEWEB)

    Guzman, Silvina; Petrinovic, Ivan [CONICET -IBIGEO. Museo de Cs. Naturales, Universidad de Salta, Mendoza 2 (4400), Salta (Argentina)], E-mail: guzmansilvina@gmail.com

    2008-10-01

    We recognize the most eastern and oldest collapse caldera structure in the southern portion of the Central Volcanic Zone of the Andes. A description of Middle-Upper Miocene successions related to explosive- effusive events is presented. The location of this centre close to Cerro Galn Caldera attests a recurrence in the volcanism between 12 and 2 Ma in this portion of the Altiplano - Puna Plateau.

  4. Evidence from cosmic ray exposure (CRE) dating for the existence of a pre-Minoan caldera on Santorini, Greece

    Science.gov (United States)

    Athanassas, C. D.; Bourlès, D. L.; Braucher, R.; Druitt, T. H.; Nomikou, P.; Léanni, L.

    2016-05-01

    Cosmic ray exposure (CRE) dating was performed on the caldera cliffs of Santorini with the aim of detecting cliff segments predating the Minoan eruption (17th century BCE). The methodology involved the determination of in situ-produced cosmogenic 36Cl concentration in basaltic-to-rhyodacitic whole rocks cropping out in the cliffs. After the samples were processed following the chemical protocol of 36Cl preparation for silicate rocks, 36Cl concentrations were measured by accelerator mass spectrometry (AMS). Important challenges during the implementation procedure were related to large amounts of radiogenic 36Cl, complex modeling of inherited 36Cl, and dominance of the thermal and epithermal (low-energy) neutron capture production pathway. Nevertheless, quantitative assessments on the basis of the contribution of the low-energy neutron capture pathway percent to the total production rate validated the calculated CRE dates. Current CRE ages demonstrate that an ancient caldera existed on pre-Minoan Santorini, occupying at least the northern half of the modern-day caldera.

  5. Nuevos datos sobre la Huaca China, valle del Santa, Perú

    Directory of Open Access Journals (Sweden)

    2004-01-01

    Full Text Available La présence Moche dans la vallée du Santa s’appuie sur l’existence de nombreux sites dont certains sont considérés comme des centres locaux importants. Huaca China est l’un de ces sites stratégiques dans la partie sud-ouest de la vallée. Des récoltes de surface combinées avec le nettoyage de six trous de pilleurs permettent l’identification d’une présence Moche et d’une forte occupation datant de l’Horizon Moyen. En plus de présenter une tombe de la culture Tanguche, les principales découvertes sont décrites dans l’optique de vérifier la présence Moche, son importance et la possibilité que les Moche aient construit les murailles entourant une petite plate-forme érigée sur le sommet de la colline. La presencia Moche en el valle del Santa se apoya en la existencia de numerosos sitios entre los cuales varios son considerados centros locales de importancia. Huaca China es uno de estos sitios estratégicos en la parte suroeste del valle. Las recolecciones de superficie y la limpieza de pozos de huaquero permiten la identificación de una presencia Moche y de una fuerte ocupación durante el Horizonte Medio. Además de presentar una sepultura de la cultura Tanguche, se describen los principales hallazgos con la finalidad de verificar la presencia Moche, su importancia, y se discute la posibilidad de que los Moche hayan construido las murallas que rodean una pequeña plataforma erigida en la cima de la colina donde se ubica este sitio. A Moche presence in the Santa Valley is supported by numerous sites, and the local centers have been identified. Huaca China in the south western portion of the valley is one of them. Surface collections combined with the cleaning of six looter’s pit allowed the identification of a Moche presence and also a strong Middle Horizon component. A Tanguche culture tomb is described and followed by the presentation of major cultural elements in order to establish the Moche presence, its importance, and

  6. Summary of recent research in Long Valley Caldera, California

    Science.gov (United States)

    Sorey, M.L.; McConnell, V.S.; Roeloffs, E.

    2003-01-01

    Since 1978, volcanic unrest in the form of earthquakes and ground deformation has persisted in the Long Valley caldera and adjacent parts of the Sierra Nevada. The papers in this special volume focus on periods of accelerated seismicity and deformation in 1980, 1983, 1989-1990, and 1997-1998 to delineate relations between geologic, tectonic, and hydrologic processes. The results distinguish between earthquake sequences that result from relaxation of existing stress accumulation through brittle failure and those in which brittle failure is driven by active intrusion. They also indicate that in addition to a relatively shallow (7-10-km) source beneath the resurgent dome, there exists a deeper (???15-km) source beneath the south moat. Analysis of microgravimety and deformation data indicates that the composition of the shallower source may involve a combination of silicic magma and hydrothermal fluid. Pressure and temperature fluctuations in wells have accompanied periods of crustal unrest, and additional pressure and temperature changes accompanying ongoing geothermal power production have resulted in land subsidence. The completion in 1998 of a 3000-m-deep drill hole on the resurgent dome has provided useful information on present and past periods of circulation of water at temperatures of 100-200??C within the crystalline basement rocks that underlie the post-caldera volcanics. The well is now being converted to a permanent geophysical monitoring station. ?? 2003 Elsevier B.V. All rights reserved.

  7. El polen de las mieles del valle de Río Negro, provincia fitogeográfica del monte (Argentina

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    María C. Tellería

    2000-01-01

    Full Text Available Tellería, M. C. & Forcone, A. 2000. El polen de las mieles del valle de Río Negro, provinciafitogeográfica del monte (Argentina. Darwiniana 38(3-4: 273-277.Se realizó el análisis palinológico de 41 muestras de miel del valle de Río Negro. El contenido polínicode las muestras fue acetolizado e identificado por comparación con una colección de polen de referencia.Del total de muestras examinadas, 26 fueron mixtas y las restantes monoflorales de: Tamarix gallica (8muestras, Eucalyptus sp. (2 muestras, Melilotus sp. (1 muestra, Centaurea sp. (1 muestra, Prosopissp. (1 muestra, Brassicaceae (1 muestra y Monttea aphylla (1 muestra. Estas mieles pueden diferenciar-se de aquellas que se producen en el valle inferior del río Chubut, en la misma región fitogeográfica

  8. Rhyolitic calderas and centers clustered within the active andesitic belt of Ecuador's Eastern Cordillera

    Energy Technology Data Exchange (ETDEWEB)

    Mothes, Patricia A; Hall, Minard L [Instituto Geofisico, Escuela Politecnica Nacional, Quito (Ecuador)], E-mail: pmothes@igepn.edu.ec

    2008-10-01

    In the Ecuadorian volcanic arc a cluster of scattered rhyolitic and dacitic centers within the mainly andesitic Eastern Cordillera includes large caldera structures (Chalupas, Chacana, Cosanga) as well as smaller edifices, built upon the Paleozoic-Mesozoic metamorphic basement. At the Chacana caldera magmatism dates from 2.7 Ma to historic times. These centers erupted enormous ash flows and thick pumice lapilli falls that covered the InterAndean Valley near Quito. The role of the 50-70 km-thick crust with a notable negative gravity anomaly appears to be related to the generation of this highly silicic magmatism occurring along the crest of the Andes in the NVZ.

  9. Formación del patrimonio gastronómico del Valle de Toluca, México

    Directory of Open Access Journals (Sweden)

    Alejandro Tonatiuh Romero Contreras

    2011-01-01

    Full Text Available Se describe la formación de la cocina patrimonial de la región de Toluca como primer paso para su investigación culinaria. Se utilizó información etnohistórica de primera mano (cronistas y la consulta de libros, recetarios, tesis y otros documentos, relacionándolos con las características ambientales y culturales del Valle de Toluca. Se identificaron las especies animales y vegetales, así como las prácticas agrícolas-culinarias que trajeron consigo los españoles y su fusión con sus similares locales, lo que produjo el mestizaje gastronómico en el Valle de Toluca expresado en sus platillos patrimoniales: barbacoas, embutidos, moles, tamales, dulces y bebidas tradicionales.

  10. Effects of host rock stratigraphy on the formation of ring-faults and the initiation of collapse calderas

    International Nuclear Information System (INIS)

    Kinvig, H S; Geyer, A; Gottsmann, J

    2008-01-01

    Most collapse calderas can be attributed to subsidence of the magma chamber roof along bounding sub-vertical normal faults (ring-faults) after a decompression of the magma chamber, following eruption. Here, we present new numerical models that use a Finite Element Method to investigate the effects of variable crustal stratigraphy (lithology/thickness/order of strata) above a magma chamber, on local stress field distribution and how these in turn compare with existing criteria for ring-fault initiation. Results indicate that the occurrence and relative distribution of mechanically different lithologies may be influential in generating or inhibiting caldera collapse.

  11. Effects of host rock stratigraphy on the formation of ring-faults and the initiation of collapse calderas

    Energy Technology Data Exchange (ETDEWEB)

    Kinvig, H S; Geyer, A; Gottsmann, J [Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queen' s Road, BS8 1RJ, Bristol (United Kingdom)

    2008-10-01

    Most collapse calderas can be attributed to subsidence of the magma chamber roof along bounding sub-vertical normal faults (ring-faults) after a decompression of the magma chamber, following eruption. Here, we present new numerical models that use a Finite Element Method to investigate the effects of variable crustal stratigraphy (lithology/thickness/order of strata) above a magma chamber, on local stress field distribution and how these in turn compare with existing criteria for ring-fault initiation. Results indicate that the occurrence and relative distribution of mechanically different lithologies may be influential in generating or inhibiting caldera collapse.

  12. El Morro caldera (33° 10‧ S, 66° 24‧ W), San Luis, Argentina: An exceptional case of fossil pre-collapse updoming

    Science.gov (United States)

    Sruoga, P.; Ibañes, O. D.; Japas, M. S.; Urbina, N. E.

    2017-05-01

    Volcanism at Sierra del Morro represents the final stages of the flat-slab related magmatism in the easternmost San Luis Neogene Volcanic Belt. This 80 km-long NW-WNW-trending belt tracks the episodic inland migration of both magmatism and tectonic deformation since 18 Ma. The Sierra del Morro stands out in the Eastern Sierras Pampeanas as a metamorphic block uplifted during the Late Miocene-Pleistocene by a combination of magma injection and tectonic deformation. Although sequences that preserve stages of basement updoming are not often preserved, exposures in Sierra del Morro are exception in providing key evidence and insight into the involved processes. Based on the comprehensive study of volcanic stratigraphy and structures, the reconstruction of the volcanic architecture has been carried out. We infer a three stage evolution of the El Morro caldera as follows: 1) pre-collapse updoming and volcanism, 2) collapse caldera formation and 3) post-caldera volcanism. The ascent of magma is recorded in small tumescence sites, strongly controlled by oblique transtensional WNW-NW and ENE-striking brittle-ductile megashear zones. Even though the area affected by tumescence was large, magma injection progressed only locally. At Cerros Guanaco and Pampa, metamorphic rocks were updomed and strongly brecciated, whereas at Sierra del Morro magma was emplaced as pre-collapse domes with associated block-and-ash flows, ignimbrite caldera-forming eruptions and post-caldera lava domes and dykes. The caldera is located in the intersection of two major oblique transtensional WNW-NW and ENE-trending brittle-ductile megashear zones, where the highest positive dilatation occurred.

  13. Kapital ja sotsiaalsed vajadused / Robin Blackburn ; ref. Valle-Sten Maiste

    Index Scriptorium Estoniae

    Blackburn, Robin

    2006-01-01

    Autori väitel püüdleb EL vaid siseturu laiendamise poole, pakkumata sotsiaalset turvalisust ja maksude ühtlustamist. Euroopa vajab märgatavalt efektiivsemaid korporatsioonide maksustamise viise, millele järgneks sotsiaalsete fondide võrgustiku rajamine. Sotsiaalsete fondide kaudu ei jaotataks ainult rikkust ümber, vaid investeeritaks ka loodus- ja tööskeskkonda. Vt. samas ka Valle-Sten Maiste art. "Naabrist rohkem pappi"

  14. Tilted lake shorelines record the onset of motion along the Hilton Creek fault adjacent to Long Valley caldera, CA, USA

    Science.gov (United States)

    Perkins, J. P.; Finnegan, N. J.; Cervelli, P. F.; Langbein, J. O.

    2010-12-01

    Prominent normal faults occur within and around Long Valley caldera, in the eastern Sierra Nevada of California. However, their relationship to both the magmatic and tectonic evolution of the caldera since the 760 ka eruption of the Bishop Tuff remains poorly understood. In particular, in the Mono-Inyo Craters north of Long Valley, extensional faulting appears to be replaced by dike intrusion where magma is available in the crust. However, it is unclear whether extensional faults in Long Valley caldera have been active since the eruption of the Bishop Tuff (when the current topography was established) or are a relatively young phenomenon owing to the cooling and crystallization of the Long Valley magma reservoir. Here we use GPS geodesy and geomorphology to investigate the evolution of the Hilton Creek fault, the primary range-front fault bounding Long Valley caldera to the southwest. Our primary goals are to determine how long the Hilton Creek fault has been active and whether slip rates have been constant over that time interval. To characterize the modern deformation field, we capitalize on recently (July, 2010) reoccupied GPS benchmarks first established in 1999-2000. These fixed-array GPS data show no discernible evidence for recent slip on the Hilton Creek fault, which further highlights the need for longer-term constraints on fault motion. To establish a fault slip history, we rely on a suite of five prominent shorelines from Pleistocene Long Valley Lake whose ages are well constrained based on field relationships to dated lavas, and that are tilted southward toward the Hilton Creek fault. A preliminary analysis of shoreline orientations using GPS surveys and a 5-m-resolution Topographic Synthetic Aperture Radar (TOPSAR) digital elevation model shows that lake shorelines tilt towards the Hilton Creek fault at roughly parallel gradients (~ 0.6%). The measured shorelines range in inferred age from 100 ka to 500 ka, which constrain recent slip on the Hilton

  15. Layered hydrothermal barite-sulfide mound field, East Diamante Caldera, Mariana volcanic arc

    Science.gov (United States)

    Hein, James R.; de Ronde, Cornel E. J.; Koski, Randolph A.; Ditchburn, Robert G.; Mizell, Kira; Tamura, Yoshihiko; Stern, Robert J.; Conrad, Tracey; Ishizuka, Osamu; Leybourne, Matthew I.

    2014-01-01

    East Diamante is a submarine volcano in the southern Mariana arc that is host to a complex caldera ~5 × 10 km (elongated ENE-WSW) that is breached along its northern and southwestern sectors. A large field of barite-sulfide mounds was discovered in June 2009 and revisited in July 2010 with the R/V Natsushima, using the ROV Hyper-Dolphin. The mound field occurs on the northeast flank of a cluster of resurgent dacite domes in the central caldera, near an active black smoker vent field. A 40Ar/39Ar age of 20,000 ± 4000 years was obtained from a dacite sample. The mound field is aligned along a series of fractures and extends for more than 180 m east-west and >120 m north-south. Individual mounds are typically 1 to 3 m tall and 0.5 to 2 m wide, with lengths from about 3 to 8 m. The mounds are dominated by barite + sphalerite layers with the margins of each layer composed of barite with disseminated sulfides. Rare, inactive spires and chimneys sit atop some mounds and also occur as clusters away from the mounds. Iron and Mn oxides are currently forming small (caldera, mineralization resulted from focused flow along small segments of linear fractures rather than from a point source, typical of hydrothermal chimney fields. Based on the mineral assemblage, the maximum fluid temperatures were ~260°C, near the boiling point for the water depths of the mound field (367–406 m). Lateral fluid flow within the mounds precipitated interstitial sphalerite, silica, and Pb minerals within a network of barite with disseminated sulfides; silica was the final phase to precipitate. The current low-temperature precipitation of Fe and Mn oxides and silica may represent rejuvenation of the system.

  16. Stratigraphy and mineralogy of Candor Mensa, West Candor Chasma, Mars: Insights into the geologic history of Valles Marineris

    Science.gov (United States)

    Fueten, F.; Flahaut, J.; Stesky, R.; Hauber, E.; Rossi, A. P.

    2014-02-01

    Candor Mensa, an interior layered deposit (ILD) in Valles Marineris, Mars, consists of two stratigraphically distinct units, the lower of which comprises the bulk of the mensa. This lower unit is approximately 5 km thick and composed of parallel layers, 4 to 14 m in thickness and associated with monohydrated sulfates. The lower unit is disconformably overlain by an upper unit composed of thinner (ancestral basins into the current geometry of Valles Marineris chasmata and that it was possible to form hydrated minerals after this event.

  17. Thermomechanical controls on magma supply and volcanic deformation: application to Aira caldera, Japan

    Science.gov (United States)

    Hickey, James; Gottsmann, Joachim; Nakamichi, Haruhisa; Iguchi, Masato

    2016-01-01

    Ground deformation often precedes volcanic eruptions, and results from complex interactions between source processes and the thermomechanical behaviour of surrounding rocks. Previous models aiming to constrain source processes were unable to include realistic mechanical and thermal rock properties, and the role of thermomechanical heterogeneity in magma accumulation was unclear. Here we show how spatio-temporal deformation and magma reservoir evolution are fundamentally controlled by three-dimensional thermomechanical heterogeneity. Using the example of continued inflation at Aira caldera, Japan, we demonstrate that magma is accumulating faster than it can be erupted, and the current uplift is approaching the level inferred prior to the violent 1914 Plinian eruption. Magma storage conditions coincide with estimates for the caldera-forming reservoir ~29,000 years ago, and the inferred magma supply rate indicates a ~130-year timeframe to amass enough magma to feed a future 1914-sized eruption. These new inferences are important for eruption forecasting and risk mitigation, and have significant implications for the interpretations of volcanic deformation worldwide. PMID:27619897

  18. Thermomechanical controls on magma supply and volcanic deformation: application to Aira caldera, Japan.

    Science.gov (United States)

    Hickey, James; Gottsmann, Joachim; Nakamichi, Haruhisa; Iguchi, Masato

    2016-09-13

    Ground deformation often precedes volcanic eruptions, and results from complex interactions between source processes and the thermomechanical behaviour of surrounding rocks. Previous models aiming to constrain source processes were unable to include realistic mechanical and thermal rock properties, and the role of thermomechanical heterogeneity in magma accumulation was unclear. Here we show how spatio-temporal deformation and magma reservoir evolution are fundamentally controlled by three-dimensional thermomechanical heterogeneity. Using the example of continued inflation at Aira caldera, Japan, we demonstrate that magma is accumulating faster than it can be erupted, and the current uplift is approaching the level inferred prior to the violent 1914 Plinian eruption. Magma storage conditions coincide with estimates for the caldera-forming reservoir ~29,000 years ago, and the inferred magma supply rate indicates a ~130-year timeframe to amass enough magma to feed a future 1914-sized eruption. These new inferences are important for eruption forecasting and risk mitigation, and have significant implications for the interpretations of volcanic deformation worldwide.

  19. The Late Cretaceous Middle Fork caldera, its resurgent intrusion, and enduring landscape stability in east-central Alaska

    Science.gov (United States)

    Bacon, Charles R.; Dusel-Bacon, Cynthia; Aleinikoff, John N.; Slack, John F.

    2014-01-01

    Dissected caldera structures expose thick intracaldera tuff and, uncommonly, cogenetic shallow plutons, while remnants of correlative outflow tuffs deposited on the pre-eruption ground surface record elements of ancient landscapes. The Middle Fork caldera encompasses a 10 km × 20 km area of rhyolite welded tuff and granite porphyry in east-central Alaska, ∼100 km west of the Yukon border. Intracaldera tuff is at least 850 m thick. The K-feldspar megacrystic granite porphyry is exposed over much of a 7 km × 12 km area having 650 m of relief within the western part of the caldera fill. Sensitive high-resolution ion microprobe with reverse geometry (SHRIMP-RG) analyses of zircon from intracaldera tuff, granite porphyry, and outflow tuff yield U-Pb ages of 70.0 ± 1.2, 69.7 ± 1.2, and 71.1 ± 0.5 Ma (95% confidence), respectively. An aeromagnetic survey indicates that the tuff is reversely magnetized, and, therefore, that the caldera-forming eruption occurred in the C31r geomagnetic polarity chron. The tuff and porphyry have arc geochemical signatures and a limited range in SiO2 of 69 to 72 wt%. Although their phenocrysts differ in size and abundance, similar quartz + K-feldspar + plagioclase + biotite mineralogy, whole-rock geochemistry, and analytically indistinguishable ages indicate that the tuff and porphyry were comagmatic. Resorption of phenocrysts in tuff and porphyry suggests that these magmas formed by thermal rejuvenation of near-solidus or solidified crystal mush. A rare magmatic enclave (54% SiO2, arc geochemical signature) in the porphyry may be similar to parental magma and provides evidence of mafic magma and thermal input.

  20. POLÍTICA PÚBLICA AMBIENTAL Y AMBIENTE EN EL VALLE DEL CAUCA, 1991-2010

    Directory of Open Access Journals (Sweden)

    Álvaro Quiceno Martínez

    2010-01-01

    Full Text Available La política pública ambiental en el Valle del Cauca, a partir de 1991, va en contravía de la conservación ambiental al enfatizar en el crecimiento económico, la generación de plusvalía y la ampliación de la tasa de ganancia. Para la realización de esta investigación se adoptó como herramienta metodológica la revisión bibliográfica. Se halló que la política pública ambiental en el Valle se ha orientado a subsidiar monetaria, ecológica, ambiental y socialmente al sector cañicultor. Se concluye que dicha política ha contribuido al desequilibrio ecológico y al deterioro ambiental.

  1. Ignimbrite Analyses of Batur Caldera, Bali, based on 14C Dating

    Directory of Open Access Journals (Sweden)

    Igan S. Sutawidjaja

    2014-06-01

    Full Text Available http://dx.doi.org/10.17014/ijog.vol4no3.20094The Batur Caldera, in the northeastern part of Bali Island, is an elliptical collapse structure 13.8 by 10 km in size and another circular composite collapse structure with a diameter of 7.5 km in its centre. Two stages of the collapse were interrupted by silicic andesite lavas and domes. The first collapse was initiated by the eruption of about 84 km3 of the dacitic "Ubud Ignimbrite", about 29,300 years B.P., which caused a steep-walled depression about 1 km deep. The second ignimbrite was erupted from a large crater about the present lake, and it  produced about 19 km3 of a similar voluminous dacitic ignimbrite, called the "Gunungkawi Ignimbrite" about 20,150 years B.P. This second eruption trig- gered a second collapse, which created the central circular caldera, and formed a basin structure. Both the Ubud and Gunungkawi Ignimbrites consist of a similar dacitic composition, white to red (the most abundant nearly 90 % and dark grey to black dacitic pumice clasts. The large clasts, up to 20 cm in diameter, are in the non-welded ignimbrite, particularly in the upper part of the Gunungkawi Ignimbrite. The intracaldera ignimbrite, called the "Batur Ignimbrite" about 5 km3  in volume is a densely welded ignimbrite and generally shows typical welded features. The ignimbrite comprises at least five different flow units, separated by thin (15 - 40 cm welded pumiceous airfall deposits, with flattened pumice clasts. Another large eruption occurred about 5,500 years B.P., producing around 0.09 km3  andesitic ignimbrite. This was initiated by phreatomagmatic eruptions, indicated by thick phreatomagmatic and surge deposits, underlying the ignimbrite. The caldera and its vicinity are partly filled, and variably mantled by later eruptive products of dacitic and andesitic phreatomagmatic and airfall deposits.  

  2. Geochemical constraints on the link between volcanism and plutonism at the Yunshan caldera complex, SE China

    Science.gov (United States)

    Yan, Lili; He, Zhenyu; Beier, Christoph; Klemd, Reiner

    2018-01-01

    The Yunshan caldera complex is part of a larger scale, ca. 2000-km-long volcanic-plutonic complex belt in the coastal region of SE China. The volcanic rocks in the caldera complex are characterized by high-silica peraluminous and peralkaline rhyolites associated with an intracaldera porphyritic quartz monzonite pluton. In this study, we present zircon U-Pb, Hf and stable O isotopes along with geochemical data of both volcanic and plutonic rocks to evaluate the potential petrogenetic link between volcanism and plutonism in the Yunshan caldera complex. SHRIMP zircon U-Pb geochronology of both volcanic and plutonic rocks yields almost identical ages ranging from 95.6 to 93.1 Ma. The peraluminous and peralkaline rhyolites show negative anomalies of Sr, P, Ti and Ba and to a lesser extent negative Nb and Ta anomalies, along with positive Rb anomalies and `seagull-like' rare earth element (REE) patterns with negative Eu anomalies and low (La/Yb)N ratios. The intracaldera porphyritic quartz monzonite displays minor negative Rb, Nb, Ta, Sr, P and Ti anomalies and a positive Ba anomaly with REE patterns characterized by relatively high (La/Yb)N ratios and lack significant Eu anomalies. The peraluminous and peralkaline rhyolites and the porphyritic quartz monzonite exhibit consistent ɛ Nd( t) of - 3.7 to - 2.2 and display zircon ɛ Hf( t) values of - 2.1 to 3.7. They further have similar, mantle-like, zircon oxygen isotopic compositions (δ18OVSMOW mainly = 4.63 to 5.76‰). We interpret these observations to be in agreement with a crystal mush model in which the parental magma of the volcanic and plutonic rocks of the Yunshan caldera complex was likely produced by interaction of asthenosphere melts with subduction-influenced enriched mantle wedge. The peralkaline rhyolites are interpreted to represent the most differentiated magma that has subsequently experienced significant fluid-melt interactions, whereas the porphyritic quartz monzonite may be representative of the

  3. Observación Electoral: Experiencia de la MOE Regional Valle del Cauca, Elecciones Nacionales de Colombia 2010

    OpenAIRE

    Escobar Higuera, Katherine

    2013-01-01

    En el presente artículo se reseña la experiencia de Observación electoral en el departamento del Valle del Cauca, por parte de la Misión de Observación Electoral MOE regional Valle. Con el propósito de visibilizar el trabajo de una red de organizaciones y personas que han tomado iniciativa en el mejoramiento de un proceso importante para el sistema democrático colombiano, las elecciones. Al reseñar esta experiencia, se espera sea referente de una acción de participación política desde las org...

  4. Genomic characterisation of Arachis porphyrocalyx (Valls & C.E. Simpson, 2005) (Leguminosae): multiple origin of Arachis species with x = 9

    Science.gov (United States)

    Celeste, Silvestri María; Ortiz, Alejandra Marcela; Robledo, Germán Ariel; Valls, José Francisco Montenegro; Lavia, Graciela Inés

    2017-01-01

    Abstract The genus Arachis Linnaeus, 1753 comprises four species with x = 9, three belong to the section Arachis: Arachis praecox (Krapov. W.C. Greg. & Valls, 1994), Arachis palustris (Krapov. W.C. Greg. & Valls, 1994) and Arachis decora (Krapov. W.C. Greg. & Valls, 1994) and only one belongs to the section Erectoides: Arachis porphyrocalyx (Valls & C.E. Simpson, 2005). Recently, the x = 9 species of section Arachis have been assigned to G genome, the latest described so far. The genomic relationship of Arachis porphyrocalyx with these species is controversial. In the present work, we carried out a karyotypic characterisation of Arachis porphyrocalyx to evaluate its genomic structure and analyse the origin of all x = 9 Arachis species. Arachis porphyrocalyx showed a karyotype formula of 14m+4st, one pair of A chromosomes, satellited chromosomes type 8, one pair of 45S rDNA sites in the SAT chromosomes, one pair of 5S rDNA sites and pericentromeric C-DAPI+ bands in all chromosomes. Karyotype structure indicates that Arachis porphyrocalyx does not share the same genome type with the other three x = 9 species and neither with the remaining Erectoides species. Taking into account the geographic distribution, morphological and cytogenetic features, the origin of species with x = 9 of the genus Arachis cannot be unique; instead, they originated at least twice in the evolutionary history of the genus. PMID:28919947

  5. Calidad de aguas naturales y residuales en el sistema hidrográfico Valle del Mezquital, Hidalgo México.

    OpenAIRE

    Barrios Castillo, Isaac Mateo

    2014-01-01

    Actualmente se ha usado prácticamente toda el agua disponible para satisfacer los requerimientos de los diferentes cultivos que se explotan en la agricultura bajo riego. Cada vez más se utilizan hasta el límite las aguas superficiales y subterráneas de la más variada composición química y concentración de sales. En México, se riegan aproximadamente 180,000 ha en diferentes lugares del Valle del Mezquital con aguas residuales urbano-industriales que derivan de la zona metropolitana del Valle d...

  6. DIAGNÓSTICO Y PROPUESTA PARA UNA GESTIÓN INTEGRAL DEL RIESGO EN EL VALLE DE ABURRA: RED RIESGOS

    OpenAIRE

    ARISTIZÁBAL EDIER; VARGAS RICHARD

    2010-01-01

    A partir del análisis de la situación organizacional de las diferentes instituciones en el Valle de Aburrá frente a la reducción de desastres y emergencias asociadas con los fenómenos de origen natural y antrópico, el Área Metropolitana del Valle de Aburrá, como autoridad ambiental y entidad planificadora, hace una propuesta que pretende articular todas las entidades, organizaciones e instituciones públicas y privadas hacia una gestión integral del riesgo, y la cual denominó: Red para la Gest...

  7. Galileo's Last Fly-Bys of Io: NIMS Observations of Loki, Tupan, and Emakong Calderas

    Science.gov (United States)

    Lopes, Rosaly M. C.; Kamp, L. W.; Davies, A. G.; Smythe, W. D.; Carlson, R. W.; Doute, S.; McEwen, A.; Turtle, E. P.; Leader, F.; Mehlman, R.

    2002-01-01

    NIMS results from the 2001 Galileo fly-bys of Io will be presented, focusing on three calderas that may contain lava lakes. Preliminary results from the January 2002 Io fly-by will be presented. Additional information is contained in the original extended abstract.

  8. Sistema de detección de fallos basado en PC en calderas pirotubulares

    OpenAIRE

    Rivas Pérez, R.; Feliu Batlle, V.; Sotomayor Moriano, J.

    2005-01-01

    Se ofrece un sistema basado en PC para la detección de fallos en calderas pirotubulares. Se presentan los algoritmos que posibilitan la detección rápida de fallos abruptos en esta clase de plantas, los cuales se basan en la detección de cambios en los

  9. Proyecto MeCIN: Alto Valle de Río Negro, Argentina MeCIN Project: alto Valle of Rio negro, Argentina

    Directory of Open Access Journals (Sweden)

    Alberto L Flores

    2006-12-01

    Full Text Available Este trabajo presenta los resultados obtenidos durante el experimento de campo MeCIN (Mediciones de la Capa de Inversión Nocturna cuyo objetivo fue estudiar el comportamiento del viento, la temperatura del aire y la evolución del enfriamiento en los valles de los ríos Neuquén, Limay y Negro en noches con inversión térmica en las primaveras de los años 1992 al 1997. Las situaciones sinópticas que propiciaron los intensos efectos radiativos nocturnos fueron asociadas con un anticiclón migratorio postfrontal en 1000 hPa y un eje de vaguada en 500 hPa. Los gradientes verticales de temperatura alcanzaron valores medios entre 0,26 °C/m en el valle del río Neuquén y 0,14 °C/m en el del Negro. El tope de la inversión térmica, en promedio, se ubicó a más de 30 m. Las mediciones de los perfiles de velocidad del viento mostraron un patrón de dos capas: una capa inferior sin movimiento y otra superior con velocidades en promedio entre 2,9 m/s y 4,0 m/s. El enfriamiento nocturno fue superior en la zona de chacras y menor en cercanías del río y sobre la meseta. La temperatura del aire durante la noche fue menor en el valle que en la meseta, dependiendo de su altura.This paper presents the results of field experience MeCIN (Measurements of the Nocturnal Inversion Layer. The project was performed to study the characteristics of wind, air temperature and the evolution of nocturnal cooling in the Neuquén, Limay, and Negro river valleys during nighttime with thermal inversion in the layer near ground, between 1992 and 1997 spring seasons. The mean synoptic situations that favored the nocturnal radiative effects were associated with migratory postfrontal 1000 hPa anticyclones and a though axis in 500 hPa. The mean vertical gradient of air temperature was 0,26 °C/m in the Neuquén river valley and 0,14 °C/m in the Negro river valley. The top of the thermal inversion, on the average, was located above 30 m. The wind speed profile presented two

  10. An updated biostratigraphy for the late Aragonian and Vallesian of the Valles Basin (Catalonia)

    Energy Technology Data Exchange (ETDEWEB)

    Casanovas-Vilar, I.; Garces, M.; Dam, J. van; Garcia-Paredes, I.; Robles, J.M.; Alba, D.M.

    2016-07-01

    The Valles Basin (Catalonia, Spain) is a classical area for the study of the Miocene land mammal faunas and includes one of the densest and most continuous records in Eurasia. Furthermore, it is the type area for the Vallesian European land mammal age. After decades of study a huge amount of bio- and magnetostratigraphic data have been collected, allowing an unprecedented dating accuracy. Here we provide an updated local biostratigraphy for the late Aragonian, Vallesian and Turolian of the Vallès-Penedès Basin. This new biostratigraphic scheme is almost exclusively based on fossil rodents, which are the most abundant and one of the best known mammal orders in the area. Our proposal represents a significant refinement compared to previous attempts and provides a formal diagnosis and description of each zone, as well as clear definition of boundaries and a reference locality and section. The chronology of zone boundaries and main bioevents is based on detailed magnetostratigraphic data. The defined biozones allow for the correlation of the sites without associated magnetostratigraphical data. Finally, the correlation of the Vallès-Penedès local zones with other detailed local biostratigraphies, such as those of the Calatayud-Montalbán and Teruel basins (east-central Spain) is discussed. The sequence and chronology of the main bioevents is roughly comparable, although the rodent succession and the structure of the assemblage show important differences between these areas. (Author)

  11. Bibliography of literature pertaining to Long Valley Caldera and associated volcanic fields

    Science.gov (United States)

    Ewert, John W.; Harpel, Christopher J.; Brooks, Suzanna K.; Marcaida, Mae

    2011-01-01

    On May 25-27, 1980, Long Valley caldera was rocked by four M=6 earthquakes that heralded the onset of a wave of seismic activity within the caldera which has continued through the present. Unrest has taken the form of seismic swarms, uplift of the resurgent dome, and areas of vegetation killed by increased CO2 emissions, all interpreted as resulting from magma injection into different levels beneath the caldera, as well as beneath Mammoth Mountain along the southwest rim of the caldera. Continuing economic development in the Mammoth Lakes area has swelled the local population, increasing the risk to people and property if an eruption were to occur. The U.S. Geological Survey (USGS) has been monitoring geophysical activity in the Long Valley area since the mid-1970s and continues to track the unrest in real time with a sophisticated network of geophysical sensors. Hazards information obtained by this monitoring is provided to local, State, and Federal officials and to the public through the Long Valley Observatory. The Long Valley area also was scientifically important before the onset of current unrest. Lying at the eastern foot of the Sierra Nevada, the deposits from this active volcanic system have provided fertile ground for research into Neogene tectonics, Quaternary geology and geomorphology, regional stratigraphy, and volcanology. In the early 1970s, intensive studies of the area began through the USGS Geothermal Investigations Program, owing to the presence of a large young silicic volcanic system. The paroxysmal eruption of Long Valley caldera about 760,000 years ago produced the Bishop Tuff and associated Bishop ash. The Bishop Tuff is a well-preserved ignimbrite deposit that has continued to provide new and developing insights into the dynamics of ignimbrite-forming eruptions. Another extremely important aspect of the Bishop Tuff is that it is the oldest known normally magnetized unit of the Brunhes Chron. Thus, the age of the Bishop Tuff is used to

  12. Fauna anfibia del valle de sibundoy, putumayo-colombia

    OpenAIRE

    MUESES-CISNEROS, JONH JAIRO

    2012-01-01

    La fauna Amphibia del Valle de Sibundoy consta de 32 especies agrupadas en dos órdenes, cinco familias y siete géneros. De éstas, cinco son especies nuevas cuya descripción se encuentra en proceso. Se amplía el límite altitudinal de otras siete y se presentan tres más para ser incluidas en la lista de anfibios de Colombia. A pesar de que en el lugar se han realizado colectas herpetológicas desde finales de los años sesenta, este estudio es el primero que se realiza en el Putumayo (uno de los ...

  13. Modelling ground movements at Campi Flegrei caldera (Italy): the role of the shallow geothermal system

    Science.gov (United States)

    Troiano, Antonio; Giulia di Giuseppe, Maria; Petrillo, Zaccaria; Troise, Claudia; de Natale, Giuseppe

    2010-05-01

    Campi Flegrei caldera is characterized by large ground movements, well known since Roman times. Superimposed to a general secular subsidence occurring at a rate of 1.5-2.0 cm/year, an episode of sharp uplift is in progress since 1969, with peak rates up to 1 m/year (in 1982-1984), similar to another episode which culminated with the 1538 eruption. Peak uplift episodes are often followed by some amount of subsidence, which prevent a simple interpretation in terms of purely magmatic inflation phenomena. Such up and down episodes of ground deformations are rather common at large calderas, like in Yellowstone (USA), Long Valley (USA), etc. Here we propose an interpretation based on a mixed mechanical-fluid-dynamical model, in which part of the uplift is generated by increase of water pressure in the shallow geothermal system, as a response to rapid inflow of magmatic fluids exsolved from a deeper magma chamber. We use the program THOUGH2 to model the changes of temperature and pressure in the geothermal system due to the magmatic fluids inflow. Changes in pressure in the caldera volume are then used to compute ground deformations. This way, a theoretical time evolution of ground deformation has been obtained, which compares well with the observed one, if appropriate values of permeability are used. We discuss the implication of such a model for eruption forecast purposes, and the extent at which the required values of permeability can be really representative of the real medium.

  14. Hydrology of the Upper-Garonne basin (Valle de Arán, Spain)

    NARCIS (Netherlands)

    Rijckborst, H.

    1967-01-01

    The runoff in the Valle de Arán, which is a steep and high mountain basin in the Pyrenees, consists essentially of baseflow, and fast runoff is only a minor phenomenon. The baseflow is related to areas of scree and forest, and the percentage of the precipitation which contributes to the fast runoff,

  15. Mismi y Huarancante: nevados sagrados del Valle de Colca.

    OpenAIRE

    Ceruti, María Constanza

    2013-01-01

    El presente trabajo hace referencia a ascensiones efectuadas por la autora a las cimas de los montes Mismi (5596 m) y Huarancante (5360 m), en el sur de Perú. Ambas montañas ostentan evidencias de sitios rituales de altura de probable filiación Inca en avanzado estado de destrucción por eventos de huaqueo que se remontan a fines de la década del setenta. Al igual que otros nevados que flanquean al valle de Colca, el Huarancante y el Mismi siguen ...

  16. Variabilidad genética de Hartón del Valle mediante RAM Genetic variability of Harton del Valle by RAM

    Directory of Open Access Journals (Sweden)

    Ana M Piedrahíta

    2008-01-01

    Full Text Available El Hartón del Valle (HV hace parte de las siete razas criollas de ganado bovino colombiano y de acuerdo con los criterios de la FAO está considerado como vulnerable. Para estudiar su variabilidad genética fueron muestreados 33 individuos HV y tres animales de la raza Holstein, como control externo. Se extrajo ADN utilizando el método de Salting Out y las muestras fueron analizadas mediante la técnica molecular RAM (Randon amplified microsatellites. Se utilizaron los cebadores CGA, CCA, TG, y CT. El valor promedio de heterocigosidad esperada fue de 0.26 y el F ST fue 0.39 ± 0.03. Con el índice de Dice-Nei Li y agrupando con el método UPGMA se distinguieron dos grupos: uno integrado por dos hatos de conservación y el otro por cuatro fincas que han compartido reproductores.Harton del Valle (HV breed belong to the seven Creole breeds of the Colombian bovine livestock, according to FAO criteria it is considered as vulnerable. To study its genetical variability, 33 HV animals and three and 3 animals of Holstein breed as a external control were sampled. Simples of DNA were isolated using the Salting Out method and RAM (Random amplified microsatellites technique was used. CGA, CCA, TG and CT primers were used. The mean value of expected heterocigozity was 0.26 and F ST fue 0.39 ± 0.03. Using Dice-Nei Li index and UPGMA clustering method, two groups were distinguished: the first one integrated for two conservation herds and other one by tour faros that have been sharing breeding bulls.

  17. The Effects of Vent Location, Event Scale, and Time Forecasts on Pyroclastic Density Current Hazard Maps at Campi Flegrei Caldera (Italy

    Directory of Open Access Journals (Sweden)

    Andrea Bevilacqua

    2017-09-01

    Full Text Available This study presents a new method for producing long-term hazard maps for pyroclastic density currents (PDC originating at Campi Flegrei caldera. Such method is based on a doubly stochastic approach and is able to combine the uncertainty assessments on the spatial location of the volcanic vent, the size of the flow and the expected time of such an event. The results are obtained by using a Monte Carlo approach and adopting a simplified invasion model based on the box model integral approximation. Temporal assessments are modeled through a Cox-type process including self-excitement effects, based on the eruptive record of the last 15 kyr. Mean and percentile maps of PDC invasion probability are produced, exploring their sensitivity to some sources of uncertainty and to the effects of the dependence between PDC scales and the caldera sector where they originated. Conditional maps representative of PDC originating inside limited zones of the caldera, or of PDC with a limited range of scales are also produced. Finally, the effect of assuming different time windows for the hazard estimates is explored, also including the potential occurrence of a sequence of multiple events. Assuming that the last eruption of Monte Nuovo (A.D. 1538 marked the beginning of a new epoch of activity similar to the previous ones, results of the statistical analysis indicate a mean probability of PDC invasion above 5% in the next 50 years on almost the entire caldera (with a probability peak of ~25% in the central part of the caldera. In contrast, probability values reduce by a factor of about 3 if the entire eruptive record is considered over the last 15 kyr, i.e., including both eruptive epochs and quiescent periods.

  18. The effect of pressurized magma chamber growth on melt migration and pre-caldera vent locations through time at Mount Mazama, Crater Lake, Oregon

    Science.gov (United States)

    Karlstrom, Leif; Wright, Heather M.; Bacon, Charles R.

    2015-01-01

    The pattern of eruptions at long-lived volcanic centers provides a window into the co-evolution of crustal magma transport, tectonic stresses, and unsteady magma generation at depth. Mount Mazama in the Oregon Cascades has seen variable activity over the last 400 ky, including the 50 km3 climactic eruption at ca. 7.7 ka that produced Crater Lake caldera. The physical mechanisms responsible for the assembly of silicic magma reservoirs that are the precursors to caldera-forming eruptions are poorly understood. Here we argue that the spatial and temporal distribution of geographically clustered volcanic vents near Mazama reflects the development of a centralized magma chamber that fed the climactic eruption. Time-averaged eruption rates at Mount Mazama imply an order of magnitude increase in deep magma influx prior to the caldera-forming event, suggesting that unsteady mantle melting triggered a chamber growth episode that culminated in caldera formation. We model magma chamber–dike interactions over ∼50 ky preceding the climactic eruption to fit the observed distribution of surface eruptive vents in space and time, as well as petrologically estimated deep influx rates. Best fitting models predict an expanding zone of dike capture caused by a growing, oblate spheroidal magma chamber with 10–30 MPa of overpressure. This growing zone of chamber influence causes closest approaching regional mafic vent locations as well as more compositionally evolved Mazama eruptions to migrate away from the climactic eruptive center, returning as observed to the center after the chamber drains during the caldera-forming eruption.

  19. Developing tourism facilities based on geotourism in Silalahi Village, Geopark Toba Caldera

    Science.gov (United States)

    Ginting, Nurlisa; Sasmita, Anggun

    2018-03-01

    Toba Caldera is one of the biggest lakes in Indonesia with supervolcano geology phenomenon, and its result amazing natural resources. It makes Toba Lake become the number one tourism in North Sumatera. However, tourism in Toba Lake is still needed development. Geotourism is one of the concept that suitable for this case. It is because geotourism is a new development tourism concept that focuses on the natural and geological phenomenon. Silalahi Village is one of the areas in Toba Caldera that still needs development, especially in tourism facilities sector. This research aims to investigation the facilities concept based on geotourism in Silalahi Village that would be analyzed by three element of tourism facilities namely, accommodation, support facilities and tourism auxiliary facilities. The method used for this research is mixed methods by distributing 100 questionnaires, observations directly to the area and interviews with three informants related parties interested in tourism, such as local people, government, and academics. The data would be processed and analyzed with techniques of exploration. The result shows that the three elements of tourism facilities are still lacking and needs to improve to increase the economy and tourism in the area.

  20. Multi-stage volcanic island flank collapses with coeval explosive caldera-forming eruptions.

    Science.gov (United States)

    Hunt, James E; Cassidy, Michael; Talling, Peter J

    2018-01-18

    Volcanic flank collapses and explosive eruptions are among the largest and most destructive processes on Earth. Events at Mount St. Helens in May 1980 demonstrated how a relatively small (300 km 3 ), but can also occur in complex multiple stages. Here, we show that multistage retrogressive landslides on Tenerife triggered explosive caldera-forming eruptions, including the Diego Hernandez, Guajara and Ucanca caldera eruptions. Geochemical analyses were performed on volcanic glasses recovered from marine sedimentary deposits, called turbidites, associated with each individual stage of each multistage landslide. These analyses indicate only the lattermost stages of subaerial flank failure contain materials originating from respective coeval explosive eruption, suggesting that initial more voluminous submarine stages of multi-stage flank collapse induce these aforementioned explosive eruption. Furthermore, there are extended time lags identified between the individual stages of multi-stage collapse, and thus an extended time lag between the initial submarine stages of failure and the onset of subsequent explosive eruption. This time lag succeeding landslide-generated static decompression has implications for the response of magmatic systems to un-roofing and poses a significant implication for ocean island volcanism and civil emergency planning.

  1. Limited role for thermal erosion by turbulent lava in proximal Athabasca Valles, Mars

    Science.gov (United States)

    Cataldo, Vincenzo; Williams, David A.; Dundas, Colin M.; Kestay, Laszlo P.

    2015-01-01

    The Athabasca Valles flood lava is among the most recent (Mars and was probably emplaced turbulently. The Williams et al. (2005) model of thermal erosion by lava has been applied to what we term “proximal Athabasca,” the 75 km long upstream portion of Athabasca Valles. For emplacement volumes of 5000 and 7500 km3and average flow thicknesses of 20 and 30 m, the duration of the eruption varies between ~11 and ~37 days. The erosion of the lava flow substrate is investigated for three eruption temperatures (1270°C, 1260°C, and 1250°C), and volatile contents equivalent to 0–65 vol % bubbles. The largest erosion depths of ~3.8–7.5 m are at the lava source, for 20 m thick and bubble-free flows that erupted at their liquidus temperature (1270°C). A substrate containing 25 vol % ice leads to maximum erosion. A lava temperature 20°C below liquidus reduces erosion depths by a factor of ~2.2. If flow viscosity increases with increasing bubble content in the lava, the presence of 30–50 vol % bubbles leads to erosion depths lower than those relative to bubble-free lava by a factor of ~2.4. The presence of 25 vol % ice in the substrate increases erosion depths by a factor of 1.3. Nevertheless, modeled erosion depths, consistent with the emplacement volume and flow duration constraints, are far less than the depth of the channel (~35–100 m). We conclude that thermal erosion does not appear to have had a major role in excavating Athabasca Valles.

  2. Del Horizonte Medio al Horizonte Tardío en la Costa Sur Central: el caso del valle de Asia

    Directory of Open Access Journals (Sweden)

    2004-01-01

    Full Text Available DE L’HORIZON MOYEN A L’HORIZON RECENT SUR LA COTE CENTRALE : LE CAS DE LA VALLEE DE ASIA. La vallée de Asia, située à quelque 100 km au sud de Lima, a joué un rôle important durant l’Horizon moyen. En effet, les contextes funéraires de la Huaca Malena et les textiles élaborés qui en sont issus, suggèrent d’étroites relations avec Huari, Pachacamac, et les côtes centrale et nord. L’étude des textiles nous permet de voir que la transition de l’Horizon moyen à la période Intermédiaire récent se marque par une croissance des relations avec la côte centrale. Selon les données ethnohistoriques, la vallée de Asia était durant la période Intermédiaire récent habitée par les Coyallo, qui versaient tribut à Pachacamac. À l’Horizon récent, les Incas construisirent d’importants centres administratifs dans la vallée, et durant cette période le matériel céramique montre de fortes relations avec les styles des vallées voisines au nord, comme Mala, Chilca, et la côte aux alentours de Lima. El valle de Asia, situado a 100 kilómetros al sur de Lima, jugó un rol de importancia durante el Horizonte Medio. En efecto, los contextos funerarios de Huaca Malena, así como los finos textiles que los acompañan indican una fuerte relación con Wari, Pachacamac, la Costa Central y la Costa Norte. De acuerdo con la evidencia textil, el tránsito del Horizonte Medio al periodo Intermedio Tardío incrementó las relaciones con la costa central. Para el periodo Intermedio Tardío, de acuerdo a la información etnohistórica, el valle estuvo habitado por los coayllo, quienes tributaban a Pachacamac. Durante el Horizonte Tardío, los incas construyen importantes centros administrativos en el valle, y la cerámica durante este periodo se relacionó fuertemente con los estilos propios de los vecinos valles norteños de Mala, Chilca y la costa de Lima. FROM THE MIDDLE HORIZON TO THE LATE HORIZON ON THE SOUTH CENTRAL COAST: THE CASE OF THE

  3. Intercambio cationico calcio-magnesio-sodio en algunos suelos del Valle del Cauca

    Directory of Open Access Journals (Sweden)

    Torres M. Jorge Ilian

    1989-12-01

    Full Text Available Para estudiar la influencia de diferentes cantidades de Ca, Mg y Na en las aguas de riego sobre las propiedades químicas y físicas de los suelos, se caracterizó el intercambio Ca-Mg en presencia de diferentes saturaciones de Na en la solución de equilibrio en términos de las isotemas de intercambio de 4 suelos pertenecientes a los tres principales ordenes predominantes en el Valle del Cauca. En general hubo ligera preferencia por Ca sobre Mg en los suelos; pero a bajas concentraciones de Mg en la solución el suelo Doronzoro mostró preferencia por Mg y el suelo Crucero una tendencia hacia mayor afinidad por el Mg+2a altos valores de Mg y de la RAS en la solución. Las preferencias de los suelos por Mg parecen estar asociadas en parte con la presencia de carbonatos y materia orgánica. Con excepción del suelo Crucero, las isotermas no mostraron influencia de la RAS o del PSI resultante sobre la selectividad por Ca+2 o Mg+2. Las altas saturaciones de Mg+2 encontradas en muchos suelos del Valle del Cauca se deben a la presencia de altas cantidades de este ión en las aguas de riego en las aguas freáticas y no a preferencia de los suelos por el mismo.To study the influence of different amounts of Ca, Mg and Na in the irrigation water on chemical and physical properties of soils, four soils from the Cauca Valle y were used to characterize their cation distribution and the Ca-Mg exchange in presence of different concentrations of Na in the equilibrium solution. A general preference for Ca over Mg was found; however, the Doronzoro soil isotherms showed that at low ion concentrations of Mg in the solutions there is a preference for Mg2+relative to Ca2+ and Crucero soil showed an increasing affinity to Mg2+as its concentration and SAR increase in the solution. Soil preferences for magnesium seem to be related to the presence of organic matter or to the presence of carbonates. Excluding the Crucero soil the isotherms did not show influence of SAR

  4. Real-time monitoring of seismicity and deformation during the Bárdarbunga rifting event and associated caldera subsidence

    Science.gov (United States)

    Jónsdóttir, Kristín; Ófeigsson, Benedikt; Vogfjörd, Kristín; Roberts, Matthew; Barsotti, Sara; Gudmundsson, Gunnar; Hensch, Martin; Bergsson, Bergur; Kjartansson, vilhjálmur; Erlendsson, Pálmi; Friðriksdóttir, Hildur; Hreinsdóttir, Sigrún; Guðmundsson, Magnús; Sigmundsson, Freysteinn; Árnadóttir, Thóra; Heimisson, Elías; Hjorleifsdóttir, Vala; Soring, Jón; Björnsson, Bogi; Oddsson, Björn

    2015-04-01

    We present a monitoring overview of a rifting event and associated caldera subsidence in a glaciated environment during the Bárðarbunga volcanic crisis. Following a slight increase in seismicity and a weak deformation signal, noticed a few months before the unrest by the SIL monitoring team, an intense seismic swarm began in the subglacial Bárðarbunga caldera on August 16 2014. During the following two weeks, a dyke intruded into the crust beneath the Vatnajökull ice cap, propagating 48 km from the caldera to the east-north-east and north of the glacier where an effusive eruption started in Holuhraun. The eruption is still ongoing at the time of writing and has become the largest eruption in over 200 years in Iceland. The dyke propagation was episodic with a variable rate and on several occasions low frequency seismic tremor was observed. Four ice cauldrons, manifestations of small subglacial eruptions, were detected. Soon after the swarm began the 7x11 km wide caldera started to subside and is still subsiding (although at slower rates) and has in total subsided over 60 meters. Unrest in subglacial volcanoes always calls for interdisciplinary efforts and teamwork plays a key role for efficient monitoring. Iceland has experienced six subglacial volcanic crises since modern digital monitoring started in the early 90s. With every crisis the monitoring capabilities, data interpretations, communication and information dissemination procedures have improved. The Civil Protection calls for a board of experts and scientists (Civil Protection Science Board, CPSB) to share their knowledge and provide up-to-date information on the current status of the volcano, the relevant hazards and most likely scenarios. The evolution of the rifting was monitored in real-time by the joint interpretation of seismic and cGPS data. The dyke propagation could be tracked and new, updated models of the dyke volume were presented at the CPSB meetings, often daily. In addition, deformation

  5. Las palmeras en los valles principales de la Amazonia peruana

    Directory of Open Access Journals (Sweden)

    1992-01-01

    Full Text Available LES PALMIERS DES PRINCIPALES VALLEES DE L’AMAZONIE PERUVIENNE. La distribution géographique des espèces de palmiers de l’Amazonie péruvienne est présentée selon les principales vallées. Pour chaque affluent important est donnée la liste des espèces récoltées, et pour chaque espèce sont réunies les références des échantillons d’herbiers, collecteur(s et numéro de collection, ainsi que les herbiers de dépôt. Se presenta la distribución de las palmeras de la Amazonia en función de los valles principales. Por cada río de mayor importancia, se da la lista de las especies colectadas, las referencias de las muestras botánicas, colector(es y número de colección, y los herbarios de depósito de dichas muestras. PALMS OF THE MAJOR RIVER VALLEYS OF PERUVIAN AMAZONIA. Palm species distribution in Peruvian Amazonia is presented according to the major river valleys. The species collected are listed for each tributary valley. The collection references, collector(s and number of the specimen and the herbaria of deposit are given for each species.

  6. 4D imaging of the source of ground deformation at Campi Flegrei caldera (Italy) during recent unrest episodes

    Science.gov (United States)

    D'Auria, L.; Giudicepietro, F.; Martini, M.; Lanari, R.

    2011-12-01

    Campi Flegrei caldera, has been affected in recent decades by three episodes of significant ground uplift. After the last crisis (1982-84), which was accompanied by strong seismicity, the ground has shown a general descending trend, occasionally interrupted by minor uplift episodes, together with low-magnitude volcano-tectonic and long-period seismicity. We assume that the source of minor ground deformations consists in a diffuse volumetric source, related to both thermoelastic and poroelastic strain. This is a reasonable assumption considering that Campi Flegrei are known to host a geothermal reservoir. We have inverted a DInSAR dataset spanning the interval 1995-2008. Results show that the geometry of the source is much more complex than previously recognized and, most important, it shows significant temporal variations, within few months. The deformation source, of the analyzed uplift episodes, starts with a volumetric expansion centered at a depth of about 5 km. The position of this volume is close to the caldera rims. Later the expansion migrates upward, reaching the surface along preferred paths, leading to the Solfatara area, located almost at the center of the caldera. This area is well known for its powerful geothermal emissions. During the upward migration, seismic long-period sources are activated. Their location is consistent with the path identified by the inversion of the DInSAR dataset. We infer, that this dynamics is linked to the injection of hot fluid batches, along the caldera rims and their upward migration, following preferential high permeability paths. Furthermore we have identified an injection episode which has not been previously recognized. The deformation source remains at depth slowly waning in few years. We show how this conceptual framework fits well with the observed geodetic, seismic and geochemical data.

  7. Monitoring unrest in a large silicic caldera, the long Valley-inyo craters volcanic complex in east-central California

    Science.gov (United States)

    Hill, D. P.

    1984-06-01

    Recent patterns of geologic unrest in long Valley caldera in east-central California emphasize that this large, silicic volcanic system and the adjacent, geologically youthful Inyo-Mono Craters volcanic chain are still active and capable of producing locally hazardous volcanic eruptions. A series of four magnitude -6 earthquakes in May 1980 called attention to this current episode of unrest, and subsequent activity has included numerous earthquake swarms in the south moat of the caldera accompanied by inflation of the resurgent dome by more than 50 cm over the last five years. The seismicity associated with this unrest is currently monitored by a network of 31 telemetered seismic stations with an automatic processing system that yelds hypocentral locations and earthquake magnitudes in near-real time. Deformation of the ground is monitored by a) a series of overlapping trilateration networks that provide coverage ranging from annual measurements of regional deformation to daily measurements of deformation local to the active, southern section of the caldera, b) a regional network of level lines surveyed annually, c) a regional network of precise gravity stations occupied annually, d) local, L-shaped level figures surveyed every few months, and e) a network of fourteen borehole tiltmeter clusters (two instruments in each cluster) and a borehole dilatometer, the telemetered signals from which provide continuous data on deformation rates. Additional telemetered data provide continuous information on fluctuations in the local magnetic field, hydrogen gas emission rates at three sites, and water level and temperatures in three wells. Continuous data on disharge rates and temperatures from hot springs and fumaroles are collected by several on-site recorders within the caldera, and samples for liquid and gas chemistry are collected several times per year from selected hot springs and fumaroles.

  8. The Campi Flegrei Deep Drilling Project: using borehole measurements to discriminate magmatic and geothermal effects in caldera unrest

    Science.gov (United States)

    De Natale, Giuseppe; Troise, Claudia; Carlino, Stefano; Troiano, Antonio; Giulia Di Giuseppe, Maria; Piochi, Monica; Somma, Renato; Tramelli, Anna; Kilburn, Christopher

    2015-04-01

    Large calderas are potentially the most risky volcanic areas in the world since they are capable of producing huge eruptions whose major effects can involve human life and activities from regional to global scale. Calderas worldwide are characterized by frequent episodes of unrest which, only in few cases, culminate with eruptions. This ambiguous behavior is generally explained in terms of magma intrusion or disturbance of geothermal fluids in the shallow crust, which are both source of ground deformations and seismicity. A major goal is to determine the relative contribution of each process, because the potential for eruptions significantly enhanced if magma movements emerge as the primary component. A very important case study is the active Campi Flegrei caldera, hosting part of the large city of Naples (Southern Italy). In the framework of the Campi Flegrei Deep Drilling Project new filed data from pilot borehole have been recorded (permeability and in situ stress) by using a novel procedure of Leak Off Test. These new data, particularly the actual permeability, are fundamental to calibrate the caldera unrest models at Campi Flegrei and, , to put constrains to forecast the maximum future eruptive scenario. We show here that these new data, integrated by fluid-dynamical modeling, allow to assess that only about a third of the maximum uplift recorded in 1982-1984 may be due to shallow aquifer perturbation, so that the remaining part should be due to magma inflow, corresponding to about 0.05 Km3 of new magma if we assume a sill-like reservoir located at 4 km of depth. Considering an almost equivalent magma inflow for the 1969-1972 unrest, which showed a similar uplift, we got a total magma inflow of 0.1 Km3. It is then very important to assess the times for cooling of such accumulated magma, in order to assess the eruption hazard.

  9. Genotoxicidad sobre linfocitos humanos expuestos a PM10 de tres sitios del Valle de Aburrá (Antioquia)

    OpenAIRE

    Mendoza-Zapata, Lady C.; Orozco-Jiménez, Luz Y.; Zapata-Restrepo, Lina M.; Palacio-Baena, Jaime A.

    2013-01-01

    Objetivo Evaluar la calidad del aire en tres sitios del Valle de Aburrá (Antioquia) a través de la determinación de la genotoxicidad del PM10 en linfocitos humanos. Métodos A partir del valor de referencia de PM10 para Colombia (50 μg/m3/año) se eligieron tres sitios del Valle de Aburrá con diferente promedio de PM10, Barbosa con 25 μg/m3, Corantioquia con 44 μg/m3y Facultad de Minas con 91 μg/m3. Los filtros de PM10 expuestos por 24 horas, se analizaron en la épocas de lluvia, transición y s...

  10. Genotoxicidad sobre linfocitos humanos expuestos a pm10 de tres sitios del valle de aburrá (antioquia)

    OpenAIRE

    Mendoza, Lady Carolina; Orozco Jimenez, luz Yaneth; Zapata Restrepo, Lina Maria; Palacio Baena, Jaime Alberto

    2013-01-01

    Objetivo Evaluar la calidad del aire en tres sitios del Valle de Aburrá (Antioquia) a través de la determinación de la genotoxicidad del PM10 en linfocitos humanos.Métodos A partir del valor de referencia de PM10 para Colombia (50 μg/m3/año) se eligieron tres sitios del Valle de Aburrá con diferente promedio de PM10, Barbosa con 25 μg/m3, Corantioquia con 44 μg/m3y Facultad de Minas con 91 μg/m3. Los filtros de PM10 expuestos por 24 horas, se analizaron en la épocas de lluvia, transición y se...

  11. Prevalence of Strongylida nematodes associated with African Snail, Achatina fulica, in Valle del Cauca, Colombia

    Directory of Open Access Journals (Sweden)

    Diego Córdoba-R

    2017-09-01

    Full Text Available Objectives. To establish the presence and prevalence of Strongylida nematode parasites in Achatina fulica in the Valle del Cauca, especially of nematodes that are potentially pathogenic for humans. Materials and methods. A. fulica individuals were collected in nine cities of the Valle del Cauca, Colombia. Direct visual examination was used to identify A. fulica parasites. Nematodes were separated from tissue or collected from mucus, washed in saline solution, and fixed in a hot AFA solution. Samples were mounted in glycerine and observed under the microscope. Results. The general nematode parasite prevalence was 35% in 2013. The city with highest prevalence during 2013 was Cartago (60%, following by Buenaventura (42.9% and Cali (33%, while during 2014 were Cali (30% and Buenaventura (30%. The Strongylida nematodes registered were classified in three genera: Angiostrongylus (14.7% prevalence, Aelurostrongylus (2.6%,and Strongyluris (2.6%. The city with highest positive records of Angiostrongylus was Cali during 2014 and Aelurostrongylus was Buenaventura during 2013. Strongyluris genus was recorded only in Cali during 2013, with a prevalence of 11%. Of the nine evaluated cities, five has presence of Angiostrongylus. Conclusions. Three genera of Strongylida nematode were recorded associated with A. fulicas specimens in the Valle del Cauca during 2013 and 2014. Therefore, the role that A. fulica and native mollusk species could be playing in the life cycle of these parasites at the local level should not underestimated.

  12. Relationship between beta lactoglobulin and subclinical mastitis in Valle del Belice sheep breed

    NARCIS (Netherlands)

    Gigli, I.; Riggio, V.; Monteleone, G.; Cacioppo, D.; Rosa, A.J.M.; Maizon, D.O.

    2007-01-01

    The objective of the following research was to determine the effect of LGB genotypes on subclinical mastitis in Valle del Belice dairy sheep. Ewes were classified as affected or not by subclinical mastitis within a lactation based on i) a positive culture in one of the test-days and ii) more than

  13. Genetic variability of Harton del Valle by RAM Variabilidad genética de Hartón del Valle mediante RAM

    Directory of Open Access Journals (Sweden)

    Alvarez Franco Luz Angela

    2008-03-01

    Full Text Available Harton del Valle (HV breed belong to the seven Creole breeds of the Colombian bovine livestock, according to FAO criteria it is considered as vulnerable. To study its genetical variability, 33 HV animals and three and 3 animals of Holstein breed as a external control were sampled. Simples of DNA were isolated using the Salting Out method and RAM (Random amplified microsatellites technique was used. CGA, CCA, TG and CT primers were used. The mean value of expected heterocigozity was 0.26 and FST fue 0.39 ± 0.03. Using Dice–Nei Li index and UPGMA clustering method, two groups were distinguished: the first one integrated for two conservation herds and other one by tour faros that have been sharing breeding bulls.El Hartón del Valle (HV hace parte de las siete razas criollas de ganado bovino colombiano y de acuerdo con los criterios de la FAO está considerado como vulnerable. Para estudiar su variabilidad genética fueron muestreados 33 individuos HV y tres animales de la raza Holstein, como control externo. Se extrajo ADN utilizando el método de Salting Out y las muestras fueron analizadas mediante la técnica molecular RAM (Randon amplified microsatellites. Se utilizaron los cebadores CGA, CCA, TG, y CT. El valor promedio de heterocigosidad esperada fue de 0.26 y el FST fue 0.39 ± 0.03. Con el índice de Dice–Nei Li y agrupando con el método UPGMA se distinguieron dos grupos: uno integrado por dos hatos de conservación y el otro por cuatro fincas que han compartido reproductores.

  14. [Detection of Aedes albopictus (Skuse) (Diptera: Culicidae) in the city of Cali, Valle del Cauca, Colombia].

    Science.gov (United States)

    Cuéllar-Jiménez, María Elena; Velásquez-Escobar, Olga Lucía; González-Obando, Ranulfo; Morales-Reichmann, Carlos Andrés

    2007-06-01

    Aedes albopictus is the second most important dengue virus vector in the Asian southeast after Aedes aegypti. Its entrance into the Americas occurred in 1985, and laboratory studies performed show its potential as a vector in this continent as well. In Colombia, this species has been reported in Leticia (Amazonas) in 1998 and Buenaventura (Valle del Cauca) in 2001. The latest discoveries show that this mosquito continues to advance toward the country's interior. To inform that the presence of A. albopictus is documented in the city of Cali, Valle del Cauca, Colombia. Since 2002, weekly sampling has been performed using larval traps located at seventeen stations. The identification of the A. albopictus species, was carried out in the Unidad de Entomología, Laboratorio de Salud Pública Departamental. These identifications were confirmed in the Entomology Laboratory at Universidad del Valle and the National Institute of Health in Bogotá. From April to June of 2006, larvae of A. albopictus were found in six sampling stations located between northwest and northeast of Cali, one of them in the suburban area of the Yumbo city. The control of A. aegypti and A. albopictus must be integrated into a single program. The surveillance in the cities and nearest departments must be intensified with the objective of limiting the advancement of A. albopictus.

  15. Multidisciplinary study (CO2 flux, ERT, self-potential, permeability and structural surveys) in Fondi di Baia, Astroni and Agnano volcanoes: insights for the structural architecture of the Campi Flegrei caldera (southern Italy)

    Science.gov (United States)

    Isaia, Roberto; Carapezza, Maria Luisa; Conti, Eric; Giulia Di Giuseppe, Maria; Lucchetti, Carlo; Prinzi, Ernesto; Ranaldi, Massimo; Tarchini, Luca; Tramparulo, Francesco; Troiano, Antonio; Vitale, Stefano; Cascella, Enrico; Castello, Nicola; Cicatiello, Alessandro; Maiolino, Marco; Puzio, Domenico; Tazza, Lucia; Villani, Roberto

    2017-04-01

    Recent volcanism at Campi Flegrei caldera produced more than 70 eruptions in the last 15 ka formed different volcanic edifices. The vent distribution was related to the main volcano-tectonic structure active in the caldera along which also concentrated part of the present hydrothermal and fumarolic activity, such as in the Solfatara area. In order to define the role of major faults in the Campi Flegrei Caldera, we analyzed some volcanic craters (Fondi di Baia and Astroni) and the Agnano caldera, by means of different geochemical and geophysical technics including CO2 flux, electrical resistivity (ERT), self-potential and permeability surveys. We provided some ERT profiles and different maps of geochemical and geophysical features. Major fault planes were identified comparing ERT imaging with alignments of anomalies in maps. The results can improve the knowledge on the present state of these volcanoes actually not fully monitored though included in the area with high probability of future vent opening within the Campi Flegrei caldera.

  16. Overview for geologic field-trip guides to Mount Mazama, Crater Lake Caldera, and Newberry Volcano, Oregon

    Science.gov (United States)

    Bacon, Charles R.; Donnelly-Nolan, Julie M.; Jensen, Robert A.; Wright, Heather M.

    2017-08-16

    These field-trip guides were written for the occasion of the International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI) quadrennial scientific assembly in Portland, Oregon, in August 2017. The guide to Mount Mazama and Crater Lake caldera is an updated and expanded version of the guide (Bacon, 1989) for part of an earlier IAVCEI trip to the southern Cascade Range. The guide to Newberry Volcano describes the stops included in the 2017 field trip. Crater Lake and Newberry are the two best-preserved and most recent calderas in the Cascades Volcanic Arc. Although located in different settings in the arc, with Crater Lake on the arc axis and Newberry in the rear-arc, both volcanoes are located at the intersection of the arc and the northwest corner region of the extensional Basin and Range Province.

  17. Diagnóstico y propuesta para una gestión integral del riesgo en el valle de aburra: red riesgos

    OpenAIRE

    ARISTIZÁBAL, EDIER; VARGAS, RICHARD

    2010-01-01

    A partir del análisis de la situación organizacional de las diferentes instituciones en el Valle de Aburrá frente a la reducción de desastres y emergencias asociadas con los fenómenos de origen natural y antrópico, el Área Metropolitana del Valle de Aburrá, como autoridad ambiental y entidad planificadora, hace una propuesta que pretende articular todas las entidades, organizaciones e instituciones públicas y privadas hacia una gestión integral del riesgo, y la cual denominó: Red para la Gest...

  18. Agroindustrial waste valorization - fruits - in Medellin and the south of Valle de Aburra, Colombia

    International Nuclear Information System (INIS)

    Yepes, Sandra Milena; Montoya Naranjo, Lina Johana; Orozco Sanchez, Fernando

    2008-01-01

    Industrial residues continuing being and economic problem so companies have to assume high costs to manage them. Such is the case of large amounts of fruit residues produced in Medellin, city and surroundings due to a great number of companies of this groindustrial sector. In this work a scan was made in Medellin and the South of Valle de Aburra to know the current problem of these residues. Subsequently a physical-chemistry characterization of the most representative residues with the purpose to propose different alternative uses. The main residues of the interviewed companies come from orange, guava, guanabana and mango. The main valorization processes include compost, worms culture and obtaining chemical products. Only with the interviewed companies, plants of waste valorization could be mounted with prosecution capacity from 9 to 375 ton/month depending on process. If all of the residues generated in Medellin and the South of the Valle de Aburra were used, the capacity of these valorization plants could multiply for 20.

  19. Natural radionuclides in the rocks of the Valle del Cervo Pluton in Piedmont.

    Science.gov (United States)

    Sesana, Lucia; Fumagalli, Marco; Carnevale, Mauro; Polla, Giancarla; Facchini, Ugo; Colombo, Annita; Tunesi, Annalisa; De Capitani, Luisa; Rusconi, Rosella

    2006-01-01

    Monitoring of the gamma radiation in Valle del Cervo Pluton was performed by determining U and Th contents in the main rock types cropping out over the entire area and pertaining to the granitic complex, syenitic complex and monzonitic complex. In particular, syenitic rocks were largely used as building and ornamental materials (e.g. Sienite della Balma). All the samples are fresh and do not present joints or fractures filled with U minerals. In the crushed samples the activity of uranium varies from 346 to 764 Bq/kg. Concentration of thorium varies from 202 to 478 Bq/kg. For all the analysed rocks uranium activity is higher than thorium one. The lowest value of radioactive concentration is referred to rocks of the granitic complex. The most active rocks are syenites. The data confirm the high activities of Valle del Cervo rock types, strongly connected with high K content of the source magma (geochemical signature); on the contrary, the activity seems to be not related to the location of the samples.

  20. Keanakākoʻi Tephra produced by 300 years of explosive eruptions following collapse of Kīlauea's caldera in about 1500 CE

    Science.gov (United States)

    Swanson, Donald A.; Rose, Timothy R.; Fiske, Richard S.; McGeehin, John P.

    2012-01-01

    The Keanakākoʻi Tephra at Kīlauea Volcano has previously been interpreted by some as the product of a caldera-forming eruption in 1790 CE. Our study, however, finds stratigraphic and 14C evidence that the tephra instead results from numerous eruptions throughout a 300-year period between about 1500 and 1800. The stratigraphic evidence includes: (1) as many as six pure lithic ash beds interleaved in sand dunes made of earlier Keanakākoʻi vitric ash, (2) three lava flows from Kīlauea and Mauna Loa interbedded with the tephra, (3) buried syneruptive cultural structures, (4) numerous intraformational water-cut gullies, and (5) abundant organic layers rich in charcoal within the tephra section. Interpretation of 97 new accelerator mass spectrometry (AMS) 14C ages and 4 previous conventional ages suggests that explosive eruptions began in 1470–1510 CE, and that explosive activity continued episodically until the early 1800s, probably with two periods of quiescence lasting several decades. Kīlauea's caldera, rather than forming in 1790, predates the first eruption of the Keanakākoʻi and collapsed in 1470–1510, immediately following, and perhaps causing, the end of the 60-year-long, 4–6 km3 ʻAilāʻau eruption from the east side of Kīlauea's summit area. The caldera was several hundred meters deep when the Keanakākoʻi began erupting, consistent with oral tradition, and probably had a volume of 4–6 km3. The caldera formed by collapse, but no eruption of lava coincided with its formation. A large volume of magma may have quickly drained from the summit reservoir and intruded into the east rift zone, perhaps in response to a major south-flank slip event, leading to summit collapse. Alternatively, magma may have slowly drained from the reservoir during the prolonged ʻAilāʻau eruption, causing episodic collapses before the final, largest downdrop took place. Two prolonged periods of episodic explosive eruptions are known at Kīlauea, the Keanak

  1. Keanakākoʻi Tephra produced by 300 years of explosive eruptions following collapse of Kīlauea's caldera in about 1500 CE

    Science.gov (United States)

    Swanson, Donald A.; Rose, Timothy R.; Fiske, Richard S.; McGeehin, John P.

    2012-01-01

    The Keanakākoʻi Tephra at Kīlauea Volcano has previously been interpreted by some as the product of a caldera-forming eruption in 1790 CE. Our study, however, finds stratigraphic and 14C evidence that the tephra instead results from numerous eruptions throughout a 300-year period between about 1500 and 1800. The stratigraphic evidence includes: (1) as many as six pure lithic ash beds interleaved in sand dunes made of earlier Keanakākoʻi vitric ash, (2) three lava flows from Kīlauea and Mauna Loa interbedded with the tephra, (3) buried syneruptive cultural structures, (4) numerous intraformational water-cut gullies, and (5) abundant organic layers rich in charcoal within the tephra section. Interpretation of 97 new accelerator mass spectrometry (AMS) 14C ages and 4 previous conventional ages suggests that explosive eruptions began in 1470–1510 CE, and that explosive activity continued episodically until the early 1800s, probably with two periods of quiescence lasting several decades. Kīlauea's caldera, rather than forming in 1790, predates the first eruption of the Keanakākoʻi and collapsed in 1470–1510, immediately following, and perhaps causing, the end of the 60-year-long, 4–6 km3 ʻAilāʻau eruption from the east side of Kīlauea's summit area. The caldera was several hundred meters deep when the Keanakākoʻi began erupting, consistent with oral tradition, and probably had a volume of 4–6 km3. The caldera formed by collapse, but no eruption of lava coincided with its formation. A large volume of magma may have quickly drained from the summit reservoir and intruded into the east rift zone, perhaps in response to a major south-flank slip event, leading to summit collapse. Alternatively, magma may have slowly drained from the reservoir during the prolonged ʻAilāʻau eruption, causing episodic collapses before the final, largest downdrop took place. Two prolonged periods of episodic explosive eruptions are known at Kīlauea, the Keanak

  2. Estudio vulcanológico y qeoquímico del maar de la Caldera del Rey. Tenerife (Canarias

    Directory of Open Access Journals (Sweden)

    Paradas Herrero, A.

    1984-12-01

    Full Text Available In this study a cartographic, morphological, geochemical and petrographic study is made of the ''Caldera del Rey". The "Caldera del Rey" is a volcanic structure formed by two overlapping maars, The second one (maar that was formed is of greaten dimensions and destroyed part of the first one, Both maars erupted throught a possible fracture N 35 E, which is one of the directions with regional importance in the Archipelago. The eruption, which was very explosive, has been thought to be due in part to the great importance of the gaseous phase of the salic magma and also to the steam produced during the interaction of the magma with underground water. This explosivity can be clearly seen in the cleaf resalte cul out in the "Serie Basáltica Antigua" to some extent penetrated and fragmented by the eruption, The phreatomagmatic character of the eruption is evident because of the existence of accretionary lapilli. The materials emitted are exc1usively of aerial projection: agglomerates, tuffs cinerites. There was no flow of lava. ' Some of the fragments of tuffs as cinerites and pumice are comagmatic. These correspond to salic trachytic phonolitic rocks, which represent one of the last stages of differentiation of the alkaline oceanic magmas. The geochemical character of the materials of the "Caldera del Rey" is characteristic and can be easily distinguished from other nearly salic deposits formed in different cycles.

    En este trabajo se hace el estudio cartográfico, morfológico, petrográfico y geoquímico de la Caldera del Rey. La Caldera del Reyes un edificio volcánico formado por dos maars imbricados. El que se formó en segundo lugar es de mayores dimensiones y destruyó en parte el primero. Ambos aprovecharon para hacer erupción una posible fractura de dirección N 35'"E, de importancia regional en el Archipiélago. La erupción fue de una gran explosividad, que se supone debida, en parte, a la gran importancia de la fase gaseosa del

  3. Distribución espacial del Bosque Seco Tropical en el Valle del Cauca, Colombia

    Directory of Open Access Journals (Sweden)

    Diana Patricia Alvarado-Solano

    2015-09-01

    Full Text Available En el departamento del Valle del Cauca, la distribución de Bosque Seco Tropical (BsT se ha asociado al valle geográfico del río Cauca ubicado en la zona plana. Actualmente en esta zona, su cobertura se ha reducido a pocos relictos que se encuentran bajo alguna figura de conservación y mantienen áreas representativas de las formaciones vegetales sssstípicas de este bioma. Este trabajo se enfocó en el reconocimiento de la distribución espacial de formaciones vegetales de BsT en el departamento del Valle del Cauca. Se empleó información cartográfica secundaria para reconocer los biomas, ecosistemas y usos del suelo del área de estudio y en zonas adyacentes del piedemonte y montañas. Un modelo digital de elevaciones fue utilizado para realizar análisis altitudinales. En un sistema de información geográfico se aplicaron técnicas de geoprocesamiento y análisis geoespacial entre la información cartográfica y satelital. Los resultados evidencian que pese al avanzado deterioro de las coberturas de bosque seco en la zona plana, alrededor del 80 % se localiza en ecosistemas de montaña, específicamente en zonas de transición hacia bosques húmedos. A futuro, el potencial de estas áreas deberá evaluarse para ser incluidas en estrategias de conservación y restauración del bosque seco así como en el diseño de procesos adaptativos frente al cambio climático.

  4. Chemical data and variation diagrams of igneous rocks from the Timber Mountain-Oasis Valley Caldera Complex, southern Nevada

    Science.gov (United States)

    Quinlivan, W.D.; Byers, F.M.

    1977-01-01

    Silica variation diagrams presented here are based on 162 chemical analyses of tuffs, lavas, and intrusives, representative of volcanic centers of the Timber Mountain-Oasis Valley caldera complex and cogenetic rocks of the Silent Canyon ca1dera. Most of the volcanic units sampled are shown on the U.S. Geological Survey geologic map of the Timber Mountain caldera area (I-891) and are described in U.S. Geological Survey Professional Paper 919. Early effusives of the complex, although slightly altered, are probably chemically, and petrographically, more like the calc-alkalic Fraction Tuff (Miocene) of the northern Nellis Air Force Base Bombing and Gunnery Range to the north, whereas effusives of later Miocene age, such as the Paintbrush and Timber Mountain Tuffs, are alkali-calcic.

  5. FAUNA ANFIBIA DEL VALLE DE SIBUNDOY, PUTUMAYO-COLOMBIA

    Directory of Open Access Journals (Sweden)

    MUESES-CISNEROS JONH JAIRO

    2005-12-01

    Full Text Available La fauna Amphibia del Valle de Sibundoy consta de 32 especies agrupadas en dos órdenes, cinco familias y siete géneros. De éstas, cinco son especies nuevas cuya descripción se encuentra en proceso. Se amplía el límite altitudinal de otras siete y se presentan tres más para ser incluidas en la lista de anfibios de Colombia. A pesar de que en el lugar se han realizado colectas herpetológicas desde finales de los años sesenta, este estudio es el primero que se realiza en el Putumayo (uno de los departamentos menos muestreados del país.

  6. Magnetotelluric imaging of the resurgent caldera on the island of Ischia (southern Italy): inferences for its structure and activity

    Science.gov (United States)

    Di Giuseppe, M. G.; Troiano, A.; Carlino, S.

    2017-12-01

    The island of Ischia (located in the Bay of Naples, Italy) represents a peculiar case of a well-exposed caldera that has experienced a large (>800 m) and rapid resurgence, accompanied by volcanic activity. What drives the resurgence of calderas is a crucial issue to investigate, because this process is associated with potential eruptions and high risk to people living within and around such large active volcanic systems. To improve the knowledge of volcano-tectonic processes affecting the caldera of Ischia, electromagnetic imaging of the structures associated with its resurgence was performed and integrated with available geological information. A magnetotelluric (MT) survey of the island was carried out along two main profiles through the central-western sector, providing an electrical resistivity map to a depth of 3 km. These resistivity cross sections allowed us to identify the presence of a very shallow magmatic intrusion, possibly a laccolith, at a depth of about 1 km, which was responsible for both the resurgence and the volcanic activity. Furthermore, the tectonic structures bordering the resurgent area and the occurrence of a large thermal anomaly in the western sector of the caldera also provided a signature in the resistivity cross sections, with the magma intrusion producing advection of hot fluids with high geothermal gradients (>150 °C km-1) in the southern and western sectors. All of these data are fundamental for the assessment of the island's volcano-tectonic dynamics and their associated hazards. The structure and activity of the island have been controlled by the process of resurgence associated with the arrival of new magma and the progressive intrusion of a laccolith at a shallow depth. The reactivation of such a shallow system may imply imminent eruption which would pose a major volcanic hazard.

  7. Epidemiologia del parasitismo intestinal infantil en el Valle del Guadalquivir

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    Pérez Armengol Cristina

    1997-01-01

    Full Text Available FUNDAMENTO: Las parasitosis intestinales en los niños constituyen un problema de salud pública que debe ser valorado periódicamente en cada región. En este trabajo se aborda, por primera vez en la región natural del Valle del Guadalquivir, un estudio amplio sobre la prevalencia del parasitismo intestinal en la población infantil de la zona. MÉTODOS: Durante el período 1994-1996, mediante análisis coprológico y método de Graham, se ha estudiado a 1.917 niños y niñas asintomáticos, con edades comprendidas entre seis y diez años, residentes en veinte localidades del Valle del Guadalquivir. RESULTADOS: El índice global de parasitación ha sido del 27,12 %. Las especies parásitas detectadas, así como sus prevalencias fueron: Enterobius vermicularis (20,44%, Giardia lamblia (5,05%, Entamoeba coli (2,45%, Endolimax nana (1,61%, Entamoeba histolytica (0,31%, Entamoeba hartmanni (0,05%, Iodamoeba bütschlii (0,05%. CONCLUSIONES: La prevalencia global encontrada es similar a la de otras regiones españolas, aunque quizás pueda considerarse algo más favorable. No se detectan geohelmintos, debido posiblemente a la mejora de la infraestructura higiénico-sanitaria y a los efectos de la prolongada sequía en la zona. La giardiasis, a diferencia de las restantes protozoosis, mantiene una prevalencia relativamente alta.

  8. New geologic evidence for additional 16.5-15.5 Ma silicic calderas in northwest Nevada related to initial impingement of the Yellowstone hot spot

    International Nuclear Information System (INIS)

    Coble, Matthew A; Mahood, Gail A

    2008-01-01

    Three silicic calderas have been newly identified in northwest Nevada west of McDermitt caldera. This volcanism is interpreted to have formed during a short interval at 16.5-15.5 Ma, during the waning stage of Steens flood basalt volcanism after the initial impingement of the Yellowstone hot spot. New mapping demonstrates that the area affected by this mid-Miocene silicic volcanism is significantly larger than previously appreciated in the western U.S.

  9. New geologic evidence for additional 16.5-15.5 Ma silicic calderas in northwest Nevada related to initial impingement of the Yellowstone hot spot

    Energy Technology Data Exchange (ETDEWEB)

    Coble, Matthew A; Mahood, Gail A [Department Geological and Environmental Sciences, 450 Serra Mall, Bldg 320, Stanford University, Stanford, CA 94305-3115 (United States)

    2008-10-01

    Three silicic calderas have been newly identified in northwest Nevada west of McDermitt caldera. This volcanism is interpreted to have formed during a short interval at 16.5-15.5 Ma, during the waning stage of Steens flood basalt volcanism after the initial impingement of the Yellowstone hot spot. New mapping demonstrates that the area affected by this mid-Miocene silicic volcanism is significantly larger than previously appreciated in the western U.S.

  10. Levels of Heavy Metals in Adolescents Living in the Industrialised Area of Milazzo-Valle del Mela (Northern Sicily

    Directory of Open Access Journals (Sweden)

    Monica Interdonato

    2014-01-01

    Full Text Available In the Milazzo-Valle del Mela area, the presence of industrial plants and the oil refinery make local residents concerned for their health. For this reason, we evaluated the levels of heavy metals in 226 children aged 12–14 years, living in the 7 municipalities of the area. A control age-matched population (n=29 living 45 km far from the industrial site was also enrolled. Arsenic, cadmium, chromium, mercury, nickel, and vanadium were analysed in 24 h urine samples, while lead concentration was evaluated in blood samples. A questionnaire regarding life style and risk perception was also administered. Adolescents from Milazzo-Valle del Mela had cadmium levels significantly higher compared to either controls  (P<0.0001 or the reference values of the European Germany Environmental Survey (GerES-IV and the American National Health and Nutrition Examination Survey (NHANES. Furthermore, children had higher perception of living in a high-risk environment. The present data, for the first time, clearly indicate that adolescents living in Milazzo-Valle del Mela have increased body concentration of cadmium, which may be harmful to human health. These results deserve particular attention by the local and regional government to initiate prevention programmes in this susceptible population.

  11. Diagnóstico y propuesta para una gestión integral del riesgo en el Valle de Aburrá: red riesgos.

    OpenAIRE

    Aristizábal, Edier; Vargas, Richard; Mesa Sánchez, Óscar José

    2008-01-01

    A partir del análisis de la situación organizacional de las diferentes instituciones en el Valle de Aburrá frente a la reducción de desastres y emergencias asociadas con los fenómenos de origen natural y antrópico, el Área Metropolitana del Valle de Aburrá, como autoridad ambiental y entidad planificadora, hace una propuesta que pretende articular todas las entidades, organizaciones e instituciones públicas y privadas hacia una gestión integral del riesgo, y la cual denominó: Red para la Gest...

  12. Preliminary characterization of the Green Antioquian consumer: the case of the consumers from Valle de Aburra

    Directory of Open Access Journals (Sweden)

    Nelcy Rocío Escobar Moreno

    2015-07-01

    Full Text Available Rev.esc.adm.neg This research paper aims at identifying the profile of green consumers living in Valle de Aburra, in Antioquia, to identify the specific features and needs of this group as a market segment. At first, this article shows a conceptual framework about terms such as green market, green consumers and green products. Then, a research methodology is described based on a quantitative formulation of a piloting study, through which a measurement instrument having 14 questions divided into different variables product, price, distribution and communication collected key information to get to preliminary conclusions about consumers as its main object of study. Finally, a statistic descriptive analysis was made to get the profile of green consumers living in Valle de Aburra and a proposal describing key elements to set the bases for future investigations about this topic.

  13. Evidence for water influx from a caldera lake during the explosive hydromagmatic eruption of 1790, Kilauea volcano, Hawaii

    Science.gov (United States)

    Mastin, L.G.

    1997-01-01

    In 1790 a major hydromagmatic eruption at the summit of Kilauea volcano, Hawaii, deposited up to 10 m of pyroclastic fall and surge deposits and killed several dozen Hawaiian natives who were crossing the island. Previous studies have hypothesized that the explosivity of this eruption was due to the influx of groundwater into the conduit and mixing of the groundwater with ascending magma. This study proposes that surface water, not groundwater, was the agent responsible for the explosiveness of the eruption. That is, a lake or pond may have existed in the caldera in 1790 and explosions may have taken place when magma ascended into the lake from below. That assertion is based on two lines of evidence: (1) high vesicularity (averaging 73% of more than 3000 lapilli) and high vesicle number density (105-107 cm-3 melt) of pumice clasts suggest that some phases of the eruption involved vigorous, sustained magma ascent; and (2) numerical calculations suggest that under most circumstances, hydrostatic pressure would not be sufficient to drive water into the eruptive conduit during vigorous magma ascent unless the water table were above the ground surface. These results are supported by historical data on the rate of infilling of the caldera floor during the early 1800s. When extrapolated back to 1790, they suggest that the caldera floor was below the water table.

  14. Geologic field-trip guide to Long Valley Caldera, California

    Science.gov (United States)

    Hildreth, Wes; Fierstein, Judy

    2017-07-26

    This guide to the geology of Long Valley Caldera is presented in four parts: (1) An overview of the volcanic geology; (2) a chronological summary of the principal geologic events; (3) a road log with directions and descriptions for 38 field-trip stops; and (4) a summary of the geophysical unrest since 1978 and discussion of its causes. The sequence of stops is arranged as a four-day excursion for the quadrennial General Assembly of the International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI), centered in Portland, Oregon, in August 2017. Most stops, however, are written freestanding, with directions that allow each one to be visited independently, in any order selected.

  15. Metamorphic history of the Central Pyrenees Part II, Valle de Arán, Sheet 4

    NARCIS (Netherlands)

    Zwart, H.J.

    1963-01-01

    The structural geology and metamorphic petrology of the Bosost area in the Valle de Arán (Central Pyrenees) is discussed. The rocks exposed in this area consist of Cambro-Ordovician mica-schists with numerous granite and pegmatite bodies, phyllites and limestones; Silurian slates and schists and

  16. E/V Nautilus Detection of Isolated Features in the Eastern Pacific Ocean: Newly Discovered Calderas and Methane Seeps

    Science.gov (United States)

    Raineault, N.; Irish, O.; Lubetkin, M.

    2016-02-01

    The E/V Nautilus mapped over 80,000 km2 of the seafloor in the Gulf of Mexico and Eastern Pacific Ocean during its 2015 expedition. The Nautilus used its Kongsberg EM302 multibeam system to map the seafloor prior to remotely operated vehicle (ROV) dives, both for scientific purposes (site selection) and navigational safety. The Nautilus also routinely maps during transits to identify previously un-mapped or unresolved seafloor features. During its transit from the Galapagos Islands to the California Borderland, the Nautilus mapped 44,695 km2 of seafloor. Isolated features on the seafloor and in the water-column, such as calderas and methane seeps, were detected during this data collection effort. Operating at a frequency of 30 kHz in waters ranging from 1000-5500 m, we discovered caldera features off the coast of Central America. Since seamounts are known hotspots of biodiversity, locating new ones may enrich our understanding of seamounts as "stepping stones" for species distribution and ocean current pathways. Satellite altimetry datasets prior to this data either did not discern these calderas or recognized the presence of a bathymetric high without great detail. This new multibeam bathymetry data, gridded at 50 m, gives a precise look at these seamounts that range in elevation from 350 to 1400 m from abyssal depth. The largest of the calderas is circular in shape and is 10,000 m in length and 5,000 m in width, with a distinct circular depression at the center of its highest point, 1,400 m above the surrounding abyssal depth. In the California Borderland region, located between San Diego and Los Angeles, four new seeps were discovered in water depths from 400-1,020 m. ROV exploration of these seeps revealed vent communities. Altogether, these discoveries reinforce how little we know about the global ocean, indicate the presence of isolated deep-sea ecosystems that support biologically diverse communities, and will impact our understanding of seafloor habitat.

  17. Time-to-event analysis of mastitis at first-lactation in Valle del Belice ewes

    NARCIS (Netherlands)

    Portolano, B.; Firlocchiaro, R.; Kaam, van J.B.C.H.M.; Riggio, V.; Maizon, D.O.

    2007-01-01

    A time-to-event study for mastitis at first-lactation in Valle del Belice ewes was conducted, using survival analysis with an animal model. The goals were to evaluate the effect of lambing season and level of milk production on the time from lambing to the day when a ewe experienced a test-day with

  18. Rapid differentiation in a sill-like magma reservoir: a case study from the campi flegrei caldera.

    Science.gov (United States)

    Pappalardo, Lucia; Mastrolorenzo, Giuseppe

    2012-01-01

    In recent decades, geophysical investigations have detected wide magma reservoirs beneath quiescent calderas. However, the discovery of partially melted horizons inside the crust is not sufficient to put constraints on capability of reservoirs to supply cataclysmic eruptions, which strictly depends on the chemical-physical properties of magmas (composition, viscosity, gas content etc.), and thus on their differentiation histories. In this study, by using geochemical, isotopic and textural records of rocks erupted from the high-risk Campi Flegrei caldera, we show that the alkaline magmas have evolved toward a critical state of explosive behaviour over a time span shorter than the repose time of most volcanic systems and that these magmas have risen rapidly toward the surface. Moreover, similar results on the depth and timescale of magma storage were previously obtained for the neighbouring Somma-Vesuvius volcano. This consistency suggests that there might be a unique long-lived magma pool beneath the whole Neapolitan area.

  19. VALORIZACIÓN DE RESIDUOS AGROINDUSTRIALES - FRUTAS - EN MEDELLÍN Y EL SUR DEL VALLE DEL ABURRÁ, COLOMBIA AGROINDUSTRIAL WASTE VALORIZATION - FRUITS - IN MEDELLÍN AND THE SOUTH OF VALLE DE ABURRÁ, COLOMBIA

    Directory of Open Access Journals (Sweden)

    Sandra Milena Yepes

    2008-06-01

    Full Text Available Los residuos industriales siguen convirtiéndose en un gran problema no sólo ambiental sino económico, ya que las mismas empresas tienen que asumir altos costos de disposición de éstos. Tal es el caso de la gran cantidad de residuos de frutas que se producen en la ciudad de Medellín y sus alrededores, debido al número extenso de empresas de este sector agroindustrial. En el presente trabajo se realizó un sondeo en Medellín y el Sur del Valle del Aburrá para conocer la problemática actual de estos residuos. Posteriormente se realizó una caracterización físico-química a los residuos más representativos que permitiera proponer diferentes alternativas de aprovechamiento. Los principales residuos de las empresas encuestadas provienen de naranja, guayaba, guanábana y mango. Los principales procesos de valorización incluyen el compostaje, la lombricultura y la obtención de productos químicos. Sólo con las empresas encuestadas podrían montarse plantas de valorización de residuos con capacidad de procesamiento de 9 a 375 ton/mes, dependiendo del proceso. Si se utilizaran todos los residuos generados en Medellín y el Sur del Valle del Aburrá, la capacidad de estas plantas de valorización podrían multiplicarse por 20.Industrial residues continuing being and economic problem so companies have to assume high costs to manage them. Such is the case of large amounts of fruit residues produced in Medellín, city and surroundings due to a great number of companies of this agroindustrial sector. In this work a scan was made in Medellín and the South of Valle de Aburrá to know the current problem of these residues. Subsequently a physical-chemistry characterization of the most representative residues with the purpose to propose different alternative uses. The main residues of the interviewed companies come from orange, guava, guanabana and mango. The main valorization processes include compost, worms culture and obtaining chemical

  20. Survey and assessment of post volcanic activities of a young caldera lake, Lake Cuicocha, Ecuador

    Directory of Open Access Journals (Sweden)

    G. Gunkel

    2009-05-01

    Full Text Available Cuicocha is a young volcano adjacent to the inactive Pleistocene Cotacachi volcano complex, located in the western cordilleras of the Ecuadorian Andes. A series of eruptions with intensive ash emission and collapse of the caldera occurred around 4500–3000 y BP. A crater 3.2 km in diameter and a maximum depth of 450 m was formed. Further eruptions of the volcano occurred 1300 y BP and formed four smaller domes within the caldera. Over the last few hundred years, a caldera lake has developed, with a maximum depth of 148 m. The lake water is characterized by sodium carbonate with elevated concentrations of manganese, calcium and chloride. Nowadays, an emission of gases, mainly CO2, and an input of warm spring water occur in Lake Cuicocha. The zone of high activity is in the western basin of the lake at a depth of 78 m, and continuous gas emissions with sediment resuspension were observed using sonar. In the hypolimnion of the lake, CO2 accumulation occurs up to 0.2% saturation, but the risk of a limnic eruption can be excluded at present. The lake possesses monomictic stratification behaviour, and during overturn an intensive gas exchange with the atmosphere occurs. Investigations concerning the sedimentation processes of the lake suggest only a thin sediment layer of up to 10–20 cm in the deeper lake basin; in the western bay, in the area of gas emissions, the lake bottom is partly depleted of sediment in the form of holes, and no lake colmation exists. Decreases in the lake water level of about 30 cm y−1 indicate a percolation of water into fractures and fissures of the volcano, triggered by a nearby earthquake in 1987.

  1. Manejo de Mercancías Químicas peligrosas en puerto Caldera, Puntarenas, Costa Rica.

    Directory of Open Access Journals (Sweden)

    José Carlos Mora

    2016-03-01

    Full Text Available Puerto Caldera, located in Puntarenas, Costa Rica, is one of the most important Harbors of Central America, which is a key point to transport about 1.5 millions of metric tons of different categories of products every year, including dangerous chemical merchandise. The chemical has have originated emergencies, which has given rise to the necessity to asses load and unload process, and storage. In attention to the matter the most important aspects related to the fulfillment of the national and international norms during the merchandise dangerous transportation in Harbors were evaluated. According to the evaluation of the different handling, storage and transportation processes, Puerto Caldera, face among others the following problems: Personal training necessities addressed to the employees involved in the process of handling dangerous merchandise. Insufficient equipment and materials to guarantee a safe environment. The permanence of merchandise for long periods in warehouse. Unsuitable conditions of warehouse for the proper storage of chemical merchandise. Absence of classification and location criteria of dangerous chemical merchandise in the unloading and loading areas as well as in warehouse. Based up the previous evaluations, the following aspects were developed: An improvement plan for adequate handling of chemical merchandise. Recommendation of specific guidelines to create a Contingencies Plan. The purposes of the two aspects are to promote actions to diminish the risk of accidents associated to the handling of a dangerous merchandise. In the same way, it was proposed a Plan of Improvement and basic lineaments to elaborate a Plan of Contingencies that includes actions to diminish the risk of accidents associated to the handling of dangerous merchandise and to diminish the consequences, in case of accident, as far as the loss of lives, damages to the people, the property and the environment. All this will make Puerto Caldera a safe place

  2. Stress evolution during caldera collapse

    Science.gov (United States)

    Holohan, E. P.; Schöpfer, M. P. J.; Walsh, J. J.

    2015-07-01

    The mechanics of caldera collapse are subject of long-running debate. Particular uncertainties concern how stresses around a magma reservoir relate to fracturing as the reservoir roof collapses, and how roof collapse in turn impacts upon the reservoir. We used two-dimensional Distinct Element Method models to characterise the evolution of stress around a depleting sub-surface magma body during gravity-driven collapse of its roof. These models illustrate how principal stress orientations rotate during progressive deformation so that roof fracturing transitions from initial reverse faulting to later normal faulting. They also reveal four end-member stress paths to fracture, each corresponding to a particular location within the roof. Analysis of these paths indicates that fractures associated with ultimate roof failure initiate in compression (i.e. as shear fractures). We also report on how mechanical and geometric conditions in the roof affect pre-failure unloading and post-failure reloading of the reservoir. In particular, the models show how residual friction within a failed roof could, without friction reduction mechanisms or fluid-derived counter-effects, inhibit a return to a lithostatically equilibrated pressure in the magma reservoir. Many of these findings should be transferable to other gravity-driven collapse processes, such as sinkhole formation, mine collapse and subsidence above hydrocarbon reservoirs.

  3. Pyroclastic eruptions from Axial caldera, Juan de Fuca Ridge, NE Pacific Ocean

    Energy Technology Data Exchange (ETDEWEB)

    Helo, Christoph; Stix, John [Department of Earth and Planetary Sciences, McGill University, 3450 University Street, Montreal, Quebec H3A 2A7 (Canada); Clague, Dave A [Monterey Bay Aquarium Research Institute 7700 Sandholdt Road, Moss Landing, CA 95039-9644 (United States)

    2008-10-01

    Unconsolidated volcaniclastic glass deposits on the flanks of Axial Seamount, a caldera system situated on the Juan de Fuca Ridge in the NE Pacific Ocean, demonstrate the occurrence of explosive events, in addition to effusive activity. The variety of produced glass fragments ranges from various angular forms to thin deep-sea limu o Pele, with dominantly moderately fractionated to occasionally primitive MOR basalt composition. A model involving the collapse of a magmatic foam layer may account for the observed spectrum of glass fragments.

  4. Données récentes de l'épidémiologie de la fièvre de la Vallée du Rift (F.V.R.) au Sénégal

    OpenAIRE

    Thiongane, Y.; Thonnon, J.; Zeller, H.; Lo, M. M.; Faty, A.; Diagne, F.; Gonzalez, J.; Akakpo, J. A.; Fontenille, Didier; Digoutte, J. P.

    1998-01-01

    La fièvre de la Vallée du Rift est une anthropozoonose largement répandue en Afrique. En 1987, s'est déclarée une épidémie très meurtrière de la fièvre de la Vallée du Rift (FVR) dans la Basse Vallée du Fleuve Sénégal. En raison du risque de réactivation, un programme de surveillance sérologique a été mis en place dans des zones sahéliennes cibles : vallées du Sénégal et Ferlo. Des troupeaux de ruminants domestiques (bovins, ovins et caprins) ont été régulièrement surveillés et testés. Les sé...

  5. Primer registro de Phyllodactylus sentosus (Squamata: Phyllodactylidae) para el valle del río Chillón, Lima, Perú

    OpenAIRE

    Diego Olivera; Luis Castillo; Gerardo Gutiérrez

    2016-01-01

    El gecko de Lima Phyllodactylus sentosus (Dixon & Huey, 1970) identificado como en peligro crítico de extinción ha sido registrado sólo en algunas localidades entre los valles de los ríos Rímac y Lurín, en el centro y sur de la ciudad de Lima, Región Lima, sin embargo, su distribución hacia el norte no está documentada. En el presente trabajo se reporta por primera vez la presencia de P. sentosus en la Huaca Tambo Inga, ubicada en el margen derecho del valle del río Chillón en el distrito de ...

  6. Application of low-enthalpy geothermal energy in the New Hospital of Mollet del Valles; Aplicacion de la geotermia de baja entalpia en el nuevo Hospital de Mollet del Valles

    Energy Technology Data Exchange (ETDEWEB)

    Cuesta Garcia, M. A.; Mayoral Fernandez, G. R.

    2009-07-01

    The new Hospital in the city of Mollet del Valles has chosen Geothermic energy for heating and cooling. The installation, built between year 2007 to 2009, will turn the hospital into one of the most sustainable building of Spain because will supply more than 1 MW of heating and cooling peak load with Goethermic energy. Now, this project is the biggest in Spain and it is one of the five biggest in all Europe. (Author)

  7. La Pachahuara de Acolla: una danza de los esclavos negros en el valle de Yanamarca

    Directory of Open Access Journals (Sweden)

    1976-01-01

    Full Text Available La danse 'Pachahuara' se pratique pendant la Noël dans la vallée du rio Mantaro (Pérou central et son origine remonte à l'arrivée d'esclaves noirs dans la sierra péruvienne (Jauja, 1533. La danse décrite est celle de la communauté d'Acolla (N de Huancayo}. Une description des costumes des différents personnages est donnée avant de passer à la chorégraphie proprement dite. Deux phases caractérisent le pachahuara, avec une musique bien différenciée. Une tentative d'interprétation suit la description, s'appuyant sur des données historiques concernant l'établissement d'esclaves noirs dans la vallée du Mantaro la danse symboliserait l'esclavitude puis la liberté retrouvée. El baile 'Pachahuara' se practica durante la Navidad en el valle del río Mantaro (Perú Central y su origen se remonta a la llegada de esclavos negros en la sierra peruana (Jauja, 1533. La danza descrita es la de la comunidad de Acolla (N de Huancayo. Una descripción de los trajes de los distintos personajes ha sido dada antes de pasar a la coreografía propiamente dicha. Dos fases caracterizan la pachahuara, con una música bien diferenciada. Una tentativa de interpretación sigue a la descripción, basándose en datos históricos referentes al establecimiento de esclavos negros en el valle del Mantaro la danza simbolizaría la esclavitud y después la libertad recuperada. The dance 'Pachahuara' is practiced during the Christmas times in the valley of the Rio Mantaro (Central Peru and its origin dates back to the coming of the black slaves in the peruvian sierra (Jauja, 1533. The dance described is that of the Acolla community (North of Huancayo. A description of the different personnages'clothes is given before analyzing the choreography itself. Two phases characterize the pachahuara, with a well differenced music. An attempt of interpretation is following the description, basing it upon historical referring concerning the establishment of the black slaves

  8. The earliest low and high δ18O caldera-forming eruptions of the Yellowstone plume: Implications for the 30–40 Ma Oregon calderas and speculations on plume-triggered delaminations

    Directory of Open Access Journals (Sweden)

    Angela Nicole Seligman

    2014-11-01

    Full Text Available We present new isotopic and trace element data for four eruptive centers in Oregon: Wildcat Mountain (40 Ma, Crooked River (32–28 Ma, Tower Mountain (32 Ma, and Mohawk River (32 Ma. The first three calderas are located too far east to be sourced through renewed subduction of the Farallon slab following accretion of the Yellowstone-produced Siletzia terrane at ~50 Ma. Basalts of the three eastern eruptive centers yield high Nb/Yb and Th/Yb ratios, indicating an enriched sublithospheric mantle source, while Mohawk River yields trace element and isotopic (δ18O and εHf values that correlate with its location above a subduction zone. The voluminous rhyolitic tuffs and lavas of Crooked River (41 x 27 km have δ18Ozircon values that include seven low δ18Ozircon units (1.8–4.5 ‰, one high δ18Ozircon unit (7.4–8.8 ‰, and two units with heterogeneous zircons (2.0–9.0 ‰, similar to younger Yellowstone-Snake River Plain rhyolites. In order to produce these low δ18O values, a large heat source, widespread hydrothermal circulation, and repeated remelting are all required. In contrast, Wildcat Mountain and Tower Mountain rocks yield high δ18Ozircon values (6.4–7.9 ‰ and normal to low εHfi values (5.2–12.6, indicating crustal melting of high-δ18O supracrustal rocks. We propose that these calderas were produced by the first appearance of the Yellowstone plume east of the Cascadia subduction zone, which is supported by plate reconstructions that put the Yellowstone plume under Crooked River at 32–28 Ma. Given the eastern location of these calderas along the suture of the accreted Siletzia terrane and North America, we suggest that the Yellowstone hotspot is directly responsible for magmatism at Crooked River, and for plume-assisted delamination of portions of the edge of the Blue Mountains that produced the Tower Mountain magmas, while the older Wildcat Mountain magmas are related to suture zone instabilities that were created

  9. Una mirada a la situación de la niñez en el Valle del Cauca

    Directory of Open Access Journals (Sweden)

    Ana María Osorio

    2010-10-01

    Full Text Available En este documento identificamos un conjunto de indicadores a nivel departamental y municipal (en la medida en que la información lo permite con perspectiva de niñez, indicadores que facilitan analizar el bienestar y cumplimiento de los derechos de los niños y niñas en distintas áreas: salud, educación, alimentación, vivienda digna, y la exposición a riesgos tempranos como el trabajo y la maternidad. La construcción de indicadores a nivel municipal que reflejan el bienestar y/o el cumplimiento de los derechos, ofrece una oportunidad para obtener una imagen completa de la situación de la niñez en un departamento, y constituye una herramienta sumamente importante en el diseño de la política pública y la focalización del gasto. Los indicadores del Valle del Cauca aquí presentados reflejan inequidades geográficas en la provisión y acceso de servicios sociales básicos; en ellos se evidencian grandes brechas entre municipios frente al promedio departamental y la ciudad de Cali. Los mayores rezagos se concentran en algunos municipios del norte del Valle y el municipio de Buenaventura. Todo esto plantea importantes retos de política pública, e invitan al debate, al análisis y a la visualización de las condiciones de vida de la niñez en el Valle del Cauca.

  10. Una mirada a la situación de la niñez en el Valle del Cauca

    Directory of Open Access Journals (Sweden)

    Ana María Osorio

    2010-01-01

    Full Text Available En este documento identificamos un conjunto de indicadores a nivel departamental y municipal (en la medida en que la información lo permite con perspectiva de niñez, indicadores que facilitan analizar el bienestar y cumplimiento de los derechos de los niños y niñas en distintas áreas: salud, educación, alimentación, vivienda digna, y la exposición a riesgos tempranos como el trabajo y la maternidad. La construcción de indicadores a nivel municipal que reflejan el bienestar y/o el cumplimiento de los derechos, ofrece una oportunidad para obtener una imagen completa de la situación de la niñez en un departamento, y constituye una herramienta sumamente importante en el diseño de la política pública y la focalización del gasto. Los indicadores del Valle del Cauca aquí presentados reflejan inequidades geográficas en la provisión y acceso de servicios sociales básicos; en ellos se evidencian grandes brechas entre municipios frente al promedio departamental y la ciudad de Cali. Los mayores rezagos se concentran en algunos municipios del norte del Valle y el municipio de Buenaventura. Todo esto plantea importantes retos de política pública, e invitan al debate, al análisis y a la visualización de las condiciones de vida de la niñez en el Valle del Cauca.

  11. Zeolites of the Valle Central of Costa Rica and its outskirts

    International Nuclear Information System (INIS)

    Zeledon, Luis Alonso

    2004-01-01

    19 different species of zeolites have been found in 25 outcrops in the Valle Central of Costa Rica and in the Siquirres region. All the zeolites are secondary minerals and crystallized in little veins and vesicles of the basalts and pyroclastics rocks of the La Cruz and Grifo Alto formations, belonging to the Aguacate Group and the alkaline igneous rocks of Guayacan. The most frequent species of zeolites are stibnite, chabasite, laumontite, mesolite/mordenite, thomsonite, and analcime. Natrolite only was found near to Siquirres. (Author) [es

  12. "Estudio prospectivo de hatos ganaderos, del valle de Ubate, condiciones actuales, limitantes y necesidades de desarrollo para entrar a competir en el mercado internacional"

    OpenAIRE

    Prieto, Juan Antonio; Uribe Aguado, Manuela; Valdivieso Ruiz, Maria Camila

    2011-01-01

    El siguiente trabajo titulado “Estudio Prospectivo de hatos ganaderos, del Valle de Ubate, Condiciones Actuales, Limitantes y Necesidades de Desarrollo Para entrar a Competir en el Mercado Internacional” encontrara un ejercicio prospectivo orientado a establecer posibles escenarios futuros para los ganaderos, productores de leche del Valle de Ubate, a entrar nuevos mercados como el europeo y americano al mercado Colombiano, así mismo propone un análisis de las variables relevantes de las co...

  13. ZONAS FRÍAS EN EL VALLE DEL RÍO NEUQUÉN: SU DETECCIÓN MEDIANTE IMÁGENES NOAA-AVHRR

    Directory of Open Access Journals (Sweden)

    Marisa Cogliati

    2003-12-01

    Full Text Available El valle inferior del río Neuquén se encuentra incluido en la zona agrícola conocida como Alto Valle del río Negro (AVRN que a pesar de su denominación, incluye además los valles inferiores de los ríos Limay y Neuquén. En esta región se destaca una intensa actividad frutihortícola. Las heladas tardías (que ocurren en los meses de setiembre y octubre constituyen riesgos importantes para dicha actividad llegando incluso a ocasionar grandes pérdidas económicas. Debido a ello, en los valles, se invierten grandes sumas de dinero en la lucha contra las heladas. El Alto Valle del Río Negro es una región con características propias, por los recursos del suelo y subsuelo, por el avance de las ciudades, el numero de habitantes y la tecnificación. La zona cultivada ocupa terrazas fluviales y el abastecimiento de agua se realiza por medio del riego artificial. La superficie regada es de 100000 has. El estudio de las características del clima de la región así como de cada una de las variables climáticas tiene implicancias que poco a poco han sido consideradas por los diferentes agentes del sector productivo. Esto se ve reflejado en la cantidad de estaciones meteorológicas automáticas que han sido adquiridas en la región, tanto por el sector privado como por los organismos públicos relacionados al sector productivo fruti-hortícola (INTA, FUNBAPA; UNC, etc.. Desde hace unos años, se han efectuado distintos esfuerzos aislados desde todas esas instituciones para reunir información y analizar las características propias de la región, sin que se hayan coordinado esfuerzos. Los estudios realizados presentan en su mayoría el estudio de datos de las estaciones meteorológicas convencionales pertenecientes al Servicio Meteorológico Nacional y a la Facultad de Ciencias Agrarias de la Universidad Nacional del Comahue con registros de aproximadamente 30 años, pero no presentan un estudio espacial del tema, sino que definen ciertas

  14. The timing and origin of pre- and post-caldera volcanism associated with the Mesa Falls Tuff, Yellowstone Plateau volcanic field

    Science.gov (United States)

    Stelten, Mark E.; Champion, Duane E.; Kuntz, Mel A.

    2018-01-01

    We present new sanidine 40Ar/39Ar ages and paleomagnetic data for pre- and post-caldera rhyolites from the second volcanic cycle of the Yellowstone Plateau volcanic field, which culminated in the caldera-forming eruption of the Mesa Falls Tuff at ca. 1.3 Ma. These data allow for a detailed reconstruction of the eruptive history of the second volcanic cycle and provide new insights into the petrogenesis of rhyolite domes and flows erupted during this time period. 40Ar/39Ar age data for the biotite-bearing Bishop Mountain flow demonstrate that it erupted approximately 150 kyr prior to the Mesa Falls Tuff. Integrating 40Ar/39Ar ages and paleomagnetic data for the post-caldera Island Park rhyolite domes suggests that these five crystal-rich rhyolites erupted over a centuries-long time interval at 1.2905 ± 0.0020 Ma (2σ). The biotite-bearing Moonshine Mountain rhyolite dome was originally thought to be the downfaulted vent dome for the pre-caldera Bishop Mountain flow due to their similar petrographic and oxygen isotope characteristics, but new 40Ar/39Ar dating suggest that it erupted near contemporaneously with the Island Park rhyolite domes at 1.2931 ± 0.0018 Ma (2σ) and is a post-caldera eruption. Despite their similar eruption ages, the Island Park rhyolite domes and the Moonshine Mountain dome are chemically and petrographically distinct and are not derived from the same source. Integrating these new data with field relations and existing geochemical data, we present a petrogenetic model for the formation of the post-Mesa Falls Tuff rhyolites. Renewed influx of basaltic and/or silicic recharge magma into the crust at 1.2905 ± 0.0020 Ma led to [1] the formation of the Island Park rhyolite domes from the source region that earlier produced the Mesa Falls Tuff and [2] the formation of Moonshine Mountain dome from the source region that earlier produced the biotite-bearing Bishop Mountain flow. These magmas were stored in the crust for less than a few thousand

  15. FEM-based linear inverse modeling using a 3D source array to image magma chambers with free geometry. Application to InSAR data from Rabaul Caldera (PNG).

    Science.gov (United States)

    Ronchin, Erika; Masterlark, Timothy; Dawson, John; Saunders, Steve; Martí Molist, Joan

    2015-04-01

    In this study, we present a method to fully integrate a family of finite element models (FEMs) into the regularized linear inversion of InSAR data collected at Rabaul caldera (PNG) between February 2007 and December 2010. During this period the caldera experienced a long-term steady subsidence that characterized surface movement both inside the caldera and outside, on its western side. The inversion is based on an array of FEM sources in the sense that the Green's function matrix is a library of forward numerical displacement solutions generated by the sources of an array common to all FEMs. Each entry of the library is the LOS surface displacement generated by injecting a unity mass of fluid, of known density and bulk modulus, into a different source cavity of the array for each FEM. By using FEMs, we are taking advantage of their capability of including topography and heterogeneous distribution of elastic material properties. All FEMs of the family share the same mesh in which only one source is activated at the time by removing the corresponding elements and applying the unity fluid flux. The domain therefore only needs to be discretized once. This precludes remeshing for each activated source, thus reducing computational requirements, often a downside of FEM-based inversions. Without imposing an a-priori source, the method allows us to identify, from a least-squares standpoint, a complex distribution of fluid flux (or change in pressure) with a 3D free geometry within the source array, as dictated by the data. The results of applying the proposed inversion to Rabaul InSAR data show a shallow magmatic system under the caldera made of two interconnected lobes located at the two opposite sides of the caldera. These lobes could be consistent with feeding reservoirs of the ongoing Tavuvur volcano eruption of andesitic products, on the eastern side, and of the past Vulcan volcano eruptions of more evolved materials, on the western side. The interconnection and

  16. Post-glacial inflation-deflation cycles, tilting, and faulting in the Yellowstone Caldera based on Yellowstone Lake shorelines

    Science.gov (United States)

    Pierce, Kenneth L.; Cannon, Kenneth P.; Meyer, Grant A.; Trebesch, Matthew J.; Watts, Raymond D.

    2002-01-01

    The Yellowstone caldera, like many other later Quaternary calderas of the world, exhibits dramatic unrest. Between 1923 and 1985, the center of the Yellowstone caldera rose nearly one meter along an axis between its two resurgent domes (Pelton and Smith, 1979, Dzurisin and Yamashita, 1987). From 1985 until 1995-6, it subsided at about two cm/yr (Dzurisin and others, 1990). More recent radar interferometry studies show renewed inflation of the northeastern resurgent dome between 1995 and 1996; this inflation migrated to the southwestern resurgent dome from 1996 to 1997 (Wicks and others, 1998). We extend this record back in time using dated geomorphic evidence of postglacial Yellowstone Lake shorelines around the northern shore, and Yellowstone River levels in the outlet area. We date these shorelines using carbon isotopic and archeological methods. Following Meyer and Locke (1986) and Locke and Meyer (1994), we identify the modern shoreline as S1 (1.9 ? 0.3 m above the lake gage datum), map paleoshoreline terraces S2 to S6, and infer that the prominent shorelines were cut during intracaldera uplift episodes that produced rising water levels. Doming along the caldera axis reduces the gradient of the Yellowstone River from Le Hardys Rapids to the Yellowstone Lake outlet and ultimately causes an increase in lake level. The 1923-1985 doming is part of a longer uplift episode that has reduced the Yellowstone River gradient to a ?pool? with a drop of only 0.25 m over most of this 5 km reach. We also present new evidence that doming has caused submergence of some Holocene lake and river levels. Shoreline S5 is about 14 m above datum and estimated to be ~12.6 ka, because it post-dates a large hydrothermal explosion deposit from the Mary Bay area (MB-II) that occurred ~13 ka. S4 formed about 8 m above datum ~10.7 ka as dated by archeology and 14C, and was accompanied by offset on the Fishing Bridge fault. About 9.7 ka, the Yellowstone River eroded the ?S-meander?, followed

  17. RASGOS GEOGRÁFICOS DEL VALLE DEL RIO AGRIO INFERIOR.

    Directory of Open Access Journals (Sweden)

    Celia Torren

    1993-12-01

    Full Text Available El presente artículo es una síntesis del trabajo "Rasgos Geográficos del Valle del Río Agrio Inferior, el cual es un estudio de base para el conocimiento de la geografía de la región: - apoyando el esfuerzo que está realizando la población del área para lograr una identidad propia y una definitiva integración al contexto provincial; - aportando al proyecto "Rescate Arqueológico en Quili Malal, Neuquén" (subsidiado por CONICET y UNESCO, cuya dirección está a cargo de la profesora Susana Rodríguez de la U.N.C., a través de la confección del mapa geomorfológico del área; y - contribuyendo a los estudios que resultan necesarios ante la construcción de una obra hidroeléctrica de la magnitud de "El Chihuido I", emprendimiento que será llevado a cabo por Agua y Energía eléctrica de la Nación. Los límites del área estudiada fueron establecidos teniendo en cuenta el área del valle inferior del Río Agrio que será completamente inundada por el futuro embalse de la represa "El Chihuido I", a emplazarse 5,5 Km aguas abajo de la confluencia de los ríos Agrio y Neuquén. Además de esta área de afectación directa se tomó también una zona de perilago estrechamente vinculada a la anterior. De esta manera los límites este y oeste quedaron establecidos por la confluencia de los ríos antes mencionados y la localidad de Bajada del Agrio, respectivamente.

  18. Le Paléolithique de la Vallée de l'Arros.

    Directory of Open Access Journals (Sweden)

    Jean Barrage

    1993-01-01

    Full Text Available Entre los ríos Adour y Neste, en los Pirineos centrales, el valle medio y superior del río Arros fue ocupado episódicamente por los hombres prehistóricos : En el Paleolítico Inferior con un Achelense sobre cuarcita, en el Paleolítico Medio con estaciones Mustenienses en los altos de las colinas y Magdaleniense clásico en las cuevas de Lomné y Espêche.

  19. Balance hidrológico en los valles de Tambo, Moquegua e Ilo

    OpenAIRE

    Instituto Nacional de Desarrollo

    2001-01-01

    Realiza el Balance hidrológico en los valles de Tambo, Moquegua e Ilo a fin de conocer la problemática del recurso hídrico en la dicha zona ante la posibilidad de otorgar derechos de uso de agua para el desarrollo de un proyecto minero y contar con un documento técnico que permita analizar, evaluar y proponer alternativas de solución a posibles conflictos en torno al aprovechamiento del agua.

  20. Mito, historia e identidad en Cachi (Valles Calchaquíes, Salta

    Directory of Open Access Journals (Sweden)

    Paula Lanusse

    2010-07-01

    Full Text Available El artículo trata acerca de la memoria de los antiguos en una localidad del sudoeste de la provincia de Salta (Cachi, región de los Valles Calchaquíes. En esta área la población aborigen fue sometida en el siglo diecisiete, iniciándose luego un proceso ambivalente de invisibilización étnica y persistencia de marcaciones indígenas en la definición de la singularidad de sujetos subalternos. A partir del análisis de relatos orales y de prácticas espaciales de estos sujetos cacheños, se busca interpretar el modo y el significado en que construyen una memoria de los antiguos, enfatizando las ideas de tiempo y espacio implicadas en esas historias y reflexionando acerca del correlato identitario que presuponen.This article is about memory of los antiguos (the ancients ones in a southwestern locale of Salta (Valles Calchaquíes, Salta, Argentina. In this area the aboriginal people was subdued during the 17th century following an ambivalent process of ethnic invisibilization and persistent use of ethnic markers to define the subaltern population up to the present. By analyzing Cachi subalterns' oral narratives and spatial practices I attempt to interpret the modes in which they construe a memory of los antiguos, paying attention to the notions of space and time contained therein and the identity correlate they presuppose.

  1. Developments of ozone generation using dielectric barrier discharge at the Universidad del Valle

    OpenAIRE

    Echeverry-Ibarra, Diego F.

    2013-01-01

    This paper presents the research results related to ozone technology using dielectric barrier discharge DBD, obtained at the Universidad del Valle. Particular emphasis is placed on increasing efficiency, the modeling of the surface dielectric barrier discharge generator and the control technique which modifies the relation production vs. efficiency of the generators. Finally, the ozone applications worked at the university are presented. The current state of these developments is promising fo...

  2. Posoqoypata, un cementerio Wari en el valle de Ayacucho, Perú

    OpenAIRE

    Valdez, Lidio M.; Valdez, J. Ernesto; Bettcher, Katrina J.

    2015-01-01

    Recientemente efectuamos un trabajo de rescate arqueológico en un cementerio Wari en el valle de Ayacucho. Dicho trabajo permitió el descubrimiento de formas mortuarias totalmente novedosas para la región y para la cultura Wari en particular. La primera consiste en una cámara funeraria de forma rectangular, con un acceso orientado hacia el lado este, y que contenía los restos de varios individuos. La segunda tiene la forma de una pequeña cista de forma cilíndrica que contenía los restos de un...

  3. Política pública de la migración en el Departamento del Valle del Cauca. ¿Cómo se está tratando el tema de la migración internacional, en el Departamento del Valle del Cauca hasta el 2009?

    Directory of Open Access Journals (Sweden)

    Lorena López López

    2011-08-01

    Full Text Available El presente documento de trabajo se basa en la tesis de grado, presentada en la Universidad Icesi de Cali, bajo el mismo título del presente artículo. El texto aborda la Política Integral Migratoria (PIM de Colombia y sus implicaciones en el departamento del Valle del Cauca. El documento está dividido en cuatro temas principales. Primero, se presenta el marco teórico, enfocado, particularmente, en el concepto de migración internacional, el cual se analiza desde distintos puntos de vista y autores. Segundo, se retoman los últimos 30 años de proceso histórico migratorio desde el departamento del Valle del Cauca al exterior. Tercero, se analiza el documento Conpes 3603, emitido por el Gobierno Nacional, en cabeza del Ministerio de Relaciones Exteriores, y se escruta sobre la influencia de este en las políticas formuladas e implementadas en el departamento. Cuarto, se enumeran algunas de las organizaciones gubernamentales, y no gubernamentales, más relevantes con las cuales trabaja el gobierno del Valle del Cauca para lograr el desarrollo de la Política Integral Migratoria (PIM en el departamento. Finalmente, el presente artículo pretende brindar algunas conclusiones, a modo de reflexión, sobre los retos que enfrenta la Política Integral Migratoria (PIM en el departamento.

  4. Petrogenesis of Rinjani Post-1257-Caldera-Forming-Eruption Lava Flows

    Directory of Open Access Journals (Sweden)

    Heryadi Rachmat

    2016-06-01

    Full Text Available DOI:10.17014/ijog.3.2.107-126After the catastrophic 1257 caldera-forming eruption, a new chapter of Old Rinjani volcanic activity beganwith the appearance of Rombongan and Barujari Volcanoes within the caldera. However, no published petrogeneticstudy focuses mainly on these products. The Rombongan eruption in 1944 and Barujari eruptions in pre-1944, 1966,1994, 2004, and 2009 produced basaltic andesite pyroclastic materials and lava flows. A total of thirty-one sampleswere analyzed, including six samples for each period of eruption except from 2004 (only one sample. The sampleswere used for petrography, whole-rock geochemistry, and trace and rare earth element analyses. The Rombonganand Barujari lavas are composed of calc-alkaline and high K calc-alkaline porphyritic basaltic andesite. The magmashows narrow variation of SiO2 content that implies small changes during its generation. The magma that formedRombongan and Barujari lavas is island-arc alkaline basalt. Generally, data show that the rocks are enriched in LargeIon Lithophile Elements (LILE: K, Rb, Ba, Sr, and Ba and depleted in High Field Strength Elements (HFSE: Y, Ti,and Nb which are typically a suite from a subduction zone. The pattern shows a medium enrichment in Light REEand relatively depleted in Heavy REE. The processes are dominantly controlled by fractional crystallization andmagma mixing. All of the Barujari and Rombongan lavas would have been produced by the same source of magmawith little variation in composition caused by host rock filter process. New flux of magma would likely have occurredfrom pre-1944 until 2009 period that indicates slightly decrease and increase of SiO2 content. The Rombongan andBarujari lava generations show an arc magma differentiation trend.

  5. Posoqoypata, un cementerio wari en el valle de Ayacucho, Perú

    Directory of Open Access Journals (Sweden)

    2001-01-01

    Full Text Available POSOQOYPATA, UN CIMETIÈRE WARI DE LA VALLEE D’AYACUCHO, PEROU. Nous avons récemment effectué un travail de sauvetage arquéologique dans un cimetière Wari de la vallée d’Ayacucho, ce qui a permis la mise à jour de deux formes mortuaires totalement nouvelles pour la région, et pour la culture Wari plus précisemment. La première consiste en une chambre funéraire de forme rectangulaire, avec un accès orienté à l’Est, et qui contenait les restes de plusieurs individus. La seconde est une petite sépulture en pierres de forme cylindrique qui contenait les restes d’un individu. Ce texte décrit les deux formes mortuaires et les compare avec les structures mortuaires Wari fouillées jusqu’à aujourd’hui dans la vallée d’Ayacucho. Étant donné qu’il est évident que la première forme mortuaire a été accessible, nous discutons ici les conséquences possibles pour l’adoration du corps des ancêtres, qui étaient conservés dans des structures mortuaires accessibles, cet élément étant considéré comme un aspect important de l’ayllu de l’époque Inka. Recientemente efectuamos un trabajo de rescate arqueológico en un cementerio Wari en el valle de Ayacucho. Dicho trabajo permitió el descubrimiento de formas mortuarias totalmente novedosas para la región y para la cultura Wari en particular. La primera consiste en una cámara funeraria de forma rectangular, con un acceso orientado hacia el lado este, y que contenía los restos de varios individuos. La segunda tiene la forma de una pequeña cista de forma cilíndrica que contenía los restos de un individuo. En este ensayo describimos ambas formas mortuarias y comparamos con las estructuras mortuarias Wari excavadas a la fecha en el valle de Ayacucho. Por cuanto la primera forma mortuaria fue evidentemente accesible, también discutimos sus posibles implicancias en torno a la adoración del cuerpo de los ancestros. Esto considerando que un aspecto importante del ayllu de la

  6. Evolution of silicic magmas in the Kos-Nisyros volcanic center, Greece: a petrological cycle associated with caldera collapse

    Science.gov (United States)

    Bachmann, Olivier; Deering, Chad D.; Ruprecht, Janina S.; Huber, Christian; Skopelitis, Alexandra; Schnyder, Cedric

    2012-01-01

    Multiple eruptions of silicic magma (dacite and rhyolites) occurred over the last ~3 My in the Kos-Nisyros volcanic center (eastern Aegean sea). During this period, magmas have changed from hornblende-biotite-rich units with low eruption temperatures (≤750-800°C; Kefalos and Kos dacites and rhyolites) to hotter, pyroxene-bearing units (>800-850°C; Nisyros rhyodacites) and are transitioning back to cooler magmas (Yali rhyolites). New whole-rock compositions, mineral chemistry, and zircon Hf isotopes show that these three types of silicic magmas followed the same differentiation trend: they all evolved by crystal fractionation and minor crustal assimilation (AFC) from parents with intermediate compositions characterized by high Sr/Y and low Nb content, following a wet, high oxygen fugacity liquid line of descent typical of subduction zones. As the transition between the Kos-Kefalos and Nisyros-type magmas occurred immediately and abruptly after the major caldera collapse in the area (the 161 ka Kos Plateau Tuff; KPT), we suggest that the efficient emptying of the magma chamber during the KPT drew out most of the eruptible, volatile-charged magma and partly solidified the unerupted mush zone in the upper crust due to rapid unloading, decompression, and coincident crystallization. Subsequently, the system reestablished a shallow silicic production zone from more mafic parents, recharged from the mid to lower crust. The first silicic eruptions evolving from these parents after the caldera collapse (Nisyros units) were hotter (up to >100°C) than the caldera-forming event and erupted from reservoirs characterized by different mineral proportions (more plagioclase and less amphibole). We interpret such a change as a reflection of slightly drier conditions in the magmatic column after the caldera collapse due to the decompression event. With time, the upper crustal intermediate mush progressively transitioned into the cold-wet state that prevailed during the Kefalos

  7. Incidencia del deterioro progresivo del arbolado urbano en el Valle de Aburrá, Colombia

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    Hector Ivan Restrepo Orozco

    2015-07-01

    Full Text Available El arbolado urbano de los municipios del Valle de Aburrá, Colombia, está evidenciando deterioro y muerte por estrés hídrico y térmico, contaminación atmosférica, urbanización y ataques de plagas y enfermedades. Se realizó un muestreo de 11 710 individuos de 25 especies de árboles y palmas en el área metropolitana del Valle de Aburrá, con el propósito de registrar síntomas de deterioro progresivo (DP como marchitez de ramas y secamiento descendente. Se estimó un modelo logit multifactorial que relaciona la incidencia del DP con características dasométricas de los individuos, el sitio de siembra y el número de afectaciones. Se encontraron 720 individuos con DP (incidencia de 6.1%. Los modelos logit tuvieron un ajuste satisfactorio a los datos y evidenciaron que existe una relación estadísticamente significativa entre la incidencia del deterioro de árboles y el diámetro del árbol, su ubicación (municipio, especie, sitio de siembra (zona verde, piso duro, alcorque y presencia de otras afectaciones.

  8. El saber de la partera tradicional del valle del río Cimitarra: cuidando la vida

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    CELMIRA LAZA VÁSQUEZ

    2009-12-01

    Full Text Available Para la recolección y análisis de la información se utilizaron la Etnografía focalizada y la técnica de Spradley y la teoría de la diversidad y la universalidad de los cuidados culturales de Leininger se tomó como referente teórico. Su objetivo fue describir los cuidados que brindaban las parteras tradicionales a partir de creencias y prácticas en las mujeres durante el parto en la zona rural de la región del valle del río Cimitarra, Magdalena Medio. El estudio se desarrolló en el valle del río Cimitarra y la ciudad de Barrancabermeja. Participaron siete parteras tradicionales y se recolectaron los datos mediante entrevista etnográfica y observación participante entre los años 2007 y 2008. El tema central es " El saber de la partera tradicional del valle del río Cimitarra: cuidando la vida" y cinco dominios culturales: alistarse para la atención del mismo, identificar el momento del parto, ayudar a la mujer a parir, proteger al bebé después del nacimiento y proteger a la mujer después del nacimiento. Cuidar la vida se relaciona con la necesidad de " sobrevivir" a pesar de la guerra, la violencia y el abandono estatal. Las acciones de cuidado se fundan en creencias culturales, la cotidianidad del trabajo del campo, la tradición oral y la invocación divina en medio del complejo contexto ambiental, la incertidumbre del conocmiento y el miedo a problemas legales.

  9. Caldera unrest driven by CO2-induced drying of the deep hydrothermal system.

    Science.gov (United States)

    Moretti, R; Troise, C; Sarno, F; De Natale, G

    2018-05-29

    Interpreting volcanic unrest is a highly challenging and non-unique problem at calderas, since large hydrothermal systems may either hide or amplify the dynamics of buried magma(s). Here we use the exceptional ground displacement and geochemical datasets from the actively degassing Campi Flegrei caldera (Southern Italy) to show that ambiguities disappear when the thermal evolution of the deep hydrothermal system is accurately tracked. By using temperatures from the CO 2 -CH 4 exchange of 13 C and thermodynamic analysis of gas ascending in the crust, we demonstrate that after the last 1982-84 crisis the deep hydrothermal system evolved through supercritical conditions under the continuous isenthalpic inflow of hot CO 2 -rich gases released from the deep (~8 km) magma reservoir of regional size. This resulted in the drying of the base of the hot hydrothermal system, no more buffered along the liquid-vapour equilibrium, and excludes any shallow arrival of new magma, whose abundant steam degassing due to decompression would have restored liquid-vapour equilibrium. The consequent CO 2 -infiltration and progressive heating of the surrounding deforming rock volume cause the build-up of pore pressure in aquifers, and generate the striking temporal symmetry that characterizes the ongoing uplift and the post-1984 subsidence, both originated by the same but reversed deformation mechanism.

  10. Paleogene and Neogene magmatism in the Valle del Cura region: New perspective on the evolution of the Pampean flat slab, San Juan province, Argentina

    Science.gov (United States)

    Litvak, Vanesa D.; Poma, Stella; Kay, Suzanne Mahlburg

    2007-09-01

    The Valle del Cura region is characterized by a thick volcanic and volcaniclastic sequence that records the Tertiary arc and backarc magmatic evolution of the Argentine Main Cordillera over the modern Pampean flatslab at 29.5-30°S. During the Eocene, a retroarc basin developed, represented by the Valle del Cura Formation synorogenic volcanosedimentary sequence, which includes rhyolites and dacitic tuffs. These silicic volcanic rocks have weak arc chemical signatures and high lithophile element concentrations and are isotopically enriched relative to the late Oligocene-early Miocene volcanic rocks that followed them. Their chemical characteristics fit with eruption through a thin crust. The Valle de Cura Formation was followed by the Oligocene-early Miocene Doña Ana Group volcanic sequence, which erupted at and near the arc front west of the border with Chile. The Doña Ana Group volcanic rocks have calc-alkaline chemical characteristics consistent with parental magmas forming in a mantle wedge and erupting through a normal thickness crust (35 km). Subsequent shallowing of the downgoing Nazca plate caused the volcanic front to migrate eastward. The volcanic sequences of the middle Miocene Cerro de las Tórtolas Formation erupted at this new arc front, essentially at the Argentine border. Two stages are recognized: an older one (16-14 Ma) in which magmas appear to have erupted through a normal thickness crust (30-35 km) and a younger one (13-10 Ma) in which the steeper REE pattern suggests the magmas last equilibrated with higher pressure residual mineral assemblages in a thicker crust. Isotopic ratios in the younger group are consistent with an increase in original crustal components and crust introduced into the mantle source by forearc subduction erosion. A peak in forearc subduction erosion near 12-10 Ma is consistent with when the main part of the Juan Fernandez Ridge began to subduct beneath the region. In addition to late Miocene Tambo Formation dacitic

  11. Material toughness, internal structure, and caldera-collapse frequencies in basaltic and composite edifices

    Energy Technology Data Exchange (ETDEWEB)

    Gudmundsson, Agust [Department of Earth Sciences, Queen' s Building, Royal Holloway University of London, Egham TW20 OEX (United Kingdom)], E-mail: a.gudmundsson@es.rhul.ac.uk

    2008-10-01

    Formation of, and slip on existing, collapse calderas is much more common in basaltic edifices than in composite edifices. I suggest that this difference is partly due to the composite edifices being tougher and more resistant to ring-fault formation than a basaltic edifices. The high matieral toughness of composite edifices is related to their being composed of rock layers with widely different elastic properties, the elastic mismatch promoting deflection and/or arrest of potential ring faults at layer contacts.

  12. Estudios sobre la enfermedad de Carrión en el valle interandino del Mantaro: I. Observaciones entomológicas

    Directory of Open Access Journals (Sweden)

    Aristides Herrer

    1960-01-01

    Full Text Available Durante los primeros meses de 1959 se presentó una epidemia de la enfermedad de Carrión o verruga peruana en el valle interandino del Mantaro, de preferencia en localidades próximas a la de Anco. Las investigaciones entomológicas realizadas al respecto han permitido conocer la existencia en dicha zona de dos especies de titiras, el Phlebotomus pescei y el P. bicornutus n. sp.; en cambio no se ha encontrado al P. verrucarum, conocido vector de la enfermedad de Carrión en el Perú. Las dos especies de titiras obtenidas en el Mantaro ingresan con frecuencia a las habitaciones humanas y se alimentan sobre el hombre y varias especies de animales, tanto domésticas como salvajes. Hay una marcada diferencia en cuanto a la distribución altitudinal de las dos especies de titiras del Mantaro. El P. bicornutus es abundante en las localidades de menor altitud sobre el nivel del mar y parece que el límite superior de su distribución se encuentra alrededor de los 2,600 metros. El P. pescei, en cambio, es una titira de mayor altura. Por debajo de los 2,400 metros es sumamente rara, entretanto que se le encuentra con mayor frecuencia entre los 2,600 y los 3,000 metros; a partir de esta altitud nuevamente se torna escasa hasta los 3,300 metros, altura máxima donde se le ha encontrado. Los lugares donde se ha verificado la mayoría de los casos de verruga, en el valle del Mantaro, por la altitud corresponden al de la distribución del P. pescei, por lo que es de suponer dicha titira actúe de trasmisora de la enfermedad de Carrión en el referido valle del Mantaro. En el valle del Mantaro, a niveles superiores al de la respectiva zona verrucógena existe una considerable población autóctona, parte de la cual anualmente desciende por espacio de algunas semanas a lugares donde la enfermedad de Carrión es endémica, lo que da lugar a numerosos casos de verruga. En noviembre de 1958 el Servicio Nacional de Erradicación de la Malaria aplicó el

  13. Distribución e identificación de especies hospedantes de Heterodera glycines Ichinohe raza 3 en el Valle del Cauca

    Directory of Open Access Journals (Sweden)

    Varón de Agudelo Francia

    1988-06-01

    Full Text Available Se dividió la parte plana del Valle del Cauca en tres zonas (norte, centro y sur, habiéndose visitado 33 fincas. En la zona norte las malezas con mayor porcentaje de frecuencia y distribución en los cultivos de soya fueron Digitaria horizontalis, Echinochloa colonum y Leptochloa filiformis; en la zona centro Ipomoea hirta, Amaranthus dubius y Echinochloa colonum y en la zona sur predominaron Ipomoea hirta, Portulaca oleracea Cyperus rotundus. Los análisis de muestras de suelo y raíces indicaron que H. glycines se encuentra distribuido en todo el Valle del Cauca, presentando la zona sur (Candelaria, Palmira y Puerto Tejada las mayores poblaciones. Entre las especies evaluadas (malezas, cultivos, leguminosas forrajeras y silvestres, solamente Glycine max y Phaseolus vulgaris se consideraron como susceptibles a H. glycines raza 3. y P. angularis y P. multiflora permitieron muy poca infección y multiplicación del nemátodo.A nematode recognition of Heterodera glycines was focused on crops of soybean. Valle del Cauca was divided in three zones (northen, central and southern and 33 farms were visited. The results of the analysis on samples of soils and roots showe that Heterodera glycines is scattered throughout Valle del Cauca, being the southern zone (Palmira, Candelaria and Puerto Tejada the one having the highest standards in nematode population. Weeds showing a greater frequency percentage were : Digitaria horizontalis, Echinochloa colonum and Leptochloa filiformis, in the northen zone; Ipomoea hirta, Amaranthus dubius and Echinochloa colonum, in the central zone, and Ipomoea hirta, Portulaca oleracea and Cyperus rotundus, in the southern zone , From among the whole species evaluated (weeds, crops, leguminous a n d fodder plants, Glycine max and Phaseolus vulgaris were considered to be susceptible to H. Glycines race 3. Phaseolus angularis y P. multiflora let low population levels.

  14. Primer registro de Phyllodactylus sentosus (Squamata: Phyllodactylidae para el valle del río Chillón, Lima, Perú

    Directory of Open Access Journals (Sweden)

    Diego Olivera

    2016-12-01

    Full Text Available El gecko de Lima Phyllodactylus sentosus (Dixon & Huey, 1970 identificado como en peligro crítico de extinción ha sido registrado sólo en algunas localidades entre los valles de los ríos Rímac y Lurín, en el centro y sur de la ciudad de Lima, Región Lima, sin embargo, su distribución hacia el norte no está documentada. En el presente trabajo se reporta por primera vez la presencia de P. sentosus en la Huaca Tambo Inga, ubicada en el margen derecho del valle del río Chillón en el distrito de Puente Piedra, extendiendo su distribución 19 km al noreste.

  15. Dynamics of uranium ore formation in the basement and frame of the Streltsovskaya Caldera

    International Nuclear Information System (INIS)

    Petrov, V.; Schukin, S.

    2014-01-01

    The analysis of geological-geophysical, paleo-geodynamics, mineralogical, geochemical, isotope, geochronological, and thermo-baro-geochemical data allow us to offer a model of uranium ore formation dynamics in the basement and frame of the Streltsovskaya Caldera connected to activity of the fluid-conducting fault zones network with the aim to identify prospective areas The most ancient fluid-conducting structures are inter-block NE-SW, NNE-submeridional, NW-SE and, probably, WNW-sub-latitudinal faults. The oldest NE-SW faults and schistosity zones were formed during Proterozoic tectonic cycle (TC) with reactivation in T3-J2 time due to global reorganization of stress field and reactivation of tectonic movements. The NNE-submeridional and NW-SE faults were extended with increased fluid permeability during Caledonian and Variscan TCs. They also were reactivated in the process of Late Mesozoic tectonic and magmatic activation (TMA). Thus already at early stages of geotectonic evolution within the intersection of NE-SW (N-Urulyunguyevskiy fault) and NNE-submeridional (Chindachinskaya zone) faults the areas of increased fluid and magmatic activity were formed. The dynamics of fault formation in the basement and frame of the Streltsovskaya caldera and its volcano-sedimentary cover differs. In the basement and granite framework NE-SW, NNEsubmeridional and NW-SE faults are interblock structures of the I rank. Their intersection formed areas of long-term circulation of hydrothermal solutions and telescopic appearance of multi-age metasomatites that created conditions for localizing of vein-stockwork mineralization. In volcanosedimentary cover the NE-SW and NNE-submeridional faults should be considered as interblock structures of the I rank where intersections provided inflow of ore-bearing solutions and their redistribution within the cover. Here the main ore distributing role belongs to NW-SE shears. They are intrablock II rank structures which were formed due to dextral

  16. Yacimientos de Celestina en la Plataforma Valles-San Luis Potosí

    OpenAIRE

    Rocha Rocha, Macario

    2008-01-01

    En la zona de estudio, la Plataforma Valles-San Luis Potosí (PVSLP), existen depósitos de celestina; las características geotectónicas de la zona, hacen pensar que estos depósitos se asocian con evaporitas del Jurásico Superior-Cretácico Inferior. La mineralización de celestina arma en la Formación El Abra y en menor grado la Formación Indidura, en forma de vetas, mantos, zonas de brecha y cuerpos irregulares. La mineralogía consiste básicamente de celestina y algunos minerales...

  17. Relaciones productivas y configuración de la política sectorial en el Valle de Aburrá

    Directory of Open Access Journals (Sweden)

    Marleny Cardona Acevedo

    2001-01-01

    el artículo muestra la influencia de los procesos productivos y las condiciones tecnológicas de las empresas en la capacidad directiva y en la organización del trabajo en empresas industriales asentadas en el Valle de Aburrá, Colombia.

  18. A 2-D FEM thermal model to simulate water flow in a porous media: Campi Flegrei caldera case study

    Directory of Open Access Journals (Sweden)

    V. Romano

    2012-05-01

    Full Text Available Volcanic and geothermal aspects both exist in many geologically young areas. In these areas the heat transfer process is of fundamental importance, so that the thermal and fluid-dynamic processes characterizing a viscous fluid in a porous medium are very important to understand the complex dynamics of the these areas. The Campi Flegrei caldera, located west of the city of Naples, within the central-southern sector of the large graben of Campanian plain, is a region where both volcanic and geothermal phenomena are present. The upper part of the geothermal system can be considered roughly as a succession of volcanic porous material (tuff saturated by a mixture formed mainly by water and carbon dioxide. We have implemented a finite elements approach in transient conditions to simulate water flow in a 2-D porous medium to model the changes of temperature in the geothermal system due to magmatic fluid inflow, accounting for a transient phase, not considered in the analytical solutions and fluid compressibility. The thermal model is described by means of conductive/convective equations, in which we propose a thermal source represented by a parabolic shape function to better simulate an increase of temperature in the central part (magma chamber of a box, simulating the Campi Flegrei caldera and using more recent evaluations, from literature, for the medium's parameters (specific heat capacity, density, thermal conductivity, permeability. A best-fit velocity for the permeant is evaluated by comparing the simulated temperatures with those measured in wells drilled by Agip (Italian Oil Agency in the 1980s in the framework of geothermal exploration. A few tens of days are enough to reach the thermal steady state, showing the quick response of the system to heat injection. The increase in the pressure due to the heat transport is then used to compute ground deformation, in particular the vertical displacements characteristics of the Campi Flegrei caldera

  19. Producción y desarrollo de nueve variedades de naranja Citrus sinensis (L. Osbeck en la zona plana del Valle del Cauca

    Directory of Open Access Journals (Sweden)

    Salazar C. Raúl

    1990-12-01

    Full Text Available En árboles de naranja de cinco años injertados sobre mandarina Cleopatra, se evaluaron nueve variedades sembradas en un diseño experimental de bloques completos al azar. El crecimiento de los frutos presentó las tres fases típicas, con duración variable dependiendo de la variedad: lento, crecimiento acelerado y estabilización. Los máximos crecimientos se obtuvieron en las variedades Old Vini, Valencia y Valle Washington. En todas las variedades los sólidos solubles disminuyeron y el porcentaje de acidez aumentó hasta ciertos límites con la edad del fruto. Considerando como momento óptimo para iniciar la cosecha una relación de sólidos solubles: acidez de 9.5:1, la más temprana fue la Valle Washington (7.5 meses, intermedias Old Vini y Australia Navel y la más tardía García Valencia. Todas las variedades presentaron contenidos de jugo mayores del 50 % Y color atractivo de la pulpa. El color más atractivo de la corteza se obtuvo en Parson Brown (97.5 % amarillo, las otras variedades fluctuaron entre 48 y 79%. Todas las variedades tuvieron menos de seis semillas por fruto. Se presentaron dos épocas de cosecha y las variedades con mayor producción: Hamlin, García Valencia y Pineapple tuvieron la mayor variación mensual. La mejor alternativa sembrando 90% de variedades para industria y 10 % para mesa se obtuvo con las variedades Pineapple, Hamlin, Parson Brown, Valle Washington y Old Vini.Five years old orange trees, were grafted on Cleopatra scions of nine cultivars planted in a completely randomized block design were evaluated. Fruit growths presented three typical phases of variable lenght, depending on the cultivar: slow , rapid and stable growth rates. Largest growth were observed in the old Vini, Valencia and Valle Washington cultivars. In all cases total soluble solid contents and acidity increased, up to certain point, with fruit age. Considering that the optimum time to iniciate cropping is when the relationship

  20. Magnetostratigraphy of the Vallesian (late Miocene) in the Vallès-Penedès Basin (northeast Spain)

    Science.gov (United States)

    Garcés, M.; Agustí, J.; Cabrera, L.; Parés, J. M.

    1996-08-01

    The magnetostratigraphic analysis of the late Miocene continental deposits from the Vallès-Penedès Basin, combined with its well-documented fossil mammal record, has provided a well-resolved chronology for the upper basin infill. The study is based on the biostratigraphic and magnetostratigraphic cross-correlation of 12 sections throughout the alluvial sequences in the western Vallès area. The biostratigraphic framework consists of 21 mammal localities corresponding to the Mammal Neogene MN9 and MN10 units. The composite magnetic polarity sequence is based on 400 paleomagnetic sites. Correlation with the Geomagnetic Polarity Time Scale (GPTS) has led to an absolute dating of the faunal events and a precise chronostratigraphy of the Vallesian mammal stage in its type area. The Hipparion First Appearance Datum (FAD), at the MN8/MN9 boundary, is dated at 11.1 Ma in the Vallès-Penedès Basin. This age, compared to other radiometrically dated localities in Europe, North Africa and Turkey, is consistent with an isochronous dispersal of this equid through the Mediterranean region. A possible isochrony at a larger geographical scale (Old World, Mesogea) must await more reliable ages of the Hipparion FAD in Asia and Africa. The Cricetulodon FAD ( MN9a/MN9b boundary) is dated to 10.4 Ma, in chron C5n. The Progonomys FAD ( MN9/MN10 boundary), corresponding to the intra-Vallesian faunal crisis, is dated at 9.7 Ma (C4Ar.3r). The Vallesian spans 2.4 Myr, from 11.1 Ma (C5r.1n) to 8.7 Ma (C4An) and correlates to the early Tortonian.

  1. Studies on nanosecond 532nm and 355nm and ultrafast 515nm and 532nm laser cutting super-hard materials

    Science.gov (United States)

    Zhang, Jie; Tao, Sha; Wang, Brian; Zhao, Jay

    2017-02-01

    In this paper, micro-processing of three kinds of super-hard materials of poly-crystal diamond (PCD)/tungsten-carbide (WC), CVD-diamond and cubic boron nitride (CNB) has been systematically studied using nanosecond laser (532nm and 355nm), and ultrafast laser (532nm and 515nm). Our purpose is to investigate a full laser micro-cutting solution to achieve a ready-to-use cutting tool insert (CTI). The results show a clean cut with little burns and recasting at edge. The cutting speed of 2-10mm/min depending on thickness was obtained. The laser ablation process was also studied by varying laser parameters (wavelength, pulse width, pulse energy, repetition rate) and tool path to improve cutting speed. Also, studies on material removal efficiency (MRE) of PCD/WC with 355nm-ns and 515nm-fs laser as a function of laser fluence show that 355nm-ns laser is able to achieve higher MRE for PCD and WC. Thus, ultrafast laser is not necessarily used for superhard material cutting. Instead, post-polishing with ultrafast laser can be used to clean cutting surface and improve smoothness.

  2. Paisajes del Valle medio del Guadalquivir cordobés: Funcionalidad y cambios

    OpenAIRE

    Martín Torres Márquez

    2013-01-01

    RESUMEN: Los tradicionales paisajes agrarios del Valle cordobés, ligados a la presencia del Guadalquivir, han sido importantes y tempranas áreas de modernización económica, gracias al desarrollo de la agricultura, el regadío y la industrialización. Sin embargo, esas funciones agrarias, antaño inseparables de la identidad paisajística de los ruedos y el extrarradio de Córdoba, se hallan en retroceso desde el último tercio del siglo XX, un retroceso provocado por la expansión de la ciudad difu...

  3. Paisajes del Valle medio del Guadalquivir cordobés: Funcionalidad y cambios

    OpenAIRE

    Torres-Márquez, Martín

    2013-01-01

    Los tradicionales paisajes agrarios del Valle cordobés, ligados a la presencia del Guadalquivir, han sido importantes y tempranas áreas de modernización económica, gracias al desarrollo de la agricultura, el regadío y la industrialización. Sin embargo, esas funciones agrarias, antaño insepa- rables de la identidad paisajística de los ruedos y el extrarradio de Córdoba, se hallan en retroceso desde el último tercio del siglo XX, un retroceso provocado por la expansión de la ciud...

  4. Stratigraphy and AMS radiocarbon dates of cored sediments (IrBH-2) from the Irosin caldera, the Philippines

    International Nuclear Information System (INIS)

    Mirabueno, Ma. Hannah T.; Laguerta, Eduardo P.; Delos Reyes, Perla J.; Bariso, Ericson B.; Torii, Masayuki; Fujiki, Toshiyuki; Okuno, Mitsuru; Nakamura, Toshio; Danhara, Tohru; Saito-Kokubu, Yoko; Kobayashi, Tetsuo

    2014-01-01

    Core drilling at Site IrBH-2 within the Irosin caldera in Sorsogon Province, southern Luzon reached a depth of 50 m. Systematic logging and documentation were carried out to describe and interpret the sediments. The accelerator mass spectrometer (AMS) radiocarbon dates obtained from plant fragments at 7.02-10.40-m depth were 1000 to 1800 BP. Lahars and fluvial deposits were the predominant deposits in the core sequence. The upper 12 m consisted mostly of andesitic fluvial and minor lahar deposits. These deposits may be correlated with the reworking of eruptive products from resurgent andesitic volcanism. One pyroclastic flow and 12 fallout deposits, including five possible fallout deposits, were intercalated with reworked sediments at depths of 12-50 m. The refractive index of representative samples indicated that post-caldera eruptions involved mainly andesite to dacite, with minor rhyolite magmas. The rhyolite fallout in the core had similar petrographic characteristics to the 41 cal kBP Irosin ignimbrite, suggesting that the fallout and the ignimbrite were sourced from the same magma. (author)

  5. Thermal environment characterization for the bovine cattle ranching in the Valle del Cauca, Colombia

    Directory of Open Access Journals (Sweden)

    Raúl Andres Molina Benavides

    2016-10-01

    Full Text Available The influence of climate on animal behavior has been demonstrated for many years. Climatic variables such as temperature (T, ° C, relative humidity (RH, %, solar radiation (SR, W / m2 and wind speed (WS, m / s, outside their normal range, can displace ruminants of their comfort zone, which can results in negative impact on their productivity and reproduction behavior. In order to characterize the thermal environment of bovine cattle ranching in the Valle del Cauca department, two biometeorological indexes (heat load index for dairy cows and meat cattle were performed to develop an animal - environment relationship. The indexes were applied to the most representative Valle del Cauca department climatic ranges (T = 20-35; RH = 60-100; WS = 0-10, finding that for dairy cows under the mentioned conditions of T> 23, RH> 80 and 0 WS, starting to show signals of heat stress, while for beef cattle starts with T> 25, RH> 60 and WS <1.5. In conclusion, these indexes are useful tools to determine the degree of heat stress that may occur on farms during certain times of day for certain months of the year, helping to plan actions to control its effect in cattle and subsequently, mitigate the impacts on their productive and reproductive performance.

  6. Impacto de la calidad total como teoría de la gestión en las sociedades anónimas del Valle de Aburrá

    Directory of Open Access Journals (Sweden)

    Omar de Jesús González

    1996-02-01

    Full Text Available RESUMEN El objetivo general de este trabajo es Determinar el Impacto de la calidad total como teoría de la gestión en las sociedades anónimas  del Valle de Aburrá. Específicamente el trabajo busca determinar cuántas S.A. del Valle de Aburrá, afiliadas a la corporación  Calidad y/o al Grupo Antioquia  para el Mejoramiento Continuo, han estructurado o están estrucutrando un plan estretégico de Calidad Total.

  7. Individualismo y desconfianza en el trabajo asociativo de cadenas productivas de agroexportacion en el Valle del Mantaro, Junín, Perú

    Directory of Open Access Journals (Sweden)

    William Rodríguez Giráldez

    2014-12-01

    Full Text Available Objetivos: Determinar el individualismo y desconfianza en el trabajo asociativo de cadenas productivas de agroexportación en el Valle del Mantaro. Métodos: Investigación descriptiva, no experimental, de alcance transeccional correlacional. Fueron encuestados 383 productores agrícolas de las provincias que comprenden el Valle del Mantaro: Huancayo, Concepción, Jauja y Chupaca. Se utilizaron los estadísticos descriptivos, distribución de frecuencias, tablas de contingencia, y chi cuadrado para prueba de hipótesis. Resultados: En la dimensión individualismo: 72,23 % de productores manifestaron una actitud positiva hacia cadenas productivas; 87,2 % estimaron importante participar en reuniones; 88,5 % consideraron importante la capacitación en asociatividad y 86,2 % gustan trabajar conjuntamente con vecinos. Se deduce que el 83,53 % de ellos no tienen el rasgo de individualismo; por tanto, solo el 16,47 % tienen este rasgo y no influye negativamente en el trabajo asociativo en el Valle del Mantaro. En la dimensión desconfianza: 52 % de productores agrícolas manifestaron buena comunicación en la cadena productiva; 40 % aportaron entre 50 % y 100 % de costos de producción; 56 % podrían aportar entre 50 % y 100 % de costos de producción; 60 % señalaron que confían en empresas articuladoras y 60 % confían en colegas productores. Se deduce que, 53,6 % de estos productores no poseen el rasgo de desconfianza; mientras que 46,4 % si los tienen. Conclusiones: Solo 16,47 % de productores agrícolas tienen rasgos de individualismo y no influye negativamente en el trabajo asociativo; 46,4 % de estos productores tienen el rasgo de desconfianza y este valor sí influye negativamente en el trabajo asociativo en el valle.

  8. Mega-rings Surrounding Timber Mountain Nested Calderas, Geophysical Anomalies: Rethinking Structure and Volcanism Near Yucca Mountain (YM), Nevada

    Science.gov (United States)

    Tynan, M. C.; Smith, K. D.; Savino, J. M.; Vogt, T. J.

    2004-12-01

    Observed regional mega-rings define a zone ˜80-100 km in diameter centered on Timber Mountain (TM). The mega-rings encompass known smaller rhyolitic nested Miocene calderas ( ˜11-15 my, structural relationships. Mega-rings consist of arcuate faulted blocks with deformation (some remain active structures) patterns showing a genetic relationship to the TM volcanic system; they appear to be spatially associated and temporally correlated with Miocene volcanism and two geophysically identified crustal/upper mantle features. A 50+ km diameter pipe-like high velocity anomaly extends from crustal depth to over 200 km beneath TM (evidence for 400km depth to NE). The pipe is located between two ˜100 km sub-parallel N/S linear trends of small-magnitude earthquake activity, one extending through the central NV Test Site, and a second located near Beatty, NV. Neither the kinematics nor relational mechanism of 100km seismically active N/S linear zones, pipe, and mega-rings are understood. Interpreted mega-rings are: 1) Similar in size to larger terrestrial volcanic complexes (e.g., Yellowstone, Indonesia's Toba system); 2) Located in the region of structural transition from the Mohave block to the south, N/S Basin and Range features to the north, Walker Lane to the NW, and the Las Vegas Valley shear zone to the SE; 3) Associated with the two seismically active zones (similar to other caldera fault-bounded sags), the mantle high velocity feature, and possibly a regional bouguer gravity anomaly; 4) Nearly coincident with area hydrologic basins and sub-basins; 5) Similar to features described from terrestrial and planetary caldera-collapse studies, and as modeled in laboratory scaled investigations (ice melt, balloon/sand). Post Mid-Miocene basalts commonly occur within or adjacent to the older rhyolitic caldera moats; other basaltic material occurs marginal to both the outer rings of the interpreted mega-ring system and high velocity pipe. The YM repository may be situated in

  9. Descriptions and records of Cladiopsocidae and Dolabellopsocidae (Insecta: Psocodea: 'Psocoptera') from Valle del Cauca and National Natural Park Gorgona, Colombia.

    Science.gov (United States)

    Calderón-Martínez, Nadia R; González-Obando, Ranulfo; Aldrete, Alfonso N García

    2014-11-28

    The results of a survey on the species diversity of the families Cladiopsocidae and Dolabellopsocidae (Psocodea: 'Psocoptera': Psocomorpha: Epipsocetae) in Valle del Cauca and in the National Natural Park (NNP) Gorgona, Colombia, are presented. The specimens studied were collected in the context of two scientific projects, in which 12 species in the two families were identified, five in Cladiopsocidae and seven in Dolabellopsocidae. In the first family, Cladiopsocus presented a new record in the country and four new species; in the latter, two genera were identified, Dolabellopsocus, with three new species and two new records, and Isthmopsocus, with two new species. This study presents the description of the nine new species from Valle del Cauca and NNP Gorgona, the new records for Colombia and identification keys to the neotropical species of both families.

  10. The link between volcanism and plutonism in epizonal magma systems; high-precision U–Pb zircon geochronology from the Organ Mountains caldera and batholith, New Mexico

    Science.gov (United States)

    Rioux, Matthew; Farmer, Lang; Bowring, Samuel; Wooton, Kathleen M.; Amato, Jeffrey M.; Coleman, Drew S.; Verplanck, Philip L.

    2016-01-01

    The Organ Mountains caldera and batholith expose the volcanic and epizonal plutonic record of an Eocene caldera complex. The caldera and batholith are well exposed, and extensive previous mapping and geochemical analyses have suggested a clear link between the volcanic and plutonic sections, making this an ideal location to study magmatic processes associated with caldera volcanism. Here we present high-precision thermal ionization mass spectrometry U–Pb zircon dates from throughout the caldera and batholith, and use these dates to test and improve existing petrogenetic models. The new dates indicate that Eocene volcanic and plutonic rocks in the Organ Mountains formed from ~44 to 34 Ma. The three largest caldera-related tuff units yielded weighted mean 206Pb/238U dates of 36.441 ± 0.020 Ma (Cueva Tuff), 36.259 ± 0.016 Ma (Achenback Park tuff), and 36.215 ± 0.016 Ma (Squaw Mountain tuff). An alkali feldspar granite, which is chemically similar to the erupted tuffs, yielded a synchronous weighted mean 206Pb/238U date of 36.259 ± 0.021 Ma. Weighted mean 206Pb/238U dates from the larger volume syenitic phase of the underlying Organ Needle pluton range from 36.130 ± 0.031 to 36.071 ± 0.012 Ma, and the youngest sample is 144 ± 20 to 188 ± 20 ka younger than the Squaw Mountain and Achenback Park tuffs, respectively. Younger plutonism in the batholith continued through at least 34.051 ± 0.029 Ma. We propose that the Achenback Park tuff, Squaw Mountain tuff, alkali feldspar granite and Organ Needle pluton formed from a single, long-lived magma chamber/mush zone. Early silicic magmas generated by partial melting of the lower crust rose to form an epizonal magma chamber. Underplating of the resulting mush zone led to partial melting and generation of a high-silica alkali feldspar granite cap, which erupted to form the tuffs. The deeper parts of the chamber underwent continued recharge and crystallization for 144 ± 20 ka after the

  11. Fluid circulation and structural system of Cerritos Colorados geothermal field in La Primavera volcanic caldera (Mexico) inferred from geophysical surveys

    Science.gov (United States)

    Bolós, X.; Cifuentes-Nava, G.; Macias, J. L.; Sosa-Ceballos, G.; García-Tenorio, F.; Albor, M., III; Juarez, M.; Gamez, V.

    2017-12-01

    Hydrothermal activity in volcanic calderas is the consequence of energy transfer between deep magmatic chambers and subsurface layers saturated in water. This hydrothermal system is generated by convection of the groundwater supplied by meteoric water recharged and the ascent of hot volcanic gasses exsolved from deep magma reservoirs. Calderas are heterogeneous geological structures that due to their formation and evolution produced a complex stratigraphy. All of these heterogeneities can be affected by deformation and also by the presence of fractures and faults which constitute the main pathways whereby hydrothermal fluids can move easily through the surface as spring discharges and fumarolic activity. Geophysical methods have been used in the last decades to investigate the relationship between structural geology and hydrothermal systems in different volcanic areas around the world. In this work, we have focused on the role of subsurface structures to understand and localize the pathways of fluids related to the hydrothermal system of the Cerritos Colorados geothermal field. We focused in the central area of the caldera (P12 well and Cerritos Colorados graben), where active hydrothermal activity is evidenced by fumaroles, thermal anomalies, CO2 diffuse emission, and sulfur precipitation. We have applied a self-potential method (SP) that combined with temperature measurements that allowed to identify the main infiltration and ascending fluid zones in the area, and their specific surface temperature coinciding with fumarolic activity. From this data we an applied Electrical Resistivity Tomography (ERT) survey in two selected places. One ERT profile (1.2 km in length) was located in the P12 well area. A 3D resistivity model used with the equatorial method was carried out on the Cerritos Colorados graben area. Combining the results of the SP, TºC, and ERT data with a detailed structural map we identified the main degassing zones (i.e. fumaroles) that correspond to

  12. Système d'information agricole dans la vallée de Huaral, au Pérou ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Evaluación del componente "Investigación aplicativa" del proyecto "Sistema de Información Agraria - SIA, a favor de los Pequeños Agricultores del Valle de Huaral" : el uso de "smartphones" en el medio rural como herramienta para el acceso a la... Téléchargez le PDF. Rapports. Sistema de información agraria : SIA del ...

  13. Traces of the Book Vatican Policy in the Manuscript File of Ramón del Valle-Inclán

    Directory of Open Access Journals (Sweden)

    Amparo de Juan Bolufer

    2017-01-01

    Full Text Available In various interviews done in 1933 Valle-Inclán said he was preparing a book for the historic series El Ruedo Ibérico that would explore the influence of the Vatican in Spanish politics. This article seeks to examine the traces of this narrative plan that have been preserved in the manuscript file belonging to the Valle-Inclán Alsina family, because we know that the writer continued to work on this historical project until his death. After examining the indirect documentation located primarily in the periodical press which bears witness to the process of writing this never published story, we will describe the unknown plans of structure and the drafts of work that are part of this creation file and that allow us to perceive the plot lines as well as the fundamental features of characterization for the prominent protagonists in this incomplete project.

  14. Studying Disability and Disability Studies: Shifting Paradigms of LD -- A Synthesis of Responses to Reid and Valle

    Science.gov (United States)

    Connor, David J.

    2005-01-01

    In this article, I discuss the 11 diverse responses to Reid and Valle's work on the discursive practice of learning disabilities (LD), implications for instruction, and parent-school relations. I highlight key ideas from each article and then focus on three common areas of interest shared by most respondents: the unacceptable status quo of…

  15. SEROPREVALENCIA Y SEROTIPIFICACIÓN DE LEPTOSPIROSIS CANINA EN EL MUNICIPIO DE BUENAVENTURA (VALLE DEL CAUCA)

    OpenAIRE

    Romero Peñuela, Marlyn Hellen; Astudillo Hernández, Myriam; Quintero Martínez, Mauricio Elías

    2009-01-01

    El presente estudio tuvo como objetivo verificar la infección con serovares de Leptospira spp. en caninos con propietario en Buenaventura, Valle del Cauca, Colombia. Las muestras de suero fueron tomadas de 100 caninos y fueron probadas con los serogrupos de Leptospira interrogans: Bataviae, Mini, Autumnalis, Canicola, Shermani, Icterohaemorrhagiae, Cynopteri, Australis, Celledonis, Grippotyphosa, Hebdomadis, Javanica, Manhao, Pomona, Pyrogenes, Sejroe, Tarassovi y Ballum, usando la técnica de...

  16. Pueblos, rituales y condiciones de vida prehispánicas en el Valle del Cauca

    OpenAIRE

    Rodríguez Cuenca, José Vicente

    2005-01-01

    El Valle del Cauca estuvo habitado por diversos pueblos que desarrollaron ingeniosas estrategias adaptativas con el propósito de mantener el equilibrio homeostasis entre la producción de recursos y su consumo. Los sacrificios humanos, las cabezas trofeo, el canibalismo ritual, los festejos asociados a las cosechas, los rituales funerarios, el sostenimiento de tierras de nadie en áreas fronterizas, los mismos combates organizados entre grupos rivales, la exogamia, la reprocidad y el intercambi...

  17. Rubén Darío y Valle-Inclán Diálogo intercultural // Rubén Darío and Valle-Inclán: An intercultural dialogue

    Directory of Open Access Journals (Sweden)

    José María Paz Gago

    2016-12-01

    Full Text Available The author discusses the relationship between two writers, representatives of literature at the turn of the twentieth century, seen as a dialogue both human and intercontinental. The Spaniard Valle-Inclán and the Nicaraguan Darío developed the inheritance of late Romanticism and decadence, they were formed during the epoch of symbolism and French parnasism, and participated in the constitution of Hispanic modernism. The essay offers a commentary on several texts they dedicated to each other, which create an authentic intercultural dialogue.

  18. Transpiration characteristics of forests and shrubland under land cover change within the large caldera of Mt. Aso, Japan

    Science.gov (United States)

    Miyazawa, Y.; Inoue, A.; Maruyama, A.

    2013-12-01

    Grassland within a caldera of Mt. Aso has been maintained for fertilizer production from grasses and cattle feeding. Due to the changes in the agricultural and social structure since 1950's, a large part of the grassland was converted to plantations or abandoned to shrublands. Because vegetations of different plant functional types differ in evapotranspiration; ET, a research project was launched to examine the effects of the ongoing land use change on the ET within the caldera, and consequently affect the surface and groundwater discharge of the region. As the part of the project, transpiration rate; E of the major 3 forest types were investigated using sap flow measurements. Based on the measured data, stomatal conductance; Gs was inversely calculated and its response to the environmental factors was modeled using Jarvis-type equation in order to estimate ET of a given part of the caldera based on the plant functional type and the weather data. The selected forests were conifer plantation, deciduous broadleaved plantation and shrubland, which were installed with sap flow sensors to calculate stand-level transpiration rate. Sap flux; Js did not show clear differences among sites despite the large differences in sapwood area. In early summer solar radiation was limited to low levels due to frequent rainfall events and therefore, Js was the function of solar radiation rather than other environmental factors, such as vapor pressure deficit and soil water content. Gs was well regressed with the vapor pressure deficit and solar radiation. The estimated E based on Gs model and the weather data was 0.3-1.2 mm day-1 for each site and was comparable to the E of grassland in other study sites. Results suggested that transpiration rate in growing was not different between vegetations but its annual value are thought to differ due to the different phenology.

  19. Receiver-operating characteristic curves for somatic cell scores and California mastitis test in Valle del Be lice dairy sheep

    NARCIS (Netherlands)

    Riggio, V.; Pesce, L.L.; Morreale, S.; Portolano, B.

    2013-01-01

    Using receiver-operating characteristic (ROC) curve methodology this study was designed to assess the diagnostic effectiveness of somatic cell count (SCC) and the California mastitis test (CMT) in Valle del Belice sheep, and to propose and evaluate threshold values for those tests that would

  20. Fraccionamiento de nitrógeno en frijol ( phaseolus vulgaris l. en el valle de san juan

    Directory of Open Access Journals (Sweden)

    Juan Cedano

    2000-01-01

    Full Text Available Fraccionamiento de nitrógeno en frijol (Phaseolus vulgaris L. en el valle de San Juan. Se realizó un estudio para determinar el efecto del fraccionamiento de la fertilización nitrogenada y el momento adecuado para la aplicación de nitrógeno en el cultivo de frijol (Phaseolus vulgaris L. en cinco localidades del Valle de San Juan, R. D. Los experimentos fueron establecidos del 5 al 14 de noviembre (1997 , se utilizó un diseño de bloques completamente al azar y nueve tratamientos en cada localidad, encontrándose que en los terrenos con altos niveles de nitrógeno no hubo respuesta a la aplicación de nitrógeno ni al fraccionamiento de este nutrimento; mientras que en los suelos con deficiencia en nitrógeno si hubo respuesta a la fertilización nitrogenada encontrándose diferencia estadística significativa a la aplicación y al momento de aplicación del fertilizante. Entre las localidades hubo diferencia estadística significativa (P>0.05, mientras que no se encontró interacción entre los tratamientos y las localidades

  1. Determinantes del trabajo infantil y la escolaridad: el caso del Valle del Cauca en Colombia

    Directory of Open Access Journals (Sweden)

    Sebastián Urueña Abadía

    2009-10-01

    Full Text Available Colombia, al igual que la mayoría de países latinoamericanos, consciente de las repercusiones sociales y económicas negativas del trabajo infantil, se ha comprometido en la lucha por la erradicación de este fenómeno. Prueba de ello es la ratificación por parte del gobierno colombiano en el año 2007, del Convenio 182 de la OIT sobre la Prohibición de las Peores Formas de Trabajo Infantil y la Acción Inmediata para su Eliminación. En el plano regional, como parte del Plan de Desarrollo del Departamento del Valle del Cauca 2008-2011, se está implementando actualmente una estrategia territorial de erradicación del trabajo infantil en sus 42 municipios. Considerando este panorama, este trabajo indaga cuáles son los determinantes del trabajo infantil y la escolaridad en el departamento del Valle a partir de los datos de la Encuesta Nacional de Calidad de Vida del año 2003. Para el análisis se emplea un modelo econométrico Probit Bivariado, que permite el estudio conjunto e interrelacionado de decisiones diferentes, en este caso la asistencia escolar y el trabajo.

  2. Materials for the study of the bronze age in the valley of the Vinalopo (Alicante | Materiales para el estudio de la Edad del Bronce en el Valle Medio del Vinalopó (Alicante | Materiales para el estudio de la Edad del Bronce en el Valle Medio del Vinalopó (Alicante

    Directory of Open Access Journals (Sweden)

    Juan Francisco Navarro Mederos

    1982-12-01

    Full Text Available Se presenta un grupo de poblados del Bronce en el Valle Medio del Vinalopó, provincia de Alicante, y los materiales procedentes de ellos y conservados en colecciones privadas. Su conocimiento permite incluir esta comarca en la cultura del Bronce Valenciano —aunque manteniendo una cierta personalidad— y aventurar hipótesis sobre la dinámica de la Edad del Bronce a lo largo de la cuenca del Vinalopó, sus contactos exteriores, las fronteras con el mundo argárico e intentar ordenarlos cronológicamente en base a un esquema propuesto para la globalidad del Bronce Valenciano. | L'article offre l'étude d'un groupe de sites de l'âge du Bronze dans la vallée du Vinalopó et des matériaux archéologiques conservés dans des collections privées. Des resultats de cet étude on peut inférer l'appartenance de cette zone a la civilisation du Bronze Valenciano, tout en conservant des traits individuants, et aussi tenter d'expliquer la dynamique de l'âge du Bronze au long de la vallée du Vinalopó, ses rapports extérieurs et la frontière avec la civilisation de l'Argar. On donne également une tentative de chronologie fondee sur un schéma global pour le Bronze Valenciano.

  3. Assessing future vent opening locations at the Somma-Vesuvio volcanic complex: 2. Probability maps of the caldera for a future Plinian/sub-Plinian event with uncertainty quantification

    Science.gov (United States)

    Tadini, A.; Bevilacqua, A.; Neri, A.; Cioni, R.; Aspinall, W. P.; Bisson, M.; Isaia, R.; Mazzarini, F.; Valentine, G. A.; Vitale, S.; Baxter, P. J.; Bertagnini, A.; Cerminara, M.; de Michieli Vitturi, M.; Di Roberto, A.; Engwell, S.; Esposti Ongaro, T.; Flandoli, F.; Pistolesi, M.

    2017-06-01

    In this study, we combine reconstructions of volcanological data sets and inputs from a structured expert judgment to produce a first long-term probability map for vent opening location for the next Plinian or sub-Plinian eruption of Somma-Vesuvio. In the past, the volcano has exhibited significant spatial variability in vent location; this can exert a significant control on where hazards materialize (particularly of pyroclastic density currents). The new vent opening probability mapping has been performed through (i) development of spatial probability density maps with Gaussian kernel functions for different data sets and (ii) weighted linear combination of these spatial density maps. The epistemic uncertainties affecting these data sets were quantified explicitly with expert judgments and implemented following a doubly stochastic approach. Various elicitation pooling metrics and subgroupings of experts and target questions were tested to evaluate the robustness of outcomes. Our findings indicate that (a) Somma-Vesuvio vent opening probabilities are distributed inside the whole caldera, with a peak corresponding to the area of the present crater, but with more than 50% probability that the next vent could open elsewhere within the caldera; (b) there is a mean probability of about 30% that the next vent will open west of the present edifice; (c) there is a mean probability of about 9.5% that the next medium-large eruption will enlarge the present Somma-Vesuvio caldera, and (d) there is a nonnegligible probability (mean value of 6-10%) that the next Plinian or sub-Plinian eruption will have its initial vent opening outside the present Somma-Vesuvio caldera.

  4. Patrimonio cultural prehispánico y peligro geodinámico en el valle del Huatanay - Cusco

    Directory of Open Access Journals (Sweden)

    2005-01-01

    Full Text Available Patrimoine culturel pré-hispanique et aléa géodynamique dans la vallée du Huatanay, Cusco Résumé: Parmi les nombreux sites archéologiques pré-hispaniques de la vallée de Huatanay, Cusco, plusieurs sont menacés ou en train d’être détruits par des phénomènes de géodynamique externe (glissements de terrain, éboulements, alluvions torrentielles, karstification et érosion. La plupart de ces processus ont une dynamique lente, mais plusieurs d’entre eux montrent des signes d’accélération, due à leur dynamique propre ou sont aggravés par des interventions humaines : le manque de maintenance, la déprédation, les activités agricoles et forestières inadéquates, l’urbanisation et le tourisme non contrôlés. De los numerosos conjuntos arqueológicos prehispánicos existentes en el valle del Huatanay, Cusco, varios se encuentran amenazados o están siendo destruidos por fenómenos de geodinámica externa (deslizamientos, derrumbes, lavas torrenciales y karstificación y erosión. La mayoría de estos procesos son de carácter lento, pero muchos muestran signos de aceleración debido a su dinámica natural o por intervenciones humanas: la falta de mantenimiento, la depredación, las actividades agropecuarias y forestales inapropiadas, la urbanización y el turismo no controlados Pre-hispanic archeological heritage and geodynamic hazard in the valley of Huatanay - Cuzco Abstract: Of the numerous Prehispanic archaeological complexes located in the Huatanay Valley Cusco, several are threatened or are being destroyed by external geodynamics phenomena (landslides, rock falls, lava flows, karstification and erosion. Most of these processes are slow, but many of them show signs of acceleration, due to their natural dynamics or by humain intervention: lack of maintenance, depredation, inappropriate agricultural and forestry activities, and uncontrolled urbanization and tourism.

  5. Stratigraphy and erosional landforms of layered deposits in Valles Marineris, Mars

    Science.gov (United States)

    Komatsu, G.; Geissler, P. E.; Strom, R. G.; Singer, R. B.

    1993-01-01

    Satellite imagery is used to identify stratigraphy and erosional landforms of 13 layered deposits in the Valles Marineris region of Mars (occurring, specifically, in Gangis, Juventae, Hebes, Ophir-Candor, Melas, and Capri-Eos Chasmata), based on albedo and erosional styles. Results of stratigraphic correlations show that the stratigraphy of layered deposits in the Hebes, Juventae, and Gangis Chasmata are not well correlated, indicating that at least these chasmata had isolated depositional environments resulting in different stratigraphic sequences. On the other hand, the layered deposits in Ophir-Candor and Melas Chasmata appear to have been connected in each chasma. Some of the layered deposits display complexities which indicate changes in space and time in the dominant source materials.

  6. Los contratos de producción en el noreste de México: El valle de Mexicali a fines de la década de los ochenta

    Directory of Open Access Journals (Sweden)

    Alejandra Stamatis Maldonado

    1993-01-01

    Full Text Available El objetivo del presente trabajo es analizar la presencia de contratos de producción entre los productores de hortalizas de exportación en el valle de Mexicali y el capital estadounidense. A partir de una caracterización de los productores de hortalizas en el valle de Mexicali, se describe la forma básica que asumen las relaciones de financiamiento y de comercialización con las compañías distribuidoras, y se analizan esas relaciones en el contexto de la producción de hortalizas de exportación en el noroeste de México

  7. Monitoreo de un sistema de secado de bagazo acoplado a una caldera en un ingenio de México Monitoring of a bagasse drying system attached to a boiler in a sugar mill in Mexico

    Directory of Open Access Journals (Sweden)

    Federico J. Franck Colombres

    Full Text Available Se evaluó el desempeño de un secador de bagazo diseñado por la Estación Experimental Agroindustrial Obispo Colombres, acoplado a una caldera bagacera convencional en un ingenio de México (caldera Nº 5. Para ello, se realizaron ensayos de mediciones y balances de materia y energía, para la caldera operando con el secador y sin él en funcionamiento. La caldera Nº 5, de una producción nominal de 60 t/h de vapor y una presión máxima de trabajo de 29 bar, cuando fue alimentada únicamente con bagazo húmedo pudo generar como máximo 33 t/h de vapor a 19 bar y 269ºC, con un rendimiento energético de 60,4% y un índice de generación de 1,6 kg de vapor/ kg de bagazo. Con la adición del secador, se logró secar 28,6 toneladas de bagazo de 50,2% a 30,4% de humedad. Aproximadamente un 72% de este bagazo presecado se mezcló con bagazo húmedo y se utilizó para alimentar la caldera, produciéndose así 58,4 t/h de vapor; es decir, 77% más de vapor que sin secador. El rendimiento energético del sistema caldera-secador fue de 73,6%, un 21,8% superior al de la caldera sin secador, mientras que el índice de generación fue de 2,0 kg de vapor/ kg de bagazo, 25% mayor que el de la caldera original. Este aumento en la producción de vapor permitió sacar de servicio a la caldera Nº 6, que producía aproximadamente 20 t/h de vapor, con un rendimiento similar al de la caldera Nº 5 sin secador. Estas mejoras dieron como resultado, un ahorro de energía de 45,4 MJ/h, aproximadamente un 18% respecto a la energía consumida por ambas calderas (Nº 5 y Nº 6 cuando no funcionaba el secador. Este ahorro equivale a 1103 l/h de "fuel oil", es decir, alrededor de 1,5 millones de dólares por zafra.A bagasse dryer designed by Estación Experimental Agroindustrial Obispo Colombres was attached to a conventional bagasse boiler (Boiler No. 5 in a sugar mill in Mexico for evaluation. Measurement tests and material and energy balances for the boiler operating

  8. Analysis of vector magnetic anomalies over the Bayonnaise Knoll caldera obtained from a deep-sea magnetic exploration by AUV

    Science.gov (United States)

    Sayanagi, K.; Isezaki, N.; Matsuo, J.; Harada, M.; Kasaya, T.

    2011-12-01

    Bayonnaise Knoll is a submarine caldera with an outer rim of 2.5-3 km and a floor of 840-920 m, which is located in the Izu-Ogasawara arc. A large hydrothermal deposit, Hakurei deposit, lies in the southeast part of the caldera. In the R/V Bosei-maru cruise, we observed three components of magnetic anomalies at depths of 400-570 m along SE-NW and WE tracks across the caldera. In the R/V Yokosuka YK10-17 cruise, we observed three components and total intensity of magnetic anomalies at altitudes of 60-100 m around the Hakurei deposit and at depth of 500 m above the caldera. The analysis of these data is now energetically pushed forward. A 3D gridded data set of the vector magnetic anomaly in the latter cruise was made by solving the Laplace's equation in the areas where observation data were not available, which is the unique procedure for analysis of the vector anomalies. Several magnetization solutions have been so far obtained by successive approximation and inversion methods. We will here present the measurement of the geomagnetic field and analysis of magnetization structure in Bayonnaise Knoll caldera. Note that this study has been supported by the Ministry of Education, Culture, Sports, Science & Technology (MEXT).

  9. Emplacement and erosive effects of the south Kasei Valles lava on Mars

    Science.gov (United States)

    Dundas, Colin M.; Keszthelyi, Laszlo P.

    2014-01-01

    Although it has generally been accepted that the Martian outflow channels were carved by floods of water, observations of large channels on Venus and Mercury demonstrate that lava flows can cause substantial erosion. Recent observations of large lava flows within outflow channels on Mars have revived discussion of the hypothesis that the Martian channels are also produced by lava. An excellent example is found in south Kasei Valles (SKV), where the most recent major event was emplacement of a large lava flow. Calculations using high-resolution Digital Terrain Models (DTMs) demonstrate that this flow was locally turbulent, similar to a previously described flood lava flow in Athabasca Valles. The modeled peak local flux of approximately 106 m3 s−1 was approximately an order of magnitude lower than that in Athabasca, which may be due to distance from the vent. Fluxes close to 107 m3 s−1 are estimated in some reaches but these values are probably records of local surges caused by a dam-breach event within the flow. The SKV lava was locally erosive and likely caused significant (kilometer-scale) headwall retreat at several cataracts with tens to hundreds of meters of relief. However, in other places the net effect of the flow was unambiguously aggradational, and these are more representative of most of the flow. The larger outflow channels have lengths of thousands of kilometers and incision of a kilometer or more. Therefore, lava flows comparable to the SKV flow did not carve the major Martian outflow channels, although the SKV flow was among the largest and highest-flux lava flows known in the Solar System.

  10. Mineralogy, structural control and age of the Incachule Sb epithermal veins, the Cerro Aguas Calientes collapse caldera, Central Puna

    Science.gov (United States)

    Salado Paz, Natalia; Petrinovic, Iván; Do Campo, Margarita; Brod, José Affonso; Nieto, Fernando; da Silva Souza, Valmir; Wemmer, Klauss; Payrola, Patricio; Ventura, Roberto

    2018-03-01

    The Incachule Sb epithermal veins is located near to the N-E rim of the Cerro Aguas Calientes collapse caldera (17.5-10.8 Ma), in the geologic province of Puna, Salta- Argentina. It is hosted in Miocene felsic volcanic rocks with continental arc signature. The district includes twelve vein systems with mineralization of Sb occurring in hydrothermal breccias and stockwork. The veins are composed of quartz-sulfide with pyrite, stibnite and arsenopyrite. All around the veins, wall rocks are variably altered to clay minerals and sulfates in an area of around 2.5 km wide by more than 7 km long. The hydrothermal alterations recognized are: silicic, phyllic and argillic. The veins are characterized by high contents of Sb, As, and Tl and intermediate contents of Pb-Zn-Cu, and traces of Ag and Au. Homogenization and ice-melting temperatures of fluid inclusions vary from 125 °C to 189 °C and -2.4 °C to -0.8 °C. The isotopic data indicated a range of δ34S -3.04‰ to +0.72‰ consistent with a magmatic source for sulfur. We present the firsts K-Ar ages for hydrothermal illite/smectite mixed layers (I/SR1, 60% illite layers) and illite that constrain the age of the ore deposit (8.5-6.7 ± 0.2 Ma). The data shown here, let characterized the Incachule district as a shallow low sulfidation epithermal system hosted in a collapse caldera. Our data also indicate that mineralization is structurally controlled by a fault system related to the 10.3 Ma collapse of Aguas Calientes caldera. The interpreted local stress field is consistent with the regional one.

  11. Exportaciones del Valle del Cauca. Determinantes, comportamiento y prospectiva

    Directory of Open Access Journals (Sweden)

    Dubán F. Peña Benítez

    2007-01-01

    Full Text Available Este trabajo centra su análisis en los determinantes de las exportaciones del Valle del Cauca en el periodo 1970 - 2004 y, en una predicción de corto y mediano plazo a través de un VAR y una función generalizada de impulso respuesta. Los hallazgos mostraron significancía de variables como el ingreso mundial (IM, el precio de los bienes exportables (TCR, los acuerdos comerciales (Aptdea y la dinámica de la oferta exportable (XV-1. La predicción para las exportaciones de la región estableció que la TCR tiene efectos positivos en el corto plazo, el ingreso mundial (IM impacta de forma positiva más en el largo que en el corto plazo y la variable acuerdos comerciales muestra importancia sólo de corto mas no de largo plazo.

  12. Storage, Ascent, and Release of Silicic Magma in Caldera-forming Eruptions

    Science.gov (United States)

    Myers, Madison Logan

    The mechanisms and timescales associated with the triggering of caldera-forming eruptions remain ambiguous and poorly constrained. Do such eruptions start vigorously, then escalate, or can there be episodicity? Are they triggered through internal processes (e.g. recharge, buoyancy), or can external modulations play an important role? Key to answering these questions is the ability to reconstruct the state of the magma body immediately prior to eruption. My dissertation research seeks to answer these questions through detailed investigation of four voluminous caldera-forming eruptions: (1) 650 km3, 0.767 Ma Bishop Tuff, Long Valley, (2) 530 km3, 25.4 ka Oruanui eruption, Taupo, (3) 2,500 km3, 2.08 Ma Huckleberry Ridge Tuff, Yellowstone and (4) 250 km3, 26.91 Ma Cebolla Creek Tuff, Colorado. The main techniques I applied integrated glass geochemistry (major, trace and volatile), diffusion modeling, and detailed field sampling. In chapters two, three, and four these methods are applied to the initial fall deposits of three supereruptions (Bishop, Oruanui and Huckleberry Ridge) that preserve field-evidence for different opening behaviors. These behaviors range from continuous deposition of fall deposits and ignimbrite (Bishop), to repetitive start/stop behavior, with time breaks between eruptive episodes on the order of weeks to months (Oruanui, Huckleberry Ridge). To reconstruct the timescales of opening activity and relate this to conduit processes, I used two methods that exploit diffusion of volatiles through minerals and melt, providing estimates for the rate at which magmas ascended to the surface. This knowledge is then integrated with the pre-eruptive configuration of the magma body, based on melt inclusion chemistry, to interpret what triggered these systems into unrest. Finally, in chapter five I take a different approach by integrating geochemical data for melt inclusions and phenocryst minerals to test whether the mechanism of heat and volatile recharge

  13. The 1996-2009 borehole dilatometer installations, operation, and maintenance at sites in Long Valley Caldera, CA

    Science.gov (United States)

    Myren, Glenn; Johnston, Malcolm; Mueller, Robert

    2011-01-01

    High seismicity levels with accelerating uplift (under the resurgent dome) in Long Valley caldera in the eastern Sierra Nevada from 1989 to 1997, triggered upgrades to dilational strainmeters and other instrumentation installed in the early 1980's following a series of magnitude 6 earthquakes. This included two additional high-resolution borehole strainmeters and replacement of the failed strainmeter at Devil's Postpile. The purpose of the borehole-monitoring network is to monitor crustal deformation and other geophysical parameters associated with volcanic intrusions and earthquakes in the Long Valley Caldera. Additional instrumentation was added at these sites to improve the capability of providing continuous monitoring of the magma source under the resurgent dome. Sites were selected in regions of hard crystalline rock, where the expected signals from magmatic activity were calculated to be a maximum and the probability of an earthquake of magnitude 4 or greater is large. For the most part, the dilatometers were installed near existing arrays of surface tiltmeters, seismometers, level line, and GPS arrays. At each site, attempts are made to separate tectonic and volcanic signals from known noise sources in each instrument type. Each of these sites was planned to be a multi-parameter monitoring site, which included measurements of 3-component seismic velocity and acceleration, borehole strain, tilt, pore pressure and magnetic field. Using seismicity, geophysical knowledge, geologic and topographic maps, and geologists recommendations, lists of preliminary sites were chosen. Additional requirements were access, and telemetry constraints. When the final site choice was made, a permit was obtained from the U.S. Forest Service. Following this selection process, two new borehole sites were installed on the north and south side of the Long Valley Caldera in June of 1999. One site was located near Big Spring Campground to the east of Crestview. The second site was

  14. The thermal regime in the resurgent dome of Long Valley Caldera, California: Inferences from precision temperature logs in deep wells

    Science.gov (United States)

    Hurwitz, S.; Farrar, C.D.; Williams, C.F.

    2010-01-01

    Long Valley Caldera in eastern California formed 0.76Ma ago in a cataclysmic eruption that resulted in the deposition of 600km3 of Bishop Tuff. The total current heat flow from the caldera floor is estimated to be ~290MW, and a geothermal power plant in Casa Diablo on the flanks of the resurgent dome (RD) generates ~40MWe. The RD in the center of the caldera was uplifted by ~80cm between 1980 and 1999 and was explained by most models as a response to magma intrusion into the shallow crust. This unrest has led to extensive research on geothermal resources and volcanic hazards in the caldera. Here we present results from precise, high-resolution, temperature-depth profiles in five deep boreholes (327-1,158m) on the RD to assess its thermal state, and more specifically 1) to provide bounds on the advective heat transport as a guide for future geothermal exploration, 2) to provide constraints on the occurrence of magma at shallow crustal depths, and 3) to provide a baseline for future transient thermal phenomena in response to large earthquakes, volcanic activity, or geothermal production. The temperature profiles display substantial non-linearity within each profile and variability between the different profiles. All profiles display significant temperature reversals with depth and temperature gradients <50??C/km at their bottom. The maximum temperature in the individual boreholes ranges between 124.7??C and 129.5??C and bottom hole temperatures range between 99.4??C and 129.5??C. The high-temperature units in the three Fumarole Valley boreholes are at the approximate same elevation as the high-temperature unit in borehole M-1 in Casa Diablo indicating lateral or sub-lateral hydrothermal flow through the resurgent dome. Small differences in temperature between measurements in consecutive years in three of the wells suggest slow cooling of the shallow hydrothermal flow system. By matching theoretical curves to segments of the measured temperature profiles, we calculate

  15. Imaging the complex geometry of a magma reservoir using FEM-based linear inverse modeling of InSAR data: application to Rabaul Caldera, Papua New Guinea

    Science.gov (United States)

    Ronchin, Erika; Masterlark, Timothy; Dawson, John; Saunders, Steve; Martì Molist, Joan

    2017-06-01

    We test an innovative inversion scheme using Green's functions from an array of pressure sources embedded in finite-element method (FEM) models to image, without assuming an a-priori geometry, the composite and complex shape of a volcano deformation source. We invert interferometric synthetic aperture radar (InSAR) data to estimate the pressurization and shape of the magma reservoir of Rabaul caldera, Papua New Guinea. The results image the extended shallow magmatic system responsible for a broad and long-term subsidence of the caldera between 2007 February and 2010 December. Elastic FEM solutions are integrated into the regularized linear inversion of InSAR data of volcano surface displacements in order to obtain a 3-D image of the source of deformation. The Green's function matrix is constructed from a library of forward line-of-sight displacement solutions for a grid of cubic elementary deformation sources. Each source is sequentially generated by removing the corresponding cubic elements from a common meshed domain and simulating the injection of a fluid mass flux into the cavity, which results in a pressurization and volumetric change of the fluid-filled cavity. The use of a single mesh for the generation of all FEM models avoids the computationally expensive process of non-linear inversion and remeshing a variable geometry domain. Without assuming an a-priori source geometry other than the configuration of the 3-D grid that generates the library of Green's functions, the geodetic data dictate the geometry of the magma reservoir as a 3-D distribution of pressure (or flux of magma) within the source array. The inversion of InSAR data of Rabaul caldera shows a distribution of interconnected sources forming an amorphous, shallow magmatic system elongated under two opposite sides of the caldera. The marginal areas at the sides of the imaged magmatic system are the possible feeding reservoirs of the ongoing Tavurvur volcano eruption of andesitic products on the

  16. Seismic and gravity signature of the Ischia Island Caldera (Italy)

    Science.gov (United States)

    Capuano, P.; de Matteis, R.; Russo, G.

    2009-04-01

    The Campania (Italy) coasts are characterized by the presence of several volcanoes. The island of Ischia, located at the northwestern end of the Gulf of Naples, belongs to the Neapolitan Volcanic District together with Phlegrean Fields and Vesuvius, having all these Pleistocene volcanoes erupted in historical times, and it is characterized by diffuse hydrothermal phenomena The island represents the emergent part of a more extensive volcanic area developed mainly westward of the island, with underwater volcanoes aligned along regional fault patterns. The activity of Ischia volcano is testified by the occurrence of eruptions in historical times, the presence of intense hydrothermal phenomena, and by seismic activity (e.g. the 1883 Casamicciola earthquake). Ischia is populated by about 50,000 inhabitants increasing, mainly in the summer, due to thriving tourism business, partially due to its active volcanic state. Hazard assessment at active, densely populated volcanoes is critically based on knowledge of the volcanoes past behavior and the definition of its present state. As a contribution to the definition of the present state of the Ischia island volcano, we obtain a model of the shallow crust using geophysical observables through seismic tomography and 3D gravity inversion. In particular we use travel times collected during the Serapis experiment on the island and its surroundings and free air anomaly. A new 3D gravity inversion procedure has been developed to take better into account the shape and the effects of topography approximating it by a triangular mesh. Below each triangle, a sequence of triangular prisms is built, the uppermost prism having the upper face coincident with the triangle following the topography. The inversion is performed searching for a regularized solution using the minimum norm stabilizer. The main results inferable from the 3D seismic and gravity images are the definition of the caldera rims hypothesize by many authors along the

  17. Caracterización de la aloinmunización eritrocitaria en el Hospital Universitario del Valle entre 2011 y 2013 / Characterization of Red Blood Cells Alloimmunization at Hospital Universitario del Valle between 2011 and 2013 / Caracterização de aloimunização eritrocitária no Hospital Universitário do Valle no período de 2011 a 2013

    Directory of Open Access Journals (Sweden)

    José Arnulfo Pérez-Carrillo, Esp. MD.

    2014-11-01

    Full Text Available Introducción: Las necesidades nacionales de sangre están parcialmente cubiertas. El uso de la sangre implica la detección e identificación de anticuerpos inesperados en los receptores de componentes eritrocitarios. Objetivo: Caracterizar demográfica y clínicamente los casos de aloinmunización eritrocitaria en el servicio transfusional del Hospital Universitario del Valle (HUV, Cali, Valle del Cauca, Colombia entre 2011 y 2013. Metodología: Se diseñó un estudio de corte transversal con los casos de aloinmunización eritrocitaria transfundidos por el servicio transfusional del HUV entre el 1 de agosto del 2011 hasta el 31 de julio del 2013. Los casos se incluyeron a través de un muestreo con asignación al azar sistemático. Para ingreso de datos y análisis se empleó el programa Epi-Info para Windows®. El estudio contó con aprobación del Comité de Ética. Resultados: Se incluyeron 80 casos de los cuales el 53.8% eran de género femenino y el 46.2% masculino. Además, el 65% correspondía a raza mestiza hispana y el 35% a afrodescendientes. El 22.5% tenía antecedentes de enfermedades hematopoyéticas y el 45% estaban hospitalizados por diagnósticos incluidos en esta categoría del CIE-10. El 79% de las mujeres tenían historia obstétrica. El 18.75% fueron transfundidos previamente. El 36% de los casos contaba con un fenotipo CceeK. El 31.25% tenían aloanticuerpo Anti-E, seguido por Anti-K con el 21.25%. Conclusiones: El principal aloanticuerpo identificado fue Anti-E seguido de Anti-K. Asimismo existe un grupo importante de pacientes en los cuales no se pudo identificar el aloanticuerpo asociado, debido principalmente a mezcla de anticuerpos. Además, la mayoría de los casos corresponde a adultos jóvenes y adultos. En relación con las características clínicas de la muestra se observó una representación discreta de las hemoglobinopatías congénitas y la mayoría no fueron politransfundidos previamente. [Pérez JA, Cort

  18. Channel geometry and discharge estimates for Dao and Niger Valles, Mars

    Science.gov (United States)

    Musiol, S.; van Gasselt, S.; Neukum, G.

    2008-09-01

    Introduction The outflow channels Dao and Niger Valles are located at the eastern rim of the 2000-km diameter Hellas Planitia impact basin, in a transition zone with ancient cratered terrain and the volcanoes Hadriaca and Tyrrhena Patera (Hesperia Planum) on the one hand and fluvial, mass-wasting and aeolian deposits on the other hand [1]. Dao and Niger have alcove-shaped source regions similar to the chaotic terrains found in the Margaritifer Terra region, with flat floors, landslide morphologies and small, chaotically distributed isolated mounds. As [2] pointed out, the intrusion of volcanic material could be responsible for the release of pressurized water that can carry loose material away. This process could than have created a depression and an associated outflow channel. In contrast to [2] who made their calculations for Aromatum Chaos and Ravi Vallis, we have focused on Dao and Niger Valles for investigation, since they are spatially related to the nearby Hadriaca Patera. Heat-triggered outflow events seem likely. We follow the generally accepted assumption that water was the main erosional agent [3]. Furthermore we take into account that multiple floods with different volumes are more likely than a single event because of repressurization of an aquifer [4]. Background Hadriaca Patera Hadriaca Patera is among the oldest central-vent volcanoes on Mars, a low-relief volcano with a central caldera complex which consists predominantly of pyroclastic material. The erosional structure of degraded valleys on its flanks is indicative of dissection by a combination of groundwater sapping and surface runoff, attributed to a hydromagmatic eruption scenario [5]. Dao Vallis Dao Vallis is interpreted as collapse region of volcanic and sedimentary plains that have been eroded by surface and subsurface flow [5]. The approximately radial alignment to Hellas is interpreted as following deep-seated structural weakness zones generated by the impact. Small grabens and fractures

  19. The marine digital terrain model of the Panarea caldera (Aeolian Islands, Southern Italy

    Directory of Open Access Journals (Sweden)

    M. Anzidei

    1998-06-01

    Full Text Available A Marine Digital Elevation Model (MDEM of the still active volcanic area of Panarea caldera is presented in this paper. A fast and accurate survey was performed by means of the Differential Global Positioning System (DGPS geodetic technique coupled with an echo-sounding gear and a real time navigation software. The instrumentation was installed on board of a low draught boat in order to collect data starting from the bathymeter of one meter. Planar positions and depths were obtained with average accuracies of 30 cm and 10 cm respectively providing a 3D map of the seafloor useful for geomorphological, geophysical and volcanic hazard applications.

  20. El olvido de los silencios negros en el valle del Risaralda 1880-1973

    OpenAIRE

    Victoria Mena, Carlos Alfonso

    2014-01-01

    Los procesos de poblamiento y colonización en la cuenca media del valle geográfico del río Cauca, desde el siglo XVIII hasta finales del siglo XIX, dan cuenta de varios fenómenos de los que se debe ocupar la historiografía para desarrollar hipótesis asociadas a tipologías de frontera, como la cimarrona, que de algunas manera se pueden interpretar como rasgos de la configuración de hegemonías comunales y, por tanto, interpelar los enfoques que le otorgan a la colonización antioqueña un carácte...

  1. Recolección y procesamiento de basura en el Valle de El Guarco.

    OpenAIRE

    Quesada, Hilda; Mora, Benjamín; Hernández, Enrique; Arnáez, Elizabeth; Valverde, Virginia

    2016-01-01

    En 1987 se realizó un Diagnóstico Socio-ambiental en el Valle de El Guarco, con el propósito de conocer la magnitud y las características de los problemas ambientales en los cantones Central, Paraíso, Oreamuno y El Guarco de la provincia de Cartago y en el que el problema de la basura fue un aspecto por estudiar. La información se recopiló por medio del análisis de estudios realizados, entrevistas a miembros de los gobiernos locales y grupos de base así como giras de inspección ocular y aplic...

  2. Geothermal wells: a forecast of drilling activity

    Energy Technology Data Exchange (ETDEWEB)

    Brown, G.L.; Mansure, A.J.; Miewald, J.N.

    1981-07-01

    Numbers and problems for geothermal wells expected to be drilled in the United States between 1981 and 2000 AD are forecasted. The 3800 wells forecasted for major electric power projects (totaling 6 GWe of capacity) are categorized by type (production, etc.), and by location (The Geysers, etc.). 6000 wells are forecasted for direct heat projects (totaling 0.02 Quads per year). Equations are developed for forecasting the number of wells, and data is presented. Drilling and completion problems in The Geysers, The Imperial Valley, Roosevelt Hot Springs, the Valles Caldera, northern Nevada, Klamath Falls, Reno, Alaska, and Pagosa Springs are discussed. Likely areas for near term direct heat projects are identified.

  3. Magnetotelluric survey of Ischia resurgent caldera (Southern Italy): inference for volcano-tectonics and dynamic

    Science.gov (United States)

    Carlino, S.; Di Giuseppe, M. G.; Troiano, A.

    2017-12-01

    The island of Ischia (located in the Bay of Naples) represents a peculiar case of well-exposed caldera that has experienced a large (>800m) and rapid resurgence, until recent time. It gives us the possibility for a better understanding of caldera resurgence process, by integrating the available geological information with new geophysical data of the deeper structures associated to the resurgence. To this aim, a magnetotelluric survey of the island, has been performed along two main profiles of the central-western sector, obtaining the first electrical resistivity map down to a depth of 3km. The resurgence is tough to be associated to a shallow magma intrusion, which also produced a vigorous hot fluids circulation with high geothermal gradients (>150°Ckm-1) in the southern and western sector. The interpretation of resistivity variations allow us to recognize the main volcano-tectonic features of central-western part of the island, along the two profiles, such as the presence of a possible very shallow magmatic intrusion to a depth of about 1km, the tectonic structures bordering the resurgent area and the occurrence of large thermal anomaly of the western sector. All these data are fundamental for the assessment of volcano-dynamic of the island and associated hazard. Furthermore, this study show a not common example of a large resurgence that is likely generated by a laccolith intrusion. This process is generally associated to the arrival of fresh magma into the system that, in turn, may imply imminent eruption and high volcanic hazard.

  4. Mechanical and geometric controls on the structural evolution of pit crater and caldera subsidence

    Science.gov (United States)

    Holohan, E. P.; SchöPfer, M. P. J.; Walsh, J. J.

    2011-07-01

    Pit craters and calderas are volcanic depressions produced by subsidence of a magma reservoir roof. To identify how geometric and mechanical factors may influence the structural evolution of this subsidence, we used two-dimensional distinct element method numerical models. The reservoir host rock was represented as an assemblage of bonded circular particles that interact according to elastic-frictional laws. Varying particle and bond properties produced a range of bulk material properties characteristic of natural rock masses. Fracturing results when bonds break, once their shear or tensile strength is exceeded. The magma reservoir was represented as a region of nonbonded low-friction particles. Withdrawal of magma was simulated by incrementally reducing the area of the reservoir particles. Resultant gravity-driven failure and subsidence of the reservoir roof were explicitly replicated. Interaction of the roof's strength, Young's modulus, thickness/diameter ratio (T/D), and the reservoir's shape yields a variety of model structures and subsidence styles. In conceptual terms, four end-member subsidence styles developed: (1) "central sagging" favored by low strength and low T/D; (2) "central snapping" favored by high strength, low T/D, and a sill-like reservoir shape; (3) "single central block" favored by low to intermediate strength, high Young's modulus, and intermediate T/D; and (4) "multiple central blocks" favored by high strength, low Young's modulus, and high T/D. Most model realizations incorporated some combination of each style, however. The models provide a geomechanical framework for understanding natural pit crater or caldera structures, as at Nindiri (Nicaragua), Fernandina (Galapagos), Dolomieu (La Reunion), and Miyakejima (Japan).

  5. Shallow magnetic inclinations in the Cretaceous Valle Group, Baja California: remagnetization, compaction, or terrane translation?

    Science.gov (United States)

    Smith, Douglas P.; Busby, Cathy J.

    1993-10-01

    Paleomagnetic data from Albian to Turonian sedimentary rocks on Cedros Island, Mexico (28.2° N, 115.2° W) support the interpretation that Cretaceous rocks of western Baja California have moved farther northward than the 3° of latitude assignable to Neogene oblique rifting in the Gulf of California. Averaged Cretaceous paleomagnetic results from Cedros Island support 20 ± 10° of northward displacement and 14 ± 7° of clockwise rotation with respect to cratonic North America. Positive field stability tests from the Vizcaino terrane substantiate a mid-Cretaceous age for the high-temperature characteristic remanent magnetization in mid-Cretaceous strata. Therefore coincidence of characteristic magnetization directions and the expected Quaternary axial dipole direction is not due to post mid-Cretaceous remagnetization. A slump test performed on internally coherent, intrabasinal slump blocks within a paleontologically dated olistostrome demonstrates a mid-Cretaceous age of magnetization in the Valle Group. The in situ high-temperature natural remanent magnetization directions markedly diverge from the expected Quaternary axial dipole, indicating that the characteristic, high-temperature magnetization was acquired prior to intrabasinal slumping. Early acquisition of the characteristic magnetization is also supported by a regional attitude test involving three localities in coherent mid-Cretaceous Valle Group strata. Paleomagnetic inclinations in mudstone are not different from those in sandstone, indicating that burial compaction did not bias the results toward shallow inclinations in the Vizcaino terrane.

  6. Discontinuous drainage systems formed by highland precipitation and ground-water outflow in the Navua Valles and southwest Hadriacus Mons regions, Mars

    Science.gov (United States)

    Hargitai, H. I.; Gulick, V. C.; Glines, N. H.

    2017-09-01

    The Navua Valles are systems of paleodrainages located north of Dao Vallis, which empty into Hellas Planitia, the largest impact basin on Mars. In this study, we mapped and characterized the Navua Valles Region's individual drainage systems, including drainages along the southwestern flank of Hadriacus Mons, and one valley network from the same source as Navua Valles but flowing in the opposite direction. The major drainage systems share morphological characteristics common to both outflow channels and valley networks. The slopes in this region are dissected by two major Navua drainage systems (here Navua A* and B*) and several shorter, sub-parallel valleys formed on the highest gradient (approximately 20 m/km [1.15°]) slopes, at the lowest part of Hellas Basin's rim. The two major drainage systems originate in the highlands, and empty into the basin. Our mapping suggests that water in Navua Valles reached the basin floor in a complicated descent and included several episodes of surface ponding, surface runoff, infiltration, subsurface flow and subsequent outflow. The most prominent channel system, Navua A, forms a repetitive sequence of deep incision into bedrock, followed by a transition into broad channels in erodible materials, and then into unconfined deposits. This successive erosion-transport-deposition sequence continues to repeat along the valley's entire length forming a discontinuous pattern that is consistent with classical fluvial process models. The channels cut into volcanic plains likely emplaced from the formation of Tyrrhenus and Hadriacus Montes. The dendritic source valleys of Navua A originate from the rim of a highland crater while the rest of this subsystem consists of a single, discontinuous channel which is consistent with a single water source zone that likely supplied water for all channels downslope. These drainages may have formed as discontinuous channels, revealing the potential existence of subsurface drainage pathways located

  7. A probability tomography approach to the analysis of potential field data in the Campi Flegrei caldera (Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Iuliano, T.; Patella, D. [Naples Univ. Federico 2., Naples (Italy). Dipartimento di Scienze Fisiche; Mauriello, P. [Consiglio Nazionale delle Ricerche, Istituto per le Tecnologie Applicate ai Beni Culturali, Rome (Italy)

    2001-04-01

    The results of the application of the 3a probability tomography imaging approach to the study of the Ca mpi Fagarol (Cf) caldera are presented and discussed. The tomography approach has been applied to gravity, magnetic and ground deformation data already available in literature. The analysis of the 3a tomographic images is preceded by a brief qualitative interpretation of the original survey maps and by an outline of the probability tomography approach for each geophysical prospecting method. The results derived from the 3a tomographic images are the high occurrence probabilities of both gravity and ground deformation source centers in the Cf caldera under the town of Palazzo. A Bagger negative anomaly source centre is highlighted in the depth range 1.6-2 km b.s.l., whereas a positive ground deformation point source, responsible for the bradyseismic crisis of 1982-1984, is estimated at a mean depth of 3-4 km b.s.l. These inferences, combined with the results of a previous analysis of magnetotelluric, dipolar geolectrical and self-potential data, corroborate the hypothesis that the bradyseismic events in the CF area may be explained by hot fluids vertical advection and subsequent lateral diffusion within a trapped reservoir overlying a magma chamber.

  8. A probability tomography approach to the analysis of potential field data in the Campi Flegrei caldera (Italy

    Directory of Open Access Journals (Sweden)

    D. Patella

    2001-06-01

    Full Text Available The results of the application of the 3D probability tomography imaging approach to the study of the Campi Flegrei (CF caldera are presented and discussed. The tomography approach has been applied to gravity, magnetic and ground deformation data already available in literature. The analysis of the 3D tomographic images is preceded by a brief qualitative interpretation of the original survey maps and by an outline of the probability tomography approach for each geophysical prospecting method. The results derived from the 3D tomographic images are the high occurrence probabilities of both gravity and ground deformation source centres in the CF caldera under the town of Pozzuoli. A Bouguer negative anomaly source centre is highlighted in the depth range 1.6-2 km b.s.l., whereas a positive ground deformation point source, responsible for the bradyseismic crisis of 1982-1984, is estimated at a mean depth of 3-4 km b.s.l. These inferences, combined with the results of a previous analysis of magnetotelluric, dipolar geoelectrical and self-potential data, corroborate the hypothesis that the bradyseismic events in the CF area may be explained by hot fluids vertical advection and subsequent lateral diffusion within a trapped reservoir overlying a magma chamber.

  9. Volcanic calderas delineate biogeographic provinces among Yellowstone thermophiles.

    Science.gov (United States)

    Takacs-Vesbach, Cristina; Mitchell, Kendra; Jackson-Weaver, Olan; Reysenbach, Anna-Louise

    2008-07-01

    It has been suggested that the distribution of microorganisms should be cosmopolitan because of their enormous capacity for dispersal. However, recent studies have revealed that geographically isolated microbial populations do exist. Geographic distance as a barrier to dispersal is most often invoked to explain these distributions. Here we show that unique and diverse sequences of the bacterial genus Sulfurihydrogenibium exist in Yellowstone thermal springs, indicating that these sites are geographically isolated. Although there was no correlation with geographic distance or the associated geochemistry of the springs, there was a strong historical signal. We found that the Yellowstone calderas, remnants of prehistoric volcanic eruptions, delineate biogeographical provinces for the Sulfurihydrogenibium within Yellowstone (chi(2): 9.7, P = 0.002). The pattern of distribution that we have detected suggests that major geological events in the past 2 million years explain more of the variation in sequence diversity in this system than do contemporary factors such as habitat or geographic distance. These findings highlight the importance of historical legacies in determining contemporary microbial distributions and suggest that the same factors that determine the biogeography of macroorganisms are also evident among bacteria.

  10. Stress field control during large caldera-forming eruptions

    Directory of Open Access Journals (Sweden)

    Antonio Costa

    2016-10-01

    Full Text Available Crustal stress field can have a significant influence on the way magma is channelled through the crust and erupted explosively at the surface. Large Caldera Forming Eruptions (LCFEs can erupt hundreds to thousands of cubic kilometres of magma in a relatively short time along fissures under the control of a far-field extensional stress. The associated eruption intensities are estimated in the range 109 - 1011 kg/s. We analyse syn-eruptive dynamics of LCFEs, by simulating numerically explosive flow of magma through a shallow dyke conduit connected to a magma chamber that in turn is fed by a deeper magma reservoir, both under the action of an extensional far-field stress. Results indicate that huge amounts of high viscosity silicic magma can be erupted over timescales of a few to several hours. Our study provides answers to outstanding questions relating to the intensity and duration of catastrophic volcanic eruptions in the past. In addition, it presents far-reaching implications for the understanding of dynamics and intensity of large-magnitude volcanic eruptions on Earth and to highlight the necessity of a future research to advance our knowledge of these rare catastrophic events.

  11. Explosive eruptive history of Pantelleria, Italy: Repeated caldera collapse and ignimbrite emplacement at a peralkaline volcano

    Science.gov (United States)

    Jordan, Nina J.; Rotolo, Silvio G.; Williams, Rebecca; Speranza, Fabio; McIntosh, William C.; Branney, Michael J.; Scaillet, Stéphane

    2018-01-01

    A new, pre-Green Tuff (46 ka) volcanic stratigraphy is presented for the peralkaline Pantelleria Volcano, Italy. New 40Ar/39Ar and paleomagnetic data are combined with detailed field studies to develop a comprehensive stratigraphic reconstruction of the island. We find that the pre-46 ka succession is characterised by eight silica-rich peralkaline (trachyte to pantellerite) ignimbrites, many of which blanketed the entire island. The ignimbrites are typically welded to rheomorphic, and are commonly associated with lithic breccias and/or pumice deposits. They record sustained radial pyroclastic density currents fed by low pyroclastic fountains. The onset of ignimbrite emplacement is typically preceded (more rarely followed) by pumice fallout with limited dispersal, and some eruptions lack any associated pumice fall deposit, suggesting the absence of tall eruption columns. Particular attention is given to the correlation of well-developed lithic breccias in the ignimbrites, interpreted as probable tracers of caldera collapses. They record as many as five caldera collapse events, in contrast to the two events reported to date. Inter-ignimbrite periods are characterised by explosive and effusive eruptions with limited dispersal, such as small pumice cones, as well as pedogenesis. These periods have similar characteristics as the current post-Green Tuff activity on the island, and, while not imminent, it is reasonable to postulate the occurrence of another ignimbrite-forming eruption sometime in the future.

  12. Modificaciones en las calderas igneotubulares cubanas // Modifications in the Cuban boilers of fire tube

    Directory of Open Access Journals (Sweden)

    I. Pérez Mallea

    1998-01-01

    Full Text Available El objetivo de este trabajo es optimizar y diseñar las calderas igneotubulares nacionales, incluyendo las de inversión de llama yagua caliente. Con este fin se creo un software como soporte científico técnico que permite realizar los diferentes cálculosverificativos a través de los cuales se optimiza._________________________________________________________________________Abstract .The objective of this work is the optimizing and designing of the Cuban boilers of fire tube, including those of inverting offlame and hot water. A software have been developed as technical scientific supper for different calculations and optimizingprocess.

  13. Graben structure in the Las Cañadas edifice (Tenerife, Canary Islands): implications for active degassing and insights on the caldera formation

    Science.gov (United States)

    Galindo, Inés; Soriano, Carles; Martí, Joan; Pérez, Nemesio

    2005-06-01

    A graben structure has been identified at the western area of the Las Cañadas caldera wall, here referred as the Los Azulejos Graben. This graben is 1 km wide and is bounded by two major normal faults trending NE-SW, the Los Azulejos Fault and the Ucanca Fault. The graben was active for at least 0.5 Ma, from the end of the Ucanca Fm to the end of the Guajara Fm, and before the collapse of the Las Cañadas edifice that formed the western caldera. A right-lateral transtension regime operated in the graben as suggested by small fault orientations and kinematics. The prolongation of the NE rift zone of Tenerife to the Cañadas edifice is the most likely volcano-tectonic scenario for the graben. In this context, inflation of phonolitic shallow magma chambers may have produced reverse faults and reactivation of normal faults. An intense and widespread hydrothermal alteration, here called Azulejos-type, occurred mainly before the graben formation, while a fault-related hydrothermal alteration occurred during and after the graben. Diffuse carbon dioxide and hydrogen degassing in and around the Las Cañadas caldera show relatively enriched values along a NE-SW trend suggesting that faults in the Los Azulejos Graben act as a pathway for deep-seated gases to the surface. Diffuse degassing and hydrothermalism indicate that the graben area has been a zone of intense fluid circulation during the evolution of the Las Cañadas edifice.

  14. Factores que impiden el crecimiento socio económico de la corporación de producción y comercialización agrícola porvenir Valle del Chota en la comunidad de Chota cantón Ibarra; Diseño de un modelo administrativo financiero-contable para la corporación de producción y comercialización ''Porvenir Valle del Chota'', en el 2014.

    OpenAIRE

    Espinel Ponce, Edison Wilman

    2015-01-01

    Determinar la situación administrativa y financiera actual de la ''Corporación de Producción y Comercialización Agrícola Porvenir Valle del Chota'' con la finalidad de conocer y comprender el funcionamiento de la Corporación. Diseñar un modelo administrativo financiero, con políticas y procedimientos acorde a los requerimientos de la Corporación de Producción y Comercialización Agrícola ''Porvenir Valle del Chota'', con la finalidad de apoyar su desarrollo. El presente trabajo busca det...

  15. Tourism Development Based on Geopark in Bakkara Caldera Toba, Indonesia

    Science.gov (United States)

    Ginting, N.; Vinky Rahman, N.; Sembiring, G.

    2017-03-01

    Bakkara Caldera Toba is an outstanding product of natural phenomena of Toba Supervolcano which has fascinating nature and culture. Bakkara has a great potential to develop world tourism further. It requires a model of sustainable planning Geopark to develop Bakkara. This sustainable concept helps to improve the local community and tourist’s quality of life and also still maintain the quality of the environment. through field observation and depth interview. The Collected data with a triangulation method. Development tourism destination such as attractions and environment; facilities and services; accessibility; image; and price to consume. It associated based on Geopark aspects there are; geological heritage; geo-conservation activities; sustainable tourism activities; educational; activities; community involvement products; strong management structure; and secure basis, infrastructure, and activities. The results of this study indicate that the Bakkara has the potential to become a tourist destination by applying the concept of Geotourism which accentuate its natural side, by optimizing the management of its destination attractions, its facilities and services, and its accessibilities.

  16. La infección de cangrejos procedentes del valle de Condebamba (Cajamarca por metacercarias de Paragonimus

    Directory of Open Access Journals (Sweden)

    Manuel Tantaleán V.

    2014-06-01

    Full Text Available En los meses de febrero y julio de 1973 se colectaron cangrejos del Valle de Condebamba (Cajamarca correspondientes a Pseudothelphusa chilensis, 69 de ellos (34 machos y 35 hembras fueron examinados, buscando metacercarias de Paragonimus; 22 (64.7% de los machos y 29 (28.85 % de las hembras resultaron infectados con metacercarias, o sea 52 (72.46% de los 69 cangrejos estaban infectados, esta cifra es coincidente con la obtenida por Cuba y cols. (1974.

  17. Geophysical modeling of Valle de Banderas graben and its structural relation to Bahia de Banderas, Mexico

    OpenAIRE

    Arzate, Jorge A.; Álvarez, Román; Yutsis, Vsevolod; Pacheco, Jesús; López-Loera, Héctor

    2006-01-01

    A gravimetric survey consisting of five lines and 483 stations, as well as a magnetotelluric (MT) survey consisting ofl 7 observation sites, were made in the Valle de Banderas region for the determination of the structural characteristics of the valley. Additionally, data from a previous aeromagnetic survey were analyzed to correlate them with our geophysical measurements. The gravimetric and MT models confirm that the valley corresponds to a graben structure with slumped blocks that vary fro...

  18. Dust Explosion Characteristics of Agglomerated 35 nm and 100 nm Aluminum Particles

    Directory of Open Access Journals (Sweden)

    Hong-Chun Wu

    2010-01-01

    Full Text Available In the experiment, nanoparticles of 35 nm Al and 100 nm Al powders, respectively, formed particles with average sizes of 161 nm and 167 nm in agglomeration. The characteristics of dust cloud explosions with the two powder sizes, 35 nm and 100 nm, revealed considerable differences, as shown here: (dp/dtmax-35 nm = 1254 bar/s, (dp/dtmax-100 nm = 1105 bar/s; Pmax-35 nm = 7.5 bar, Pmax-100 nm = 12.3 bar, and MEC-35 nm = 40 g/m3, MEC-100 nm = 50 g/m3. The reason of Pmax-35 nm value is smaller than Pmax-100 nm may be due to agglomeration. From an analysis of the explosive residue, the study found that nanoparticles of 35 nm Al powder became filamentous strands after an explosion, where most of 100 nm Al nanoparticles maintained a spherical structure, This may be because the initial melting temperature of 35 nm Al is 435.71°C, while that for 100 nm Al is 523.58°C, higher by 87.87°C. This study discovered that explosive property between the 35 nm Al and 100 nm Al powders after agglomeration were different.

  19. [Renal biopsy practice in Piedmont and Valle d'Aosta].

    Science.gov (United States)

    Manganaro, Marco; Nebiolo, Pier Eugenio; Rollino, Cristiana; Giacchino, Franca; Savoldi, Silvana; Besso, Luca; Colla, Loredana; Amore, Alessandro; Ferro, Michela; Marazzi, Federico; Chiarinotti, Doriana; Guarnieri, Andrea; Quaglia, Marco; Manes, Massimo; Vaccaro, Valentina; Marcuccio, Cristina; Licata, Carolina; Patti, Rosaria; Mariano, Filippo; Bongi, Anna Maria; Biamino, Ercole; Boschetti, Maria Antonietta; Della Volpe, Mario; Malcangi, Ugo; Baroni, Adriana; Vagelli, Giuseppe; Costantini, Luigia; Salomone, Mario; Formica, Marco; Caramello, Elisa; Campo, Andrea; Pignone, Eugenia; Messuerotti, Alessandra; Roccatello, Dario; Stratta, Piero; Segoloni, Giuseppe; Coppo, Rosanna

    2012-01-01

    In 2010 a questionnaire was administered to the renal units of Piedmont and Valle d'Aosta to analyze their procedures for renal biopsy (RB). Seventy-eight percent of units performed RBs, 57% for more than 20 years, but only 43% performed at least 20 BRs per year. 20/21 units performed RB in an inpatient setting and 1/21 in day hospital with the patient remaining under observation the night after. Thirty-two percent did not consider a single kidney as a contraindication to RB, 59% considered it a relative contraindication and 9% considered it an absolute contraindication. In 90.5% of units there was a specific protocol for patient preparation for RB and 86% used a specific informed consent form. Ninety-five percent of units performed ultrasound-guided RB, 60% of them using needle guides attached to the probe. In 81% of units the left side was preferred; 71% put a pillow under the patient's abdomen. All units used disposable, automated or semi-automated needles. Needle size was 16G in 29%, 18G in 58%, and both 16G and 18G in 14% of units; 1 to 3 samples were drawn. One third of units had a microscope available for immediate evaluation of specimen adequacy. After RB, 86% of units kept patients in the prone position for 2-6 hours and all prescribed a period of bed rest (at least 24 hours in 90.5%). 90.5% of units followed a specific postbiopsy observation protocol consisting of blood pressure, heart rate and red blood cell measurements at different times, and urine monitoring and ultrasound control within 12-24 hours (only half of them also employing color Doppler). One third of all units discharged patients after 1 day and two thirds after 2-3 days; all prescribed abstention from effort and from antiplatelet drugs for 7-15 days. In 9 units both RB and tissue processing and examination were done in the same hospital, while 12 units sent the samples elsewhere. 76% obtained results in 2-4 days, 19% in 6-7 days, and 5% in 10-15 days. Less than 20% of the interviewed

  20. Estudio clínico epidemiológico de bartonelosis humana en el valle del Monzón, Huamalíes, Huánuco

    Directory of Open Access Journals (Sweden)

    Abelardo Tejada

    2003-12-01

    Full Text Available OBJETIVO: Estudiar los casos de bartonelosis humana en valle del Monzón y determinar las especies de Lutzomyia que podrían jugar papel en la transmisión de la enfermedad en la zona. MATERIAL Y MÉTODOS: Se estudió casos de la enfermedad de Carrión en la selva alta del valle del Monzón, provincia de Huamalíes, Huánuco, donde entre 1997 y 1998 se presentó un brote epidémico. Para el diagnóstico de los casos se realizó frotis y gota gruesa, hemocultivo y serología. Para la captura de flebotominos, se utilizó trampas de luz CDC y trampa Shannon, en ambientes intra y peridomiciliarios. RESULTADOS: A lo largo de 21 localidades, la enfermedad afectó 140 personas, 25 de ellos entre 1 y 4 años de edad, 81 mujeres y 59 hombres; 121 presentaron la fase aguda de la enfermedad, 16 la fase intercalar y 3 la fase eruptiva. La población de la zona se dedica principalmente al cultivo de la coca, café y cacao. CONCLUSIÓN: Se estableció que el valle del Monzón es nueva zona endémica de bartonelosis humana, donde la transmisión ocurre principalmente en ambientes intra y peridomiciliarios, siendo Lutzomyia serrana el vector más probable.

  1. Prácticas ambientales de las empresas turísticas en valle de Bravo

    Directory of Open Access Journals (Sweden)

    Hernández Peñaloza1 Nadia

    2012-05-01

    Full Text Available El presente artículo analiza las prácticas ambientales de los actores sociales que se relacionan con las empresas turísticas del municipio de Valle de Bravo, Estado de México. Cabe mencionar que dichas prácticas se consideraron desde el punto de vista socio- económico, es decir, no sólo como se asumen en cuanto al manejo de los recursos naturales, sino también desde su entorno social y económico. Por ello, a partir de la propuesta metodológica de la teoría de sistemas complejos, se analizan los efectos producidos en los entornos de este destino turístico, lo que permite visualizar deuna manera holística la situación que prevalece para al cuidado del ambiente con la participación de todos los actores sociales de la localidad. Los resultados encontrados muestran una gran debilidaden la implementación de dichas prácticas, ya que éstas, actualmente, son impuestas por el gobierno municipal y no se asumen como una iniciativa de los propios actores que participan en las empresas turísticas. Por esta razón, las condiciones de deterioro ambiental en Valle de Bravo son cada vez mayores. A partir de los resultados generados por este estudio, se formulan recomendaciones de implementación y mejoramiento de las prácticas ambientales que contribuyen a la conservación y al cuidado del ambiente.

  2. Estudios sobre la enfermedad de Carrión en el valle interandino del Mantaro: II. Incidencia de la infección bartonelosica en la población humana

    Directory of Open Access Journals (Sweden)

    Arístides Herrer

    1960-01-01

    Full Text Available Con la finalidad de determinar la zona endémica de la verruga peruana o enfermedad de Carrión en el valle del Mantaro, durante la segunda quincena de abril. 1959, se realizaron 239 hemocultivos y una encuesta informativa en la población del mencionado valle. Para los cultivos se obtuvo 215 muestras de sangre en la población humana y, las 24 restantes, en algunos animales domésticos. En la encuesta se trató de recoger las informaciones que la gente de la región podría ofrecer acerca de la verruga, al mismo tiempo que todas las personas encuestadas fueron revisadas por los autores en busca del brote verrucoso. Los siguientes son los principales resultados obtenidos: 1. En los cultivos con sangre humana se obtuvo 5 positivos, 172 negativos y 38 contaminados y. en la de los animales domésticos, 13 negativos y 11 contaminados. Todos los hemocultivos positivos correspondieron a personas que habitan en localidades que se hallan entre 2.800 y 3,000 metros de altitud. 2. Dos de las cinco personas que ofrecieran hemocultivo positivo, al momento de extraérseles la sangre se encontraban en estado febril y con abundantes bartonelas en los eritrocitos circulantes; ambas murieron pocos días después. Las tres restantes no presentaban síntomas atribuibles a la enfermedad de Carrión, y dos de ellas fueron observadas durante los 15 meses subsiguientes sin que presentasen brote verrucoso. 3. En la encuesta se verificó que, con rarísimas excepciones, la gente del valle del Mantaro no conocía la verruga. Del mismo modo, tan sólo en dos ocasiones los autores observaron nódulos subcutáneos semejantes a verrucomas. 4. Se hace resaltar el que la enfermedad de Carrión sea endémica a considerable altitud en el valle del Mantaro, así como la rareza del brote cutáneo y se cuestiona la extrema gravedad que se atribuye a la verruga en el referido valle del Mantaro.

  3. Deformation regime and long-term precursors to eruption at large calderas: Rabaul, Papua New Guinea

    Science.gov (United States)

    Robertson, Robert M.; Kilburn, Christopher R. J.

    2016-03-01

    Eruptions at large calderas are normally preceded by variable rates of unrest that continue for decades or more. A classic example is the 1994 eruption of Rabaul caldera, in Papua New Guinea, which began after 23 years of surface uplift and volcano-tectonic (VT) seismicity at rates that changed unevenly with time by an order of magnitude. Although the VT event rate and uplift rate peaked in 1983-1985, eruptions only began a decade later and followed just 27 hours of anomalous changes in precursory signal. Here we argue that the entire 23 years of unrest belongs to a single sequence of damage accumulation in the crust and that, in 1991-1992, the crust's response to applied stress changed from quasi-elastic (elastic deformation with minor fault movement) to inelastic (deformation predominantly by fault movement alone). The change in behaviour yields limiting trends in the variation of VT event rate with deformation and can be quantified with a mean-field model for an elastic crust that contains a dispersed population of small faults. The results show that identifying the deformation regime for elastic-brittle crust provides new criteria for using precursory time series to evaluate the potential for eruption. They suggest that, in the quasi-elastic regime, short-term increases in rates of deformation and VT events are unreliable indicators of an imminent eruption, but that, in the inelastic regime, the precursory rates may follow hyperbolic increases with time and offer the promise of developing forecasts of eruption as much as months beforehand.

  4. Viscoelastic crustal deformation by magmatic intrusion: A case study in the Kutcharo caldera, eastern Hokkaido, Japan

    Science.gov (United States)

    Yamasaki, Tadashi; Kobayashi, Tomokazu; Wright, Tim J.; Fukahata, Yukitoshi

    2018-01-01

    Geodetic signals observed at volcanoes, particularly their temporal patterns, have required us to make the correlation between the surface displacement and magmatic process at depth in terms of viscoelastic crustal rheology. Here we use a parallelized 3-D finite element model to examine the response of the linear Maxwell viscoelastic crust and mantle to the inflation of a sill in order to show the characteristics of a long-term volcano deformation. In the model, an oblate-spheroidal sill is instantaneously or gradually inflated in a two-layered medium that consists of an elastic layer underlain by a viscoelastic layer. Our numerical experiments show that syn-inflation surface uplift is followed by post-inflation surface subsidence as the viscoelastic substrate relaxes. For gradual inflation events, the magnitude of inflation-induced uplift is reduced by the relaxation, through which the volume of a magma inferred by matching the prediction of an elastic model with observed surface uplift could be underestimated. For a given crustal viscosity, sill depth is the principal factor controlling subsidence caused by viscoelastic relaxation. The subsidence rate is highest when the inflation occurs at the boundary between the elastic and the viscoelastic layers. The mantle viscosity has an insignificant impact unless the depth of the inflation is greater than a half the crustal thickness. We apply the viscoelastic model to the interferometric synthetic aperture radar (InSAR) data in the Kutcharo caldera, eastern Hokkaido, Japan, where the surface has slowly subsided over a period of approximately three years following about a two-year period of inflation. The emplacement of a magmatic sill is constrained to occur at a depth of 4.5 km, which is significantly shallower than the geophysically imaged large-scale magma chamber. The geodetically detected deformation in the caldera reflects the small-scale emplacement of a magma that ascended from the deeper chamber, but not the

  5. La inserción al Asia-Pacífico, oportunidades y desafíos para el Valle del Cauca y la región pacífica colombiana

    Directory of Open Access Journals (Sweden)

    Ricardo Coutin

    2014-12-01

    Full Text Available Resumen: El objetivo general del texto es brindar una aproximación a los retos y las oportunidades que representa, para el Valle del Cauca y la Región Pacífica colombiana, la inserción al Asia-Pacífico. Para lo cual se plantean tres objetivos específicos: primero, analizar someramente el contexto económico comercial del Asia-Pacífico y América Latina, con especial énfasis en Colombia y los demás países de la Alianza del Pacífico (AP; segundo, estudiar las oportunidades y los retos para el Valle del Cauca y la Región Pacífica colombiana que plantea la puesta en escena del bloque comercial denominado Alianza del Pacífico; y tercero, indagar sobre los retos de competitividad y productividad que enfrenta el Valle del Cauca y que afectan el ambiente de negocios. El documento concluye que Colombia se encuentra rezagada en su inserción con la cuenca del Asia-Pacífico; también se plantea la necesidad de abordar el tema de estudio desde un enfoque subnacional.

  6. Native gold and gold-rich sulfide deposits in a submarine basaltic caldera, Higashi-Aogashima hydrothermal field, Izu-Ogasawara frontal arc, Japan

    Science.gov (United States)

    Iizasa, Kokichi; Asada, Akira; Mizuno, Katsunori; Katase, Fuyuki; Lee, Sangkyun; Kojima, Mitsuhiro; Ogawa, Nobuhiro

    2018-04-01

    Sulfide deposits with extremely high Au concentrations (up to 275 ppm; avg. 102 ppm, n = 15), high Au/Ag ratios (0.24, n = 15), and low Cu/(Cu + Zn) ratios (0.03, n = 15) were discovered in 2015 in active hydrothermal fields at a water depth of 760 m in a basalt-dominated submarine caldera in the Izu-Ogasawara frontal arc, Japan. Native gold grains occur in massive sulfide fragments, concretions, and metalliferous sediments from a sulfide mound (40 m across and 20 m high) with up to 30-m-high black smoker chimneys. Tiny native gold grains up to 14 μm in diameter are mainly present in sulfide fallouts from chimney orifices and plumes. Larger native gold grains up to 150 μm long occur mostly as discrete particles and/or with amorphous silica and sulfides. The larger gold grains are interpreted to represent direct precipitation from Au-bearing hydrothermal fluids circulating in and/or beneath the unconsolidated sulfide mound deposits. Sulfur isotope compositions from a limited number of sulfide separates (n = 4) range from 4.3 to 5.8‰ δ34S, similar to the quaternary volcanic rocks of the arc. Barite separates have values of 22.2 and 23.1‰, close to modern seawater values, and indicate probable seawater sulfate origin. The Cu, Zn, and Pb concentrations in bulk samples of sulfide-rich rocks are similar to those of volcanogenic massive sulfides formed in continental crustal environments. The gold is interpreted to have formed by low-temperature hydrothermal activity, perhaps genetically different from systems with documented magmatic contributions or from seafloor hydrothermal systems in other island arc settings. Its presence suggests that basalt-dominated submarine calderas situated on relatively thick continental crust in an intraoceanic arc setting such as the Higashi-Aogashima knoll caldera may be perspective for gold mineralization.

  7. Prevalence of school desertion during teenage pregnancy from public schools in Valle del Cauca, 2006

    OpenAIRE

    Iván Osorio; Mauricio Hernández

    2011-01-01

    Antecedentes: Partiendo de la institución educativa, se investigó la relación entre embarazo adolescente y deserción escolar y como influía el grado escolar y la edad de la embarazada en su riesgo de deserción. Materiales y métodos: Se aplicó una encuesta voluntaria en 180 instituciones educativas oficiales del departamento del Valle del Cauca, correspondiente a 112,470 estudiantes mujeres, encontrando 605 embarazadas. De estas, a 564 se les realizó una entrevista por un profesional en psicol...

  8. Definición del mercado de trigo cristalino en el valle del Yaqui, México

    OpenAIRE

    Garza Lagler, María Cristina; Taddei Bringas, Cristina

    2016-01-01

    Resumen: El valle del Yaqui es una región productora de trigo en el noroeste de México, cuyas agroempresas tienen una participación creciente en el mercado internacional. El objetivo de este trabajo es una aproximación a la definición del mercado del trigo cristalino que se produce en su territorio, para lo cual se realizó un análisis descriptivo apoyado en entrevistas a actores estratégicos del sistema de producción. Los resultados indican que este grano tiene tres mercados: la industria de ...

  9. La inserción al Asia-Pacífico, oportunidades y desafíos para el Valle del Cauca y la región pacífica colombiana

    OpenAIRE

    Countin, Ricardo

    2014-01-01

    El objetivo general del texto es brindar una aproximación a los retos y las oportunidades que representa, para el Valle del Cauca y la Región Pacífica colombiana, la inserción al Asia-Pacífico. Para lo cual se plantean tres objetivos específicos: primero, analizar someramente el contexto económico comercial del Asia-Pacífico y América Latina, con especial énfasis en Colombia y los demás países de la Alianza del Pacífico (AP); segundo, estudiar las oportunidades y los retos para el Valle del C...

  10. Secular Trends of Amyotrophic Lateral Sclerosis: The Piemonte and Valle d'Aosta Register.

    Science.gov (United States)

    Chiò, Adriano; Mora, Gabriele; Moglia, Cristina; Manera, Umberto; Canosa, Antonio; Cammarosano, Stefania; Ilardi, Antonio; Bertuzzo, Davide; Bersano, Enrica; Cugnasco, Paolo; Grassano, Maurizio; Pisano, Fabrizio; Mazzini, Letizia; Calvo, Andrea

    2017-09-01

    This study reports the long-term epidemiologic trends of amyotrophic lateral sclerosis (ALS) based on a prospective register. To examine the 20-year epidemiologic trends of ALS in the Piemonte and Valle d'Aosta regions of Italy. The Piemonte and Valle d'Aosta Register for ALS (PARALS) is an epidemiologic prospective register that covers 2 Italian regions (population of 4 476 931 inhabitants according to the 2011 census) from January 1, 1995, through December 31, 2014. Case ascertainment is based on multiple sources (neurologic departments, hospital discharge archives, and mortality records). Incidence rates are age and sex standardized for the Italian population of the 2011 census. Age-period-cohort (APC) analysis was performed using a Poisson regression model. The primary study outcomes were long-term incidence and prevalence rates of ALS using a prospective design and their determinants. During the study period, a total of 2702 patients (mean [SD] age at onset, 65.7 [11.1] years; 1246 [46.1%] female and 1456 [53.9%] male) received a diagnosis of ALS between 1995 and 2014, corresponding to a crude annual incidence rate of 3.03 per 100 000 population (95% CI, 2.85-3.23) and an adjusted incidence rate of 2.78 per 100 000 population (95% CI, 2.57-2.96). The age-adjusted incidence rate increased in the 2 decades of the study (1995-2004: 2.66; 95% CI, 2.50-2.83; 2005-2014: 2.89; 95% CI, 2.71-3.07; P = .04), mostly in women. The adjusted rate ratio of men to women decreased from 1.27:1 (1995-2004) to 1.17:1 (2005-2014). The analysis of deviance for the APC regression models indicated that the drift variable is relevant in explaining the variation of ALS incidence rates over time in the overall population (change in deviance, 4.6553; P = .03) and in women (change in deviance, 3.8821; P = .05) but not in men (change in deviance, 0.77215; P = .38). A total of 479 patients with ALS were alive and had not undergone tracheostomy at the prevalence day

  11. Església i poder comtal al territori d’Urgell. Guifré el Pilós i la reorganització de la Vall de Lord

    Directory of Open Access Journals (Sweden)

    Riu, Manuel

    1999-12-01

    Full Text Available This article shows how was "La Vall de Lord" organized in four castles, their respective territories and ten rural parish churches and also their evolution during the ninth and tenth centuries. It explains the exemption land taxes in the southern part of the Urgell's county and bishopric, and the relievant role of Guifred "el Pilos" count and Seu bishops in that establishment. Two bénédictine monasteries, Sant Llorenç de Morunys and Sant Pere de Graudescales, had an important development in the "Vail de Lord". At the first time, both were regular priests'canonicals.[fr] Dans cet article, on présente l'organisation de la Vallée de Lord en quatre chatellenies et dix paroisses, et leur évolution pendant les IXème et Xème siècles, en indiquant le statut de zone franche dans la limite méridionale du comté et évêché d'Urgell, et le rôle notoire du comte Guifred "el Pilos" et des prélats de La Seu. Dans la vallée prirent leur essor également deux monastères bénédictins, celui de Sant Llorenç de Morunys et celui de Sant Pere de Graudescales, qui furent initialement des chapitres de clercs réguliers.

  12. Evaluación de los programas de control prenatal para adolescentes en el valle de Aburrá, 2003 Evaluation of prenatal control programs offered to teenagers in Valle de Aburrá, Colombia, 2003

    Directory of Open Access Journals (Sweden)

    Carlos Adolfo Salazar

    2004-02-01

    Full Text Available Objetivo: la investigación que se presenta a continuación tuvo como objetivo identificar y evaluar los programas de control prenatal para adolescentes ofrecidos en el valle de Aburrá, Antioquia, Colombia, durante el año 2003. Materiales y métodos: se revisaron varias fuentes primarias y se elaboró un listado de todas las instituciones de salud del valle de Aburrá. Se hicieron entrevistas telefónicas con los respectivos directores para establecer cuáles instituciones tenían un programa de control prenatal exclusivo para adolescentes y a estas instituciones se les aplicó un formato de evaluación para determinar si cumplían con los estándares internacionales descritos en la literatura como esenciales en un programa de control prenatal para adolescentes. Resultados: sólo una de las 101 instituciones de salud que ofrecían control prenatal tenía un programa exclusivo para adolescentes. Sin embargo, a la luz de la evaluación, dicho programa no cumplía con los estándares de un programa de control prenatal para adolescentes. Conclusión: a pesar de que en Colombia el embarazo en adolescentes es un problema de salud pública, los programas de control prenatal para adolescentes no se han implementado en el valle de Aburrá. Establecerlos constituye una de las estrategias para resolver esta problemática. Objective : this investigation had the aim of identifying and evaluating the prenatal control programs offered to teenagers in the Aburrá Valley region of Colombia in 2003. Methodology: through various sources a list was compiled which included all the health institutions in the Aburrá Valley region. The institutions which offered exclusive teenage prenatal control were identified by telephone and a questionnaire was applied to them with the purpose of knowing if they met the international standards described in relevant sources as being essential in a teenage prenatal control program. Results: in only one of the 101 health

  13. Biodiversity of Thermophilic Prokaryotes with Hydrolytic Activities in Hot Springs of Uzon Caldera, Kamchatka (Russia)▿ †

    OpenAIRE

    Kublanov, Ilya V.; Perevalova, Anna A.; Slobodkina, Galina B.; Lebedinsky, Aleksander V.; Bidzhieva, Salima K.; Kolganova, Tatyana V.; Kaliberda, Elena N.; Rumsh, Lev D.; Haertlé, Thomas; Bonch-Osmolovskaya, Elizaveta A.

    2008-01-01

    Samples of water from the hot springs of Uzon Caldera with temperatures from 68 to 87°C and pHs of 4.1 to 7.0, supplemented with proteinaceous (albumin, casein, or α- or β-keratin) or carbohydrate (cellulose, carboxymethyl cellulose, chitin, or agarose) biological polymers, were filled with thermal water and incubated at the same sites, with the contents of the tubes freely accessible to the hydrothermal fluid. As a result, several enrichment cultures growing in situ on different polymeric su...

  14. Ground deformation at collapse calderas: influence of host rock lithology and reservoir multiplicity

    Energy Technology Data Exchange (ETDEWEB)

    Geyer, A; Gottsmann, J [Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queen' s Road, BS8 1RJ, Bristol (United Kingdom)], E-mail: A.GeverTraver@bristol.ac.uk

    2008-10-01

    A variety of source mechanisms have been proposed to account for observed caldera deformation. Here we present a systematic set of new results from numerical forward modelling using a Finite Element Method. which provides a link between measured ground deformation and the inaccessible deformation source. We simulate surface displacements due to pressure changes in a shallow oblate reservoir overlain by host rock with variable mechanical properties. We find that the amplitude and wavelength of resultant ground deformation is dependent on the distribution of mechanically stiff and soft lithologies and their relative distribution above a reservoir. In addition, we note an influence of layering on the critical ratio of horizontal over vertical displacements, a criterion employed to discriminate between different finite source geometries.

  15. Perspectiva bioenergética de los residuos sólidos urbanos en el Valle de Lerma

    OpenAIRE

    Manrique, Silvina Magdalena; Franco, Ada Judith; Núñez, Virgilio; Seghezzo, Lucas

    2017-01-01

    Los residuos sólidos urbanos (RSU), que tradicionalmente se han depositado a cielo abierto en el Valle de Lerma (Salta), podrían comenzar a ser dispuestos en un relleno sanitario regional en función de un proyecto provincial existente. El mencionado proyecto no incluye el aprovechamiento de la energía contenida en los RSU. En este trabajo se consideraron como recursos bioenergéticos potenciales. Dos clases de estimaciones fueron realizadas a partir de diferentes metodologías: a) poder caloríf...

  16. paleopatológico del antiguo Valle de Toluca, México

    Directory of Open Access Journals (Sweden)

    Héctor Favila Cisneros

    2008-01-01

    ciénega del Chignahuapan de la Cuenca del Alto Lerma, ahora cabecera municipal de Santa Cruz Atizapan, Estado de México, se desarrolló una sociedad isleña con un modo de vida lacustre, en la cual su equilibrio estaba determinado por la interrelación con el aprovechamiento de los recursos de la laguna y las difíciles condiciones del cenagal. El análisis morfoscópico realizado en las osamentas provenientes de los entierros del sitio arqueológico "La Campana Tepozoco" arrojó una serie de evidencias patológicas, que permiten conocer las condiciones generales de la salud de los habitantes del sitio. La presente investigación nos acerca al conocimiento de las diversas condiciones de existencia, donde el modo de vida impactó en la salud y nutrición de los miembros de esta población de la zona pantanosa de la antigua ciénega del Valle de Toluca.

  17. Chemical weathering of palaeosols from the Lower Palaeolithic site of Valle Giumentina, central Italy

    Science.gov (United States)

    Degeai, Jean-Philippe; Villa, Valentina; Chaussé, Christine; Pereira, Alison; Nomade, Sébastien; Aureli, Daniele; Pagli, Marina; Nicoud, Elisa

    2018-03-01

    The major archaeological site of Valle Giumentina (Abruzzo) contains a well-dated Lower Palaeolithic pedosedimentary sequence that provides an excellent opportunity to study the relationships among soil weathering, volcanism and climate change at the glacial/interglacial and submillennial timescales in central Italy and the Mediterranean area during the Middle Pleistocene, as well as the human-environment interactions of some of the earliest settlements in central southern Europe. High-resolution analyses of geochemistry and magnetic susceptibility revealed the presence of eleven palaeosols, ten of which (S2-S11) were formed between 560 and 450 ka based on 40Ar/39Ar dating of sanidine in tephras, i.e. spanning marine isotope stages (MIS) 14-12. The evolution of the major and trace element composition suggests that the palaeosols were mainly formed by in situ weathering of the parent material. The major phases of soil weathering occurred during the MIS 13 interglacial period (S8 and S6) as well as during episodes of rapid environmental change associated with millennial climatic oscillations during the MIS 14 and 12 glaciations (S11 and S2, respectively). Although global forcing such as orbital variations, solar radiation, and greenhouse gas concentrations may have influenced the pedogenic processes, the volcanism in central Italy, climate change in the central Mediterranean, and tectono-sedimentary evolution of the Valle Giumentina basin also impacted and triggered the formation of most palaeosols, which provided subsistence resources for the Lower Palaeolithic human communities. This study highlights the importance of having high-resolution palaeoenvironmental records with accurate chronology as close as possible to archaeological sites to study human-environment interactions.

  18. Dalla politica alla gestione del bene comune. L’esempio del teatro Valle a Roma

    Directory of Open Access Journals (Sweden)

    Alice Furlan

    2015-11-01

    Full Text Available The concept of common good could be declined in three major points: 1 the theft of the good itself from the profit mindset; 2 the creation of a link between the community and the good; 3 the creation of a new management form, neither public nor private, which knows the capacity of the good itself. From the analysis of the schedule published by MiBAC, it is clear that there is a lack of founds addressed to the artistic research. The situation that occurs nowadays is imposing the necessity of identifying another kind of development model. I took, as a research topic, Teatro Valle, which is one of the most important case in the Italian national context. The management of the entire structure undergoes through the principles of non-rivalry, non-exclusion and self-governance. The strongest points of this model are: the idea of an alternative management and the creation of synergies between several cultural movements.The theatre itself has been seeing as a multi-functional location: there are lots of performances flanked by debates, conferences, talks, and other initiatives. Another important aspect is the great visibility that the experience has been receiving through the years. However it is necessary to underline that the building, which is a private property, lives in a condition of lawlessness because it has been occupied. Moreover Teatro Valle has been accused of unfair competition by other cultural spaces. Since the culture is the common thread that helps us to uphold our identity, the common goods help us to recognize ourselves and state our fundamental rights.

  19. Los «verracos» del valle del Amblés (Ávila: del análisis espacial a la interpretación socio-económica

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    Álvarez Sanchís, Jesús R.

    1990-12-01

    Full Text Available Until recently, the zoomorphic sculpture of the West Meseta has been studied typologically, and therefore out of the cultural context in which it was produced. This paper is concerned with the zoomorphic sculpture in the Valle del Amblés (Ávila. We consider the sculptures as an index of economic value —cattle— and by studying their spatial distribution, we propose that they were used as landmarks or as delimiting critical resources —pasture— the explotation of which could have been organized by the elites of the Second Iron Age communities living in the valley.

    La escultura zoomorfa de la Meseta Occidental ha sido tradicionalmente estudiada en su dimensión tipológica y, en consecuencia, divorciada de la dinámica cultural que la produjo. Este trabajo, que tiene su marco geográfico en el Valle del Amblés (Ávila, considera las manifestaciones zoomorfas como el exponente de un valor productivo —la ganadería—; y, mediante el análisis de su distribución espacial, propone la hipótesis de considerarlas hitos o delimitadores de recursos críticos —pastos—, cuya explotación sería organizada por las élites de las comunidades de la II Edad del Hierro que poblaban el valle.

  20. Regional analysis of tertiary volcanic Calderas (western U.S.) using Landsat Thematic Mapper imagery

    Science.gov (United States)

    Spatz, David M.; Taranik, James V.

    1989-01-01

    The Landsat Thematic Mapper (TM) imagery of the Basin and Range province of southern Nevada was analyzed to identify and map volcanic rock assemblages at three Tertiary calderas. It was found that the longer-wavelength visible and the NIR TM Bands 3, 5, and 7 provide more effective lithologic discrimination than the shorter-wavelength bands, due partly to deeper penetration of the longer-wavelength bands, resulting in more lithologically driven radiances. Shorter-wavelength TM Bands 1 and 2 are affected more by surficial weathering products including desert varnish which may or may not provide an indirect link to lithologic identity. Guidelines for lithologic analysis of volcanic terrains using Landsat TM imagery are outlined.

  1. Fluid geochemistry and soil gas fluxes (CO2-CH4-H2S) at a promissory Hot Dry Rock Geothermal System: The Acoculco caldera, Mexico

    Science.gov (United States)

    Peiffer, L.; Bernard-Romero, R.; Mazot, A.; Taran, Y. A.; Guevara, M.; Santoyo, E.

    2014-09-01

    The Acoculco caldera has been recognized by the Mexican Federal Electricity Company (CFE) as a Hot Dry Rock Geothermal System (HDR) and could be a potential candidate for developing an Enhanced Geothermal System (EGS). Apart from hydrothermally altered rocks, geothermal manifestations within the Acoculco caldera are scarce. Close to ambient temperature bubbling springs and soil degassing are reported inside the caldera while a few springs discharge warm water on the periphery of the caldera. In this study, we infer the origin of fluids and we characterize for the first time the soil degassing dynamic. Chemical and isotopic (δ18O-δD) analyses of spring waters indicate a meteoric origin and the dissolution of CO2 and H2S gases, while gas chemical and isotopic compositions (N2/He, 3He/4He, 13C, 15N) reveal a magmatic contribution with both MORB- and arc-type signatures which could be explained by an extension regime created by local and regional fault systems. Gas geothermometry results are in agreement with temperature measured during well drilling (260 °C-300 °C). Absence of well-developed water reservoir at depth impedes re-equilibration of gases upon surface. A multi-gas flux survey including CO2, CH4 and H2S measurements was performed within the caldera. Using the graphical statistical analysis (GSA) approach, CO2 flux measurements were classified in two populations. Population A, representing 95% of measured fluxes is characterized by low values (mean: 18 g m- 2 day- 1) while the remaining 5% fluxes belonging to Population B are much higher (mean: 5543 g m- 2 day- 1). This low degassing rate probably reflects the low permeability of the system, a consequence of the intense hydrothermal alteration observed in the upper 800 m of volcanic rocks. An attempt to interpret the origin and transport mechanism of these fluxes is proposed by means of flux ratios as well as by numerical modeling. Measurements with CO2/CH4 and CO2/H2S flux ratios similar to mass ratios

  2. Comunidades liquénicas como bioindicadores de calidad del aire del Valle de Aburrá

    Directory of Open Access Journals (Sweden)

    Jaramillo Ciro1 Margarita María

    2011-11-01

    Full Text Available Los líquenes han sido propuestos como bioindicadores de la calidad del aire por su alta sensibilidad a los cambios que afectan su abundancia, biomasa y vitalidad. Para evaluar las afectaciones que los líquenes manifiestan como consecuencia de la contaminación atmosférica, se seleccionaron dos áreas de muestreo en los alrededores de dos estaciones de la red de monitoreo de calidad del aire RedAire: el edificio Miguel de Aguinaga con alta contaminación y la Universidad de Medellín con baja contaminación. El monitoreo se realizó sobre las cortezas de 4 especies arbóreas como forofitos: Terminalia catappa Linneaus, Eritrina fusca Loureiro, Mangifera indica Linneaus y Fraxinus chinensis Roxb. Para los análisis se consideraron las variables cobertura liquénica por especie, vitalidad y fructificación del talo. Finalmente los datos de cobertura fueron utilizados para determinar el índice de pureza atmosférica (IPA y el factor Q. Los resultados evidenciaron que de las 8 especies de líquenes encontradas, Canoparmelia sp. y Parmotrema austrosinensis (Zahlbr Hale. son las más sensibles y apropiadas para estudios de calidad del aire en el Valle de Aburrá. Los análisis estadísticos realizados a los valores de abundancia relativa por forofito mostraron que Fraxinus chinensis Roxb es la especie vegetal portante más apropiada para estudios de líquenes bioindicadores en el Valle de Aburrá.

  3. CULTO A LA VIRGEN DEL VALLE COMO CREENCIA AUTÓCTONA EN LAS ISLAS ORIENTALES VENEZOLANAS

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    Natalia Bondarenko

    2016-01-01

    Full Text Available Se analiza el origen del culto a la Virgen del Valle en el estado insular Nueva Esparta (Venezuela y su relación con las creencias autóctonas de los indígenas guaiqueríes, por un lado, y la creencia católica clásica en la Virgen María, por el otro. Luego de describir la religiosidad de los guaiqueríes en la época prehispánica y presentar las características de la creencia en la Virgen María en la España medieval, se argumenta que el culto a la Virgen se inició en Venezuela en el período colonial, cuando algunos guaiqueríes la aceptaron debido a su semejanza con los cemíes y el carácter matriarcal de su sociedad, para luego, en el período republicano, adherirse masiva y definitivamente a la Virgen, incorporándola a su panteón de divinidades a partir de un suceso histórico insólito. Ellos rendían culto a la Virgen a su modo ancestral, por lo cual esta creencia no puede ser considerada como sincrética. Se concluye que en las islas neoespartanas, aunque con el nombre de una Virgen católica, el culto a la Virgen del Valle representa una creencia autóctona guaiquerí que persiste a través del tiempo, desplegando aspectos católicos solo en los rituales formales de la iglesia.

  4. Rendimiento térmico de calderas bagaceras modernas en Tucumán, R. Argentina Thermal efficiency of modern bagasse boilers in Tucumán, Argentina

    Directory of Open Access Journals (Sweden)

    Federico J. Franck Colombres

    2011-12-01

    Full Text Available Se evaluaron tres calderas de vapor modernas instaladas en ingenios azucareros de Tucumán, R. Argentina, equipos que se encuadran dentro de las tecnologías de producción más limpia. Tomando como base la metodología de cálculo de la eficiencia térmica de generadores de vapor desarrollada en 2008 por la Sección Ingeniería y Proyectos Agroindustriales de la Estación Experimental Agroindustrial Obispo Colombres, y a partir de los datos recolectados por medio de mediciones y balances de materia y energía, se determinaron sus principales variables características de operación. Las eficiencias energéticas determinadas para cada una fueron del 73,5%; 75,2% y 77,3%. Se realizó además una comparación con las calderas de vapor convencionales y se determinó el ahorro de bagazo que puede obtenerse con las calderas modernas, el cual resultó ser de un 27,6%. Como una ventaja adicional, se hace mención a la posibilidad de mejora del rendimiento térmico del ciclo motriz de la planta, que viene acompañada con el aumento de la presión de trabajo de la caldera.Three modern steam boilers, installed in sugar mills in Tucumán, R. Argentina, to attain a cleaner production, were evaluated. Their major operating variables were determined using the methodology for calculating thermal efficiency of steam generators developed by Sección Ingeniería y Proyectos Agroindustriales of Estación Experimental Agroindustrial Obispo Colombres in 2008, and data obtained from measurements and material and energy balances. Energy efficiency values determined for each boiler were 73.5%, 75.2% and 77.3%, respectively. A comparison with conventional steam boilers was drawn and it was found that bagasse savings amounted to about 27.6% when modern boilers were used. The possibility of improving the thermal efficiency of the plant cycle by increasing boiler pressure is mentioned as an additional advantage.

  5. Red Piloto de Información Hidrometeorológica para el Valle de Aburrá.

    OpenAIRE

    Jiménez Mejía, José Fernando; Ramírez, Carlos Julio; Ochoa Jaramillo, Andrés; Poveda Jaramillo, Germán; Zapata Jaramillo, Carlos Mario; Marín Morales, María Isabel

    2008-01-01

    El Aula Taller de Ciencia y Tecnología de la Escuela del Maestro (Municipio de Medellín) y el Aula Taller Leonardo Da Vinci (Universidad Nacional de Colombia, Sede Medellín) vienen trabajando desde hace varios años en una propuesta pedagógica novedosa para el estudio de las ciencias naturales. Esta iniciativa dio origen a una red preliminar de estaciones meteorológicas didácticas en más de diez colegios y escuelas en municipios del Valle de Aburrá, las cuales están en funcionamiento. Este pro...

  6. DINÁMICA NUTRICIONAL EN CINCO PARRONES DE DIFERENTE PRODUCTIVIDAD DEL VALLE CENTRAL REGADO DE CHILE

    OpenAIRE

    Ruiz S., Rafael

    2000-01-01

    Se efectuó un estudio comparativo de aspectos nutricionales del suelo y de la planta en 5 parronales de uva de mesa cv. Thompson Seedless con un historial muy diferente de productividad y vigor, en el valle central de Chile, durante 4 años. Durante este período se efectuaron análisis nutricionales mensuales, que incluyeron además de N, P y K total, fracciones de N de reserva como arginina y aminoácidos totales y carbohidratos de reserva en la parte aérea (sarmientos y brotes) y en raíces. El ...

  7. La gestión tecnológica: una herramienta para el desarrollo de la Cadena Productiva del Ají en el Valle del Cauca

    Directory of Open Access Journals (Sweden)

    Omar Rada Barona

    2011-01-01

    diferentes actores: Secretaría de Agricultura de la Gobernación del Valle del Cauca, Fundación Carvajal, y a la Asociación de Productores y Comercializadores Agrícolas - Agrovac. Como resultado, se observa que la cadena productiva del ají, en el Valle del Cauca, adolece de la aplicación de herramientas tecnológicas que permitan identificar nuevos mercados y analizar la capacidad de la competencia de los productores. El desarrollo de la fase 1: Identificación de la Cadena Productiva del Ají, permite concluir que es necesario implementar la gestión tecnológica en cada uno de los procesos de la cadena, a partir del empoderamiento de los agricultores que participan en la Asociación de Productores y Comercializadores Agrícolas, Agrovac, para que éstos realmente aprovechen las oportunidades de crecimiento y desarrollo.

  8. Ordenamiento territorial, turismo y ambiente en Valle de Bravo, México

    Directory of Open Access Journals (Sweden)

    Nancy Sierra López

    2011-01-01

    Full Text Available Detrás de ese paisaje idílico de agua, bosques y arquitectura, que la mercadotecnia ofrece y que la tradición evoca, se desarrollaron fuertes conflictos de intereses, necesidades sociales insatisfechas, así como la depredación ambiental constante. En Valle de Bravo pueden observarse paisajes con diferentes visiones y lógicas socioeconómicas, como resultado de un conjunto de políticas de carácter territorial formuladas por el Estado y por la iniciativa privada, con el objetivo de fomentar la actividad turística como eje del desarrollo capitalista. El paisaje creado en algunas zonas ofrece una imagen de prosperidad y confort, mientras que en otras es posible observar la segregación socioterritorial que esta actividad ha generado y que excluye a la mayoría de sus habitantes de los beneficios que el turismo puede traer.

  9. Factores de riesgo que determinan la transmisión de la leishmaniasis en el valle Llaucano, Chota-Cajamarca

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    Víctor Zorrilla

    2005-03-01

    Full Text Available Objetivos: Determinar los factores de riesgo asociados con la transmisión de leishmaniasis. Material y Métodos: Se entrevistó 727 personas en 140 viviendas de 8 localidades del valle Llaucano, Chota, Cajamarca. Los factores de riesgo fueron analizados mediante el cálculo del odds ratio, con límites de confianza al 95%, utilizando el pro­grama EpiInfo 2000. Resultados: Se diagnosticó 206 casos de leishmaniasis, 63 lesiones activas y 143 cicatrices. La leishmaniasis se presenta en todos los grupos de edad y ambos sexos están afectados en proporciones similares, siendo más frecuente en menores de 10 años. El alto porcentaje de lesiones en cara y miembros superiores, sugiere una transmisión domiciliaria de la enfermedad. Los factores de riesgo asociados con la transmisión de la leishmaniasis en el valle de Llaucano, son los siguientes: viviendas dispersas ubicadas en áreas rurales (OR 3,97, IC95% 1,94-8,14, dormir en viviendas improvisadas en medio de las chacras en condiciones precarias (OR 4,59, IC95% 3,22-6,54, cultivos de café (OR 7,83, IC95% 3,57-17,17, caña de azúcar (OR 4,99, IC95% 2,42-10,27 y frutas (OR 3,62, IC95% 1,72-7,61 en peridomicilio; hacinamiento con 6 ó más personas por vivienda (OR=3,25, IC95% 1,50-7,10; animales domésticos en el domicilio, principalmente perros (OR=4,03, IC95% 1,98-8,20; flebotominos en el ambiente domiciliario (OR=5,62, IC95% 2,68-11,82, que ingresan a través de las paredes de "tapial". Paccha Baja, Chontabamba y Matibamba son los focos de más alta transmisión de leishmaniasis. La prevalencia acumulada fue de 283,4/1000 hab. Conclusiones: El valle de Llaucano es zona endémica con elevada velocidad de propagación de la leishmaniasis; la transmisión de la enfermedad está asociada a factores de vivienda y comportamiento humano.

  10. Compte rendu de : La vallée électrique,Foëx E. (photographies) et Broennimann T. (textes), 2006, Paris, InFolio éditions, 164 p., 210 photographies en noir et blanc

    OpenAIRE

    Buisson, André

    2008-01-01

    Réunies sous le titre La vallée électrique, 210 photographies en noir et blanc du photographe Emmanuel Foëx illustrent l’architecture industrielle, l’urbanisme et le paysage dans l’Arc alpin. Comme un ouvrage classique, l’album est divisé en trois parties : La centrale, le réseau, le transformateur. L’auteur est parti de l’évidence qu’à travers l’arc alpin, les sillons des vallées sont constellés d’usines consacrées à la fabrication de l’électricité (La centrale). La montagne, telle un châtea...

  11. Estudio preliminar de la fauna Amphibia del valle de Sibundoy, Alto Putumayo, Colombia

    Directory of Open Access Journals (Sweden)

    Jonh Jairo Mueses-Cisneros

    2004-07-01

    (Valle de Sibundoy y por localidades muestreadas, se hace una comparación con las faunas realizadas en el transecto Napo en Ecuador y en el transecto Montañita-Alto Gabinete en Caquetá y se presenta una clave taxonómica y una serie de fotografías para facilitar su  reconocimiento. El estudio además aporta cinco especies nuevas para la ciencia, amplía el rango altitudinal de otras ocho y presenta tres más para ser incluidas al listado general de las especies de anfibios de Colombia, las cuales habían sido ya anteriormente reportadas para el país por otros autores, pero no habían sido tenidas en cuenta en el último listado.

  12. Nesting ecology of the olive ridley sea turtle (Lepidochelys olivacea) (Cheloniidae) at el Valle Beach, northern pacific, Colombia; Ecologia de anidacion de la tortuga golfina (Lepidochelys olivacea) (Cheloniidae) en la Playa El Valle, pacifico norte, Colombia

    Energy Technology Data Exchange (ETDEWEB)

    Barrientos Munoz, Karla G; Gallego, Cristian Ramirez; Paez, Vivian

    2014-07-01

    The olive ridley (Lepidochelys olivacea) is the most common sea turtle to nest in Colombia. El valle beach is considered the most important nesting beach for this species in South America. Intensive direct capture of nesting females and egg poaching for consumption and local commercial purposes has been a common practice for years. We conducted an analysis of the nesting ecology of the olive ridley on el valle beach in the northern pacific of Colombia in 2008. A total of 164 clutches were transferred to an artificial hatchery for protection. The peak of nesting occurred from the second half of August until the end of September, accounting for 64.6 % of all nests. Along the beach, the section most frequently used was section 3, with 26 % of the nests. The nests were laid mainly in zone 3.69 %. We encountered 55 nesting females and marked 46 of them. Mean CCL was 64.9 ± 2.4 cm and mean CCW was 68.6 ± 2.6 cm. females laid on average of 87.3 ± 14.2 eggs per clutch. We recorded two nesting events per female, with a mean inter-nesting period of 18.8 ± 4.2 days. The reproductive output for the season was 181.5 ± 34.8 eggs / female. Mean hatching success was 81.1 ± 12.1 % and mean emergence success was 77.6 ± 12.7 %. The incubation period was 65 ± 4.7 days. Our study is a valuable contribution to knowledge of the reproductive ecology of the olive ridley population regionally and globally.

  13. Acceso a la tierra de los ex huasipungueros en la hacienda "Carpuela", en el valle del Chota.

    OpenAIRE

    Villa Zura, Marco Patricio

    2015-01-01

    El propo?sito del presente estudio de investigacio?n es abordar como fue el acceso a la tierra de los ex huasipungueros en la hacienda Carpuela en el Valle del Chota, parroquia Ambuqui?, canto?n Ibarra, Provincia de Imbabura, quienes fortalecieron la organizacio?n comunitaria, apoya?ndose en la Ley de Reforma Agraria, ejecutada por el Instituto Ecuatoriano de Reforma Agraria y Colonizacio?n de 1964 y la de 1973 que continuo. Adema?s autores teo?ricos reflejan la historia de los jesuitas qu...

  14. Writing on the Edge: Impressions of a U.S.-Mexico Border in Rolando Hinojosa's Estampas del Valle

    OpenAIRE

    CANTU, MARIA GUADALUPE

    2011-01-01

    This dissertation engages in a critical reading of Rolando Hinojosa's early fiction in Estampas del Valle as an example of a unique border literature that highlights the multiplicity of elements that exist along the Rio Grande. By using the work of an author that has direct experience with life along the U.S.-Mexico border the aim of this study is to look at how the border region and its cultural and spatial manifestations impact on writings concerned with memory, the personal and the self. ...

  15. El Paleolítico Medio en el Cáucaso Meridional: la Cueva Doble (Valle de Tsutskhvati, República de Georgia

    Directory of Open Access Journals (Sweden)

    Fernando DÍEZ MARTÍN

    2010-08-01

    Full Text Available El presente trabajo recoge los principales resultados derivados de la intervención arqueológica acometida entre los años 2002 y 2003 en el Valle de Tsutskhvati (República de Georgia, principalmente centrados en una nueva ronda de excavaciones en la Cueva Doble. Los estudios estratigráficos, tecnológicos, tafonómicos y polínicos permiten arrojar nuevos datos, complementarios a los obtenidos en la cercana cueva de Ortvale Klde, sobre las comunidades neandertales que habitaron la región del Cáucaso meridional, uno de los entornos geográficos en los que sobrevivieron los últimos representantes de esta especie. Mientras que los completos trabajos arqueológicos abordados en la cueva de Ortvale Klde han permitido contar con un amplio programa de datación para la presencia neandertal en dicha cavidad, el resto de los yacimientos del mismo periodo siguen presentando una cierta indefinición contextual. A pesar de ello, se acepta que la presencia neandertal en el valle de Tsutskhvati debió situarse en el mismo marco temporal que en Ortvale Klde. Aunque tanto la Cueva Doble, motivo de esta publicación, como la famosa Cueva del Bronce carecen hoy en día de contextos cronológicos fiables, es necesario señalar que estos yacimientos del valle de Tsutskhvati vienen siendo recurrentemente citados en el debate sobre el fin de los neandertales y la llegada de las primeras comunidades sapiens a la región caucásica. Es por ello por lo que la información novedosa aquí presentada (los últimos trabajos en Tsutskhvati se llevaron a cabo en la década de 1970 posee un indudable interés, a pesar de las limitaciones cronológicas, para ampliar nuestro conocimiento sobre este importante capítulo de la Prehistoria europea.

  16. Zircon and whole-rock Zr/Hf ratios as markers of the evolution of granitic magmas: Examples from the Teplice caldera (Czech Republic/Germany)

    Czech Academy of Sciences Publication Activity Database

    Breiter, Karel; Škoda, R.

    2017-01-01

    Roč. 111, č. 4 (2017), s. 435-457 ISSN 0930-0708 R&D Projects: GA ČR GA14-13600S Institutional support: RVO:67985831 Keywords : Zr/Hf value * zircon * Teplice caldera * rhyolite * rare-metal granite * Cínovec deposit Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Mineralogy Impact factor: 1.236, year: 2016

  17. Mechanical conditions and modes of paraglacial deep-seated gravitational spreading in Valles Marineris, Mars

    Science.gov (United States)

    Makowska, Magdalena; Mège, Daniel; Gueydan, Frédéric; Chéry, Jean

    2016-09-01

    Deep-seated gravitational spreading (DSGS) affects the slopes of formerly glaciated mountain ridges. On Mars, DSGS has played a key role in shaping the landforms of the giant Valles Marineris troughs. Though less spectacular, DSGS is common in terrestrial orogens, where understanding its mechanics is critical in the light of the ongoing climate change because it is a potential source of catastrophic landslides in deglaciated valleys. We conducted parametric numerical studies in order to identify important factors responsible for DSGS initiation. DSGS models are computed using an elastoviscoplastic finite element code. Using ADELI's software, we reproduce topographic ridge spreading under the effect of valley unloading. Two types of spreading topographic ridges are investigated, homogeneous or with horizontal rheological layering. We find that gravitational instabilities are enhanced by high slopes, which increase gravitational stress, and low friction and cohesion, which decrease yield stress. In the unlayered ridge, instability is triggered by glacial unloading with plastic strain concentration inside the ridge and at the base of the high slopes. Vertical fractures develop in the upper part of the slope, potentially leading to fault scarps. Ridge homogeneity promotes a deformation mode controlled by uphill-facing normal faulting and basal bulging. In the second case, the ridge encompasses horizontal geological discontinuities that induce rock mass anisotropy. Discontinuity located at the base of the slope accumulates plastic strain, leading to the formation of a sliding plane evolving into a landslide. The presence of a weak layer at ridge base therefore promotes another slope deformation mode ending up with catastrophic failure. Mechanical conditions and slope height being equal, these conclusions can probably be extrapolated to Earth. Compared with Mars, DSGS on Earth is inhibited because terrestrial topographic gradients are lower than in Valles Marineris, an

  18. Inferences on the hydrothermal system beneath the resurgent dome in Long Valley Caldera, east-central California, USA, from recent pumping tests and geochemical sampling

    Science.gov (United States)

    Farrar, Christopher D.; Sorey, Michael L.; Roeloffs, Evelyn; Galloway, Devin L.; Howle, James F.; Jacobson, Ronald

    2003-10-01

    Quaternary volcanic unrest has provided heat for episodic hydrothermal circulation in the Long Valley caldera, including the present-day hydrothermal system, which has been active over the past 40 kyr. The most recent period of crustal unrest in this region of east-central California began around 1980 and has included periods of intense seismicity and ground deformation. Uplift totaling more than 0.7 m has been centered on the caldera's resurgent dome, and is best modeled by a near-vertical ellipsoidal source centered at depths of 6-7 km. Modeling of both deformation and microgravity data now suggests that (1) there are two inflation sources beneath the caldera, a shallower source 7-10 km beneath the resurgent dome and a deeper source ˜15 km beneath the caldera's south moat and (2) the shallower source may contain components of magmatic brine and gas. The Long Valley Exploration Well (LVEW), completed in 1998 on the resurgent dome, penetrates to a depth of 3 km directly above this shallower source, but bottoms in a zone of 100°C fluid with zero vertical thermal gradient. Although these results preclude extrapolations of temperatures at depths below 3 km, other information obtained from flow tests and fluid sampling at this well indicates the presence of magmatic volatiles and fault-related permeability within the metamorphic basement rocks underlying the volcanic fill. In this paper, we present recently acquired data from LVEW and compare them with information from other drill holes and thermal springs in Long Valley to delineate the likely flow paths and fluid system properties under the resurgent dome. Additional information from mineralogical assemblages in core obtained from fracture zones in LVEW documents a previous period of more vigorous and energetic fluid circulation beneath the resurgent dome. Although this system apparently died off as a result of mineral deposition and cooling (and/or deepening) of magmatic heat sources, flow testing and tidal

  19. Bienestar y participación, una construcción local. Versalles, Valle del Cauca

    Directory of Open Access Journals (Sweden)

    Mark Lundy

    1999-01-01

    Full Text Available El concepto de desarrollo local se ha venido construyendo tanto en el escenario académico como en los diferentes espacios de trabajo comunitario existentes en Colombia. El presente artículo retoma una de estas experiencias, la del Comité de Participación Comunitaria del municipio de Versalles, Valle del Cauca, y la desglosa por medio de una descripción, el análisis de los logros y algunas reflexiones acerca de lo vivido. El ejercicio permite avanzar en la definición de algunos conceptos, clarificar retos futuros, proponer algunos pasos necesarios para potenciar el desarrollo humano e identificar ciertas variables claves en el proceso de desarrollo local.

  20. Valles Marineris as a Cryokarstic Structure Formed by a Giant Dyke System: Support From New Analogue Experiments

    Science.gov (United States)

    Ozeren, M. S.; Sengor, A. M. C.; Acar, D.; Ülgen, S. C.; Onsel, I. E.

    2014-12-01

    Valles Marineris is the most significant near-linear depression on Mars. It is some 4000 km long, up to about 200 km wide and some 7 km deep. Although its margins look parallel at first sight, the entire structure has a long spindle shape with significant enlargement in its middle (Melas Chasma) caused by cuspate slope retreat mechanisms. Farther to its north is Hebes Chasma which is an entirely closed depression with a more pronounced spindle shape. Tithonium Chasma is a parallel, but much narrower depression to its northeast. All these chasmae have axes parallel with one another and such structures occur nowhere else on Mars. A scabland surface exists to the east of the Valles Marineris and the causative water mass seems to have issued from it. The great resemblance of these chasmae on mars to poljes in the karstic regions on earth have led us to assume that they owed their existence to dissolution of rock layers underlying them. We assumed that the dissolving layer consisted of water ice forming substantial layers, in fact entirely frozen seas of several km depth. We have simulated this geometry by using bentonite and flour layers (in different experiments) overlying layers of ice in which a resistant coil was used to simulate a dyke. We used different thicknesses of bentonite and flour overlying ice layers again of various thicknesses. The flour seems to simulate the Martian crust better because on Mars, g is only about 3/8ths of its value on Earth, so (for equal crustal density) the depth to which the cohesion term C remains important in the Mohr-Coulomb shear failure criterion is about 8/3 times greater. As examples we show two of those experiments in which both the rock analogue and ice layers were of 1.5 cm. thick. Perfect analogues of the Valles Marineris formed above the dyke analogue thermal source complete with the near-linear structure, overall flat spindle shape, cuspate margins, a central ridge, parallel side faults, parallel depressions resembling

  1. The relation of catastrophic flooding of Mangala Valles, Mars, to faulting of Memnonia Fossae and Tharsis volcanism

    International Nuclear Information System (INIS)

    Tanaka, K.L.; Chapman, M.G.

    1990-01-01

    Detailed stratigraphic relations indicate two coeval periods of catastrophic flooding and Tharsis-centered faulting (producing Memnonia Fossae) in the Mangala Valles region of Mars. Major sequences of lava flows of the Tharsis Montes Formation and local, lobate plains flows were erupted during and between these channeling and faulting episodes. First, Late Hesperian channel development overlapped in time the Tharsis-centered faulting that trends north 75 degree to 90 degree E. Next, Late Hesperian/Early Amazonian flooding was coeval with faulting that trends north 55 degree to 70 degree E. In some reaches, resistant lava flows filled the early channels, resulting in inverted channel topography after the later flooding swept through. Both floods likely originated from the same graben, which probably was activated during each episode of faulting. Faulting broke through groundwater barriers and tapped confined aquifers in higher regions west and east of the point of discharge. The minimum volume of water required to erode Mangala Valles (about 5 x 10 12 m 3 ) may have been released through two floods that drained a few percent pore volume from a relatively permeable aquifer. The peak discharges of the floods may have lasted from days to weeks. The perched water discharged from the aquifer may have been produced by hydrothermal groundwater circulation induced by Tharsis magmatism, tectonic uplift centered at Tharsis Montes, and compacting of saturated crater ejecta due to loading by lava flows

  2. Movilidad y dieta en el valle de El Mauro (31° 57’ S. - 71° 01’ W.), Norte Semiárido de Chile, entre 8350-929 CAL. AP

    OpenAIRE

    Gómez, Pablo; Pacheco, Aryel

    2016-01-01

    El valle de El Mauro se localiza a 40 km del Océano Pacífico (1000 msnm) en el extremo meridional del Norte Semiárido de Chile. Para contribuir al conocimiento de la movilidad y dieta prehispánica en el valle se analizó el radiocarbono y los isótopos de estroncio (87Sr/86Sr), oxígeno (δ¹13O), nitrógeno (δ¹13N) y carbono (δ13C) de 21 individuos y un entierro múltiple (NMI=3).Los datos indican el arribo esporádico de individuos de origen y/o hábitat costeros entre 8350-3000 cal. AP. Posterior a...

  3. 238U-230Th dating of chevkinite in high-silica rhyolites from La Primavera and Yellowstone calderas

    Science.gov (United States)

    Vazquez, Jorge A.; Velasco, Noel O.; Schmitt, Axel K.; Bleick, Heather A.; Stelten, Mark E.

    2014-01-01

    Application of 238U-230Th disequilibrium dating of accessory minerals with contrasting stabilities and compositions can provide a unique perspective on magmatic evolution by placing the thermochemical evolution of magma within the framework of absolute time. Chevkinite, a Th-rich accessory mineral that occurs in peralkaline and metaluminous rhyolites, may be particularly useful as a chronometer of crystallization and differentiation because its composition may reflect the chemical changes of its host melt. Ion microprobe 128U-230Th dating of single chevkinite microphenocrysts from pre- and post-caldera La Primavera, Mexico, rhyolites yields model crystallization ages that are within 10's of k.y. of their corresponding K-Ar ages of ca. 125 ka to 85 ka, while chevkinite microphenocrysts from a post-caldera Yellowstone, USA, rhyolite yield a range of ages from ca. 110 ka to 250 ka, which is indistinguishable from the age distribution of coexisting zircon. Internal chevkinite-zircon isochrons from La Primavera yield Pleistocene ages with ~5% precision due to the nearly two order difference in Th/U between both minerals. Coupling chevkinite 238U-230Th ages and compositional analyses reveals a secular trend of Th/U and rare earth elements recorded in Yellowstone rhyolite, likely reflecting progressive compositional evolution of host magma. The relatively short timescale between chevkinite-zircon crystallization and eruption suggests that crystal-poor rhyolites at La Primavera were erupted shortly after differentiation and/or reheating. These results indicate that 238U-230Th dating of chevkinite via ion microprobe analysis may be used to date crystallization and chemical evolution of silicic magmas.

  4. El poblamiento humano antiguo en el valle alto del Lozoya (Madrid

    Directory of Open Access Journals (Sweden)

    Belén Márquez

    2008-01-01

    Full Text Available La localización en superficie en el término municipal de Lozoya (Madrid de un conjunto de piezas de industria lítica achelense permite retrotraer el primer poblamiento de esta zona al Pleistoceno medio, cuando hasta la fecha las evidencias más antiguas en el valle alto del río Lozoya se remontaban a inicios del Pleistoceno superior. El nuevo hallazgo sitúa al río Lozoya en relación cultural con el poblamiento humano antiguo de los ríos Jarama y Manzanares.The discovery of a surface sample of Acheulean lithic industry at the Lozoya district (Madrid takes back to the Middle Pleistocene the first human peopling of this area. Until now themost ancient evidences at the Upper Lozoya Valley went back to the initial Upper Pleistocene. The new findings place the Lozoya River in cultural relation with the ancient human population of Jarama and Manzanares Rivers.

  5. Incidencia del fenómeno ENSO en la hidroclimatología del valle del río Cauca-Colombia

    Directory of Open Access Journals (Sweden)

    1998-01-01

    Full Text Available IMPACT DU PHÉNOMÈNE ENSO SUR L’HYDROCLIMATOLOGIE DU RIO CAUCA-COLOMBIE. On présente dans cet article quelques unes des manifestations du phénomène et leur impact sur la pénurie des ressources en eau dans la vallée du rio Cauca, au cours des périodes sèches ainsi que les crues et inondations, provoquées par les périodes excédentaires. L’évaluation de valeurs extrêmes des débits des rivières montre des différences liées à l’occurrence d’un El Niño. En présence d’un El Niño, les débits maximums seront plus forts et les débits d’étiages plus faibles. Au cours de ces périodes, on observe donc une augmentation du risque d’inondation au cours de la saison des pluies, alors que la quantité d’eau diminue au cours des périodes sèches avec un risque accru d’incendie de forêt. En este trabajo, se presentan algunas de las manifestaciones del Fenómeno y el impacto que ocasiona en la disponibilidad hídrica del Valle del Cauca durante la fase Cálida (Niño, por efecto del déficit hídrico, y durante la fase fría (AntiNiño o Niña por exceso de lluvias. La evaluación de los caudales mínimos de los ríos del Valle del Río Cauca, se asocia con los años de ocurrencia de la fase cálida, mientras los caudales medios máximos se asocian a períodos de ocurrencia de la fase fría (AntiNiño o Niña. Durante el Niño se presentan sequías, incendios forestales, pérdidas de cultivos, de perecederos, disminución de la pesca, incremento de enfermedades y racionamiento de energía, mientras que durante la Niña se presentan mayores riesgos de inundación, desbordamientos, desastres, erosión y destrucción de la infraestructura vial e hidráulica. INCIDENCE OF ENSO PHENOMENON IN THE HYDROCLIMATOLOGY OF THE RÍO CAUCA VALLEY-COLOMBIA. In this paper, the impacts of the El Niño and La Niña o AntiNiño phenomena on the water resources of the Valle del Cauca (Colombia are considered low flows in the rivers are associated with

  6. Constraints on tree seedling establishment in montane grasslands of the Valles Caldera, New Mexico

    Science.gov (United States)

    Jonathan D. Coop; Thomas J. Givnish

    2008-01-01

    Montane and subalpine grasslands are prominent, but poorly understood, features of the Rocky Mountains. These communities frequently occur below reversed tree lines on valley floors, where nightly cold air accumulation is spatially coupled with fine soil texture. We used field experiments to assess the roles of minimum temperature, soil texture, grass competition, and...

  7. Trabajo Multidisciplinar Universidad-Empresa en Agroindustria Cafetera del Valle del Cauca, Colombia Multidisciplinary Collaboration University-Industry in a Coffee Growing Enterprise of Valle del Cauca, Colombia

    Directory of Open Access Journals (Sweden)

    Jaime A. Aguilar Zambrano

    2009-12-01

    Full Text Available Este artículo presenta una metodología y los resultados obtenidos de un proyecto de actuación multidisciplinar en una relación universidad-empresa para favorecer la innovación. Desde la universidad participaron profesores y estudiantes de los Programas de Ingeniería Electrónica e Ingeniería Industrial, y la empresa fue una cooperativa de cultivadores de café orgánico llamada Asociación ACOC, ubicada en el centro del Valle del Cauca en Colombia. Se plantearon dos hipótesis para el proyecto, la primera: el trabajo multidisciplinar genera mejores resultados en la solución de problemas de las pequeñas empresas porque contempla el problema en una forma sistémica; la segunda: el trabajo independiente de cada disciplina una vez identificada la problemática técnica provee resultados satisfactorios para el conjunto del problema. La primera hipótesis fue verificada y la segunda se verificó parcialmente. Se concluye que las relaciones universidad-empresa con un aporte tecnológico multidisciplinar mejoran significativamente el trabajo de la pequeña empresa. La empresa debe involucrarse de manera activa para que los resultados perduren en el tiempo y la visión sistémica de los problemas fortalece el trabajo de las pequeñas empresas.This article shows a methodology and the results obtained from a multidisciplinary project between the University and Enterprise which encourages innovation. The University participated with its faculty members and students enrolled in the programs of industrial engineering and electronic engineering, and the Enterprise was a group of organic coffee farmers (called by its founders Asociación ACOC located in the center of Valle del Cauca, Colombia. Two hypotheses were formulated for the project. The first, multidisciplinary work produces better results in solving problems of small businesses because it considers the problem in a systemic way. The second, independent work from each field of study, once the

  8. Las diócesis del Valle del Cauca (Colombia en el siglo XX: Hacia el fortalecimiento de la modernización

    Directory of Open Access Journals (Sweden)

    Antonio José Echeverry Pérez

    2014-07-01

    Full Text Available El presente artículo hace un recorrido histórico (consultando fundamentalmente los archivos diocesanos, en su mayoría inéditos, por la instauración de las principales diócesis creadas en el Departamento del Valle del Cauca (Colombia durante el siglo XX: Cali, Palmira, Buenaventura, Cartago y Buga. Se muestra como la Iglesia constituye un proyecto fundamental de modernización religiosa, que se denota ante todo en la extensión de su presencia en el territorio vallecaucano. Proceso que inicia con la desfragmentación del gran territorio de la arquidiócesis de Popayán, con lo cual cada diócesis creada logra impulsar sus propios procesos de generación de parroquias, centros educativos y de beneficencia, logrando con esto, construir la iglesia vallecaucana y fortalecer la religión católica tanto en los sectores rurales como en los espacios urbanos del departamento del Valle del Cauca. Cada nueva diócesis se inscribe además, en su propia coyuntura local de desarrollo y modernización económica y social.

  9. Studying disability and disability studies: shifting paradigms of LDA synthesis of responses to Reid and Valle.

    Science.gov (United States)

    Connor, David J

    2005-01-01

    In this article, I discuss the 11 diverse responses to Reid and Valle's work on the discursive practice of learning disabilities (LD), implications for instruction, and parent-school relations. I highlight key ideas from each article and then focus on three common areas of interest shared by most respondents: the unacceptable status quo of schooling practices; desired changes in schooling practices; and knowledge production in the field of special education and its relation to schooling practices. In light of the many issues raised, I urge the need for a reflective turn in the field of LD and for openness toward diversification of thought.

  10. Efecto de la calidad de agua del acuífero Valle de Guadalupe en la salinidad de suelos agrícolas Water quality effect on the Valle de Guadalupe aquifer in the agricultural soils salinity

    OpenAIRE

    Jorge Arturo Salgado Tránsito; Oscar Palacios Vélez; Arturo Galvis Spínola; Francisco Gavi Reyes; Enrique Mejía Sáenz

    2012-01-01

    Para determinar el efecto de la calidad del agua en el Acuífero del Valle de Guadalupe, Baja California, México, en la salinidad de los suelos agrícolas se midió el pH, conductividad eléctrica, sólidos disueltos totales y la concentración de los principales iones en las aguas de 66 pozos, de un total de 754 que se encontraban en operación en el acuífero durante 2009 .Y se analizó en el extracto de pasta de saturación de muestras de suelo el pH, conductividad eléctrica, carbonato, bicarbonato,...

  11. Power scaling of laser diode pumped Pr3+:LiYF4 cw lasers: efficient laser operation at 522.6 nm, 545.9 nm, 607.2 nm, and 639.5 nm.

    Science.gov (United States)

    Gün, Teoman; Metz, Philip; Huber, Günter

    2011-03-15

    We report efficient cw laser operation of laser diode pumped Pr(3+)-doped LiYF4 crystals in the visible spectral region. Using two InGaN laser diodes emitting at λ(P)=443.9 nm with maximum output power of 1 W each and a 2.9-mm-long crystal with a doping concentration of 0.5%, output powers of 938 mW, 418 mW, 384 mW, and 773 mW were achieved for the laser wavelengths 639.5 nm, 607.2 nm, 545.9 nm, and 522.6 nm, respectively. The maximum absorbed pump powers were approximately 1.5 W, resulting in slope efficiencies of 63.6%, 32.0%, 52.1%, and 61.5%, as well as electro-optical efficiencies of 9.4%, 4.2%, 3.8%, and 7.7%, respectively. Within these experiments, laser diode-pumped laser action at 545.9 nm was demonstrated for what is believed to be the first time.

  12. Campaniforme no funerario en la provincia de Toledo: el yacimiento de Las Vegas. De nuevo el Valle de Huecas

    Directory of Open Access Journals (Sweden)

    Barroso Bermejo, Rosa

    2015-06-01

    Full Text Available This article presents the latest results of the excavations at the site of Las Vegas in Huecas (Toledo. The site is located in an open area, near a stream and at the foot of the Valle de las Higueras necropolis. It is buried by a considerable colluvial deposition and was detected by geophysical survey. The site lacks structures and is made up of a single archaeological layer: it is a secondary deposit, containing Bell Beaker pottery and metal. A 14C sample has dated it to the second half of the 3rd millennium BC. Ceramics are the most abundant remain from this deposit. Macroscopic and X-ray Fluorescence (FRX analysis of the ceramics indicates a local production, the fast formation of this deposit, and its long-term exposure on the surface. We suggest that it was formed by cleaning and maintenance activities carried out in a nearby occupational area. We suggest that settlement occurred in the valley bottom, with occupations whose ceramic productions differ from the ones found in funerary contexts.Presentamos los resultados de los sondeos del yacimiento de Las Vegas, Huecas (Toledo. Se trata de un área abierta, junto al arroyo y al pie de la necrópolis de Valle de las Higueras. Un fuerte depósito de coluvión sepulta el yacimiento. Sin evidencias en superficie, su detección se realizó mediante prospección geofísica. Carece de estructuras y está formado por un único estrato, un depósito secundario que contiene campaniforme Ciempozuelos y metal, con una fecha C14 de la 2ª mitad del III milenio a.C. La cerámica es el material más abundante. Su estudio macroscópico y mediante fluorescencia de rayos X (FRX avala su producción local, la rápida formación del depósito y su larga exposición en superficie. Planteamos que el depósito procede de la limpieza y mantenimiento de un área de ocupación anexa. El patrón de poblamiento parece seguir las tierras bajas del valle con ocupaciones cuyas producciones cerámicas difieren de las de los

  13. Application of 2-D Inversion, to Magnetotelluric data on the Newberry Caldera, Oregon, for Potential Geothermal Power

    Science.gov (United States)

    Martin, T. P.; Schultz, A.

    2012-12-01

    Newberry Volcano lies immediately to the east of the Cascades volcanic arc in Oregon. However, Newberry differs from the main Cascadia arc, both chemically and in its physical setting. Newberry was formed by a combination of a shallow mantle source hot spot and subduction melts. This conclusion is suggested by depleted 3He/4He ratios and enriched Ba, Sr and Pb, which together indicate an oceanic crust subduction melt. As a result Newberry cannot be only formed from a stationary deep mantle source, or any other fixed source. Newberry also lies at the westernmost extent of an E-W oriented volcanic belt that appears to terminate in the east with the hot spot trace of the Snake River Plain/Yellowstone. Newberry's complex structure is also attributed to its proximity to the northernmost end of the Brothers Fault Zone (BFZ), related to regional tectonic fabric attributable to the transition to the Basin and Range province. The most recent volcanism at the caldera is a large obsidian flow, which erupted approximately 1,300 years ago. The United States Geological Survey considers Newberry to be a very high threat and to be "Central Oregon's Sleeping Giant." The western outer flank of the caldera is the site of an Enhanced Geothermal System (EGS) demonstration project being carried out by AltaRock Energy, Inc. and Davenport Newberry Holdings, LLC. EGS injection well stimulation is planned to open up a fracture network in a hot but dry series of altered basaltic/andesitic formations 2000-3000 m below ground level. Under Department of Energy funding, a collaboration between Oregon State University, the Department of Energy's National Energy Technology Laboratory, and Zonge International, Inc., seeks to image changes in fluid infiltration and migration, changes in porosity and permeability, and ultimately changes in the geothermal reservoir's capacity to produce thermal energy for sustained periods in response to changes in reservoir pressurization and injection rates. To

  14. Mecanismo de falla de los tubos del sobrecalentador de una caldera acuotubular

    Directory of Open Access Journals (Sweden)

    John Jairo Coronado Marín

    2007-09-01

    Full Text Available En este artículo se investigaron las causas de las fallas presentadas por fisuración longitudinal a partir de la superficie externa en los tubos del sobrecalentador de una caldera acuotubular. La superficie externa de los tubos presentó una capa de color blanco-rojizo que presentó cadenas parafínicas: C-H, grupos funcionales: C-O, N-H y compuestos de azufre, esta capa frágil impide la transferencia de calor, causando un aumento de temperatura del tubo. La falla se presentó por termofluencia debido al sobrecalentamiento de larga duración, la microestructura del tubo de acero en el lado externo presentó: crecimiento de grano, globulización de la cemen-tita y fisuras intergranulares que producen pérdidas de las propiedades mecánicas del acero. Las observaciones anteriores evidencian un deterioro de la microestructura facilitado por un material que no está en capacidad de operar usando exclusivamente bagazo como combustible.

  15. Contrasting styles of post-caldera volcanism along the Main Ethiopian Rift: Implications for contemporary volcanic hazards

    Science.gov (United States)

    Fontijn, Karen; McNamara, Keri; Zafu Tadesse, Amdemichael; Pyle, David M.; Dessalegn, Firawalin; Hutchison, William; Mather, Tamsin A.; Yirgu, Gezahegn

    2018-05-01

    The Main Ethiopian Rift (MER, 7-9°N) is the type example of a magma-assisted continental rift. The rift axis is populated with regularly spaced silicic caldera complexes and central stratovolcanoes, interspersed with large fields of small mafic scoria cones. The recent (latest Pleistocene to Holocene) history of volcanism in the MER is poorly known, and no eruptions have occurred in the living memory of the local population. Assessment of contemporary volcanic hazards and associated risk is primarily based on the study of the most recent eruptive products, typically those emplaced within the last 10-20 ky. We integrate new and published field observations and geochemical data on tephra deposits from the main Late Quaternary volcanic centres in the central MER to assess contemporary volcanic hazards. Most central volcanoes in the MER host large mid-Pleistocene calderas, with typical diameters of 5-15 km, and associated ignimbrites of trachyte and peralkaline rhyolite composition. In contrast, post-caldera activity at most centres comprises eruptions of peralkaline rhyolitic magmas as obsidian flows, domes and pumice cones. The frequency and magnitude of events varies between individual volcanoes. Some volcanoes have predominantly erupted obsidian lava flows in their most recent post-caldera stage (Fentale), whereas other have had up to 3 moderate-scale (VEI 3-4) explosive eruptions per millennium (Aluto). At some volcanoes we find evidence for multiple large explosive eruptions (Corbetti, Bora-Baricha, Boset-Bericha) which have deposited several centimetres to metres of pumice and ash in currently densely populated regions. This new overview has important implications when assessing the present-day volcanic hazard in this rapidly developing region. Supplementary Table 2 Main Ethiopian Rift outcrop localities with brief description of geology. All coordinates in Latitude - Longitude, WGS84 datum. Sample names (as listed in Supplementary Table 3a) follow outcrop name

  16. Aeromagnetic Study of the Nortern Acambay Graben and Amealco Caldera, Central Mexican Volcanic Belt

    Science.gov (United States)

    Gonzalez, T.

    2011-12-01

    The Mexican Volcanic Belt (MVB) is characterized by E-W striking faults which form a series of en echelon graben along its length. In the central region of the MVB is located the Acambay graben an intra-arc tectonic depression structure, of apparent Quaternary age, which gives rise to pronounced scarps over a distance of about 80 Km. and 15 to 35 Km wide. The general arrangement of the faults that constitute the Acambay graben shows E-W trend which defines the fronts of the graben exhibits a major fault discontinuity. The graben is limited of the north by the Acambay- Tixmadeje and Epitafio Huerta faults and in the south by the Pastores and Venta de Bravo faults.. In the northern wall in the graben is located the Amealco caldera. This volcanic center (approximately 10 km in diameter) was formed by several discrete volcanic events, which produced an ignimbrite which covers the area. It is partially cut by a regional fault and the southern portion of the Amealco Caldera was displaced by a normal faulting along a segment of the Epitafio Huerta system. Continued tectonic activity in the Acambay area is confirmed by recent seismic episodes The Amealco tuff is the most important volcanic unit because of its volume and distribution. Aeromagnetic data was obtained and analyzed the anomalies. The anomaly map was compared with the surface geology and larger anomalies were correlated with major volcanic features. Since our main interest was in mapping the subsurface intrusive and volcanic bodies, the total field magnetic anomalies were reduced to the pole by using the double integral Fourier method. The reduced to the pole anomaly map results in a simplified pattern of isolated positive and negative anomalies, which show an improved correlation with all major volcanic structures. For the analysis and interpretation of the anomalies, the reduced to the pole anomalies were continued upward at various reference levels. These operations result in smoothing of the anomaly field by

  17. Spatiotemporal Effects of Climate Variability and Urban Growth on the "Valle de Toluca" Aquifer (Mexico)

    Science.gov (United States)

    Mastachi-Loza, C. A.; Diaz-Delgado, C.; Esteller, M. V.; Gomez-Albores, M. A.; Becerril, R.; Ruiz-Gomez, M. D.

    2013-05-01

    Toluca city is located in the "Valle de Toluca" at the upper course of the Lerma river basin, is an important economic center which contributes with 1.2% of Gross National Product (GNP) since it is an industrial city, The city has grown due to the economic development sustained by the "Valle de Toluca" aquifer which provides water for human consumption, industrial facilities and crop irrigation. Recent studies have shown that in the last 50 years the annual precipitation rate in Toluca has increased 122 mm, whereas the daily minimum temperature has increased 1.1 °C and the daily maximum temperature has also increased 0.8 °C. These results show a general overview of the change in the climate conditions of the city; however they do not show the spatial distribution of the change. For this reason, the aim of this work was to evaluate the spatiotemporal change of precipitation rates and urban growth in order to determine their effects over the "Valle de Toluca" aquifer. In order to detect the urban growth, a supervised classification technique has been used taking into account Landsat TM satellite images between 1973, 1986, 2000 and 2005. A yearly spatiotemporal raster set of rainfall rates from 1980 to 2010 were obtained interpolating data from 812 climatologic stations. To evaluate the effect in annual precipitation rates and urban growth over the aquifer, we interpolate data from 38 piezometers from 1980 to 2010 to obtain a spatiotemporal raster set. The piezometric values correspond to the aquifer's upper level. The spatiotemporal raster sets were analyzed with the non-parametric Theil-Sen test to determine trends in piezometric levels and precipitation rates. Finally the urban growth, spatial-temporal trends of precipitation rates and piezometric levels were displayed in a GIS and then subjectively analyzed to figure out coincidences. An increase in annual precipitation rates (+87 mm) over Toluca's Valley during the last three decades was observed specially

  18. Le aree rurali dell’Appennino Ligure tra età romana e tardomedioevo. Ricerche storiche e archeologiche in alta Valle Scrivia / The rural areas of the Ligurian Appennines between Roman period and the Late Middle Ages. Historical and archaeological research in Valle Scrivia

    Directory of Open Access Journals (Sweden)

    Giovanni Battista Parodi

    2015-12-01

    Full Text Available La ricerca è incentrata sull’analisi delle forme e delle dinamiche del popolamento, delle strutture e dell’organizzazione del territorio dell’alta Valle Scrivia (area appenninica ubicata tra Genova e la pianura che mai è stata oggetto di ricerche sistematiche tra la tarda antichità e il XV secolo, alla luce delle fonti storiche, cartografiche e archeologiche. In particolare, la realizzazione di indagini di superficie e shovel tests ha consentito di ampliare e approfondire la conoscenza del comprensorio nel periodo in esame, fornendo interessanti spunti per lo studio delle aree rurali appenniniche. Gli elementi raccolti sono confl uiti all’interno di un database e di una piattaforma GIS appositamente creata. The research focuses on the analysis of settlement forms and dynamics, structures and organisation of upper Valle Scrivia (an area in the Apennines located between Genoa and the Po Valley that has never been the object of systematic studies between Late Antiquity and the 15th century in light of historical, cartographic and archaeological sources. In particular, carrying out surface surveys and shovel tests allowed to widen and increase the knowledge of the area in the period examined and provided interesting ideas for the study of rural areas in the Apennines. The elements that were gathered were inserted into a database and a GIS platform created on purpose.

  19. High power diode lasers emitting from 639 nm to 690 nm

    Science.gov (United States)

    Bao, L.; Grimshaw, M.; DeVito, M.; Kanskar, M.; Dong, W.; Guan, X.; Zhang, S.; Patterson, J.; Dickerson, P.; Kennedy, K.; Li, S.; Haden, J.; Martinsen, R.

    2014-03-01

    There is increasing market demand for high power reliable red lasers for display and cinema applications. Due to the fundamental material system limit at this wavelength range, red diode lasers have lower efficiency and are more temperature sensitive, compared to 790-980 nm diode lasers. In terms of reliability, red lasers are also more sensitive to catastrophic optical mirror damage (COMD) due to the higher photon energy. Thus developing higher power-reliable red lasers is very challenging. This paper will present nLIGHT's released red products from 639 nm to 690nm, with established high performance and long-term reliability. These single emitter diode lasers can work as stand-alone singleemitter units or efficiently integrate into our compact, passively-cooled Pearl™ fiber-coupled module architectures for higher output power and improved reliability. In order to further improve power and reliability, new chip optimizations have been focused on improving epitaxial design/growth, chip configuration/processing and optical facet passivation. Initial optimization has demonstrated promising results for 639 nm diode lasers to be reliably rated at 1.5 W and 690nm diode lasers to be reliably rated at 4.0 W. Accelerated life-test has started and further design optimization are underway.

  20. Syndrome of the caregiver in disability old patients and the psychosocial implications. Valle del Cauca, Colombia 2003-2004.

    OpenAIRE

    Eliana Dueñas; María Anggeline Martínez; Benjamín Morales; Claudia Muñoz; Ana Sofía Viáfara; Julián A. Herrera

    2009-01-01

    Objetivo: Describir la prevalencia del síndrome del cuidador y las características psicosociales de los cuidadores de adultos mayores discapacitados. Materiales y métodos: Se realizó un estudio piloto de casos y controles en el Valle del Cauca durante el 2003-2004 para evaluar la funcionalidad familiar (APGAR familiar), la ansiedad y depresión (escala de Goldberg), la presencia de enfermedades (cuidadores y no cuidadores), y la prevalencia del síndrome del cuidador (escala de Zarit). Resultad...

  1. INTER-DIDÁCTICA -El reto intercultural del maestro inmigrante en el Valle del Guamuéz (Putumayo, Colombia)-

    OpenAIRE

    Armero Díaz, Amanda Milena; Enríquez López, Miriam Fernanda; Osejo Ortega, Myrian Patricia; Betancourth Nastul, Wilson

    2016-01-01

    Tesis (Maestría en Educación desde la Diversidad). Universidad de Manizales. Facultad de Ciencias Sociales y Humanas, 2015 Los procesos de enseñanza-aprendizaje, a la vanguardia post-moderna, ameritan asumir una nueva perspectiva de la didáctica, demostrando en esta investigación que el componente cultural juega un papel trascendental en su transformación. El siguiente estudio surge de la premisa investigativa ¿Cómo fortalecer la identidad cultural del Valle del Guamuéz, Departam...

  2. Las necesidades de capacitación de empresarios de MIPYMES del Valle de Mexicali, México, y la demanda de capacitación de los mismos, en el semestre 2011-1

    Directory of Open Access Journals (Sweden)

    Marcela Reyes Pazos

    2012-07-01

    Full Text Available El propósito de la investigación es analizar las necesidades de capacitación de empresarios de MIPYMES (Micro, Pequeñas y Medianas Empresas del Valle de Mexicali, y la demanda de capacitación de los mismos, durante el semestre 2011-1. Esta investigación la realiza el cedem-uabc (Centro Desarrollo Empresarial de la Escuela de Ingeniería y Negocios, Guadalupe Victoria, de la Universidad Autónoma de Baja California, campus Mexicali. El método seguido fue investigación cuantitativa, con una muestra aleatoria no representativa de 469 MIPYMES encuestadas de los distintos ejidos del Valle de Mexicali. Los principales resultados obtenidos manifiestan que existe demanda de capacitación, en áreas como administración, publicidad y mercadotecnia, y ventas. Los resultados del diagnóstico de la investigación indican que sí están presentes las necesidades de capacitación por parte de la mayoría de los empresarios de las MIPYMES del Valle de Mexicali, pero muy pocos la han solicitado. Los objetivos de la investigación se lograron analizando las necesidades de capacitación y la demanda de capacitación de los empresarios.

  3. Las necesidades de capacitación de empresarios de MIPYMES del Valle de Mexicali, México, y la demanda de capacitación de los mismos, en el semestre 2011-1

    Directory of Open Access Journals (Sweden)

    Marcela Reyes Pazos

    2012-06-01

    Full Text Available El propósito de la investigación es analizar las necesidades de capacitación de empresarios de MIPYMES (Micro, Pequeñas y Medianas Empresas del Valle de Mexicali, y la demanda de capacitación de los mismos, durante el semestre 2011-1. Esta investigación la realiza el cedem-uabc (Centro Desarrollo Empresarial de la Escuela de Ingeniería y Negocios, Guadalupe Victoria, de la Universidad Autónoma de Baja California, campus Mexicali. El método seguido fue investigación cuantitativa, con una muestra aleatoria no representativa de 469 MIPYMES encuestadas de los distintos ejidos del Valle de Mexicali. Los principales resultados obtenidos manifiestan que existe demanda de capacitación, en áreas como administración, publicidad y mercadotecnia, y ventas. Los resultados del diagnóstico de la investigación indican que sí están presentes las necesidades de capacitación por parte de la mayoría de los empresarios de las MIPYMES del Valle de Mexicali, pero muy pocos la han solicitado. Los objetivos de la investigación se lograron analizando las necesidades de capacitación y la demanda de capacitación de los empresarios.

  4. Un plan de gestión para la prevención y control de la contaminación del aire por BTX (Benceno, Tolueno, Xileno) en el Área Metropolitana del Valle de Aburrá

    OpenAIRE

    Rubiano Hernández, Claudia Marcela

    2013-01-01

    Resumen: El presente trabajo desarrolla un plan de gestión para la prevención y control de la contaminación del aire por BTX (Benceno, Tolueno, Xileno) en el área metropolitana del Valle de Aburrá, el cual se considera necesario de acuerdo a los valores obtenidos en las campañas de caracterización realizadas en las zonas urbanas del valle y que evidencian niveles que sobrepasan la norma en algunos puntos de muestreo poniendo en riesgo a mediano y largo plazo la salud de los habitantes de la r...

  5. VS of the uppermost crust structure of the Campi Flegrei caldera (southern Italy) from ambient noise Rayleigh wave analysis

    Science.gov (United States)

    Costanzo, M. R.; Nunziata, C.; Strollo, R.

    2017-11-01

    Shear wave velocities (VS) are defined in the uppermost 1-2 km of the Campi Flegrei caldera through the non-linear inversion of the group velocity dispersion curves of fundamental-mode Rayleigh waves extracted from ambient noise cross-correlations between two receivers. Noise recordings, three months long, at 12 seismic stations are cross-correlated between all couples of stations. The experiment provided successful results along 54 paths (inter-stations distance), of which 27 sampled a depth > 1 km. VS contour lines are drawn from 0.06 km b.s.l. to 1 km depth b.s.l. and show difference between the offshore (gulf of Pozzuoli and coastline) and the onshore areas. At 0.06 km b.s.l., the gulf of Pozzuoli and the coastline are characterized by VS of 0.3-0.5 km/s and of 0.5-0.7 km/s, respectively. Such velocities are typical of Neapolitan pyroclastic soils and fractured or altered tuffs. The inland shows VS in the range 0.7-0.9 km/s, typical of Neapolitan compact tuffs. Velocities increase with depth and, at 1 km depth b.s.l., velocities lower than 1.5 km/s are still present in the gulf and along the coastline while velocities higher than 1.9 km/s characterize the eastern sector (grossly coincident with the Neapolitan Yellow Tuff caldera rim), the S. Vito plain and the area between Solfatara and SW of Astroni. Such features are much more evident along two cross-sections drawn in the offshore and onshore sectors by integrating our VS models with literature data. Our models join previous noise cross-correlation studies at greater scale at depths of 0.7-0.8 km, hence the picture of the Campi Flegrei caldera is shown up to a depth of 15 km. VS of about 1.7 km/s, corresponding to compression velocities (VP) of about 3 km/s (computed by using the VP/VS ratio resulted in the inversion), are found at depths of 1.1 km, in the centre of the gulf of Pozzuoli, and at a depth of about 0.7 km b.s.l. onshore. An increment of VS velocity ( 1.9-2.0 km/s) is locally observed onshore

  6. Qu’elle était verte ma vallée

    Directory of Open Access Journals (Sweden)

    Hervé Nicolle

    2014-07-01

    Full Text Available Le présent texte présente certaines des conclusions d’une étude conduite dans le district de Deh Sabz au Nord de la capitale Afghane, à l’automne 2011. Alors qu’un vaste projet urbanistique doit voir le jour dans les prochaines décennies sur le territoire de Deh Sabz, autrefois « vallée verte » de Kaboul, les nomades en transit dans le district voient leur genre de vie traditionnel profondément remis en cause. Les changements radicaux survenus depuis quarante ans, les discours opportunistes des prédateurs politiques locaux, l’alternance des sécheresses et inondations, ou la réduction des terres de pâture contribuent à accélérer un phénomène de sédentarisation – doublé d’une marginalisation socio-économique accrue. Cette perte d’identité des nomades Kuchi, parce qu’elle ne s’accompagne d’aucune contrepartie, comporte un risque politique important à l’heure où le pays doit faire face à une transition politique aux contours incertains, ainsi qu’à une criminalité et une insécurité accrues.

  7. A geochemical and geophysical reappraisal to the significance of the recent unrest at Campi Flegrei caldera (Southern Italy)

    Science.gov (United States)

    Moretti, Roberto; De Natale, Giuseppe; Troise, Claudia

    2017-04-01

    Volcanic unrest at calderas involve complex interaction between magma, hydrothermal fluids and crustal stress and strain. Campi Flegrei caldera (CFc), located in the Naples (Italy) area and characterised by the highest volcanic risk on Earth for the extreme urbanisation, undergoes unrest phenomena involving several meters of uplift and intense shallow micro-seismicity since several decades. Despite unrest episodes display in the last decade only moderate ground deformation and seismicity, current interpretations of geochemical data point to a highly pressurized hydrothermal system. We show that at CFc, the usual assumption of vapour-liquid coexistence in the fumarole plumes leads to largely overestimated hydrothermal pressures and, accordingly, interpretations of elevated unrest. By relaxing unconstrained geochemical assumptions, we infer an alternative model yielding better agreement between geophysical and geochemical observations. The model reconciles discrepancies between what observed 1) for two decades since the 1982-84 large unrest, when shallow magma was supplying heat and fluids to the hydrothermal system, and 2) in the last decade. Compared to the 1980's unrest, the post-2005 phenomena are characterized by much lower aquifers overpressure and magmatic involvement, as indicated by geophysical data and despite large changes in geochemical indicators. Our interpretation points out a model in which shallow sills, intruded during 1969-1984, have completely cooled, so that fumarole emissions are affected now by deeper, CO2-richer, magmatic gases producing a relatively modest heating and overpressure of the hydrothermal system. Our results do have important implications on the short-term eruption hazard assessment and on the best strategies for monitoring and interpreting geochemical data.

  8. La formación racial y resignificación de la justicia social en el Valle del Chota

    OpenAIRE

    Zambrano Murillo, María Giulianna

    2010-01-01

    El objetivo de este trabajo es analizar la movilización social afroecuatoriana desde lo local y, para ello, se concentrará en el estudio de las organizaciones sociales en el Valle del Chota a través de la historia. La reducción del alcance responde a la escasa bibliografía que documenta las dinámicas locales de las organizaciones, especialmente cuando pasan a formar parte de un movimiento nacional, y también a la necesidad de recuperar la historia y las necesidades específicas de las comunida...

  9. La institucionalidad turística y el desarrollo de dos productos turísticos del valle del Colca

    OpenAIRE

    Aronés Ochoa, Cedy Calissa

    2014-01-01

    Universidad Nacional Agraria La Molina. Escuela de Posgrado. Maestría en Ecoturismo La presente tesis de maestría aborda el estudio de dos productos turísticos en el Valle del Colca (Caylloma, Arequipa – Perú), a partir de la observación de los fenómenos socio políticos suscitados entre el 2002 – 2012. Con el estudio se busca identificar las principales características de dos productos turísticos distintivos del destino Colca, analizar la construcción de la institucionalidad turística en e...

  10. CÓMO LLEGAN A LA DEFINICIÓN DE LA ESTRATEGIA LAS EMPRESAS LOCALIZADAS EN EL VALLE DE ABURRÁ

    OpenAIRE

    Alejandro, Ramos

    2008-01-01

    Este artículo está enfocado a entender las variables y determinantes de las ideas sobre cómo llegan a la estrategia expresadas por personas que trabajan en empresas localizadas en el valle de Aburrá. El método empleado para realizar la investigación que soporta este artículo fue de carácter exploratorio con enfoque cualitativo, recolectando la información mediante un trabajo de campo por medio de una guía semiestructurada de preguntas abiertas, para posteriormente hacer el análisis y observac...

  11. Read-through transcript from NM23-H1 into the neighboring NM23-H2 gene encodes a novel protein, NM23-LV

    NARCIS (Netherlands)

    Valentijn, Linda J.; Koster, Jan; Versteeg, Rogier

    2006-01-01

    NM23-H1 and NM23-H2 are neighboring genes on chromosome 17q. They encode nucleoside diphosphate kinases that have additional roles in signal transduction, transcription, and apoptosis. NM23-H1 expression is a strong marker for prognosis and metastatic behavior in many tumor types. A new

  12. Determination of elements in the atmosphere of Valle de Toluca by Neutron Activation (July 1992 - April 1993)

    International Nuclear Information System (INIS)

    Garcia S, I.

    1994-01-01

    The purpose of this study is to continue with the environmental monitoring program of Valle de Toluca by means of the Neutron Activation Analysis and atomic absorption techniques. The analytical results corresponding to the period of July 1992 to April 1993, and the analyzed elements by Neutron Activation were Na, V, Br, Al and Mn, while Cr and Pb were analyzed by Atomic Absorption Spectroscopy. Since the study is a joint project with the Facultad de Quimica de la Universidad Autonoma del Estado de Mexico, the purpose is to continue with this type of chemical analysis. (Author)

  13. Grafismo mueble en el Valle de Côa (Vila Nova de Foz Côa, Portugal: la estación arqueológica de Fariseu

    Directory of Open Access Journals (Sweden)

    Marcos GARCÍA DIEZ

    2013-05-01

    Full Text Available El repertorio de arte mueble paleolítico en territorio portugués es muy reducido. Durante los trabajos arqueológicos realizados, con carácter de urgencia en diciembre de 1999, en la estación de Fariseu (Vila Nova de Foz Côa, Portugal se localizaron dos plaquetas de esquisto en contexto estratigráfico. A falta de dataciones radiométricas de los niveles arqueológicos, y sobre la base del estudio de las evidencias líticas, la primera de ellas, con un rico repertorio temático, se adscribe a momentos finales del Magdaleniense. La segunda, con sólo una figura zoomorfa, se relaciona con ocupaciones del Magdaleniense antiguo o Protosolutrense. Se realiza una valoración de las evidencias dentro del contexto peninsular, prestando especial atención a la vertiente mediterránea, y se relacionan con el grafismo rupestre del valle de Côa, aportando así elementos de inserción cronológica para caracterizar el amplio repertorio rupestre del valle de Côa.

  14. First principles study on the interfacial properties of NM/graphdiyne (NM = Pd, Pt, Rh and Ir): The implications for NM growing

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Zhansheng; Li, Shuo; Lv, Peng [College of Physics and Electronic Engineering, Henan Normal University, Xinxiang 453007 (China); He, Chaozheng, E-mail: hecz2013@nynu.edu.cn [College of Physics and Electronic Engineering, Nanyang Normal University, Nanyang 473061 (China); Ma, Dongwei [School of Physics, Anyang Normal University, Anyang 455000 (China); Yang, Zongxian, E-mail: yzx@henannu.edu.cn [College of Physics and Electronic Engineering, Henan Normal University, Xinxiang 453007 (China); Collaborative Innovation Center of Nano Functional Materials and Applications, Kaifeng (China)

    2016-01-01

    Graphical abstract: - Highlights: • The NM adatoms belong to embedded adsorption in 18C-hexagon of GDY. • The Rh and Ir/GDY can be applied to single metal catalysts or sensors. • A simple linear relationship between E{sub e-ads} and E{sub b} is presented. • The linear relationship can be used in the noble metal modified GDY. - Abstract: Based on the dispersion-corrected density functional calculations (DFT-D), we systematically studied the adsorption of noble metals (NM), Pd, Pt, Rh and Ir, on graphdiyne (GDY). We present a systematic study on the geometry, embedded adsorption energy and electronic structure of four different adatoms adsorbed on the GDY. The strong interaction between the NM adatoms and the GDY substrate is found with the NM embedded in the 18C-hexagon of the GDY. We investigated the mobility of the NM adatoms on the GDY, and found that the mobility barrier energy increases along with the increasing of the embedded adsorption energy. We present the NM adatoms growth of high concentrations on the GDY. Upon the analysis of the electronic structure and the frontier molecular orbitals, Rh and Ir adatoms of low concentrations (about 1.37 at%) on the GDY have the potential to be applied as single metal catalysts or gas molecule sensors.

  15. Lista anotada y clave para las ranas (género Eleutherodactylus chocoanas del Valle del Cauca, y apuntes sobre las especies de la Cordillera Occidental adyacente

    Directory of Open Access Journals (Sweden)

    Lynch John Douglas

    1999-11-01

    Full Text Available Twenty-three species of the genus Eleutherodactylus are reported fram 24 localities in the western lowlands of Valle del Cauca, Colombia, with notes on their identificacion and distributions. Up to 16 species have been taken from a single site. The cloud forest fauna of  Eleutherodactylus found on the Cordillera Occidental above the drainages of the Anchicayá, Cajambre, Calima, and Dagua rivers consists of 24 species with up to 18 species being found in a single site.Se da información sobre la identificación y las distribuciones de 23 especies del género Eleutherodactylus de 24 sitios de las tierras bajas del occidente del Valle del Cauca, Colombia. Hasta 16 especies fueron registradas del mismo sitio. La fauna de Eleutherodactylus de los bosques nublados de la Cordillera Occidental en los drenajes de los ríos Anchicayá, Cajambre, Calima, y Dagua consta de 24 especies, con hasta 18 encontradas en un mismo sitio.

  16. Comparison of 193 nm and 308 nm laser liquid printing by shadowgraphy imaging

    Energy Technology Data Exchange (ETDEWEB)

    Palla-Papavlu, A., E-mail: apalla@nipne.ro [National Institute for Lasers, Plasma and Radiation Physics, P.O. Box MG-36, Magurele, RO-077125 Bucharest (Romania); Shaw-Stewart, J. [EMPA, Swiss Federal Laboratories for Materials Testing and Research, Laboratory for Functional Polymers, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Paul Scherrer Institute, General Energy Research Department, 5232 Villigen PSI (Switzerland); Mattle, T. [Paul Scherrer Institute, General Energy Research Department, 5232 Villigen PSI (Switzerland); Dinca, V. [National Institute for Lasers, Plasma and Radiation Physics, P.O. Box MG-36, Magurele, RO-077125 Bucharest (Romania); Lippert, T.; Wokaun, A. [Paul Scherrer Institute, General Energy Research Department, 5232 Villigen PSI (Switzerland); Dinescu, M. [National Institute for Lasers, Plasma and Radiation Physics, P.O. Box MG-36, Magurele, RO-077125 Bucharest (Romania)

    2013-08-01

    Over the last years laser-induced forward transfer has emerged as a versatile and powerful tool for engineering surfaces with active compounds. Soft, easily damageable materials can be transferred using a triazene polymer as a sacrificial layer which acts as a pressure generator and at the same time protects the material from direct laser irradiation. To understand and optimize the transfer process of biomolecules in liquid solution by using an intermediate triazene polymer photosensitive layer, shadowgraphy imaging is carried out. Two laser systems i.e. an ArF laser operating at 193 nm and a XeCl laser operating at 308 nm are applied for the transfer. Solutions with 50% v/v glycerol concentration are prepared and the influence of the triazene polymer sacrificial layer thickness (60 nm) on the deposits is studied. The shadowgraphy images reveal a pronounced difference between laser-induced forward transfer using 193 nm or 308 nm, i.e. very different shapes of the ejected liquid.

  17. Compact corner-pumped Nd:YAG/YAG composite slab 1319 nm/1338 nm laser

    International Nuclear Information System (INIS)

    Liu, H; Gong, M; Wushouer, X; Gao, S

    2010-01-01

    A corner-pumped type is a new pumping type in the diode-pumped solid-state lasers, which has the advantages of high pump efficiency and favorable pump uniformity. A corner-pumped Nd:YAG/YAG composite slab continuous-wave 1319 nm/1338 nm dual-wavelength laser is first demonstrated in this paper. When the cavity length is 25 mm, the maximal output power is up to 7.62 W with a slope efficiency of 16.6% and an optical-to-optical conversion efficiency of 17%. The corresponding spectral line widths of 1319 nm laser and 1338 nm laser are 0.11 and 0.1 nm, respectively. The short-term instability of the output power is better than 1% when the pumping power is 39.5 W. The experimental results show that a corner-pumped type is a kind of feasible schedules in the design of diode-pumped solid-state 1.3 μm lasers with low or medium output powers

  18. Surface morphology of caldera-forming eruption deposits revealed by lidar mapping of Crater Lake National Park, Oregon- Implications for emplacement and surface modification

    Science.gov (United States)

    Robinson, Joel E.; Bacon, Charles R.; Major, Jon J.; Wright, Heather M.; Vallance, James W.

    2017-01-01

    Large explosive eruptions of silicic magma can produce widespread pumice fall, extensive ignimbrite sheets, and collapse calderas. The surfaces of voluminous ignimbrites are rarely preserved or documented because most terrestrial examples are heavily vegetated, or severely modified by post-depositional processes. Much research addresses the internal sedimentary characteristics, flow processes, and depositional mechanisms of ignimbrites, however, surface features of ignimbrites are less well documented and understood, except for comparatively small-volume deposits of historical eruptions. The ~7,700 calendar year B.P. climactic eruption of Mount Mazama, USA vented ~50 km3 of magma, deposited first as rhyodacite pumice fall and then as a zoned rhyodacite-to-andesite ignimbrite as Crater Lake caldera collapsed. Lidar collected during summer 2010 reveals the remarkably well-preserved surface of the Mazama ignimbrite and related deposits surrounding Crater Lake caldera in unprecedented detail despite forest cover. The ±1 m lateral and ±4 cm vertical resolution lidar allows surface morphologies to be classified. Surface morphologies are created by internal depositional processes and can point to the processes at work when pyroclastic flows come to rest. We describe nine surface features including furrow-ridge sets and wedge-shaped mounds in pumice fall eroded by high-energy pyroclastic surges, flow- parallel ridges that record the passage of multiple pyroclastic flows, perched benches of marginal deposits stranded by more-mobile pyroclastic-flow cores, hummocks of dense clasts interpreted as lag deposit, transverse ridges that mark the compression and imbrication of flows as they came to rest, scarps indicating ignimbrite remobilization, fields of pit craters caused by phreatic explosions, fractures and cracks caused by extensional processes resulting from ignimbrite volume loss, and stream channels eroded in the newly formed surface. The nine morphologies presented

  19. Coleópteros acuáticos y semiacuáticos del Parque Provincial Salto Encantado y Valle del Cuñá Pirú (Misiones, Argentina Aquatic and semiaquatic Coleoptera from Salto Encantado y Valle del Cuñá Pirú Provincial Park (Misiones, Argentina

    Directory of Open Access Journals (Sweden)

    Liliana A. Fernández

    2008-12-01

    Full Text Available Se presentan los resultados de la recolección de coleópteros acuáticos y semiacuáticos del Parque Provincial Salto Encantado y Valle del Cuñá Pirú, con el objeto de contribuir al conocimiento de la biodiversidad del área protegida mencionada, de la provincia de Misiones. Los sitios de muestreo incluyeron ambientes lóticos y lénticos. Se registraron 74 especies de coleópteros, distribuidas en 44 géneros y 14 familias: Haliplidae, Noteridae, Dytiscidae, Gyrinidae, Hydrochidae, Hydrophilidae, Hydraenidae, Staphylinidae, Scirtidae, Psephenidae, Limnichidae, Lutrochidae, Dryopidae y Elmidae. Se mencionan nuevas citas para la provincia y para la Argentina, así como la presencia de especies nuevas para la ciencia.This paper presents a list of aquatic and semiaquatic Coleoptera collected during a biodiversity study carried out in Salto Encantado and Valle del Cuñá Pirú Provincial Park. This study aims to improve the knowledge of this protected area located in Misiones Province. Permanent and semi-permanent lotic and lentic habitats were sampled. Seventy-four species of beetles in 44 genera and 14 families were recorded: Haliplidae, Noteridae, Dytiscidae, Gyrinidae, Hydrochidae, Hydrophilidae, Hydraenidae, Staphylinidae, Scirtidae, Psephenidae, Limnichidae, Lutrochidae, Dryopidae and Elmidae. New records for the province and for Argentina are listed, and the presence of new species is mentioned.

  20. Picosecond laser texturization of mc-silicon for photovoltaics: A comparison between 1064 nm, 532 nm and 355 nm radiation wavelengths

    Energy Technology Data Exchange (ETDEWEB)

    Binetti, Simona [Department of Materials Science and Milano-Bicocca Solar Energy Research Center (MIB-SOLAR), University of Milano-Bicocca, Via Cozzi 55, 20125 Milano (Italy); Le Donne, Alessia, E-mail: alessia.ledonne@mater.unimib.it [Department of Materials Science and Milano-Bicocca Solar Energy Research Center (MIB-SOLAR), University of Milano-Bicocca, Via Cozzi 55, 20125 Milano (Italy); Rolfi, Andrea [Department of Materials Science and Milano-Bicocca Solar Energy Research Center (MIB-SOLAR), University of Milano-Bicocca, Via Cozzi 55, 20125 Milano (Italy); Jäggi, Beat; Neuenschwander, Beat [Bern University of Applied Sciences, Engineering and Information Technology, Institute for Applied Laser, Photonics and Surface Technologies ALPS, Pestalozzistrasse 20, CH-3400 Burgdorf (Switzerland); Busto, Chiara [ENI Spa, Via Giacomo Fauser, 4, 28100 Novara (Italy); Frigeri, Cesare [CNR-IMEM Institute, Parco Area Delle Scienze 37/A, Fontanini, 43010 Parma (Italy); Scorticati, Davide; Longoni, Luca; Pellegrino, Sergio [Laserpoint Srl, Via Della Burrona 51, 20090 Vimodrone, Milano (Italy)

    2016-05-15

    Highlights: • Self-organized surface structures were produced by picosecond laser pulses on mc-Si. • Three laser wavelengths were used which effectively reduce Si reflectivity up to 8%. • The subsurface damage induced by the three lasers was studied in detail. • μ-Raman, PL and TEM proved that UV laser provides the lowest subsurface damage. • UV laser induced damage is located above the depletion region of the p–n junction. - Abstract: Self-organized surface structures were produced by picosecond laser pulses on multi-crystalline silicon for photovoltaic applications. Three different laser wavelengths were employed (i.e. 1064 nm, 532 nm and 355 nm) and the resulting morphologies were observed to effectively reduce the reflectivity of the samples after laser irradiation. Besides, a comparative study of the laser induced subsurface damage generated by the three different wavelengths was performed by confocal micro-Raman, photoluminescence and transmission electron microscopy. The results of both the structural and optical characterization showed that the mc-Si texturing performed with the laser at 355 nm provides surface reflectivity between 11% and 8% over the spectral range from 400 nm to 1 μm, while inducing the lowest subsurface damage, located above the depletion region of the p–n junction.

  1. El cuaternario del Valle Inferior del Manzanares (Cuenca de Madrid, España

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    Silva, P. G.

    2003-08-01

    the water and sediment supply during the end of cold periods with relevant neotectonic and karstic activity, feedback by significant intrabasinal headward erosion processes from the late Middle Pleistocene.Se analiza el tramo Inferior del Manzanares entre Villaverde y su desembocadura en el río Jarama. En este tramo, el valle es de carácter asimétrico con desarrollo de escarpes en Yesos (ea. 60 m en su margen izquierda y de terrazas complejas en su margen derecha. Dentro de ellas la que domina la geomorfología del sector es un nivel de terraza complejo (engrosado que denominamos TCMZ (+ 16-22 m. Se encuentra constituido por al menos cinco secuencias fluviales (Mz de tipo meandriforme. Sobre ellas se solapan a doble vertiente niveles mixtos (Mx desde los + 15 a los + 8 m que poseen un carácter (más braided. En la arquitectura de la TCMZ participan muy significativamente aportes laterales procedentes de los tributarios (Butarque y Culebro, de los relieves marginales (escarpes en yesos y de los propios sistemas de terrazas (derrames de escarpes. La TCMZ es el nivel más alto en este sector sobre el que, además, se instala la propia divisoria del Valle en este sector, constituyendo este hecho el carácter más anómalo del valle. Todos estos caracteres poco usuales son resultado directo de la respuesta del sistema fluvial al proceso de captura que sufrió por parte del Jarama durante el Pleistoceno medio. Los contenidos faunísticos y líticos de la TCMZ permiten situar su desarrollo entre los OIS 10 (? al 5. Una manifiesta crisis paleosísmica a comienzos del OIS 5 acompaña al primer episodio de disección importante en el valle después del proceso de Captura. Las faunas frías e industrias musterienses de los niveles Mx permiten ubicar su desarrollo entre el OIS 4 y 3. En cualquier caso hay que considerar que los episodios de cut & fill que han modelado el paisaje fluvial durante el Pleistoceno superior difícilmente responden a los cambios eustáticos que

  2. Red comunitaria para la gestión ambiental en el Valle de Aburrá

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    Toro Maria Isabel

    2011-11-01

    Full Text Available Cuando se hace referencia al cuidado y protección del ambiente, uno de los aspectos de tener en cuenta es la vulnerabilidad social, puesto que es más vulnerable una población sin ningún tipo de organización, sin cohesión ni gestión comunitaria, que una com unidad organizada para protegerse y cuidarse y donde la mayoría participa, toma decisiones y actúa para su desarrollo. Para realizar una coordinación entre las organizaciones sociales existentes que trabajan por la protección y preservación de las condiciones ambientales de su territorio, se hace necesario la unificación de los papeles y perfiles de sus integrantes, sus objetivos, estrategias, proyectos e intervenciones en la búsqueda del bien común. Por lo anterior, el Área Metropolitana del Valle de Aburrá con la Universidad EAFIT diseñó e implementó una Red Comunitaria para la Gestión Ambiental, como un sistema organizado, abierto y participativo que fomenta los principios de voluntad, mutualidad, solidaridad, diversidad, tolerancia, comunicación, respeto, sentido de pertenencia y trabajo en equipo. La Red Comunitaria de Comités Ambientales del valle de Aburrá busca entonces retomar los antecedentes existentes en el campo de la preparación y participación comunitaria para la prevención y atención de emergencias y desastres, como los son las experiencias de los municipios de Medellín y Bello. Esta red tiene como fundamento los lineam ientos necesarios para articular las acciones, estrategias y com petencias de sus integrantes y las de aquellas personas que representan a las autoridades ambientales, administraciones municipales y organismos de socorro, que son pilares de apoyo dentro de una estructura integral para un grupo especializado en la problemática ambiental y de gestión del riesgo.

  3. The Evolution of Juventae Chasma, Valles Marineris, Mars: Progressive Collapse and Sedimentation

    Science.gov (United States)

    Fueten, F.; Novakovic, N.; Stesky, R.; Flahaut, J.; Hauber, E.; Rossi, A. P.

    2017-11-01

    Juventae Chasma is an isolated chasm located north of the interconnected chasms within Valles Marineris. It contains four separate interior layered deposit (ILD) mounds. We have combined layer measurements, as well as mineralogical data of the mounds with topographic data of the remaining chasm and the surrounding plateau. Our observations indicate that the chasm underwent a complex geological history. We suggest that individual ILD mounds are not contemporaneous with each other and a series of progressive collapses enlarged an initially smaller chasm to its current shape. ILDs were deposited in a lacustrine setting, and the time of ILD deposition was limited. Basin collapse and chasm enlargement continued beyond the time of ILD deposition and thus were not driven by sediment load. Glacial processes appear to have played a role in the late, postlacustrine history of the chasm. We present a simplified model that highlights some of the complexity of the chasm evolution, but acknowledge that the true history is undoubtedly more complicated.

  4. Magma mixing and the generation of isotopically juvenile silicic magma at Yellowstone caldera inferred from coupling 238U–230Th ages with trace elements and Hf and O isotopes in zircon and Pb isotopes in sanidine

    Science.gov (United States)

    Stelten, Mark E.; Cooper, Kari M.; Vazquez, Jorge A.; Reid, Mary R.; Barfod, Gry H.; Wimpenny, Josh; Yin, Qing-Zhu

    2013-01-01

    The nature of compositional heterogeneity within large silicic magma bodies has important implications for how silicic reservoirs are assembled and evolve through time. We examine compositional heterogeneity in the youngest (~170 to 70 ka) post-caldera volcanism at Yellowstone caldera, the Central Plateau Member (CPM) rhyolites, as a case study. We compare 238U–230Th age, trace-element, and Hf isotopic data from zircons, and major-element, Ba, and Pb isotopic data from sanidines hosted in two CPM rhyolites (Hayden Valley and Solfatara Plateau flows) and one extracaldera rhyolite (Gibbon River flow), all of which erupted near the caldera margin ca. 100 ka. The Hayden Valley flow hosts two zircon populations and one sanidine population that are consistent with residence in the CPM reservoir. The Gibbon River flow hosts one zircon population that is compositionally distinct from Hayden Valley flow zircons. The Solfatara Plateau flow contains multiple sanidine populations and all three zircon populations found in the Hayden Valley and Gibbon River flows, demonstrating that the Solfatara Plateau flow formed by mixing extracaldera magma with the margin of the CPM reservoir. This process highlights the dynamic nature of magmatic interactions at the margins of large silicic reservoirs. More generally, Hf isotopic data from the CPM zircons provide the first direct evidence for isotopically juvenile magmas contributing mass to the youngest post-caldera magmatic system and demonstrate that the sources contributing magma to the CPM reservoir were heterogeneous in 176Hf/177Hf at ca. 100 ka. Thus, the limited compositional variability of CPM glasses reflects homogenization occurring within the CPM reservoir, not a homogeneous source.

  5. Movilidad Espacial, Ocupación y Empleo en el Valle Inferior del Río Chubut Spatial mobility, Occupation and Employment in the Inferior Valley of the River Chubut

    Directory of Open Access Journals (Sweden)

    M. Marcela Crovetto

    2011-12-01

    Full Text Available Desde una perspectiva que propone una serie de críticas a la tipología dicotómica de clasificación demográfica del espacio habitado, rural y urbano, se ha indagado sobre las formas que adquiere la movilidad espacial cotidiana en relación al empleo y a la ocupación en el Valle Inferior del Río Chubut -patagonia argentina-, atendiendo a una situación especial de movilidad espacial cotidiana como es la referida a la producción de cerezas en el Valle. Se utilizaron fuentes secundarias estadísticas, históricas y documentales en articulación con la construcción de datos primarios mediante relevamientos operados por distintas técnicas. Fundamentalmente se aplicó una encuesta a hogares (200 casos de barrios periféricos de las localidades involucradas en el Valle Inferior del Río Chubut El centro del ejercicio de la investigación estuvo en contraponer los resultados de una encuesta realizada en campo de acuerdo tanto a la clasificación clásica de la zona de residencia (rural o urbana como a una propuesta alternativa para la investigación. Así se evaluaron los matices escondidos dentro de las homogeneizantes ideas de rural y urbano, sintetizadas por la cantidad de habitantes -en Argentina con 2000 o más se considera un espacio urbano, con menos un espacio rural- observándose, especialmente, que muchas trayectorias cotidianas de actores sociales considerados clásicamente urbanos se acercaban mucho a las de los actores de las zonas rurales.From a perspective that proposes a number of criticisms of the dichotomous typology of demographic classification of living space, rural and urban, has inquired about the forms that everyday spatial mobility in relation to employment in the Valle Inferior del Río Chubut - Patagonia-Argentina, following a special situation of everyday spatial mobility as that concerning the production of cherries in the Valley. Were used statistics, historical and documentary in coordination with the construction

  6. Factores psicosociales que promueven la resiliencia en los niños trabajadores del municipio de Roldanillo-Valle del Cauca

    OpenAIRE

    Victoria Aguilar, Mariela

    2011-01-01

    Tesis (Maestría en Desarrollo Infantil). Universidad de Manizales. Facultad de Ciencias Sociales y Humanas, 2011 El resultado de la investigación, da respuesta al interrogante ¿Cuáles son los factores psicosociales que promueven la resilencia en los niños trabajadores del municipio de Roldanillo-Valle del Cauca? Para obtener esta información se identificaron factores de riesgo y factores protectores presentes en los niños trabajadores que se dedican específicamente a labores comerciales. E...

  7. Correlación de variables macroclimáticas del Océano Pacífico con los caudales en los ríos interandinos del Valle del Cauca (Colombia

    Directory of Open Access Journals (Sweden)

    Yesid Carvajal

    2014-06-01

    Full Text Available Los fenómenos climáticos sobre los océanos ejercen gran influencia sobre la hidroclimatología del valle del río Cauca (Colombia, en especial el evento "El Niño Oscilación Sur" (ENOS, que es responsable de la variabilidad climática en escalas de tiempo que van desde meses hasta décadas. Debido a esta dependencia, se estudió la correlación entre 8 variables indicadoras del clima en los Océanos Pacífico y Atlántico con los caudales medios mensuales de 8 ríos del valle del río Cauca. Las series cubren un período promedio de 40 años 1957-1997. Los resultados muestran las variaciones regionales de la situación hidrológica del valle del río Cauca respecto a las variables macroclimáticas. Los coeficientes de correlación indican que las variables que presentan mayor asociación con los caudales analizados son en su orden: Las temperaturas de la superficie del mar en las regiones Niño 3, Niño 3-4, Niño 4 Y SOl, mientras en el Atlántico, las mejores correlaciones las presentan: la Temperatura en el Trópico, en el Atlántico Norte (NATL y Atlántico Sur (SATL respectivamente.

  8. Fracciones de fósforo en suelos del Valle del Cauca con diferentes sistemas de cultivo de café Phosphorus fractions in soils of the Valle del Cauca under different coffee crop systems

    Directory of Open Access Journals (Sweden)

    Diana Milena Mejía Umaña

    2011-07-01

    Full Text Available El trabajo tuvo como objetivo evaluar la influencia de los sistemas de cultivo de café: orgánico, convencional y orgánico-mineral, sobre las fracciones de fósforo (P en suelos del departamento del Valle del Cauca, Colombia. Las mediciones por fraccionamiento secuencial reducido se hicieron en el Laboratorio de Suelos del Centro Internacional de Agricultura Tropical (CIAT. El análisis estadístico se ajustó a un modelo de diseño completamente aleatorio en un arreglo en parcelas divididas con tres tratamientos y tres repeticiones. Los resultados mostraron que los contenidos de las fracciones orgánicas de P disponible y P moderadamente disponible variaron (P This study was conducted in the department of Valle del Cauca (Colombia coffee growing zone to evaluate the response of planting coffee under different cropping systems: organic, conventional and organicmineral, on soil phosphorus fractions with volcanic influence. Sequential fractionation methodology adapted by the International Center of Tropical Agriculture was used. The statistical analysis consisted of a Complete Randomized Block Design under a split plot arrangement with three treatments and three replications. The results showed that contents of the organic fraction of available P and the moderately available P showed significant differences among the systems in which organic and conventional management was included, the conventional system had the lowest values. The organic-mineral system showed the highest contents of organic and inorganic phosphorus and the conventional system showed the lowest for these fractions of P. For the non available P fraction, it was found that organic systems had higher P content than the conventional system and, the organic-mineral system showed significant differences with respect to the rest. The total P showed a similar pattern to the fractions described. The low content in the conventional system can be explained by specific aspects of

  9. Une approche écosanté pour le contrôle de la fièvre de la vallée du ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    17 août 2016 ... La fièvre de la vallée du Rift est une maladie grave qui se transmet par la piqûre d'un moustique qui infecte l'être humain, le bétail et les animaux sauvages. De plus, les êtres humains peuvent contracter la maladie par tout contact avec des animaux infectés. La maladie s'est répandue dans toute l'Afrique ...

  10. Evolution of silicic magmas in the Kos-Nisyros volcanic center: cycles associated with caldera collapse

    Science.gov (United States)

    Ruprecht, J. S.; Bachmann, O.; Deering, C. D.; Huber, C.; Skopelitis, A.; Schnyder, C.

    2010-12-01

    Multiple eruptions of silicic magma (dacite and rhyolites) occurred over the last ~ 3 My in the Kos-Nisyros volcanic center (eastern Aegean sea). Over the course of this period, magmas have changed from hornblende-biotite rich units with low eruption temperatures (≤750-800 °C; Kefalos and Kos units) to hotter (>800-850 °C), pyroxene-bearing units (Nisyros units) and are transitioning back to colder magmas (Yali units). Using bulk-rock compositions, mineral chemistry, and zircon Hf isotopes, we show that the two different types of silicic magmas followed the same differentiation trend; they all evolved by crystal fractionation (and minor assimilation) from parents with intermediate compositions characterized by high Sr/Y and low Nb content, following a wet, high oxygen fugacity liquid line of descent typical of subduction zones. As the transition between the Kos-Kefalos and Nisyros-type magmas occurred immediately and abruptly after the major caldera collapse in the area (the 161 ky Kos Plateau Tuff; KPT), we suggest that the efficient emptying of the magma chamber during the KPT drew most of the eruptible magma out and partly froze the silicic magma source zone in the upper crust due to rapid unloading, decompression and resulting crystallization. Therefore, the system had to reinstate a shallow silicic production zone from more mafic parents, recharged at temperatures typically around 850-900 °C from the mid to lower crust. The first silicic eruptions evolving from these parents after the caldera collapse (Nisyros units) were thus slightly hotter and less evolved than the Kefalos-Kos package. However, with time, the upper crustal intermediate mush grew and cooled, leading to interstitial melt compositions reaching again the highly-evolved, cold state that prevailed prior to the Kefalos-Kos. The recent (albeit not precisely dated) eruption of the high-SiO2 rhyolite of Yali suggests that another large, potentially explosive magma chamber is presently building

  11. Evaluación de la eficiencia de remoción de material particulado y dióxido de azufre (so2) en un lavador tipo venturi para una caldera que emplea carbón como combustible

    OpenAIRE

    Jiménez Riaño, Quelver Yesid

    2012-01-01

    El aporte de las emisiones industriales a la contaminación del aire de Bogotá es significativo y, dentro de las industrias, aquellas que usan carbón como fuente de combustible para la generación de vapor en calderas son las que mayor impacto negativo tiene en la calidad del aire de la ciudad. En este trabajo se llevó a cabo la evaluación de las variables de operación de un sistema de control de emisiones atmosféricas para una caldera industrial a carbón. Se diseño, construyó y puso en marcha ...

  12. Late Quaternary eruption of the Ranau Caldera and new geological slip rates of the Sumatran Fault Zone in Southern Sumatra, Indonesia

    Science.gov (United States)

    Natawidjaja, Danny Hilman; Bradley, Kyle; Daryono, Mudrik R.; Aribowo, Sonny; Herrin, Jason

    2017-12-01

    Over the last decade, studies of natural hazards in Sumatra have focused primarily on great earthquakes and associated tsunamis produced by rupture of the Sunda megathrust. However, the Sumatran Fault and the active volcanic arc present proximal hazards to populations on mainland Sumatra. At present, there is little reliable information on the maximum magnitudes and recurrence intervals of Sumatran Fault earthquakes, or the frequency of paroxysmal caldera-forming (VEI 7-8) eruptions. Here, we present new radiocarbon dates of paleosols buried under the voluminous Ranau Tuff that constrain the large caldera-forming eruption to around 33,830-33,450 calender year BP (95% probability). We use the lateral displacement of river channels incised into the Ranau Tuff to constrain the long-term slip rate of two segments of the Sumatran Fault. South of Ranau Lake, the Kumering segment preserves isochronous right-lateral channel offsets of approximately 350 ± 50 m, yielding a minimum slip rate of 10.4 ± 1.5 mm/year for the primary active fault trace. South of Suoh pull-apart depression, the West Semangko segment offsets the Semangko River by 230 ± 60 m, yielding an inferred slip rate of 6.8 ± 1.8 mm/year. Compared with previous studies, these results indicate more recent high-volume volcanism in South Sumatra and increased seismic potency of the southernmost segments of the Sumatran Fault Zone.

  13. Las temperaturas del territorio que se extiende desde el Cantábrico Oriental al Valle del Ebro durante el periodo internacional 1961-90

    Directory of Open Access Journals (Sweden)

    Javier M. Pejenaute Goñi

    2001-01-01

    Full Text Available El presente articulo tiene por objeto el estudio de las temperaturas en el territorio comprendido entre el Cantábrico oriental y el Valle del Ebro, durante el periodo internacional 1961-90. Este territorio está ocupado por las comunidades del País Vasco, Navarra, La Rioja y Aragón. Se estudian las temperaturas medias, las máximas, las mínimas, el coeficiente de variación y las heladas. También se incluye en el análisis anual, el estudio de la amplitud térmica, los quintiles y la tendencia futura.The present article aims at studying the temperatures in an área that goes from the cantábrico oriental and Valle del Ebro, for the international period of time going from 1961- 90. Four autonomous cornmunities. País Vasco, Navarra, La Rioja and Aragón, are included in this territory. The object of study will be the average, máximum and mínimum temperatures, as well as the coefficient of variation and freezes. It will also be included in the annual analysis. the study of thermal amplitude, quintiles, and future trend.

  14. Recognition of primary and diagenetic magnetizations to determine the magnetic polarity record and timing of deposition of the moat-fill rocks of the Oligocene Creede Caldera, Colorado

    Science.gov (United States)

    Reynolds, Richard L.; Rosenbaum, Joseph G.; Sweetkind, Donald S.; Lanphere, Marvin A.; Robert, Andrew P.; Verosub, Kenneth L.

    2000-01-01

    Sedimentary and volcaniclastic rocks of the Oligocene Creede Formation fill the moat of the Creede caldera, which formed at about 26.9 Ma during the eruption of the Snowshoe Mountain Tuff. Paleomagnetic and rock magnetic studies of two cores (418 and 703 m long) that penetrated the lower half of the Creede Formation, in addition to paleomagnetic and isotopic dating studies of stratigraphically bracketing volcanic units, provide information on the age and the time span of sedimentation of the caldera fill. Normal polarity magnetization are found in Snowshoe Mountain Tuff beneath the moat sediments; in detrital-magnetite-bearing graded tuffs near the bottom of the moat fill; in an ash-fall deposit about 200 m stratigraphically about the top of core 2; and in postcaldera lava flows of the Fisher Dacite that overlie the Creede Formation. Normal polarity also characterizes detrital-magnetite-bearing tuff and sandstone unites within the caldera moat rocks that did not undergo severe sulfidic alteration. The combination of initially low magnitude of remanent magnetization and the destructive effects of subsequent diagenetic sulfidization on detrital iron oxides results in a poor paleomagnetic record for the fine-grained sedimentary rocks of the Creede Formation. these fine-grained rocks have either normal or revered polarity magnetizations that are carried by magnetite and/or maghemite. Many more apparent reversals are found that can be accommodated by any geomagnetic polarity time scale over the interval spanned by the ages of the bracketing extrusive rocks. Moreover, opposite polarity magnetization are found in specimens separated by only a few centimeters, without intervening hiatuses, and by specimens in several tuff beds, each of which represents a single depositional event. These polarity changes cannot, therefore, be attributed to detrital remanent magnetization. Many polarity changes are apparently related to chemical remanent magnetizations carried by

  15. EL PATRIMONIO ARQUEOLÓGICO COMO RECURSO: POLÍTICAS ESTATALES DE GESTIÓN EN TUCUMÁN Y TAFÍ DEL VALLE / The archaeological heritage as a resource: State policies and management in Tucuman and Tafi del Valle

    Directory of Open Access Journals (Sweden)

    Barbara Manasse

    2010-12-01

    Full Text Available El territorio tucumano, en el centro del Noroeste argentino, es un área conocida por la riqueza de sus manifestaciones culturales materiales. Desde los comienzos de la constitución del Estado, Tucumán fue locus de distintas políticas y propuestas que las implicaban. Es factible rastrearlas en el accionar concreto sobre esos recursos culturales, así como también en los proyectos que se fueron planteando. Abordaremos un primer análisis de cómo desde el Estado se fue dibujando, definiendo, en fin, construyendo el “patrimonio arqueológico” en la provincia de Tucumán, en tanto conjunto de bienes culturales materiales que representaría parte del pasado local y que, por ende, merecería recibir un trato especial a los fines de garantizar su resguardo y conservación. Nuestro eje de estudio se centra en la materialidad indígena prehispánica del del Valle de Tafí en el Oeste tucumano indagando los diversos procesos y tomando en cuenta los diferentes actores que fueron configurando su patrimonialización en los contextos históricos, políticos y sociales de los últimos cien años. Consideramos que es un caso que puede ser paradigmático en pocos años más, tanto en lo que respecta al uso de los recursos culturales prehispánicos así como al destino de los mismos.Palabras clave: patrimonio; políticas estatales; arqueología; materialidades indígenas; Tafí del Valle.AbstractThe Tucuman region, located in the heart of Northwestern Argentina, is an area known for its wealth of cultural materials. From the earliest days of the nation, Tucuman has been a place where a wide range of policies and proposals have been advanced in relation to how these materials should be managed. It is therefore possible to review the concrete developments that have taken place along these lines, as well as the specifics of other projects that have been proposed.Here we undertake an initial analysis of how the State has engaged in the planning, definition

  16. Early-Middle Pleistocene benthic turnover and oxygen isotope stratigraphy from the Central Mediterranean (Valle di Manche, Crotone Basin, Italy): Data and trends

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    Michele Azzarone; Patrizia Ferretti; Veronica Rossi; Daniele Scarponi; Luca Capraro; Patrizia Macrì; John W. Huntley; Costanza Faranda

    2018-01-01

    Ostracod faunal turnover and oxygen isotope data (foraminifera) along the Valle di Manche (VdM) section are herein compiled. Specifically, the material reported in this work includes quantitative palaeoecological data and patterns of ostracod fauna framed within a high-resolution oxygen isotope stratigraphy (δ18O) from Uvigerina peregrina. In addition, the multivariate ostracod faunal stratigraphic trend (nMDS axis-1 sample score) is calibrated using bathymetric distributions of extant mollus...

  17. Morfología básica de 17 introducciones del género Ocimum en el departamento del Valle

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    Estrada Edgar Iván

    1987-09-01

    Full Text Available Los objetivos del trabajo fueron establecer un jardín de introducciones de albahaca y contribuir en la caracterización botánica de las cultivariedades introducidas al banco de germoplasma. La colección se realizó en el departamento del Valle en campos de cultivo, áreas de vegetación natural, huertos caseros y mercados locales. En 6 zonas se recolectaron 17 introducciones, pertenecientes a 5 especies del genero Ocimum tres cultivadas (O. basilicum L., O. americanum Jacq Host y 0. minimum L. y dos ornamentales (O. gratissimum Hook y O. micranthum Willd. Se determinó visualmente alta variación para características fenotípicas tales como arquitectura de plantas, presencia de pubescencia, tipo de inflorescencia, flores, hojas y frutos.The objetives of this work were the collection and stablishment of a garden of albahaca and a contribution to the botanical characteristic of the cultivars introduced in the germoplasm bank .The collection was gathered at cultivated fields, natural vegetation areas, house gardens and local markets. Seventeen (17 species were collected, all belonging to the generous Ocimum from six different zones of Valle del Cauca. Three species are cultivated (O. basilium L., O. americanum Jack Host y O. minimum L. and two are considered ornamentals (O. gratissimum Hook y O. micranthum Willd. Phenotipicaly, high variety was observed in the plant architecture, in its pubescence presence, in the type of inflorescence and in flowers, leaves and fruits.

  18. Application of the business model Canvas in Microenterprises from Partners of the Savings and Credit Cooperative Luz del Valle

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    Francisco Javier Monroy Espinosa

    2017-12-01

    Full Text Available The "Luz del Valle" Savings and Credit Cooperative is a financial institution with five thousand microentrepreneurial partners who have business units. These business units, generally informal, do not have a defined organizational structure or adequate management tools, which influences in the presence of economic problems such as arrears and non-payment of contracted obligations, mainly as a result of a low level of sales. Due to this situation, it is important for cooperatives to support their partners in finding solutions. This is part of the cooperative principles and values of mutual aid, social responsibility and education, training and information for its members, team leaders, managers and employees; these universal principles established by the International Cooperative Alliance (ICA are considered by the savings and credit cooperative "Luz del Valle" as strategies to accompany its partners in the development and growth of their business units. The cooperative organizes a Christmas Fair annually, where 60 microentrepreneurs participate. This event was the opportunity to develop, together with the Metropolitan University of Ecuador, a project that, in its first phase, trained in the formulation of strategies based on the application of the Business Model Canvas; the teaching of this tool, which allows creating, capturing and providing value for clients, was supported by the university community and the program of linkage with society that develops the aforementioned institution; the evaluation of the impact and the economic results are contemplated in a second phase.

  19. Construcción rural como representación. Infraestructura agrícola menor en el valle central de Chile

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    Juan Paulo Alarcón

    2017-11-01

    Full Text Available Los gallineros, secadores de maíz, bodegas, caballerizas, etc. del valle central de Chile son construcciones menores que funcionan como infraestructuras que complementan la producción agrícola básica y de pequeña escala que allí se desarrolla con lo cual su resolución, que roza lo arcaico, está desprovista de un germen disciplinar. Estas construcciones, si bien pueden ser la culminación material de una idea, más bien se plantean como la representación en sí misma de un proyecto, en un estado pendiente de resolución, que se ha ido forjando generación tras generación. Esparcidas en el territorio, representan tanto el carácter agrícola de la zona, como la inteligencia desplegada a lo largo del tiempo, determinada por las condiciones geográficas, culturales y sociales, en un contexto de escasez. Si bien tiene antecedentes en las edificaciones residenciales primitivas, se origina como tipo en la reforma agraria, cuando se reparten las tierras en superficies pequeñas que promueven el desarrollo de la agricultura menor. Las construcciones rurales en el valle central de Chile son en sí mismo la representación de su proyecto y, como manifestaciones, representan una actividad comunal, un territorio, un paisaje, un modelo económico, un ideal político.

  20. Indagini Stratigrafiche e Sistemi Informativi Architettonici: il GIS della chiesa di S. Maria in Valle Porclaneta

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    Trizio, Ilaria

    2009-12-01

    Full Text Available The church of Santa Maria in Valle Porclaneta and its accessories are what remains of an ancient Benedictine monastery, built in the heart of Abruzzo region (Magliano dei Marsi, L’Aquila at the end of the XII century. Even if literature, starting from the end of XIX century, has been often interested in this architectural manufactured, the process of historical-critical knowledge of the complex revealed itself difficult due to the absence of archaeological data, the shortage of the documents and, above all, the numerous interventions of restoration that, followed during all last century, have deeply modified the original compages of it. Due to the difficulties met, the overlap between the few documental data and the data derived from the direct investigation of the structures, performed with the aid of an Architectural Informative System, made possible to hypothesize a chronological reconstruction of the principal phases of life of the monastic complex.[it] La chiesa di Santa Maria in Valle Porclaneta e i suoi ambienti accessori sono quanto resta di un antico monastero benedettino, edificato nel cuore del territorio abruzzese (Magliano dei Marsi, L’Aquila sul finire del XII secolo. Sebbene la letteratura, a partire dalla fine dell’Ottocento, si sia spesso occupata di questo manufatto, il processo di conoscenza storico-critica del complesso si è rivelato difficoltoso a causa dell’assenza di dati archeologici, della scarsità di fonti documentarie pervenute, e, soprattutto a causa del susseguirsi di numerosi interventi di restauro che, succedutisi senza soluzione di continuità per tutto il secolo scorso, ne hanno letteralmente stravolto la compagine originale. A fronte delle difficoltà incontrate, la sovrapposizione tra i pochi dati documentali e i dati derivati dall’indagine diretta delle strutture, eseguita con l’ausilio di un Sistema Informativo Architettonico ha consentito di ipotizzare una ricostruzione cronologica delle