WorldWideScience

Sample records for eruptive prominence evidence

  1. Multispacecraft observations of a prominence eruption

    Directory of Open Access Journals (Sweden)

    A. Bemporad

    2009-10-01

    Full Text Available On 9 May 2007 a prominence eruption occurred at the West limb. Remarkably, the event was observed by the STEREO/EUVI telescopes and by the HINODE/EIS and SOHO/UVCS spectrometers. We present results from all these instruments. High-cadence (~37 s data from STEREO/EUVI A and B in the He II λ304 line were used to study the 3-D shape and expansion of the prominence. The high spatial resolution EUVI images (~1.5"/pixel have been used to infer via triangulation the 3-D shape and orientation of the prominence 12 min after the eruption onset. At this time the prominence has mainly the shape of a "hook" highly inclined southward, has an average thickness of 0.068 R⊙, a length of 0.43 R⊙ and lies, in first approximation, on a plane. Hence, the prominence is mainly a 2-D structure and there is no evidence for a twisted flux rope configuration. HINODE/EIS was scanning with the 2" slit the region where the filament erupted. The EIS spectra show during the eruption remarkable non-thermal broadening (up to ~100 km s−1 in the region crossed by the filament in spectral lines emitted at different temperatures, possibly with differences among lines from higher Fe ionization stages. The CME was also observed by the SOHO/UVCS instrument: the spectrograph slit was centered at 1.7 R⊙, at a latitude of 5° SW and recorded a sudden increase in the O VI λλ1032–1037 and Si XII λ520 spectral line intensities, representative of the CME front transit.

  2. Study of a Large Helical Eruptive Prominence Associated with ...

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... Here we present a preliminary analysis of a helical eruptive prominence at the east limb of the Sun on 21 April 2001. Unusually this eruption is associated with a double CME. We have tried to study the morphology of the event, energy budget of the prominence and associated CMEs. Our analysis shows ...

  3. Study of a Large Helical Eruptive Prominence Associated with ...

    Indian Academy of Sciences (India)

    2001-04-21

    Apr 21, 2001 ... Abstract. Here we present a preliminary analysis of a helical eruptive prominence at the east limb of the Sun on 21 April 2001. Unusually this eruption is associated with a double CME. We have tried to study the morphology of the event, energy budget of the prominence and associated. CMEs. Our analysis ...

  4. Rolling Motions During Solar Prominence Eruptions in Asymmetric Magnetic Environments

    Science.gov (United States)

    McKillop, Sean; Miralles, Mari Paz; Murphy, Nicholas Arnold; McCauley, Patrick

    2014-06-01

    Panasenco et al. [1] report observations of several CMEs that display a rolling motion about the axis of the erupting prominence. Murphy et al. [2] present simulations of line-tied asymmetric magnetic reconnection that make a falsifiable prediction regarding the handedness of rolling motions of flux ropes during solar eruptions. We will present initial results of our work to investigate this prediction. To determine the strength and any asymmetric properties of the magnetic field in the regions of interest in the photosphere, we use magnetograms from HMI. We use AIA observations to determine if there is any rolling motion and, if so, what handedness the rolling motions have. We then compare the photospheric magnetic information with the handedness information to determine if there is any relationship between the two. Finally, we will discuss prospects for diagnosing rolling motions of erupting prominence using off-limb IRIS observations.[1] O. Panasenco, S. Martin, A. D. Joshi, & N. Srivastava, J. Atmos. Sol.-Terr. Phys., 73, 1129 (2011)[2] N. A. Murphy, M. P. Miralles, C. L. Pope, J. C. Raymond, H. D. Winter, K. K. Reeves, D. B. Seaton, A. A. van Ballegooijen, & J. Lin, ApJ, 751, 56 (2012)

  5. Complex Eruptive Dynamics Leading to a Prominence Eruption and a Partial-Halo Coronal Mass Ejection

    Science.gov (United States)

    Dechev, M.; Duchlev, P.; Koleva, K.

    2018-02-01

    We present very rarely reported case of an eruptive prominence (EP) composed by both hot, bright flux rope (BFR) and cool massive flux ropes (MFR) and associated partial-halo coronal mass ejection (CME). Using SDO and STEREO A and B multi-wavelength observations, we examined in detail the eruption of EP flux ropes (FRs) and their associated activities in a complex magnetic configuration located beneath a multiarcade helmet streamer. We establish the sequence of activities appearance involved in casually linked chain of events on 2014 March 14: short-lived active region, surge eruption, EP BFR rising, EP BFR and MFR merging and interacting, EP common FR fast rise, flare, EP FR bifurcation, partial-halo CME with bi-component bright core, impulsive flare, post-flare loop arcade. A surge-like event in the northern EP footpoints is determined as the possible trigger of the bright FR appearance beneath the cool, massive FR. Plasma draining in this footpoints is identified as the precursor for the EP eruption. We find that the EP FRs merging at the fast-rise onset and their splitting in the phase of strong acceleration are the main triggers for the flaring activity. Studying the eruptions of EP hot and cool FRs with their associated CME, we find that they are co-spatial with the CME bright core, i.e. the hot and cool EP FRs produced bi-component CME bright core.

  6. Heating of an Erupting Prominence Associated with a Solar Coronal Mass Ejection on 2012 January 27

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jin-Yi; Moon, Yong-Jae; Kim, Kap-Sung [Department of Astronomy and Space Science, Kyung Hee University, Yongin-si, Gyeonggi-do, 17104 (Korea, Republic of); Raymond, John C.; Reeves, Katharine K. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)

    2017-07-20

    We investigate the heating of an erupting prominence and loops associated with a coronal mass ejection and X-class flare. The prominence is seen as absorption in EUV at the beginning of its eruption. Later, the prominence changes to emission, which indicates heating of the erupting plasma. We find the densities of the erupting prominence using the absorption properties of hydrogen and helium in different passbands. We estimate the temperatures and densities of the erupting prominence and loops seen as emission features using the differential emission measure method, which uses both EUV and X-ray observations from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory and the X-ray Telescope on board Hinode . We consider synthetic spectra using both photospheric and coronal abundances in these calculations. We verify the methods for the estimation of temperatures and densities for the erupting plasmas. Then, we estimate the thermal, kinetic, radiative loss, thermal conduction, and heating energies of the erupting prominence and loops. We find that the heating of the erupting prominence and loop occurs strongly at early times in the eruption. This event shows a writhing motion of the erupting prominence, which may indicate a hot flux rope heated by thermal energy release during magnetic reconnection.

  7. Study of a Large Helical Eruptive Prominence Associated with ...

    Indian Academy of Sciences (India)

    2001-04-21

    )/(dt2) = 0, the balance current is derived. (Van Tend & Kuperus 1978) for equilibrium height, h = 1.02 × 1010 cm. The loop length of the prominence at this height is measured to be, l = 2.9×1010 cm and mass, m = 0.5 × 1015 g.

  8. MHD simulations of the eruption of prominence hosting coronal flux ropes

    Science.gov (United States)

    Fan, Yuhong

    2017-08-01

    We present MHD simulations of the eruption of a prominence hosting coronal flux rope under a coronal streamer, with the thermodynamic treatment including a simple empirical coronal heating, optically thin radiative cooling and the field aligned thermal conduction. We first initialize a quasi-steady solar wind solution with a coronal helmet streamer, using an initial normal flux distribution of a simple bipolar arcade field on the lower boundary. Then into this coronal streamer with an ambient solar wind we impose at the lower boundary the slow emergence of a twisted magnetic torus. As a result a quasi-equilibrium flux rope is built up under the streamer magnetic field. With varying sizes of the streamer and the different length and total twist of the emerged flux rope, we found different scenarios for the evolution from quasi-equilibrium to loss of confinement and eruption. In the case with a broad streamer with slow decline of the overlying field, the flux rope remains well confined until there is sufficient twist such that it first develops the kink instability and evolves through a sequence of kinked, confined states with its apex rises slowly. It eventually develops a “hernia-like” eruption when the kinked apex reaches a certain height and can no-longer be confined. We find that for the long, significantly twisted flux ropes, prominence condensations form in the dips of the twisted field lines due to run-away radiative cooling. Once formed, the prominence carrying field becomes significantly non force-free due to the prominence weight despite being low plasma β. As the flux rope erupts, we also obtain the eruption of the prominence, which shows substantial draining along the legs of the erupting flux rope during the eruption. The prominence may not show a kinked morphology even the flux rope becomes kinked. On the other hand in the case with a narrower streamer, the flux rope with less than 1 wind of twist can erupt via the onset of the torus instability.

  9. Quiescent and Eruptive Prominences at Solar Minimum: A Statistical Study via an Automated Tracking System

    Science.gov (United States)

    Loboda, I. P.; Bogachev, S. A.

    2015-07-01

    We employ an automated detection algorithm to perform a global study of solar prominence characteristics. We process four months of TESIS observations in the He II 304Å line taken close to the solar minimum of 2008-2009 and mainly focus on quiescent and quiescent-eruptive prominences. We detect a total of 389 individual features ranging from 25×25 to 150×500 Mm2 in size and obtain distributions of many of their spatial characteristics, such as latitudinal position, height, size, and shape. To study their dynamics, we classify prominences as either stable or eruptive and calculate their average centroid velocities, which are found to rarely exceed 3 km/s. In addition, we give rough estimates of mass and gravitational energy for every detected prominence and use these values to estimate the total mass and gravitational energy of all simultaneously existing prominences (1012 - 1014 kg and 1029 - 1031 erg). Finally, we investigate the form of the gravitational energy spectrum of prominences and derive it to be a power-law of index -1.1 ± 0.2.

  10. The Apparent Critical Decay Index at the Onset of Solar Prominence Eruptions

    Science.gov (United States)

    Zuccarello, F. P.; Aulanier, G.; Gilchrist, S. A.

    2016-04-01

    A magnetic flux rope (MFR) embedded in a line-tied external magnetic field that decreases with height as {z}-n is unstable to perturbations if the decay index of the field n is larger than a critical value. The onset of this instability, called torus instability, is one of the main mechanisms that can initiate coronal mass ejections. Since flux ropes often possess magnetic dips that can support prominence plasma, this is also a valuable mechanism to trigger prominence eruptions. Magnetohydrodynamic (MHD) simulations of the formation and/or emergence of MFRs suggest a critical value for the onset of the instability in the range [1.4-2]. However, detailed observations of prominences suggest a value in the range [0.9-1.1]. In this Letter, by using a set of MHD simulations, we show why the large discrepancy between models and observations is only apparent. Our simulations indeed show that the critical decay index at the onset of the eruption is n=1.4+/- 0.1 when computed at the apex of the flux rope axis, while it is n=1.1+/- 0.1 when it is computed at the altitude of the topmost part of the distribution of magnetic dips. The discrepancy only arises because weakly twisted curved flux ropes do not have dips up to the altitude of their axis.

  11. PRE-FLARE CORONAL JET AND EVOLUTIONARY PHASES OF A SOLAR ERUPTIVE PROMINENCE ASSOCIATED WITH THE M1.8 FLARE: SDO AND RHESSI OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Bhuwan; Kushwaha, Upendra [Udaipur Solar Observatory, Physical Research Laboratory, Udaipur 313001 (India); Veronig, Astrid M. [Kanzelhöhe Observatory/Institute of Physics, University of Graz, Universitätsplatz 5, A-8010 Graz (Austria); Cho, K.-S., E-mail: bhuwan@prl.res.in [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of)

    2016-12-01

    We investigate the triggering, activation, and ejection of a solar eruptive prominence that occurred in a multi-polar flux system of active region NOAA 11548 on 2012 August 18 by analyzing data from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory , the Reuven Ramaty High Energy Solar Spectroscopic Imager , and the Extreme Ultraviolet Imager/Sun Earth Connection Coronal and Heliospheric Investigation on board the Solar Terrestrial Relation Observatory . Prior to the prominence activation, we observed striking coronal activities in the form of a blowout jet, which is associated with the rapid eruption of a cool flux rope. Furthermore, the jet-associated flux rope eruption underwent splitting and rotation during its outward expansion. These coronal activities are followed by the prominence activation during which it slowly rises with a speed of ∼12 km s{sup −1} while the region below the prominence emits gradually varying EUV and thermal X-ray emissions. From these observations, we propose that the prominence eruption is a complex, multi-step phenomenon in which a combination of internal (tether-cutting reconnection) and external (i.e., pre-eruption coronal activities) processes are involved. The prominence underwent catastrophic loss of equilibrium with the onset of the impulsive phase of an M1.8 flare, suggesting large-scale energy release by coronal magnetic reconnection. We obtained signatures of particle acceleration in the form of power-law spectra with hard electron spectral index ( δ  ∼ 3) and strong HXR footpoint sources. During the impulsive phase, a hot EUV plasmoid was observed below the apex of the erupting prominence that ejected in the direction of the prominence with a speed of ∼177 km s{sup −1}. The temporal, spatial, and kinematic correlations between the erupting prominence and the plasmoid imply that the magnetic reconnection supported the fast ejection of prominence in the lower corona.

  12. Evidence for Mixed Helicity in Erupting Filaments

    Science.gov (United States)

    Muglach, K.; Wang, Y.-M.; Kliem, B.

    2009-09-01

    Erupting filaments are sometimes observed to undergo a rotation about the vertical direction as they rise. This rotation of the filament axis is generally interpreted as a conversion of twist into writhe in a kink-unstable magnetic flux rope. Consistent with this interpretation, the rotation is usually found to be clockwise (as viewed from above) if the post-eruption arcade has right-handed helicity, but counterclockwise if it has left-handed helicity. Here, we describe two non-active-region filament events recorded with the Extreme-Ultraviolet Imaging Telescope on the Solar and Heliospheric Observatory in which the sense of rotation appears to be opposite to that expected from the helicity of the post-event arcade. Based on these observations, we suggest that the rotation of the filament axis is, in general, determined by the net helicity of the erupting system, and that the axially aligned core of the filament can have the opposite helicity sign to the surrounding field. In most cases, the surrounding field provides the main contribution to the net helicity. In the events reported here, however, the helicity associated with the filament "barbs" is opposite in sign to and dominates that of the overlying arcade.

  13. Solar prominences

    CERN Document Server

    Engvold, Oddbjørn

    2015-01-01

    This volume presents the latest research results on solar prominences, including new developments on e.g. chirality, fine structure, magnetism, diagnostic tools and relevant solar plasma physics. In 1875 solar prominences, as seen out of the solar limb, were described by P.A. Secchi in his book Le Soleil as "gigantic pink or peach-flower coloured flames". The development of spectroscopy, coronagraphy and polarimetry brought tremendous observational advances in the twentieth century. The authors present and discuss exciting new challenges (resulting from observations made by space and ground-based telescopes in the 1990s and the first decade of the 21st century) concerning the diagnostics of prominences, their formation, their life time and their eruption along with their impact in the heliosphere (including the Earth). The book starts with a general introduction of the prominence “object” with some historical background on observations and instrumentation. In the next chapter, the various forms of promine...

  14. Fuego Volcano eruption (Guatemala, 1974): evidence of a tertiary fragmentation?

    International Nuclear Information System (INIS)

    Brenes-Andre, Jose

    2014-01-01

    Values for mode and dispersion calculated from SFT were analyzed using the SFT (Sequential Fragmentation/Transport) model to Fuego Volcano eruption (Guatemala, 1974). Analysis results have showed that the ideas initially proposed for Irazu, can be applied to Fuego Volcano. Experimental evidence was found corroborating the existence of tertiary fragmentations. (author) [es

  15. Direct Evidence of an Eruptive, Filament-hosting Magnetic Flux Rope Leading to a Fast Solar Coronal Mass Ejection

    Science.gov (United States)

    Chen, Bin; Bastian, T. S.; Gary, D. E.

    2014-10-01

    Magnetic flux ropes (MFRs) are believed to be at the heart of solar coronal mass ejections (CMEs). A well-known example is the prominence cavity in the low corona that sometimes makes up a three-part white-light (WL) CME upon its eruption. Such a system, which is usually observed in quiet-Sun regions, has long been suggested to be the manifestation of an MFR with relatively cool filament material collecting near its bottom. However, observational evidence of eruptive, filament-hosting MFR systems has been elusive for those originating in active regions. By utilizing multi-passband extreme-ultraviolet (EUV) observations from Solar Dynamics Observatory/Atmospheric Imaging Assembly, we present direct evidence of an eruptive MFR in the low corona that exhibits a hot envelope and a cooler core; the latter is likely the upper part of a filament that undergoes a partial eruption, which is later observed in the upper corona as the coiled kernel of a fast, WL CME. This MFR-like structure exists more than 1 hr prior to its eruption, and displays successive stages of dynamical evolution, in which both ideal and non-ideal physical processes may be involved. The timing of the MFR kinematics is found to be well correlated with the energy release of the associated long-duration C1.9 flare. We suggest that the long-duration flare is the result of prolonged energy release associated with the vertical current sheet induced by the erupting MFR.

  16. Direct evidence of an eruptive, filament-hosting magnetic flux rope leading to a fast solar coronal mass ejection

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Bin; Gary, D. E. [Center for Solar-Terrestrial Research, New Jersey Institute of Technology, Newark, NJ 07102 (United States); Bastian, T. S., E-mail: bin.chen@cfa.harvard.edu [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States)

    2014-10-20

    Magnetic flux ropes (MFRs) are believed to be at the heart of solar coronal mass ejections (CMEs). A well-known example is the prominence cavity in the low corona that sometimes makes up a three-part white-light (WL) CME upon its eruption. Such a system, which is usually observed in quiet-Sun regions, has long been suggested to be the manifestation of an MFR with relatively cool filament material collecting near its bottom. However, observational evidence of eruptive, filament-hosting MFR systems has been elusive for those originating in active regions. By utilizing multi-passband extreme-ultraviolet (EUV) observations from Solar Dynamics Observatory/Atmospheric Imaging Assembly, we present direct evidence of an eruptive MFR in the low corona that exhibits a hot envelope and a cooler core; the latter is likely the upper part of a filament that undergoes a partial eruption, which is later observed in the upper corona as the coiled kernel of a fast, WL CME. This MFR-like structure exists more than 1 hr prior to its eruption, and displays successive stages of dynamical evolution, in which both ideal and non-ideal physical processes may be involved. The timing of the MFR kinematics is found to be well correlated with the energy release of the associated long-duration C1.9 flare. We suggest that the long-duration flare is the result of prolonged energy release associated with the vertical current sheet induced by the erupting MFR.

  17. Direct evidence of an eruptive, filament-hosting magnetic flux rope leading to a fast solar coronal mass ejection

    International Nuclear Information System (INIS)

    Chen, Bin; Gary, D. E.; Bastian, T. S.

    2014-01-01

    Magnetic flux ropes (MFRs) are believed to be at the heart of solar coronal mass ejections (CMEs). A well-known example is the prominence cavity in the low corona that sometimes makes up a three-part white-light (WL) CME upon its eruption. Such a system, which is usually observed in quiet-Sun regions, has long been suggested to be the manifestation of an MFR with relatively cool filament material collecting near its bottom. However, observational evidence of eruptive, filament-hosting MFR systems has been elusive for those originating in active regions. By utilizing multi-passband extreme-ultraviolet (EUV) observations from Solar Dynamics Observatory/Atmospheric Imaging Assembly, we present direct evidence of an eruptive MFR in the low corona that exhibits a hot envelope and a cooler core; the latter is likely the upper part of a filament that undergoes a partial eruption, which is later observed in the upper corona as the coiled kernel of a fast, WL CME. This MFR-like structure exists more than 1 hr prior to its eruption, and displays successive stages of dynamical evolution, in which both ideal and non-ideal physical processes may be involved. The timing of the MFR kinematics is found to be well correlated with the energy release of the associated long-duration C1.9 flare. We suggest that the long-duration flare is the result of prolonged energy release associated with the vertical current sheet induced by the erupting MFR.

  18. Signs of helicity in solar prominences and related features

    Science.gov (United States)

    Martin, S.

    This review illustrates several ways to identify the chirality (handedness) of solar prominences (filaments) from their structure and the structure of their surrounding magnetic fields in the chromosphere and corona. For prominences, these structural elements include the axial magnetic field direction, orientation of barbs, and direction of the prominence fine structure. The surrounding structures include the pattern of fibrils beneath the prominences and the pattern of coronal loops above the prominences. These ways of identifying chirality are then interpreted in terms of the formal definitions of helicity to yield a consistent set of one-to-one helicity relationships for all features. The helicity of some prominences can also be independently determined during their eruption by their fine structure, apparent crossings in the line-of-sight of different parts of the same prominence, and by large- scale twist of the prominence structure. Unlike observations of prominences (filaments) observed prior to eruption, in some cases evidence of both signs of helicity are found within the same erupting prominence. This indicates the continued application of forces on the prominences during the eruption process or the possible introduction of force(s) not present during earlier stages of their evolution.

  19. A subaqueous eruption model for shallow-water, small volume eruptions: Evidence from two Precambrian examples

    Science.gov (United States)

    Mueller, Wulf U.

    Ancient, shallow-water, pyroclastic deposits are identified in the Paleoproterozoic Ketilidian Mobile belt, southeast Greenland at Kangerluluk and in the Neoproterozoic Gariep belt of Namibia in the Schakalsberg Mountains. The 1-30 m-thick tuff and lapilli tuff deposits are interpreted as eruption-fed density current deposits emanating from tephra jets that collapsed under subaqueous conditions due to water ingress. The presence of 1-10 mm diameter armoured lapilli, with a central vesicular lapillus or shard, suggests the existence of high velocity, gas, water vapour, and particle-rich tephra jets. A transition from a gas-steam supported tephra jet to a cold water-laden density current without an intermediate stage of storage and remobilization is inferred. Interpretation of a 5-15 m-thick lapilli tuff breccia further supports explosive subaqueous mechanisms. Pyroclasts in the lapilli tuff breccia are interpreted as bombs emplaced ballistically. Multiple bomb sags produced by the impact of rounded juvenile crystal-rich pyroclasts required a water-exclusion zone formed either by a continuous magma uprush or multiple jet activity occurring concurrently, rather than as isolated tephra jets. Intercalated density current deposits indicate uprush events of limited duration and their recurrence with rapid collapse after each pulse. A new subaqueous Surtseyan-type eruption model is proposed based on observations from these two Precambrian study areas.

  20. The Prominence and Behavior of Multiplets Prior to and During Volcanic Eruptions at Bezymianny Volcano, Russia and Mount St. Helens, Washington

    Science.gov (United States)

    Thelen, W. A.; Malone, S. D.; West, M. E.

    2009-12-01

    Earthquake multiplets are commonly reported on volcanoes worldwide; however, their utility as a tool in forecasting eruptions and monitoring volcanic activity has been poorly explored. We have developed a method that allows us to characterize multiplets from continuous data on multiple stations, therefore considering all events occurring over long time periods. By tracking temporal changes in multiplet behavior, we hope to provide an additional tool for eruption forecasting. In this study we use the multiplet catalog to track changes in multiplet behavior across several eruptive phenomenon at Bezymianny Volcano, Russia in 2007 and at Mount St. Helens, Washington during the beginning of its dome-building eruption in 2004. The October 2007 eruption at Bezymianny consisted of two large explosions, pyroclastic flows and an andesitic lava flow. Several days prior to the eruption at Bezymianny in October 2007, multiplet lifespans, the number of concurrent multiplets and the multiplet proportion of total seismicity (MPTS) all decreased. Additionally, the average amplitude of events and standard deviation about the average increased prior to the large October 2007 eruption. These trends suggest building instability in the multiplet source area prior to the large eruption. All of the analyzed parameters gradually returned to background values several days after the eruption. Another small explosion in September 2007 and a minor dome collapse in November 2007 did not obviously affect any of the multiplet parameters studied here. The 2004 eruption at Mount St. Helens began with several small explosions. Approximately 2 weeks after the first explosion, dome building began, dominantly as spine extrusion. Throughout the first two months of the 2004 eruption at Mount St. Helens, the MPTS was noticeably higher than at Bezymianny Volcano, perhaps reflecting the presence of a viscous plug in the shallow conduit at Mount St. Helens. Similar to Bezymianny, the average amplitude of

  1. Re-interpreting Prominences Classified as Tornadoes

    Science.gov (United States)

    Martin, Sara F.; Venkataramanasastry, Aparna

    2015-04-01

    Some papers in the recent literature identify tornado prominences with barbs of quiescent prominences while papers in the much older historic literature include a second category of tornado prominence that does not correspond to a barb of a quiescent prominence. The latter are described as prominence mass rotating around a nearly vertical axis prior to its eruption and the rotation was verified by spectral measurements. From H alpha Doppler-shifted mass motions recorded at Helio Research or the Dutch Open Telescope, we illustrate how the apparent tornado-like motions, identified with barbs, are illusions in our mind’s eye resulting from poorly resolved counterstreaming threads of mass in the barbs of quiescent prominences. In contrast, we confirm the second category of rotational motion in prominences shortly before and during eruption. In addition, we identify this second category as part of the late phase of a phenomenon called the roll effect in erupting prominences. In these cases, the eruption begins with the sideways rolling of the top of a prominence. As the eruption proceeds the rolling motion propagates down one leg or both legs of the prominence depending on whether the eruption is asymmetric or symmetric respectively. As an asymmetric eruption continues, the longer lasting leg becomes nearly vertical and its rotational motion also continues. If only this phase of the eruption was observed, as in some historic cases, it was called a tornado prominence. However, when we now observe entire eruptions in time-lapse sequences, the similarity to terrestrial tornadoes is lost. We conclude that neither prominence barbs, that give the illusion of rotation, nor the cases of true rotational motion, in the legs of erupting prominences, are usefully described as tornado prominences when the complete prominence structure or complete erupting event is observed.

  2. Historical evidence for a connection between volcanic eruptions and climate change

    Science.gov (United States)

    Rampino, Michael R.

    1991-01-01

    The times of historical volcanic aerosol clouds were compared with changes in atmospheric temperatures on regional, hemispheric, and global scales. These involve either a direct comparison of individual significant eruption years with temperature records, or a comparison of eruption years with composited temperature records for several years before and after chosen sets of eruptions. Some studies have challenged the connection between individual eruptions and climate change. Mass and Portman (1989) recently suggested that the volcanic signal was present, but smaller than previously thought. In a study designed to test the idea that eruptions could cause small changes in climate, Hansen and other (1978) chose one of the best monitored eruptions at the time, the 1963 eruption of Agung volcano on the island of Bali. Using a simple radiation-balance model, in which an aerosol cloud in the tropics was simulated, this basic pattern of temperature change in the tropics and subtropics was reproduced. There may be natural limits to the atmospheric effects of any volcanic eruption. Self-limiting physical and chemical effects in eruption clouds were proposed. Model results suggest that aerosol microphysical processes of condensation and coagulation produce larger aerosols as the SO2 injection rate is increased. The key to discovering the greatest effects of volcanoes on short-term climate may be to concentrate on regional temperatures where the effects of volcanic aerosol clouds can be amplified by perturbed atmospheric circulation patterns, especially changes in mid-latitudes where meridional circulation patterns may develop. Such climatic perturbations can be detected in proxy evidence such as decreases in tree-ring widths and frost damage rings in climatically sensitive parts of the world, changes in treelines, weather anomalies such as unusually cold summers, severity of sea-ice in polar and subpolar regions, and poor grain yields and crop failures.

  3. No evidence for shallow shear motion on the Mat Fault, a prominent ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 124; Issue 5. No evidence for shallow shear ... The motion between India and Sunda plates is accommodated along the Churachandpur Mao Fault (CMF) in the Indo-Burmese Wedge (IBW) and Sagaing Fault in the Myanmar region. Within the IBW, the Mat Fault is ...

  4. No evidence for an afrotherian-like delayed dental eruption in South American notoungulates

    Science.gov (United States)

    Billet, Guillaume; Martin, Thomas

    2011-06-01

    The fossil South American ungulates are of great interest relative to the new phylogenetic framework elaborated for living placental mammals. In particular, studies on these endemic taxa can allow for testing congruence between southern placental phylogeny and plate tectonics, beyond what has already been suggested in the Atlantogenata hypothesis based on extant afrotherians and xenarthrans. The presence of delayed dental eruption relative to skull growth is one feature characterizing the extant afrotherians and possibly the xenarthrans. Late dental eruption has been mentioned previously in South American notoungulates, thus suggesting possible resemblance with afrotherians and perhaps xenarthrans. We provide here a detailed study of the dental eruption pattern relative to the skull growth in the notoungulates. In contrast to previous statements, our results demonstrate that there is currently no evidence for an afrotherian-like delayed dental eruption in this group. For now, the inferred absence of a delayed dental eruption in notoungulates does not support atlantogenatan/afrotherian affinities for the Notoungulata, but other atlantogenatan/afrotherian characteristics remain to be explored in more detail in this group and other South American ungulates.

  5. Late Holocene history of Chaitén Volcano: new evidence for a 17th century eruption

    Science.gov (United States)

    Lara, Luis E.; Moreno, Rodrigo; Amigo, Álvaro; Hoblitt, Richard P.; Pierson, Thomas C.

    2013-01-01

    Prior to May 2008, it was thought that the last eruption of Chaitén Volcano occurred more than 5,000 years ago, a rather long quiescent period for a volcano in such an active arc segment. However, increasingly more Holocene eruptions are being identified. This article presents both geological and historical evidence for late Holocene eruptive activity in the 17th century (AD 1625-1658), which included an explosive rhyolitic eruption that produced pumice ash fallout east of the volcano and caused channel aggradation in the Chaitén River. The extents of tephra fall and channel aggradation were similar to those of May 2008. Fine ash, pumice and obsidian fragments in the pre-2008 deposits are unequivocally derived from Chaitén Volcano. This finding has important implications for hazards assessment in the area and suggests the eruptive frequency and magnitude should be more thoroughly studied.

  6. Miniature Filament Eruptions and their Reconnections in X-Ray Jets: Evidence for a New Paradigm

    Science.gov (United States)

    Sterling, Alphonse C.; Moore, Ronald L.; Falconer, David A.

    2014-01-01

    We investigate the onset of approximately10 random X-ray jets observed by Hinode/XRT. Each jet was near the limb in a polar coronal hole, and showed a ``bright point'' in an edge of the base of the jet, as is typical for previously-observed X-ray jets. We examined SDO/AIA EUV images of each of the jets over multiple AIA channels, including 304 Ang, which detects chromospheric emissions, and 171, 193, and 211 Ang, which detect cooler-coronal emissions. We find the jets to result from eruptions of miniature (size less than approximately 10 arcsec) filaments from the bases of the jets. Much of the erupting-filament material forms a chromospheric-temperature jet. In the cool-coronal channels, often the filament appears in absorption and the jet in emission. The jet bright point forms at the location from which the miniature filament is ejected, analogous to the formation of a standard solar flare in the wake of the eruption of a typical larger-scale chromospheric filament. Thus these X-ray jets and their bright points are made by miniature filament eruptions. They are evidently produced the same way as an on-disk coronal jet we observed in Adams et al. (2014); that on-disk jet had no obvious emerging magnetic field in its base. We conclude that, for many jets, the standard idea of X-ray jets forming from reconnection between emerging flux and preexisting coronal field is incorrect. ACS and RLM were supported by funding from NASA/LWS, Hinode, and ISSI.

  7. Basaltic scoria fallout deposits from Ambrym volcano (Vanuatu archipelago): Textural and geochemical evidence of plinian eruptive styles

    Science.gov (United States)

    Balcone-Boissard, H.; Boudon, G.; Poulain, P.

    2017-12-01

    Plinian eruptions are among the most threatening volcanic hazard responsible of gas and solid particles release into atmosphere leading to potential damages at various spatial and time scales. Such explosive activity generally involves differentiated magmas, silica-rich enough to behave as viscous media and volatile-rich enough to generate significant overpressure in ascending magma. In some rare cases, Plinian eruptions can occur with more basic magmas as basalts. Few eruptions are now recognized on Earth, on Etna (122 BC), Masaya (Fontana) or Tarawera (1886). On Ambrym volcano (Vanuatu), the caldera formation was the result of several large eruptions including some Plinian events dated around 2000 yr. BP. By applying joint textural and geochemical investigations of a representative stratigraphic section of one of these eruptions we present new arguments to discuss the origin of such explosivity for basic magma. To achieve this goal we establish a degassing budget (H2O, CO2, SO2, F, Cl) through the petrological investigation by comparing melt inclusion and residual glass. We compare these results to those of quantitative textural description of pumice clasts through SEM images treated using Image J software, thus linking textural and geochemical arguments. We thus highlight that a low volatile content is not responsible of the overpressure leading to explosivity. Textural characteristics evidence vesicle organisation and low microlite content close that described for Plinian eruption involving differentiated melt. Degassing processes occur following a closed-system degassing evolution well correlated with textural parameters. By comparison to deposits of other basaltic Plinian eruptions, we show that for 122 BC eruption of Mt Etna, textural signature is diverse although we also evidence closed-system degassing processes. This study also permits to confirm that Ambrym is a valuable contributor to halogen release into the atmosphere at a time of reflexion on

  8. Degassing, crystallization and eruption dynamics at Stromboli: trace element and lithium isotopic evidence from 2003 ashes

    Science.gov (United States)

    Schiavi, Federica; Kobayashi, Katsura; Moriguti, Takuya; Nakamura, Eizo; Pompilio, Massimo; Tiepolo, Massimo; Vannucci, Riccardo

    2010-04-01

    During its 1800-year-long persistent activity the Stromboli volcano has erupted a highly porphyritic (HP) volatile-poor scoriaceous magma and a low porphyritic (LP) volatile-rich pumiceous magma. The HP magma is erupted during normal Strombolian explosions and lava effusions, while the LP one is related to more energetic paroxysms. During the March-April 2003 explosive activity, Stromboli ejected two typologies of juvenile glassy ashes, namely highly vesicular LP shards and volatile-poor HP shards. Their textural and in situ chemical characteristics are used to unravel mutual relationships between HP and LP magmas, as well as magma dynamics within the shallow plumbing system. The mantle-normalized trace element patterns of both ash types show the typical arc-lava pattern; however, HP glasses possess incompatible element concentrations higher than LP glasses, along with Sr and Eu negative anomalies. HP shards are generally characterized by higher Li contents (to ~20 ppm) and lower δ7Li values (+1.2 to -3.8‰) with respect to LP shards (Li contents of 7-14 ppm and δ7Li ranging between +4.6 and +0.9‰). Fractional crystallization models based on major and trace element compositions, combined with a degassing model based on open-system Rayleigh distillation and on the assumption that melt/fluidDLi > 1, show that abundant (~30%) plagioclase precipitation and variable degrees of degassing can lead the more primitive LP magma to evolve toward a differentiated (isotopically lighter) HP magma ponding in the upper conduit and undergoing slow continuous degassing-induced crystallization. This study also evidences that in March 2003 Stromboli volcano poured out a small early volume of LP magma that traveled slower within the conduit with respect to later and larger volumes of fast ascending LP magma erupted during the April 5 paroxysm. The different ascent rates and cooling rates of the two LP magma batches (i.e., pre- and post-paroxysm) resulted in small, but detectable

  9. Magmatic vapor source for sulfur dioxide released during volcanic eruptions: Evidence from Mount Pinatubo

    Science.gov (United States)

    Wallace, P.J.; Gerlach, T.M.

    1994-01-01

    Sulfur dioxide (SO2) released by the explosive eruption of Mount Pinatubo on 15 June 1991 had an impact on climate and stratospheric ozone. The total mass of SO2 released was much greater than the amount dissolved in the magma before the eruption, and thus an additional source for the excess SO2 is required. Infrared spectroscopic analyses of dissolved water and carbon dioxide in glass inclusions from quartz phenocrysts demonstrate that before eruption the magma contained a separate, SO2-bearing vapor phase. Data for gas emissions from other volcanoes in subduction-related arcs suggest that preeruptive magmatic vapor is a major source of the SO2 that is released during many volcanic eruptions.

  10. Evidence for hibernation from a statistical analysis of nova eruption amplitudes

    International Nuclear Information System (INIS)

    Vogt, N.

    1990-01-01

    This study is based on a sample of 97 well-observed galactic novae. First, a linear relation between eruption amplitude and decay time was determined. The residuals from this relation were analyzed for variations of the luminosities of old novae as a function of the time interval between eruption and observation in quiescence. Between 35 and 10 yr before eruption, a marginal increase in brightness may be present. However, in the last decade, four novae were found in an extremely faint low state. During the first 130 yr after the eruption, galactic novae show a slow decrease in brightness with a slope of 2.1 + or - 0.6 mag per century. The results are interpreted in terms of secular variations of the mass transfer rate as expected from the hibernation model. 20 refs

  11. Constraining Eruptive Conditions From Lava Flow Morphometry: A Case Study With Field Evidence

    Science.gov (United States)

    Bowles, Z. R.; Clarke, A.; Greeley, R.

    2007-12-01

    Volcanism is widely recognized as one of the primary factors affecting the surfaces of solid planets and satellites throughout the solar system. Basaltic lava is thought to be the most common composition based on observed features typical of basaltic eruptions found on Earth. Lava flows are one of the most easily recognizable landforms on planetary surfaces and their features may provide information about eruption dynamics, lava rheology, and potential hazards. More recently, researchers have taken a multi-faceted approach to combine remote sensing, field observations and quantitative modeling to constrain volcanic activity on Earth and other planets. Here we test a number of published models, including empirically derived relationships from Mt. Etna and Kilauea, models derived from laboratory experiments, and theoretical models previously applied to remote sensing of planetary surfaces, against well-documented eruptions from the literature and field observations. We find that the Graetz (Hulme and Felder, 1977, Phil.Trans., 285, 227 - 234) method for estimating effusion rates compares favorably with published eruption data, while, on the other hand, inverting lava flow length prediction models to estimate effusion rates leads to several orders of magnitude in error. The Graetz method also better constrains eruption duration. Simple radial spreading laws predict Hawaiian lava flow lengths quite well, as do using the thickness of the lava flow front and chilled crust. There was no observed difference between results from models thought to be exclusive to aa or pahoehoe flow fields. Interpreting historic conditions should therefore follow simple relationships to observable morphologies no matter the composition or surface texture. We have applied the most robust models to understand the eruptive conditions and lava rheology of the Batamote Mountains near Ajo, AZ, an eroded shield volcano in southern Arizona. We find effusion rates on the order of 100 - 200 cubic

  12. Expanding and Contracting Coronal Loops as Evidence of Vortex Flows Induced by Solar Eruptions

    Energy Technology Data Exchange (ETDEWEB)

    Dudík, J. [Astronomical Institute of the Czech Academy of Sciences, Fričova 298, 251 65 Ondřejov (Czech Republic); Zuccarello, F. P.; Aulanier, G.; Schmieder, B.; Démoulin, P., E-mail: jaroslav.dudik@asu.cas.cz [LESIA, Observatoire de Paris, Psl Research University, CNRS, Sorbonne Universits, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cit, 5 place Jules Janssen, F-92195 Meudon (France)

    2017-07-20

    Eruptive solar flares were predicted to generate large-scale vortex flows at both sides of the erupting magnetic flux rope. This process is analogous to a well-known hydrodynamic process creating vortex rings. The vortices lead to advection of closed coronal loops located at the peripheries of the flaring active region. Outward flows are expected in the upper part and returning flows in the lower part of the vortex. Here, we examine two eruptive solar flares, the X1.1-class flare SOL2012-03-05T03:20 and the C3.5-class SOL2013-06-19T07:29. In both flares, we find that the coronal loops observed by the Atmospheric Imaging Assembly in its 171 Å, 193 Å, or 211 Å passbands show coexistence of expanding and contracting motions, in accordance with the model prediction. In the X-class flare, multiple expanding and contracting loops coexist for more than 35 minutes, while in the C-class flare, an expanding loop in 193 Å appears to be close by and cotemporal with an apparently imploding loop arcade seen in 171 Å. Later, the 193 Å loop also switches to contraction. These observations are naturally explained by vortex flows present in a model of eruptive solar flares.

  13. New proximal tephras at Somma-Vesuvius: evidences of a pre-caldera, large (?) explosive eruption

    Science.gov (United States)

    Sparice, Domenico; Scarpati, Claudio; Mazzeo, Fabio Carmine; Petrosino, Paola; Arienzo, Ilenia; Gisbert, Guillem; Petrelli, Maurizio

    2017-04-01

    A 5 m thick pyroclastic and volcaniclastic sequence, never reported before, comprising a pumice fall deposit has been recognized in a disused quarry near Pollena Trocchia, on the NW slope of Somma-Vesuvius. It is composed of three stratigraphic units: a pumice fall deposit that underlies a pyroclastic density current deposit; they are overlain by a volcaniclastic unit emplaced during a quiescent period of the volcano. The pyroclastic deposits are separated by a horizon of reworked material indicating the emplacement from two distinct eruptive events. The pumice fall deposit has been subject of a detailed investigation. It consists of an ash bed overlaid by a roughly stratified pumice fall layer. The presence of ballistic clasts indicates the proximal nature of this deposit and its stratigraphic position below the Pomici di Base (22 ka) Plinian deposit allows constraining its age to the pre-caldera period (22-39 ky) of activity of Somma-Vesuvius. Samples have been collected in order to perform sedimentological (grain size and componentry), geochemical and isotopic analyses. Samples range from moderately to poorly sorted and show a trachytic composition. The comparison with literature data of compatible deposits vented from Somma-Vesuvius (Schiava, Taurano and Codola eruptions as well as borehole data) allows excluding any correlation with already known Vesuvian products suggesting that the analysed products are ascribable to a new, pre-caldera, explosive eruption. We name this new event ;Carcavone eruption;. Based on thickness, maximum lithic clasts and orientation of impact sags, showing a provenance from SE, we envisage the emplacement from a Plinian style eruption vented in the northern sector of the current caldera.

  14. A critical evaluation of the evidence for multiple Late Pleistocene eruptions of Laacher See Volcano

    DEFF Research Database (Denmark)

    Zernack, Anke Verena; Hoggard, Christian Steven; Sauer, Florian Rudolf

    The c. 12,900 BP Plinian eruption of Laacher See Volcano is one of the largest known volcanic events of the Late Pleistocene in the Northern Hemisphere. It buried proximal areas under tens of meters of pyroclastic flow, surge and fallout deposits and deposited a widespread tephra layer across much...... of Europe. Based on changes in tephra composition, bedrock lithology, vent location and eruptive mechanism, the proximal sequence was subdivided into Lower (LLST), Middle (MLST-A, - B and -C) and Upper (ULST) Laacher See Tephra. The geochemical variation allowed fingerprinting the products of the different...... fan identified to the south-west (exclusively ULST). Early studies reported the occurrence of Laacher See Tephra from the Baltic Sea to northern Italy and Belgium. However, since then advances in methodology, in particular regarding identification of cryptotephras, and a better understanding...

  15. Pre-eruptive magmatic conditions at Augustine Volcano, Alaska, 2006: Evidence from amphibole geochemistry and textures

    Science.gov (United States)

    De Angelis, Sarah; Larsen, Jessica D; Coombs, Michelle L.

    2013-01-01

    Variations in the geochemistry and texture of amphibole phenocrysts erupted from Augustine Volcano in 2006 provide new insights into pre- and syn-eruptive magma storage and mixing. Amphiboles are rare but present in all magma compositions (low- to high-silica andesites) from the 3 month long eruption. Unzoned magnesiohornblende in the high- and low-silica andesites exhibit limited compositional variability, relatively high SiO2 (up to 49·7 wt %), and relatively low Al2O3 (temperature-dependent substitutions. Both high- and low-silica andesites represent remnant magmas that were stored in the shallow crust at 4–8 km depth, remaining distinct owing to a complex subsurface plumbing system. Intermediate-silica andesites and quenched mafic inclusions represent pre-eruptive hybrids of resident high- and low-silica andesite magmas and an intruding basalt. Amphiboles in explosive phase high-silica andesites are largely euhedral and unreacted, consistent with the high magma flux rates from depth during this phase (up to 13 800 m3 s–1). Phenocrysts from the other lithologies have reaction rims that range from 1 to >1000 μm in thickness. Reaction rim microlite sizes correlate with reaction rim thicknesses. Reaction rims 80 μm thick contain microlites 10–100 μm in length. Differentiating between heating- and decompression-induced amphibole reaction rim formation is problematic because of a lack of experimental constraints. We attempt a new approach to assessing reaction rim formation, based on a kinetic theory of crystal nucleation and growth, in which the differences in reaction rim textures represent different degrees of amphibole disequilibrium. Large crystals and low number densities suggest relatively lower levels of disequilibrium resulting in growth-dominated crystallization. Smaller crystals and larger number densities are indicative of higher nucleation rates and a high driving force.

  16. The 2010 Eyjafjallajökull volcanic summit eruption: evidences from ash-leachates analysis and ground deposition fluxes

    Science.gov (United States)

    Bagnato, E.; Aiuppa, A.; Bertagnini, A.; Bonadonna, C.; Cioni, R.; Pedone, M.; Pistolesi, M.

    2012-04-01

    The Eyjafjallajökull 2010 eruption was an extraordinary event in that it led to widespread over Europe. Volcanic processes which lead to eruptions can be investigated by monitoring a variety of parameters, including the composition of ash leachates. Fine-grained tephra erupted from active vents, and transported through volcanic plumes, can adsorbs, and therefore rapidly scavenge, volatile elements such as S, halogens, and metal species in the form of soluble salts adhering to ash surfaces. Analysis of such water-soluble phases is a suitable complement for the remote sensing of volcanic gases at inaccessible volcanoes, like Eyjafjallajökull. The 2010 Eyjafjallajökull eruption developed in four main phases, whose difference in gas chemistry and products has been marked in ash-leachates data too. The recurrent ash fallout provided a unique opportunity to characterize the compositional features of ash leachates, and to identify their relation (if any) with the eruptive activity styles of the volcano. By these considerations, we report on the chemical composition of leachates of 20 volcanic ash samples deposited during the most explosive Eyjafjallajökull activities (from 14 April to 8 May) and during the lava fountaining event (on 26th March 2010). We found that ash-leachate solutions are dominated - among cations - by Na and Ca, while they display nearly equal S : Cl : F abundances (mean S/Cl and S/F molar ratios of 0.85 and 0.33, respectively), as characteristic of divergent-plate and within-plate volcanism. The strong correlations between leached Ca - F , Ca - SO4, and Na - Cl (r2 = 0.7 - 0.9), suggest that fluorite, anhydrite, and halite are the most likely soluble surface minerals formed in the plume (and therefore leached during our experiments), as also reported at many active volcanoes. Our data bring evidence for variations in S and halogens proportions, with samples from 5 - 8th May which show the highest S/Cl and lowest Cl/F ratios. By combining the

  17. Eruption and deposition of the Fisher Tuff (Alaska)--Evidence for the evolution of pyroclastic flows

    Science.gov (United States)

    Burgisser, Alain; Gardner, J.E.; Stelling, P.

    2007-01-01

    Recognition that the Fisher Tuff (Unimak Island, Alaska) was deposited on the leeside of an ∼500–700‐m‐high mountain range (Tugamak Range) more than 10 km away from its source played a major role in defining pyroclastic flows as momentum‐driven currents. We reexamined the Fisher Tuff to evaluate whether deposition from expanded turbulent clouds can better explain its depositional features. We studied the tuff at 89 sites and sieved bulk samples from 27 of those sites. We find that the tuff consists of a complex sequence of deposits that record the evolution of the eruption from a buoyant plume (22 km) that deposited ∼0.2 km3 of dacite magma as a pyroclastic fall layer to erupting ∼10–100 km3 of andesitic magma as Scoria‐rich pyroclastic falls and flows that were mainly deposited to the north and northwest of the caldera, including those in valleys within the Tugamak Range. The distribution of the flow deposits and their welding, internal stratification, and the occurrence of lithic breccia all suggest that the pyroclastic flows were fed from a fountaining column that vented from an inclined conduit, the first time such a conduit has been recognized during a large‐volume caldera eruption. Pyroclastic flow deposits before and after the mountain range and thin veneer deposits high in the range are best explained by a flow that was stratified into a dense undercurrent and an overriding dilute turbulent cloud, from which deposition before the range was mainly from the undercurrent. When the flow ran into the mountain range, however, the undercurrent was blocked, but the turbulent cloud continued on. As the flow continued north, it restratified, forming another undercurrent. The Fisher Tuff thus records the passing of a flow that was significantly higher (800–1100 m thick) than the mountain range and thus did not require excessive momentum.

  18. Platyrrhine dental eruption sequences.

    Science.gov (United States)

    Henderson, Emily

    2007-10-01

    To determine dental eruption sequences of extant platyrrhines, 367 mandibles and maxillae of informative juvenile specimens from all 16 genera were scored for presence of permanent teeth including three intermediate eruption stages following Harvati (Am J Phys Anthropol 112 (2000) 69-85). The timing of molar eruption relative to that of the anterior dentition is variable in platyrrhines. Aotus is precocious, with all molars erupting in succession before replacement of any deciduous teeth, while Cebus is delayed in M2-3 eruption relative to I1-2. Callitrichines have a distinct tendency toward delayed canine and premolar development. Platyrrhine eruption sequences presented here show some evidence of conformity to Schultz's Rule, with relatively early replacement of deciduous dentition in "slower"-growing animals. The relationship of dental eruption sequences to degree of folivory, body mass, brain mass, and dietary quality is also examined. The early eruption of molars relative to anterior teeth in Pithecia, Chiropotes, and Cacajao, in comparison to genera such as Ateles, Lagothrix, and Alouatta, showing relatively later eruption of the molars, appears to be consistent with current phylogenetic hypotheses. Schultz (Am J Phys Anthropol 19 (1935) 489-581) postulated early relative molar eruption as the primitive dental eruption schedule for primates. The extremely early molar eruption of Aotus versus Callicebus (where both incisors erupt before M2 and M3, with M3 usually last) may lend support to the status of Aotus as a basal taxon. The early relative molar eruption of the fossil platyrrhine species Branisella boliviana is also consistent with this hypothesis (Takai et al.: Am J Phys Anthropol 111 (2000) 263-281). (c) 2007 Wiley-Liss, Inc.

  19. Salt shell fallout during the ash eruption at the Nakadake crater, Aso volcano, Japan: evidence of an underground hydrothermal system surrounding the erupting vent

    Science.gov (United States)

    Shinohara, Hiroshi; Geshi, Nobuo; Yokoo, Akihiko; Ohkura, Takahiro; Terada, Akihiko

    2018-03-01

    A hot and acid crater lake is located in the Nakadake crater, Aso volcano, Japan. The volume of water in the lake decreases with increasing activity, drying out prior to the magmatic eruptions. Salt-rich materials of various shapes were observed, falling from the volcanic plume during the active periods. In May 2011, salt flakes fell from the gas plume emitted from an intense fumarole when the acid crater lake was almost dry. The chemical composition of these salt flakes was similar to those of the salts formed by the drying of the crater lake waters, suggesting that they originated from the crater lake water. The salt flakes are likely formed by the drying up of the crater lake water droplets sprayed into the plume by the fumarolic gas jet. In late 2014, the crater lake dried completely, followed by the magmatic eruptions with continuous ash eruptions and intermittent Strombolian explosions. Spherical hollow salt shells were observed on several occasions during and shortly after the weak ash eruptions. The chemical composition of the salt shells was similar to the salts formed by the drying of the crater lake water. The hollow structure of the shells suggests that they were formed by the heating of hydrothermal solution droplets suspended by a mixed stream of gas and ash in the plume. The salt shells suggest the existence of a hydrothermal system beneath the crater floor, even during the course of magmatic eruptions. Instability of the magmatic-hydrothermal interface can cause phreatomagmatic explosions, which often occur at the end of the eruptive phase of this volcano.

  20. Two Categories of Apparent Tornado-like Prominences

    Science.gov (United States)

    Martin, Sara F.; Venkataramanasastry, Aparna

    2014-06-01

    Two categories of solar prominences have been described in the literature as having a pattern of mass motions and/or a shape similar to terrestrial tornados. We first identify the two categories associated with prominences in the historic literature and then show that counterparts do exist for both in recent literature but one has not been called a tornado prominence. One category described as being similar to tornados is associated with the barbs of quiescent filaments but barbs appear to have rotational motion only under special conditions. H alpha Doppler observations from Helio Research confirm that this category is an illusion in our mind’s eye resulting from counterstreaming in the large barbs of quiescent filaments. The second category is a special case of rotational motion occurring during the early stages of some erupting prominences, in recent years called the roll effect in erupting prominences. In these cases, the eruption begins with the sideways rolling of the top of a prominence. As the eruption proceeds the rolling motion propagates down one leg or both legs of an erupting prominence depending on whether the eruption is asymmetric or symmetric respectively. As an asymmetric eruption proceeds, the longer lasting leg becomes nearly vertical and has true rotational motion. If only this phase of the eruption was observed, as in the historic cases, it was called a tornado prominence and spectra recorded in these cases provide proof of the rotational motion. When one observes an entire eruption which exhibits the rolling motion, as accomplished at Helio Research, the similarity to a tornado is lost because the event as a whole has quite a different nature and the analogy to a terrestrial tornado not longer appears suitable or helpful in understanding the observed and deduced physical processes. Our conclusion is that there are no solar prominences with motions that are usefully described as tornado or tornado-like events aside from the fun of observing

  1. Subaqueous early eruptive phase of the late Aptian Rajmahal volcanism, India: Evidence from volcaniclastic rocks, bentonite, black shales, and oolite

    Directory of Open Access Journals (Sweden)

    Naresh C. Ghose

    2017-07-01

    of grey and black shale/mudstone in the lower one-third of the succession across the entire Rajmahal basin provides unequivocal evidence of a shallow-marine continental shelf-type environment. Alignment of the Rajmahal eruptive centers with a major N–S mid-Neoproterozoic lineament and the presence of a gravity high on the RVP suggest a tectonic control for the eruption of melts associated with the Kerguelen plume that was active in a post-Gondwana rift between India and Australia-Antarctica.

  2. SOLAR MAGNETIZED TORNADOES: ROTATIONAL MOTION IN A TORNADO-LIKE PROMINENCE

    International Nuclear Information System (INIS)

    Su, Yang; Veronig, Astrid; Temmer, Manuela; Vanninathan, Kamalam; Gömöry, Peter; Wang, Tongjiang; Gan, Weiqun; Li, YouPing

    2014-01-01

    Su et al. proposed a new explanation for filament formation and eruption, where filament barbs are rotating magnetic structures driven by underlying vortices on the surface. Such structures have been noticed as tornado-like prominences when they appear above the limb. They may play a key role as the source of plasma and twist in filaments. However, no observations have successfully distinguished rotational motion of the magnetic structures in tornado-like prominences from other motions such as oscillation and counter-streaming plasma flows. Here we report evidence of rotational motions in a tornado-like prominence. The spectroscopic observations in two coronal lines were obtained from a specifically designed Hinode/EIS observing program. The data revealed the existence of both cold and million-degree-hot plasma in the prominence leg, supporting the so-called prominence-corona transition region. The opposite velocities at the two sides of the prominence and their persistent time evolution, together with the periodic motions evident in SDO/AIA dark structures, indicate a rotational motion of both cold and hot plasma with a speed of ∼5 km s –1

  3. SOLAR MAGNETIZED TORNADOES: ROTATIONAL MOTION IN A TORNADO-LIKE PROMINENCE

    Energy Technology Data Exchange (ETDEWEB)

    Su, Yang; Veronig, Astrid; Temmer, Manuela; Vanninathan, Kamalam [IGAM-Kanzelhöhe Observatory, Institute of Physics, University of Graz, Universitätsplatz 5, A-8010 Graz (Austria); Gömöry, Peter [Astronomical Institute of the Slovak Academy of Sciences, SK-05960 Tatranská Lomnica (Slovakia); Wang, Tongjiang [Department of Physics, the Catholic University of America, Washington, DC 20064 (United States); Gan, Weiqun; Li, YouPing, E-mail: yang.su@uni-graz.at [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

    2014-04-10

    Su et al. proposed a new explanation for filament formation and eruption, where filament barbs are rotating magnetic structures driven by underlying vortices on the surface. Such structures have been noticed as tornado-like prominences when they appear above the limb. They may play a key role as the source of plasma and twist in filaments. However, no observations have successfully distinguished rotational motion of the magnetic structures in tornado-like prominences from other motions such as oscillation and counter-streaming plasma flows. Here we report evidence of rotational motions in a tornado-like prominence. The spectroscopic observations in two coronal lines were obtained from a specifically designed Hinode/EIS observing program. The data revealed the existence of both cold and million-degree-hot plasma in the prominence leg, supporting the so-called prominence-corona transition region. The opposite velocities at the two sides of the prominence and their persistent time evolution, together with the periodic motions evident in SDO/AIA dark structures, indicate a rotational motion of both cold and hot plasma with a speed of ∼5 km s{sup –1}.

  4. Solar Magnetized Tornadoes: Rotational Motion in a Tornado-like Prominence

    Science.gov (United States)

    Su, Yang; Gömöry, Peter; Veronig, Astrid; Temmer, Manuela; Wang, Tongjiang; Vanninathan, Kamalam; Gan, Weiqun; Li, YouPing

    2014-04-01

    Su et al. proposed a new explanation for filament formation and eruption, where filament barbs are rotating magnetic structures driven by underlying vortices on the surface. Such structures have been noticed as tornado-like prominences when they appear above the limb. They may play a key role as the source of plasma and twist in filaments. However, no observations have successfully distinguished rotational motion of the magnetic structures in tornado-like prominences from other motions such as oscillation and counter-streaming plasma flows. Here we report evidence of rotational motions in a tornado-like prominence. The spectroscopic observations in two coronal lines were obtained from a specifically designed Hinode/EIS observing program. The data revealed the existence of both cold and million-degree-hot plasma in the prominence leg, supporting the so-called prominence-corona transition region. The opposite velocities at the two sides of the prominence and their persistent time evolution, together with the periodic motions evident in SDO/AIA dark structures, indicate a rotational motion of both cold and hot plasma with a speed of ~5 km s-1.

  5. Grammar and discourse prominence

    DEFF Research Database (Denmark)

    Christensen, Marie Herget; Vinther, Nicoline Munck; Kristensen, Line Burholt

    in Danish, the lexicon-grammar contrast is a more important cue to discourse prominence (foreground vs. background status) than focalization (by means of focus particles). BOYE, K. & HARDER, P. 2012. A usage-based theory of grammatical status and grammaticalization. Language, 88, 1-44. RENSINK, R. A., O...

  6. Brain architecture of the largest living land arthropod, the Giant Robber Crab Birgus latro (Crustacea, Anomura, Coenobitidae: evidence for a prominent central olfactory pathway?

    Directory of Open Access Journals (Sweden)

    Krieger Jakob

    2010-09-01

    Full Text Available Abstract Background Several lineages within the Crustacea conquered land independently during evolution, thereby requiring physiological adaptations for a semi-terrestrial or even a fully terrestrial lifestyle. Birgus latro Linnaeus, 1767, the giant robber crab or coconut crab (Anomura, Coenobitidae, is the largest land-living arthropod and inhabits Indo-Pacific islands such as Christmas Island. B. latro has served as a model in numerous studies of physiological aspects related to the conquest of land by crustaceans. From an olfactory point of view, a transition from sea to land means that molecules need to be detected in gas phase instead of in water solution. Previous studies have provided physiological evidence that terrestrial hermit crabs (Coenobitidae such as B. latro have a sensitive and well differentiated sense of smell. Here we analyze the brain, in particular the olfactory processing areas of B. latro, by morphological analysis followed by 3 D reconstruction and immunocytochemical studies of synaptic proteins and a neuropeptide. Results The primary and secondary olfactory centers dominate the brain of B. latro and together account for ca. 40% of the neuropil volume in its brain. The paired olfactory neuropils are tripartite and composed of more than 1,000 columnar olfactory glomeruli, which are radially arranged around the periphery of the olfactory neuropils. The glomeruli are innervated ca. 90,000 local interneurons and ca. 160,000 projection neurons per side. The secondary olfactory centers, the paired hemiellipsoid neuropils, are targeted by the axons of these olfactory projection neurons. The projection neuron axonal branches make contact to ca. 250.000 interneurons (per side associated with the hemiellipsoid neuropils. The hemiellipsoid body neuropil is organized into parallel neuropil lamellae, a design that is quite unusual for decapod crustaceans. The architecture of the optic neuropils and areas associated with antenna two

  7. Brain architecture of the largest living land arthropod, the Giant Robber Crab Birgus latro (Crustacea, Anomura, Coenobitidae): evidence for a prominent central olfactory pathway?

    Science.gov (United States)

    2010-01-01

    Background Several lineages within the Crustacea conquered land independently during evolution, thereby requiring physiological adaptations for a semi-terrestrial or even a fully terrestrial lifestyle. Birgus latro Linnaeus, 1767, the giant robber crab or coconut crab (Anomura, Coenobitidae), is the largest land-living arthropod and inhabits Indo-Pacific islands such as Christmas Island. B. latro has served as a model in numerous studies of physiological aspects related to the conquest of land by crustaceans. From an olfactory point of view, a transition from sea to land means that molecules need to be detected in gas phase instead of in water solution. Previous studies have provided physiological evidence that terrestrial hermit crabs (Coenobitidae) such as B. latro have a sensitive and well differentiated sense of smell. Here we analyze the brain, in particular the olfactory processing areas of B. latro, by morphological analysis followed by 3 D reconstruction and immunocytochemical studies of synaptic proteins and a neuropeptide. Results The primary and secondary olfactory centers dominate the brain of B. latro and together account for ca. 40% of the neuropil volume in its brain. The paired olfactory neuropils are tripartite and composed of more than 1,000 columnar olfactory glomeruli, which are radially arranged around the periphery of the olfactory neuropils. The glomeruli are innervated ca. 90,000 local interneurons and ca. 160,000 projection neurons per side. The secondary olfactory centers, the paired hemiellipsoid neuropils, are targeted by the axons of these olfactory projection neurons. The projection neuron axonal branches make contact to ca. 250.000 interneurons (per side) associated with the hemiellipsoid neuropils. The hemiellipsoid body neuropil is organized into parallel neuropil lamellae, a design that is quite unusual for decapod crustaceans. The architecture of the optic neuropils and areas associated with antenna two suggest that B. latro has

  8. Brain architecture of the largest living land arthropod, the Giant Robber Crab Birgus latro (Crustacea, Anomura, Coenobitidae): evidence for a prominent central olfactory pathway?

    Science.gov (United States)

    Krieger, Jakob; Sandeman, Renate E; Sandeman, David C; Hansson, Bill S; Harzsch, Steffen

    2010-09-10

    Several lineages within the Crustacea conquered land independently during evolution, thereby requiring physiological adaptations for a semi-terrestrial or even a fully terrestrial lifestyle. Birgus latro Linnaeus, 1767, the giant robber crab or coconut crab (Anomura, Coenobitidae), is the largest land-living arthropod and inhabits Indo-Pacific islands such as Christmas Island. B. latro has served as a model in numerous studies of physiological aspects related to the conquest of land by crustaceans. From an olfactory point of view, a transition from sea to land means that molecules need to be detected in gas phase instead of in water solution. Previous studies have provided physiological evidence that terrestrial hermit crabs (Coenobitidae) such as B. latro have a sensitive and well differentiated sense of smell. Here we analyze the brain, in particular the olfactory processing areas of B. latro, by morphological analysis followed by 3 D reconstruction and immunocytochemical studies of synaptic proteins and a neuropeptide. The primary and secondary olfactory centers dominate the brain of B. latro and together account for ca. 40% of the neuropil volume in its brain. The paired olfactory neuropils are tripartite and composed of more than 1,000 columnar olfactory glomeruli, which are radially arranged around the periphery of the olfactory neuropils. The glomeruli are innervated ca. 90,000 local interneurons and ca. 160,000 projection neurons per side. The secondary olfactory centers, the paired hemiellipsoid neuropils, are targeted by the axons of these olfactory projection neurons. The projection neuron axonal branches make contact to ca. 250.000 interneurons (per side) associated with the hemiellipsoid neuropils. The hemiellipsoid body neuropil is organized into parallel neuropil lamellae, a design that is quite unusual for decapod crustaceans. The architecture of the optic neuropils and areas associated with antenna two suggest that B. latro has visual and

  9. Silicate melt inclusion evidence for extreme pre-eruptive enrichment and post-eruptive depletion of lithium in silicic volcanic rocks of the western United States: implications for the origin of lithium-rich brines

    Science.gov (United States)

    Hofstra, Albert H.; Todorov, T.I.; Mercer, C.N.; Adams, D.T.; Marsh, E.E.

    2013-01-01

    To evaluate whether anatectic and/or highly fractionated lithophile element-enriched rhyolite tuffs deposited in arid lacustrine basins lose enough lithium during eruption, lithification, and weathering to generate significant Li brine resources, pre-eruptive melt compositions, preserved in inclusions, and the magnitude of post-eruptive Li depletions, evident in host rhyolites, were documented at six sites in the western United States. Each rhyolite is a member of the bimodal basalt-rhyolite assemblage associated with extensional tectonics that produced the Basin and Range province and Rio Grande rift, an evolving pattern of closed drainage basins, and geothermal energy or mineral resources. Results from the 0.8 Ma Bishop tuff (geothermal) in California, 1.3 to 1.6 Ma Cerro Toledo and Upper Bandelier tephra (geothermal) and 27.9 Ma Taylor Creek rhyolite (Sn) in New Mexico, 21.7 Ma Spor Mountain tuff (Be, U, F) and 24.6 Ma Pine Grove tuff (Mo) in Utah, and 27.6 Ma Hideaway Park tuff (Mo) in Colorado support the following conclusions. Melt inclusions in quartz phenocrysts from rhyolite tuffs associated with hydrothermal deposits of Sn, Mo, and Be are extremely enriched in Li (1,000s of ppm); those from Spor Mountain have the highest Li abundance yet recorded (max 5,200 ppm, median 3,750 ppm). Forty-five to 98% of the Li present in pre-eruptive magma was lost to the environment from these rhyolite tuffs. The amount of Li lost from the small volumes (1–10 km3) of Li-enriched rhyolite deposited in closed basins is sufficient to produce world-class Li brine resources. After each eruption, meteoric water leaches Li from tuff, which drains into playas, where it is concentrated by evaporation. The localized occurrence of Li-enriched rhyolites may explain why brines in arid lacustrine basins seldom have economic concentrations of Li. Considering that hydrothermal deposits of Sn, Mo, Be, U, and F may indicate potential for Li brines in nearby basins, we surmise that the

  10. H(alpha) Proxies for EIT Crinkles: Further Evidence for Preflare "Breakout"-Type Activity in an Ejective Solar Eruption

    Science.gov (United States)

    Sterling, Alphonse C.; Qiu, Jiong; Wang, Haimin; Moore, Ronald L.

    2001-01-01

    We present H(alpha) observations from Big Bear Solar Observatory of an eruptive flare in NOAA Active Region 8210, occurring near 22:30 UT on 1998 May 1. Previously, using the Extreme Ultraviolet Imaging Telescope (EIT) on the Solar and Heliospheric Observatory (SOHO) spacecraft, we found that a pattern of transient, localized brightenings, which we call 'EIT crinkles,' appears in the neighborhood of the eruption near the time of flare onset. These EIT crinkles occur at a location in the active region well separated from the sheared core magnetic fields, which is where the most intense features of the eruption are concentrated. We also previously found that high-cadence images from the Soft X-ray Telescope (SXT) on Yohkoh indicate that soft X-ray intensity enhancements in the core begin after the start of the EIT crinkles. With the H(alpha) data, we find remote flare brightening counterparts to the EIT crinkles. Light curves as functions of time of various areas of the active region show that several of the remote flare brightenings undergo intensity increases prior to the onset of principal brightenings in the core region, consistent with our earlier findings from EIT and SXT data. These timing relationships are consistent with the eruption onset mechanism known as the breakout model, introduced by Antiochos and colleagues, which proposes that eruptions begin with reconnection at a magnetic null high above the core region. Our observations are also consistent with other proposed mechanisms that do not involve early reconnection in the core region. As a corollary, our observations are not consistent with the so-called tether-cutting models, which say that the eruption begins with reconnection in the core. The H(alpha) data further show that a filament in the core region becomes activated near the time of EIT crinkle onset, but little if any of the filament actually erupts, despite the presence of a halo coronal mass ejection (CME) associated with this event.

  11. Radar "Stealth" terrain on Mars: Evidence of a pyroclastic eruption west-northwest of Arsia Mons volcano

    Science.gov (United States)

    Zimbelman, James R.; Edgett, Kenneth S.

    1994-05-01

    Over 1,000,000 km2 of the equatorial surface of Mars west of the Arsia Mons volcano displays no 3.5-cm radar echo to the very low level of the radar system noise for the Very Large Array; the area displaying this unique property has been terms "Stealth" (Muhleman et al., Science 253, 1508-1513, 1991). Here we note that the eastern margin of the Stealth terrain closely corresponds to materials previously interpreted to be pyroclastic deposits superposed on the lobe-shaped "landslide" terrain on the lower western flanks of Arsia Mons. The west-northwest orientation of the Stealth region is identical to the orientation of both bright and dark wind streaks in the area. However, it seems unlikely that aeolian processes alone could have produced the unique Stealth area because it occurs within a much larger region with relatively uniform properties at thermal infrared wavelengths. We reconcile these observations with the hypothesis that the Stealth region corresponds to an extensive mantle of pyroclastics (locally > 2 m thick) which has subsequently been covered by a more pervasive aeolian dust mantle (generally > 10 cm thick). The proposed pyroclastic eruption cloud traveled down the shallow local slope, consistent with the orientation of the dominant winds in the area at present. The unique Stealth radar response then results from signal loss within copious quantities of fine-grained ash particles (lacking volume scatterers), hidden from direct exposure beneath the more pervasive (but relatively thin) dust mantle that coats the entire Tharsis region. We speculate that the Stealth material stratigraphically overlays all geologic terrains evidence in Viking Orbiter images of the Tharsis region.

  12. Prominence Mass Supply and the Cavity

    Science.gov (United States)

    Schmit, Donald J.; Gibson, S.; Luna, M.; Karpen, J.; Innes, D.

    2013-01-01

    A prevalent but untested paradigm is often used to describe the prominence-cavity system; the cavity is under-dense because it it evacuated by supplying mass to the condensed prominence. The thermal non-equilibrium (TNE) model of prominence formation offers a theoretical framework to predict the thermodynamic evolutin of the prominence and the surrounding corona. We examine the evidence for a prominence-cavity connection by comparing the TNE model and diagnostics of dynamic extreme ultraviolet (EUV) emission surrounding the prominence, specifically prominence horns. Horns are correlated extensions of prminence plasma and coronal plasma which appear to connect the prominence and cavity. The TNE model predicts that large-scale brightenings will occur in the Solar Dynamics Observatory Atmospheric Imaging Assembly 171 A badpass near he prominence that are associated with the cooling phase of condensation formation. In our simulations, variations in the magnitude of footpoint heating lead to variations in the duration, spatial scale, and temporal offset between emission enhancements in the other EUV bandpasses. While these predictions match well a subset of the horn observations, the range of variations in the observed structures is not captured by the model. We discuss the implications of one-dimensional loop simulations for the three-dimensional time-averaged equilibrium in the prominence and the cavity. Evidence suggests that horns are likely caused by condensing prominence plasma, but the larger question of whether this process produces a density-depleted cavity requires a more tightly constrained model of heating and better knowledge of the associated magnetic structure.

  13. Seasonality of volcanic eruptions

    Science.gov (United States)

    Mason, B.; Pyle, D.; Dade, B.; Jupp, T.

    2003-04-01

    An analysis of volcanic activity in the last three hundred years reveals that the frequency of onset of volcanic eruptions varies systematically with the time of year. We analysed the Smithsonian catalogue of more than 3200 subaerial eruptions recorded during the last 300 years. We also investigated continuous records, which are not part of the general catalogue, of individual explosions at Sakurajima volcano (Japan, 150 events per year since 1955) and Semeru (Indonesia, 100,000 events during the period 1997-2000). A higher proportion (as much as 18 percent of the average monthly rate) of eruptions occur worldwide between December and March. This observation is statistically significant at above the 99 percent level. This pattern is independent of the time interval considered, and emerges whether individual eruptions are counted with equal weight or with weights proportional to event explosivity. Elevated rates of eruption onset in boreal winter months are observed in northern and southern hemispheres alike, as well as in most volcanically-active regions including, most prominently, the 'Ring of Fire' surrounding the Pacific basin. Key contributors to this regional pattern include volcanoes in Central and South America, the volcanic provinces of the northwest Pacific rim, Indonesia and the southwest Pacific basin. On the smallest spatial scales, some individual volcanoes for which detailed histories exist exhibit peak levels in eruption activity during November-January. Seasonality is attributed to one or more mechanisms associated with the annual hydrological cycle, and may correspond to the smallest time-scale over which fluctuations in stress due to the redistribution of water-masses are felt by the Earth's crust. Our findings have important ramifications for volcanic risk assessment, and offer new insight into possible changes in volcanic activity during periods of long-term changes in global sea level.

  14. Geochemistry of the 1989-1990 eruption of redoubt volcano: Part II. Evidence from mineral and glass chemistry

    Science.gov (United States)

    Swanson, S.E.; Nye, C.J.; Miller, T.P.; Avery, V.F.

    1994-01-01

    Early stages (December 1989) of the 1989-1990 eruption of Redoubt Volcano produced two distinct lavas. Both lavas are high-silica andesites with a narrow range of bulk composition (58-64 wt.%) and similar mineralogies (phenocrysts of plagioclase, hornblende, augite, hypersthene and FeTi oxides in a groundmass of the same phases plus glass). The two lavas are distinguished by groundmass glass compositions, one is dacitic and the other rhyolitic. Sharp boundaries between the two glasses in compositionally banded pumices, lack of extensive coronas on hornblende phenocrysts, and seismic data suggest that a magma-mixing event immediately preceeded the eruption in December 1989. Textural disequilibrium in the phenocrysts suggests both magmas (dacitic and rhyolitic glasses) had a mixing history prior to their interaction and eruption in 1989. Sievey plagioclase and overgrowths of magnetite on ilmenite are textures that are at least consistent with magma mixing. The presence of two hornblende compositions (one a high-Al pargasitic hornblende and one a low-Al magnesiohornblende) in both the dacitic and rhyolitic groundmasses indicates a mixing event to yield these two amphibole populations prior to the magma mixing in December 1989. The pargasitic hornblende and the presence of Ca-rich overgrowths in the sievey zones of the plagioclase together indicate at least one component of this earlier mixing event was a mafic magma, either a basalt or a basaltic andesite. Eruptions in 1990 produced only andesite with a rhyolitic groundmass glass. Glass compositions in the 1990 andesite are identical to the rhyolitic glass in the 1989 andesite. Cognate xenoliths from the magma chamber (or conduit) are also found in the 1990 lavas. Magma mixing probably triggered the eruption in 1989. The eruption ended when this rather viscous (rhyolitic groundmass glass, magma capable of entraining sidewall xenoliths) magma stabalized within the conduit. ?? 1994.

  15. The 21,700 yr b.p. Lower Toluca Pumice Plinian Eruption of Nevado de Toluca Volcano (Mexico): Evidences of Magma Mixing Process as Triggering Mechanism.

    Science.gov (United States)

    Capra, L.; Arce, J.; Macias, J.

    2006-05-01

    Approximately 21,700 yr B.P., after a period of quiescence of 4800 yr, Nevado de Toluca volcano erupted, producing the Lower Toluca Pumice deposit. The activity generated a 24-km-high Plinian column that lasted ~11 h and dispersed 2.3 km3 (0.8 km3 dense rock equivalent) of tephra toward the NE, blanketing the Lerma basin, an area occupied today by the city of Toluca, with up to 5 cm of ash. Subsequent eruptive pulses were sub-Plinian in style, accompanied by phreatomagmatic explosions that emplaced surge deposits. Finally, the column collapsed toward the NE with the emplacement of a pumice flow deposit. The high vesicularity of the pumice from the basal Plinian layer, up to 83% by volume, indicates that exsolution was dominantly magmatic, and that pressurization of the magma chamber was probably due to a magma mixing process. Evidence for this includes the compositional range of juvenile products (from 55 to 65 wt% SiO2), as well as the presence of two types of plagioclase, one in equilibrium and the other one with disequilibrium textures and reverse zoning. This suggests input of an andesitic liquid into the dacitic magma chamber. Based on the eruptive record, the most likely future eruptive activity at Nevado de Toluca volcano will be Plinian. Although quiet for more than 3250 yr, Plinian activity could occur after a long period of quiescence, and it could represent a hazard for the entire Toluca basin, where more than one million people live today.

  16. NONLINEAR MHD WAVES IN A PROMINENCE FOOT

    Energy Technology Data Exchange (ETDEWEB)

    Ofman, L. [Catholic University of America, Washington, DC 20064 (United States); Knizhnik, K.; Kucera, T. [NASA Goddard Space Flight Center, Code 671, Greenbelt, MD 20771 (United States); Schmieder, B. [LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris-Diderot, Sorbonne Paris Cit, 5 place Jules Janssen, F-92195 Meudon (France)

    2015-11-10

    We study nonlinear waves in a prominence foot using a 2.5D MHD model motivated by recent high-resolution observations with Hinode/Solar Optical Telescope in Ca ii emission of a prominence on 2012 October 10 showing highly dynamic small-scale motions in the prominence material. Observations of Hα intensities and of Doppler shifts show similar propagating fluctuations. However, the optically thick nature of the emission lines inhibits a unique quantitative interpretation in terms of density. Nevertheless, we find evidence of nonlinear wave activity in the prominence foot by examining the relative magnitude of the fluctuation intensity (δI/I ∼ δn/n). The waves are evident as significant density fluctuations that vary with height and apparently travel upward from the chromosphere into the prominence material with quasi-periodic fluctuations with a typical period in the range of 5–11 minutes and wavelengths <2000 km. Recent Doppler shift observations show the transverse displacement of the propagating waves. The magnetic field was measured with the THEMIS instrument and was found to be 5–14 G. For the typical prominence density the corresponding fast magnetosonic speed is ∼20 km s{sup −1}, in qualitative agreement with the propagation speed of the detected waves. The 2.5D MHD numerical model is constrained with the typical parameters of the prominence waves seen in observations. Our numerical results reproduce the nonlinear fast magnetosonic waves and provide strong support for the presence of these waves in the prominence foot. We also explore gravitational MHD oscillations of the heavy prominence foot material supported by dipped magnetic field structure.

  17. NONLINEAR MHD WAVES IN A PROMINENCE FOOT

    International Nuclear Information System (INIS)

    Ofman, L.; Knizhnik, K.; Kucera, T.; Schmieder, B.

    2015-01-01

    We study nonlinear waves in a prominence foot using a 2.5D MHD model motivated by recent high-resolution observations with Hinode/Solar Optical Telescope in Ca ii emission of a prominence on 2012 October 10 showing highly dynamic small-scale motions in the prominence material. Observations of Hα intensities and of Doppler shifts show similar propagating fluctuations. However, the optically thick nature of the emission lines inhibits a unique quantitative interpretation in terms of density. Nevertheless, we find evidence of nonlinear wave activity in the prominence foot by examining the relative magnitude of the fluctuation intensity (δI/I ∼ δn/n). The waves are evident as significant density fluctuations that vary with height and apparently travel upward from the chromosphere into the prominence material with quasi-periodic fluctuations with a typical period in the range of 5–11 minutes and wavelengths <2000 km. Recent Doppler shift observations show the transverse displacement of the propagating waves. The magnetic field was measured with the THEMIS instrument and was found to be 5–14 G. For the typical prominence density the corresponding fast magnetosonic speed is ∼20 km s −1 , in qualitative agreement with the propagation speed of the detected waves. The 2.5D MHD numerical model is constrained with the typical parameters of the prominence waves seen in observations. Our numerical results reproduce the nonlinear fast magnetosonic waves and provide strong support for the presence of these waves in the prominence foot. We also explore gravitational MHD oscillations of the heavy prominence foot material supported by dipped magnetic field structure

  18. Solar Features - Prominences and Filaments

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Prominences and filaments are two manifestations of the same phenomenon. Both prominences and filaments are features formed above the chromosphere by cool dense...

  19. Erupted complex odontoma delayed eruption of permanent molar.

    Science.gov (United States)

    Ohtawa, Yumi; Ichinohe, Saori; Kimura, Eri; Hashimoto, Sadamitsu

    2013-01-01

    Odontomas, benign tumors that develop in the jaw, rarely erupt into the oral cavity. We report an erupted odontoma which delayed eruption of the first molar. The patient was a 10-year-old Japanese girl who came to our hospital due to delayed eruption of the right maxillary first molar. All the deciduous teeth had been shed. The second premolar on the right side had erupted, but not the first molar. Slight inflammation of the alveolar mucosa around the first molar had exposed a tooth-like, hard tissue. Panoramic radiography revealed a radiopaque mass indicating a lesion approximately 1 cm in diameter. The border of the image was clear, and part of the mass was situated close to the occlusal surface of the first molar. The root of the maxillary right first molar was only half-developed. A clinical diagnosis of odontoma was made. The odontoma was subsequently extracted, allowing the crown of the first molar to erupt almost 5 months later. The dental germ of the permanent tooth had been displaced by the odontoma. However, after the odontoma had been extracted, the permanent tooth was still able to erupt spontaneously, as eruptive force still remained. When the eruption of a tooth is significantly delayed, we believe that it is necessary to examine the area radiographically. If there is any radiographic evidence of a physical obstruction that might delay eruption, that obstruction should be removed before any problems can arise. Regular dental checkups at schools might improve our ability to detect evidence of delayed eruption earlier.

  20. Evidence for degassing of fresh magma during the 2004-2008 eruption of Mount St. Helens: Subtle signals from the hydrothermal system

    Science.gov (United States)

    Bergfeld, Deborah; Evans, William C.; Spicer, Kurt R.; Hunt, Andrew G.; Kelly, Peter

    2017-01-01

    Results from chemical and isotopic analyses of water and gas collected between 2002 and 2016 from sites on and around Mount St. Helens are used to assess magmatic degassing related to the 2004-2008 eruption. During 2005 the chemistry of hot springs in The Breach of Mount St. Helens showed no obvious response to the eruption, and over the next few years, changes were subtle, giving only slight indications of perturbations in the system. By 2010 however, water chemistry, temperatures, and isotope compositions (δD and δ18O) clearly indicated some inputs of volatiles and heat associated with the eruption, but the changes were such that they could be attributed to a pre-existing, gas depleted magma. An increase of ~ 1.5‰ in the δ13C values of dissolved carbon in the springs was noted in 2006 and continued through 2009, a change that was mirrored by a similar shift in δ13C-CO2 in bubble gas emissions. These changes require input of a new source of carbon to the hydrothermal system and provide clear evidence of CO2 from an undegassed body of magma. Rising trends in 3He/4He ratios in gas also accompanied the increases in δ13C. Since 2011 maximum RC/RA values are ≥ 6.4 and are distinctly higher than 5 samples collected between 1986 and 2002, and provide additional evidence for some involvement of new magma as early as 2006, and possibly earlier, given the unknown time needed for CO2 and He to traverse the system and arrive at the springs.

  1. Io - Volcanic Eruption

    Science.gov (United States)

    1979-01-01

    This photo of a volcanic eruption on Jupiter's satellite Io (dark fountain-like feature near the limb) was taken March 4, 1979, about 12 hours before Voyager 1's closest approach to Jupiter. This and the accompanying photo present the evidence for the first active volcanic eruption ever observed on another body in the solar system. This photo taken from a distance of 310,000 miles (499,000 kilometers), shows a plume-like structure rising more than 60 miles (100 kilometers) above the surface, a cloud of material being produced by an active eruption. At least four eruptions have been identified on Voyager 1 pictures and many more may yet be discovered on closer analysis. On a nearly airless body like Io, particulate material thrown out of a volcano follows a ballistic trajectory, accounting for the dome-like shape of the top of the cloud, formed as particles reach the top of their flight path and begin to fall back. Spherical expansion of outflowing gas forms an even larger cloud surrounding the dust. Several regions have been identified by the infrared instrument on Voyager 1 as being several hundred degrees Fahrenheit warmer than surrounding terrain, and correlated with the eruptions. The fact that several eruptions appear to be going on simultaneously makes Io the most active surface in the solar system and suggests to scientists that Io is undergoing continuous volcanism, revising downward the age of Io's surface once again. JPL manages and controls the Voyager Project for NASA's Office of Space Science.

  2. Recent progress in prominence seismology.

    Science.gov (United States)

    Ballester, José Luis

    2006-02-15

    Prominence seismology is a rapidly developing topic which seeks to infer the internal structure and properties of solar prominences from the study of their oscillations. An extense observational background about oscillations in quiescent solar prominences has been gathered during the last 70 years. These observations point out the existence of two different types of oscillations: flare-induced oscillations (winking filaments) which affect the whole prominence and are of large amplitude and small amplitude oscillations which seem to be of local nature. From the theoretical point of view, few models have been set up to explain the phenomenon of winking filaments while, on the contrary, for small amplitude oscillations a large number of models trying to explain the observed features have been proposed. Here, recent theoretical and observational developments on both types of oscillations are reviewed, and suggestions about future research topics which should provide us with a more in-depth knowledge of solar prominences are made.

  3. Automated detection of solar eruptions

    Directory of Open Access Journals (Sweden)

    Hurlburt N.

    2015-01-01

    Full Text Available Observation of the solar atmosphere reveals a wide range of motions, from small scale jets and spicules to global-scale coronal mass ejections (CMEs. Identifying and characterizing these motions are essential to advancing our understanding of the drivers of space weather. Both automated and visual identifications are currently used in identifying Coronal Mass Ejections. To date, eruptions near the solar surface, which may be precursors to CMEs, have been identified primarily by visual inspection. Here we report on Eruption Patrol (EP: a software module that is designed to automatically identify eruptions from data collected by the Atmospheric Imaging Assembly on the Solar Dynamics Observatory (SDO/AIA. We describe the method underlying the module and compare its results to previous identifications found in the Heliophysics Event Knowledgebase. EP identifies eruptions events that are consistent with those found by human annotations, but in a significantly more consistent and quantitative manner. Eruptions are found to be distributed within 15 Mm of the solar surface. They possess peak speeds ranging from 4 to 100 km/s and display a power-law probability distribution over that range. These characteristics are consistent with previous observations of prominences.

  4. Glacier melting during lava dome growth at Nevado de Toluca volcano (Mexico): Evidences of a major threat before main eruptive phases at ice-caped volcanoes

    Science.gov (United States)

    Capra, L.; Roverato, M.; Groppelli, G.; Caballero, L.; Sulpizio, R.; Norini, G.

    2015-03-01

    Nevado de Toluca volcano is one of the largest stratovolcanoes in the Trans-Mexican Volcanic Belt. During Late Pleistocene its activity was characterized by large dome growth and subsequent collapse emplacing large block and ash flow deposits, intercalated by Plinian eruptions. Morphological and paleoclimate studies at Nevado de Toluca and the surrounding area evidenced that the volcano was affected by extensive glaciation during Late Pleistocene and Holocene. During the older recognized glacial period (27-60 ka, MIS 3), the glacier was disturbed by the intense magmatic and hydrothermal activity related to two dome extrusion episodes (at 37 ka and 28 ka). Glacier reconstruction indicates maximum ice thickness of 90 m along main valleys, as at the Cano ravines, the major glacial valley on the northern slope of the volcano. Along this ravine, both 37 and 28 ka block-and-ash deposits are exposed, and they directly overlay a fluviatile sequence, up to 40 m-thick, which 14C ages clearly indicate that their emplacement occurred just before the dome collapsed. These evidences point to a clear interaction between the growing dome and its hydrothermal system with the glacier. During dome growth, a large amount of melting water was released along major glacial valleys forming thick fluvioglacial sequences that were subsequently covered by the block-and-ash flow deposits generated by the collapse of the growing dome. Even though this scenario is no longer possible at the Nevado de Toluca volcano, the data presented here indicate that special attention should be paid to the possible inundation areas from fluviatile/lahar activity prior to the main magmatic eruption at ice-capped volcanoes.

  5. Greenhouse effect in quiescent prominences

    Science.gov (United States)

    Ryutova, M.; Berger, T. E.; Title, A. M.

    2010-12-01

    Quiescent prominences, by definition, are huge ``clouds'' of cool, dense plasma overlying rarefied hot corona and supported by a complex magnetic field anchored in the photosphere along the magnetic polarity inversion line. One of the most prominent features in their dynamics is formation, growth and collapse of bubble/cavities filled by coronal plasma and emerging, often repeatedly, under a prominence body. As such, prominence/corona interface itself is subject of fundamental plasma instabilities, which include development of a regular series of plumes and spikes typical to the Rayleigh-Taylor instability, the Kelvin-Helmholtz instability, often followed by a sudden collimated mass upflow, which, in nonlinear stage having an explosive character may be responsible for CMEs. These were only recently studied in detail with high cadence, high resolution data obtained from the Hinode satellite. Even more surprises are brought by the SDO/AIA instrument showing the Sun's atmosphere in 12 visible and EUV wavelengths. AIA multi-wavelength images in a temperature range from 105 ~K to 2 × 106 ~K combined with the Hinode/SOT data show that plasma inside the prominence cavity, being as expected, at coronal temperatures, in fact exceeds the temperature of the ambient corona. We suggest that an energetically open highly dynamic processes releasing energy at the prominence/cavity interface accompanied by the ``radiative exchange'', may cause additional increase of temperature and/or density inside cavity. Given pervasive character of prominences, future studies will allow us to perform quantitative and statistical analysis, and reveal relations between the size of cavity, its temperature, and magnetic properties.

  6. CRITICAL HEIGHT FOR THE DESTABILIZATION OF SOLAR PROMINENCES: STATISTICAL RESULTS FROM STEREO OBSERVATIONS

    International Nuclear Information System (INIS)

    Liu Kai; Wang Yuming; Wang Shui; Shen Chenglong

    2012-01-01

    At which height is a prominence inclined to be unstable, or where is the most probable critical height for the prominence destabilization? This question was statistically studied based on 362 solar limb prominences well recognized by Solar Limb Prominence Catcher and Tracker from 2007 April to the end of 2009. We found that there are about 71% disrupted prominences (DPs), among which about 42% of them did not erupt successfully and about 89% of them experienced a sudden destabilization process. After a comprehensive analysis of the DPs, we discovered the following: (1) Most DPs become unstable at a height of 0.06-0.14 R ☉ from the solar surface, and there are two most probable critical heights at which a prominence is very likely to become unstable, the first one is 0.13 R ☉ and the second one is 0.19 R ☉ . (2) An upper limit for the erupting velocity of eruptive prominences (EPs) exists, which decreases following a power law with increasing height and mass; accordingly, the kinetic energy of EPs has an upper limit too, which decreases as the critical height increases. (3) Stable prominences are generally longer and heavier than DPs, and not higher than 0.4 R ☉ . (4) About 62% of the EPs were associated with coronal mass ejections (CMEs); but there is no difference in apparent properties between EPs associated with CMEs and those that are not.

  7. Source of the great A.D. 1257 mystery eruption unveiled, Samalas volcano, Rinjani Volcanic Complex, Indonesia.

    Science.gov (United States)

    Lavigne, Franck; Degeai, Jean-Philippe; Komorowski, Jean-Christophe; Guillet, Sébastien; Robert, Vincent; Lahitte, Pierre; Oppenheimer, Clive; Stoffel, Markus; Vidal, Céline M; Surono; Pratomo, Indyo; Wassmer, Patrick; Hajdas, Irka; Hadmoko, Danang Sri; de Belizal, Edouard

    2013-10-15

    Polar ice core records attest to a colossal volcanic eruption that took place ca. A.D. 1257 or 1258, most probably in the tropics. Estimates based on sulfate deposition in these records suggest that it yielded the largest volcanic sulfur release to the stratosphere of the past 7,000 y. Tree rings, medieval chronicles, and computational models corroborate the expected worldwide atmospheric and climatic effects of this eruption. However, until now there has been no convincing candidate for the mid-13th century "mystery eruption." Drawing upon compelling evidence from stratigraphic and geomorphic data, physical volcanology, radiocarbon dating, tephra geochemistry, and chronicles, we argue the source of this long-sought eruption is the Samalas volcano, adjacent to Mount Rinjani on Lombok Island, Indonesia. At least 40 km(3) (dense-rock equivalent) of tephra were deposited and the eruption column reached an altitude of up to 43 km. Three principal pumice fallout deposits mantle the region and thick pyroclastic flow deposits are found at the coast, 25 km from source. With an estimated magnitude of 7, this event ranks among the largest Holocene explosive eruptions. Radiocarbon dates on charcoal are consistent with a mid-13th century eruption. In addition, glass geochemistry of the associated pumice deposits matches that of shards found in both Arctic and Antarctic ice cores, providing compelling evidence to link the prominent A.D. 1258/1259 ice core sulfate spike to Samalas. We further constrain the timing of the mystery eruption based on tephra dispersal and historical records, suggesting it occurred between May and October A.D. 1257.

  8. Neutral Atom Diffusion in a Partially Ionized Prominence Plasma

    Science.gov (United States)

    Gilbert, Holly

    2010-01-01

    The support of solar prominences is normally described in terms of a magnetic force on the prominence plasma that balances the solar gravitational force. Because the prominence plasma is only partially ionized. it is necessary to consider in addition the support of the neutral component of the prominence plasma. This support is accomplished through a frictional interaction between the neutral and ionized components of the plasma, and its efficacy depends strongly on the degree of ionization of the plasma. More specifically, the frictional force is proportional to the relative flow of neutral and ion species, and for a sufficiently weakly ionized plasma, this flow must be relatively large to produce a frictional force that balances gravity. A large relative flow, of course, implies significant draining of neutral particles from the prominence. We evaluate the importance of this draining effect for a hydrogen-helium plasma, and consider the observational evidence for cross-field diffusion of neutral prominence material,

  9. Variations in eruption style during the 1931 A.D. eruption of Aniakchak volcano, Alaska

    Science.gov (United States)

    Nicholson, Robert S.; Gardner, James E.; Neal, Christina A.

    2011-01-01

    The 1931 A.D. eruption of Aniakchak volcano, Alaska, progressed from subplinian to effusive eruptive style and from trachydacite to basaltic andesite composition from multiple vent locations. Eyewitness accounts and new studies of deposit stratigraphy provide a combined narrative of eruptive events. Additional field, compositional, grain size, componentry, density, and grain morphology data document the influences on changing eruptive style as the eruption progressed. The eruption began on 1 May 1931 A.D. when a large subplinian eruption column produced vesicular juvenile-rich tephra. Subsequent activity was more intermittent, as magma interacted with groundwater and phreatomagmatic ash and lithic-rich tephra was dispersed up to 600 km downwind. Final erupted products were more mafic in composition and the eruption became more strombolian in style. Stratigraphic evidence suggests that two trachydacitic lava flows were erupted from separate but adjacent vents before the phreatomagmatic phase concluded and that basaltic andesite lava from a third vent began to effuse near the end of explosive activity. The estimated total bulk volume of the eruption is 0.9 km3, which corresponds to approximately 0.3 km3 of magma. Eruption style changes are interpreted as follows: (1) a decrease in magma supply rate caused the change from subplinian to phreatomagmatic eruption; (2) a subsequent change in magma composition caused the transition from phreatomagmatic to strombolian eruption style. Additionally, the explosion and effusion of a similar magma composition from three separate vents indicates how the pre-existing caldera structure controlled the pathway of shallow magma ascent, thus influencing eruption style.

  10. The most prominent safety guarantees

    International Nuclear Information System (INIS)

    Lucenet, G.

    1978-01-01

    The Creys-Malville Nuclear Centre has been designed using the safety analysis implemented since the beginning of the developments of breeder reactors in France and the Super Phenix follows almost the same safety regulations as its predecessor the Phenix reactor. These regulations are based on: 'Recommendations for the safety standards of the Super Phenix' drawn up by the French Safety Authorities in July 1973. The prominent points are summarised. (C.F.)

  11. Post-eruptive alteration of silicic ignimbrites and lavas, Gran Canaria, Canary Islands - Strontium, neodymium, lead, and oxygen isotopic evidence

    Science.gov (United States)

    Cousens, Brian L.; Spera, Frank J.; Dobson, Patrick F.

    1993-01-01

    The isotopic composition of lavas from oceanic islands provides important information about the composition and evolution of the earth's mantle. Isotopic analyses of Miocene comenditic, pantelleritic, and trachyphonolitic ignimbrites and lavas from the Canary islands were performed. Results provide evidence for posteruptive mobility of Rb and Sr during low temperature postemplacement interaction with circulating ground water. Calculated Sr isotope ratios define a magmatic trend in the stratigraph section. 87Sr/86Sr ratios in hydrated vitrophyte and devitrified matrix separates indicate significant posteruptive interaction with meteoric water starting soon after deposition. This process extends patchily through the entire pyroclastic flow and may be ongoing. 87Sr/86Sr ratios determined by whole rock analysis of silicic rocks from oceanic islands are suspect and should not be incorporated into mantle tracer studies. Anorthoclase phenocrysts are resistant to these processes and may produce useful data.

  12. The 1994-2001 eruptive period at Rabaul, Papua New Guinea: Petrological and geochemical evidence for basalt injections into a shallow dacite magma reservoir, and significant SO2 flux

    Science.gov (United States)

    Patia, H.; Eggins, S. M.; Arculus, R. J.; McKee, C. O.; Johnson, R. W.; Bradney, A.

    2017-10-01

    The eruptions that began at Rabaul Caldera on 19 September 1994 had two focal points, the vents Tavurvur and Vulcan, located 6 km apart on opposing sides of the caldera. Vulcan eruptives define a tight cluster of dacite compositions, whereas Tavurvur eruptives span an array from equivalent dacite compositions to mafic andesites. The eruption of geochemically and mineralogically identical dacites from both vents indicates sourcing from the same magma reservoir. This, together with previously reported H2O-CO2 volatile contents of dacite melt inclusions, a caldera-wide seismic low-velocity zone, and a seismically active caldera ring fault structure are consistent with the presence at 3-6 km depth of an extensive, tabular dacitic magma body having volume of about 15-150 km3. The Tavurvur andesites form a linear compositional array and have strongly bimodal phenocryst assemblages that reflect dacite hybridisation with a mafic basalt. The moderately large volume SO2 flux documented in the Tavurvur volcanic plume (and negligible SO2 flux in the Vulcan plume) combined with high dissolved S contents of basaltic melt inclusions trapped in olivine of Tavurvur eruptives, indicate that the amount of degassed basaltic magma was 0.1 km3 and suggest that the injection of this magma was confined to the Tavurvur-side (eastern to northeastern sector) of the caldera. Circumstantial evidence suggests that the eruption was triggered and evolved in response to a series of basaltic magma injections that may have commenced in 1971 and continued up until at least the start of the 1994 eruptions. The presence of zoned plagioclase phenocrysts reflecting older basalt-dacite interaction events (i.e. anorthite cores overgrown with thick andesine rims), evaluation of limited available data for the products of previous eruptions in 1878 and 1937-1943, and the episodic occurrence of major intra-caldera seismo-deformational events indicates that the shallow magma system at Rabaul Caldera is

  13. Dental eruption in afrotherian mammals

    Directory of Open Access Journals (Sweden)

    Lehmann Thomas

    2008-03-01

    Full Text Available Abstract Background Afrotheria comprises a newly recognized clade of mammals with strong molecular evidence for its monophyly. In contrast, morphological data uniting its diverse constituents, including elephants, sea cows, hyraxes, aardvarks, sengis, tenrecs and golden moles, have been difficult to identify. Here, we suggest relatively late eruption of the permanent dentition as a shared characteristic of afrotherian mammals. This characteristic and other features (such as vertebral anomalies and testicondy recall the phenotype of a human genetic pathology (cleidocranial dysplasia, correlations with which have not been explored previously in the context of character evolution within the recently established phylogeny of living mammalian clades. Results Although data on the absolute timing of eruption in sengis, golden moles and tenrecs are still unknown, craniometric comparisons for ontogenetic series of these taxa show that considerable skull growth takes place prior to the complete eruption of the permanent cheek teeth. Specimens showing less than half (sengis, golden moles or two-thirds (tenrecs, hyraxes of their permanent cheek teeth reach or exceed the median jaw length of conspecifics with a complete dentition. With few exceptions, afrotherians are closer to median adult jaw length with fewer erupted, permanent cheek teeth than comparable stages of non-afrotherians. Manatees (but not dugongs, elephants and hyraxes with known age data show eruption of permanent teeth late in ontogeny relative to other mammals. While the occurrence of delayed eruption, vertebral anomalies and other potential afrotherian synapomorphies resemble some symptoms of a human genetic pathology, these characteristics do not appear to covary significantly among mammalian clades. Conclusion Morphological characteristics shared by such physically disparate animals such as elephants and golden moles are not easy to recognize, but are now known to include late eruption

  14. Perceived prominence and scale types

    DEFF Research Database (Denmark)

    Tøndering, John; Jensen, Christian

    2005-01-01

    Three different scales which have been used to measure perceived prominence are evaluated in a perceptual experiment. Average scores of raters using a multi-level (31-point) scale, a simple binary (2-point) scale and an intermediate 4-point scale are almost identical. The potentially finer...... gradation possible with the multilevel scale(s) is compensated for by having multiple listeners, which is a also a requirement for obtaining reliable data. In other words, a high number of levels is neither a sufficient nor a necessary requirement. Overall the best results were obtained using the 4-point...... scale, and there seems to be little justification for using a 31-point scale....

  15. H-alpha Proxies for EIT Crinkles: Further Evidence for Pre-Flare "Breakout"-Type Activity in an Ejective Solar Eruption

    Science.gov (United States)

    Sterling, Alphonse C.; Moore, R. L.; Qiu, J.; Wang, H.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    We present Halpha observations from Big Bear Solar Observatory of an eruptive flare in NOAA AR 8210, occurring near 22:30 UT on 1998 May 1. Previously, using the EUV Imaging Telescope (EIT) on the SOHO spacecraft, we found that a pattern of transient, localized brightenings, which we call "EIT crinkles," appears in the neighborhood of the eruption near the time of flare onset. These EIT crinkles occur at a location in the active region well separated from the sheared core magnetic fields, which is where the most intense features of the eruption are concentrated. We also previously found that high-cadence images from the Soft X-ray Telescope (SXT) on Yohkoh indicate that soft X-ray intensity enhancements in the core begin after the start of the EIT crinkles. With the Halpha data, we find remote flare brightening counterparts to the EIT crinkles. Lightcurves as functions of time of various areas of the active region show that several of the remote flare brightenings undergo intensity increases prior to onset of principle brightenings in the core region, consistent with our earlier findings from EIT and SXT data. These timing relationships are consistent with the eruption onset mechanism known as the breakout model, introduced by Antiochos and colleagues, which proposes that eruptions begin with reconnection at a magnetic null high above the core region. Our observations are also consistent with other proposed mechanisms which do not involve early reconnection in the core region. As a corollary, our observations are not consistent with the so-called tether cutting models, which say that the eruption begins with reconnection in the core. The Halpha data further show that a filament in the core region becomes activated near the time of EIT crinkle onset, but little if any of the filament actually erupts, despite the presence of a halo Coronal Mass Ejection (CME) associated with this event.

  16. Tooth Eruption without Roots

    OpenAIRE

    Wang, X.-P.

    2013-01-01

    Root development and tooth eruption are very important topics in dentistry. However, they remain among the less-studied and -understood subjects. Root development accompanies rapid tooth eruption, but roots are required for the movement of teeth into the oral cavity. It has been shown that the dental follicle and bone remodeling are essential for tooth eruption. So far, only limited genes have been associated with root formation and tooth eruption. This may be due to the diffic...

  17. An erupted compound odontoma.

    Science.gov (United States)

    Gupta, Anil; Vij, Hitesh; Vij, Ruchieka; Malhotra, Ritika

    2014-04-12

    Odontomas are familiar entities but their eruption into the oral cavity is an extraordinary occurrence, which may be associated with pain, infection, malocclusion, etc. Not many cases of erupted odontomas have been reported in the literature. This paper puts forth a case of erupting odontoma in an attempt to add to the list of reported cases of this unique pathology.

  18. Volatile-induced magma differentiation in the plumbing system of Mt. Etna volcano (Italy): evidence from glass in tephra of the 2001 eruption

    Science.gov (United States)

    Ferlito, Carmelo; Viccaro, Marco; Cristofolini, Renato

    2008-02-01

    Mount Etna volcano was shaken during the summer 2001 by one of the most singular eruptive episodes of the last centuries. For about 3 weeks, several eruptive fractures developed, emitting lava flows and tephra that significantly modified the landscape of the southern flank of the volcano. This event stimulated the attention of the scientific community especially for the simultaneous emission of petrologically distinct magmas, recognized as coming from different segments of the plumbing system. A stratigraphically controlled sampling of tephra layers was performed at the most active vents of the eruption, in particular at the 2,100 m (CAL) and at the 2,550 m (LAG) scoria cones. Detailed scanning electron microscope and energy dispersive x-ray spectrometer (SEM-EDS) analyses performed on glasses found in tephra and comparison with lava whole rock compositions indicate an anomalous increase in Ti, Fe, P, and particularly of K and Cl in the upper layers of the LAG sequence. Mass balance and thermodynamic calculations have shown that this enrichment cannot be accounted for by “classical” differentiation processes, such as crystal fractionation and magma mixing. The analysis of petrological features of the magmas involved in the event, integrated with the volcanological evolution, has evidenced the role played by volatiles in controlling the magmatic evolution within the crustal portion of the plumbing system. Volatiles, constituted of H2O, CO2, and Cl-complexes, originated from a deeply seated magma body (DBM). Their upward migration occurred through a fracture network possibly developed by the seismic swarms during the period preceding the event. In the upper portion of the plumbing system, a shallower residing magma body (ABT) had chemical and physical conditions to receive migrating volatiles, which hence dissolved the mobilized elements producing the observed selective enrichment. This volatile-induced differentiation involved exclusively the lowest erupted

  19. Are Giant Tornadoes the Legs of Solar Prominences?

    Science.gov (United States)

    Wedemeyer, Sven; Scullion, Eamon; Rouppe van der Voort, Luc; Bosnjak, Antonija; Antolin, Patrick

    2013-09-01

    Observations in the 171 Å channel of the Atmospheric Imaging Assembly of the space-borne Solar Dynamics Observatory show tornado-like features in the atmosphere of the Sun. These giant tornadoes appear as dark, elongated, and apparently rotating structures in front of a brighter background. This phenomenon is thought to be produced by rotating magnetic field structures that extend throughout the atmosphere. We characterize giant tornadoes through a statistical analysis of properties such as spatial distribution, lifetimes, and sizes. A total number of 201 giant tornadoes are detected in a period of 25 days, suggesting that, on average, about 30 events are present across the whole Sun at a time close to solar maximum. Most tornadoes appear in groups and seem to form the legs of prominences, thus serving as plasma sources/sinks. Additional Hα observations with the Swedish 1 m Solar Telescope imply that giant tornadoes rotate as a structure, although they clearly exhibit a thread-like structure. We observe tornado groups that grow prior to the eruption of the connected prominence. The rotation of the tornadoes may progressively twist the magnetic structure of the prominence until it becomes unstable and erupts. Finally, we investigate the potential relation of giant tornadoes to other phenomena, which may also be produced by rotating magnetic field structures. A comparison to cyclones, magnetic tornadoes, and spicules implies that such events are more abundant and short-lived the smaller they are. This comparison might help to construct a power law for the effective atmospheric heating contribution as a function of spatial scale.

  20. ARE GIANT TORNADOES THE LEGS OF SOLAR PROMINENCES?

    International Nuclear Information System (INIS)

    Wedemeyer, Sven; Scullion, Eamon; Rouppe van der Voort, Luc; Bosnjak, Antonija; Antolin, Patrick

    2013-01-01

    Observations in the 171 Å channel of the Atmospheric Imaging Assembly of the space-borne Solar Dynamics Observatory show tornado-like features in the atmosphere of the Sun. These giant tornadoes appear as dark, elongated, and apparently rotating structures in front of a brighter background. This phenomenon is thought to be produced by rotating magnetic field structures that extend throughout the atmosphere. We characterize giant tornadoes through a statistical analysis of properties such as spatial distribution, lifetimes, and sizes. A total number of 201 giant tornadoes are detected in a period of 25 days, suggesting that, on average, about 30 events are present across the whole Sun at a time close to solar maximum. Most tornadoes appear in groups and seem to form the legs of prominences, thus serving as plasma sources/sinks. Additional Hα observations with the Swedish 1 m Solar Telescope imply that giant tornadoes rotate as a structure, although they clearly exhibit a thread-like structure. We observe tornado groups that grow prior to the eruption of the connected prominence. The rotation of the tornadoes may progressively twist the magnetic structure of the prominence until it becomes unstable and erupts. Finally, we investigate the potential relation of giant tornadoes to other phenomena, which may also be produced by rotating magnetic field structures. A comparison to cyclones, magnetic tornadoes, and spicules implies that such events are more abundant and short-lived the smaller they are. This comparison might help to construct a power law for the effective atmospheric heating contribution as a function of spatial scale

  1. Human responses to the 1906 eruption of Vesuvius, southern Italy

    Science.gov (United States)

    Chester, David; Duncan, Angus; Kilburn, Christopher; Sangster, Heather; Solana, Carmen

    2015-04-01

    Cultural and political contexts are important in determining the ways in which communities respond to volcanic eruptions. Understanding the manner in which communities and the State apparatus have coped with historic eruptions can provide insights into how responses have influenced vulnerability and resilience. The 1906 eruption of Vesuvius is well suited for such a study as it was one of the first major eruptions in which there was a significant element of State control, and this worked alongside more traditional pre-industrial responses. This eruption was extensively reported in the regional, national and international press and in archives which include still photography. One feature is the rich archive of material published in English language newspapers of record which are analysed fully in the paper for the first time. Many of these data sources are now accessible on-line. The eruption started on April 4th with mild explosive activity and the eruption of lava from 5th to 7th April. On the night of the 7th/8th, activity intensified when a vigorous lava fountain inclined obliquely to the north east, deposited a thick layer of tephra on the towns of Ottaviano and San Giuseppe. This led to roof collapse and a large number of fatalities. There was increased lava emission and a flow progressed south through the outskirts of Boscotrecase cutting the Circumvesuviana railway line and almost reaching Torre Annunziata. Following April 8th the eruption declined and ended on April 21st. In the initial responses to the eruption pre-industrial features were prominent, with the local communities showing social cohesion, self-reliance and little panic. A more negative aspect was the traditional religious response that involved the use of liturgies of divine appeasement and which included the use of saintly relics and images. There is interesting evidence, however, that this coping strategy was driven by the populace rather than by the clergy. The inhabitants of San Giuseppe

  2. Tooth eruption without roots.

    Science.gov (United States)

    Wang, X-P

    2013-03-01

    Root development and tooth eruption are very important topics in dentistry. However, they remain among the less-studied and -understood subjects. Root development accompanies rapid tooth eruption, but roots are required for the movement of teeth into the oral cavity. It has been shown that the dental follicle and bone remodeling are essential for tooth eruption. So far, only limited genes have been associated with root formation and tooth eruption. This may be due to the difficulties in studying late stages of tooth development and tooth movement and the lack of good model systems. Transgenic mice with eruption problems and short or no roots can be used as a powerful model for further deciphering of the cellular, molecular, and genetic mechanisms underlying root formation and tooth eruption. Better understanding of these processes can provide hints on delivering more efficient dental therapies in the future.

  3. An Eruption on Io

    Science.gov (United States)

    2007-01-01

    The first images returned to Earth by New Horizons during its close encounter with Jupiter feature the Galilean moon Io, snapped with the Long Range Reconnaissance Imager (LORRI) at 0840 UTC on February 26, while the moon was 2.5 million miles (4 million kilometers) from the spacecraft. Io is intensely heated by its tidal interaction with Jupiter and is thus extremely volcanically active. That activity is evident in these images, which reveal an enormous dust plume, more than 150 miles high, erupting from the volcano Tvashtar. The plume appears as an umbrella-shaped feature of the edge of Io's disk in the 11 o'clock position in the right image, which is a long-exposure (20-millisecond) frame designed specifically to look for plumes like this. The bright spots at 2 o'clock are high mountains catching the setting sun; beyond them the night side of Io can be seen, faintly illuminated by light reflected from Jupiter itself. The left image is a shorter exposure -- 3 milliseconds -- designed to look at surface features. In this frame, the Tvashtar volcano shows as a dark spot, also at 11 o'clock, surrounded by a large dark ring, where an area larger than Texas has been covered by fallout from the giant eruption. This is the clearest view yet of a plume from Tvashtar, one of Io's most active volcanoes. Ground-based telescopes and the Galileo Jupiter orbiter first spotted volcanic heat radiation from Tvashtar in November 1999, and the Cassini spacecraft saw a large plume when it flew past Jupiter in December 2000. The Keck telescope in Hawaii picked up renewed heat radiation from Tvashtar in spring 2006, and just two weeks ago the Hubble Space Telescope saw the Tvashtar plume in ultraviolet images designed to support the New Horizons flyby. Most of those images will be stored onboard the spacecraft for downlink to Earth in March and April.

  4. Linking rapid magma reservoir assembly and eruption trigger mechanisms at evolved Yellowstone-type supervolcanoes

    Science.gov (United States)

    Wotzlaw, J.F.; Bindeman, I.N.; Watts, Kathryn E.; Schmitt, A.K.; Caricchi, L.; Schaltegger, U.

    2014-01-01

    The geological record contains evidence of volcanic eruptions that were as much as two orders of magnitude larger than the most voluminous eruption experienced by modern civilizations, the A.D. 1815 Tambora (Indonesia) eruption. Perhaps nowhere on Earth are deposits of such supereruptions more prominent than in the Snake River Plain–Yellowstone Plateau (SRP-YP) volcanic province (northwest United States). While magmatic activity at Yellowstone is still ongoing, the Heise volcanic field in eastern Idaho represents the youngest complete caldera cycle in the SRP-YP, and thus is particularly instructive for current and future volcanic activity at Yellowstone. The Heise caldera cycle culminated 4.5 Ma ago in the eruption of the ∼1800 km3 Kilgore Tuff. Accessory zircons in the Kilgore Tuff display significant intercrystalline and intracrystalline oxygen isotopic heterogeneity, and the vast majority are 18O depleted. This suggests that zircons crystallized from isotopically distinct magma batches that were generated by remelting of subcaldera silicic rocks previously altered by low-δ18O meteoric-hydrothermal fluids. Prior to eruption these magma batches were assembled and homogenized into a single voluminous reservoir. U-Pb geochronology of isotopically diverse zircons using chemical abrasion–isotope dilution–thermal ionization mass spectrometry yielded indistinguishable crystallization ages with a weighted mean 206Pb/238U date of 4.4876 ± 0.0023 Ma (MSWD = 1.5; n = 24). These zircon crystallization ages are also indistinguishable from the sanidine 40Ar/39Ar dates, and thus zircons crystallized close to eruption. This requires that shallow crustal melting, assembly of isolated batches into a supervolcanic magma reservoir, homogenization, and eruption occurred extremely rapidly, within the resolution of our geochronology (103–104 yr). The crystal-scale image of the reservoir configuration, with several isolated magma batches, is very similar to the

  5. New zircon (U-Th)/He and U/Pb eruption age for the Rockland tephra, western USA

    Science.gov (United States)

    Coble, Matthew A.; Burgess, Seth; Klemetti, Erik W.

    2017-01-01

    Eruption ages of a number of prominent Quaternary volcanic deposits remain inaccurately and/or imprecisely constrained, despite their importance as regional stratigraphic markers in paleo-environment reconstruction and as evidence of climate-altering eruptions. Accurately dating volcanic deposits presents challenging analytical considerations, including poor radiogenic yield, scarcity of datable minerals, and contamination of crystal populations by magma, eruption, and transport processes. One prominent example is the Rockland tephra, which erupted from the Lassen Volcanic Center in the southern Cascade arc. Despite a range in published eruption ages from 0.40 to 0.63 Ma, the Rockland tephra is extensively used as a marker bed across the western United States. To more accurately and precisely constrain the age of the Rockland tephra-producing eruption, we report U/Pb crystallization dates from the outermost ∼2 μm of zircon crystal faces (surfaces) using secondary ion mass spectrometry (SIMS). Our new weighted mean 238U/206Pb age for Rockland tephra zircon surfaces is 0.598 ± 0.013 Ma (2σ) and MSWD = 1.11 (mean square weighted deviation). As an independent test of the accuracy of this age, we obtained new (U-Th)/He dates from individual zircon grains from the Rockland tephra, which yielded a weighted mean age of 0.599 ± 0.012 Ma (2σ, MSWD = 5.13). We also obtained a (U-Th)/He age of 0.628 ± 0.014 Ma (MSWD = 1.19) for the Lava Creek Tuff member B, which was analyzed as a secondary standard to test the accuracy of the (U-Th)/He technique for Quaternary tephras, and to evaluate assumptions made in the model-age calculation. Concordance of new U/Pb and (U-Th)/He zircon ages reinforces the accuracy of our preferred Rockland tephra eruption age, and confirms that zircon surface dates sample zircon growth up to the time of eruption. We demonstrate the broad applicability of coupled U/Pb zircon-surface and single-grain zircon (U-Th)/He geochronology to

  6. New zircon (U-Th)/He and U/Pb eruption age for the Rockland tephra, western USA

    Science.gov (United States)

    Coble, Matthew A.; Burgess, Seth D.; Klemetti, Erik W.

    2017-09-01

    Eruption ages of a number of prominent Quaternary volcanic deposits remain inaccurately and/or imprecisely constrained, despite their importance as regional stratigraphic markers in paleo-environment reconstruction and as evidence of climate-altering eruptions. Accurately dating volcanic deposits presents challenging analytical considerations, including poor radiogenic yield, scarcity of datable minerals, and contamination of crystal populations by magma, eruption, and transport processes. One prominent example is the Rockland tephra, which erupted from the Lassen Volcanic Center in the southern Cascade arc. Despite a range in published eruption ages from 0.40 to 0.63 Ma, the Rockland tephra is extensively used as a marker bed across the western United States. To more accurately and precisely constrain the age of the Rockland tephra-producing eruption, we report U/Pb crystallization dates from the outermost ∼2 μm of zircon crystal faces (surfaces) using secondary ion mass spectrometry (SIMS). Our new weighted mean 238U/206Pb age for Rockland tephra zircon surfaces is 0.598 ± 0.013 Ma (2σ) and MSWD = 1.11 (mean square weighted deviation). As an independent test of the accuracy of this age, we obtained new (U-Th)/He dates from individual zircon grains from the Rockland tephra, which yielded a weighted mean age of 0.599 ± 0.012 Ma (2σ, MSWD = 5.13). We also obtained a (U-Th)/He age of 0.628 ± 0.014 Ma (MSWD = 1.19) for the Lava Creek Tuff member B, which was analyzed as a secondary standard to test the accuracy of the (U-Th)/He technique for Quaternary tephras, and to evaluate assumptions made in the model-age calculation. Concordance of new U/Pb and (U-Th)/He zircon ages reinforces the accuracy of our preferred Rockland tephra eruption age, and confirms that zircon surface dates sample zircon growth up to the time of eruption. We demonstrate the broad applicability of coupled U/Pb zircon-surface and single-grain zircon (U-Th)/He geochronology to accurate

  7. Apparent Solar Tornado-Like Prominences

    Science.gov (United States)

    Panasenco, Olga; Martin, Sara F.; Velli, Marco

    2014-02-01

    Recent high-resolution observations from the Solar Dynamics Observatory (SDO) have reawakened interest in the old and fascinating phenomenon of solar tornado-like prominences. This class of prominences was first introduced by Pettit ( Astrophys. J. 76, 9, 1932), who studied them over many years. Observations of tornado prominences similar to the ones seen by SDO had already been documented by Secchi ( Le Soleil, 1877). High-resolution and high-cadence multiwavelength data obtained by SDO reveal that the tornado-like appearance of these prominences is mainly an illusion due to projection effects. We discuss two different cases where prominences on the limb might appear to have a tornado-like behavior. One case of apparent vortical motions in prominence spines and barbs arises from the (mostly) 2D counterstreaming plasma motion along the prominence spine and barbs together with oscillations along individual threads. The other case of apparent rotational motion is observed in a prominence cavity and results from the 3D plasma motion along the writhed magnetic fields inside and along the prominence cavity as seen projected on the limb. Thus, the "tornado" impression results either from counterstreaming and oscillations or from the projection on the plane of the sky of plasma motion along magnetic-field lines, rather than from a true vortical motion around an (apparent) vertical or horizontal axis. We discuss the link between tornado-like prominences, filament barbs, and photospheric vortices at their base.

  8. Mechanism of human tooth eruption

    DEFF Research Database (Denmark)

    Kjær, Inger

    2014-01-01

    Human eruption is a unique developmental process in the organism. The aetiology or the mechanism behind eruption has never been fully understood and the scientific literature in the field is extremely sparse. Human and animal tissues provide different possibilities for eruption analyses, briefly...... discussed in the introduction. Human studies, mainly clinical and radiological, have focused on normal eruption and gender differences. Why a tooth begins eruption and what enables it to move eruptively and later to end these eruptive movements is not known. Pathological eruption courses contribute......, and the ability of the periodontal ligament to adapt to eruptive movements. Animal studies and studies on normal and pathological eruption in humans can support and explain different aspects in the new theory. The eruption mechanism still needs elucidation and the paper recommends that future research on eruption...

  9. Volatile Release and Eruption Dynamics of a Basaltic Plinian Eruption From Masaya Caldera, Nicaragua

    Science.gov (United States)

    Wehrmann, H.; Freundt, A.; Kutterolf, S.; Schmincke, H.; Strauch, W.

    2003-12-01

    Our project is part of SFB 574 "Volatiles and Fluids in subduction zones", and focusses on degassing dynamics of highly-explosive arc volcanoes. Masaya Caldera in west-central Nicaragua is part of the Central American volcanic arc at the convergent boundary of the Cocos and Carribean plates. A basaltic plinian eruption of VEI 6 occurred at Masaya Caldera in the Late-Pleistocene, depositing a widespread fan of scoria lapilli, named Fontana Tephra. We have constrained parameters of the Fontana eruption by extensive isopach and isopleth mapping. Total erupted tephra volume is >0.83 km3 (about 1012 kg DRE). The eruption columns reached 30 to 35 km height at an average discharge rate of 1.3*108 kg/s. This violent eruption was not continuous but proceeded in distinct pulses evident by the well-bedded deposit. An initial sequence of numerous highly explosive but short pulses formed a well-bedded layer of very highly vesicular, hawaiian-type lapilli, possibly representing a gas-enriched top zone of the magma reservoir. The following series of longer-duration plinian events, interupted by weak phases of ash emission, formed beds of highly vesicular scoria lapilli. The eruption ceased with abundant short-lived pulses of lower-energy subplinian activity. We estimate volatile emissions during the eruption from the differences in volatile concentration between matrix glass and glass inclusions in minerals, considered to represent degassed and undegassed melt, respectively. Concentrations of fluorine of about 7000 ppm are about equal in matrix glass and glass inclusions, indicating little degassing of fluorine during eruption. Chlorine contents amount to 1200 ppm in the inclusions, and to about 1000 ppm in matrix glass. The concentration difference, multiplied by erupted magma mass, suggests a total chlorine emission of 16 Mt. Apparently only little chlorine exsolved in the initial eruption phase, but degassing strongly increased during the plinian phase. Sulphur concentrations

  10. MAGNETIC TOPOLOGY OF BUBBLES IN QUIESCENT PROMINENCES

    International Nuclear Information System (INIS)

    Dudík, J.; Aulanier, G.; Schmieder, B.; Zapiór, M.; Heinzel, P.

    2012-01-01

    We study a polar-crown prominence with a bubble and its plume observed in several coronal filters by the SDO/AIA and in Hα by the MSDP spectrograph in Białków (Poland) to address the following questions: what is the brightness of prominence bubbles in EUV with respect to the corona outside of the prominence and the prominence coronal cavity? What is the geometry and topology of the magnetic field in the bubble? What is the nature of the vertical threads seen within prominences? We find that the brightness of the bubble and plume is lower than the brightness of the corona outside of the prominence, and is similar to that of the coronal cavity. We constructed linear force-free models of prominences with bubbles, where the flux rope is perturbed by inclusion of parasitic bipoles. The arcade field lines of the bipole create the bubble, which is thus devoid of magnetic dips. Shearing the bipole or adding a second one can lead to cusp-shaped prominences with bubbles similar to the observed ones. The bubbles have complex magnetic topology, with a pair of coronal magnetic null points linked by a separator outlining the boundary between the bubble and the prominence body. We conjecture that plume formation involves magnetic reconnection at the separator. Depending on the viewing angle, the prominence can appear either anvil-shaped with predominantly horizontal structures, or cusp-shaped with predominantly vertical structuring. The latter is an artifact of the alignment of magnetic dips with respect to the prominence axis and the line of sight.

  11. Stable isotope and petrologic evidence for open-system degassing during the climactic and pre-climactic eruptions of Mt. Mazama, Crater Lake, Oregon

    Science.gov (United States)

    Mandeville, Charles W.; Webster, James D.; Tappen, Christine; Taylor, Bruce E.; Timbal, Adrian; Sasaki, Akira; Hauri, Erik; Bacon, Charles R.

    2009-05-01

    Evaluation of the extent of volatile element recycling in convergent margin volcanism requires delineating likely source(s) of magmatic volatiles through stable isotopic characterization of sulfur, hydrogen and oxygen in erupted tephra with appropriate assessment of modification by degassing. The climactic eruption of Mt. Mazama ejected approximately 50 km 3 of rhyodacitic magma into the atmosphere and resulted in formation of a 10-km diameter caldera now occupied by Crater Lake, Oregon (lat. 43°N, long. 122°W). Isotopic compositions of whole-rocks, matrix glasses and minerals from Mt. Mazama climactic, pre-climactic and postcaldera tephra were determined to identify the likely source(s) of H 2O and S. Integration of stable isotopic data with petrologic data from melt inclusions has allowed for estimation of pre-eruptive dissolved volatile concentrations and placed constraints on the extent, conditions and style of degassing. Sulfur isotope analyses of climactic rhyodacitic whole rocks yield δ 34S values of 2.8-14.8‰ with corresponding matrix glass values of 2.4-13.2‰. δ 34S tends to increase with stratigraphic height through climactic eruptive units, consistent with open-system degassing. Dissolved sulfur concentrations in melt inclusions (MIs) from pre-climactic and climactic rhyodacitic pumices varies from 80 to 330 ppm, with highest concentrations in inclusions with 4.8-5.2 wt% H 2O (by FTIR). Up to 50% of the initial S may have been lost through pre-eruptive degassing at depths of 4-5 km. Ion microprobe analyses of pyrrhotite in climactic rhyodacitic tephra and andesitic scoria indicate a range in δ 34S from -0.4‰ to 5.8‰ and from -0.1‰ to 3.5‰, respectively. Initial δ 34S values of rhyodacitic and andesitic magmas were likely near the mantle value of 0‰. Hydrogen isotope (δD) and total H 2O analyses of rhyodacitic obsidian (and vitrophyre) from the climactic fall deposit yielded values οf -103 to -53‰ and 0.23-1.74 wt%, respectively

  12. Cyclical Variability of Prominences, CMEs and Flares

    Indian Academy of Sciences (India)

    ... Refresher Courses · Symposia · Live Streaming. Home; Journals; Journal of Astrophysics and Astronomy; Volume 21; Issue 3-4. Cyclical Variability of Prominences, CMEs and Flares. J. L. Ballester. Session V – Vector Magnetic Fields, Prominences, CMEs & Flares Volume 21 Issue 3-4 September-December 2000 pp ...

  13. Cyclical Variability of Prominences, CMEs and Flares

    Indian Academy of Sciences (India)

    tribpo

    These zones are: (a) Zone of sunspot type prominences which move along with sunspots originating between 30° and 50°; (b) Zone of long-lived prominences which develop from active centers, migrating towards the equator at a latitude 15° higher than the spot zone; (c) Polar zone at latitudes higher than 45°. Since Secchi.

  14. [Mechanisms of tooth eruption].

    Science.gov (United States)

    Maltha, J C

    2014-04-01

    Tooth eruption is of the utmost importance for the normal development of the dentition and the face. Since the 1980s, it has been known that the tooth germ itself is not essential for facilitating the processes that make tooth eruption possible. For that reason, recent research on the regulatory mechanisms of tooth eruption has focused mainly on the enamel organ and the dental follicle. Different regulatory mechanisms act on the occlusal and the apical sides of an erupting tooth. On the occlusal side osteoclast differentiation is stimulated. This leads to the development of an eruption canal, a process in which macrophages and matrix metalloproteases also play an important role. On the apical side the most important factors are the transcription factor RUNX2 and the bone morphogenic protein 2. They are responsible for the deposition of trabecular bone in that area. Many regulatory mechanisms which are involved in tooth eruption are also active in other developmental processes. This explains that certain syndromes can also have an effect on the tooth eruption process.

  15. Medical effects of volcanic eruptions

    Science.gov (United States)

    Baxter, Peter J.

    1990-09-01

    Excluding famine and tsunamis, most deaths in volcanic eruptions have been from pyroclastic flows and surges (nuées ardentes) and wet debris flows (lahars). Information on the causes of death and injury in eruptions is sparse but the available literature is summarised for the benefit of volcanologists and emergency planners. In nuées, thermal injury may be at least as important as asphyxia in causing immediate deaths. The high temperature of the gases and entrained particles readily causes severe burns to the skin and the air passages and the presence of both types of injury in an individual may combine to increase the delayed mortality risk from respiratory complications or from infection of burns. Trauma from missiles or body displacement is also common, but the role of asphyxiant or irritant gases, and steam, remains unclear. The ratio of dead: injured is much higher than in other natural disasters. At the periphery of a nuée being protected inside buildings which remain intact appears to greatly increase the chances of survival. In lahars, infected wounds and crush injury are the main delayed causes of death, and the scope for preventive measures, other than evacuation, is small. The evidence from Mount St. Helens, 1980, and other major eruptions indicates that, although mortality is high within the main zone of devastation and in the open, emergency planning should concentrate on the periphery of a nuée where preventive measures are feasible and could save many lives in densely populated areas.

  16. The hazards of eruptions through lakes and seawater

    Science.gov (United States)

    Mastin, L.G.; Witter, J.B.

    2000-01-01

    Eruptions through crater lakes or shallow seawater, referred to here as subaqueous eruptions, present hazards from hydromagmatic explosions, such as base surges, lahars, and tsunamis, which may not exist at volcanoes on dry land. We have systematically compiled information from eruptions through surface water in order to understand the circumstances under which these hazards occur and what disastrous effects they have caused in the past. Subaqueous eruptions represent only 8% of all recorded eruptions but have produced about 20% of all fatalities associated with volcanic activity in historical time. Excluding eruptions that have resulted in about a hundred deaths or less, lahars have killed people in the largest number of historical subaqueous eruptions (8), followed by pyroclastic flows (excluding base surges; 5) tsunamis (4), and base surges (2). Subaqueous eruptions have produced lahars primarily on high (>1000 m), steep-sided volcanoes containing small (caused death or destroyed man-made structures only at submarine volcanoes and at Lake Taal in the Philippines. In spite of evidence that magma-water mixing makes eruptions more explosive, such explosions and their associated base surges have caused fewer deaths, and have been implicated in fewer eruptions involving large numbers of fatalities than lahars and tsunamis. The latter hazards are more deadly because they travel much farther from a volcano and inundate coastal areas and stream valleys that tend to be densely settled.

  17. Extreme pointer years in tree-ring records of Central Spain as evidence of climatic events and the eruption of the Huaynaputina Volcano (Peru, 1600 AD

    Directory of Open Access Journals (Sweden)

    M. Génova

    2012-04-01

    Full Text Available The study of pointer years of numerous tree-ring chronologies of the central Iberian Peninsula (Sierra de Guadarrama could provide complementary information about climate variability over the last 405 yr. In total, 64 pointer years have been identified: 30 negative (representing minimum growths and 34 positive (representing maximum growths, the most significant of these being 1601, 1963 and 1996 for the negative ones, and 1734 and 1737 for the positive ones. Given that summer precipitation was found to be the most limiting factor for the growth of Pinus in the Sierra de Guadarrama in the second half of the 20th century, it is also an explanatory factor in almost 50% of the extreme growths. Furthermore, these pointer years and intervals are not evenly distributed throughout time. Both in the first half of the 17th and in the second half of 20th, they were more frequent and more extreme and these periods are the most notable for the frequency of negative pointer years in Central Spain. The interval 1600–1602 is of special significance, being one of the most unfavourable for tree growth in the centre of Spain, with 1601 representing the minimum index in the regional chronology. We infer that this special minimum annual increase was the effect of the eruption of Huaynaputina, which occurred in Peru at the beginning of 1600 AD. This is the first time that the effects of this eruption in the tree-ring records of Southern Europe have been demonstrated.

  18. Micro-textures in plagioclase from 1994–1995 eruption, Barren Island Volcano: Evidence of dynamic magma plumbing system in the Andaman subduction zone

    Directory of Open Access Journals (Sweden)

    M.L. Renjith

    2014-01-01

    Full Text Available A systematic account of micro-textures and a few compositional profiles of plagioclase from high-alumina basaltic aa lava erupted during the year 1994–1995, from Barren Island Volcano, NE India ocean, are presented for the first time. The identified micro-textures can be grouped into two categories: (i Growth related textures in the form of coarse/fine-sieve morphology, fine-scale oscillatory zoning and resorption surfaces resulted when the equilibrium at the crystal-melt interface was fluctuated due to change in temperature or H2O or pressure or composition of the crystallizing melt; and (ii morphological texture, like glomerocryst, synneusis, swallow-tailed crystal, microlite and broken crystals, formed by the influence of dynamic behavior of the crystallizing magma (convection, turbulence, degassing, etc.. Each micro-texture has developed in a specific magmatic environment, accordingly, a first order magma plumbing model and crystallization dynamics are envisaged for the studied lava unit. Magma generated has undergone extensive fractional crystallization of An-rich plagioclase in stable magmatic environment at a deeper depth. Subsequently they ascend to a shallow chamber where the newly brought crystals and pre-existing crystals have undergone dynamic crystallization via dissolution-regrowth processes in a convective self-mixing environment. Such repeated recharge-recycling processes have produced various populations of plagioclase with different micro-textural stratigraphy in the studied lava unit. Intermittent degassing and eruption related decompression have also played a major role in the final stage of crystallization dynamics.

  19. Seasonality of volcanic eruptions

    Science.gov (United States)

    Mason, B. G.; Pyle, D. M.; Dade, W. B.; Jupp, T.

    2004-04-01

    An analysis of volcanic activity during the last three hundred years reveals that volcanic eruptions exhibit seasonality to a statistically significant degree. This remarkable pattern is observed primarily along the Pacific "Ring of Fire" and locally at some individual volcanoes. Globally, seasonal fluctuations amount to 18% of the historical average monthly eruption rate. In some regions, seasonal fluctuations amount to as much as 50% of the average eruption rate. Seasonality principally reflects the temporal distribution of the smaller, dated eruptions (volcanic explosivity index of 0-2) that dominate the eruption catalog. We suggest that the pattern of seasonality correlates with the annual Earth surface deformation that accompanies the movement of surface water mass during the annual hydrological cycle and illustrate this with respect to global models of surface deformation and regional measurements of annual sea level change. For example, seasonal peaks in the eruption rate of volcanoes in Central America, the Alaskan Peninsula, and Kamchatka coincide with periods of falling regional sea level. In Melanesia, in contrast, peak numbers of volcanic eruptions occur during months of maximal regional sea level and falling regional atmospheric pressure. We suggest that the well-documented slow deformation of Earth's surface that accompanies the annual movements of water mass from oceans to continents acts to impose a fluctuating boundary condition on volcanoes, such that volcanic eruptions tend to be concentrated during periods of local or regional surface change rather than simply being distributed randomly throughout the year. Our findings have important ramifications for volcanic risk assessment and volcanoclimate feedback mechanisms.

  20. An erupted complex odontoma.

    Science.gov (United States)

    Tozoglu, Sinan; Yildirim, Umran; Buyukkurt, M Cemil

    2010-01-01

    Odontomas are benign tumors of odontogenic origin. The cause of the odontoma is unknown, but it is believed to be hereditary or due to a disturbance in tooth development triggered by trauma or infection. Odontomas may be either compound or complex. Although these tumors are seen frequently, erupted odontomas are rare. The purpose of this study is to present a rare case of complex odontoma that erupted into the oral cavity.

  1. MHD Simulations of the Eruption of Coronal Flux Ropes under Coronal Streamers

    Science.gov (United States)

    Fan, Yuhong

    2017-07-01

    Using three-dimensional magnetohydrodynamic (MHD) simulations, we investigate the eruption of coronal flux ropes underlying coronal streamers and the development of a prominence eruption. We initialize a quasi-steady solution of a coronal helmet streamer, into which we impose at the lower boundary the slow emergence of a part of a twisted magnetic torus. As a result, a quasi-equilibrium flux rope is built up under the streamer. With varying streamer sizes and different lengths and total twists of the flux rope that emerges, we found different scenarios for the evolution from quasi-equilibrium to eruption. In the cases with a broad streamer, the flux rope remains well confined until there is sufficient twist such that it first develops the kink instability and evolves through a sequence of kinked, confined states with increasing height until it eventually develops a “hernia-like” ejective eruption. For significantly twisted flux ropes, prominence condensations form in the dips of the twisted field lines due to runaway radiative cooling. Once formed, the prominence-carrying field becomes significantly non-force-free due to the weight of the prominence, despite having low plasma β. As the flux rope erupts, the prominence erupts, showing substantial draining along the legs of the erupting flux rope. The prominence may not show a kinked morphology even though the flux rope becomes kinked. On the other hand, in the case with a narrow streamer, the flux rope with less than one wind of twist can erupt via the onset of the torus instability.

  2. MHD Simulations of the Eruption of Coronal Flux Ropes under Coronal Streamers

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Yuhong, E-mail: yfan@ucar.edu [High Altitude Observatory, National Center for Atmospheric Research, 3080 Center Green Drive, Boulder, CO 80301 (United States)

    2017-07-20

    Using three-dimensional magnetohydrodynamic (MHD) simulations, we investigate the eruption of coronal flux ropes underlying coronal streamers and the development of a prominence eruption. We initialize a quasi-steady solution of a coronal helmet streamer, into which we impose at the lower boundary the slow emergence of a part of a twisted magnetic torus. As a result, a quasi-equilibrium flux rope is built up under the streamer. With varying streamer sizes and different lengths and total twists of the flux rope that emerges, we found different scenarios for the evolution from quasi-equilibrium to eruption. In the cases with a broad streamer, the flux rope remains well confined until there is sufficient twist such that it first develops the kink instability and evolves through a sequence of kinked, confined states with increasing height until it eventually develops a “hernia-like” ejective eruption. For significantly twisted flux ropes, prominence condensations form in the dips of the twisted field lines due to runaway radiative cooling. Once formed, the prominence-carrying field becomes significantly non-force-free due to the weight of the prominence, despite having low plasma β . As the flux rope erupts, the prominence erupts, showing substantial draining along the legs of the erupting flux rope. The prominence may not show a kinked morphology even though the flux rope becomes kinked. On the other hand, in the case with a narrow streamer, the flux rope with less than one wind of twist can erupt via the onset of the torus instability.

  3. Geodetic evidence for en echelon dike emplacement and concurrent slow slip during the June 2007 intrusion and eruption at Kīlauea volcano, Hawaii

    Science.gov (United States)

    Montgomery-Brown, E. K.; Sinnett, D.K.; Poland, M.; Segall, P.; Orr, T.; Zebker, H.; Miklius, Asta

    2010-01-01

    A series of complex events at Kīlauea Volcano, Hawaii, 17 June to 19 June 2007, began with an intrusion in the upper east rift zone (ERZ) and culminated with a small eruption (1500 m3). Surface deformation due to the intrusion was recorded in unprecedented detail by Global Positioning System (GPS) and tilt networks as well as interferometric synthetic aperture radar (InSAR) data acquired by the ENVISAT and ALOS satellites. A joint nonlinear inversion of GPS, tilt, and InSAR data yields a deflationary source beneath the summit caldera and an ENE-striking uniform-opening dislocation with ~2 m opening, a dip of ∼80° to the south, and extending from the surface to ~2 km depth. This simple model reasonably fits the overall pattern of deformation but significantly misfits data near the western end of an inferred dike-like source. Three more complex dike models are tested that allow for distributed opening including (1) a dike that follows the surface trace of the active rift zone, (2) a dike that follows the symmetry axis of InSAR deformation, and (3) two en echelon dike segments beneath mapped surface cracks and newly formed steaming areas. The en echelon dike model best fits near-field GPS and tilt data. Maximum opening of 2.4 m occurred on the eastern segment beneath the eruptive vent. Although this model represents the best fit to the ERZ data, it still fails to explain data from a coastal tiltmeter and GPS sites on Kīlauea's southwestern flank. The southwest flank GPS sites and the coastal tiltmeter exhibit deformation consistent with observations of previous slow slip events beneath Kīlauea's south flank, but inconsistent with observations of previous intrusions. Slow slip events at Kīlauea and elsewhere are thought to occur in a transition zone between locked and stably sliding zones of a fault. An inversion including slip on a basal decollement improves fit to these data and suggests a maximum of ~15 cm of seaward fault motion, comparable to previous slow

  4. Energy release from a stream of infalling prominence debris on 2011 September 7-8

    Science.gov (United States)

    Inglis, A. R.; Gilbert, H. R.; Ofman, L.

    2017-12-01

    In recent years high-resolution and high-cadence EUV imaging has revealed a new phenomenon, impacting prominence debris, where prominence material from failed or partial eruptions can impact the lower atmosphere and release energy. We present a clear example of this phenomenon occurring on 2011 September 7-8. The initial eruption of prominence material was associated with an X1.8-class flare from AR11283, occurring at 22:30 UT on 2011 September 7, resulting in a semi-continuous stream of this material returning to the solar surface between 00:20 - 00:40 UT on 2011 September 8. A substantial area remote from the original active region experienced brightening in multiple EUV channels observed by SDO/AIA. Using the differential emission measure, we estimated the energetic properties of this event. We found that the radiated energy of the impacted plasma was of order 10^27 ergs, while the upper limit on the thermal energy peaked at 10^28 ergs. Based on these estimates we were able to determine the mass content of the debris to be in the range 2x10^14 energy release takes place during these events, and that such impacts may be used as a novel diagnostic tool for investigating prominence material properties.

  5. Age and impacts of the caldera-forming Aniakchak II eruption in western Alaska

    NARCIS (Netherlands)

    Blackford, J. J.; Payne, R. J.; Heggen, M. P.; Caballero, A. de la Riva; van der Plicht, J.

    The mid-Holocene eruption of Aniakchak volcano (Aniakchak II) in southwest Alaska was among the largest eruptions globally in the last 10,000 years (VEI-6). Despite evidence for possible impacts on global climate, the precise age of the eruption is not well-constrained and little is known about

  6. Volcanic eruptions on Io

    Science.gov (United States)

    Strom, R. G.; Schneider, N. M.; Terrile, R. J.; Cook, A. F.; Hansen, C.

    1981-09-01

    Nine eruption plumes which were observed during the Voyager 1 encounter with Io are discussed. During the Voyager 2 encounter, four months later, eight of the eruptions were still active although the largest became inactive sometime between the two encounters. Plumes range in height from 60 to over 300 km with corresponding ejection velocities of 0.5 to 1.0 km/s and plume sources are located on several plains and consist of fissures or calderas. The shape and brightness distribution together with the pattern of the surface deposition on a plume 3 is simulated by a ballistic model with a constant ejection velocity of 0.5 km/s and ejection angles which vary from 0-55 deg. The distribution of active and recent eruptions is concentrated in the equatorial regions and indicates that volcanic activity is more frequent and intense in the equatorial regions than in the polar regions. Due to the geologic setting of certain plume sources and large reservoirs of volatiles required for the active eruptions, it is concluded that sulfur volcanism rather than silicate volcanism is the most likely driving mechanism for the eruption plumes.

  7. SOLAR LIMB PROMINENCE CATCHER AND TRACKER (SLIPCAT): AN AUTOMATED SYSTEM AND ITS PRELIMINARY STATISTICAL RESULTS

    International Nuclear Information System (INIS)

    Wang Yuming; Cao Hao; Chen Junhong; Zhang Tengfei; Yu Sijie; Zheng Huinan; Shen Chenglong; Wang, S.; Zhang Jie

    2010-01-01

    In this paper, we present an automated system, which has the capability to catch and track solar limb prominences based on observations from the extreme-ultraviolet (EUV) 304 A passband. The characteristic parameters and their evolution, including height, position angle, area, length, and brightness, are obtained without manual interventions. By applying the system to the STEREO-B/SECCHI/EUVI 304 A data during 2007 April-2009 October, we obtain a total of 9477 well-tracked prominences and a catalog of these events available online. A detailed analysis of these prominences suggests that the system has a rather good performance. We have obtained several interesting statistical results based on the catalog. Most prominences appear below the latitude of 60 0 and at the height of about 26 Mm above the solar surface. Most of them are quite stable during the period they are tracked. Nevertheless, some prominences have an upward speed of more than 100 km s -1 , and some others show significant downward and/or azimuthal speeds. There are strong correlations among the brightness, area, and height. The expansion of a prominence is probably one major cause of its fading during the rising or erupting process.

  8. Filament Eruptions, Jets, and Space Weather

    Science.gov (United States)

    Moore, Ronald; Sterling, Alphonse; Robe, Nick; Falconer, David; Cirtain, Jonathan

    2013-01-01

    -plasma component of coronal X-ray jets. This favors the idea that Type-II spicules are miniature counterparts of coronal X-ray jets. In Moore et al (2011, ApJ, 731, L18), we pointed out that if Type-II spicules are magnetic eruptions that work like coronal X-ray jets, they carry an area-averaged mechanical energy flux of approximately 7x10)(exp 5) erg cm(exp -2) s(exp-1) into the corona in the form of MHD waves and jet outflow, enough to power the heating of the global corona and solar wind. On this basis, from our observations of mini-filament eruptions in blowout X-ray jets, we infer that magnetic explosions of the type that have erupting filaments in them are the main engines of both (1) the steady solar wind and (2) the CMEs that produce the most severe space weather by blasting out through the corona and solar wind, making solar energetic particle storms, and bashing the Earth's magnetosphere. We conclude that in focusing on prominences and filament eruptions, Einar had his eye on the main bet for understanding what powers all space weather, both the extreme and the normal.

  9. Exploring the properties of Solar Prominence Tornados

    Science.gov (United States)

    Ahmad, E.; Panesar, N. K.; Sterling, A. C.; Moore, R. L.

    2015-12-01

    Solar prominences consist of relatively cool and dense plasma embedded in the hotter solar corona above the solar limb. They form along magnetic polarity inversion lines, and are magnetically supported against gravity at heights of up to ~100 Mm above the chromosphere. Often, parts of prominences visually resemble Earth-based tornados, with inverted-cone-shaped structures and internal motions suggestive of rotation. These "prominence tornados" clearly possess complex magnetic structure, but it is still not certain whether they actually rotate around a ''rotation'' axis, or instead just appear to do so because of composite internal material motions such as counter-streaming flows or lateral (i.e. transverse to the field) oscillations. Here we study the structure and dynamics of five randomly selected prominences, using extreme ultraviolet (EUV) 171 Å images obtained with high spatial and temporal resolution by the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) spacecraft. All of the prominences resided in non-active-region locations, and displayed what appeared to be tornado-like rotational motions. Our set includes examples oriented both broadside and end-on to our line-of-sight. We created time-distance plots of horizontal slices at several different heights of each prominence, to study the horizontal plasma motions. We observed patterns of oscillations at various heights in each prominence, and we measured parameters of these oscillations. We find the oscillation time periods to range over ~50 - 90 min, with average amplitudes of ~6,000 km, and with average velocities of ~7 kms-1. We found similar values for prominences viewed either broadside or end-on; this observed isotropy of the lateral oscillatory motion suggests that the apparent oscillations result from actual rotational plasma motions and/or lateral oscillations of the magnetic field, rather than to counter-streaming flows. This research was supported by the National

  10. Impaired tooth eruption: a review.

    Science.gov (United States)

    Noffke, C E E; Chabikuli, N J; Nzima, N

    2005-11-01

    Eruption is the continuous process of movement of a tooth from its developmental location inside the jaw to its functional location in the mouth. Impaired tooth eruption, where this process is disturbed, is common in dental practice. It may manifest either as delayed or complete absence of eruption. Although unerupted teeth are usually asymptomatic, they may cause cosmetic and pathologic complications. The purpose of this article is to provide a review on the pathogenesis and differential radiographic interpretation of impaired tooth eruption.

  11. Kink-induced full and failed eruptions of two coupled flux tubes of the same filament

    Science.gov (United States)

    Dechev, M.; Koleva, K.; Duchlev, P.

    2018-02-01

    In this work, we report results from the study of a filament/prominence eruption on 2014 May 4. This eruption belongs to the class of rarely reported causally linked eruptions of two coupled flux tubes (FTs) of a quiet region filament. We made a comparative analysis based on multiwave observations from Solar Dynamics Observatory (SDO) and Solar Terrestrial Relations Observatory (STEREO) A and B combining the high temporal and spatial data taken from three different viewpoints. The main results of the study are as follows: (1) The source of the eruptive prominence consists of two coupled FTs located near the eastern limb: top-located one (FT1) and bottom-located one (FT2). (2) FT1 and FT2 had the same helicity, i.e. left-handed twist and writhe. Their untwisting motion during eruption suggests that kink instability seems to act. (3) The kinematic evolution of the FT1 suggests a slow successful eruption that was associated with a slow CME. (4) The FT2 exhibited failed kinked eruption with a non-radial propagation followed by its reformation. This eruption was accompanied of apparent mass draining in the legs, flare-ribbons and post-flare EUV arcade.

  12. [Tooth eruption disturbances and syndromes

    NARCIS (Netherlands)

    Oosterkamp, B.A.M. van; Ockeloen, C.W.; Carels, C.E.L.; Kuijpers-Jagtman, A.M.

    2014-01-01

    In the tooth eruption mechanism, various disturbances can appear as a result of gene mutations, a consequence of which can be that tooth eruption does not occur. There are 5 syndromes which involve the complete failure of several or even all teeth to erupt, specifically: cleidocranial dysplasia,

  13. Volcanic Eruptions and Climate

    Science.gov (United States)

    LeGrande, Allegra N.; Anchukaitis, Kevin J.

    2015-01-01

    Volcanic eruptions represent some of the most climatically important and societally disruptive short-term events in human history. Large eruptions inject ash, dust, sulfurous gases (e.g. SO2, H2S), halogens (e.g. Hcl and Hbr), and water vapor into the Earth's atmosphere. Sulfurous emissions principally interact with the climate by converting into sulfate aerosols that reduce incoming solar radiation, warming the stratosphere and altering ozone creation, reducing global mean surface temperature, and suppressing the hydrological cycle. In this issue, we focus on the history, processes, and consequences of these large eruptions that inject enough material into the stratosphere to significantly affect the climate system. In terms of the changes wrought on the energy balance of the Earth System, these transient events can temporarily have a radiative forcing magnitude larger than the range of solar, greenhouse gas, and land use variability over the last millennium. In simulations as well as modern and paleoclimate observations, volcanic eruptions cause large inter-annual to decadal-scale changes in climate. Active debates persist concerning their role in longer-term (multi-decadal to centennial) modification of the Earth System, however.

  14. Eruption on Io

    Science.gov (United States)

    1996-01-01

    This image, taken by NASA's Galileo spacecraft, shows a new blue-colored volcanic plume extending about 100 kilometers (about 60 miles) into space from Jupiter's moon Io (see inset at lower left). The blue color of the plume is consistent with the presence of sulfur dioxide gas and 'snow' condensing from the gas as the plume expands and cools. Galileo images have also shown that the Ra Patera plume glows in the dark, perhaps due to the fluorescence of sulfur and oxygen ions created by the breaking apart of sulfur dioxide molecules by energetic particles in the Jovian magnetosphere. The images at right show a comparison of changes seen near the volcano Ra Patera since the Voyager spacecraft flybys of 1979 (windows at right show Voyager image at top and Galileo image at bottom). This eruptive plume is an example of a new type of volcanic activity discovered during Voyager's flyby in 1979, believed to be geyser-like eruptions driven by sulfur dioxide or sulfur gas erupting and freezing in Io's extremely tenuous atmosphere. Volcanic eruptions on Earth cannot throw materials to such high altitudes. Ra Patera is the site of dramatic surface changes. An area around the volcano of about 40,000 square kilometers, area about the size of New Jersey, has been covered by new volcanic deposits. The image was taken in late June 28, 1996 from a distance of 972,000 kilometers (604,000 miles). The Galileo mission is managed by NASA's Jet Propulsion Laboratory.

  15. Sulfur budget and global climate impact of the A.D. 1835 eruption of Cosigüina volcano, Nicaragua

    Science.gov (United States)

    Longpré, Marc-Antoine; Stix, John; Burkert, Cosima; Hansteen, Thor; Kutterolf, Steffen

    2014-10-01

    Large explosive volcanic eruptions can inject massive amounts of sulfuric gases into the Earth's atmosphere and, in so doing, affect global climate. The January 1835 eruption of Cosigüina volcano, Nicaragua, ranks among the Americas' largest and most explosive historical eruptions, but whether it had effects on global climate remains ambiguous. New petrologic analyses of the Cosigüina deposits reveal that the eruption released enough sulfur to explain a prominent circa A.D. 1835 sulfate anomaly in ice cores from both the Arctic and Antarctic. A compilation of temperature-sensitive tree ring chronologies indicates appreciable cooling of the Earth's surface in response to the eruption, consistent with instrumental temperature records. We conclude that this eruption represents one of the most important sulfur-producing events of the last few centuries and had a sizable climate impact rivaling that of the 1991 eruption of Mount Pinatubo.

  16. Explosive volcanism on Mercury: Analysis of vent and deposit morphology and modes of eruption

    Science.gov (United States)

    Jozwiak, Lauren M.; Head, James W.; Wilson, Lionel

    2018-03-01

    The MESSENGER mission revealed, for the first time, conclusive evidence of explosive volcanism on Mercury. Several previous works have cataloged the appearance and location of explosive volcanism on the planet using a variety of identifying characteristics, including vent presence and deposit color as seen in multispectral image mosaics. We present here a comprehensive catalog of vents of likely volcanic origin; our classification scheme emphasizes vent morphology. We have analyzed the morphologies of all vents in our catalog, and recognize three main morphologies: "simple vent", "pit vent", and "vent-with-mound". The majority of vents we identify are located within impact craters. The spatial distribution of vents does not correlate with the locations of volcanic smooth plains deposits, in contrast to the Moon, nor do vents correlate with the locations of large impact basins (except for the Caloris and Tolstoj basins). Using the degradation state of the vent host crater as a proxy for maximum age, we suggest that vent formation has been active through the Mansurian and into the Kuiperian periods, although the majority of vents were likely formed much earlier in mercurian history. The morphologies and locations of vents are used to investigate a set of plausible formation geometries. We find that the most likely and most prevalent formation geometry is that of a dike, stalled at depth, which then explosively vents to the surface. We compare the vent and deposit size of mercurian pyroclastic deposits with localized and regional lunar pyroclastic deposits, and find a range of possible eruption energies and corresponding variations in eruption style. Localized lunar pyroclastic deposits and the majority of mercurian pyroclastic deposits show evidence for eruption that is consistent with the magmatic foam at the top of a dike reaching a critical gas volume fraction. A subset of mercurian vents, including the prominent Copland-Rachmaninoff vent to the northeast of the

  17. [Tooth eruption disturbances and syndromes].

    Science.gov (United States)

    Oosterkamp, B C M; Ockeloen, C W; Carels, C E L; Kuijpers-Jagtman, A M

    2014-04-01

    In the tooth eruption mechanism, various disturbances can appear as a result of gene mutations, a consequence of which can be that tooth eruption does not occur. There are 5 syndromes which involve the complete failure of several or even all teeth to erupt, specifically: cleidocranial dysplasia, Gardner's syndrome, osteopetrosis, mucopolysaccharidosis and GAPO syndrome. Some are very rare and will seldom be encountered in a dental practice, but they show how vulnerable the tooth eruption mechanism is. Dentists are generally the ones who identify a tooth eruption problem in a patient. Since syndromes can be associated with other disorders, additional investigation by a clinical geneticist is always important when a syndrome is suspected.

  18. Orthodontic treatment for prominent upper front teeth (Class II malocclusion) in children and adolescents.

    Science.gov (United States)

    Batista, Klaus Bsl; Thiruvenkatachari, Badri; Harrison, Jayne E; O'Brien, Kevin D

    2018-03-13

    Prominent upper front teeth are a common problem affecting about a quarter of 12-year-old children in the UK. The condition develops when permanent teeth erupt. These teeth are more likely to be injured and their appearance can cause significant distress. Children are often referred to an orthodontist for treatment with dental braces to reduce the prominence of their teeth. If a child is referred at a young age, the orthodontist is faced with the dilemma of whether to treat the patient early or to wait and provide treatment in adolescence. To assess the effects of orthodontic treatment for prominent upper front teeth initiated when children are seven to 11 years old ('early treatment' in two phases) compared to in adolescence at around 12 to 16 years old ('late treatment' in one phase); to assess the effects of late treatment compared to no treatment; and to assess the effects of different types of orthodontic braces. Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 27 September 2017), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2017, Issue 8), MEDLINE Ovid (1946 to 27 September 2017), and Embase Ovid (1980 to 27 September 2017). The US National Institutes of Health Ongoing Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. Randomised controlled trials of orthodontic treatments to correct prominent upper front teeth (Class II malocclusion) in children and adolescents. We included trials that compared early treatment in children (two-phase) with any type of orthodontic braces (removable, fixed, functional) or head-braces versus late treatment in adolescents (one-phase) with any type of orthodontic braces or head-braces, and trials that compared any

  19. Generalized Eruptive Syringoma

    Directory of Open Access Journals (Sweden)

    Aysun Şikar Aktürk

    2011-12-01

    Full Text Available Syringoma is a benign adnexal tumor arising from eccrine sweat gland ducts and is more commonly seen in women. It is characterized by skin-coloured or yellowish small papules localized generally in the periorbital region. Generalized eruptive syringoma is also a rare clinical variant of syringoma in which lesions are localized and widespread in the body. Lesions, which usually start to occur in the peripubertal period, can show spontaneous resolution. In unresolved cases, treatment methods such as topical tretinoin or adapalene, excision, electrocoagulation, cryotherapy, and carbon dioxide (CO2 laser may be tried. In this report, a 24 year-old female patient with symmetrically distributed multiple skin-coloured or yellowish small papules on the periorbital region, upper anterior chest and upper arm appearing during the peripubertal period and diagnosed as generalized eruptive syringoma has been reported.

  20. Large erupted complex odontoma

    Directory of Open Access Journals (Sweden)

    Vijeev Vasudevan

    2009-01-01

    Full Text Available Odontomas are a heterogeneous group of jaw bone lesions, classified as odontogenic tumors which usually include well-diversified dental tissues. Odontoma is a term introduced to the literature by Broca in 1867. Trauma, infection and hereditary factors are the possible causes of forming this kind of lesions. Among odontogenic tumors, they constitute about 2/3 of cases. These lesions usually develop slowly and asymptomatically, and in most cases they do not cross the bone borders. Two types of odontoma are recognized: compound and complex. Complex odontomas are less common than the compound variety in the ratio 1:2.3. Eruption of an odontoma in the oral cavity is rare. We present a case of complex odontoma, in which apparent eruption has occurred in the area of the right maxillary second molar region.

  1. Choosing a scale for measuring perceived prominence

    DEFF Research Database (Denmark)

    Jensen, Christian; Tøndering, John

    2005-01-01

    Three different scales which have been used to measure perceived prominence are evaluated in a perceptual experiment. Average scores of raters using a multi-level (31-point) scale, a simple binary (2-point) scale and an intermediate 4-point scale are almost identical. The potentially finer...... gradation possible with the multi-level scale(s) is compensated for by having multiple listeners, which is a also a requirement for obtaining reliable data. In other words, a high number of levels is neither a sufficient nor a necessary requirement. Overall the best results were obtained using the 4-point...

  2. Volcanology and hazards of phreatomagmatic basaltic eruptions

    DEFF Research Database (Denmark)

    Schmith, Johanne

    showed that subglacial eruptions were controlled by both magmatic and phreatomagmatic fragmentation processes. Further investigations determined the RI of consecutive depositional units of both the 1755 and 1625 eruptions. The detailed models showed that the fragmentation processes in the 1755 eruption...... change significantly during subglacial eruptions and that magmatic processes play an important role in the fragmentation process. The RI study was combined with field data on deposit stratigraphy, granulometric modeling, componentry, and written accounts of the eruptions and produced a coherent model...... of the evolution of the eruptions. The collective data set shows that the 1755 eruption was a continuous uprush eruption much like the recent 2011 Grímsvötn eruption. However, the 1755 Katla eruption had a longer duration of 17 days and a higher mass eruption rate. The 1625 eruption was a dynamic eruption less...

  3. Hydrogen line formation in the quescent prominences

    International Nuclear Information System (INIS)

    Tsovookhuu, Ch.

    1980-01-01

    Equations of transfer and statistical equilibrium for hydronen atom with eight bound levels and continuum are solved simultaneously. A plane-parallel layer located perpendicular to the Sun surface is taken as a geometrical model. Input parameters of the physical model are optical thickness in the center of Hsub(α) line, electron temperature and concentration in the layer center are well as temperature and density gradients. Functions of sources, line profiles, total energies and the Balmer decrements, which are compared with observations and theoretical calculations made by other authors, have been calculated. The comparison shows that the results are quite acceptable and can be used when analyzing the spectrum and determining physical parameters of solar prominences. Dependence of different performances of the line (equivalent width, central intensity, halfwidth, depth of central depression etc.) on values of initial model parameters is investigated. Line halfwidth is more sensitive to the temperatuu value in the layer center, while central intensity - to the value of temperature gradient and a depth of central depression - to electron concentration. Calculated were shares of primary sources responsible for different excitation mechanism depending on total optical thickness as well as mean probabilities of quantum yield out of a medium which can be used during parametric accountancy of radiation diffusion in solar prominences [ru

  4. Early eruption of permanent canines

    Directory of Open Access Journals (Sweden)

    S Madhu

    2012-01-01

    Full Text Available Systemic and local factors can modify the eruption time of teeth. Generalized eruption time changes could be due to some systemic diseases like hyperthyroidism, hypophosphatasia, precocious puberty, Proteus syndrome, etc. Localized early eruption of permanent teeth could be due to early extraction of deciduous teeth. Presented here is an extremely rare case of early eruption of permanent canines in a 7-year old female child. Though the number of such cases is very limited, the clinician should poses adequate knowledge and keeps an open eye to identify such cases.

  5. Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or causality?

    Directory of Open Access Journals (Sweden)

    R. Funiciello

    2008-06-01

    Full Text Available Anecdotes of concurrent eruptions at Etna, Stromboli, and Vulcano (Southern Italy have persisted for more than 2000 years and volcanologists in recent and past times have hypothesized a causal link among these volcanoes. Here this hypothesis is tested. To introduce the problem and provide examples of the type of expected volcanic phenomena, narratives of the most notable examples of concurrent eruptions are provided. Then the frequency of eruptions at each individual volcano is analysed for about the last 300 years and the expected probability of concurrent eruptions is calculated to compare it to the observed probability. Results show that the occurrence of concurrent eruptions is often more frequent than a random probability, particularly for the Stromboli-Vulcano pair. These results are integrated with a statistical analysis of the earthquake catalogue to find evidence of linked seismicity in the Etnean and Aeolian areas. Results suggest a moderate incidence of non-random concurrent eruptions, but available data are temporally limited and do not allow an unequivocal identification of plausible triggers; our results, however, are the first attempt to quantify a more-than-2000-years-old curious observation and constitute a starting point for more sophisticated analyses of new data in the future. We look forward to our prediction of a moderate incidence of concurrent eruptions being confirmed or refuted with the passage of time and occurrence of new events.

  6. Observation of the Kelvin–Helmholtz Instability in a Solar Prominence

    Science.gov (United States)

    Yang, Heesu; Xu, Zhi; Lim, Eun-Kyung; Kim, Sujin; Cho, Kyung-Suk; Kim, Yeon-Han; Chae, Jongchul; Cho, Kyuhyoun; Ji, Kaifan

    2018-04-01

    Many solar prominences end their lives in eruptions or abrupt disappearances that are associated with dynamical or thermal instabilities. Such instabilities are important because they may be responsible for energy transport and conversion. We present a clear observation of a streaming kink-mode Kelvin–Helmholtz Instability (KHI) taking place in a solar prominence using the Hα Lyot filter installed at the New Vacuum Solar Telescope, Fuxian-lake Solar Observatory in Yunnan, China. On one side of the prominence, a series of plasma blobs floated up from the chromosphere and streamed parallel to the limb. The plasma stream was accelerated to about 20–60 km s‑1 and then undulated. We found that 2″- and 5″-size vortices formed, floated along the stream, and then broke up. After the 5″-size vortex, a plasma ejection out of the stream was detected in the Solar Dynamics Observatory/Atmospheric Imaging Assembly images. Just before the formation of the 5″-size vortex, the stream displayed an oscillatory transverse motion with a period of 255 s with the amplitude growing at the rate of 0.001 s‑1. We attribute this oscillation of the stream and the subsequent formation of the vortex to the KHI triggered by velocity shear between the stream, guided by the magnetic field and the surrounding media. The plasma ejection suggests the transport of prominence material into the upper layer by the KHI in its nonlinear stage.

  7. The physics of large eruptions

    Science.gov (United States)

    Gudmundsson, Agust

    2015-04-01

    Based on eruptive volumes, eruptions can be classified as follows: small if the volumes are from less than 0.001 km3 to 0.1 km3, moderate if the volumes are from 0.1 to 10 km3, and large if the volumes are from 10 km3 to 1000 km3 or larger. The largest known explosive and effusive eruptions have eruptive volumes of 4000-5000 km3. The physics of small to moderate eruptions is reasonably well understood. For a typical mafic magma chamber in a crust that behaves as elastic, about 0.1% of the magma leaves the chamber (erupted and injected as a dyke) during rupture and eruption. Similarly, for a typical felsic magma chamber, the eruptive/injected volume during rupture and eruption is about 4%. To provide small to moderate eruptions, chamber volumes of the order of several tens to several hundred cubic kilometres would be needed. Shallow crustal chambers of these sizes are common, and deep-crustal and upper-mantle reservoirs of thousands of cubic kilometres exist. Thus, elastic and poro-elastic chambers of typical volumes can account for small to moderate eruptive volumes. When the eruptions become large, with volumes of tens or hundreds of cubic kilometres or more, an ordinary poro-elastic mechanism can no longer explain the eruptive volumes. The required sizes of the magma chambers and reservoirs to explain such volumes are simply too large to be plausible. Here I propose that the mechanics of large eruptions is fundamentally different from that of small to moderate eruptions. More specifically, I suggest that all large eruptions derive their magmas from chambers and reservoirs whose total cavity-volumes are mechanically reduced very much during the eruption. There are two mechanisms by which chamber/reservoir cavity-volumes can be reduced rapidly so as to squeeze out much of, or all, their magmas. One is piston-like caldera collapse. The other is graben subsidence. During large slip on the ring-faults/graben-faults the associated chamber/reservoir shrinks in volume

  8. Peripheral compound odontoma erupting in the gingiva.

    Science.gov (United States)

    Hanemann, João A C; Oliveira, Denise T; Garcia, Natália Galvão; Santos, Mariana R G; Pereira, Alessandro A C

    2013-06-11

    Peripheral odontoma arising in the extraosseous soft tissues is rare and if not removed early, may enlarge over time and eventually erupt in the oral cavity. A 15-year-old girl presented with "denticles on the gingiva". During the intraoral examination, seven small tooth-like structures were found. These were exposed in the anterior left gingiva between the permanent maxillary lateral incisor and canine teeth, and the left first premolar was absent. Radiographic examination revealed irregular tooth-like structures without evidence of bone involvement. The lesion was surgically removed, and the specimens were analyzed histopathologically. The diagnosis of compound odontoma was established. This is the twelfth reported case of peripheral odontoma in the gingiva and the first one that erupted in the oral cavity.

  9. Carbon sequestration and eruption hazards

    Science.gov (United States)

    Zhang, Y.

    2007-12-01

    In order to reduce the buildup of carbon dioxide in the atmosphere, proposals have been made to sequestrate carbon in ocean, or in coal mines and other underground formations. High gas concentration in ocean or underground formations has to potential to power gas-driven eruptions. In this presentation, possible eruption hazards are explored. Whenever carbon dioxide is sequestrated in the form of carbon dioxide gas, or dissolved and/or absorbed carbon dioxide, it is necessary to exercise caution to avoid gas-driven eruption hazard. It is long known that explosive volcanic eruptions are driven by H2O gas in magma. Lake eruptions powered by dissolved CO2 in lake bottom water were discovered in the 1980's (Kling et al., 1987; Zhang, 1996). Gas-driven ocean eruptions with mechanism similar to lake eruptions have been hypothesized (Zhang, 2003; Zhang and Kling, 2006) although not confirmed. Mud volcanos are commonly thought to be driven by methane-rich fluids in sediment (Milkov, 2000). Recently, Zhang et al. (2007) have proposed that coal outbursts in underground coal mines are driven by dissolved high CO2 concentration in coal, causing coal fragmentation and outburst. That is, coal outbursts may be regarded as a new type of gas-driven eruptions. Therefore, high concentrations of free gas or dissolved/absorbed gas may power eruptions of magma, lake water, ocean water, sediment, and coal. Gas- driven volcanic, lake and ocean eruptions are due to volume expansion from bubble growth, whereas gas-driven coal and sediment eruptions are due to high gas-pressure, leading to fragmentation of coal and sediment. (In explosive volcanism, magma fragmentation is also a critical point.) The threshold conditions for many of these eruptions are not known yet. In planning large (industrial) scale injection of CO2 into a natural reservoir, it is important to know the eruption threshold and design the injection scheme accordingly. More safe sequestration in terms of eruption hazards would

  10. Schizophrenia with prominent catatonic features: A selective review.

    Science.gov (United States)

    Ungvari, Gabor S; Gerevich, Jozsef; Takács, Rozália; Gazdag, Gábor

    2017-08-14

    A widely accepted consensus holds that a variety of motor symptoms subsumed under the term 'catatonia' have been an integral part of the symptomatology of schizophrenia since 1896, when Kraepelin proposed the concept of dementia praecox (schizophrenia). Until recently, psychiatric classifications included catatonic schizophrenia mainly through tradition, without compelling evidence of its validity as a schizophrenia subtype. This selective review briefly summarizes the history, psychopathology, demographic and epidemiological data, and treatment options for schizophrenia with prominent catatonic features. Although most catatonic signs and symptoms are easy to observe and measure, the lack of conceptual clarity of catatonia and consensus about the threshold and criteria for its diagnosis have hampered our understanding of how catatonia contributes to the pathophysiology of schizophrenic psychoses. Diverse study samples and methodologies have further hindered research on schizophrenia with prominent catatonic features. A focus on the motor aspects of broadly defined schizophrenia using modern methods of detecting and quantifying catatonic signs and symptoms coupled with sophisticated neuroimaging techniques offers a new approach to research in this long-overlooked field. Copyright © 2017. Published by Elsevier B.V.

  11. Toward detailed prominence seismology II. Charting the continuous magnetohydrodynamic spectrum

    NARCIS (Netherlands)

    Blokland, J. W. S.; Keppens, R.

    2011-01-01

    Context. Starting from accurate magnetohydrodynamic flux rope equilibria containing prominence condensations, we initiate a systematic survey of their linear eigenoscillations. This paves the way for more detailed prominence seismology, which thus far has made dramatic simplifications about the

  12. Climatic Impact of Volcanic Eruptions

    Directory of Open Access Journals (Sweden)

    Gregory A. Zielinski

    2002-01-01

    Full Text Available Volcanic eruptions have the potential to force global climate, provided they are explosive enough to emit at least 1–5 megaton of sulfur gases into the stratosphere. The sulfuric acid produced during oxidation of these gases will both absorb and reflect incoming solar radiation, thus warming the stratosphere and cooling the Earth’s surface. Maximum global cooling on the order of 0.2–0.3°C, using instrumental temperature records, occurs in the first 2 years after the eruption, with lesser cooling possibly up to the 4th year. Equatorial eruptions are able to affect global climate, whereas mid- to high-latitude events will impact the hemisphere of origin. However, regional responses may differ, including the possibility of winter warming following certain eruptions. Also, El Niño warming may override the cooling induced by volcanic activity. Evaluation of different style eruptions as well as of multiple eruptions closely spaced in time beyond the instrumental record is attained through the analysis of ice-core, tree-ring, and geologic records. Using these data in conjunction with climate proxy data indicates that multiple eruptions may force climate on decadal time scales, as appears to have occurred during the Little Ice Age (i.e., roughly AD 1400s–1800s. The Toba mega-eruption of ~75,000 years ago may have injected extremely large amounts of material into the stratosphere that remained aloft for up to about 7 years. This scenario could lead to the initiation of feedback mechanisms within the climate system, such as cooling of sea-surface temperatures. These interacting mechanisms following a mega-eruption may cool climate on centennial time scales.

  13. Old World frog and bird vocalizations contain prominent ultrasonic harmonics

    Science.gov (United States)

    Narins, Peter M.; Feng, Albert S.; Lin, Wenyu; Schnitzler, Hans-Ulrich; Denzinger, Annette; Suthers, Roderick A.; Xu, Chunhe

    2004-02-01

    Several groups of mammals such as bats, dolphins and whales are known to produce ultrasonic signals which are used for navigation and hunting by means of echolocation, as well as for communication. In contrast, frogs and birds produce sounds during night- and day-time hours that are audible to humans; their sounds are so pervasive that together with those of insects, they are considered the primary sounds of nature. Here we show that an Old World frog (Amolops tormotus) and an oscine songbird (Abroscopus albogularis) living near noisy streams reliably produce acoustic signals that contain prominent ultrasonic harmonics. Our findings provide the first evidence that anurans and passerines are capable of generating tonal ultrasonic call components and should stimulate the quest for additional ultrasonic species.

  14. Dwarf Star Erupts in Giant Flare

    Science.gov (United States)

    2005-01-01

    This movie taken by NASA'S Galaxy Evolution Explorer shows one of the largest flares, or star eruptions, ever recorded at ultraviolet wavelengths. The star, called GJ 3685A, just happened to be in the Galaxy Evolution Explorer's field of view while the telescope was busy observing galaxies. As the movie demonstrates, the seemingly serene star suddenly exploded once, then even more intensely a second time, pouring out in total about one million times more energy than a typical flare from our Sun. The second blast of light constituted an increase in brightness by a factor of at least 10,000. Flares are huge explosions of energy stemming from a single location on a star's surface. They are caused by the brief destruction of a star's magnetic fields. Many types of stars experience them, though old, small, rapidly rotating 'red dwarfs' like GJ 3685A tend to flare more frequently and dramatically. These stars, called flare stars, can experience powerful eruptions as often as every few hours. Younger stars, in general, also erupt more often. One of the reasons astronomers study flare stars is to gain a better picture and history of flare events taking place on the Sun. A preliminary analysis of the GJ 3685A flare shows that the mechanisms underlying stellar eruptions may be more complex than previously believed. Evidence for the two most popular flare theories was found. Though this movie has been sped up (the actual flare lasted about 20 minutes), time-resolved data exist for each one-hundredth of a second. These observations were taken at 2 p.m. Pacific time, April 24, 2004. In the still image, the time sequence starts in the upper left panel, continues in the upper right, then moves to the lower left and ends in the lower right. The circular and linear features that appear below and to the right of GJ 3685A during the flare event are detector artifacts caused by the extreme brightness of the flare.

  15. Morphology Of A Hot Prominence Cavity Observed with Hinode/XRT and SDO/AIA

    Science.gov (United States)

    Weber, Mark A.; Reeves, K. K.; Gibson, S. E.; Kucera, T. A.

    2012-01-01

    Prominence cavities appear as circularly shaped voids in coronal emission over polarity inversion lines where a prominence channel is straddling the solar limb. The presence of chromospheric material suspended at coronal altitudes is a common but not necessary feature within these cavities. These voids are observed to change shape as a prominence feature rotates around the limb. We use a morphological model projected in cross-sections to fit the cavity emission in Hinode/XRT passbands, and then apply temperature diagnostics to XRT and SDO/AIA data to investigate the thermal structure. We find significant evidence that the prominence cavity is hotter than the corona immediately outside the cavity boundary. This investigation follows upon "Thermal Properties of A Solar Coronal Cavity Observed with the X-ray Telescope on Hinode" by Reeves et al., 2012, ApJ, in press.

  16. Historical Significant Volcanic Eruption Locations

    Data.gov (United States)

    Department of Homeland Security — A significant eruption is classified as one that meets at least one of the following criteriacaused fatalities, caused moderate damage (approximately $1 million or...

  17. Assessing Eruption Column Height in Ancient Flood Basalt Eruptions

    Science.gov (United States)

    Glaze, Lori S.; Self, Stephen; Schmidt, Anja; Hunter, Stephen J.

    2015-01-01

    A buoyant plume model is used to explore the ability of flood basalt eruptions to inject climate-relevant gases into the stratosphere. An example from the 1986 Izu-Oshima basaltic fissure eruption validates the model's ability to reproduce the observed maximum plume heights of 12-16 km above sea level, sustained above fire-fountains. The model predicts maximum plume heights of 13-17 km for source widths of between 4-16 m when 32% (by mass) of the erupted magma is fragmented and involved in the buoyant plume (effective volatile content of 6 wt%). Assuming that the Miocene-age Roza eruption (part of the Columbia River Basalt Group) sustained fire-fountains of similar height to Izu-Oshima (1.6 km above the vent), we show that the Roza eruption could have sustained buoyant ash and gas plumes that extended into the stratosphere at approximately 45 deg N. Assuming 5 km long active fissure segments and 9000 Mt of SO2 released during explosive phases over a 10-15 year duration, the approximately 180 km of known Roza fissure length could have supported approximately 36 explosive events/phases, each with a duration of 3-4 days. Each 5 km fissure segment could have emitted 62 Mt of SO2 per day into the stratosphere while actively fountaining, the equivalent of about three 1991 Mount Pinatubo eruptions per day. Each fissure segment could have had one to several vents, which subsequently produced lava without significant fountaining for a longer period within the decades-long eruption. Sensitivity of plume rise height to ancient atmospheric conditions is explored. Although eruptions in the Deccan Traps (approximately 66 Ma) may have generated buoyant plumes that rose to altitudes in excess of 18 km, they may not have reached the stratosphere because the tropopause was substantially higher in the late Cretaceous. Our results indicate that some flood basalt eruptions, such as Roza, were capable of repeatedly injecting large masses of SO2 into the stratosphere. Thus sustained

  18. Premature dental eruption: report of case.

    LENUS (Irish Health Repository)

    McNamara, C M

    2011-08-05

    This case report reviews the variability of dental eruption and the possible sequelae. Dental eruption of the permanent teeth in cleft palate children may be variable, with delayed eruption the most common phenomenon. A case of premature dental eruption of a maxillary left first premolar is demonstrated, however, in a five-year-old male. This localized premature dental eruption anomaly was attributed to early extraction of the primary dentition, due to caries.

  19. Modeling lunar volcanic eruptions

    Science.gov (United States)

    Housley, R. M.

    1978-01-01

    Simple physical arguments are used to show that basaltic volcanos on different planetary bodies would fountain to the same height if the mole fraction of gas in the magma scaled with the acceleration of gravity. It is suggested that the actual eruption velocities and fountain heights are controlled by the velocities of sound in the two phase gas/liquid flows. These velocities are in turn determined by the gas contents in the magma. Predicted characteristics of Hawaiian volcanos are in excellent accord with observations. Assuming that the only gas in lunar volcano is the CO which would be produced if the observed Fe metal in lunar basalts resulted from graphite reduction, lunar volcanos would fountain vigorously, but not as spectacularly as their terrestrial counterparts. The volatile trace metals, halogens, and sulfur released would be transported over the entire moon by the transient atmosphere. Orange and black glass type pyroclastic materials would be transported in sufficient amounts to produce the observed dark mantle deposits.

  20. Eruptive history of the Ubehebe Crater cluster, Death Valley, California

    Science.gov (United States)

    Fierstein, Judy; Hildreth, Wes

    2017-04-01

    A sequence of late Holocene eruptions from the Ubehebe Crater cluster in Death Valley was short-lived, emplacing several phreatomagmatic and magmatic deposits. Seven craters form the main group, which erupted along a north-south alignment 1.5 km long. At least five more make a 500-m east-west alignment west of the main crater group. One more is an isolated shallow crater 400 m south of that alignment. All erupted through Miocene fanglomerate and sandstone, which are now distributed as comminuted matrix and lithic clasts in all Ubehebe deposits. Stratigraphic evidence showing that all Ubehebe strata were emplaced within a short time interval includes: (1) deposits from the many Ubehebe vents make a multi-package sequence that conformably drapes paleo-basement topography with no erosive gullying between emplacement units; (2) several crater rims that formed early in the eruptive sequence are draped smoothly by subsequent deposits; and (3) tack-welded to agglutinated spatter and bombs that erupted at various times through the sequence remained hot enough to oxidize the overlying youngest emplacement package. In addition, all deposits sufficiently consolidated to be drilled yield reliable paleomagnetic directions, with site mean directions showing no evidence of geomagnetic secular variation. Chemical analyses of juvenile components representing every eruptive package yield a narrow range in major elements [SiO2 (48.65-50.11); MgO (4.98-6.23); K2O (2.24-2.39)] and trace elements [Rb (28-33); Sr (1513-1588); Zr (373-404)]. Despite lithologic similarities, individual fall units can be traced outward from vent by recording layer thicknesses, maximum scoria and lithic sizes, and juvenile clast textural variations. This permits reconstruction of the eruptive sequence, which produced a variety of eruptive styles. The largest and northernmost of the craters, Ubehebe Crater, is the youngest of the group. Its largely phreatomagmatic deposits drape all of the others, thicken in

  1. Evident?

    DEFF Research Database (Denmark)

    Plant, Peter

    2012-01-01

    Quality assurance and evidence in career guidance in Europe are often seen as self-evident approaches, but particular interests lie behind......Quality assurance and evidence in career guidance in Europe are often seen as self-evident approaches, but particular interests lie behind...

  2. Analysis of extreme-ultraviolet spectroheliograms of solar prominences

    Science.gov (United States)

    Kanno, M.; Withbroe, G. L.; Noyes, R. W.

    1981-01-01

    The optical depth at the head of the Lyman continuum, tau sub H, was determined at several positions in three hedgerow prominences using spectroheliograms of C III 977 A, LC 896 A, and O IV 554 A, observed with the Harvard experiment on Skylab. It is found that tau sub H varies over a wide range at positions even in a single prominence. At the central part of the prominences where the opacity is largest, tau sub H reaches a maximum value of 30 to 50 for the three prominences. In general, tau sub H decreases with height in the prominences. Most positions near the outer boundary of the prominences are optically thin in the LC (tau sub H less than 1). The determination of tau sub H for P23 is consistent with the data of the Mg X spectroheliograms

  3. Case report: pre-eruptive intra-coronal radiolucencies revisited.

    LENUS (Irish Health Repository)

    Counihan, K P

    2012-08-01

    Pre-eruptive intra-coronal radiolucency (PEIR) describes a radiolucent lesion located in the coronal dentine, just beneath the enamel-dentine junction of unerupted teeth. The prevalence of this lesion varies depending on the type and quality of radiographic exposure and age of patients used for assessment. The aetiology of pre-eruptive intra-coronal radiolucent lesions is not fully understood, but published clinical and histological evidence suggest that these lesions are resorptive in nature. Issues around the diagnosis, treatment planning and clinical management of this lesion are explored using previously unreported cases.

  4. Kamchatkan Volcanic Eruption Response Team (KVERT), Russia: preventing the danger of volcanic eruptions to aviation.

    Science.gov (United States)

    Girina, O.; Neal, Ch.

    2012-04-01

    The Kamchatkan Volcanic Eruption Response Team (KVERT) has been a collaborative project of scientists from the Institute of Volcanology and Seismology, the Kamchatka Branch of Geophysical Surveys, and the Alaska Volcano Observatory (IVS, KB GS and AVO). The purpose of KVERT is to reduce the risk of costly, damaging, and possibly deadly encounters of aircraft with volcanic ash clouds. To reduce this risk, KVERT collects all possible volcanic information and issues eruption alerts to aviation and other emergency officials. KVERT was founded by Institute of Volcanic Geology and Geochemistry FED RAS in 1993 (in 2004, IVGG merged with the Institute of Volcanology to become IVS). KVERT analyzes volcano monitoring data (seismic, satellite, visual and video, and pilot reports), assigns the Aviation Color Code, and issues reports on eruptive activity and unrest at Kamchatkan (since 1993) and Northern Kurile (since 2003) volcanoes. KVERT receives seismic monitoring data from KB GS (the Laboratory for Seismic and Volcanic Activity). KB GS maintains telemetered seismic stations to investigate 11 of the most active volcanoes in Kamchatka. Data are received around the clock and analysts evaluate data each day for every monitored volcano. Satellite data are provided from several sources to KVERT. AVO conducts satellite analysis of the Kuriles, Kamchatka, and Alaska as part of it daily monitoring and sends the interpretation to KVERT staff. KVERT interprets MODIS and MTSAT images and processes AVHRR data to look for evidence of volcanic ash and thermal anomalies. KVERT obtains visual volcanic information from volcanologist's field trips, web-cameras that monitor Klyuchevskoy (established in 2000), Sheveluch (2002), Bezymianny (2003), Koryaksky (2009), Avachinsky (2009), Kizimen (2011), and Gorely (2011) volcanoes, and pilots. KVERT staff work closely with staff of AVO, AMC (Airport Meteorological Center) at Yelizovo Airport and the Tokyo Volcanic Ash Advisory Center (VAAC), the

  5. Imaging Observations of Magnetic Reconnection in a Solar Eruptive Flare

    International Nuclear Information System (INIS)

    Li, Y.; Ding, M. D.; Sun, X.; Qiu, J.; Priest, E. R.

    2017-01-01

    Solar flares are among the most energetic events in the solar atmosphere. It is widely accepted that flares are powered by magnetic reconnection in the corona. An eruptive flare is usually accompanied by a coronal mass ejection, both of which are probably driven by the eruption of a magnetic flux rope (MFR). Here we report an eruptive flare on 2016 March 23 observed by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory . The extreme-ultraviolet imaging observations exhibit the clear rise and eruption of an MFR. In particular, the observations reveal solid evidence of magnetic reconnection from both the corona and chromosphere during the flare. Moreover, weak reconnection is observed before the start of the flare. We find that the preflare weak reconnection is of tether-cutting type and helps the MFR to rise slowly. Induced by a further rise of the MFR, strong reconnection occurs in the rise phases of the flare, which is temporally related to the MFR eruption. We also find that the magnetic reconnection is more of 3D-type in the early phase, as manifested in a strong-to-weak shear transition in flare loops, and becomes more 2D-like in the later phase, as shown by the apparent rising motion of an arcade of flare loops.

  6. Imaging Observations of Magnetic Reconnection in a Solar Eruptive Flare

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.; Ding, M. D. [School of Astronomy and Space Science, Nanjing University, Nanjing 210023 (China); Sun, X. [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States); Qiu, J. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Priest, E. R., E-mail: yingli@nju.edu.cn [School of Mathematics and Statistics, University of St Andrews, Fife KY16 9SS, Scotland (United Kingdom)

    2017-02-01

    Solar flares are among the most energetic events in the solar atmosphere. It is widely accepted that flares are powered by magnetic reconnection in the corona. An eruptive flare is usually accompanied by a coronal mass ejection, both of which are probably driven by the eruption of a magnetic flux rope (MFR). Here we report an eruptive flare on 2016 March 23 observed by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory . The extreme-ultraviolet imaging observations exhibit the clear rise and eruption of an MFR. In particular, the observations reveal solid evidence of magnetic reconnection from both the corona and chromosphere during the flare. Moreover, weak reconnection is observed before the start of the flare. We find that the preflare weak reconnection is of tether-cutting type and helps the MFR to rise slowly. Induced by a further rise of the MFR, strong reconnection occurs in the rise phases of the flare, which is temporally related to the MFR eruption. We also find that the magnetic reconnection is more of 3D-type in the early phase, as manifested in a strong-to-weak shear transition in flare loops, and becomes more 2D-like in the later phase, as shown by the apparent rising motion of an arcade of flare loops.

  7. Widespread bullous fixed drug eruption.

    Science.gov (United States)

    Patell, Rushad D; Dosi, Rupal V; Shah, Purav C; Joshi, Harshal S

    2014-02-07

    A 53-year-old man developed a widespread erythematous eruption which rapidly evolved into fluid-filled bulla mostly involving the distal areas of all four limbs and erosions on the oral as well as anogenital mucosa. Based on clinical presentation, chronology of drug exposure, past events and histopathology as diagnosis of widespread bullous fixed drug eruption was made over Steven Johnson-toxic epidermal necrolysis syndrome. Steroids were deferred and the lesions healed with minimal pigmentation within a week. Differentiating between the two entities has been historically difficult, and yet can have significant therapeutic and prognostic implications.

  8. Io - One of at Least Four Simultaneous Erupting Volcanic Eruptions

    Science.gov (United States)

    1979-01-01

    This photo of an active volcanic eruption on Jupiter's satellite Io was taken 1 hour, 52 minutes after the accompanying picture, late in the evening of March 4, 1979, Pacific time. On the limb of the satellite can be seen one of at least four simultaneous volcanic eruptions -- the first such activity ever observed on another celestial body. Seen against the limb are plume-like structures rising more than 60 miles (100 kilometers) above the surface. Several eruptions have been identified with volcanic structures on the surface of Io, which have also been identified by Voyager 1's infrared instrument as being abnormally hot -- several hundred degrees warmer than surrounding terrain. The fact that several eruptions appear to be occurring at the same time suggests that Io has the most active surface in the solar system and that volcanism is going on there essentially continuously. Another characteristic of the observed volcanism is that it appears to be extremely explosive, with velocities more than 2,000 miles an hour (at least 1 kilometer per second). That is more violent than terrestrial volcanoes like Etna, Vesuvius or Krakatoa.

  9. Thermal Properties of Prominence Motions as Observed in the UV

    Science.gov (United States)

    Kucera, T.; Landi, E.

    2003-01-01

    The mechanisms by which solar prominences are filled with plasma are still undetermined. In this study we perform a quantitative analysis of the thermal properties of moving features in prominences in order to put constraints on models of prominence formation and dynamics. In order to make such measurements of quickly moving features seen in prominences in the UV we use the SOHO instruments SUMER and CDS to take a time series of exposures at a single pointing position, providing a measurement of spectral line properties as a function of time and position along the slit. The resulting observations in spectral lines in a range of 'transition region' temperatures allow us to analyze the thermal properties of the moving prominence sources as a function of time.

  10. Combined surgical management of mandibular angle prominence and microgenia

    International Nuclear Information System (INIS)

    Portelles Masso, Ayelen Maria; Berger Kohn, Carlos

    2010-01-01

    Chin play a very important role in facial aesthetics. Different deformities of volume and of position may occur at this level and it is the microgenia one of the more frequent. Treatment options include the use of silicone, alloplasty materials and autologous bone graft. Authors report the use of the bone removed from mandibular angle to increase the chin. This is the case of a white female patient aged 18 seen by the Orthognathics Multidisciplinary Staff of 'V. I. Lenin' Hospital due to its uncommon face width. The corresponding physical examination as well as the complementary ones diagnosed a bilateral prominence of mandibular angle associated with a microgenia. Surgery carried out was of remodeling type of both mandibular angles and genioplasty of height increase and a discrete advancement using the bone removed from the gonion. There were satisfactory aesthetic results without evidence of bone reabsorption. We conclude that use of autologous graft of mandibular angle is an effective treatment alternative for correction of microgenia. (author)

  11. A study of a coronal hole associated with a large filament eruption

    Science.gov (United States)

    Gutiérrez, Heidy; Taliashvili, Lela; Lazarian, Alexandre; Mouradian, Zadig

    2017-11-01

    We report the results of a detailed study of an equatorial coronal hole and a dimming region related to the eruptions of a nearby large filament and subsequent coronal mass ejections (CMEs). The dynamic eruptions of the filament and the associated CMEs are probably related to the magnetic reconnection involving the magnetic field lines at the filament footpoints. During the starting processes of the filament eruption, we observed several newly emerged small magnetic flux concentrations close to the filament footpoints. Disturbance increase in the prominence body was observed during the pre-eruption processes. After the filament eruption, we observed evacuated filament material from the filament channel towards the coronal hole. Thus, all the region is perturbed and EUV loops and bright points are observed before and after the eruptions. Additionally, after the CME, we observed the disappearance of the dimming region and the coronal hole, followed by photospheric magnetic diffusion. We discussed a possible magnetic reconnection scenario and MHD waves involved during these processes.

  12. Eruption cysts: A series of two cases

    OpenAIRE

    Dhawan, Preeti; Kochhar, Gulsheen Kaur; Chachra, Sanjay; Advani, Shweta

    2012-01-01

    Eruption cysts are benign cysts that appear on the mucosa of a tooth shortly before its eruption. They may disappear by themselves but if they hurt, bleed or are infected they may require surgical treatment to expose the tooth and drain the contents. Here we present 2 case reports of eruption cysts presenting with different chief complaint. The treatment included incising the eruption cyst and draining the contents of the cyst.

  13. IMAGING A MAGNETIC-BREAKOUT SOLAR ERUPTION

    International Nuclear Information System (INIS)

    Chen, Yao; Du, Guohui; Zhao, Di; Wu, Zhao; Wang, Bing; Ruan, Guiping; Feng, Shiwei; Song, Hongqiang; Liu, Wei

    2016-01-01

    The fundamental mechanism initiating coronal mass ejections (CMEs) remains controversial. One of the leading theories is magnetic breakout, in which magnetic reconnection occurring high in the corona removes the confinement on an energized low-corona structure from the overlying magnetic field, thus allowing it to erupt. Here, we report critical observational evidence of this elusive breakout reconnection in a multi-polar magnetic configuration that leads to a CME and an X-class, long-duration flare. Its occurrence is supported by the presence of pairs of heated cusp-shaped loops around an X-type null point and signatures of reconnection inflows. Other peculiar features new to the breakout picture include sequential loop brightening, coronal hard X-rays at energies up to ∼100 keV, and extended high-corona X-rays above the later restored multi-polar structure. These observations, from a novel perspective with clarity never achieved before, present crucial clues to understanding the initiation mechanism of solar eruptions

  14. Imaging a Magnetic-breakout Solar Eruption

    Science.gov (United States)

    Chen, Yao; Du, Guohui; Zhao, Di; Wu, Zhao; Liu, Wei; Wang, Bing; Ruan, Guiping; Feng, Shiwei; Song, Hongqiang

    2016-04-01

    The fundamental mechanism initiating coronal mass ejections (CMEs) remains controversial. One of the leading theories is magnetic breakout, in which magnetic reconnection occurring high in the corona removes the confinement on an energized low-corona structure from the overlying magnetic field, thus allowing it to erupt. Here, we report critical observational evidence of this elusive breakout reconnection in a multi-polar magnetic configuration that leads to a CME and an X-class, long-duration flare. Its occurrence is supported by the presence of pairs of heated cusp-shaped loops around an X-type null point and signatures of reconnection inflows. Other peculiar features new to the breakout picture include sequential loop brightening, coronal hard X-rays at energies up to ˜100 keV, and extended high-corona X-rays above the later restored multi-polar structure. These observations, from a novel perspective with clarity never achieved before, present crucial clues to understanding the initiation mechanism of solar eruptions.

  15. Crust-ocean interactions during midocean ridge eruptions

    Science.gov (United States)

    Baker, E. T.

    2011-12-01

    Eruptions are the "quantum event" of crustal accretion, occurring daily to monthly (depending on spreading rate) along the global midocean ridge system. The number of eruptions detected and responded to remain very few, however, so our knowledge of the magnitude and rate of crust-ocean interaction at the instant of an eruption is almost entirely circumstantial. The discovery of uniquely different plumes over a 2008 eruption on the NE Lau spreading center greatly broadened the known range of eruption-initiated transfer of heat, chemicals, and perhaps biota from the crust to the ocean. Serendipitous observations and rapid response cruises have now documented that the "event (mega-) plumes" accompanying eruptions range over a factor of 100 in volume (1-150 km3), yet maintain a distinctive and consistent chemical signature (much lower 3He/heat and Mn/heat and higher H2/heat than typical black smokers). Confirmed event plumes have formed at spreading rates from 55-~90 mm/yr, with some incompletely sampled but "event-like" plumes observed at even slower rates (11-30 mm/yr; Gakkel and Carlsberg Ridges). Presently, only four event plumes can be associated with specific eruptions. Large event plumes in the NE Pacific were found over thick (up to ~75 m), voluminous, and slowly extruded pillow mounds. The 2008 eruption on the fast-spreading NE Lau spreading center demonstrated that thin (a few meters), small, and rapidly emplaced sheet flows can generate smaller event plumes. Available evidence suggests that massive fluid discharge occurs virtually simultaneously with an eruption. At Gorda Ridge in 1996, eruption-indicative seismicity began on the same day and location an event plume was found. At Axial Volcano in 1998, moorings 2 km apart both recorded the appearance of a >100-m-thick plume within minutes of the start of a 72-min-long sheet flow eruption. These observations support inferences from plume modeling and chemistry that event plume generation time is hours, not

  16. ON THE RELATIONSHIP BETWEEN A HOT-CHANNEL-LIKE SOLAR MAGNETIC FLUX ROPE AND ITS EMBEDDED PROMINENCE

    International Nuclear Information System (INIS)

    Cheng, X.; Ding, M. D.; Zhang, J.; Guo, Y.; Chen, P. F.; Sun, J. Q.; Srivastava, A. K.

    2014-01-01

    A magnetic flux rope (MFR) is a coherent and helical magnetic field structure that has recently been found likely to appear as an elongated hot channel prior to a solar eruption. In this Letter, we investigate the relationship between the hot channel and the associated prominence through analysis of a limb event on 2011 September 12. In the early rise phase, the hot channel was initially cospatial with the prominence. It then quickly expanded, resulting in a separation of the top of the hot channel from that of the prominence. Meanwhile, they both experienced an instantaneous morphology transformation from a Λ shape to a reversed-Y shape and the top of these two structures showed an exponential increase in height. These features are a good indication of the occurrence of kink instability. Moreover, the onset of kink instability is found to coincide in time with the impulsive enhancement of flare emission underneath the hot channel, suggesting that ideal kink instability likely also plays an important role in triggering fast flare reconnection besides initiating the impulsive acceleration of the hot channel and distorting its morphology. We conclude that the hot channel is most likely the MFR system and the prominence only corresponds to the cool materials that are collected in the bottom of the helical field lines of the MFR against gravity

  17. The Run-up to Volcanic Eruption Unveiled by Forensic Petrology and Geophysical Observations

    Science.gov (United States)

    Rasmussen, D. J.; Plank, T. A.; Roman, D. C.

    2017-12-01

    Volcanoes often warn of impending eruptions. However, one of the greatest challenges in volcano research is translating precursory geophysical signals into physical magmatic processes. Petrology offers powerful tools to study eruption run-up that benefit from direct response to magmatic forcings. Developing these tools, and tying them to geophysical observations, will help us identify eruption triggers (e.g., magmatic recharge, gas build-up, tectonic events) and understand the significance of monitored signals of unrest. We present an overview of petrologic tools used for studying eruption run-up, highlighting results from our study of the 1999 eruption of Shishaldin volcano. Olivine crystals contain chemical gradients, the consequence of diffusion following magma mixing events, which is modeled to determine mixing timescales. Modeled timescales provide strong evidence for at least three mixing events, which were triggered by magmatic recharge. Petrologic barometers indicate these events occurred at very shallow depths (within the volcanic edifice). The first mixing event occurred nine months before eruption, which was signaled by a swarm of deep-long period earthquake. Minor recharge events followed over two months, which are indicated by a second deep-long period earthquake swarm and a change in the local stress orientation measured by shear-wave splitting. Following these events, the system was relatively quiet until a large mixing event occurred 45 days prior to eruption, which was heralded by a large earthquake (M5.2). Following this event, geophysical signals of unrest intensified and became continuous. The final mixing event, beginning roughly a week before eruption, represents the final perturbation to the system before eruption. Our findings point to a relatively long run-up, which was subtle at first and intensified several weeks before eruption. This study highlights the strong link between geophysical signals of volcanic unrest and magmatic events, and

  18. ARE TORNADO-LIKE MAGNETIC STRUCTURES ABLE TO SUPPORT SOLAR PROMINENCE PLASMA?

    International Nuclear Information System (INIS)

    Luna, M.; Moreno-Insertis, F.; Priest, E.

    2015-01-01

    Recent high-resolution and high-cadence observations have surprisingly suggested that prominence barbs exhibit apparent rotating motions suggestive of a tornado-like structure. Additional evidence has been provided by Doppler measurements. The observations reveal opposite velocities for both hot and cool plasma on the two sides of a prominence barb. This motion is persistent for several hours and has been interpreted in terms of rotational motion of prominence feet. Several authors suggest that such barb motions are rotating helical structures around a vertical axis similar to tornadoes on Earth. One of the difficulties of such a proposal is how to support cool prominence plasma in almost-vertical structures against gravity. In this work we model analytically a tornado-like structure and try to determine possible mechanisms to support the prominence plasma. We have found that the Lorentz force can indeed support the barb plasma provided the magnetic structure is sufficiently twisted and/or significant poloidal flows are present

  19. ARE TORNADO-LIKE MAGNETIC STRUCTURES ABLE TO SUPPORT SOLAR PROMINENCE PLASMA?

    Energy Technology Data Exchange (ETDEWEB)

    Luna, M.; Moreno-Insertis, F. [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain); Priest, E. [Mathematics Institute, University of St Andrews, St Andrews KY16 9SS (United Kingdom)

    2015-07-20

    Recent high-resolution and high-cadence observations have surprisingly suggested that prominence barbs exhibit apparent rotating motions suggestive of a tornado-like structure. Additional evidence has been provided by Doppler measurements. The observations reveal opposite velocities for both hot and cool plasma on the two sides of a prominence barb. This motion is persistent for several hours and has been interpreted in terms of rotational motion of prominence feet. Several authors suggest that such barb motions are rotating helical structures around a vertical axis similar to tornadoes on Earth. One of the difficulties of such a proposal is how to support cool prominence plasma in almost-vertical structures against gravity. In this work we model analytically a tornado-like structure and try to determine possible mechanisms to support the prominence plasma. We have found that the Lorentz force can indeed support the barb plasma provided the magnetic structure is sufficiently twisted and/or significant poloidal flows are present.

  20. Are Tornado-Like Magnetic Structures Able to Support Solar Prominence Plasma?

    Science.gov (United States)

    Ogunjo, S. T.; Luna Bennasar, M.; Moreno-Insertis, F.; Priest, E. R.

    2015-12-01

    Recent high-resolution and high-cadence observations have surprisingly suggested that prominence barbs exhibit apparent rotating motions suggestive of a tornado-like structure. Additional evidence has been provided by Doppler measurements. The observations reveal opposite velocities for both hot and cool plasma on the two sides of a prominence barb. This motion is persistent for several hours and has been interpreted in terms of rotational motion of prominence feet. Several authors suggest that such barb motions are rotating helical structures around a vertical axis similar to tornadoes on Earth. One of the difficulties of such a proposal is how to support cool prominence plasma in almost-vertical structures against gravity. In this work we model analytically a tornado-like structure and try to determine possible mechanisms to support the prominence plasma. We have found that the Lorentz force can indeed support the barb plasma provided the magnetic structure is sufficiently twisted and/or significant poloidal flows are present.

  1. Regional early development and eruption of permanent teeth: case report.

    Science.gov (United States)

    Al Mullahi, A M; Bakathir, A; Al Jahdhami, S

    2017-02-01

    Early development and eruption of permanent teeth are rarely reported in scientific literature. Early eruption of permanent teeth has been reported to occur due to local factors such as trauma or dental abscesses in primary teeth, and in systemic conditions. Congenital diffuse infiltrating facial lipomatosis (CDIFL) is a rare condition that belongs to a group of lipomatosis tumours. In this disorder, the mature adipocytes invade adjacent soft and hard tissues in the facial region. Accelerated tooth eruption is one of the dental anomalies associated with CDIFL. A 3-year-old boy presented with a swelling of the lower lip localised early development and eruption of permanent teeth and dental caries involving many primary teeth. The planned treatment included biopsy of the swollen lower lip to confirm the diagnosis, surgical reduction and reconstruction of lip aesthetics. The management of the carious primary teeth included preventative and comprehensive dental care and extractions. These procedures were completed under general anaesthesia due to the child's young age and poor cooperation. The lip biopsy showed features of CDIFL such as the presence of infiltrating adipose tissue, prominent number of nerve bundles and thickened vessels. The high recurrence rate of CDIFL mandates long-term monitoring during the facial growth period of the child. Follow-up care by the paediatric dentist and maxillofacial surgeon has been required to manage all aspects of this congenital malformation. This rare disorder has many implications affecting child's facial aesthetics, psychological well being, developing occlusion and risk of dental caries. A multi-disciplinary approach is needed for management of this condition.

  2. Transient changes in bacterioplankton communities induced by the submarine volcanic eruption of El Hierro (Canary Islands.

    Directory of Open Access Journals (Sweden)

    Isabel Ferrera

    Full Text Available The submarine volcanic eruption occurring near El Hierro (Canary Islands in October 2011 provided a unique opportunity to determine the effects of such events on the microbial populations of the surrounding waters. The birth of a new underwater volcano produced a large plume of vent material detectable from space that led to abrupt changes in the physical-chemical properties of the water column. We combined flow cytometry and 454-pyrosequencing of 16S rRNA gene amplicons (V1-V3 regions for Bacteria and V3-V5 for Archaea to monitor the area around the volcano through the eruptive and post-eruptive phases (November 2011 to April 2012. Flow cytometric analyses revealed higher abundance and relative activity (expressed as a percentage of high-nucleic acid content cells of heterotrophic prokaryotes during the eruptive process as compared to post-eruptive stages. Changes observed in populations detectable by flow cytometry were more evident at depths closer to the volcano (~70-200 m, coinciding also with oxygen depletion. Alpha-diversity analyses revealed that species richness (Chao1 index decreased during the eruptive phase; however, no dramatic changes in community composition were observed. The most abundant taxa during the eruptive phase were similar to those in the post-eruptive stages and to those typically prevalent in oceanic bacterioplankton communities (i.e. the alphaproteobacterial SAR11 group, the Flavobacteriia class of the Bacteroidetes and certain groups of Gammaproteobacteria. Yet, although at low abundance, we also detected the presence of taxa not typically found in bacterioplankton communities such as the Epsilonproteobacteria and members of the candidate division ZB3, particularly during the eruptive stage. These groups are often associated with deep-sea hydrothermal vents or sulfur-rich springs. Both cytometric and sequence analyses showed that once the eruption ceased, evidences of the volcano-induced changes were no longer

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

    Science.gov (United States)

    Nomikou, Paraskevi; Druitt, Tim; Hübscher, Christian; Mather, Tamsin; Paulatto, Michele; Kalnins, Lara; Kelfoun, Karim; Papanikolaou, Dimitris; Bejelou, Konstantina; Lampridou, Danai; Pyle, David; Carey, Steven; Watts, Anthony; Weiß, Benedikt; Parks, Michelle

    2017-04-01

    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 eruption of Santorini 3600 years ago was one of the largest of eruptions known worldwide from the past 10,000 years - and was at least 3 times larger than the catastrophic eruption of Krakatoa. This huge eruption evacuated large volumes of magma, causing collapse of the large caldera, which is now filled with seawater. Tsunamis from this eruption have been proposed to have played a role in the demise of the Minoan culture across the southern Aegean, through damage to coastal towns, harbors, shipping and maritime trade. Before the eruption, there was an older caldera in the northern part of Santorini, partly filled with a shallow lagoon. In our study, 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. Following subsidence of the caldera floor, rapid inflow of seawater and landslides cut a deep 2.0-2.5 km3 submarine channel into the northern flank of the caldera wall. Hydrodynamic modelling indicates that the caldera was flooded through this breach in less than a couple of days. It was previously proposed that collapse of the caldera could have led to the formation of a major tsunami; but this is ruled out by our new evidence. Any tsunami's generated were most likely caused by entry of pyroclastic flows into the sea, combined with slumping of submarine pyroclastic accumulations. This idea is consistent with previous assertions that pyroclastic flows were the main cause of tsunamis at Krakatau.

  4. Simultaneous Observations of Solar Prominence Oscillations Using Two Remote Telescopes

    Czech Academy of Sciences Publication Activity Database

    Zapiór, M.; Kotrč, Pavel; Rudawy, P.; Oliver, R.

    2015-01-01

    Roč. 290, č. 6 (2015), s. 1647-1659 ISSN 0038-0938 Institutional support: RVO:67985815 Keywords : optical observations * prominences * oscillations Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.862, year: 2015

  5. Two-step solar filament eruptions

    Science.gov (United States)

    Filippov, B.

    2018-04-01

    Coronal mass ejections (CMEs) are closely related to eruptive filaments and usually are the continuation of the same eruptive process into the upper corona. There are failed filament eruptions when a filament decelerates and stops at some greater height in the corona. Sometimes the filament after several hours starts to rise again and develops into the successful eruption with a CME formation. We propose a simple model for the interpretation of such two-step eruptions in terms of equilibrium of a flux rope in a two-scale ambient magnetic field. The eruption is caused by a slow decrease of the holding magnetic field. The presence of two critical heights for the initiation of the flux-rope vertical instability allows the flux rope to stay after the first jump some time in a metastable equilibrium near the second critical height. If the decrease of the ambient field continues, the next eruption step follows.

  6. Toward detailed prominence seismology - II. Charting the continuous magnetohydrodynamic spectrum

    OpenAIRE

    Blokland, J. W. S.; Keppens, R.

    2011-01-01

    Context. Starting from accurate magnetohydrodynamic flux rope equilibria containing prominence condensations, we initiate a systematic survey of their linear eigenoscillations. This paves the way for more detailed prominence seismology, which thus far has made dramatic simplifications about the prevailing magnetic field topologies. Aims. To quantify the full spectrum of linear MHD eigenmodes, we require knowledge of all flux-surface localized modes, charting out the continuous parts of the MH...

  7. Prominence Bubble Shear Flows and the Coupled Kelvin-Helmholtz — Rayleigh-Taylor Instability

    Science.gov (United States)

    Berger, Thomas; Hillier, Andrew

    2017-08-01

    Prominence bubbles are large arched structures that rise from below into quiescent prominences, often growing to heights on the order of 10 Mm before going unstable and generating plume upflows. While there is general agreement that emerging flux below pre-existing prominences causes the structures, there is lack of agreement on the nature of the bubbles and the cause of the instability flows. One hypothesis is that the bubbles contain coronal temperature plasma and rise into the prominence above due to both magnetic and thermal buoyancy, eventually breaking down via a magnetic Rayleigh-Taylor (RT) instability to release hot plasma and magnetic flux and helicity into the overlying coronal flux rope. Another posits that the bubbles are actually just “arcades” in the prominence indicating a magnetic separator line between the bipole and the prominence fields with the observed upflows and downflows caused by reconnection along the separator. We analyze Hinode/SOT, SDO/AIA, and IRIS observations of prominence bubbles, focusing on characteristics of the bubble boundary layers that may discriminate between the two hypotheses. We find speeds on the order of 10 km/s in prominence plasma downflows and lateral shear flows along the bubble boundary. Inflows to the boundary gradually increase the thickness and brightness of the layer until plasma drains from there, apparently around the dome-like bubble domain. In one case, shear flow across the bubble boundary develops Kelvin-Helmholtz (KH) vortices that we use to infer flow speeds in the low-density bubble on the order of 100 km/sec. IRIS spectra indicate that plasma flows on the bubble boundary at transition region temperatures achieve Doppler speeds on the order of 50 km/s, consistent with this inference. Combined magnetic KH-RT instability analysis leads to flux density estimates of 10 G with a field angle of 30° to the prominence, consistent with vector magnetic field measurements. In contrast, we find no evidence

  8. Ghost Remains After Black Hole Eruption

    Science.gov (United States)

    2009-05-01

    NASA's Chandra X-ray Observatory has found a cosmic "ghost" lurking around a distant supermassive black hole. This is the first detection of such a high-energy apparition, and scientists think it is evidence of a huge eruption produced by the black hole. This discovery presents astronomers with a valuable opportunity to observe phenomena that occurred when the Universe was very young. The X-ray ghost, so-called because a diffuse X-ray source has remained after other radiation from the outburst has died away, is in the Chandra Deep Field-North, one of the deepest X-ray images ever taken. The source, a.k.a. HDF 130, is over 10 billion light years away and existed at a time 3 billion years after the Big Bang, when galaxies and black holes were forming at a high rate. "We'd seen this fuzzy object a few years ago, but didn't realize until now that we were seeing a ghost", said Andy Fabian of the Cambridge University in the United Kingdom. "It's not out there to haunt us, rather it's telling us something - in this case what was happening in this galaxy billions of year ago." Fabian and colleagues think the X-ray glow from HDF 130 is evidence for a powerful outburst from its central black hole in the form of jets of energetic particles traveling at almost the speed of light. When the eruption was ongoing, it produced prodigious amounts of radio and X-radiation, but after several million years, the radio signal faded from view as the electrons radiated away their energy. HDF 130 Chandra X-ray Image of HDF 130 However, less energetic electrons can still produce X-rays by interacting with the pervasive sea of photons remaining from the Big Bang - the cosmic background radiation. Collisions between these electrons and the background photons can impart enough energy to the photons to boost them into the X-ray energy band. This process produces an extended X-ray source that lasts for another 30 million years or so. "This ghost tells us about the black hole's eruption long after

  9. Predicting eruptions at mount st. Helens, june 1980 through december 1982.

    Science.gov (United States)

    Swanson, D A; Casadevall, T J; Dzurisin, D; Malone, S D; Newhall, C G; Weaver, C S

    1983-09-30

    Thirteen eruptions of Mount St. Helens between June 1980 and December 1982 were predicted tens of minutes to, more generally, a few hours in advance. The last seven of these eruptions, starting with that of mid-April 1981, were predicted between 3 days and 3 weeks in advance. Precursory seismicity, deformation of the crater floor and the lava dome, and, to a lesser extent, gas emissions provided telltale evidence of forthcoming eruptions. The newly developed capability for prediction reduced risk to life and property and influenced land-use decisions.

  10. Tooth eruption and browridge formation.

    Science.gov (United States)

    Russell, M D

    1982-05-01

    One of the most reasonable hypotheses regarding the functional significance of the browridge is that the supraorbital torus forms in response to masticatory stress during development. Oyen, Walker, and Rice (1979) have recently proposed a model that tests this hypothesis: if browridges are functionally related to masticatory stresses on the cranial vault, then changes in the biomechanics of the masticatory system ought to be reflected by changes in the browridge. To test their model they attempted to relate biomechanical discontinuities resulting from tooth eruption to episodes of bone deposition on the supraorbital tori of a developmental series of dry Papio crania. This paper reports on a parallel test of the model on a cross-sectional sample of Australian Aboriginal juvenile crania. This sample showed no relation between tooth eruption and the supraorbital surface morphology thought to be indicative of active bone deposition. It is also demonstrated that no significant relationship between tooth eruption and episodes of bone deposition is shown by the Papio sample. It is concluded that the use of small cross-sectional samples of dry crania does not provide a valid test of the model.

  11. Small volcanic eruptions and the stratospheric sulfate aerosol burden

    Science.gov (United States)

    Pyle, David M.

    2012-09-01

    Understanding of volcanic activity and its impacts on the atmosphere has evolved in discrete steps, associated with defining eruptions. The eruption of Krakatau, Indonesia, in August 1883 was the first whose global reach was recorded through observations of atmospheric phenomena around the world (Symons 1888). The rapid equatorial spread of Krakatau's ash cloud revealed new details of atmospheric circulation, while the vivid twilights and other optical phenomena were soon causally linked to the effects of particles and gases released from the volcano (e.g. Stothers 1996, Schroder 1999, Hamilton 2012). Later, eruptions of Agung, Bali (1963), El Chichón, Mexico (1982) and Pinatubo, Philippines (1991) led to a fuller understanding of how volcanic SO2 is transformed to a long-lived stratospheric sulfate aerosol, and its consequences (e.g. Meinel and Meinel 1967, Rampino and Self 1982, Hoffman and Rosen 1983, Bekki and Pyle 1994, McCormick et al 1995). While our ability to track the dispersal of volcanic emissions has been transformed since Pinatubo, with the launch of fleets of Earth-observing satellites (e.g. NASA's A-Train; ESA's MetOp) and burgeoning networks of ground-based remote-sensing instruments (e.g. lidar and sun-photometers; infrasound and lightning detection systems), there have been relatively few significant eruptions. Thus, there have been limited opportunities to test emerging hypotheses including, for example, the vexed question of the role of 'smaller' explosive eruptions in perturbations of the atmosphere—those that may just be large enough to reach the stratosphere (of size 'VEI 3', Newhall and Self 1982, Pyle 2000). Geological evidence, from ice-cores and historical eruptions, suggests that small explosive volcanic eruptions with the potential to transport material into the stratosphere should be frequent (5-10 per decade), and responsible for a significant proportion of the long-term time-averaged flux of volcanic sulfur into the stratosphere

  12. Eruptive and Geomorphic Processes at the Lathrop Wells Scoria Cone

    Energy Technology Data Exchange (ETDEWEB)

    G. Valentine; D.J. Krier; F.V. Perry; G. Heiken

    2006-08-03

    The {approx}80 ka Lathrop Wells volcano (southern Nevada, U.S.A.) preserves evidence for a range of explosive processes and emplacement mechanisms of pyroclastic deposits and lava fields in a small-volume basaltic center. Early cone building by Strombolian bursts was accompanied by development of a fan-like lava field reaching {approx}800 m distance from the cone, built upon a gently sloping surface. Lava flows carried rafts of cone deposits, which provide indirect evidence for cone facies in lieu of direct exposures in the active quarry. Subsequent activity was of a violent Strombolian nature, with many episodes of sustained eruption columns up to a few km in height. These deposited layers of scoria lapilli and ash in different directions depending upon wind direction at the time of a given episode, reaching up to {approx}20 km from the vent, and also produced the bulk of the scoria cone. Lava effusion migrated from south to north around the eastern base of the cone as accumulation of lavas successively reversed the topography at the base of the cone. Late lavas were emplaced during violent Strombolian activity and continued for some time after explosive eruptions had waned. Volumes of the eruptive products are: fallout--0.07 km{sup 3}, scoria cone--0.02 km{sup 3}, and lavas--0.03 km{sup 3}. Shallow-derived xenolith concentrations suggest an upper bound on average conduit diameter of {approx}21 m in the uppermost 335 m beneath the volcano. The volcano was constructed over a period of at least seven months with cone building occurring only during part of that time, based upon analogy with historical eruptions. Post-eruptive geomorphic evolution varied for the three main surface types that were produced by volcanic activity: (1) scoria cone, (2) low relief surfaces (including lavas) with abundant pyroclastic material, and (3) lavas with little pyroclastic material. The role of these different initial textures must be accounted for in estimating relative ages of

  13. Eruptive and Geomorphic Processes at the Lathrop Wells Scoria Cone

    International Nuclear Information System (INIS)

    G. Valentine; D.J. Krier; F.V. Perry; G. Heiken

    2006-01-01

    The ∼80 ka Lathrop Wells volcano (southern Nevada, U.S.A.) preserves evidence for a range of explosive processes and emplacement mechanisms of pyroclastic deposits and lava fields in a small-volume basaltic center. Early cone building by Strombolian bursts was accompanied by development of a fan-like lava field reaching ∼800 m distance from the cone, built upon a gently sloping surface. Lava flows carried rafts of cone deposits, which provide indirect evidence for cone facies in lieu of direct exposures in the active quarry. Subsequent activity was of a violent Strombolian nature, with many episodes of sustained eruption columns up to a few km in height. These deposited layers of scoria lapilli and ash in different directions depending upon wind direction at the time of a given episode, reaching up to ∼20 km from the vent, and also produced the bulk of the scoria cone. Lava effusion migrated from south to north around the eastern base of the cone as accumulation of lavas successively reversed the topography at the base of the cone. Late lavas were emplaced during violent Strombolian activity and continued for some time after explosive eruptions had waned. Volumes of the eruptive products are: fallout--0.07 km 3 , scoria cone--0.02 km 3 , and lavas--0.03 km 3 . Shallow-derived xenolith concentrations suggest an upper bound on average conduit diameter of ∼21 m in the uppermost 335 m beneath the volcano. The volcano was constructed over a period of at least seven months with cone building occurring only during part of that time, based upon analogy with historical eruptions. Post-eruptive geomorphic evolution varied for the three main surface types that were produced by volcanic activity: (1) scoria cone, (2) low relief surfaces (including lavas) with abundant pyroclastic material, and (3) lavas with little pyroclastic material. The role of these different initial textures must be accounted for in estimating relative ages of volcanic surfaces, and failure to

  14. A submarine volcanic eruption leads to a novel microbial habitat.

    Science.gov (United States)

    Danovaro, Roberto; Canals, Miquel; Tangherlini, Michael; Dell'Anno, Antonio; Gambi, Cristina; Lastras, Galderic; Amblas, David; Sanchez-Vidal, Anna; Frigola, Jaime; Calafat, Antoni M; Pedrosa-Pàmies, Rut; Rivera, Jesus; Rayo, Xavier; Corinaldesi, Cinzia

    2017-04-24

    Submarine volcanic eruptions are major catastrophic events that allow investigation of the colonization mechanisms of newly formed seabed. We explored the seafloor after the eruption of the Tagoro submarine volcano off El Hierro Island, Canary Archipelago. Near the summit of the volcanic cone, at about 130 m depth, we found massive mats of long, white filaments that we named Venus's hair. Microscopic and molecular analyses revealed that these filaments are made of bacterial trichomes enveloped within a sheath and colonized by epibiotic bacteria. Metagenomic analyses of the filaments identified a new genus and species of the order Thiotrichales, Thiolava veneris. Venus's hair shows an unprecedented array of metabolic pathways, spanning from the exploitation of organic and inorganic carbon released by volcanic degassing to the uptake of sulfur and nitrogen compounds. This unique metabolic plasticity provides key competitive advantages for the colonization of the new habitat created by the submarine eruption. A specialized and highly diverse food web thrives on the complex three-dimensional habitat formed by these microorganisms, providing evidence that Venus's hair can drive the restart of biological systems after submarine volcanic eruptions.

  15. Hot prominence detected in the core of a coronal mass ejection. II. Analysis of the C III line detected by SOHO/UVCS

    Science.gov (United States)

    Jejčič, S.; Susino, R.; Heinzel, P.; Dzifčáková, E.; Bemporad, A.; Anzer, U.

    2017-11-01

    Context. We study the physics of erupting prominences in the core of coronal mass ejections (CMEs) and present a continuation of a previous analysis. Aims: We determine the kinetic temperature and microturbulent velocity of an erupting prominence embedded in the core of a CME that occurred on August 2, 2000 using the Ultraviolet Coronagraph and Spectrometer observations (UVCS) on board the Solar and Heliospheric Observatory (SOHO) simultaneously in the hydrogen Lα and C III lines. We develop the non-LTE (departures from the local thermodynamic equilibrium - LTE) spectral diagnostics based on Lα and Lβ measured integrated intensities to derive other physical quantities of the hot erupting prominence. Based on this, we synthesize the C III line intensity to compare it with observations. Methods: Our method is based on non-LTE modeling of eruptive prominences. We used a general non-LTE radiative-transfer code only for optically thin prominence points because optically thick points do not allow the direct determination of the kinetic temperature and microturbulence from the line profiles. The input parameters of the code were the kinetic temperature and microturbulent velocity derived from the Lα and C III line widths, as well as the integrated intensity of the Lα and Lβ lines. The code runs in three loops to compute the radial flow velocity, electron density, and effective thickness as the best fit to the Lα and Lβ integrated intensities within the accuracy defined by the absolute radiometric calibration of UVCS data. Results: We analyzed 39 observational points along the whole erupting prominence because for these points we found a solution for the kinetic temperature and microturbulent velocity. For these points we ran the non-LTE code to determine best-fit models. All models with τ0(Lα) ≤ 0.3 and τ0(C III) ≤ 0.3 were analyzed further, for which we computed the integrated intensity of the C III line using a two-level atom. The best agreement between

  16. Hybrid Pyroclastic Deposits Accumulated From The Eruptive Transitional Regime of Plinian Eruptions.

    Science.gov (United States)

    di Muro, Andrea; Rosi, Mauro

    the crater only in a post-plinian phase. During this phase, the convective plume was purely coignimbritic. The runout (from 4 to 11 km) and the degree of valley -confinement progressively increased from S1 to S4 currents. The eruption ended with the collapse of a 2.6 km summit caldera. During this last eruptive phase, coarse lithic-rich flow units with runout shorter than previously were emplaced. The parallel evolution of column height (grain-size), fountain height (size of ballistics) and flow properties (surges vs. flows) compares well with the numerical simulations of pyroclastic dispersion performed by Neri et al. (2002). In the whole dispersion area, the fall bed has a polymodal grain-size. The coarse modes of the fall appear related to the plinian column, while the fines ones have a co-ignimbrite fall origin. Sub-pop ulation analysis shows that the fine modes are related to ash aggregation that in transitional eruptions plays a significant role in the deposition of very fine sizzes also in very proximal areas. The fall deposit is totally eroded and reworked by the syn-plinian currents in the proximal areas and partially eroded in the medial areas. Grain-size and maximum clast analysis indicate that a significant fraction of the intraplinian beds is of primary fall origin. Strong similarities are found between the Quilot oa deposits and that accumulated during the transitional phase of the 1991 Pinatubo eruption (Rosi et al., 2001). These evidences should be carefully taken in account for risk assessment when analysing deposits accumulated in the transitional eruptive regi me with the aim at calculating the physical parameters characterizing the density currents ( Brissette and Lajoie, 1990). References : Brissette FP and Lajoie J (1990) Depositional mechanics of turbulent nuées ardentes (surges) from their grain-sizes. Bull Volcanol 53:60-66. Carey S, Sigurdsson H, Sparks RSJ (1988) Experimental studies of particle-laden plumes. J Geophys Res 93

  17. ON THE MAGNETISM AND DYNAMICS OF PROMINENCE LEGS HOSTING TORNADOES

    Energy Technology Data Exchange (ETDEWEB)

    Martínez González, M. J.; Ramos, A. Asensio; Arregui, I.; Collados, M. [Instituto de Astrofísica de Canarias, Vía Láctea s/n, E-38205 La Laguna, Tenerife (Spain); Beck, C. [National Solar Observatory, Sacramento Peak P.O. Box 62, Sunspot, NM 88349 (United States); Rodríguez, J. de la Cruz [Institute for Solar Physics, Department of Astronomy, Stockholm University, Albanova University Center, SE-10691 Stockholm (Sweden)

    2016-07-10

    Solar tornadoes are dark vertical filamentary structures observed in the extreme ultraviolet associated with prominence legs and filament barbs. Their true nature and relationship to prominences requires an understanding of their magnetic structure and dynamic properties. Recently, a controversy has arisen: is the magnetic field organized forming vertical, helical structures or is it dominantly horizontal? And concerning their dynamics, are tornadoes really rotating or is it just a visual illusion? Here we analyze four consecutive spectro-polarimetric scans of a prominence hosting tornadoes on its legs, which helps us shed some light on their magnetic and dynamical properties. We show that the magnetic field is very smooth in all the prominence, which is probably an intrinsic property of the coronal field. The prominence legs have vertical helical fields that show slow temporal variation that is probably related to the motion of the fibrils. Concerning the dynamics, we argue that (1) if rotation exists, it is intermittent, lasting no more than one hour, and (2) the observed velocity pattern is also consistent with an oscillatory velocity pattern (waves).

  18. Solar Tornado Prominences: Plasma Motions Along Filament Barbs

    Science.gov (United States)

    Panasenco, Olga; Velli, Marco; Martin, Sara F.; Rappazzo, Franco

    2013-03-01

    Recent high-resolution observations from the Solar Dynamic Observatory (SDO) have reawakened interest in the old and fascinating phenomenon of solar tornado prominences. This class of prominences was first introduced by E. Pettit in 1932, who studied them over many years up to 1950. High resolution and high cadence multi-wavelength data obtained by SDO reveal that the tornado-like properties of these prominences are mainly an illusion due to projection effects. We show that counterstreaming plasma motions with projected velocities up to +/- 45 km/sec along the prominence spine and barbs create a tornado-like impression when viewed at the limb. We demonstrate that barbs are often rooted at the intersection between 4-5 supergranular cells. We discuss the observed oscillations along the vertical parts of barbs and whether they may be related to vortex flows coming from the convection downdrafts at the intersection of supergranules (and possibly smaller convective cells) in the photosphere and their entrained magnetic field. The unwinding of magnetic threads near the photosphere via reconnection might be a source of the waves which are observed as oscillations in prominence barbs.

  19. ON THE SUPPORT OF NEUTRALS AGAINST GRAVITY IN SOLAR PROMINENCES

    Energy Technology Data Exchange (ETDEWEB)

    Terradas, J.; Soler, R.; Oliver, R.; Ballester, J. L., E-mail: jaume.terradas@uib.es [Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain)

    2015-04-01

    Cool and dense prominences found in the solar atmosphere are known to be partially ionized because of their relatively low temperature. In this Letter, we address the long-standing problem of how the neutral component of the plasma in prominences is supported against gravity. Using the multiple-fluid approach, we solve the time-dependent equations in two dimensions considering the frictional coupling between the neutral and ionized components of the magnetized plasma representative of a solar prominence embedded in a hot coronal environment. We demonstrate that given an initial density enhancement in the two fluids, representing the body of the prominence, the system is able to relax in the vicinity of magnetic dips to a stationary state in which both neutrals and ionized species are dynamically suspended above the photosphere. Two different coupling processes are considered in this study: collisions between ions and neutrals and charge exchange interactions. We find that for realistic conditions, ions are essentially static, while neutrals have a very small downflow velocity. The coupling between ions and neutrals is so strong at the prominence body that the behavior is similar to that of a single fluid with an effective density equal to the sum of the ion and neutral species. We also find that the charge exchange mechanism is about three times more efficient at sustaining neutrals than elastic scattering of ions with neutrals.

  20. On the Magnetism and Dynamics of Prominence Legs Hosting Tornadoes

    Science.gov (United States)

    Martínez González, M. J.; Asensio Ramos, A.; Arregui, I.; Collados, M.; Beck, C.; de la Cruz Rodríguez, J.

    2016-07-01

    Solar tornadoes are dark vertical filamentary structures observed in the extreme ultraviolet associated with prominence legs and filament barbs. Their true nature and relationship to prominences requires an understanding of their magnetic structure and dynamic properties. Recently, a controversy has arisen: is the magnetic field organized forming vertical, helical structures or is it dominantly horizontal? And concerning their dynamics, are tornadoes really rotating or is it just a visual illusion? Here we analyze four consecutive spectro-polarimetric scans of a prominence hosting tornadoes on its legs, which helps us shed some light on their magnetic and dynamical properties. We show that the magnetic field is very smooth in all the prominence, which is probably an intrinsic property of the coronal field. The prominence legs have vertical helical fields that show slow temporal variation that is probably related to the motion of the fibrils. Concerning the dynamics, we argue that (1) if rotation exists, it is intermittent, lasting no more than one hour, and (2) the observed velocity pattern is also consistent with an oscillatory velocity pattern (waves).

  1. ON THE MAGNETISM AND DYNAMICS OF PROMINENCE LEGS HOSTING TORNADOES

    International Nuclear Information System (INIS)

    Martínez González, M. J.; Ramos, A. Asensio; Arregui, I.; Collados, M.; Beck, C.; Rodríguez, J. de la Cruz

    2016-01-01

    Solar tornadoes are dark vertical filamentary structures observed in the extreme ultraviolet associated with prominence legs and filament barbs. Their true nature and relationship to prominences requires an understanding of their magnetic structure and dynamic properties. Recently, a controversy has arisen: is the magnetic field organized forming vertical, helical structures or is it dominantly horizontal? And concerning their dynamics, are tornadoes really rotating or is it just a visual illusion? Here we analyze four consecutive spectro-polarimetric scans of a prominence hosting tornadoes on its legs, which helps us shed some light on their magnetic and dynamical properties. We show that the magnetic field is very smooth in all the prominence, which is probably an intrinsic property of the coronal field. The prominence legs have vertical helical fields that show slow temporal variation that is probably related to the motion of the fibrils. Concerning the dynamics, we argue that (1) if rotation exists, it is intermittent, lasting no more than one hour, and (2) the observed velocity pattern is also consistent with an oscillatory velocity pattern (waves).

  2. Volcanic Eruptions and Climate: Outstanding Research Issues

    Science.gov (United States)

    Robock, Alan

    2016-04-01

    Large volcanic eruptions inject sulfur gases into the stratosphere, which convert to sulfate aerosols with an e-folding residence time of about one year. The radiative and chemical effects of this aerosol cloud produce responses in the climate system. Based on observations after major eruptions of the past and experiments with numerical models of the climate system, we understand much about their climatic impact, but there are also a number of unanswered questions. Volcanic eruptions produce global cooling, and are an important natural cause of interannual, interdecadal, and even centennial-scale climate change. One of the most interesting volcanic effects is the "winter warming" of Northern Hemisphere continents following major tropical eruptions. During the winter in the Northern Hemisphere following every large tropical eruption of the past century, surface air temperatures over North America, Europe, and East Asia were warmer than normal, while they were colder over Greenland and the Middle East. This pattern and the coincident atmospheric circulation correspond to the positive phase of the Arctic Oscillation. While this response is observed after recent major eruptions, most state-of-the-art climate models have trouble simulating winter warming. Why? High latitude eruptions in the Northern Hemisphere, while also producing global cooling, do not have the same impact on atmospheric dynamics. Both tropical and high latitude eruptions can weaken the Indian and African summer monsoon, and the effects can be seen in past records of flow in the Nile and Niger Rivers. Since the Mt. Pinatubo eruption in the Philippines in 1991, there have been no large eruptions that affected climate, but the cumulative effects of small eruptions over the past decade have had a small effect on global temperature trends. Some important outstanding research questions include: How much seasonal, annual, and decadal predictability is possible following a large volcanic eruption? Do

  3. Sattelite Landsat for eruption of Mt. Sinabung

    Science.gov (United States)

    Tampubolon, T.; Yanti, J.

    2017-07-01

    Volcano eruption at the moment and will still last one of them is the eruption of Mount Sinabung. Sinabung eruption many lives that need to be done on disaster mitigation in order to provide early information about when the eruption would occur and could predict when the eruption would take place. Mount Sinabung had geographic coordinates 3°10'12 ″N 98°23'31″ E with an altitude of 2,460 meters above sea level. The research methodology used remote sensing technology as well as data such as satellite images Landsat with the output data of June 7th, 2013, March 6th 2014, 21 February 2015, 29 June 2015. The results determined the distribution pattern of temperatures that could steer which direction the larva as well as determined areas that need to be done evacuation or disaster mitigation in order to avoid the danger of eruption.

  4. Reconnection–Condensation Model for Solar Prominence Formation

    Energy Technology Data Exchange (ETDEWEB)

    Kaneko, Takafumi [Institute for Space-Earth Environmental Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601 (Japan); Yokoyama, Takaaki, E-mail: kaneko@isee.nagoya-u.ac.jp [Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2017-08-10

    We propose a reconnection–condensation model in which topological change in a coronal magnetic field via reconnection triggers radiative condensation, thereby resulting in prominence formation. Previous observational studies have suggested that reconnection at a polarity inversion line of a coronal arcade field creates a flux rope that can sustain a prominence; however, they did not explain the origin of cool dense plasmas of prominences. Using three-dimensional magnetohydrodynamic simulations, including anisotropic nonlinear thermal conduction and optically thin radiative cooling, we demonstrate that reconnection can lead not only to flux rope formation but also to radiative condensation under a certain condition. In our model, this condition is described by the Field length, which is defined as the scale length for thermal balance between radiative cooling and thermal conduction. This critical condition depends weakly on the artificial background heating. The extreme ultraviolet emissions synthesized with our simulation results have good agreement with observational signatures reported in previous studies.

  5. Solitary eccrine syringofibroadenoma with prominent plasma cell infiltration.

    Science.gov (United States)

    Kim, Ji Yeon; Kim, You Chan; Lee, Eun-So

    2007-02-01

    Eccrine syringofibroadenoma (ESFA) is a rare, benign, adnexal neoplasm thought to be eccrine ductal differentiation displaying variable clinical findings and characteristic histological features. It usually occurs as a solitary nodule on the extremities of an elderly person. Histological findings typically show a proliferation of anastomosing strands, cords, and columns of monomorphous epithelial cells that harbor eccrine duct formations embedded in a fibrovascular stroma. Acrosyringial nevus, though usually regarded as an identical lesion, is sometimes regarded as a different entity showing prominent plasma cell infiltration. We report two cases of solitary ESFA with prominent plasma cell infiltration. Clinicopathological features of both cases suggest that acrosyringeal nevus and ESFA may be of the same disease entity. Prominent plasma cell infiltration may be just one of the common histological features of ESFA.

  6. From Wilhelm von Humboldt to Hitler-are prominent people more prone to have Parkinson's disease?

    Science.gov (United States)

    Horowski; Horowski; Calne; Calne

    2000-10-01

    We describe Parkinsonism in prominent people, where Wilhelm von Humboldt and Adolf Hitler provide just two spectacular, opposing examples. In both of them, there is little if any evidence that the disease did influence their life ambitions, methods of achieving them or cognitive function in general. Thus, Hitler's Parkinsonism should remain a 'footnote' to history, and historians should acknowledge that in his last years, his trembling, his curbed posture, his slow walking, mask-like face and low voice did not indicate remorse, fear or depression as a consequence of his crimes, but were mere expressions of his disease which, until the end, had no impact on his intellectual skills and methods. The apparently higher incidence of Parkinsonism in prominent people may be just due to their higher visibility, or a consequence of disease-related personality traits (e.g. ambition, perfectionism, rigidity) which may contribute to becoming, e.g., a prominent authoritarian person. Perhaps even some early behaviour pattern (such as repressed emotions or acting in public-which could even increase the risk of some infection) contributes to a greater vulnerability for developing Parkinsonism. Further studying other prominent cases might lead us to better understanding of risk factors and the expression of early Parkinsonism.

  7. Solar Prominence Modelling and Plasma Diagnostics at ALMA Wavelengths

    Science.gov (United States)

    Rodger, Andrew; Labrosse, Nicolas

    2017-09-01

    Our aim is to test potential solar prominence plasma diagnostics as obtained with the new solar capability of the Atacama Large Millimeter/submillimeter Array (ALMA). We investigate the thermal and plasma diagnostic potential of ALMA for solar prominences through the computation of brightness temperatures at ALMA wavelengths. The brightness temperature, for a chosen line of sight, is calculated using the densities of electrons, hydrogen, and helium obtained from a radiative transfer code under non-local thermodynamic equilibrium (non-LTE) conditions, as well as the input internal parameters of the prominence model in consideration. Two distinct sets of prominence models were used: isothermal-isobaric fine-structure threads, and large-scale structures with radially increasing temperature distributions representing the prominence-to-corona transition region. We compute brightness temperatures over the range of wavelengths in which ALMA is capable of observing (0.32 - 9.6 mm), however, we particularly focus on the bands available to solar observers in ALMA cycles 4 and 5, namely 2.6 - 3.6 mm (Band 3) and 1.1 - 1.4 mm (Band 6). We show how the computed brightness temperatures and optical thicknesses in our models vary with the plasma parameters (temperature and pressure) and the wavelength of observation. We then study how ALMA observables such as the ratio of brightness temperatures at two frequencies can be used to estimate the optical thickness and the emission measure for isothermal and non-isothermal prominences. From this study we conclude that for both sets of models, ALMA presents a strong thermal diagnostic capability, provided that the interpretation of observations is supported by the use of non-LTE simulation results.

  8. Dapsone-associated fixed drug eruption.

    Science.gov (United States)

    Garcia, Daniel; Cohen, Philip R

    2017-07-01

    Dapsone is a sulfone drug used to treat infectious conditions and also numerous dermatologic diseases. Fixed drug eruption is a distinctive adverse cutaneous reaction associated with the initial administration and subsequent delivery of a specific agent. Areas covered: The authors preformed a literature search using the following keywords: dapsone, fixed drug eruption, and adverse cutaneous drug reaction. Bibliographies were also reviewed for pertinent articles. The results were combed for relevant papers and reviewed. Articles pertaining to dapsone-associated fixed drug eruption were included. Expert commentary: The majority of cases of dapsone-associated fixed drug eruption in the literature come from Africa or India where there is a high prevalence of patients treated for leprosy. Characteristics of these cases are similar to fixed drug eruption described in the western literature, with differences in frequency of multiple versus solitary lesions. Dapsone-associated fixed drug eruption should be considered when reviewing the drug history of a patient with fixed drug eruption. In the case of darker pigmented individuals, multiple fixed drug eruption lesions may be more common. Multiple lesions may mimic Kaposi's sarcoma in human immunodeficiency virus positive patients. Dapsone-associated fixed drug eruption should be considered in the differential diagnosis of multiple hyperpigmented lesions.

  9. Multiple dendrochronological responses to the eruption of Cinder Cone, Lassen Volcanic National Park, California

    Science.gov (United States)

    Sheppard, P.R.; Ort, M.H.; Anderson, K.C.; Clynne, M.A.; May, E.M.

    2009-01-01

    Two dendrochronological properties – ring width and ring chemistry – were investigated in trees near Cinder Cone in Lassen Volcanic National Park, northeastern California, for the purpose of re-evaluating the date of its eruption. Cinder Cone is thought to have erupted in AD 1666 based on ring-width evidence, but interpreting ring-width changes alone is not straightforward because many forest disturbances can cause changes in ring width. Old Jeffrey pines growing in Cinder Cone tephra and elsewhere for control comparison were sampled. Trees growing in tephra show synchronous ring-width changes at AD 1666, but this ring-width signal could be considered ambiguous for dating the eruption because changes in ring width can be caused by other events. Trees growing in tephra also show changes in ring phosphorus, sulfur, and sodium during the late 1660s, but inter-tree variability in dendrochemical signals makes dating the eruption from ring chemistry alone difficult. The combination of dendrochemistry and ring-width signals improves confidence in dating the eruption of Cinder Cone over the analysis of just one ring-growth property. These results are similar to another case study using dendrochronology of ring width and ring chemistry at Parícutin, Michoacán, Mexico, a cinder cone that erupted beginning in 1943. In both cases, combining analysis with ring width and ring chemistry improved confidence in the dendro-dating of the eruptions.

  10. The eruptive history and volcanic hazards of Savo, Solomon Islands

    Science.gov (United States)

    Petterson, M. G.; Cronin, S. J.; Taylor, P. W.; Tolia, D.; Papabatu, A.; Toba, T.; Qopoto, C.

    2002-11-01

    strong evidence for syn- and post-eruptive redeposition of primary deposits. Since the Savo population is concentrated on coastal volcaniclastic fans, we consider the greatest volcanic risk to life is from BAFs, associated ash-cloud surges and lahars. Hence, the main channels and fans are designated as the highest of three relative hazard zones on a simple map prepared to aid local education and planning initiatives on Savo.

  11. Rapid transport of ash and sulfate from the 2011 Puyehue-Cordón Caulle (Chile) eruption to West Antarctica

    Science.gov (United States)

    Koffman, Bess G.; Dowd, Eleanor G.; Osterberg, Erich C.; Ferris, David G.; Hartman, Laura H.; Wheatley, Sarah D.; Kurbatov, Andrei V.; Wong, Gifford J.; Markle, Bradley R.; Dunbar, Nelia W.; Kreutz, Karl J.; Yates, Martin

    2017-08-01

    The Volcanic Explosivity Index 5 eruption of the Puyehue-Cordón Caulle volcanic complex (PCC) in central Chile, which began 4 June 2011, provides a rare opportunity to assess the rapid transport and deposition of sulfate and ash from a midlatitude volcano to the Antarctic ice sheet. We present sulfate, microparticle concentrations of fine-grained ( 5 μm diameter) tephra, and major oxide geochemistry, which document the depositional sequence of volcanic products from the PCC eruption in West Antarctic snow and shallow firn. From the depositional phasing and duration of ash and sulfate peaks, we infer that transport occurred primarily through the troposphere but that ash and sulfate transport were decoupled. We use Hybrid Single-Particle Lagrangian Integrated Trajectory back trajectory modeling to assess atmospheric circulation conditions in the weeks following the eruption and find that conditions favored southward air parcel transport during 6-14 June and 4-18 July 2011. We suggest that two discrete pulses of cryptotephra deposition relate to these intervals, and as such, constrain the sulfate transport and deposition lifespan to the 2-3 weeks following the eruption. Finally, we compare PCC depositional patterns to those of prominent low- and high-latitude eruptions in order to improve multiparameter-based efforts to identify "unknown source" eruptions in the ice core record. Our observations suggest that midlatitude eruptions such as PCC can be distinguished from explosive tropical eruptions by differences in ash/sulfate phasing and in the duration of sulfate deposition, and from high-latitude eruptions by differences in particle size distribution and in cryptotephra geochemical composition.

  12. Rapid transport of ash and sulfate from the 2011 Puyehue-Córdon Caulle (Chile) eruption to West Antarctica

    Science.gov (United States)

    Dowd, E.; Koffman, B. G.; Osterberg, E. C.; Ferris, D. G.; Hartman, L.; Wheatley, S.; Kurbatov, A.; Wong, G. J.; Markle, B. R.; Dunbar, N. W.; Kreutz, K. J.; Yates, M. G.

    2017-12-01

    The VEI 5 eruption of the Puyehue-Cordón Caulle volcanic complex (PCC) in central Chile, which began 4 June 2011, provides a rare opportunity to assess the rapid transport and deposition of sulfate and ash from a mid-latitude volcano to the Antarctic ice sheet. We present sulfate, microparticle concentrations of fine-grained ( 5 μm diameter) tephra, and geochemistry, which document the depositional sequence of volcanic products from the PCC eruption in West Antarctic snow and shallow firn. From the depositional phasing and duration of ash and sulfate peaks, we infer that transport occurred primarily through the troposphere but that ash and sulfate transport were decoupled. We use Hysplit back-trajectory modeling to assess circulation conditions in the weeks following the eruption, and find that atmospheric conditions favored mid-to-high latitude air parcel transport during 6-14 June and 4-18 July, 2011. We suggest that two discrete pulses of cryptotephra deposition relate to these intervals, and as such, constrain the sulfate transport and deposition lifespan to the 2-3 weeks following the eruption. Finally, we compare PCC depositional patterns to those of prominent low- and high-latitude eruptions in order to improve multiparameter-based efforts to identify "unknown source" eruptions in the ice core record. Our observations suggest that mid-latitude eruptions such as PCC can be distinguished from explosive tropical eruptions by differences in ash/sulfate phasing and in the duration of sulfate deposition, and from high-latitude eruptions by differences in particle size distribution and in cryptotephra geochemical composition.

  13. Dynamical study on eruptive gases

    International Nuclear Information System (INIS)

    Le Guern, Francois

    1972-11-01

    Up to 1968 to 1971, a group of 'Commissariat a l'Energie Atomique' furnishes the technical support of C. N. R. S. studies on volcanic activity. The present work contains a description of technical solutions adopted, the results obtained on the physical and chemical parameters. We try to explain the mechanisms of volcanic activity in Ethiopia (ERTA-ALE) or in Italy (ETNA, VULCANO). Such a work permits to forecast eruptive paroxysms, to use volcanic energy and to know better mineral concentrations. (author) [fr

  14. SANTORINI BEFORE THE MINOAN ERUPTION

    DEFF Research Database (Denmark)

    Friedrich, Walter L.; Sørensen, Annette Højen; Katsipis, Samson

    2014-01-01

    Conclusions Several detailed geological observations in the landscape of Santorini enable us to claim that the two harbour towns were located on the inner side of the caldera wall on the island of Thera prior to the Minoan Eruption. This hypothesis is in agreement with the excavation sites of Bal...... that the fresco shows a joyful scene where the inhabitants of Bronze Age Santorini celebrate the seasonal change in connection with the arrival of life-giving rainwater either at the beginning of spring or at the end of the sailing season in autumn (Pl. CXLVIIc)....

  15. Unintended exposure in radiotherapy: identification of prominent causes.

    Science.gov (United States)

    Boadu, Mary; Rehani, Madan Mohan

    2009-12-01

    Unintended exposures in radiotherapy are likely to occur when certain conditions that favour such exposures exist. Based on the frequency of occurrence of various causes of 100 events of unintended exposures in radiotherapy as derived from the analysis of published reports, a checklist for assessing the vulnerability of radiotherapy facilities for potential accidents has been prepared. The list presents items to be considered for safety critical assessments of a radiotherapy department for the improvement of patient safety and the entire radiotherapy processes. The resources used for this paper consist of 100 unintended radiotherapy exposures and were derived from existing published reports. The analysis was performed by forming two templates: one consisting of 10 initiating events and another of 35 contributing factors. Four most prominent initiating events were identified and together accounted for about 70% of all the unintended exposure events. Ten most prominent contributing factors were also identified and together accounted for about 70% of all the radiotherapy unintended exposure events covered under this study. With this knowledge of high frequency of occurrences, the identified four prominent initiating events and the 10 most prominent contributing factors must be checked and dealt with as a matter of priority when assessing the safety of a radiotherapy facility. A simple checklist for checking the quality assurance programmes of a radiotherapy department for every aspect of the design and delivery of radiation have been provided.

  16. On Estimation of the Optical Thickness of Solar Prominences

    Czech Academy of Sciences Publication Activity Database

    Milic, I.; Dejanič, S.; Kotrč, Pavel

    2009-01-01

    Roč. 86, - (2009), s. 283-286 ISSN 0373-3742. [National conference of astronomers of Serbia /15./. Beograd, 02.10.2008-05.10.2008] Institutional research plan: CEZ:AV0Z10030501 Keywords : optical thickness * solar prominences Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  17. PATTERNS OF FLOWS IN AN INTERMEDIATE PROMINENCE OBSERVED BY HINODE

    International Nuclear Information System (INIS)

    Ahn, Kwangsu; Chae, Jongchul; Cao Wenda; Goode, Philip R.

    2010-01-01

    The investigation of plasma flows in filaments/prominences gives us clues to understanding their magnetic structures. We studied the patterns of flows in an intermediate prominence observed by Hinode/SOT. By examining a time series of Hα images and Ca II H images, we have found horizontal flows in the spine and vertical flows in the barb. Both of these flows have a characteristic speed of 10-20 km s -1 . The horizontal flows displayed counterstreaming. Our detailed investigation revealed that most of the moving fragments in fact reversed direction at the end point of the spine near a footpoint close to the associated active region. These returning flows may be one possible explanation of the well-known counterstreaming flows in prominences. In contrast, we have found vertical flows-downward and upward-in the barb. Most of the horizontal flows in the spine seem to switch into vertical flows when they approach the barb, and vice versa. We propose that the net force resulting from a small deviation from magnetohydrostatic equilibrium, where magnetic fields are predominantly horizontal, may drive these patterns of flow. In the prominence studied here, the supposed magnetohydrostatic configuration is characterized by magnetic field lines sagging with angles of 13 0 and 39 0 in the spine and the barb, respectively.

  18. The Most Prominent Roles of an ESP Teacher

    Science.gov (United States)

    Ghafournia, Narjes; Sabet, Shokoofeh Ahmadian

    2014-01-01

    One prominent feature of many ESP (English for Specific Purposes) courses, which make them rather different from EGP (English for General Purposes) courses, is the presence of adult learners, who are primary workers and secondary learners. As ESP is a highly learner-cantered approach, paying close attention to the multidimensional needs of…

  19. SPATIAL DAMPING OF PROPAGATING KINK WAVES IN PROMINENCE THREADS

    International Nuclear Information System (INIS)

    Soler, R.; Oliver, R.; Ballester, J. L.

    2011-01-01

    Transverse oscillations and propagating waves are frequently observed in threads of solar prominences/filaments and have been interpreted as kink magnetohydrodynamic (MHD) modes. We investigate the spatial damping of propagating kink MHD waves in transversely nonuniform and partially ionized prominence threads. Resonant absorption and ion-neutral collisions (Cowling's diffusion) are the damping mechanisms taken into account. The dispersion relation of resonant kink waves in a partially ionized magnetic flux tube is numerically solved by considering prominence conditions. Analytical expressions of the wavelength and damping length as functions of the kink mode frequency are obtained in the thin tube and thin boundary approximations. For typically reported periods of thread oscillations, resonant absorption is an efficient mechanism for the kink mode spatial damping, while ion-neutral collisions have a minor role. Cowling's diffusion dominates both the propagation and damping for periods much shorter than those observed. Resonant absorption may explain the observed spatial damping of kink waves in prominence threads. The transverse inhomogeneity length scale of the threads can be estimated by comparing the observed wavelengths and damping lengths with the theoretically predicted values. However, the ignorance of the form of the density profile in the transversely nonuniform layer introduces inaccuracies in the determination of the inhomogeneity length scale.

  20. Unintended exposure in radiotherapy: Identification of prominent causes

    International Nuclear Information System (INIS)

    Boadu, Mary; Rehani, Madan Mohan

    2009-01-01

    Background and purpose: Unintended exposures in radiotherapy are likely to occur when certain conditions that favour such exposures exist. Based on the frequency of occurrence of various causes of 100 events of unintended exposures in radiotherapy as derived from the analysis of published reports, a checklist for assessing the vulnerability of radiotherapy facilities for potential accidents has been prepared. The list presents items to be considered for safety critical assessments of a radiotherapy department for the improvement of patient safety and the entire radiotherapy processes. Materials and methods: The resources used for this paper consist of 100 unintended radiotherapy exposures and were derived from existing published reports. The analysis was performed by forming two templates: one consisting of 10 initiating events and another of 35 contributing factors. Results: Four most prominent initiating events were identified and together accounted for about 70% of all the unintended exposure events. Ten most prominent contributing factors were also identified and together accounted for about 70% of all the radiotherapy unintended exposure events covered under this study. Conclusion: With this knowledge of high frequency of occurrences, the identified four prominent initiating events and the 10 most prominent contributing factors must be checked and dealt with as a matter of priority when assessing the safety of a radiotherapy facility. A simple checklist for checking the quality assurance programmes of a radiotherapy department for every aspect of the design and delivery of radiation have been provided.

  1. On Lyman-line asymmetries in quiescent prominences

    Czech Academy of Sciences Publication Activity Database

    Gunár, Stanislav; Heinzel, Petr; Anzer, U.; Schmieder, B.

    2008-01-01

    Roč. 490, č. 1 (2008), s. 307-313 ISSN 0004-6361 Grant - others:EU(XE) ESA-PECS project No. 98030 Institutional research plan: CEZ:AV0Z10030501 Keywords : Sun prominences * radiative transfer * line profiles Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.153, year: 2008

  2. Aggressive Cue Prominence and Gender Participation in MTV.

    Science.gov (United States)

    Kalis, Pamela; Neuendorf, Kimberly A.

    1989-01-01

    Explores the content and structure of music videos, focusing on the pervasiveness of aggressive cues (objects or events representing physical harm or the threat of harm), gender portrayals within a context of aggression, and the pacing of music videos. Finds that aggressive cues in music videos are less prominent than critics indicate. (MM)

  3. Holdaway's analysis of the nose prominence of an adult Nigerian ...

    African Journals Online (AJOL)

    The nose prominence was assessed using Holdaway's analysis. Twenty radiographs randomly selected, were retraced to assess for errors. Data analysis included descriptive statistics, Student's t‑tests and analysis of variance using the Statistical Package for Social Sciences. Results: The mean value recorded for the nose ...

  4. Thermal Properties of Moving UV Features in Prominences

    Science.gov (United States)

    Kucera, Therese A.

    2003-01-01

    Multi-thermal features with speeds of 5-70 kilometers per second perpendicular to the line of sight are common in the prominences which showed traceable motions. These speeds are noticeably higher than the typical speeds of 5-20 kilometers per second observed in H-alpha data from "quiet" prominences and are more typical of "activated" prominences in which H-alpha blob speeds of up to 40 kilometers per second have been reported. In order to make a more quantitative determination of the thermal properties of the moving features seen in the UV, we use the SOHO instruments SUMER and CDS to take a time series of exposures from a single pointing position, providing a measurement of spectral line properties as a function of time and position along the slit. The resulting observations in lines spectral lines in a range of "transition region" temperatures allow us to analyze the thermal properties of the moving prominence sources as a function of time.

  5. Lines of MgI Detected in Solar Prominences

    Czech Academy of Sciences Publication Activity Database

    Heinzel, Petr; Kupryakov, Yu. A.; Schwartz, P.

    2016-01-01

    Roč. 40, č. 1 (2016), s. 87-91 ISSN 1845-8319. [Hvar Astrophysical Colloquium /14./. Hvar, 26.09.2016-30.09.2016] Institutional support: RVO:67985815 Keywords : prominences * limb-flare * MgI emession Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  6. Whole genome microarray analysis of chicken embryo facial prominences

    Czech Academy of Sciences Publication Activity Database

    Buchtová, Marcela; Kuo, W. P.; Nimmagadda, S.; Benson, S. L.; Geetha-Loganathan, P.; Logan, C.; Au-Yeung, T.; Chiang, E.; Fu, K.; Richman, J. M.

    2010-01-01

    Roč. 239, - (2010), s. 574-591 ISSN 1058-8388 Institutional research plan: CEZ:AV0Z50450515 Keywords : pharyngeal arch * mandibular arch * maxillary prominence Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.864, year: 2010

  7. Long-term Cyclic Variations of Prominences, Green and Red ...

    Indian Academy of Sciences (India)

    Abstract. Long-term cyclic variations in the distribution of promi- nences and intensities of green (530.3 nm) and red (637.4 nm) coronal emission lines over solar cycles 18-23 are presented. Polar prominence branches will reach the poles at different epochs in cycle 23: the north branch at the beginning in 2002 and the ...

  8. Multi-Wavelength Eclipse Observations of a Quiescent Prominence

    Czech Academy of Sciences Publication Activity Database

    Jejčič, S.; Heinzel, Petr; Zapiór, M.; Druckmüller, M.; Gunár, Stanislav; Kotrč, Pavel

    2014-01-01

    Roč. 289, č. 7 (2014), s. 2487-2501 ISSN 0038-0938 R&D Projects: GA ČR GAP209/12/0906 Institutional support: RVO:67985815 Keywords : eclipse observations * prominences * quiescent Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.039, year: 2014

  9. Electron densities in quiescent prominences derived from eclipse observations

    Czech Academy of Sciences Publication Activity Database

    Jejčič, S.; Heinzel, Petr

    2009-01-01

    Roč. 254, č. 1 (2009), s. 89-100 ISSN 0038-0938 Grant - others:EU(XE) ESA-PECS project No. 98030 Institutional research plan: CEZ:AV0Z10030501 Keywords : prominences quiescent * eclipse observations * visible spectrum Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.628, year: 2009

  10. Microfilament-Eruption Mechanism for Solar Spicules

    Science.gov (United States)

    Sterling, Alphonse C.; Moore, Ronald L.

    2017-01-01

    Recent studies indicate that solar coronal jets result from eruption of small-scale filaments, or "minifilaments" (Sterling et al. 2015, Nature, 523, 437; Panesar et al. ApJL, 832L, 7). In many aspects, these coronal jets appear to be small-scale versions of long-recognized large-scale solar eruptions that are often accompanied by eruption of a large-scale filament and that produce solar flares and coronal mass ejections (CMEs). In coronal jets, a jet-base bright point (JBP) that is often observed to accompany the jet and that sits on the magnetic neutral line from which the minifilament erupts, corresponds to the solar flare of larger-scale eruptions that occurs at the neutral line from which the large-scale filament erupts. Large-scale eruptions are relatively uncommon (approximately 1 per day) and occur with relatively large-scale erupting filaments (approximately 10 (sup 5) kilometers long). Coronal jets are more common (approximately 100s per day), but occur from erupting minifilaments of smaller size (approximately 10 (sup 4) kilometers long). It is known that solar spicules are much more frequent (many millions per day) than coronal jets. Just as coronal jets are small-scale versions of large-scale eruptions, here we suggest that solar spicules might in turn be small-scale versions of coronal jets; we postulate that the spicules are produced by eruptions of "microfilaments" of length comparable to the width of observed spicules (approximately 300 kilometers). A plot of the estimated number of the three respective phenomena (flares/CMEs, coronal jets, and spicules) occurring on the Sun at a given time, against the average sizes of erupting filaments, minifilaments, and the putative microfilaments, results in a size distribution that can be fitted with a power-law within the estimated uncertainties. The counterparts of the flares of large-scale eruptions and the JBPs of jets might be weak, pervasive, transient brightenings observed in Hinode/CaII images, and

  11. The 2014 eruptions of Pavlof Volcano, Alaska

    Science.gov (United States)

    Waythomas, Christopher F.; Haney, Matthew M.; Wallace, Kristi; Cameron, Cheryl E.; Schneider, David J.

    2017-12-22

    Pavlof Volcano is one of the most frequently active volcanoes in the Aleutian Island arc, having erupted more than 40 times since observations were first recorded in the early 1800s . The volcano is located on the Alaska Peninsula (lat 55.4173° N, long 161.8937° W), near Izembek National Wildlife Refuge. The towns and villages closest to the volcano are Cold Bay, Nelson Lagoon, Sand Point, and King Cove, which are all within 90 kilometers (km) of the volcano (fig. 1). Pavlof is a symmetrically shaped stratocone that is 2,518 meters (m) high, and has about 2,300 m of relief. The volcano supports a cover of glacial ice and perennial snow roughly 2 to 4 cubic kilometers (km3) in volume, which is mantled by variable amounts of tephra fall, rockfall debris, and pyroclastic-flow deposits produced during historical eruptions. Typical Pavlof eruptions are characterized by moderate amounts of ash emission, lava fountaining, spatter-fed lava flows, explosions, and the accumulation of unstable mounds of spatter on the upper flanks of the volcano. The accumulation and subsequent collapse of spatter piles on the upper flanks of the volcano creates hot granular avalanches, which erode and melt snow and ice, and thereby generate watery debris-flow and hyperconcentrated-flow lahars. Seismic instruments were first installed on Pavlof Volcano in the early 1970s, and since then eruptive episodes have been better characterized and specific processes have been documented with greater certainty. The application of remote sensing techniques, including the use of infrasound data, has also aided the study of more recent eruptions. Although Pavlof Volcano is located in a remote part of Alaska, it is visible from Cold Bay, Sand Point, and Nelson Lagoon, making distal observations of eruptive activity possible, weather permitting. A busy air-travel corridor that is utilized by a numerous transcontinental and regional air carriers passes near Pavlof Volcano. The frequency of air travel

  12. The Effects of Partial Ionization on Prominence Mass Formation

    Science.gov (United States)

    Karpen, J. T.; Olson, K.; DeVore, C. R.; Martinez Gomez, D.; Sokolov, I.

    2015-12-01

    The origin of the prominence mass has been an open question since this cool plasma suspended in the hot corona was first discovered. We have known for a long time that the mass must come from the chromosphere, but it is unclear whether this mass is lifted bodily through magnetic levitation, injected by reconnection-driven upflows, or driven from the chromosphere by evaporation and then condensed. One evaporation-condensation scenario, the thermal nonequilibrium (TNE) model, is the most fully developed, quantitative model for the prominence plasma to date. In the TNE scenario, localized heating concentrated at the coronal loop footpoints produces chromospheric evaporation, filling the flux tube with hot, dense plasma that subsequently collapses radiatively to form cool condensations. Thus far this model has been successful in explaining the key properties of the long, persistent threads and small, highly dynamic, transient blobs in prominences, the damping of large-amplitude field-aligned prominence oscillations, the appearance of horn-shaped features above the cool prominence in EUV images of coronal cavities, and coronal rain in the ambient corona. To date, all studies of TNE have assumed that the plasma is fully ionized, which is appropriate for the hot coronal gas but unrealistic for the cool plasma below ~30,000 K. The energetics, dynamics, and evolutionary time scales of the TNE process are expected to be altered when the effects of ionization and recombination are considered. We have modified ARGOS, our 1D hydrodynamic code with adaptive mesh refinement, to include an equation of state that accounts for the effects of partial ionization of the plasma over a wide range of temperatures and densities. We will discuss the results of these simulations and their comparison with our previous studies of TNE in typical filament-supporting flux tubes. This work was partially supported by NASA's LWS Strategic Capability program.

  13. Global Significant Volcanic Eruptions Database, 4360 BC to present

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Significant Volcanic Eruptions Database is a global listing of over 600 eruptions from 4360 BC to the present. A significant eruption is classified as one that...

  14. Masculinization of the eruption pattern of permanent mandibular canines in opposite sex twin girls.

    Science.gov (United States)

    Heikkinen, Tuomo; Harila, Virpi; Tapanainen, Juha S; Alvesalo, Lassi

    2013-08-01

    The aim of this study is to explore the effect of prenatal androgenization on the clinical eruption of permanent teeth expressing dimorphism and bimaturism. The eruption curves of permanent teeth (except third molars), including those that make up the canine complex (permanent canines, lower first premolars), are compared among opposite sex twins (OS twins) relative to single-born boys and girls. The comparisons are made with regard to three phases of eruption (pierced mucosa, half- erupted, and completely erupted) from a cross-sectional sample of dental casts, using Kaplan-Meier survival and Cox regression analyzes. The casts were collected from 2159 school children from the US Collaborative Perinatal Project, including 39 pairs of OS-twins, of which 12 pairs (30.8%) were Euro-Americans and 27 pairs (69.2%) were of African-American ancestry. The eruption patterns of the incisors, upper first molars, and lower canines were found to be significantly masculinized (delayed) among OS twin girls. The differences in most other teeth were either not significant, or the number of observations of active eruption phases were too few, such as in the upper first molars and incisors, to yield strong evidence and meaningful results. The masculinization of the tooth eruption pattern in OS twin girls is intriguing because of the lower canine responses during puberty, as well as canine primordial formation during early fetal androgenization of their co-twin during the 8th to 14th gestational weeks. The present results offer a challenge for future research exploring tooth eruption mechanisms, and may also highlight some cases of delayed or ectopic canines, which are biased toward females. Copyright © 2013 Wiley Periodicals, Inc.

  15. Insights into the Toba Super-Eruption using SEM Analysis of Ash Deposits

    Science.gov (United States)

    Gatti, E.; Achyuthan, H.; Durant, A. J.; Gibbard, P.; Mokhtar, S.; Oppenheimer, C.; Raj, R.; Shridar, A.

    2010-12-01

    The ~74 ka Youngest Toba Tuff (YTT) super-eruption of Toba volcano, Northern Sumatra, was the largest eruption of the Quaternary (magnitude M= 8.8) and injected massive quantities of volcanic gases and ash into the stratosphere. YTT deposits covered at least 40,000,000 km2 of Southeast Asia and are preserved in river valleys across peninsular India and Malaysia, and in deep-sea tephra layers in the Indian Ocean, Bay of Bengal and South China Sea. Initial studies hypothesized the eruption caused immediate and substantial global cooling during the ~ 1 kyr between Dansgaard-Oeschger events 19 and 20 which devastated ecosystems and hominid populations. A more recent review argues against severe post-YTT climatic deterioration and cannot find clear evidence for considerable impacts on ecosystems or bio-diversity. The determination of the eruptive parameters is crucial in this issue to document the eruption and understand the potential impacts from future super-volcanic eruptions. Volcanic ash deposits can offer dramatic insights into key eruptive parameters, including magnitude, duration and plume height. The composition and shape of volcanic ashes can be used to interpret physical properties of an erupting magma and tephra transport, while textural characteristics such as grain roughness and surface vescicularity can provide insights into degassing history, volatile content and explosive activity of the volcano. We present a stratigraphic and sedimentological analysis of YTT deposits in stratified contexts at three localities in India, at two sites in Peninsular Malaysia, and at several localities around Lake Toba and on Samosir Island, Sumatra. These sites offer excellent constraints on the spatial distribution of YTT deposits which can be used to infer dispersal directions of the cloud, and provide insights into environmental controls on preservation of tephra beds. The research aims at a systematic interpretation of the Toba tephra to understand the volcanic

  16. [Recognizing and preventing disturbances in eruption].

    Science.gov (United States)

    van der Linden, F P G M

    2014-04-01

    Disturbances in eruption and related problems are quite common in permanent dentition but rare in deciduous dentition. For the timely recognition of disturbances in eruption, knowledge of the normal development of dentition is essential. Disturbances in eruption comprise disturbances in which eruption does not occur at all, in which it is delayed or incomplete, or in which the normal direction of eruption is influenced. If identified early enough, many undesirable dental conditions can be avoided or their seriousness can be limited. A possible impacting of permanent cuspids, for example, can be avoided by extracting the deciduous cuspids at the right moment; in cases of a large overjet or the threat of a cover-bite, lip interference can be prevented.

  17. Non-LTE hydrogen-line formation in moving prominences

    Science.gov (United States)

    Heinzel, P.; Rompolt, B.

    1986-01-01

    The behavior of hydrogen-line brightness variations, depending on the prominence-velocity changes were investigated. By solving the NON-Local thermodynamic equilibrium (LTE) problem for hydrogen researchers determine quantitatively the effect of Doppler brightening and/or Doppler dimming (DBE, DDE) in the lines of Lyman and Balmer series. It is demonstrated that in low-density prominence plasmas, DBE in H alpha and H beta lines can reach a factor of three for velocities around 160 km/sec, while the L alpha line exhibits typical DDE. L beta brightness variations follow from a combined DBE in the H alpha and DDE in L alpha and L beta itself, providing that all relevant multilevel interlocking processes are taken into account.

  18. STRUCTURE OF PROMINENCE LEGS: PLASMA AND MAGNETIC FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Levens, P. J.; Labrosse, N. [SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ (United Kingdom); Schmieder, B. [Observatoire de Paris, Meudon, F-92195 (France); Ariste, A. López, E-mail: p.levens.1@research.gla.ac.uk [Institut de Recherche en Astrophysique et Planétologie, Toulouse (France)

    2016-02-10

    We investigate the properties of a “solar tornado” observed on 2014 July 15, and aim to link the behavior of the plasma to the internal magnetic field structure of the associated prominence. We made multi-wavelength observations with high spatial resolution and high cadence using SDO/AIA, the Interface Region Imaging Spectrograph (IRIS) spectrograph, and the Hinode/Solar Optical Telescope (SOT) instrument. Along with spectropolarimetry provided by the Télescope Héliographique pour l’Etude du Magnétisme et des Instabilités Solaires telescope we have coverage of both optically thick emission lines and magnetic field information. AIA reveals that the two legs of the prominence are strongly absorbing structures which look like they are rotating, or oscillating in the plane of the sky. The two prominence legs, which are both very bright in Ca ii (SOT), are not visible in the IRIS Mg ii slit-jaw images. This is explained by the large optical thickness of the structures in Mg ii, which leads to reversed profiles, and hence to lower integrated intensities at these locations than in the surroundings. Using lines formed at temperatures lower than 1 MK, we measure relatively low Doppler shifts on the order of ±10 km s{sup −1} in the tornado-like structure. Between the two legs we see loops in Mg ii, with material flowing from one leg to the other, as well as counterstreaming. It is difficult to interpret our data as showing two rotating, vertical structures that are unrelated to the loops. This kind of “tornado” scenario does not fit with our observations. The magnetic field in the two legs of the prominence is found to be preferentially horizontal.

  19. Magnetic field and radiative transfer modelling of a quiescent prominence

    Czech Academy of Sciences Publication Activity Database

    Gunár, S.; Schwartz, Pavol; Dudík, J.; Schmieder, B.; Heinzel, Petr; Jurčák, Jan

    2014-01-01

    Roč. 567, July (2014), A123/1-A123/16 ISSN 0004-6361 R&D Projects: GA ČR GAP209/12/0906; GA ČR GAP209/12/0287 Grant - others:SAV(SK) VEGA2/0108/12 Institutional support: RVO:67985815 Keywords : Sun: filaments * prominence * magnetic fields Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.378, year: 2014

  20. Ten Prominent Host Proteases in Plant-Pathogen Interactions

    Directory of Open Access Journals (Sweden)

    Emma L. Thomas

    2018-02-01

    Full Text Available Proteases are enzymes integral to the plant immune system. Multiple aspects of defence are regulated by proteases, including the hypersensitive response, pathogen recognition, priming and peptide hormone release. These processes are regulated by unrelated proteases residing at different subcellular locations. In this review, we discuss 10 prominent plant proteases contributing to the plant immune system, highlighting the diversity of roles they perform in plant defence.

  1. Timing of fluoride intake and dental fluorosis on late-erupting permanent teeth.

    Science.gov (United States)

    Bhagavatula, Pradeep; Levy, Steven M; Broffitt, Barbara; Weber-Gasparoni, Karin; Warren, John J

    2016-02-01

    Very few studies have examined the relationship between timing of fluoride intake and development of dental fluorosis on late-erupting permanent teeth using period-specific fluoride intake information. This study examined this relationship using longitudinal fluoride intake information from the Iowa Fluoride Study. Participants' fluoride exposure and intake (birth to 10 years of age) from water, beverages, selected food products, dietary fluoride supplements, and fluoride toothpaste was collected using questionnaires sent to parents at 3- and 4- month intervals from birth to 48 months of age and every 6 months thereafter. Three trained and calibrated examiners used the Fluorosis Risk Index (FRI) categories to assess 16 late-erupting teeth among 465 study participants. A tooth was defined as having definitive fluorosis if any of the zones on that tooth had an FRI score of 2 or 3. Participants with questionable fluorosis were excluded from analyses. Descriptive and logistic regression analyses were performed to assess the importance of fluoride intake during different time periods. Most dental fluorosis in the study population was mild, with only four subjects (1%) having severe fluorosis (FRI Score 3). The overall prevalence of dental fluorosis was 27.8%. Logistic regression analyses showed that fluoride intake from each of the individual years from age 2 to 8 plays an important role in determining the risk of dental fluorosis for most late-erupting permanent teeth. The strongest association for fluorosis on the late-erupting permanent teeth was with fluoride intake during the sixth year of life. Late-erupting teeth may be susceptible to fluorosis for an extended period from about age 2 to 8. Although not as visually prominent as the maxillary central incisors, some of the late-erupting teeth are esthetically important and this should be taken into consideration when making recommendations about dosing of fluoride intake. © 2015 John Wiley & Sons A/S. Published by

  2. Prominence and tornado dynamics observed with IRIS and THEMIS

    Science.gov (United States)

    Schmieder, Brigitte; Levens, Peter; Labrosse, Nicolas; Mein, Pierre; Lopez Ariste, Arturo; Zapior, Maciek

    2017-08-01

    Several prominences were observed during campaigns in September 2013 and July 2014 with the IRIS spectrometer and the vector magnetograph THEMIS (Tenerife). SDO/AIA and IRIS provided images and spectra of prominences and tornadoes corresponding to different physical conditions of the transition region between the cool plasma and the corona. The vector magnetic field was derived from THEMIS observations by using the He D3 depolarisation due to the magnetic field. The inversion code (PCA) takes into account the Hanle and Zeeman effects and allows us to compute the strength and the inclination of the magnetic field which is shown to be mostly horizontal in prominences as well as in tornadoes. Movies from SDO/AIA in 304 A and Hinode/SOT in Ca II show the highly dynamic nature of the fine structures. From spectra in Mg II and Si IV lines provided by IRIS and H-alpha observed by the Multi-channel Subtractive Double Pass (MSDP) spectrograph in the Meudon Solar Tower we derived the Doppler shifts of the fine structures and reconstructed the 3D structure of tornadoes. We conclude that the apparent rotation of AIA tornadoes is due to large-scale quasi-periodic oscillations of the plasma along more or less horizontal magnetic structures.

  3. Prominent EMA 'dots' in tumour-induced Bergmann gliosis.

    Science.gov (United States)

    Gelpi, Ellen; Bombi, Josep A; Martinez-Saez, Elena; Caral, Luis; Ribalta, Teresa

    2014-02-01

    To describe an unusual pattern of epithelial membrane antigen (EMA) immunoreactivity in highly proliferative human Bergmann glia. An immunohistochemical study was performed of postmortem cerebellar tissue from 18 adult patients with cerebellar damage of various aetiologies and 15 biopsies of diverse adult and paediatric cerebellar tumours. We observed marked proliferation of Bergmann glia with unusual prominent dot-like cytoplasmic EMA immunoreactivity in a case with extensive leptomeningeal sarcomatosis. Similar staining was not observed in association with other types of cerebellar pathology, except for other neoplastic conditions, such as leptomeningeal carcinomatosis, adult medulloblastoma, and pilocytic astrocytoma in children. At an ultrastructural level, the index case showed prominent endoplasmic reticulum with some intermediate filaments and lipofuscin granules, but no structures related to cilia or microvilli were observed. We consider that prominent EMA dots in Bergmann glia might represent excessive activation induced by an overlying leptomeningeal tumour that stimulates the expression of early developmental antigens. This observation suggests modulation of the glial phenotype when exposed to a neoplastic microenvironment that, in turn, might influence the regenerative potential of Bergmann glia. © 2013 John Wiley & Sons Ltd.

  4. The pattern of circumferential and radial eruptive fissures on the volcanoes of Fernandina and Isabela islands, Galapagos

    Science.gov (United States)

    Chadwick, W.W.; Howard, K.A.

    1991-01-01

    Maps of the eruptive vents on the active shield volcanoes of Fernandina and Isabela islands, Galapagos, made from aerial photographs, display a distinctive pattern that consists of circumferential eruptive fissures around the summit calderas and radial fissures lower on the flanks. On some volcano flanks either circumferential or radial eruptions have been dominant in recent time. The location of circumferential vents outside the calderas is independent of caldera-related normal faults. The eruptive fissures are the surface expression of dike emplacement, and the dike orientations are interpreted to be controlled by the state of stress in the volcano. Very few subaerial volcanoes display a pattern of fissures similar to that of the Galapagos volcanoes. Some seamounts and shield volcanoes on Mars morphologically resemble the Galapagos volcanoes, but more specific evidence is needed to determine if they also share common structure and eruptive style. ?? 1991 Springer-Verlag.

  5. Temperature reconstruction and volcanic eruption signal from tree-ring width and maximum latewood density over the past 304 years in the southeastern Tibetan Plateau.

    Science.gov (United States)

    Li, Mingqi; Huang, Lei; Yin, Zhi-Yong; Shao, Xuemei

    2017-11-01

    This study presents a 304-year mean July-October maximum temperature reconstruction for the southeastern Tibetan Plateau based on both tree-ring width and maximum latewood density data. The reconstruction explained 58% of the variance in July-October maximum temperature during the calibration period (1958-2005). On the decadal scale, we identified two prominent cold periods during AD 1801-1833 and 1961-2003 and two prominent warm periods during AD 1730-1800 and 1928-1960, which are consistent with other reconstructions from the nearby region. Based on the reconstructed temperature series and volcanic eruption chronology, we found that most extreme cold years were in good agreement with major volcanic eruptions, such as 1816 after the Tambora eruption in 1815. Also, clusters of volcanic eruptions probably made the 1810s the coldest decade in the past 300 years. Our results indicated that fingerprints of major volcanic eruptions can be found in the reconstructed temperature records, while the responses of regional climate to these eruption events varied in space and time in the southeastern Tibetan Plateau.

  6. RADIO DIAGNOSTICS OF ELECTRON ACCELERATION SITES DURING THE ERUPTION OF A FLUX ROPE IN THE SOLAR CORONA

    Energy Technology Data Exchange (ETDEWEB)

    Carley, Eoin P.; Gallagher, Peter T. [Astrophysics Research Group, School of Physics, Trinity College Dublin, Dublin 2 (Ireland); Vilmer, Nicole, E-mail: eoin.carley@obspm.fr [LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité, 5 place Jules Janssen, F-92195 Meudon (France)

    2016-12-10

    Electron acceleration in the solar corona is often associated with flares and the eruption of twisted magnetic structures known as flux ropes. However, the locations and mechanisms of such particle acceleration during the flare and eruption are still subject to much investigation. Observing the exact sites of particle acceleration can help confirm how the flare and eruption are initiated and how they evolve. Here we use the Atmospheric Imaging Assembly to analyze a flare and erupting flux rope on 2014 April 18, while observations from the Nançay Radio Astronomy Facility allow us to diagnose the sites of electron acceleration during the eruption. Our analysis shows evidence of a pre-formed flux rope that slowly rises and becomes destabilized at the time of a C-class flare, plasma jet, and the escape of ≳75 keV electrons from the rope center into the corona. As the eruption proceeds, continued acceleration of electrons with energies of ∼5 keV occurs above the flux rope for a period over 5 minutes. At the flare peak, one site of electron acceleration is located close to the flare site, while another is driven by the erupting flux rope into the corona at speeds of up to 400 km s{sup −1}. Energetic electrons then fill the erupting volume, eventually allowing the flux rope legs to be clearly imaged from radio sources at 150–445 MHz. Following the analysis of Joshi et al. (2015), we conclude that the sites of energetic electrons are consistent with flux rope eruption via a tether cutting or flux cancellation scenario inside a magnetic fan-spine structure. In total, our radio observations allow us to better understand the evolution of a flux rope eruption and its associated electron acceleration sites, from eruption initiation to propagation into the corona.

  7. Thermal vesiculation during volcanic eruptions.

    Science.gov (United States)

    Lavallée, Yan; Dingwell, Donald B; Johnson, Jeffrey B; Cimarelli, Corrado; Hornby, Adrian J; Kendrick, Jackie E; von Aulock, Felix W; Kennedy, Ben M; Andrews, Benjamin J; Wadsworth, Fabian B; Rhodes, Emma; Chigna, Gustavo

    2015-12-24

    Terrestrial volcanic eruptions are the consequence of magmas ascending to the surface of the Earth. This ascent is driven by buoyancy forces, which are enhanced by bubble nucleation and growth (vesiculation) that reduce the density of magma. The development of vesicularity also greatly reduces the 'strength' of magma, a material parameter controlling fragmentation and thus the explosive potential of the liquid rock. The development of vesicularity in magmas has until now been viewed (both thermodynamically and kinetically) in terms of the pressure dependence of the solubility of water in the magma, and its role in driving gas saturation, exsolution and expansion during decompression. In contrast, the possible effects of the well documented negative temperature dependence of solubility of water in magma has largely been ignored. Recently, petrological constraints have demonstrated that considerable heating of magma may indeed be a common result of the latent heat of crystallization as well as viscous and frictional heating in areas of strain localization. Here we present field and experimental observations of magma vesiculation and fragmentation resulting from heating (rather than decompression). Textural analysis of volcanic ash from Santiaguito volcano in Guatemala reveals the presence of chemically heterogeneous filaments hosting micrometre-scale vesicles. The textures mirror those developed by disequilibrium melting induced via rapid heating during fault friction experiments, demonstrating that friction can generate sufficient heat to induce melting and vesiculation of hydrated silicic magma. Consideration of the experimentally determined temperature and pressure dependence of water solubility in magma reveals that, for many ascent paths, exsolution may be more efficiently achieved by heating than by decompression. We conclude that the thermal path experienced by magma during ascent strongly controls degassing, vesiculation, magma strength and the effusive

  8. Myth and catastrophic reality: using cosmogonic mythology to identify cosmic impacts and massive plinian eruptions in holocene South America.

    Energy Technology Data Exchange (ETDEWEB)

    Masse, W. B. (William Bruce)

    2004-01-01

    Major natural catastrophes (e.g., 'universal' floods, fire, darkness, and sky falling down) are prominently reflected in traditional South American creation myths, cosmology, religion, and worldview. We are now beginning to recognize that cosmogonic myths represent a rich and largely untapped data set concerning the most dramatic natural events and processes experienced by each cultural group during the past several thousand years. Observational details regarding specific catastrophes are encoded in myth storylines, typically cast in terms of supernatural characters and actions. Not only are the myths amenable to scientific analysis, but also some sets of myths encode multiple catastrophes in meaningful relative chronological order. The present study considers more than 4200 myths, including more than 260 'universal' catastrophe myths from cultural groups throughout South America. These myths are examined in light of available geological, paleoenvironmental, archeological, and documentary evidence. Our analysis reveals three possible ultra-plinian volcanic eruptions, two in Columbia and the other in the Gran Chaco, the latter likely associated with a poorly dated late Holocene eruption of Nuevo Mundo in central Bolivia. Our analysis also identifies a set of traditions likely linked with the well-known Campo del Cielo iron meteorite impact in northern Argentina originally hypothesized to have occurred around 4000 years ago. Intriguingly, these traditions strongly suggest that the Campo del Cielo impact triggered widespread mass fires in the Gran Chaco region and possibly in the Brazilian Highlands. Several other potential cosmic impacts, distinct from Campo del Cielo, are hinted at in the mythology of other locations in South America. The numerous catastrophe myths in the Gran Chaco region exhibit the most coherent chronological sequence of any South American region. The sequence begins with a 'Great Flood,' by far the most widespread

  9. Volcanic hazards from Bezymianny- and Bandai-type eruptions

    Science.gov (United States)

    Siebert, L.; Glicken, H.; Ui, T.

    1987-01-01

    Major slope failures are a significant degradational process at volcanoes. Slope failures and associated explosive eruptions have resulted in more than 20 000 fatalities in the past 400 years; the historic record provides evidence for at least six of these events in the past century. Several historic debris avalanches exceed 1 km3 in volume. Holocene avalanches an order of magnitude larger have traveled 50-100 km from the source volcano and affected areas of 500-1500 km2. Historic eruptions associated with major slope failures include those with a magmatic component (Bezymianny type) and those solely phreatic (Bandai type). The associated gravitational failures remove major segments of the volcanoes, creating massive horseshoe-shaped depressions commonly of caldera size. The paroxysmal phase of a Bezymianny-type eruption may include powerful lateral explosions and pumiceous pyroclastic flows; it is often followed by construction of lava dome or pyroclastic cone in the new crater. Bandai-type eruptions begin and end with the paroxysmal phase, during which slope failure removes a portion of the edifice. Massive volcanic landslides can also occur without related explosive eruptions, as at the Unzen volcano in 1792. The main potential hazards from these events derive from lateral blasts, the debris avalanche itself, and avalanche-induced tsunamis. Lateral blasts produced by sudden decompression of hydrothermal and/or magmatic systems can devastate areas in excess of 500km2 at velocities exceeding 100 m s-1. The ratio of area covered to distance traveled for the Mount St. Helens and Bezymianny lateral blasts exceeds that of many pyroclastic flows or surges of comparable volume. The potential for large-scale lateral blasts is likely related to the location of magma at the time of slope failure and appears highest when magma has intruded into the upper edifice, as at Mount St. Helens and Bezymianny. Debris avalanches can move faster than 100 ms-1 and travel tens of

  10. Large explosive basaltic eruptions at Katla volcano, Iceland: Fragmentation, grain size and eruption dynamics

    Science.gov (United States)

    Schmith, Johanne; Höskuldsson, Ármann; Holm, Paul Martin; Larsen, Guðrún

    2018-04-01

    Katla volcano in Iceland produces hazardous large explosive basaltic eruptions on a regular basis, but very little quantitative data for future hazard assessments exist. Here details on fragmentation mechanism and eruption dynamics are derived from a study of deposit stratigraphy with detailed granulometry and grain morphology analysis, granulometric modeling, componentry and the new quantitative regularity index model of fragmentation mechanism. We show that magma/water interaction is important in the ash generation process, but to a variable extent. By investigating the large explosive basaltic eruptions from 1755 and 1625, we document that eruptions of similar size and magma geochemistry can have very different fragmentation dynamics. Our models show that fragmentation in the 1755 eruption was a combination of magmatic degassing and magma/water-interaction with the most magma/water-interaction at the beginning of the eruption. The fragmentation of the 1625 eruption was initially also a combination of both magmatic and phreatomagmatic processes, but magma/water-interaction diminished progressively during the later stages of the eruption. However, intense magma/water interaction was reintroduced during the final stages of the eruption dominating the fine fragmentation at the end. This detailed study of fragmentation changes documents that subglacial eruptions have highly variable interaction with the melt water showing that the amount and access to melt water changes significantly during eruptions. While it is often difficult to reconstruct the progression of eruptions that have no quantitative observational record, this study shows that integrating field observations and granulometry with the new regularity index can form a coherent model of eruption evolution.

  11. Plasma Evolution within an Erupting Coronal Cavity

    Science.gov (United States)

    Long, David M.; Harra, Louise K.; Matthews, Sarah A.; Warren, Harry P.; Lee, Kyoung-Sun; Doschek, George A.; Hara, Hirohisa; Jenkins, Jack M.

    2018-03-01

    Coronal cavities have previously been observed to be associated with long-lived quiescent filaments and are thought to correspond to the associated magnetic flux rope. Although the standard flare model predicts a coronal cavity corresponding to the erupting flux rope, these have only been observed using broadband imaging data, restricting an analysis to the plane-of-sky. We present a unique set of spectroscopic observations of an active region filament seen erupting at the solar limb in the extreme ultraviolet. The cavity erupted and expanded rapidly, with the change in rise phase contemporaneous with an increase in nonthermal electron energy flux of the associated flare. Hot and cool filamentary material was observed to rise with the erupting flux rope, disappearing suddenly as the cavity appeared. Although strongly blueshifted plasma continued to be observed flowing from the apex of the erupting flux rope, this outflow soon ceased. These results indicate that the sudden injection of energy from the flare beneath forced the rapid eruption and expansion of the flux rope, driving strong plasma flows, which resulted in the eruption of an under-dense filamentary flux rope.

  12. Synthetic differential emission measure curves of prominence fine structures. II. The SoHO/SUMER prominence of 8 June 2004

    Czech Academy of Sciences Publication Activity Database

    Gunár, Stanislav; Parenti, S.; Anzer, U.; Heinzel, Petr; Vial, J. C.

    2011-01-01

    Roč. 535, November (2011), A122/1-A122/11 ISSN 0004-6361 R&D Projects: GA ČR GP205/09/P554; GA ČR GA205/09/1705; GA ČR GAP209/10/1706 Institutional research plan: CEZ:AV0Z10030501 Keywords : Sun * filaments * prominences Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.587, year: 2011

  13. Properties of the prominence magnetic field and plasma distributions as obtained from 3D whole-prominence fine structure modeling

    Czech Academy of Sciences Publication Activity Database

    Gunár, Stanislav; Mackay, D. H.

    2016-01-01

    Roč. 592, August (2016), A60/1-A60/10 ISSN 0004-6361 R&D Projects: GA ČR(CZ) GA16-17586S EU Projects: European Commission(XE) 328138 - COMBINED MHD AND RT Institutional support: RVO:67985815 Keywords : Sun * filaments * prominences Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.378, year: 2014

  14. Mini-filaments - small-scale analogues of solar eruptive events?

    Science.gov (United States)

    Denker, Carsten; Tritschler, Alexandra

    2009-04-01

    Mini-filaments are a small-scale phenomenon of the solar chromosphere, which frequently occur across the entire disk (see e.g. Wang, Li, Denker, et al. 2000). They share a variety of characteristics with their larger-scale cousins and may serve as a proxy for more complex systems. They play an important role in the energy and mass supply to the corona. In the case of small-scale eruptive filaments, only a single, small-scale loop system is involved. Furthermore, they are supported by simple magnetic field configurations (see Livi, Wang & Martin 1985), either magnetic bipoles or well-defined multipoles, easing their theoretical description. Since mini-filaments are small (just a few tens of seconds of arc) but highly dynamic (eruptions can occur within just a few minutes), they are an ideal target for high-resolution two-dimensional spectroscopy. We present a preliminary analysis of two-dimensional Hα spectroscopic data accompanied by broad-band speckle-restored images to demonstrate that chromospheric small-scale phenomena can serve as building blocks for our understanding of solar eruptive events such as filament/prominence eruptions and even coronal mass ejections (CMEs).

  15. Eruptions with short run-up times: review of controlling factors inspired by the unexpected eruption of Calbuco volcano, April 2015, (Southern Andes)

    Science.gov (United States)

    Lara, L.; Esperger, S.

    2015-12-01

    Signs of unrest are usually detected in active volcanoes before the onset of eruptions. However, a few eruptions start suddenly without evident precursory activity or very short run-up time. The latter poses a challenge to volcano observatories regarding the capability to issue early warnings. Calbuco (42°S, Southern Andes) explosive event in April 2015 is a recent case where clear signs of unrest were detected shortly before the eruption of an andesitic magma (57% SiO2). In fact, although isolated low magnitude VT events were recorded 2 months before, the base level was only disturbed 3 hours before by an emergent seismic swarm of MCalbuco erupted after 54 years of quiescence and no ground deformation was detected by InSAR or ground-based methods before the eruption. This short precursory activity is comparable to run-up times observed in basaltic to andesitic volcanoes. Previous authors have proposed a relationship between repose and run-up times. Repose time seems to be related with dynamics of plumbing systems (recharge and storage) and thus depends on the magma viscosity and hence magma composition. Others have shown that correlation between repose and run-up times is dependent of volcano typology. Here we expand the catalog and consider other factors as the crustal thickness, physical properties of the country rocks, depth of magma chambers and tectonic regime for all the reported eruptions with existing information. Our findings show that eruptions preceded by an extremely short unrest period occur mostly under conditions of favorable (tectonically-controlled) magma pathways unclamping, even in high-silica systems with large repose times.

  16. Reconstructing the deadly eruptive events of 1790 CE at Kīlauea Volcano, Hawai‘i

    Science.gov (United States)

    Swanson, Don; Weaver, Samantha J; Houghton, Bruce F.

    2014-01-01

    A large number of people died during an explosive eruption of Kīlauea Volcano in 1790 CE. Detailed study of the upper part of the Keanakāko‘i Tephra has identified the deposits that may have been responsible for the deaths. Three successive units record shifts in eruption style that agree well with accounts of the eruption based on survivor interviews 46 yr later. First, a wet fall of very fine, accretionary-lapilli–bearing ash created a “cloud of darkness.” People walked across the soft deposit, leaving footprints as evidence. While the ash was still unconsolidated, lithic lapilli fell into it from a high eruption column that was seen from 90 km away. Either just after this tephra fall or during its latest stage, pulsing dilute pyroclastic density currents, probably products of a phreatic eruption, swept across the western flank of Kīlauea, embedding lapilli in the muddy ash and crossing the trail along which the footprints occur. The pyroclastic density currents were most likely responsible for the fatalities, as judged from the reported condition and probable location of the bodies. This reconstruction is relevant today, as similar eruptions will probably occur in the future at Kīlauea and represent its most dangerous and least predictable hazard.

  17. Signs and Symptoms of Primary Tooth Eruption: A Meta-analysis.

    Science.gov (United States)

    Massignan, Carla; Cardoso, Mariane; Porporatti, André Luís; Aydinoz, Secil; Canto, Graziela De Luca; Mezzomo, Luis Andre Mendonça; Bolan, Michele

    2016-03-01

    Symptoms associated with the primary tooth eruption have been extensively studied but it is still controversial. To assess the occurrence of local and systemic signs and symptoms during primary tooth eruption. Latin American and Caribbean Health Sciences, PubMed, ProQuest, Scopus, and Web of Science were searched. A partial gray literature search was taken by using Google Scholar and the reference lists of the included studies were scanned. Observational studies assessing the association of eruption of primary teeth with local and systemic signs and symptoms in children aged 0 to 36 months were included. Two authors independently collected the information from the selected articles. Information was crosschecked and confirmed for its accuracy. A total of 1179 articles were identified, and after a 2-phase selection, 16 studies were included. Overall prevalence of signs and symptoms occurring during primary tooth eruption in children between 0 and 36 months was 70.5% (total sample = 3506). Gingival irritation (86.81%), irritability (68.19%), and drooling (55.72%) were the most frequent ones. Different general symptoms were considered among studies. Some studies presented lack of confounding factors, no clear definition of the diagnostics methods, use of subjective measures and long intervals between examinations. There is evidence of the occurrence of signs and symptoms during primary tooth eruption. For body temperature analyses, eruption could lead to a rise in temperature, but it was not characterized as fever. Copyright © 2016 by the American Academy of Pediatrics.

  18. Strongly gliding harmonic tremor during the 2009 eruption of Redoubt Volcano

    Science.gov (United States)

    Hotovec, Alicia J.; Prejean, Stephanie G.; Vidale, John E.; Gomberg, Joan S.

    2013-01-01

    During the 2009 eruption of Redoubt Volcano, Alaska, gliding harmonic tremor occurred prominently before six nearly consecutive explosions during the second half of the eruptive sequence. The fundamental frequency repeatedly glided upward from harmonic tremor is not uncommon at volcanoes, tremor at such high frequencies is a rare observation. These frequencies approach or exceed the plausible upper limits of many models that have been suggested for volcanic tremor. We also analyzed the behavior of a swarm of repeating earthquakes that immediately preceded the first instance of pre-explosion gliding harmonic tremor. We find that these earthquakes share several traits with upward gliding harmonic tremor, and favor the explanation that the gliding harmonic tremor at Redoubt Volcano is created by the superposition of increasingly frequent and regular, repeating stick–slip earthquakes through the Dirac comb effect.

  19. Eruption and degassing dynamics of the major August 2015 Piton de la Fournaise eruption

    Science.gov (United States)

    Di Muro, Andrea; Arellano, Santiago; Aiuppa, Alessandro; Bachelery, Patrick; Boudoire, Guillaume; Coppola, Diego; Ferrazzini, Valerie; Galle, Bo; Giudice, Gaetano; Gurioli, Lucia; Harris, Andy; Liuzzo, Marco; Metrich, Nicole; Moune, Severine; Peltier, Aline; Villeneuve, Nicolas; Vlastelic, Ivan

    2016-04-01

    Piton de la Fournaise (PdF) shield volcano is one of the most active basaltic volcanoes in the World with one eruption every nine months, on average. This frequent volcanic activity is broadly bimodal, with frequent small volume, short lived eruptions (volume summit to proximal eruptions of relatively evolved cotectic magmas and relatively long repose periods (up to 3.5 years between 2010 and 2014). The August 2015 eruption was the first large (45±15 Mm3) and long lasting (2 months) eruption since 2007 and the only event to be fully monitored by the new gas geochemical network of Piton de la Fournaise volcanological observatory (DOAS, MultiGaS, diffuse CO2 soil emissions). Regular lava and tephra sampling was also performed for geochemical and petrological analysis. The eruption was preceded by a significant increase in CO2 soil emissions at distal soil stations (ca. 15 km from the summit), with CO2 enrichment also being recorded at summit low temperature fumaroles. Eruptive products were spectacularly zoned, with plagioclase and pyroxene being abundant in the early erupted products and olivine being the main phase in the late-erupted lavas. Total gas emissions at the eruptive vent underwent a decrease during the first half of the eruption and then an increase, mirroring the time evolution of magma discharge rate (from 5-10 m3/s in September to 15-30 m3/s in late-October) and the progressive change in magma composition. In spite of significant evolution in magma and gas output, CO2/SO2 ratios in high temperature gases remained quite low (pulse of deep magma. While erupted magma and high temperature gases were mostly provided by the shallow part of the system, distal sites and summit low temperature fumaroles recorded a deeper triggering mechanism.

  20. Eruptive history of the Dieng Mountains region, central Java, and potential hazards from future eruptions

    Science.gov (United States)

    Miller, C. Dan; Sushyar, R.; ,; Hamidi, S.

    1983-01-01

    The Dieng Mountains region consists of a complex of late Quaternary to recent volcanic stratocones, parasitic vents, and explosion craters. Six age groups of volcanic centers, eruptive products, and explosion craters are recognized in the region based on their morphology, degree of dissection, stratigraphic relationships, and degree of weathering. These features range in age from tens of thousands of years to events that have occurred this century. No magmatic eruptions have occurred in the Dieng Mountains region for at least several thousand years; volcanic activity during this time interval has consisted of phreatic eruptions and non-explosive hydrothermal activity. If future volcanic events are similar to those of the last few thousand years, they will consist of phreatic eruptions, associated small hot mudflows, emission of suffocating gases, and hydrothermal activity. Future phreatic eruptions may follow, or accompany, periods of increased earthquake activity; the epicenters for the seismicity may suggest where eruptive activity will occur. Under such circumstances, the populace within several kilometers of a potential eruption site should be warned of a possible eruption, given instructions about what to do in the event of an eruption, or temporarily evacuated to a safer location.

  1. Giant Plagioclase Basalts, eruption rate versus time

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 111; Issue 4. Giant Plagioclase Basalts, eruption rate versus time: Response to Sheth's comments and some additional thoughts. Gautam Sen. Volume 111 Issue 4 December 2002 pp 487-488 ...

  2. Polymorphous light eruption - some interesting aspects

    International Nuclear Information System (INIS)

    Corrales-Padilla, H.; Dominguez-Soto, L.; Hojyo-Tomoka, M.T.; Londono, F.; Vargas-Ocampo, F.

    1979-01-01

    A study of polymorphous light eruption (PLE) is Latin America is reported. The clinical lesions, the course, histopathology, differential diagnosis, pathogenesis, treatment and systemic photoprotection are discussed. Treatment with ultraviolet radiation is included. (C.F.)

  3. The onset of the volcanism in the Ciomadul Volcanic Dome Complex (Eastern Carpathians): Eruption chronology and magma type variation

    Science.gov (United States)

    Molnár, Kata; Harangi, Szabolcs; Lukács, Réka; Dunkl, István; Schmitt, Axel K.; Kiss, Balázs; Garamhegyi, Tamás; Seghedi, Ioan

    2018-04-01

    Combined zircon U-Th-Pb and (U-Th)/He dating was applied to refine the eruption chronology of the last 2 Myr for the andesitic and dacitic Pilişca volcano and Ciomadul Volcanic Dome Complex (CVDC), the youngest volcanic area of the Carpathian-Pannonian region, located in the southernmost Harghita, eastern-central Europe. The proposed eruption ages, which are supported also by the youngest zircon crystallization ages, are much younger than the previously determined K/Ar ages. By dating every known eruption center in the CVDC, repose times between eruptive events were also accurately determined. Eruption of the andesite at Murgul Mare (1865 ± 87 ka) and dacite of the Pilişca volcanic complex (1640 ± 37 ka) terminated an earlier pulse of volcanic activity within the southernmost Harghita region, west of the Olt valley. This was followed by the onset of the volcanism in the CVDC, which occurred after several 100s kyr of eruptive quiescence. At ca. 1 Ma a significant change in the composition of erupted magma occurred from medium-K calc-alkaline compositions to high-K dacitic (Baba-Laposa dome at 942 ± 65 ka) and shoshonitic magmas (Malnaş and Bixad domes; 964 ± 46 ka and 907 ± 66 ka, respectively). Noteworthy, eruptions of magmas with distinct chemical compositions occurred within a restricted area, a few km from one another. These oldest lava domes of the CVDC form a NNE-SSW striking tectonic lineament along the Olt valley. Following a brief (ca. 100 kyr) hiatus, extrusion of high-K andesitic magma continued at Dealul Mare (842 ± 53 ka). After another ca. 200 kyr period of quiescence two high-K dacitic lava domes extruded (Puturosul: 642 ± 44 ka and Balvanyos: 583 ± 30 ka). The Turnul Apor lava extrusion occurred after a ca. 200 kyr repose time (at 344 ± 33 ka), whereas formation of the Haramul Mic lava dome (154 ± 16 ka) represents the onset of the development of the prominent Ciomadul volcano. The accurate determination of eruption dates shows that the

  4. Perceptions of Social Responsibility of Prominent Animal Welfare Groups.

    Science.gov (United States)

    Widmar, Nicole J Olynk; Morgan, Carissa J; Croney, Candace C

    2018-01-01

    Nonhuman animal welfare is an increasingly important component of consumer expectations of corporate social responsibility (CSR). The extent to which prominent animal welfare or protection organizations may influence people's perceptions of food industry CSR may be related to an organization's perceived social responsibility. Data from an online survey of 300 U.S. residents were used to explore relationships between demographics/lifestyle choices and perceptions of prominent animal welfare organizations (using best-worst scaling methodology). Overall, the American Society for the Prevention of Cruelty to Animals was perceived to be the most socially responsible organization analyzed, followed by the Humane Society of the United States and the American Humane Association (AHA). Results suggest that the perceived social responsibility of animal protection organizations in this study was not strongly linked to personally (financially) supporting them, with 2 exceptions: the perceptions of People for the Ethical Treatment of Animals and AHA. Improved understanding of the perception of animal welfare or protection organizations can inform decision making by organizations interested in furthering animal welfare causes.

  5. Eruption disturbances in Japanese children and adolescents

    OpenAIRE

    Noda, Tadashi; Takagi, Masamichi; Hayashi-Sakai, Sachiko; Taguchi, Yo

    2006-01-01

    The aims of this report were to determine the nature of eruption disturbances and to establish the pattern of managment tor these teeth in a group of Japanese children and adolescents. Data were collected trom the clinical records of patients in the Pediatric Dental Clinic of Niigata University Medical and Dental Hospital. There were 700 patients (364 males and 336 femalse) and 748 teeth (26 primary teeth and 722 permanent teeth) who were treated for eruption disturbances between 1979 and 200...

  6. ERUPTION PATTERN OF PERMANENT TEETH -IN TANZANIA ...

    African Journals Online (AJOL)

    was visible in the oral vacity. Generally permanent teeth erupted earlier in girls than in boys. The differences were 0.1 - 0.2 years for incisors and first molars, 0.2 - 0.4 years for canines and premolars and 0.3 - 0.5 years for second molars. Except for the second premolars, mandibular teeth erupted earlier than the maxillary in ...

  7. Eruption reported in Aleutian Islands

    Science.gov (United States)

    On November 29, an airplane pilot reported the start of an eruption on Mount Westdahl on Unimak Island in the Aleutian Islands (54.52°N, 164.65°W), according to the Smithsonian Institution's Global Volcanism Network. The pilot sighted an ash plume rising to more than 7 km altitude at 1705 local time ( = UT-11 hours). The main portion of the plume, at about 5 km altitude, extended 80-95 km east-northeast by 0930 the next morning.About noon, U.S. Coast Guard pilots observed a NE-SW fissure vent 5-8 km long, with at least one active lava flow traveling down the east flank. The area surrounding the vent was ash-covered, and increased runoff and possible mudflows were observed. Vigorous steam and ash emission was visible throughout the day from False Pass (90 km NE), which experienced a very fine dusting of ash. A strong sulfur odor at False Pass lasted into the night, and similar odors were reported by pilots up to several hundred kilometers inland. No ashfall has been reported in Cold Bay (145 km NE).

  8. Excitation of atmospheric oscillations by volcanic eruptions

    Science.gov (United States)

    Kanamori, Hiroo; Mori, Jim; Harkrider, David G.

    1994-11-01

    We investigated the mechanism of atmospheric oscillations with periods of about 300 s which were observed for the 1991 Pinatubo and the 1982 El Chichon eruptions. Two distinct spectral peaks, at T = 270 and 230 s for the Pinatubo eruption and at T = 195 and 266 s for the El Chichon eruptions, have been reported. We found similar oscillations for the 1980 Mount St. Helens and the 1883 Krakatoa eruptions. To explain these observations, we investigated excitation problems for two types of idealized sources, 'mass injection' and 'energy injection' sources, placed in an isothermal atmosphere. In general, two modes of oscillations, 'acoustic' and 'gravity' modes, can be excited. For realistic atmospheric parameters, the acoustic and gravity modes have a period of 275 and 304 s, respectively. For a realistic time history of eruption, atmospheric oscillations with an amplitude of 50 to 100 Pa (0.5 to 1 mbar) can be excited by an energy injection source with a total energy of 10(exp 17) J. This result is consistent with the observations and provides a physical basis for interpretation of atmospheric oscillations excited by volcanic eruptions.

  9. Reduced cooling following future volcanic eruptions

    Science.gov (United States)

    Hopcroft, Peter O.; Kandlbauer, Jessy; Valdes, Paul J.; Sparks, R. Stephen J.

    2017-11-01

    Volcanic eruptions are an important influence on decadal to centennial climate variability. Large eruptions lead to the formation of a stratospheric sulphate aerosol layer which can cause short-term global cooling. This response is modulated by feedback processes in the earth system, but the influence from future warming has not been assessed before. Using earth system model simulations we find that the eruption-induced cooling is significantly weaker in the future state. This is predominantly due to an increase in planetary albedo caused by increased tropospheric aerosol loading with a contribution from associated changes in cloud properties. The increased albedo of the troposphere reduces the effective volcanic aerosol radiative forcing. Reduced sea-ice coverage and hence feedbacks also contribute over high-latitudes, and an enhanced winter warming signal emerges in the future eruption ensemble. These findings show that the eruption response is a complex function of the environmental conditions, which has implications for the role of eruptions in climate variability in the future and potentially in the past.

  10. The 2010 Eruption of Merapi Volcano, Java, Indonesia: Petrological Insights into Magma Dynamics and Eruptive Behaviour

    Science.gov (United States)

    Gertisser, R.; Handley, H.; Preece, K.; Reagan, M.; Berlo, K.; Barclay, J.; Herd, R.

    2012-04-01

    The violent eruption of Merapi volcano (Central Java) that started on 26 October 2010 was the volcano's largest since 1872 and the deadliest event since 1930. Before 2010, Merapi's more recent (historical) eruptive activity was repeatedly characterised by periods of slow lava dome extrusion punctuated by gravitational dome failures, generating small-volume pyroclastic density currents (PDCs) with runout distances of typically less than 10 km. The unforeseen, large-magnitude events in 2010 were unusual in many respects: (1) the eruption was short-lived and started with an explosive phase that was not preceded by a lava dome at the surface; (2) between 31 October and 4 November, a lava dome appeared and grew rapidly within the summit crater, exceeding growth rates observed at the peak of the penultimate eruption in 2006 by a factor of ~ 22; (3) during the most vigorous eruptive phase on 5 November, at least one PDC travelled more than 15 km (more than twice the distance of the largest flows in 2006) beyond the summit along the Gendol river valley, causing widespread devastation on Merapi's south flank; (4) in a late phase of the eruption, pumice-rich PDCs were produced, forming a thin veneer on top of the deposits of the largest PDCs from 5 November; (5) ash emissions from sustained eruption columns resulted in ash fall tens of kilometres from the volcano, affecting, amongst other areas, the volcano's western slopes and the city of Yogyakarta ~ 25 km to the south; and (6) the total deposited volume in 2010, based on provisional estimates, may have been ~ 10 times higher than that of other recent eruptions. Here we report and present new geochemical, Sr-Nd-O isotope and U-series data for the volcanic products (lava dome fragments, magmatic inclusions, scoria, pumice and ash) from various stages of the 2010 eruption of Merapi. These data are discussed in the context of other recent to historical, typically less explosive, dome-forming eruptions to elucidate the driving

  11. Experimental Constraints on Forecasting the Location of Volcanic Eruptions from Pre-eruptive Surface Deformation

    Directory of Open Access Journals (Sweden)

    Frank Guldstrand

    2018-02-01

    Full Text Available Volcanic eruptions pose a threat to lives and property when volcano flanks and surroundings are densely populated. The local impact of an eruption depends firstly on its location, whether it occurs near a volcano summit, or down on the flanks. Then forecasting, with a defined accuracy, the location of a potential, imminent eruption would significantly improve the assessment and mitigation of volcanic hazards. Currently, the conventional volcano monitoring methods based on the analysis of surface deformation assesses whether a volcano may erupt but are not implemented to locate imminent eruptions in real time. Here we show how surface deformation induced by ascending eruptive feeders can be used to forecast the eruption location through a simple geometrical analysis. Our analysis builds on the results of 33 scaled laboratory experiments simulating the emplacement of viscous magma intrusions in a brittle, cohesive Coulomb crust under lithostatic stress conditions. The intrusion-induced surface deformation was systematically monitored at high spatial and temporal resolution. In all the experiments, surface deformation preceding the eruptions resulted in systematic uplift, regardless of the intrusion shape. The analysis of the surface deformation patterns leads to the definition of a vector between the center of the uplifted area and the point of maximum uplift, which systematically acted as a precursor to the eruption's location. The temporal evolution of this vector indicated the direction in which the subsequent eruption would occur and ultimately the location itself, irrespective of the feeder shapes. Our findings represent a new approach on how surface deformation on active volcanoes that are not in active rifts could be analysed and used prior to an eruption with a real potential to improve hazard mitigation.

  12. Infantile epidermolytic ichthyosis with prominent maternal palmoplantar keratoderma.

    Science.gov (United States)

    Austin Smith, Wallace; Cope, Austin; Fernandez, Martin; Parekh, Palak

    2016-04-18

    Epidermolytic Ichthyosis (EI) is a rare autosomal dominant genodermatosis. Although an inherited disorder, 50% of cases represent novel mutations. This disorder presents as a bullous disease in newborns progressing to a lifelong ichthyotic skin disorder.  Other manifestations include palmoplantar keratoderma (PPK).  EI results from mutations in the keratin 1 and keratin 10 genes. Phenotypic variability is seen in affected individuals based on the genotypic mutation.  We present a mother and her newborn son with EI and prominent PPK in the mother, which also developed in the child at a few months of age.  Genotype analysis was performed on the newborn child who was found to harbor a mutation in the keratin 1 gene. This family demonstrates the phenotypic expression of PPK associated with keratin 1 gene mutations and illustrates the importance of genotype-phenotypecorrelation in this disorder.

  13. Clinical Mass Spectrometry: Achieving Prominence in Laboratory Medicine

    Energy Technology Data Exchange (ETDEWEB)

    Annesley, Thomas M.; Cooks, Robert G.; Herold, David A.; Hoofnagle, Andrew N.

    2016-01-04

    Each year the journal Clinical Chemistry publishes a January special issue on a topic that is relevant to the laboratory medicine community. In January 2016 the topic is mass spectrometry, and the issue is entitled “Clinical Mass Spectrometry: Achieving Prominence in Laboratory Medicine”. One popular feature in our issues is a Q&A on a topic, clearly in this case mass spectrometry. The journal is assembling a panel of 5-6 experts from various areas of mass spectrometry ranging from instrument manufacturing to practicing clinical chemists. Dick Smith is one of the scientist requested to participate in this special issue Q&A on Mass Spectrometry. The Q&A Transcript is attached

  14. Vaccination elicits a prominent acute phase response in horses.

    Science.gov (United States)

    Andersen, Susanne A; Petersen, Henrik H; Ersbøll, Annette K; Falk-Rønne, Jørgen; Jacobsen, Stine

    2012-02-01

    European and American guidelines for vaccination against tetanus and influenza in horses recommend annual and annual/semi-annual vaccinations, respectively, against the two pathogens. Too-frequent vaccination may, however, have adverse effects, among other things because an inflammatory response is elicited with subsequent alterations in homeostasis. The objective of the study was to compare the acute phase response (APR) in 10 horses following administration of two different types of vaccines, namely, an inactivated Immune Stimulating COMplex (ISCOM) vaccine and a live recombinant vector vaccine. Blood was sampled before and after vaccination to measure levels of serum amyloid A (SAA), fibrinogen, white blood cell counts (WBC) and iron. Vaccination induced a prominent APR with increased WBC, elevated blood levels of SAA and fibrinogen, and decreased serum iron concentrations. The ISCOM vaccine caused significantly (Phorse owners about convalescence after vaccination. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Three-Dimensional Morphology of a Coronal Prominence Cavity

    Science.gov (United States)

    Gibson, S. E.; Kucera, T. A.; Rastawicki, D.; Dove, J.; deToma, G.; Hao, J.; Hill, S.; Hudson, H. S.; Marque, C.; McIntosh, P. S.; hide

    2010-01-01

    We present a three-dimensional density model of coronal prominence cavities, and a morphological fit that has been tightly constrained by a uniquely well-observed cavity. Observations were obtained as part of an International Heliophysical Year campaign by instruments from a variety of space- and ground-based observatories, spanning wavelengths from radio to soft-X-ray to integrated white light. From these data it is clear that the prominence cavity is the limb manifestation of a longitudinally-extended polar-crown filament channel, and that the cavity is a region of low density relative to the surrounding corona. As a first step towards quantifying density and temperature from campaign spectroscopic data, we establish the three-dimensional morphology of the cavity. This is critical for taking line-of-sight projection effects into account, since cavities are not localized in the plane of the sky and the corona is optically thin. We have augmented a global coronal streamer model to include a tunnel-like cavity with elliptical cross-section and a Gaussian variation of height along the tunnel length. We have developed a semi-automated routine that fits ellipses to cross-sections of the cavity as it rotates past the solar limb, and have applied it to Extreme Ultraviolet Imager (EUVI) observations from the two Solar Terrestrial Relations Observatory (STEREO) spacecraft. This defines the morphological parameters of our model, from which we reproduce forward-modeled cavity observables. We find that cavity morphology and orientation, in combination with the viewpoints of the observing spacecraft, explains the observed variation in cavity visibility for the east vs. west limbs

  16. A FLUX ROPE ERUPTION TRIGGERED BY JETS

    International Nuclear Information System (INIS)

    Guo Juan; Zhang Hongqi; Deng Yuanyong; Lin Jiaben; Su Jiangtao; Liu Yu

    2010-01-01

    We present an observation of a filament eruption caused by recurrent chromospheric plasma injections (surges/jets) on 2006 July 6. The filament eruption was associated with an M2.5 two-ribbon flare and a coronal mass ejection (CME). There was a light bridge in the umbra of the main sunspot of NOAA 10898; one end of the filament was terminated at the region close to the light bridge, and recurrent surges were observed to be ejected from the light bridge. The surges occurred intermittently for about 8 hr before the filament eruption, and finally a clear jet was found at the light bridge to trigger the filament eruption. We analyzed the evolutions of the relative darkness of the filament and the loaded mass by the continuous surges quantitatively. It was found that as the occurrence of the surges, the relative darkness of the filament body continued growing for about 3-4 hr, reached its maximum, and kept stable for more than 2 hr until it erupted. If suppose 50% of the ejected mass by the surges could be trapped by the filament channel, then the total loaded mass into the filament channelwill be about 0.57x10 16 g with a momentum of 0.57x10 22 g cm s -1 by 08:08 UT, which is a non-negligible effect on the stability of the filament. Based on the observations, we present a model showing the important role that recurrent chromospheric mass injection play in the evolution and eruption of a flux rope. Our study confirms that the surge activities can efficiently supply the necessary material for some filament formation. Furthermore, our study indicates that the continuous mass with momentum loaded by the surge activities to the filament channel could make the filament unstable and cause it to erupt.

  17. Characterize Eruptive Processes at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Valentine, G.

    2001-01-01

    This Analysis/Model Report (AMR), ''Characterize Eruptive Processes at Yucca Mountain, Nevada'', presents information about natural volcanic systems and the parameters that can be used to model their behavior. This information is used to develop parameter-value distributions appropriate for analysis of the consequences of volcanic eruptions through a potential repository at Yucca Mountain. Many aspects of this work are aimed at resolution of the Igneous Activity Key Technical Issue (KTI) as identified by the Nuclear Regulatory Commission (NRC 1998, p. 3), Subissues 1 and 2, which address the probability and consequence of igneous activity at the proposed repository site, respectively. Within the framework of the Disruptive Events Process Model Report (PMR), this AMR provides information for the calculations in two other AMRs ; parameters described herein are directly used in calculations in these reports and will be used in Total System Performance Assessment (TSPA). Compilation of this AMR was conducted as defined in the Development Plan, except as noted. The report begins with considerations of the geometry of volcanic feeder systems, which are of primary importance in predicting how much of a potential repository would be affected by an eruption. This discussion is followed by one of the physical and chemical properties of the magmas, which influences both eruptive styles and mechanisms for interaction with radioactive waste packages. Eruptive processes including the ascent velocity of magma at depth, the onset of bubble nucleation and growth in the rising magmas, magma fragmentation, and velocity of the resulting gas-particle mixture are then discussed. The duration of eruptions, their power output, and mass discharge rates are also described. The next section summarizes geologic constraints regarding the interaction between magma and waste packages. Finally, they discuss bulk grain size produced by relevant explosive eruptions and grain shapes

  18. Infrasound characterization of some Yellowstone geysers' eruptions

    Science.gov (United States)

    Quezada-Reyes, A.; Johnson, J.

    2012-12-01

    Geysers are springs that intermittently erupt hot water and steam. As with volcanoes, infrasonic airwaves produced by different geysers provide information about the processes that occur near the nozzle, such as the amount of fluid released during eruptive episodes. The aim of this study was to investigate acoustic sources from different geyser behaviors observed at Lone Star, Sawmill and Great Fountain geysers, Yellowstone National Park, Wyoming. Acoustic signal were measured by arrays of microphones deployed around Lone Star and Great Fountain geysers between August 9th to 14th, 2011, and during one hour on August 16th, 2011 at Sawmill Geyser. Infrasound was analyzed with coincident video recordings to quantify and compare the pressure fields generated during explosive phases at the three geysers. We propose that the periodic infrasound recorded at Sawmill, and dominated by energy at 1 to 40 Hz, is generated by: 1) steam-filled bubble oscillations, and 2) subsequent bursting at the free surface resulting in a violent steam and water discharge. At Lone Star geyser, where ~18 m/s eruption jets endure for about 30 minutes, sound is dominated by higher frequency infrasound and audio-band signal evolving from 20 - 60 Hz to 40 - 85 Hz. We suggest that the infrasound tremor amplitudes are related to the transition of the erupted two-phase mixture from mostly water (low acoustic radiation) to steam (high acoustic radiation). At Great Fountain we observed three explosive bursts of water and steam during the last stage on the August 11 eruption with bi-modal infrasound pulses of up to 0.7 Pa-m. We model these pulses as volumetric sound sources and infer up to 32 m3 of fluid ejection. The variety of recordings reflect the variety of eruption mechanisms at the different geyser systems. Better understanding of the mechanisms of geyser infrasound radiation may help us to understand infrasound analogues at erupting silicic volcanoes, which are considerably more difficult to

  19. Volcanic Processes, and Possible Precursors of Eruptions at Etna and Stromboli Volcanoes Revealed by Thermal Surveys

    Science.gov (United States)

    Calvari, S.

    2007-05-01

    also been used to calculate the effusion rate, the most important parameter to estimate maximum lava flow length, and also to detect ash plumes on Etna in good weather conditions. However, the three most recent eruptions on Etna, occurred on 2004-05, July 2006 and August-December 2006, did not show evident thermal anomalies on the summit craters before the opening of eruptive fissures. Thus, the role of thermal anomalies and their meaning should be compared to and discussed with other geophysical data in order to understand when and if these data can be used to forecast eruptions.

  20. Onset of a basaltic explosive eruption from Kīlauea’s summit in 2008: Chapter 19

    Science.gov (United States)

    Carey, Rebecca J.; Swavely, Lauren; Swanson, Don; Houghton, Bruce F.; Orr, Tim R.; Elias, Tamar; Sutton, Andrew; Carey, Rebecca; Cayol, Valérie; Poland, Michael P.; Weis, Dominique

    2015-01-01

    The onset of a basaltic eruption at the summit of Kīlauea volcano in 2008 is recorded in the products generated during the first three weeks of the eruption and suggests an evolution of both the physical properties of the magma and also lava lake levels and vent wall stability. Ash componentry and the microtextures of the early erupted lapilli products reveal that the magma was largely outgassed, perhaps in the preceding weeks to months. An increase in the juvenile:lithic ratio and size of ash collected from March 23 to April 3 records an increasing level of the magma within the conduit. After April 3 until the explosive eruption of April 9, a trend of decreasing juvenile:lithic ratio suggests that vent wall collapses were more frequent, possibly because lava level increased and destabilized the overhanging wall [Orr et al. 2013]. Despite increasing lake height, the microtextural characteristics of the lapilli suggest that the outgassed end-member was still being tapped between March 26 and April 8. The April 9 rockfall triggered an explosive eruption that produced a new component in the eruption deposits not seen in the preceding weeks; microvesicular juvenile lapilli, the first evidence of an actively vesiculating magma. Two additional dense end-member pyroclast types were also erupted during the April 9 explosion, likely related to outgassed magma with longer residence times than the microvesicular magma. We link these pyroclasts to a stagnant viscous crust at the top of the magma column or to convecting, downwelling magma. Our study of ash componentry and the textures of juvenile lapilli suggests that the April 9 explosive event effectively cleared the conduit of largely outgassed magma. The degassing processes during this eruption are complex and varied: in the period of persistent degassing during March 26-April 8 small resident bubbles at shallow levels in the lava lake were coupled to the magma whereas large bubbles ascended, expanded and fragmented

  1. Guided tooth eruption: Comparison of open and closed eruption techniques in labially impacted maxillary canines

    Directory of Open Access Journals (Sweden)

    S M londhe

    2014-01-01

    Full Text Available Background: After third molars, the maxillary canines are the most commonly impacted permanent teeth and one-third of these are labial impactions. Impacted canines often require orthodontic guidance in the eruption. This study was conducted to assess the posttreatment results of surgically exposed and orthodontically aligned labially impacted maxillary canines comparing two different surgical techniques. Materials and Methods: The study was conducted in two phases, a surgical phase and an orthodontic phase. In surgical phase, events during surgical exposure and recovery of 31 patients with labially impacted maxillary canine were recorded. Patients were managed with open and closed eruption technique. The assessment included comparison of two techniques of surgical exposure, postoperative pain, mobility, vitality, periodontal health, level of impaction, and duration of orthodontic treatment. Results: The postoperative recovery was longer after open eruption than close eruption technique (P = 0.000. Postoperative pain experienced by patients was similar, but regression of pain was faster in closed eruption technique. The mean surgical time for open eruption technique was lesser when compared with closed eruption technique (P = 0.000. The total duration of orthodontic treatment was directly dependent upon the level of impaction, with deeper level of impaction having longer duration of orthodontic treatment. The mobility and vitality of guided canine was similar in both techniques. Conclusion: The closed eruption technique was a longer surgical procedure, but the postoperative pain regression was faster. The duration of orthodontic treatment was longer with deeper level of impaction. The closed eruption surgical techniques provide better periodontal tissues around the guided erupted teeth.

  2. Experimental constraints on forecasting the location of volcanic eruptions from pre-eruptive surface deformation

    Science.gov (United States)

    Guldstrand, Frank; Galland, Olivier; Hallot, Erwan; Burchardt, Steffi

    2018-02-01

    Volcanic eruptions pose a threat to lives and property when volcano flanks and surroundings are densely populated. The local impact of an eruption depends firstly on its location, whether it occurs near a volcano summit, or down on the flanks. Then forecasting, with a defined accuracy, the location of a potential, imminent eruption would significantly improve the assessment and mitigation of volcanic hazards. Currently, the conventional volcano monitoring methods based on the analysis of surface deformation assesses whether a volcano may erupt but are not implemented to locate imminent eruptions in real time. Here we show how surface deformation induced by ascending eruptive feeders can be used to forecast the eruption location through a simple geometrical analysis. Our analysis builds on the results of 33 scaled laboratory experiments simulating magma intrusions in a brittle crust, during which the intrusion-induced surface deformation was systematically monitored at high spatial and temporal resolution. In all the experiments, surface deformation preceding the eruptions resulted in systematic uplift, regardless of the intrusion shape. The analysis of the surface deformation patterns leads to the definition of a vector between the centre of the uplifted zone and the point of maximum uplift, which systematically acted as a precursor to the eruption’s location. The temporal evolution of this vector indicated the direction in which the subsequent eruption would occur and ultimately the location itself, irrespective of the feeder shapes. Our findings represent a new approach on how surface deformation on active volcanoes could be analysed and used prior to an eruption with a real potential to improve hazard mitigation.

  3. Thermal signature, eruption style, and eruption evolution at Pele and Pillan on Io

    Science.gov (United States)

    Davies, A.G.; Keszthelyi, L.P.; Williams, D.A.; Phillips, C.B.; McEwen, A.S.; Lopes, R.M.C.; Smythe, W.D.; Kamp, L.W.; Soderblom, L.A.; Carlson, R.W.

    2001-01-01

    The Galileo spacecraft has been periodically monitoring volcanic activity on Io since June 1996, making it possible to chart the evolution of individual eruptions. We present results of coanalysis of Near-Infrared Mapping Spectrometer (NIMS) and solid-state imaging (SSI) data of eruptions at Pele and Pillan, especially from a particularly illuminating data set consisting of mutually constraining, near-simultaneous NIMS and SSI observations obtained during orbit C9 in June 1997. The observed thermal signature from each hot spot, and the way in which the thermal signature changes with time, tightly constrains the possible styles of eruption. Pele and Pillan have very different eruption styles. From September 1996 through May 1999, Pele demonstrates an almost constant total thermal output, with thermal emission spectra indicative of a long-lived, active lava lake. The NIMS Pillan data exhibit the thermal signature of a "Pillanian" eruption style, a large, vigorous eruption with associated open channel, or sheet flows, producing an extensive flow field by orbit C10 in September 1997. The high mass eruption rate, high liquidus temperature (at least 1870 K) eruption at Pillan is the best candidate so far for an active ultramafic (magnesium-rich, "komatiitic") flow on Io, a style of eruption never before witnessed. The thermal output per unit area from Pillan is, however, consistent with the emplacement of large, open-channel flows. Magma temperature at Pele is ~1600 K. If the magma temperature is 1600 K, it suggests a komatiitic-basalt composition. The power output from Pele is indicative of a magma volumetric eruption rate of ~250 to 340 m3 s-1. Although the Pele lava lake is considerably larger than its terrestrial counterparts, the power and mass fluxes per unit area are similar to active terrestrial lava lakes. Copyright 2001 by the American Geophysical Union.

  4. Eruption precursors: Manifestations and strategies for detection

    Science.gov (United States)

    Poland, Michael; Pritchard, Matthew

    2017-04-01

    The past several decades have seen a rapid increase in volcano monitoring and modeling capabilities. Diverse arrays of instrument networks can detect a variety of pre-, co-, and post-eruptive phenomena, and remote sensing observations are available across a range of spatial, temporal, and spectral resolutions. A growing class of models, based on the physics of magmatic systems, are making use of these expanding datastreams, providing probabilistic assessments of such parameters as magma supply, volatile content, and eruption duration. To what extent, however, do these developments heighten our ability to identify eruption precursors? The advent of better data and new models provides an opportunity to reexamine our understanding of pre-eruption unrest, as well as our ability to detect and recognize it as such. An idealized model of the buildup to a volcanic eruption might include magma ascent from a deep source region and accumulation in the mid- to upper crust in the preceding months to years. The process might be manifested by surface inflation and deep long-period earthquakes, and accompanied by an increase in CO2 emissions. As magma continues to accumulate, distal volcano-tectonic earthquakes may result as stress builds on nearby faults, H2S emissions may increase as sulfur in a shallow reservoir is hydrolyzed by groundwater, and fumarole and spring temperatures may increase and show changes in chemistry. In the days to hours before an eruption, sudden changes in the rate and style of earthquakes (including repeating earthquakes and tremor) and deformation may occur as the magma reservoir ruptures and magma moves laterally or vertically. Phreatic eruptions might result as ascending magma comes into contact with groundwater, and SO2 emissions might increase as the path between the magma and surface dries out. How often does such a sequence actually occur? Relatively few volcanoes are comprehensively monitored prior to obvious expressions of unrest, so this is not

  5. Characterization of volcanic deposits and geoarchaeological studies from the 1815 eruption of Tambora volcano

    Directory of Open Access Journals (Sweden)

    Igan Supriatman Sutawidjaja

    2014-06-01

    Full Text Available http://dx.doi.org/10.17014/ijog.vol1no1.20066aThe eruption of Tambora volcano on the island of Sumbawa in 1815 is generally considered as the largest and the most violent volcanic event in recorded history. The cataclysmic eruption occurred on 11 April 1815 was initiated by Plinian eruption type on 5 April and killed more than 90,000 people on Sumbawa and nearby Lombok. The type plinian eruptions occurred twice and ejected gray pumice and ash, to form stratified deposits as thick as 40-150 cm on the slopes and mostly distributed over the district west of the volcano. Following this, at about 7 pm, on 11 April the first pyroclastic surge was generated and progressively became greater extending to almost whole direction, mainly to the north, west, and south districts from the eruption center. The deadliest volcanic eruption buried ancient villages by pyroclastic surge and flow deposits in almost intact state, thus preserving important archaeological evidence for the period. High preservation in relatively stable conditions and known date of the eruptions provide approximate dating for the archaeological remains. Archaeological excavations on the site uncovered a variety of remains were relieved by ground penetrating radar (GPR to map structural remains of the ancient villages under the pyroclastic surge and flow deposits. These traverses showed that GPR could define structures as deep as 10 m (velocity 0.090 m/ns and could accurately map the thickness of the stratified volcanic deposits in the Tambora village area.    

  6. Vapor transfer prior to the October 2004 eruption of Mount St. Helens, Washington

    Science.gov (United States)

    Kent, A.J.R.; Blundy, J.; Cashman, K.V.; Copper, K.M.; Donnelly, C.; Pallister, J.S.; Reagan, M.; Rowe, M.C.; Thornber, C.R.

    2007-01-01

    Dome lavas from the 2004 eruption of Mount St. Helens show elevated Li contents in plagioclase phenocrysts at the onset of dome growth in October 2004. These cannot be explained by variations in plagioclase-melt partitioning, but require elevated Li contents in coexisting melt, a fact confirmed by measurements of Li contents as high as 207 ??g/g in coexisting melt inclusions. Similar Li enrichment has been observed in material erupted prior to and during the climactic May 1980 eruption, and is likewise best explained via pre-eruptive transfer of an exsolved alkali-rich vapor phase derived from deeper within the magma transport system. Unlike 1980, however, high Li samples from 2004 show no evidence of excess (210Pb)/(226 Ra), implying that measurable Li enrichments may occur despite significant differences in the timing and/or extent of magmatic degassing. Diffusion modeling shows that Li enrichment occurred within -1 yr before eruption, and that magma remained Li enriched until immediately before eruption and cooling. This short flux time and the very high Li contents in ash produced by phreatomagmatic activity prior to the onset of dome extrusion suggest that vapor transfer and accumulation were associated with initiation of the current eruption. Overall, observation of a high Li signature in both 1980 and 2004 dacites indicates that Li enrichment may be a relatively common phenomenon, and may prove useful for petrologic monitoring of Mount St. Helens and other silicic volcanoes. Lithium diffusion is also sufficiently rapid to constrain vapor transfer on similar time scales to short-lived radionuclides. ?? 2007 Geological Society of America.

  7. Clinico-Epidemiological Comparison of Delusion-Prominent and Hallucination-Prominent Clinical Subgroups of Paranoid Schizophrenia.

    Science.gov (United States)

    Kreinin, Anatoly; Krishtul, Vladimir; Kirsh, Zvi; Menuchin, Michael

    2015-01-01

    Though hallucinations and delusions are prominent basic impairments in schizophrenia, reports of the relationship between hallucinatory and delusional symptoms among schizophrenia patients are scant. To examine the epidemiological and clinical differences between mainly hallucinatory and mainly delusional subgroups of paranoid schizophrenia patients. One hundred schizophrenia patients, paranoid type, were recruited. In a cross-sectional study, participants were divided into Mainly Hallucinatory (H) and Mainly Delusional (D) subgroups. Demographic variables were compared and clinical characteristics were evaluated using the Scale for the Assessment of Positive Symptoms, the Scale for the Assessment of Negative Symptoms, and the Clinical Global Impression Scale. The Quality-of-Life Enjoyment and Satisfaction Questionnaire-18 was used to assess quality of life. Clinically, the H group was more heterogeneous as expressed by the broader range of scores that described the clinical picture of patients in that subgroup (in 43 of 78 variables, 55.13%) and similar ranges of scores (31 of 78 variables, 39.74%) for patients in the D group. Duration of hospitalization was significantly longer in group H than in group D (p=0.047). There was no statistically significant difference between the H and D subgroups in demographic characteristics. There are distinct epidemiological and clinical differences between the H and D subgroups, with more severe positive and negative symptoms and greater functional impairment in the H group. Paranoid schizophrenia patients with prominent hallucinations have poorer prognosis and need intensive therapeutic rehabilitation beginning with onset-of-illness. Further genetic studies and comparisons of fMRI and/or PET findings are warranted to investigate additional distinctive characteristics of these subgroups.

  8. Russian eruption warning systems for aviation

    Science.gov (United States)

    Neal, C.; Girina, O.; Senyukov, S.; Rybin, A.; Osiensky, J.; Izbekov, P.; Ferguson, G.

    2009-01-01

    More than 65 potentially active volcanoes on the Kamchatka Peninsula and the Kurile Islands pose a substantial threat to aircraft on the Northern Pacific (NOPAC), Russian Trans-East (RTE), and Pacific Organized Track System (PACOTS) air routes. The Kamchatka Volcanic Eruption Response Team (KVERT) monitors and reports on volcanic hazards to aviation for Kamchatka and the north Kuriles. KVERT scientists utilize real-time seismic data, daily satellite views of the region, real-time video, and pilot and field reports of activity to track and alert the aviation industry of hazardous activity. Most Kurile Island volcanoes are monitored by the Sakhalin Volcanic Eruption Response Team (SVERT) based in Yuzhno-Sakhalinsk. SVERT uses daily moderate resolution imaging spectroradiometer (MODIS) satellite images to look for volcanic activity along this 1,250-km chain of islands. Neither operation is staffed 24 h per day. In addition, the vast majority of Russian volcanoes are not monitored seismically in real-time. Other challenges include multiple time-zones and language differences that hamper communication among volcanologists and meteorologists in the US, Japan, and Russia who share the responsibility to issue official warnings. Rapid, consistent verification of explosive eruptions and determination of cloud heights remain significant technical challenges. Despite these difficulties, in more than a decade of frequent eruptive activity in Kamchatka and the northern Kuriles, no damaging encounters with volcanic ash from Russian eruptions have been recorded. ?? Springer Science+Business Media B.V. 2009.

  9. Identifying the volcanic eruption depicted in a neolithic painting at Çatalhöyük, Central Anatolia, Turkey.

    Directory of Open Access Journals (Sweden)

    Axel K Schmitt

    Full Text Available A mural excavated at the Neolithic Çatalhöyük site (Central Anatolia, Turkey has been interpreted as the oldest known map. Dating to ∼6600 BCE, it putatively depicts an explosive summit eruption of the Hasan Dağı twin-peaks volcano located ∼130 km northeast of Çatalhöyük, and a birds-eye view of a town plan in the foreground. This interpretation, however, has remained controversial not least because independent evidence for a contemporaneous explosive volcanic eruption of Hasan Dağı has been lacking. Here, we document the presence of andesitic pumice veneer on the summit of Hasan Dağı, which we dated using (U-Th/He zircon geochronology. The (U-Th/He zircon eruption age of 8.97±0.64 ka (or 6960±640 BCE; uncertainties 2σ overlaps closely with (14C ages for cultural strata at Çatalhöyük, including level VII containing the "map" mural. A second pumice sample from a surficial deposit near the base of Hasan Dağı records an older explosive eruption at 28.9±1.5 ka. U-Th zircon crystallization ages in both samples range from near-eruption to secular equilibrium (>380 ka. Collectively, our results reveal protracted intrusive activity at Hasan Dağı punctuated by explosive venting, and provide the first radiometric ages for a Holocene explosive eruption which was most likely witnessed by humans in the area. Geologic and geochronologic lines of evidence thus support previous interpretations that residents of Çatalhöyük artistically represented an explosive eruption of Hasan Dağı volcano. The magmatic longevity recorded by quasi-continuous zircon crystallization coupled with new evidence for late-Pleistocene and Holocene explosive eruptions implicates Hasan Dağı as a potential volcanic hazard.

  10. Identifying the Volcanic Eruption Depicted in a Neolithic Painting at Çatalhöyük, Central Anatolia, Turkey

    Science.gov (United States)

    Schmitt, Axel K.; Danišík, Martin; Aydar, Erkan; Şen, Erdal; Ulusoy, İnan; Lovera, Oscar M.

    2014-01-01

    A mural excavated at the Neolithic Çatalhöyük site (Central Anatolia, Turkey) has been interpreted as the oldest known map. Dating to ∼6600 BCE, it putatively depicts an explosive summit eruption of the Hasan Dağı twin-peaks volcano located ∼130 km northeast of Çatalhöyük, and a birds-eye view of a town plan in the foreground. This interpretation, however, has remained controversial not least because independent evidence for a contemporaneous explosive volcanic eruption of Hasan Dağı has been lacking. Here, we document the presence of andesitic pumice veneer on the summit of Hasan Dağı, which we dated using (U-Th)/He zircon geochronology. The (U-Th)/He zircon eruption age of 8.97±0.64 ka (or 6960±640 BCE; uncertainties 2σ) overlaps closely with 14C ages for cultural strata at Çatalhöyük, including level VII containing the “map” mural. A second pumice sample from a surficial deposit near the base of Hasan Dağı records an older explosive eruption at 28.9±1.5 ka. U-Th zircon crystallization ages in both samples range from near-eruption to secular equilibrium (>380 ka). Collectively, our results reveal protracted intrusive activity at Hasan Dağı punctuated by explosive venting, and provide the first radiometric ages for a Holocene explosive eruption which was most likely witnessed by humans in the area. Geologic and geochronologic lines of evidence thus support previous interpretations that residents of Çatalhöyük artistically represented an explosive eruption of Hasan Dağı volcano. The magmatic longevity recorded by quasi-continuous zircon crystallization coupled with new evidence for late-Pleistocene and Holocene explosive eruptions implicates Hasan Dağı as a potential volcanic hazard. PMID:24416270

  11. The influence of eruption season on the global aerosol evolution and radiative impact of tropical volcanic eruptions

    Directory of Open Access Journals (Sweden)

    M. Toohey

    2011-12-01

    Full Text Available Simulations of tropical volcanic eruptions using a general circulation model with coupled aerosol microphysics are used to assess the influence of season of eruption on the aerosol evolution and radiative impacts at the Earth's surface. This analysis is presented for eruptions with SO2 injection magnitudes of 17 and 700 Tg, the former consistent with estimates of the 1991 Mt. Pinatubo eruption, the later a near-"super eruption". For each eruption magnitude, simulations are performed with eruptions at 15° N, at four equally spaced times of year. Sensitivity to eruption season of aerosol optical depth (AOD, clear-sky and all-sky shortwave (SW radiative flux is quantified by first integrating each field for four years after the eruption, then calculating for each cumulative field the absolute or percent difference between the maximum and minimum response from the four eruption seasons. Eruption season has a significant influence on AOD and clear-sky SW radiative flux anomalies for both eruption magnitudes. The sensitivity to eruption season for both fields is generally weak in the tropics, but increases in the mid- and high latitudes, reaching maximum values of ~75 %. Global mean AOD and clear-sky SW anomalies show sensitivity to eruption season on the order of 15–20 %, which results from differences in aerosol effective radius for the different eruption seasons. Smallest aerosol size and largest cumulative impact result from a January eruption for Pinatubo-magnitude eruption, and from a July eruption for the near-super eruption. In contrast to AOD and clear-sky SW anomalies, all-sky SW anomalies are found to be insensitive to season of eruption for the Pinatubo-magnitude eruption experiment, due to the reflection of solar radiation by clouds in the mid- to high latitudes. However, differences in all-sky SW anomalies between eruptions in different seasons are significant for the larger eruption magnitude, and the ~15 % sensitivity to

  12. Postglacial eruptive history and geochemistry of Semisopochnoi volcano, western Aleutian Islands, Alaska

    Science.gov (United States)

    Coombs, Michelle L.; Larsen, Jessica F.; Neal, Christina A.

    2018-02-14

    Semisopochnoi Island, located in the Rat Islands group of the western Aleutian Islands and Aleutian volcanic arc, is a roughly circular island composed of scattered volcanic vents, the prominent caldera of Semisopochnoi volcano, and older, ancestral volcanic rocks. The oldest rocks on the island are gently radially dipping lavas that are the remnants of a shield volcano and of Ragged Top, which is an eroded stratocone southeast of the current caldera. None of these oldest rocks have been dated, but they all are likely Pleistocene in age. Anvil Peak, to the caldera’s north, has the morphology of a young stratocone and is latest Pleistocene to early Holocene in age. The oldest recognized Holocene deposits are those of the caldera-forming eruption, which produced the 7- by 6-km caldera in the center of the island, left nonwelded ignimbrite in valleys below the edifice, and left welded ignimbrite high on its flanks. The caldera-forming eruption produced rocks showing a range of intermediate whole-rock compositions throughout the eruption sequence, although a majority of clasts analyzed form a fairly tight cluster on SiO2-variation diagrams at 62.9 to 63.4 weight percent SiO2. This clustering of compositions at about 63 weight percent SiO2 includes black, dense, obsidian-like clasts, as well as tan, variably oxidized, highly inflated pumice clasts. The best estimate for the timing of the eruption is from a soil dated at 6,920±60 14C years before present underlying a thin facies of the ignimbrite deposit on the island’s north coast. Shortly after the caldera-forming eruption, two scoria cones on the northwest flank of the volcano outside the caldera, Ringworm crater and Threequarter Cone, simultaneously erupted small volumes of andesite.The oldest intracaldera lavas, on the floor of the caldera, are andesitic to dacitic, but are mostly covered by younger lavas and tephras. These intracaldera lavas include the basaltic andesites of small Windy cone, as well as the

  13. No evidence for shallow shear motion on the Mat Fault, a prominent ...

    Indian Academy of Sciences (India)

    and is flanked by the Bay of Bengal sediments to the west and Shan Plateau to the east (Fitch 1972;. Le Dain et al. ... Shan Plateau and joins into the Andaman sea rift system which finally joins the Sumatra Fault. System in ..... 2008 Subduction of the Indian lithosphere beneath the. Tibetan Plateau and Burma; Earth Planet.

  14. Tidal Control of Jet Eruptions on Enceladus as Observed by Cassini ISS between 2005 and 2007

    Science.gov (United States)

    Hurford, T. A.; Helfenstein, P.; Spitale, J. N.

    2012-01-01

    Observations of Enceladus have revealed active jets of material erupting from cracks on its south polar surface. It has previously been proposed that diurnal tidal stress, driven by Enceladus' orbital eccentricity, may actively produce surface movement along these cracks daily and thus may regulate when eruptions occur. Our analysis of the stress on jet source regions identified in Cassini ISS images reveals tidal stress as a plausible controlling mechanism of jet activity. However, the evidence available in the published and preliminary observations of jet activity between 2005 and 2007 may not be able to solidify the link between tidal stress and eruptions from fissures. Ongoing, far more comprehensive analyses based on recent, much higher resolution jetting observations have the potential to prove otherwise.

  15. Studies of the chronological course of wisdom tooth eruption in a Black African population.

    Science.gov (United States)

    Olze, Andreas; van Niekerk, Piet; Schulz, Ronald; Schmeling, Andreas

    2007-09-01

    The importance of forensic age estimation in living subjects has grown over the last few years. In dental age estimation, tooth eruption is a parameter of developmental morphology that can be analyzed by either clinical examination or by evaluation of dental X-rays. In the present study, we determined the stage of wisdom tooth eruption in 410 male and 106 female Black South African subjects of known age (12-26 years) based on radiological evidence from 516 conventional orthopantomograms. Four eruption stages were determined (no emergence, alveolar emergence, gingival emergence, complete emergence). Statistical scores were determined for the individual stages separately for both sexes. The data presented here can be utilized for forensic estimation of the minimum and most probable ages of investigated persons.

  16. Eruption of Alaska volcano breaks historic pattern

    Science.gov (United States)

    Larsen, Jessica; Neal, Christina A.; Webley, Peter; Freymueller, Jeff; Haney, Matthew; McNutt, Stephen; Schneider, David; Prejean, Stephanie; Schaefer, Janet; Wessels, Rick L.

    2009-01-01

    In the late morning of 12 July 2008, the Alaska Volcano Observatory (AVO) received an unexpected call from the U.S. Coast Guard, reporting an explosive volcanic eruption in the central Aleutians in the vicinity of Okmok volcano, a relatively young (~2000-year-old) caldera. The Coast Guard had received an emergency call requesting assistance from a family living at a cattle ranch on the flanks of the volcano, who reported loud "thunder," lightning, and noontime darkness due to ashfall. AVO staff immediately confirmed the report by observing a strong eruption signal recorded on the Okmok seismic network and the presence of a large dark ash cloud above Okmok in satellite imagery. Within 5 minutes of the call, AVO declared the volcano at aviation code red, signifying that a highly explosive, ash-rich eruption was under way.

  17. Eruption of Alaska Volcano Breaks Historic Pattern

    Science.gov (United States)

    Larsen, Jessica; Neal, Christina; Webley, Peter; Freymueller, Jeff; Haney, Matthew; McNutt, Stephen; Schneider, David; Prejean, Stephanie; Schaefer, Janet; Wessels, Rick

    2009-05-01

    In the late morning of 12 July 2008, the Alaska Volcano Observatory (AVO) received an unexpected call from the U.S. Coast Guard, reporting an explosive volcanic eruption in the central Aleutians in the vicinity of Okmok volcano, a relatively young (˜2000-year-old) caldera. The Coast Guard had received an emergency call requesting assistance from a family living at a cattle ranch on the flanks of the volcano, who reported loud “thunder,” lightning, and noontime darkness due to ashfall. AVO staff immediately confirmed the report by observing a strong eruption signal recorded on the Okmok seismic network and the presence of a large dark ash cloud above Okmok in satellite imagery. Within 5 minutes of the call, AVO declared the volcano at aviation code red, signifying that a highly explosive, ash-rich eruption was under way.

  18. Prominent Determinants of Consumer-Based Brand Equity

    Directory of Open Access Journals (Sweden)

    Elisa Battistoni

    2013-08-01

    Full Text Available In this paper we investigate the most prominent drivers of brand equity, from a consumerbased point of view. We present a new approach for measuring brand equity, which can be applied regardless of the brand sector and is based on the Analytic Hierarchy Process. This approach has the main advantage of allowing for comparisons to be made between non‐directly measurable elements and also has the advantage of enabling the ranking of intangible criteria, such as consumers’ feelings or purchase intentions. We focus on the fashion industry, since we believe in the higher value of our approach when applied to brands which offer products with less tangible characteristics. Thanks to a case study – which involved about 250 interviewees – we succeed in finding and prioritizing the elements which can have an impact on the brand value. We also provide a global ranking for three apparel brands: Gap, H&M and Zara. The results from our model are consistent with other popular ratings and can be extremely useful for brand managers.

  19. Quantifying the cepstral peak prominence, a measure of dysphonia.

    Science.gov (United States)

    Heman-Ackah, Yolanda D; Sataloff, Robert T; Laureyns, Griet; Lurie, Deborah; Michael, Deirdre D; Heuer, Reinhardt; Rubin, Adam; Eller, Robert; Chandran, Swapna; Abaza, Mona; Lyons, Karen; Divi, Venu; Lott, Joanna; Johnson, Jennifer; Hillenbrand, James

    2014-11-01

    The purpose of this study is to establish normative values for the smoothed cepstral peak prominence (CPPS) and its sensitivity and specificity as a measure of dysphonia. Prospective cohort study. Voice samples of running speech were obtained from 835 patients and 50 volunteers. Eight laryngologists and four speech-language pathologists performed perceptual ratings of the voice samples on the degree of dysphonia/normality using an analog scale. The mean of their perceptual ratings was used as the gold standard for the detection of the presence or absence of dysphonia. CPPS was measured using the CPPS algorithm of Hillenbrand, and the cut-off value for positivity that has the highest sensitivity and specificity for discriminating between normal and severely dysphonia voices was determined based on ROC-curve analysis. The cut-off value for normal for CPPS was set at 4.0 or higher, which gave a sensitivity of 92.4%, a specificity of 79%, a positive predictive value of 82.5%, and a negative predictive value of 90.8%. The area under the receiver operating characteristic (ROC) curve was 0.937 (P dysphonia, with the normal value of CPPS (Hillenbrand algorithm) of a running speech sample being defined as a value of 4.0 or higher. Copyright © 2014 The Voice Foundation. All rights reserved.

  20. A Case of Diabetic Macular Edema with Prominent Chorioretinal Folds

    Directory of Open Access Journals (Sweden)

    Takaki Sato

    2017-03-01

    Full Text Available Purpose: To report a case of diabetic macular edema with prominent chorioretinal folds. Case Report: This study involved a 55-year-old male with untreated bilateral diabetic retinopathy who had undergone cataract surgery at another clinic. Following that surgery, diabetic macular edema rapidly exacerbated, accentuating marked cystoid macular edema and radial chorioretinal folds in the macula. Investigation of his medical history revealed that in addition to diabetes, he had uncontrolled hypertension and severe diabetic nephropathy. Vitreous surgery was performed on both eyes due to a resistance to a subtenon injection of triamcinolone acetonide or intravitreal injection of an antivascular endothelial growth factor agent. After surgery, the macular edema and chorioretinal folds showed a tendency towards improvement. Thereafter, kidney transplant surgery was performed for renal failure, and a mild tendency of chorioretinal folds was observed. Conclusion: In the case presented in this study, we observed remarkable cystoid macular edema in the fovea centralis and theorize that distortion with the surrounding tissue might have occurred, thus leading to the formation of chorioretinal folds around the macula.

  1. Radiologic comparison of erosive polyarthritis with prominent interphalangeal involvement

    International Nuclear Information System (INIS)

    Gold, R.H.; Bassett, L.W.; Theros, E.G.

    1982-01-01

    Psoriatic arthritis, Reiter's disease, and multicentric reticulohistiocytosis may manifest prominent interphalangeal joint and cutaneous involvement. All three disorders may also affect the sacroiliac joints and spine. Despite these similarities, there are basic radiologic differences enabling distinction between the three disorders. Erosive osteoarthritis must also be considered in the differential diagnosis of interphalangeal erosive arthritis. Psoriatic erosions are characteristically ill defined, often bilaterally asymmetrical, usually unaccompanied by significant osteoporosis, and frequently associated with florid proliferation of subperiosteal new bone. An unilateral polyarticular pattern, which often occurs in a single ray, is the most prevalent of several patterns of involvement. Reiter's disease exhibits many clinical and radiologic similarities to psoriatic arthritis, but in the former there tends to be selective involvement of the joints of the lower limbs and particularly the feet, with relative sparing of the hands and wrists, while in the latter the joints of the upper and lower limbs tend to be involved to an equal extent. Multicentric reticulohistiocytosis (MR). Lesions predominate in skin and synovium and result in sharply circumscribed, rapidly progressive, strikingly bilaterally symmetrical erosions spreading from joint margins to articular surfaces. Most or all of the diarthrodial joints may be affected, but interphalangeal joint predominance and early and severe atlanto-axial involvement are characteristic. Erosive osteoarthritis is characterized by interphalangeal subchondral erosions, accompanying periosteal new bone that is more subtle than that of psoriatic arthritis, and interphalangeal bony ankylosis that occurs with the same frequency as that of psoriatic arthritis. (orig.)

  2. Ionospheric "Volcanology": Ionospheric Detection of Volcano Eruptions

    Science.gov (United States)

    Astafyeva, E.; Shults, K.; Lognonne, P. H.; Rakoto, V.

    2016-12-01

    It is known that volcano eruptions and explosions can generate acoustic and gravity waves. These neutral waves further propagate into the atmosphere and ionosphere, where they are detectable by atmospheric and ionospheric sounding tools. So far, the features of co-volcanic ionospheric perturbations are not well understood yet. The development of the global and regional networks of ground-based GPS/GNSS receivers has opened a new era in the ionospheric detection of natural hazard events, including volcano eruptions. It is now known that eruptions with the volcanic explosivity index (VEI) of more than 2 can be detected in the ionosphere, especially in regions with dense GPS/GNSS-receiver coverage. The co-volcanic ionospheric disturbances are usually characterized as quasi-periodic oscillations. The Calbuco volcano, located in southern Chile, awoke in April 2015 after 43 years of inactivity. The first eruption began at 21:04UT on 22 April 2015, preceded by only an hour-long period of volcano-tectonic activity. This first eruption lasted 90 minutes and generated a sub-Plinian (i.e. medium to large explosive event), gray ash plume that rose 15 km above the main crater. A larger second event on 23 April began at 04:00UT (01:00LT), it lasted six hours, and also generated a sub-Plinian ash plume that rose higher than 15 km. The VEI was estimated to be 4 to 5 for these two events. In this work, we first study ionospheric TEC response to the Calbuco volcano eruptions of April 2015 by using ground-based GNSS-receivers located around the volcano. We analyze the spectral characteristics of the observed TEC variations and we estimate the propagation speed of the co-volcanic ionospheric perturbations. We further proceed with the normal mode summation technique based modeling of the ionospheric TEC variations due to the Calbuco volcano eruptions. Finally, we attempt to localize the position of the volcano from the ionospheric measurements, and we also estimate the time of the

  3. Multiple Eruptive Keratoacanthomas Arising in a Tattoo

    Science.gov (United States)

    Vitiello, Magalys; Echeverria, Begoña; Romanelli, Paolo; Abuchar, Adriana

    2010-01-01

    Keratoacanthomas are rapidly growing, keratinizing, epithelial neoplasms that tend to spontaneously involute and are rarely multiple or eruptive. There is still disagreement on whether or not this condition is a malignancy or a benign epidermal neoplasm; nevertheless, its appearance on tattoos has been reported in rare instances. When waiting for spontaneous involution is not an option, surgery is the preferred treatment. Other therapeutic modalities used for the treatment of this condition include radiotherapy; cryotherapy; laser therapy; and multiple intralesional, topical, and systemic agents. The authors report a patient who developed multiple, eruptive keratoacanthomas in the red ink portions of a tattoo and was successfully treated with acitretin. PMID:20725558

  4. Toward detailed prominence seismology I. Computing accurate 2.5D magnetohydrodynamic equilibria

    NARCIS (Netherlands)

    Blokland, J.W.S.; Keppens, R.

    2011-01-01

    Context. Prominence seismology exploits our knowledge of the linear eigenoscillations for representative magnetohydrodynamic models of filaments. To date, highly idealized models for prominences have been used, especially with respect to the overall magnetic configurations. Aims. We initiate a more

  5. Relationship between gestational age, birth weight and deciduous tooth eruption

    Directory of Open Access Journals (Sweden)

    Afrin Mohamed Khalifa

    2014-06-01

    Conclusion: Delayed tooth eruption was related to lower birth weight and prematurity. The delayed eruption in preterm babies may be related to premature birth and not to a delay in dental development.

  6. Social and environmental impact of volcaniclastic flows related to 472 AD eruption at Vesuvius from stratigraphic and geoarcheological data

    Science.gov (United States)

    Di Vito, Mauro A.; de Vita, Sandro; Rucco, Ilaria; Bini, Monica; Zanchetta, Giovanni; Aurino, Paola; Cesarano, Mario; Ebanista, Carlo; Rosi, Mauro; Ricciardi, Giovanni

    2017-04-01

    There is a growing number of evidences in the surrounding plain of Somma-Vesuvius volcano which indicate that along with primary volcanic processes (i.e. fallout, pyroclastic density currents) the syn-eruptive and post-eruptive volcaniclastic remobilization has severely impacted the ancient civilizations, which flourished in the area. This represents an important starting point for understanding the future hazard related to a potential (and not remote) renewal of volcanic activity of the Campaniana volcanoes. We present geoarcheological and stratigraphic data obtained from the analysis of more than 160 sections in the Campanian plain showing the widespread impact of volcaniclastic debris flows and floods originated from the rapid remobilization of the products of the AD 472 eruption of Somma-Vesuvius, both on the environment and on the human landscape. This eruption was one of the two sub-Plinian historical events of Somma Vesuvius. This event largely impacted the northern and eastern territory surrounding the volcano with deposition of a complex sequence of pyroclastic-fallout and -current deposits. These sequences were variably affected by syn- and post-eruptive mobilization both along the Somma-Vesuvius slopes and the Apennine valleys with the emplacement of thick mud- and debris-flows which strongly modified the preexisting paleogeography of the Plain with irretrievable damages to the agricultural and urban landscape. The multidisciplinary approach to the study of the sequences permitted to reconstruct the palaeoenvironment before the eruption and the timing of the emplacement of both pyroclastic and volcanoclastic deposits. The preexisting landscape was characterized by intense human occupation, although showing strong evidences of degradation and abandonment due to the progressive decline of the Roman Empire. The impact of volcaniclastic flows continued for decades after the eruption as highlighted in the studied sequences by stratigraphic and archaeologic

  7. New Perspectives on the Climatic Impact of the 1600 Eruption of Huaynaputina Volcano, Peru

    Science.gov (United States)

    Verosub, K. L.; Lippman, J.

    2007-05-01

    A critical test of the new understanding of volcanic aerosols developed since 1982 is to determine if it can predict the effects of larger eruptions than those that have occurred since El Chichon. To do that, requires detailed information about the effects of specific large eruptions. We have been investigating the human and climatic impacts of the 1600 eruption of Huaynaputina volcano in Peru. The estimated Volcanic Explosivity Index for this eruption is 6, which is comparable to that of the 1815 eruption of Tambora volcano in Indonesia, which produced global cooling and led to crop failures, famine and social unrest. On the basis of tree-ring data, Briffa et al. (1998) suggested that the most severe short-term Northern Hemisphere cooling event of the past 600 years occurred in 1601, the year following the Huaynaputina eruption. In order gain a better understanding of the nature and extent of this cooling, we have been collecting annual time series that provide information about climatic conditions during time intervals that bracket the Huaynaputina eruption. Among the time series that we have examined (or plan to examine) are ice conditions in the harbors of Tallinn, Estonia, and Riga, Latvia and in Lake Suwa in Japan: cherry blossom blooming (sakura) dates from Kyoto, Japan; records of agricultural production from China and Russia; tithe records from the Spanish colonial empire; dates of the beginning of the wine harvest in France and the rye harvest in Sweden; prices of agricultural commodities in Europe; and river flows from the Nile and the Colorado. Often, in the records we have examined, 1601 shows up as one of the coldest years, if not the coldest year. In addition, the worst famines in Russian history took place between 1601 and 1603, which eventually led to the overthrow of Tsar Boris Gudonov. Thus, there is considerable evidence that the climatic impacts of the Huaynaputina eruption were comparable to those from the Tambora eruption. This result is

  8. Pre-eruptive storage conditions of the Holocene dacite erupted from Kizimen Volcano, Kamchatka

    Science.gov (United States)

    Browne, B.; Izbekov, P.; Eichelberger, J.; Churikova, T.

    2010-01-01

    This study describes an investigation of the pre-eruptive conditions (T, P and fO2) of dacite magma erupted during the KZI cycle (12,000-8400 years ago) of Kizimen Volcano, Kamchatka, the earliest, most voluminous and most explosive eruption cycle in the Kizimen record. Hydrothermal, water-saturated experiments on KZI dacite pumice coupled with titanomagnetite-ilmenite geothermometry calculations require that the KZI dacite existed at a temperature of 823 ?? 20??C and pressures of 125-150 MPa immediately prior to eruption. This estimate corresponds to a lithologic contact between Miocene volcaniclastic rocks and Pliocene-Pleistocene volcanic rocks located at a depth of 5-6 km beneath the Kizimen edifice, which may have facilitated the accumulation of atypically large volumes of gas-rich dacite during the KZI cycle.

  9. Ash aggregation in explosive volcanic eruptions

    Science.gov (United States)

    Telling, J. W.; Dufek, J.

    2010-12-01

    We present the result of a recent experimental and numerical investigation of ash aggregation in volcanic plumes. Eruption dynamics are sensitive to microphysical processes, like ash aggregation, yet are difficult to parameterize based on dynamics simulations of whole eruption columns due to the lack of sufficient resolution. Here we present the results of experiments that develop a probabilistic relationship for ash aggregation based on particle size, collisional energy and atmospheric water vapor. These relationships can be integrated into large-scale simulations of eruption column behavior in conjunction with a reconstructed velocity distribution of the ash in the column. The physical experiment was carried out in a contained tank designed to allow for the control of atmospheric water vapor. Image data is recorded with a high speed camera and post-processed to determine the number of collisions, energy of collisions and probability of aggregation. We will present the results of aggregation probability and the effects of incorporating these results into a multiphase model of a three-dimensional eruption column, where the effects of ash aggregation are especially important in regions of high shear and high granular temperature.

  10. Aggregation of volcanic ash in explosive eruptions

    Science.gov (United States)

    Telling, J. W.; Dufek, J.

    2009-12-01

    We present the result of a recent experimental and numerical investigation of ash aggregation in volcanic plumes. Eruption dynamics are sensitive to microphysical processes, like ash aggregation, yet are difficult to parameterize based on dynamics simulations of whole eruption columns due to the lack of sufficient resolution. Here we present the results of experiments that develop a probabilistic relationship for ash aggregation based on impact velocity and atmospheric conditions (water vapor and atmospheric pressure). The probabilistic relationship can be integrated, in conjunction with a reconstructed velocity distribution of the ash in the column, and then can be readily incorporated in large-scale simulations of eruption column behavior. We also conduct detailed Eulerian-Lagrangian simulations at the scale of our experiment as a test of the ash aggregation relationship. The physical experiment was carried out in a contained tank designed to allow for the control of ‘atmospheric’ conditions. The tank can be depressurized as needed, using the gas inlet and the attached vacuum pump, and the ambient humidity can be altered by adjusting the gas mixture at the inlet. Image data is recorded with a high speed camera and post-processed to determine the number of collisions, energy of collisions and probability of aggregation. We will present the results of aggregation probability and the effects of incorporating these results into a multiphase model of a three-dimensional eruption column, where the effects of ash aggregation are especially important in regions of high shear and high granular temperature.

  11. Emotional Eruptions, Volcanic Activity and Global Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2011-01-01

    The eruption of Iceland’s Eyjafjallajökull volcano in April 2010 set off a number of environmental, economic and cultural effects obstructing thousands of people in the midst of their global mobility flows. It halted, as well, the exchange of goods and commodities and exposed the vulnerability of...

  12. Evolving Coronal Holes and Interplanetary Erupting Stream ...

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... Coronal holes and interplanetary disturbances are important aspects of the physics of the Sun and heliosphere. Interplanetary disturbances are identified as an increase in the density turbulence compared with the ambient solar wind. Erupting stream disturbances are transient large-scale structures of ...

  13. Evolving Coronal Holes and Interplanetary Erupting Stream ...

    Indian Academy of Sciences (India)

    Abstract. Coronal holes and interplanetary disturbances are important aspects of the physics of the Sun and heliosphere. Interplanetary distur- bances are identified as an increase in the density turbulence compared with the ambient solar wind. Erupting stream disturbances are transient large-scale structures of enhanced ...

  14. Evolving Coronal Holes and Interplanetary Erupting Stream ...

    Indian Academy of Sciences (India)

    ted their sources on the synoptic maps using Carrington coordinates as circles of about 90. ◦ wide. The positional .... the areas of coronal holes, which did not exist in the synoptic chart of the preceding rotation 1680, but are seen to ... of erupting stream on solar disc. The event numbers 7, 8 and 9 refer to Table 1 of Hewish &.

  15. Linking the Lusi mud eruption dynamics with regional and global seismic activity: a statistical analysis.

    Science.gov (United States)

    Collignon, Marine; Hammer, Øyvind; Fallahi, Mohammad J.; Lupi, Matteo; Schmid, Daniel W.; Alwi, Husein; Hadi, Soffian; Mazzini, Adriano

    2017-04-01

    The 29th May 2006, gas water and mud breccia started to erupt at several localities along the Watukosek fault system in the Sidoarjo Regency in East Java Indonesia. The most prominent eruption site, named Lusi, is still active and the emitted material now covers a surface of nearly 7 km2, resulting in the displacement of 60.000 people (up to date). Due to its social and economic impacts, as well as its spectacular dimensions, the Lusi eruption still attracts the attention of international media and scientists. In the framework of the Lusi Lab project (ERC grant n° 308126), many efforts were made to develop a quasi-constant monitoring of the site and the regional areas. Several studies attempted to predict the flow rate evolution or ground deformation, resulting in either overestimating or underestimating the longevity of the eruption. Models have failed because Lusi is not a mud volcano but a sedimentary hosted hydrothermal system that became apparent after the M6.3 Yogyakarta earthquake. Another reason is because such models usually assume that the flow will decrease pacing the overpressure reduction during the deflation of the chamber. These models typically consider a closed system with a unique chamber that is not being recharged. Overall the flow rate has decreased over the past ten years, although it has been largely fluctuating with monthly periods of higher mud breccia discharge. Monitoring of the eruption has revealed that numerous anomalous events are temporally linked to punctual events such as earthquakes or volcanic eruptions. Nevertheless, the quantification of these events has never been investigated in details. In this study, we present a compilation of anomalous events observed at the Lusi site during the last 10 years. Using Monte Carlo simulations, we then statistically compare the displacement, recorded at different seismic stations around Lusi, with the regional and global earthquakes catalogue to test the probability that an earthquake

  16. Eruptive Dynamics Inferred from Textural Analysis of Ash Time Series: The 2015 Reawakening of Cotopaxi Volcano

    Science.gov (United States)

    Gaunt, H. E.; Bernard, B.; Hidalgo, S.; Proaño, A.; Wright, H. M. N.; Mothes, P. A.; Criollo, E.

    2016-12-01

    Analysis of the composition and texture of ash ejected during eruptive episodes can provide valuable information about magma storage and ascent conditions. After 73 years of repose, Cotopaxi volcano erupted after approximately four months of precursory activity that included an increase in seismicity, gas emissions, and minor ground deformation. High frequency ash sampling was realized throughout the new eruptive period and near real-time petrological monitoring of ash samples was used to infer eruption dynamics at Cotopaxi volcano. We collected twenty ash samples between August 14 and November 23, 2015 from a seismic monitoring site on the west flank of the volcano. We classified the different components of the ash into four groups: hydrothermal/altered grains, lithic fragments, potentially juvenile material, and free crystals. The relative proportions of theses grains evolved as the eruption progressed, with increasing amounts of potentially juvenile material and a decrease in hydrothermally altered material through time. Potentially juvenile grains from the initial explosion are microlite-poor and contain hydrothermal minerals (opal and alunite) in contact with fresh glass. The interaction of juvenile magma with the hydrothermal system may have provided the energy to trigger phreatomagmatic explosions at Cotopaxi. However, only the initial explosions preserve textural evidence for this process. Completely aphyric, glassy fragments are absent; likewise, the absence of highly vesiculated pumice or scoria indicates that fragmentation was not the result of bubble wall breakage due to rapid exsolution and expansion of gas in the melt. Furthermore, the crystallinity of juvenile particles increased through time, indicating slowing integrated ascent rates. Nevertheless, continued high SO2 emission rates indicate that the system was open to gas loss, which inhibited the pressurization of the conduit through gas accumulation, reducing the short term possibility of a large

  17. Observations of eruption clouds from Sakura-zima volcano, Kyushu, Japan, from Skylab 4

    Energy Technology Data Exchange (ETDEWEB)

    Friedman, J.D.; Heiken, G.; Randerson, D.; McKay, D.S.

    1976-01-01

    Hasselblad and Nikon stereographic photographs taken from Skylab between 9 June 1973 and 1 February 1974 give synoptic plan views of several entire eruption clouds emanating from Sakura-zima volcano in Kagoshima Bay, Kyushu, Japan. Analytical plots of these stereographic pairs, studied in combination with meteorological data, indicate that the eruption clouds did not penetrate the tropopause and thus did not create a stratospheric dust veil of long residence time. A horizontal eddy diffusivity of the order of 10/sup 6/ cm/sup 2/ s/sup -1/ and a vertical eddy diffusivity of the order of 10/sup 5/ cm/sup 2/ s/sup -1/ were calculated from the observed plume dimensions and from available meteorological data. These observations are the first, direct evidence that explosive eruption at an estimated energy level of about 10/sup 18/ ergs per paroxysm may be too small under atmospheric conditions similar to those prevailing over Sakura-zima for volcanic effluents to penetrate low-level tropospheric temperature inversions and, consequently, the tropopause over northern middle latitudes. Maximum elevation of the volcanic clouds was determined to be 3.4 km. The cumulative thermal energy release in the rise of volcanic plumes for 385 observed explosive eruptions was estimated to be 10/sup 20/ to 10/sup 21/ ergs (10/sup 13/ to 10/sup 14/ J), but the entire thermal energy release associated with pyroclastic activity may be of the order of 2.5 x 10/sup 22/ ergs (2.5 x 10/sup 15/ J). Estimation of the kinetic energy component of explosive eruptions via satellite observation and meteorological consideration of eruption clouds is thus useful in volcanology as an alternative technique to confirm the kinetic energy estimates made by ground-based geological and geophysical methods, and to aid in construction of physical models of potential and historical tephra-fallout sectors with implications for volcano-hazard prediction.

  18. Morphology and Dynamics of Solar Prominences from 3D MHD Simulations

    Science.gov (United States)

    Terradas, J.; Soler, R.; Luna, M.; Oliver, R.; Ballester, J. L.

    2015-01-01

    In this paper we present a numerical study of the time evolution of solar prominences embedded in sheared magnetic arcades. The prominence is represented by a density enhancement in a background-stratified atmosphere and is connected to the photosphere through the magnetic field. By solving the ideal magnetohydrodynamic equations in three dimensions, we study the dynamics for a range of parameters representative of real prominences. Depending on the parameters considered, we find prominences that are suspended above the photosphere, i.e., detached prominences, but also configurations resembling curtain or hedgerow prominences whose material continuously connects to the photosphere. The plasma-β is an important parameter that determines the shape of the structure. In many cases magnetic Rayleigh-Taylor instabilities and oscillatory phenomena develop. Fingers and plumes are generated, affecting the whole prominence body and producing vertical structures in an essentially horizontal magnetic field. However, magnetic shear is able to reduce or even to suppress this instability.

  19. MORPHOLOGY AND DYNAMICS OF SOLAR PROMINENCES FROM 3D MHD SIMULATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Terradas, J.; Soler, R.; Oliver, R.; Ballester, J. L. [Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Luna, M., E-mail: jaume.terradas@uib.es [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain)

    2015-01-20

    In this paper we present a numerical study of the time evolution of solar prominences embedded in sheared magnetic arcades. The prominence is represented by a density enhancement in a background-stratified atmosphere and is connected to the photosphere through the magnetic field. By solving the ideal magnetohydrodynamic equations in three dimensions, we study the dynamics for a range of parameters representative of real prominences. Depending on the parameters considered, we find prominences that are suspended above the photosphere, i.e., detached prominences, but also configurations resembling curtain or hedgerow prominences whose material continuously connects to the photosphere. The plasma-β is an important parameter that determines the shape of the structure. In many cases magnetic Rayleigh-Taylor instabilities and oscillatory phenomena develop. Fingers and plumes are generated, affecting the whole prominence body and producing vertical structures in an essentially horizontal magnetic field. However, magnetic shear is able to reduce or even to suppress this instability.

  20. MORPHOLOGY AND DYNAMICS OF SOLAR PROMINENCES FROM 3D MHD SIMULATIONS

    International Nuclear Information System (INIS)

    Terradas, J.; Soler, R.; Oliver, R.; Ballester, J. L.; Luna, M.

    2015-01-01

    In this paper we present a numerical study of the time evolution of solar prominences embedded in sheared magnetic arcades. The prominence is represented by a density enhancement in a background-stratified atmosphere and is connected to the photosphere through the magnetic field. By solving the ideal magnetohydrodynamic equations in three dimensions, we study the dynamics for a range of parameters representative of real prominences. Depending on the parameters considered, we find prominences that are suspended above the photosphere, i.e., detached prominences, but also configurations resembling curtain or hedgerow prominences whose material continuously connects to the photosphere. The plasma-β is an important parameter that determines the shape of the structure. In many cases magnetic Rayleigh-Taylor instabilities and oscillatory phenomena develop. Fingers and plumes are generated, affecting the whole prominence body and producing vertical structures in an essentially horizontal magnetic field. However, magnetic shear is able to reduce or even to suppress this instability

  1. Thermodynamics of gas and steam-blast eruptions

    Science.gov (United States)

    Mastin, L.G.

    1995-01-01

    Eruptions of gas or steam and non-juvenile debris are common in volcanic and hydrothermal areas. From reports of non-juvenile eruptions or eruptive sequences world-wide, at least three types (or end-members) can be identified: (1) those involving rock and liquid water initially at boiling-point temperatures ('boiling-point eruptions'); (2) those powered by gas (primarily water vapor) at initial temperatures approaching magmatic ('gas eruptions'); and (3) those caused by rapid mixing of hot rock and ground- or surface water ('mixing eruptions'). For these eruption types, the mechanical energy released, final temperatures, liquid water contents and maximum theoretical velocities are compared by assuming that the erupting mixtures of rock and fluid thermally equilibrate, then decompress isentropically from initial, near-surface pressure (???10 MPa) to atmospheric pressure. Maximum mechanical energy release is by far greatest for gas eruptions (??????1.3 MJ/kg of fluid-rock mixture)-about one-half that of an equivalent mass of gunpowder and one-fourth that of TNT. It is somewhat less for mixing eruptions (??????0.4 MJ/kg), and least for boiling-point eruptions (??????0.25 MJ/kg). The final water contents of crupted boiling-point mixtures are usually high, producing wet, sloppy deposits. Final erupted mixtures from gas eruptions are nearly always dry, whereas those from mixing eruptions vary from wet to dry. If all the enthalpy released in the eruptions were converted to kinetic energy, the final velocity (vmax) of these mixtures could range up to 670 m/s for boiling-point eruptions and 1820 m/s for gas eruptions (highest for high initial pressure and mass fractions of rock (mr) near zero). For mixing eruptions, vmax ranges up to 1150 m/s. All observed eruption velocities are less than 400 m/s, largely because (1) most solid material is expelled when mr is high, hence vmax is low; (2) observations are made of large blocks the velocities of which may be less than the

  2. Opal-A in glassy pumice, acid alteration, and the 1817 phreatomagmatic eruption at Kawah Ijen (Java), Indonesia

    Science.gov (United States)

    Lowenstern, Jacob B.; van Hinsberg, Vincent; Berlo, Kim; Liesegang, Moritz; Iacovino, Kayla D.; Bindeman, Ilya N.; Wright, Heather M.

    2018-01-01

    At Kawah Ijen (Indonesia), vigorous SO2 and HCl degassing sustains a hyperacid lake (pH ~0) and intensely alters the subsurface, producing widespread residual silica and advanced argillic alteration products. In 1817, a VEI 2 phreatomagmatic eruption evacuated the lake, depositing a widespread layer of muddy ash fall, and sending lahars down river drainages. We discovered multiple types of opaline silica in juvenile low-silica dacite pumice and in particles within co-erupted laharic sediments. Most spectacular are opal-replaced phenocrysts of plagioclase and pyroxene adjacent to pristine matrix glass and melt inclusions. Opal-bearing pumice has been found at numerous sites, including where post-eruption infiltration of acid water is unlikely. Through detailed analyses of an initial sampling of 1817 eruption products, we find evidence for multiple origins of opaline materials in pumice and laharic sediments. Evidently, magma encountered acid-altered materials in the subsurface and triggered phreatomagmatic eruptions. Syn-eruptive incorporation of opal-alunite clasts, layered opal, and fragment-filled vesicles of opal and glass, all suggest magma-rock interactions in concert with vesiculation, followed by cooling within minutes. Our experiments at magmatic temperature confirm that the opaline materials would show noticeable degradation in time periods longer than a few tens of minutes. Some glassy laharic sedimentary grains are more andesitic than the main pumice type and may represent older volcanic materials that were altered beneath the lake bottom and were forcefully ejected during the 1817 eruption. A post-eruptive origin remains likely for most of the opal-replaced phenocrysts in pumice. Experiments at 25°C and 100°C reveal that when fresh pumice is bathed in Kawah Ijen hyperacid fluid for 6 weeks, plagioclase is replaced without altering either matrix glass or melt inclusions. Moreover, lack of evidence for high-temperature annealing of the opal suggests

  3. Opal-A in Glassy Pumice, Acid Alteration, and the 1817 Phreatomagmatic Eruption at Kawah Ijen (Java, Indonesia

    Directory of Open Access Journals (Sweden)

    Jacob B. Lowenstern

    2018-02-01

    Full Text Available At Kawah Ijen (Indonesia, vigorous SO2 and HCl degassing sustains a hyperacid lake (pH ~0 and intensely alters the subsurface, producing widespread residual silica and advanced argillic alteration products. In 1817, a VEI 2 phreatomagmatic eruption evacuated the lake, depositing a widespread layer of muddy ash fall, and sending lahars down river drainages. We discovered multiple types of opaline silica in juvenile low-silica dacite pumice and in particles within co-erupted laharic sediments. Most spectacular are opal-replaced phenocrysts of plagioclase and pyroxene adjacent to pristine matrix glass and melt inclusions. Opal-bearing pumice has been found at numerous sites, including where post-eruption infiltration of acid water is unlikely. Through detailed analyses of an initial sampling of 1817 eruption products, we find evidence for multiple origins of opaline materials in pumice and laharic sediments. Evidently, magma encountered acid-altered materials in the subsurface and triggered phreatomagmatic eruptions. Syn-eruptive incorporation of opal-alunite clasts, layered opal, and fragment-filled vesicles of opal and glass, all suggest magma-rock interactions in concert with vesiculation, followed by cooling within minutes. Our experiments at magmatic temperature confirm that the opaline materials would show noticeable degradation in time periods longer than a few tens of minutes. Some glassy laharic sedimentary grains are more andesitic than the main pumice type and may represent older volcanic materials that were altered beneath the lake bottom and were forcefully ejected during the 1817 eruption. A post-eruptive origin remains likely for most of the opal-replaced phenocrysts in pumice. Experiments at 25°C and 100°C reveal that when fresh pumice is bathed in Kawah Ijen hyperacid fluid for 6 weeks, plagioclase is replaced without altering either matrix glass or melt inclusions. Moreover, lack of evidence for high-temperature annealing of the

  4. Atmospheric processes affecting the separation of volcanic ash and SO2 in volcanic eruptions: inferences from the May 2011 Grímsvötn eruption

    Directory of Open Access Journals (Sweden)

    F. Prata

    2017-09-01

    Full Text Available The separation of volcanic ash and sulfur dioxide (SO2 gas is sometimes observed during volcanic eruptions. The exact conditions under which separation occurs are not fully understood but the phenomenon is of importance because of the effects volcanic emissions have on aviation, on the environment, and on the earth's radiation balance. The eruption of Grímsvötn, a subglacial volcano under the Vatnajökull glacier in Iceland during 21–28 May 2011 produced one of the most spectacular examples of ash and SO2 separation, which led to errors in the forecasting of ash in the atmosphere over northern Europe. Satellite data from several sources coupled with meteorological wind data and photographic evidence suggest that the eruption column was unable to sustain itself, resulting in a large deposition of ash, which left a low-level ash-rich atmospheric plume moving southwards and then eastwards towards the southern Scandinavian coast and a high-level predominantly SO2 plume travelling northwards and then spreading eastwards and westwards. Here we provide observational and modelling perspectives on the separation of ash and SO2 and present quantitative estimates of the masses of ash and SO2 that erupted, the directions of transport, and the likely impacts. We hypothesise that a partial column collapse or sloughing fed with ash from pyroclastic density currents (PDCs occurred during the early stage of the eruption, leading to an ash-laden gravity intrusion that was swept southwards, separated from the main column. Our model suggests that water-mediated aggregation caused enhanced ash removal because of the plentiful supply of source water from melted glacial ice and from entrained atmospheric water. The analysis also suggests that ash and SO2 should be treated with separate source terms, leading to improvements in forecasting the movement of both types of emissions.

  5. Atmospheric processes affecting the separation of volcanic ash and SO2 in volcanic eruptions: inferences from the May 2011 Grímsvötn eruption

    Science.gov (United States)

    Prata, Fred; Woodhouse, Mark; Huppert, Herbert E.; Prata, Andrew; Thordarson, Thor; Carn, Simon

    2017-09-01

    The separation of volcanic ash and sulfur dioxide (SO2) gas is sometimes observed during volcanic eruptions. The exact conditions under which separation occurs are not fully understood but the phenomenon is of importance because of the effects volcanic emissions have on aviation, on the environment, and on the earth's radiation balance. The eruption of Grímsvötn, a subglacial volcano under the Vatnajökull glacier in Iceland during 21-28 May 2011 produced one of the most spectacular examples of ash and SO2 separation, which led to errors in the forecasting of ash in the atmosphere over northern Europe. Satellite data from several sources coupled with meteorological wind data and photographic evidence suggest that the eruption column was unable to sustain itself, resulting in a large deposition of ash, which left a low-level ash-rich atmospheric plume moving southwards and then eastwards towards the southern Scandinavian coast and a high-level predominantly SO2 plume travelling northwards and then spreading eastwards and westwards. Here we provide observational and modelling perspectives on the separation of ash and SO2 and present quantitative estimates of the masses of ash and SO2 that erupted, the directions of transport, and the likely impacts. We hypothesise that a partial column collapse or sloughing fed with ash from pyroclastic density currents (PDCs) occurred during the early stage of the eruption, leading to an ash-laden gravity intrusion that was swept southwards, separated from the main column. Our model suggests that water-mediated aggregation caused enhanced ash removal because of the plentiful supply of source water from melted glacial ice and from entrained atmospheric water. The analysis also suggests that ash and SO2 should be treated with separate source terms, leading to improvements in forecasting the movement of both types of emissions.

  6. The palaeogeographic setting and the local environmental impact of the 130 ka Falconiera tuff-cone eruption (Ustica island, Italy)

    Science.gov (United States)

    de Vita, Sandro; Foresta Martin, Franco

    2017-04-01

    This research focuses on the effects of the last eruption at Ustica (Suthern Tyrrhenian Sea, Italy), which formed the Falconiera tuff-cone at around 130 ka BP in the north-eastern tip of the island. This eruption was mainly explosive and phreatomagmatic, and emplaced a series of pyroclastic surge beds that formed an asymmetric tuff cone. This is the most easily recognizable volcanic edifice on Ustica, although its north-eastern sector has been partially eroded. A section of the feeding conduit is exposed northward, and is composed of lavas that fed the last stages of the eruption characterized by an intracrateric lava lake and a Strombolian scoria-fallout deposit. The eruption occurred during Upper Pleistocene Marine Isotopic Substage 5.5, a warm period characterized by a high sea-level stand (6±3 m above the present sea level in stable areas) and the diffusion of subtropical flora and fauna across the Mediterranean sea. This eruption slightly modified the morphology of Ustica, but impacted both marine and terrestrial environments, burying beach deposits rich in mollusk shells (i.e. Strombus bubonius, Conus testudinarius, Brachidontes puniceus), colonies of corals (Cladocora caespitosa) and subaerial plants (Chamaerops humilis). These organisms, found in some cases in their life position, along with other lines of evidence, provide information on the palaeogeography of this sector of the island at the time of the eruption, and on the local impact of this event on the environment.

  7. The terminal Paleozoic fungal event: evidence of terrestrial ecosystem destabilization and collapse.

    Science.gov (United States)

    Visscher, H; Brinkhuis, H; Dilcher, D L; Elsik, W C; Eshet, Y; Looy, C V; Rampino, M R; Traverse, A

    1996-03-05

    Because of its prominent role in global biomass storage, land vegetation is the most obvious biota to be investigated for records of dramatic ecologic crisis in Earth history. There is accumulating evidence that, throughout the world, sedimentary organic matter preserved in latest Permian deposits is characterized by unparalleled abundances of fungal remains, irrespective of depositional environment (marine, lacustrine, fluviatile), floral provinciality, and climatic zonation. This fungal event can be considered to reflect excessive dieback of arboreous vegetation, effecting destabilization and subsequent collapse of terrestrial ecosystems with concomitant loss of standing biomass. Such a scenario is in harmony with predictions that the Permian-Triassic ecologic crisis was triggered by the effects of severe changes in atmospheric chemistry arising from the rapid eruption of the Siberian Traps flood basalts.

  8. Eruptive history of the youngest Mexican Shield and Mexico's most voluminous Holocene eruption: Cerro El Metate

    Science.gov (United States)

    Oryaëlle Chevrel, Magdalena; Guilbaud, Marie-Noelle; Siebe, Claus

    2016-04-01

    Small to medium-sized shield volcanoes are an important component of many volcanic fields on Earth. The Trans-Mexican Volcanic Belt, one of the most complex and active continental arcs worldwide, displays a large number of such medium-sized volcanoes. In particular the Michoacán-Guanajuato Volcanic Field (MGVF) situated in central Mexico, is the largest monogenetic volcanic field in the world and includes more than 1000 scoria cones and about four hundred medium-sized volcanoes, also known as Mexican shields. The Mexican shields nevertheless represent nearly 70% of the total volume erupted since 1 Ma and hence played a considerable role in the formation of the MGVF. However, the source, storage, and transport as well as the physical properties (density, viscosity, volatile content, etc.) of the magmas involved in these eruptions remain poorly constrained. Here, we focus on Cerro El Metate, the youngest monogenetic andesite shield volcano of the field. New C14 dates for the eruption yield a young age (~AD 1250), which briefly precedes the initial rise of the Tarascan Empire (AD 1350-1521) in this region. This volcano has a minimum volume of ~9.2 km3 DRE, and its viscous lava flows were emplaced during a single eruption over a period of ~35 years covering an area of 103 km2. By volume, this is certainly the largest eruption during the Holocene in Mexico, and it is the largest andesitic effusive eruption known worldwide for this period. Such a large volume of lava erupted in a relatively short time had a significant impact on the environment (modification of the hydrological network, forest fires, etc.), and hence, nearby human populations probably had to migrate. Its eruptive history was reconstructed through detailed mapping, and geochemical and rheological analyses of its thick hornblende-bearing andesitic flows. Early and late flows have distinct morphologies, chemical and mineralogical compositions, and isotopic signatures which show that these lavas were fed by

  9. Contrasting styles of deep-marine pyroclastic eruptions revealed from Axial Seamount push core records

    Science.gov (United States)

    Portner, Ryan A.; Clague, David A.; Helo, Christoph; Dreyer, Brian M.; Paduan, Jennifer B.

    2015-08-01

    bioturbation or other interbedded lithofacies, and presence of normal grading suggests prolonged eruption activity and deposition via turbidity flows or suspension fallout. The proximity of ancient hydrothermal muddy tuff lithofacies and active hydrothermal vents to caldera walls suggest that phreatomagmatic activity was linked to shallow circulation of fluids along caldera ring-faults rooted to underlying magma conduits and shallow reservoirs. This study provides evidence for two distinctly different pyroclastic eruption styles and provides a framework to further develop existing models of deep-sea explosive volcanism.

  10. Hydrothermal eruptions of Nisyros (Dodecanese, Greece). Past events and present hazard

    Science.gov (United States)

    Marini, L.; Principe, C.; Chiodini, G.; Cioni, R.; Fytikas, M.; Marinelli, G.

    1993-05-01

    The detailed analysis of the craters of hydrothermal eruptions and related products present on Nisyros Island demonstrates the ephemerality of these morphological forms. In other words, the mere recognizable existence of the craters and associated deposits implies recency of hydrothermal activity. The minimum temperature required to cause the explosive phenomenon and, possibly, the depth of the reservoir (which can be evaluated on the basis of the correlation between the diameter of the crater and the depth of explosion as proposed by Fytikas and Marinelli, 1976) are therefore closely representative of the current hydrothermal circulation. Both field evidence and historical records indicate that all the deposits of hydrothermal eruption recognized on Nisyros Island were emplaced as debris flows. Almost all the ballistic ejecta were entrained in these debris flows and either redeposited far from their landing sites or involved in later crater collapse and erosion. This emplacing mechanism implies that the original products were characterized by a water content higher than about 5% by weight. Steam-driven hydrothermal eruptions, one of which took place in 1871, originated deposits of limited dispersion, as no sign of these erodible products can be found in the field today. Surface geology and fluid geochemistry, together with subsurface information (e.g., primary and hydrothermal lithologies, distribution of temperature with depth, physical-chemical characteristics of deep water-bearing zones) indicate that two distinct hydrothermal aquifers are present underneath the southeastern part of the caldera floor. Both aquifers were probably involved in the most important historically documented hydrothermal eruptions, which occurred in 1873. At that time, violent earthquakes fractured the brittle aquiclude separating the two aquifers and caused a sudden transfer of fluids from the deep to the shallow aquifer, thus triggering the hydrothermal eruptions. Hydrothermal

  11. Timing of Magma Mixing Prior to the 2011 Eruption of Shinmoedake, Japan: On the Relationship Between Magma Injection, Magma Mixing, and Eruption Triggering

    Science.gov (United States)

    Tomiya, A.; Miyagi, I.; Saito, G.; Geshi, N.

    2013-12-01

    Various petrological evidences indicate magma mixing often preceded volcanic eruptions. Magma injection into the associated magma chambers also often occurs prior to eruptions as evidenced by inflation of a volcanic edifice. However, the relationship between magma injection, magma mixing, and eruption triggering is unclear because injection does not necessarily cause instantaneous mixing if the injected magma is sufficiently denser than the pre-existing magma and has formed stable stratified layers. To investigate the relationship, we estimated the timing of magma mixing prior to the 2011 sub-Plinian eruptions of Shinmoedake volcano, Kirishima volcanic group, Japan, on the basis of chemical zoning observed in magnetite phenocrysts and numerical diffusion modeling. We compared the timing with that of volcanic inflation/deflation processes. The eruptive products are comprised mainly of phenocryst-rich (28 vol%) gray pumice (SiO2 = 57 wt%) with minor amount of white pumice (SiO2 = 62 wt%). We recognized two magmatic end members, low-T dacitic magma and high-T mafic magma (basalt or basaltic andesite), and hybrid andesitic magma on the basis of our petrologic studies. Gray pumice is comprised mainly of the hybrid andesitic magma. White pumice is comprised mainly of the low-T dacitic magma with mixing of small volume of the hybrid andesitic magma. Most of the magnetite phenocrysts (type-A1) were crystallized in the hybrid andesitic magma. Their zoning profiles showed considerable increase in Mg and Al contents toward the rims of the phenocrysts, due to mixing with the high-T mafic magma. We calculated the time for diffusion to form these zoning profiles to be only 0.4 to 3 days. The short time scale suggests that the mixing of high-T magma triggered the sub-Plinian eruptions. This mixing process was not accompanied by a significant change in the volume of the magma chamber because no significant crustal deformation was observed several days prior to the eruptions (Japan

  12. Vesiculation of basaltic magma during eruption

    Science.gov (United States)

    Mangan, Margaret T.; Cashman, Katharine V.; Newman, Sally

    1993-01-01

    Vesicle size distributions in vent lavas from the Pu'u'O'o-Kupaianaha eruption of Kilauea volcano are used to estimate nucleation and growth rates of H2O-rich gas bubbles in basaltic magma nearing the earth's surface (≤120 m depth). By using well-constrained estimates for the depth of volatile exsolution and magma ascent rate, nucleation rates of 35.9 events ⋅ cm-3 ⋅ s-1 and growth rates of 3.2 x 10-4cm/s are determined directly from size-distribution data. The results are consistent with diffusion-controlled growth as predicted by a parabolic growth law. This empirical approach is not subject to the limitations inherent in classical nucleation and growth theory and provides the first direct measurement of vesiculation kinetics in natural settings. In addition, perturbations in the measured size distributions are used to examine bubble escape, accumulation, and coalescence prior to the eruption of magma.

  13. An Erupted Dilated Odontoma: A Rare Presentation

    Directory of Open Access Journals (Sweden)

    Gaurav Sharma

    2016-01-01

    Full Text Available A dilated odontoma is an extremely rare developmental anomaly represented as a dilatation of the crown and root as a consequence of a deep, enamel-lined invagination and is considered a severe variant of dens invaginatus. An oval shape of the tooth lacking morphological characteristics of a crown or root implies that the invagination happened in the initial stages of morphodifferentiation. Spontaneous eruption of an odontoma is a rare occurrence and the occurrence of a dilated odontoma in a supernumerary tooth is even rarer with only a few case reports documented in the English literature. We present an extremely rare case of erupted dilated odontoma occurring in the supernumerary tooth in anterior maxillary region in an 18-year-old male, which, to the best of our knowledge, is the first ever case reported in English literature.

  14. An Erupted Dilated Odontoma: A Rare Presentation

    Science.gov (United States)

    Sharma, Gaurav; Nagra, Amritpreet; Singh, Gurkeerat; Nagpal, Archna; Soin, Atul; Bhardwaj, Vishal

    2016-01-01

    A dilated odontoma is an extremely rare developmental anomaly represented as a dilatation of the crown and root as a consequence of a deep, enamel-lined invagination and is considered a severe variant of dens invaginatus. An oval shape of the tooth lacking morphological characteristics of a crown or root implies that the invagination happened in the initial stages of morphodifferentiation. Spontaneous eruption of an odontoma is a rare occurrence and the occurrence of a dilated odontoma in a supernumerary tooth is even rarer with only a few case reports documented in the English literature. We present an extremely rare case of erupted dilated odontoma occurring in the supernumerary tooth in anterior maxillary region in an 18-year-old male, which, to the best of our knowledge, is the first ever case reported in English literature. PMID:26989523

  15. Orthodontic treatment for prominent lower front teeth (Class III malocclusion) in children.

    Science.gov (United States)

    Watkinson, Simon; Harrison, Jayne E; Furness, Susan; Worthington, Helen V

    2013-09-30

    Prominent lower front teeth (termed reverse bite; under bite; Class III malocclusion) may be due to a combination of the jaw or tooth positions or both. The upper jaw (maxilla) can be too far back or the lower jaw (mandible) too far forward, or both. Prominent lower front teeth can also occur if the upper front teeth (incisors) are tipped back or the lower front teeth are tipped forwards, or both. Various treatment approaches have been described to correct prominent lower front teeth in children and adolescents. To assess the effects of orthodontic treatment for prominent lower front teeth in children and adolescents. We searched the following databases: Cochrane Oral Health Group's Trials Register (to 7 January 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 12), MEDLINE via OVID (1946 to 7 January 2013), and EMBASE via OVID (1980 to 7 January 2013). Randomised controlled trials (RCTs) recruiting children or adolescents or both (aged 16 years or less) receiving any type of orthodontic treatment to correct prominent lower front teeth (Class III malocclusion). Orthodontic treatments were compared with control groups who received either no treatment, delayed treatment or a different active intervention. Screening of references, identification of included and excluded studies, data extraction and assessment of the risk of bias of the included studies was performed independently and in duplicate by two review authors. The mean differences with 95% confidence intervals were calculated for continuous data. Meta-analysis was only undertaken when studies of similar comparisons reported comparable outcome measures. A fixed-effect model was used. The I2 statistic was used as a measure of statistical heterogeneity. Seven RCTs with a total of 339 participants were included in this review. One study was assessed as at low risk of bias, three studies were at high risk of bias, and in the remaining three studies risk of bias

  16. Effect of early childhood malnutrition on tooth eruption in Haitian adolescents.

    Science.gov (United States)

    Psoter, W; Gebrian, B; Prophete, S; Reid, B; Katz, R

    2008-04-01

    The objective of this retrospective cohort study was to determine the effects of early childhood protein-energy malnutrition (EC-PEM) and current nutritional status as defined by anthropomorphic measures on the exfoliation and eruption patterns of teeth among adolescents. Oral clinical examinations were conducted in 2005 using World Health Organization (WHO) diagnostic criteria on 498 11- to 13-year-old Haitians for whom early childhood malnutrition data were available. Anthropomorphic records (weight-for-age) from the Haitian Health Foundation computerized database on children from birth through 5-years old were utilized. Current heights and weights were ascertained. Both sets of data were converted to z-scores based on the National Center for Health Statistics (NCHS) referent database. Based upon these z-scores, EC-PEM and current malnutrition categories were developed for this study. The analyses separately regressed the number of primary and permanent teeth on age, gender, EC-PEM status and current nutritional status. Both a delayed exfoliation of primary teeth and a delayed eruption of permanent teeth were associated with EC-PEM and current stunting in adolescence. The observed associations were either direct and statistically significant or indirectly demonstrated by presenting evidence of confounding. The overall interpretation of the models is that malnutrition beginning in the earliest years and extending throughout childhood influences the exfoliation and eruption of teeth. These findings present evidence of an association between tooth exfoliation/eruption patterns and both EC-PEM and nutritional insufficiency (stunting) throughout childhood. This observed delay in the exfoliation of the primary dentition and in the eruption of the permanent dentition has practical significance in interpreting age-specific dental caries data from populations with different malnutrition experiences.

  17. When does eruption run-up begin? Multidisciplinary insight from the 1999 eruption of Shishaldin volcano

    Science.gov (United States)

    Rasmussen, Daniel J.; Plank, Terry A.; Roman, Diana C.; Power, John A.; Bodnar, Robert J.; Hauri, Erik H.

    2018-03-01

    During the run-up to eruption, volcanoes often show geophysically detectable signs of unrest. However, there are long-standing challenges in interpreting the signals and evaluating the likelihood of eruption, especially during the early stages of volcanic unrest. Considerable insight can be gained from combined geochemical and geophysical studies. Here we take such an approach to better understand the beginning of eruption run-up, viewed through the lens of the 1999 sub-Plinian basaltic eruption of Shishaldin volcano, Alaska. The eruption is of interest due to its lack of observed deformation and its apparent long run-up time (9 months), following a deep long-period earthquake swarm. We evaluate the nature and timing of recharge by examining the composition of 138 olivine macrocrysts and 53 olivine-hosted melt inclusions and through shear-wave splitting analysis of regional earthquakes. Magma mixing is recorded in three crystal populations: a dominant population of evolved olivines (Fo60-69) that are mostly reversely zoned, an intermediate population (Fo69-76) with mixed zonation, and a small population of normally zoned more primitive olivines (Fo76-80). Mixing-to-eruption timescales are obtained through modeling of Fe-Mg interdiffusion in 78 olivines. The large number of resultant timescales provides a thorough record of mixing, demonstrating at least three mixing events: a minor event ∼11 months prior to eruption, overlapping within uncertainty with the onset of deep long-period seismicity; a major event ∼50 days before eruption, coincident with a large (M5.2) shallow earthquake; and a final event about a week prior to eruption. Shear-wave splitting analysis shows a change in the orientation of the local stress field about a month after the deep long-period swarm and around the time of the M5.2 event. Earthquake depths and vapor saturation pressures of Raman-reconstructed melt inclusions indicate that the recharge magma originated from depths of at least 20

  18. A Statistical Study of Solar Filament Eruptions

    Science.gov (United States)

    Schanche, Nicole; Aggarwal, Ashna; Reeves, Kathy; Kempton, Dustin James; Angryk, Rafal

    2016-05-01

    Solar filaments are cool, dark channels of partially-ionized plasma that lie above the chromosphere. Their structure follows the neutral line between local regions of opposite magnetic polarity. Previous research (e.g. Schmieder et al. 2013, McCauley et al. 2015) has shown a positive correlation (70-80%) between the occurrence of filament eruptions and coronal mass ejections (CME’s). In this study, we attempt to use properties of the filament in order to predict whether or not a given filament will erupt. This prediction would help to better predict the occurrence of an oncoming CME. To track the evolution of a filament over time, a spatio-temporal algorithm that groups separate filament instances from the Heliophysics Event Knowledgebase (HEK) into filament tracks was developed. Filament features from the HEK metadata, such as length, chirality, and tilt are then combined with other physical features, such as the overlying decay index for two sets of filaments tracks - those that erupt and those that remain bound. Using statistical methods such as the Kolmogrov-Smirnov test and a Random Forest Classifier, we determine the effectiveness of the combined features in prediction. We conclude that there is significant overlap between the properties of filaments that erupt and those that do not, leading to predictions only ~5-10% above chance. However, the changes in features, such as a change in the filament's length over time, were determined to have the highest predictive power. We discuss the possible physical connections with the change in these features."This project has been supported by funding from the Division of Advanced Cyberinfrastructure within the Directorate for Computer and Information Science and Engineering, the Division of Astronomical Sciences within the Directorate for Mathematical and Physical Sciences, and the Division of Atmospheric and Geospace Sciences within the Directorate for Geosciences, under NSF award #1443061.”

  19. Volcanic Lightning in Eruptions of Sakurajima Volcano

    Science.gov (United States)

    Edens, Harald; Thomas, Ronald; Behnke, Sonja; McNutt, Stephen; Smith, Cassandra; Farrell, Alexandra; Van Eaton, Alexa; Cimarelli, Corrado; Cigala, Valeria; Eack, Ken; Aulich, Graydon; Michel, Christopher; Miki, Daisuke; Iguchi, Masato

    2016-04-01

    In May 2015 a field program was undertaken to study volcanic lightning at the Sakurajima volcano in southern Japan. One of the main goals of the study was to gain a better understanding of small electrical discharges in volcanic eruptions, expanding on our earlier studies of volcanic lightning at Augustine and Redoubt volcanoes in Alaska, USA, and Eyjafjallajökull in Iceland. In typical volcanic eruptions, electrical activity occurs at the onset of an eruption as a near-continual production of VHF emissions at or near to the volcanic vent. These emissions can occur at rates of up to tens of thousands of emissions per second, and are referred to as continuous RF. As the ash cloud expands, small-scale lightning flashes of several hundred meters length begin to occur while the continuous RF ceases. Later on during the eruption larger-scale lightning flashes may occur within the ash cloud that are reminiscent of regular atmospheric lightning. Whereas volcanic lightning flashes are readily observed and reasonably well understood, the nature and morphology of the events producing continuous RF are unknown. During the 2015 field program we deployed a comprehensive set of instrumentation, including a 10-station 3-D Lightning Mapping Array (LMA) that operated in 10 μs high time resolution mode, slow and fast ΔE antennas, a VHF flat-plate antenna operating in the 20-80 MHz band, log-RF waveforms within the 60-66 MHz band, an infra-red video camera, a high-sensitivity Watec video camera, two high-speed video cameras, and still cameras. We give an overview of the Sakurajima field program and present preliminary results using correlated LMA, waveforms, photographs and video recordings of volcanic lightning at Sakurajima volcano.

  20. Cellular and molecular basis of tooth eruption.

    Science.gov (United States)

    Wise, G E

    2009-05-01

    Tooth eruption requires the presence of a dental follicle (DF), alveolar bone resorption for an eruption pathway, and alveolar bone formation at the base of the bony crypt. The objectives of our investigations have been to determine how the DF regulates both the osteoclastogenesis and osteogenesis needed for eruption. Multiple experimental methods have been employed. The DF regulates osteoclastogenesis and osteogenesis by regulating the expression of critical genes in both a chronological and spatial fashion. In the rat 1st mandibular molar there is a major burst of osteoclastogenesis at day 3 postnatally and a minor burst at day 10. At day 3, the DF maximally expresses colony-stimulating factor-1 (CSF-1) to down-regulate the expression of osteoprotegerin (OPG) such that osteoclastogenesis can occur. At day 10, the minor burst of osteoclastogenesis is promoted by upregulation of vascular endothelial growth factor (VEGF) and RANKL in the DF. Spatially, the bone resorption is in the coronal portion of the bony crypt and genes such as RANKL are expressed more in the coronal region of the DF than in its basal one-half. For osteogenesis, bone formation begins at day 3 at the base of the bony crypt and maximal growth is at days 9-14. Osteo-inductive genes such as bone morphogenetic protein-2 (BMP-2) appear to promote this and are expressed more in the basal half of the DF than in the coronal. Conclusion - The osteoclastogenesis and osteogenesis needed for eruption are regulated by differential gene expression in the DF both chronologically and spatially.

  1. DYNAMICS OF MAGMA IN THE PLUMBING SYSTEM OF MT. ETNA VOLCANO, SICILY, ITALY: A CONTRIBUTION FROM PETROLOGIC DATA OF VOLCANICS ERUPTED FROM 2007 TO 2009

    Science.gov (United States)

    Corsaro, R.; Miraglia, L.

    2009-12-01

    initially drained the same reservoir feeding SEC activity. Conversely, starting from the end of May up to the end of June, the emission of a clearly more primitive magma evidences that the eruption is then sustained by the arrival of a different magma from depth, without any significant change of eruptive styles which maintains essentially effusive. In the following months up to the end of the eruption, no evidence of new magma inputs from depth exists and the differentiation of magma is mainly controlled by crystal fractionation. Why the long lasting 2008-09 Mt. Etna flank eruption started from a fissure located very close to the SEC crater, why it occurred just two days after the 10 May SEC paroxysm and, at the onset, poured out the same magma of 10 May fire fountain, is at present object of debate. The petrologic data evidence a link between the magma erupted during 10 May 2008 paroxysm and 2008-09 flank eruption, even if the eruptive styles of the two events are completely different. We will discuss too if a relationship between 10 May SEC paroxysm and 2008-09 flank eruption exists by integrating our petrologic data with information arising from geophysical monitoring of Mt. Etna volcano.

  2. Eruption products of the 1883 eruption of Krakatau and their final settlement

    Directory of Open Access Journals (Sweden)

    Izumi Yokoyama

    2015-06-01

    Full Text Available Firstly the volume of pyroclastic ejecta during the 1883 eruption of Krakatau is re-examined. To revise the volume of flow deposits, the author basically follows Verbeek’s observation while to estimate the fall deposits, as the last resort, the author assumes that volume ratios fall / flow are common to similar caldera eruptions, and the ratios determined by the caldera- forming eruptions of Novarupta and Pinatubo are applied to the Krakatau eruption. Verbeek’s estimation of the total volume of ejecta, 12 km3 is revised to 19 km3. This is significantly different from the volume of disrupted volcano edifice, 8 km3. Such a result does not support the predecessors’ hypothesis that calderas are formed by collapses of volcano edifices into magma reservoirs in replacement of the total ejecta. Through the discussion on the volume estimation of volcanic ejecta on and around Krakatau, the author recognizes that such estimation should be originally very difficult to attain enough accuracy. Much importance of “caldera deposits” to post-eruption settlements of the ejecta is emphasized. In relation to caldera formation, mechanical stability of a cavity in the crust is discussed. Lastly, upon the basis of subsurface structure, especially caldera deposits, a structural image of Krakatau caldera is presented.

  3. Drug eruptions from phenylbutazone in Jamu.

    Science.gov (United States)

    Giam, Y C; Tham, S N; Tan, T; Lim, A

    1986-01-01

    Drug eruptions from indeginous medicine is often difficult to diagnosis and confirm. It is known that a number of these now supplied by bomohs and Chinese sinsehs contain known drugs and are dispensed as tablets and capsules. We report 3 cases of adverse drug eruption to "Jamu", a Malay herb. A particular brand, "Jamu Indonesia, Toko Air Pancur", from Johor Bahru, Malaysia, is especially recommended for "sakit pinggang" or backache. The cases occurred between January and February 1985, and all had taken brown kidney shaped tablets. The adverse reactions were moderately severe. Two had erythroderma with hepatitis, and one, Steven Johnson Syndrome. Analysis of this jamu for analgesics led to the discovery of adulteration with phenylbutazone and diazepam. Records from local cases from 1974-1984 showed that 8 other patients, all Chinese had adverse cutaneous eruptions from phenylbutazone, oxybutazone and propyphenazone. The skin manifestations were erythroderma (2 cases), vasculitis (2 cases) and toxic epidermal necrolysis (4 cases). Those with toxic epidermal necrolysis had 100% mortality.

  4. Featured Image: A Filament Forms and Erupts

    Science.gov (United States)

    Kohler, Susanna

    2017-06-01

    This dynamic image of active region NOAA 12241 was captured by the Solar Dynamics Observatorys Atmospheric Imaging Assembly in December 2014. Observations of this region from a number of observatories and instruments recently presented by Jincheng Wang (University of Chinese Academy of Sciences) and collaborators reveal details about the formation and eruption of a long solar filament. Wang and collaborators show that the right part of the filament formed by magnetic reconnection between two bundles of magnetic field lines, while the left part formed as a result of shearing motion. When these two parts interacted, the filament erupted. You can read more about the teams results in the article linked below. Also, check out this awesome video of the filament formation and eruption, again by SDO/AIA:http://cdn.iopscience.com/images/0004-637X/839/2/128/Full/apjaa6bf3f1_video.mp4CitationJincheng Wang et al 2017 ApJ 839 128. doi:10.3847/1538-4357/aa6bf3

  5. Characterize Eruptive Processes at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    D. Krier

    2004-01-01

    The purpose of this scientific analysis report, ''Characterize Eruptive Processes at Yucca Mountain, Nevada'', is to present information about natural volcanic systems and the parameters that can be used to model their behavior. This information is used to develop parameter-value distributions appropriate for analysis of the consequences of volcanic eruptions through a repository at Yucca Mountain. This scientific analysis report provides information to four other reports: ''Number of Waste Packages Hit by Igneous Intrusion'', (BSC 2004 [DIRS 170001]); ''Atmospheric Dispersal and Deposition of Tephra from Potential Volcanic Eruption at Yucca Mountain, Nevada'' (BSC 2004 [DIRS 170026]); ''Dike/Drift Interactions'' (BSC 2004 [DIRS 170028]); ''Development of Earthquake Ground Motion Input for Preclosure Seismic Design and Postclosure Performance Assessment of a Geologic Repository at Yucca Mountain, NV'' (BSC 2004 [DIRS 170027], Section 6.5). This report is organized into seven major sections. This section addresses the purpose of this document. Section 2 addresses quality assurance, Section 3 the use of software, Section 4 identifies the requirements that constrain this work, and Section 5 lists assumptions and their rationale. Section 6 presents the details of the scientific analysis and Section 7 summarizes the conclusions reached

  6. Characterize Eruptive Processes at Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    D. Krier

    2004-10-04

    The purpose of this scientific analysis report, ''Characterize Eruptive Processes at Yucca Mountain, Nevada'', is to present information about natural volcanic systems and the parameters that can be used to model their behavior. This information is used to develop parameter-value distributions appropriate for analysis of the consequences of volcanic eruptions through a repository at Yucca Mountain. This scientific analysis report provides information to four other reports: ''Number of Waste Packages Hit by Igneous Intrusion'', (BSC 2004 [DIRS 170001]); ''Atmospheric Dispersal and Deposition of Tephra from Potential Volcanic Eruption at Yucca Mountain, Nevada'' (BSC 2004 [DIRS 170026]); ''Dike/Drift Interactions'' (BSC 2004 [DIRS 170028]); ''Development of Earthquake Ground Motion Input for Preclosure Seismic Design and Postclosure Performance Assessment of a Geologic Repository at Yucca Mountain, NV'' (BSC 2004 [DIRS 170027], Section 6.5). This report is organized into seven major sections. This section addresses the purpose of this document. Section 2 addresses quality assurance, Section 3 the use of software, Section 4 identifies the requirements that constrain this work, and Section 5 lists assumptions and their rationale. Section 6 presents the details of the scientific analysis and Section 7 summarizes the conclusions reached.

  7. Pre-eruptive and Co-eruptive Deformation due to the 2011 Shimoe-dake, Kirishima eruption in Kyushu, southern Japan

    Science.gov (United States)

    Zhang, Y.; Amelung, F.; Aoki, Y.

    2016-12-01

    To minimize the risks from volcanic eruptions, it's important to understand the precursory phenomenon and illustrate the behaviors during the eruptive cycle. However, examples with detailed observation are very limited due to the difficult access to volcanoes, or the sudden eruption before monitoring is possible. The 2011 eruption in Shimoe-dake, Kirishima is a well-monitored case among the few. Research from several different disciplines has been done, which provides an opportunity to integrate multiple tools and datasets for a more precise and comprehensive picture of this event. Here we start from the pre-eruptive and co-eruptive deformation from time series InSAR with multiple tracks of dataset to identify and locate deformation sources, then we integrate with continuous GPS observations to refine their temporal behavior and modeling constrains. Finally, we compare these geodetic results with seismic and geochemical studies to try to get more realistic modeling and interpretation. Our preliminary conclusion is as follows: (a) Two deformation sources are found: a deep disk-like magma chamber at 10 km depth 5 km away to the west of Shimoe-dake summit, corresponding to the 2011 magmatic eruption and its one year of pre-eruptive inflation; and a shallow sphere-shape hydrothermal source at 1.4 km depth beneath the summit, which corresponds to the 2008-2010 phreatic events. (b) The volume change associated to the pre-eruptive inflation is close in amplitude to the volume change associated to the co-eruptive deflation, indicating that all new magma accumulated into the magma chamber was transferred to the surface to feed the eruption. We could conclude that this magma chamber is not a large magma storage zone but acts more as a transfer zone between deep magma reservoir and surface.

  8. SOLAR MULTIPLE ERUPTIONS FROM A CONFINED MAGNETIC STRUCTURE

    International Nuclear Information System (INIS)

    Lee, Jeongwoo; Chae, Jongchul; Liu, Chang; Jing, Ju

    2016-01-01

    How eruption can recur from a confined magnetic structure is discussed based on the Solar Dynamics Observatory observations of the NOAA active region 11444, which produced three eruptions within 1.5 hr on 2012 March 27. The active region (AR) had the positive-polarity magnetic fields in the center surrounded by the negative-polarity fields around. Since such a distribution of magnetic polarity tends to form a dome-like magnetic fan structure confined over the AR, the multiple eruptions were puzzling. Our investigation reveals that this event exhibits several properties distinct from other eruptions associated with magnetic fan structures: (i) a long filament encircling the AR was present before the eruptions; (ii) expansion of the open–closed boundary (OCB) of the field lines after each eruption was suggestive of the growing fan-dome structure, and (iii) the ribbons inside the closed magnetic polarity inversion line evolved in response to the expanding OCB. It thus appears that in spite of multiple eruptions the fan-dome structure remained undamaged, and the closing back field lines after each eruption rather reinforced the fan-dome structure. We argue that the multiple eruptions could occur in this AR in spite of its confined magnetic structure because the filament encircling the AR was adequate for slipping through the magnetic separatrix to minimize the damage to its overlying fan-dome structure. The result of this study provides a new insight into the productivity of eruptions from a confined magnetic structure.

  9. How does tooth eruption relate to vertical mandibular growth displacement?

    Science.gov (United States)

    Liu, Sean Shih-Yao; Buschang, Peter H

    2011-06-01

    Our objectives were to investigate the eruptive patterns of the mandibular teeth and assess their associations with mandibular growth displacements. Cephalograms for a mixed-longitudinal sample of 124 French-Canadian girls were evaluated between 10 and 15 years of age. Vertical mandibular displacement and mandibular eruption were evaluated by using cranial and mandibular superimpositions, respectively. Multilevel modeling procedures were used to estimate each subject's growth change over time. Stepwise multiple regressions were used to determine the amount and relative magnitudes of variations in mandibular eruption explained by mandibular growth displacement, controlling for vertical maxillary tooth movements. Cubic polynomial models explained between 91% and 98% of the variations in eruption and vertical growth displacement. All curves showed acceleration of eruption until approximately 12 years of age, after which eruption decelerated. The eruption of the mandibular teeth demonstrated greater relative variability than did vertical mandibular growth displacements. Independent of the overall movements of the maxillary molars, inferior mandibular growth displacement explained approximately 54% of the variation in mandibular molar eruption between 10.5 and 14.5 years of age. Inferior mandibular growth displacement and dental eruption followed similar patterns of change during adolescence. Based on their associations and the differences in variability identified, mandibular eruption appears to compensate for or adapt to growth displacements. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  10. Enhanced ice sheet melting driven by volcanic eruptions during the last deglaciation.

    Science.gov (United States)

    Muschitiello, Francesco; Pausata, Francesco S R; Lea, James M; Mair, Douglas W F; Wohlfarth, Barbara

    2017-10-24

    Volcanic eruptions can impact the mass balance of ice sheets through changes in climate and the radiative properties of the ice. Yet, empirical evidence highlighting the sensitivity of ancient ice sheets to volcanism is scarce. Here we present an exceptionally well-dated annual glacial varve chronology recording the melting history of the Fennoscandian Ice Sheet at the end of the last deglaciation (∼13,200-12,000 years ago). Our data indicate that abrupt ice melting events coincide with volcanogenic aerosol emissions recorded in Greenland ice cores. We suggest that enhanced ice sheet runoff is primarily associated with albedo effects due to deposition of ash sourced from high-latitude volcanic eruptions. Climate and snowpack mass-balance simulations show evidence for enhanced ice sheet runoff under volcanically forced conditions despite atmospheric cooling. The sensitivity of past ice sheets to volcanic ashfall highlights the need for an accurate coupling between atmosphere and ice sheet components in climate models.

  11. Petrological and seismic precursors of the paroxysmal phase of the last Vesuvius eruption on March 1944

    Science.gov (United States)

    Pappalardo, Lucia; D'Auria, Luca; Cavallo, Andrea; Fiore, Stefano

    2014-09-01

    Abrupt transitions in style and intensity are common during volcanic eruptions, with an immediate impact on the surrounding territory and its population. Defining the factors trigger such sudden shifts in the eruptive behavior as well as developing methods to predict such changes during volcanic crises are crucial goals in volcanology. In our research, the combined investigation of both petrological and seismic indicators has been applied for the first time to a Vesuvius eruption, that of March 1944 that caused the present dormant state of the volcano. Our results contribute to elucidate the evolution of the conduit dynamics that generated a drastic increase in the Volcanic Explosivity Index, associated to the ejection of huge amount of volcanic ash. Remarkably, our study shows that the main paroxysm was announced by robust changes in petrology consistent with seismology, thus suggesting that the development of monitoring methods to assess the nature of ejected juvenile material combined with conventional geophysical techniques can represent a powerful tool for forecasting the evolution of an eruption towards violent behavior. This in turn is a major goal in volcanology because this evidence can help decision-makers to implement an efficient safety strategy during the emergency (scale and pace of evacuation).

  12. Ground deformation before the 2015 eruptions of Cotopaxi volcano detected by InSAR

    Science.gov (United States)

    Morales Rivera, Anieri M.; Amelung, Falk; Mothes, Patricia; Hong, Sang-Hoon; Nocquet, Jean-Mathieu; Jarrin, Paul

    2017-07-01

    Cotopaxi volcano started a period of volcanic unrest in April 2015 that led to a series of eruptions between August and November 2015. We use COSMO-SkyMed Interferometric Synthetic Aperture Radar supported by continuous GPS observations spanning the period of 2014-2016 to obtain time-dependent ground deformation data over Cotopaxi volcano related to the period of unrest and onset of eruptions. We find evidence of precursory deformation, with a maximum uplift on the western flank of 3.4 cm from April to August 2015. Deformation is explained by an inclined sheet intrusion located a few km southwest of the summit with an opening volume of 6.8 × 106 m3, extending from a depth of 12.1 km and shallowing to 5.5 km below the summit, that contributed to internal edifice growth. The temporal coincidence of deformation prior to the eruptions potentially suggests that short-term eruptions at Cotopaxi are partly controlled by episodic edifice growth.

  13. Hubble Captures Volcanic Eruption Plume From Io

    Science.gov (United States)

    1997-01-01

    The Hubble Space Telescope has snapped a picture of a 400-km-high (250-mile-high) plume of gas and dust from a volcanic eruption on Io, Jupiter's large innermost moon.Io was passing in front of Jupiter when this image was taken by the Wide Field and Planetary Camera 2 in July 1996. The plume appears as an orange patch just off the edge of Io in the eight o'clock position, against the blue background of Jupiter's clouds. Io's volcanic eruptions blasts material hundreds of kilometers into space in giant plumes of gas and dust. In this image, material must have been blown out of the volcano at more than 2,000 mph to form a plume of this size, which is the largest yet seen on Io.Until now, these plumes have only been seen by spacecraft near Jupiter, and their detection from the Earth-orbiting Hubble Space Telescope opens up new opportunities for long-term studies of these remarkable phenomena.The plume seen here is from Pele, one of Io's most powerful volcanos. Pele's eruptions have been seen before. In March 1979, the Voyager 1 spacecraft recorded a 300-km-high eruption cloud from Pele. But the volcano was inactive when the Voyager 2 spacecraft flew by Jupiter in July 1979. This Hubble observation is the first glimpse of a Pele eruption plume since the Voyager expeditions.Io's volcanic plumes are much taller than those produced by terrestrial volcanos because of a combination of factors. The moon's thin atmosphere offers no resistance to the expanding volcanic gases; its weak gravity (one-sixth that of Earth) allows material to climb higher before falling; and its biggest volcanos are more powerful than most of Earth's volcanos.This image is a contrast-enhanced composite of an ultraviolet image (2600 Angstrom wavelength), shown in blue, and a violet image (4100 Angstrom wavelength), shown in orange. The orange color probably occurs because of the absorption and/or scattering of ultraviolet light in the plume. This light from Jupiter passes through the plume and is

  14. Eruptions at Lone Star Geyser, Yellowstone National Park, USA, part 1: energetics and eruption dynamics

    Science.gov (United States)

    Karlstrom, Leif; Hurwitz, Shaul; Sohn, Robert; Vandemeulebrouck, Jean; Murphy, Fred; Rudolph, Maxwell L.; Johnston, Malcolm J.S.; Manga, Michael; McCleskey, R. Blaine

    2013-01-01

    Geysers provide a natural laboratory to study multiphase eruptive processes. We present results from a four–day experiment at Lone Star Geyser in Yellowstone National Park, USA. We simultaneously measured water discharge, acoustic emissions, infraredintensity, and visible and infrared video to quantify the energetics and dynamics of eruptions, occurring approximately every three hours. We define four phases in the eruption cycle: 1) a 28 ± 3 minute phase with liquid and steam fountaining, with maximum jet velocities of 16–28 m s− 1, steam mass fraction of less than ∼ 0.01. Intermittently choked flow and flow oscillations with periods increasing from 20 to 40 s are coincident with a decrease in jet velocity and an increase of steam fraction; 2) a 26 ± 8 minute post–eruption relaxation phase with no discharge from the vent, infrared (IR) and acoustic power oscillations gliding between 30 and 40 s; 3) a 59 ± 13 minute recharge period during which the geyser is quiescent and progressively refills, and 4) a 69 ± 14 minute pre–play period characterized by a series of 5–10 minute–long pulses of steam, small volumes of liquid water discharge and 50–70 s flow oscillations. The erupted waters ascend froma 160 − 170° C reservoir and the volume discharged during the entire eruptive cycle is 20.8 ± 4.1 m3. Assuming isentropic expansion, we calculate a heat output from the geyser of 1.4–1.5 MW, which is < 0.1% of the total heat output from Yellowstone Caldera.

  15. A comparison study of a solar active-region eruptive filament and a neighboring non-eruptive filament

    International Nuclear Information System (INIS)

    Jiang, Chao-Wei; Feng, Xue-Shang; Wu, Shi-Tsan; Hu, Qiang

    2016-01-01

    Solar active region (AR) 11283 is a very magnetically complex region and it has produced many eruptions. However, there exists a non-eruptive filament in the plage region just next to an eruptive one in the AR, which gives us an opportunity to perform a comparison analysis of these two filaments. The coronal magnetic field extrapolated using our CESE–MHD–NLFFF code reveals that two magnetic flux ropes (MFRs) exist in the same extrapolation box supporting these two filaments, respectively. Analysis of the magnetic field shows that the eruptive MFR contains a bald-patch separatrix surface (BPSS) cospatial very well with a pre-eruptive EUV sigmoid, which is consistent with the BPSS model for coronal sigmoids. The magnetic dips of the non-eruptive MFRs match Hα observation of the non-eruptive filament strikingly well, which strongly supports the MFR-dip model for filaments. Compared with the non-eruptive MFR/filament (with a length of about 200 Mm), the eruptive MFR/filament is much smaller (with a length of about 20 Mm), but it contains most of the magnetic free energy in the extrapolation box and holds a much higher free energy density than the non-eruptive one. Both the MFRs are weakly twisted and cannot trigger kink instability. The AR eruptive MFR is unstable because its axis reaches above a critical height for torus instability, at which the overlying closed arcades can no longer confine the MFR stably. On the contrary, the quiescent MFR is very firmly held by its overlying field, as its axis apex is far below the torus-instability threshold height. Overall, this comparison investigation supports that an MFR can exist prior to eruption and the ideal MHD instability can trigger an MFR eruption. (paper)

  16. A comparison study of a solar active-region eruptive filament and a neighboring non-eruptive filament

    Science.gov (United States)

    Jiang, Chao-Wei; Wu, Shi-Tsan; Feng, Xue-Shang; Hu, Qiang

    2016-01-01

    Solar active region (AR) 11283 is a very magnetically complex region and it has produced many eruptions. However, there exists a non-eruptive filament in the plage region just next to an eruptive one in the AR, which gives us an opportunity to perform a comparison analysis of these two filaments. The coronal magnetic field extrapolated using our CESE-MHD-NLFFF code reveals that two magnetic flux ropes (MFRs) exist in the same extrapolation box supporting these two filaments, respectively. Analysis of the magnetic field shows that the eruptive MFR contains a bald-patch separatrix surface (BPSS) cospatial very well with a pre-eruptive EUV sigmoid, which is consistent with the BPSS model for coronal sigmoids. The magnetic dips of the non-eruptive MFRs match Hα observation of the non-eruptive filament strikingly well, which strongly supports the MFR-dip model for filaments. Compared with the non-eruptive MFR/filament (with a length of about 200 Mm), the eruptive MFR/filament is much smaller (with a length of about 20 Mm), but it contains most of the magnetic free energy in the extrapolation box and holds a much higher free energy density than the non-eruptive one. Both the MFRs are weakly twisted and cannot trigger kink instability. The AR eruptive MFR is unstable because its axis reaches above a critical height for torus instability, at which the overlying closed arcades can no longer confine the MFR stably. On the contrary, the quiescent MFR is very firmly held by its overlying field, as its axis apex is far below the torus-instability threshold height. Overall, this comparison investigation supports that an MFR can exist prior to eruption and the ideal MHD instability can trigger an MFR eruption.

  17. Evaluating Changes in Pre-Eruptive Conditions of Explosively and Effusively Erupted Intermediate Magmas

    Science.gov (United States)

    Casaus, J. G.; Waters, L. E.; Frey, H. M.; Manon, M. R. F.

    2017-12-01

    Dominica is known for its voluminous eruptions of andesitic and dacitic magmas, and provides a case study for testing for differences in the magmatic systems sourcing explosive and effusive intermediate volcanics. Here, we conduct a detailed petrologic study to evaluate changes in the pre-eruptive magmatic conditions between the eruption of the Layou ignimbrite (LI) and its corresponding resurgent dome, Morne Trois Piton (MTP). Point counts reveal that the LI contains 21% crystals and is multiply saturated in seven phenocrystic phases (plagioclase + hornblende + clinopyroxene +orthopyroxene + ilmenite + magnetite + quartz). The MTP dome is intermediate in composition with light and dark grey banding with mafic enclaves. MTP contains 50% crystals and a phase assemblage identical to LI with a few notable distinctions. Hornblende crystals in the dome are significantly reacted, and quartz occurs in a greater abundance and size. Application of a two-oxide geo-thermometer results in an average pre-eruptive temperature of 769 ± 12°C and average oxygen fugacity of -0.1 ± 0.1 ΔNNO (relative to the NNO buffer) for LI. Despite differences in color, the banded lavas yielded similar pre-eruptive temperatures and fO2, with light grey at 813 ± 32 °C and average fO2 of 0.4 ± 0.1 ΔNNO, and dark grey at 822± 27 °C and fO2 of 0.3 ± 0.2 ΔNNO. Water contents are calculated by incorporating the whole rock and interstitial glass compositions into a plagioclase liquid hygrometer model along with pre-eruptive temperatures and plagioclase compositions. H2O contents for the Layou ignimbrite range from 6.4 to 8.7 wt%, whereas water contents for all Morne Trois Piton lava range from 7.2-8.5 wt%. Pressures of crystallization are estimated using a solubility model and the water contents derived from the hygrometer and are ≥3kb (≥10km) for all samples. The main difference between the explosive LI and effusive MTP is that the dome shows signs of mingling of light and dark grey

  18. Observing eruptions of gas-rich compressible magmas from space.

    Science.gov (United States)

    Kilbride, Brendan McCormick; Edmonds, Marie; Biggs, Juliet

    2016-12-21

    Observations of volcanoes from space are a critical component of volcano monitoring, but we lack quantitative integrated models to interpret them. The atmospheric sulfur yields of eruptions are variable and not well correlated with eruption magnitude and for many eruptions the volume of erupted material is much greater than the subsurface volume change inferred from ground displacements. Up to now, these observations have been treated independently, but they are fundamentally linked. If magmas are vapour-saturated before eruption, bubbles cause the magma to become more compressible, resulting in muted ground displacements. The bubbles contain the sulfur-bearing vapour injected into the atmosphere during eruptions. Here we present a model that allows the inferred volume change of the reservoir and the sulfur mass loading to be predicted as a function of reservoir depth and the magma's oxidation state and volatile content, which is consistent with the array of natural data.

  19. Impacts of a Pinatubo-size volcanic eruption on ENSO

    KAUST Repository

    Predybaylo, Evgeniya

    2017-01-16

    Observations and model simulations of the climate responses to strong explosive low-latitude volcanic eruptions suggest a significant increase in the likelihood of El Niño during the eruption and posteruption years, though model results have been inconclusive and have varied in magnitude and even sign. In this study, we test how this spread of responses depends on the initial phase of El Niño-Southern Oscillation (ENSO) in the eruption year and on the eruption\\'s seasonal timing. We employ the Geophysical Fluid Dynamics Laboratory CM2.1 global coupled general circulation model to investigate the impact of the Pinatubo 1991 eruption, assuming that in 1991 ENSO would otherwise be in central or eastern Pacific El Niño, La Niña, or neutral phases. We obtain statistically significant El Niño responses in a year after the eruption for all cases except La Niña, which shows no response in the eastern equatorial Pacific. The eruption has a weaker impact on eastern Pacific El Niños than on central Pacific El Niños. We find that the ocean dynamical thermostat and (to a lesser extent) wind changes due to land-ocean temperature gradients are the main feedbacks affecting El Niño development after the eruption. The El Niño responses to eruptions occurring in summer are more pronounced than for winter and spring eruptions. That the climate response depends on eruption season and initial ENSO phase may help to reconcile apparent inconsistencies among previous studies.

  20. Failed magmatic eruptions: Late-stage cessation of magma ascent

    Science.gov (United States)

    Moran, S.C.; Newhall, C.; Roman, D.C.

    2011-01-01

    When a volcano becomes restless, a primary question is whether the unrest will lead to an eruption. Here we recognize four possible outcomes of a magmatic intrusion: "deep intrusion", "shallow intrusion", "sluggish/viscous magmatic eruption", and "rapid, often explosive magmatic eruption". We define "failed eruptions" as instances in which magma reaches but does not pass the "shallow intrusion" stage, i. e., when magma gets close to, but does not reach, the surface. Competing factors act to promote or hinder the eventual eruption of a magma intrusion. Fresh intrusion from depth, high magma gas content, rapid ascent rates that leave little time for enroute degassing, opening of pathways, and sudden decompression near the surface all act to promote eruption, whereas decreased magma supply from depth, slow ascent, significant enroute degassing and associated increases in viscosity, and impingement on structural barriers all act to hinder eruption. All of these factors interact in complex ways with variable results, but often cause magma to stall at some depth before reaching the surface. Although certain precursory phenomena, such as rapidly escalating seismic swarms or rates of degassing or deformation, are good indicators that an eruption is likely, such phenomena have also been observed in association with intrusions that have ultimately failed to erupt. A perpetual difficulty with quantifying the probability of eruption is a lack of data, particularly on instances of failed eruptions. This difficulty is being addressed in part through the WOVOdat database. Papers in this volume will be an additional resource for scientists grappling with the issue of whether or not an episode of unrest will lead to a magmatic eruption.

  1. Erupted complex composite odontoma: Report of two atypical cases

    Directory of Open Access Journals (Sweden)

    Preeti Tomar Bhattacharya

    2015-01-01

    Full Text Available Odontomas are nonaggressive, hamartomatous developmental malformations of odontogenic origin. They are considered one of the most common odontogenic lesions composed by diverse dental tissues. They may interfere with the eruption of an associated tooth and are more prevalent in the posterior mandible. The eruption of a complex odontoma into the oral cavity is rare. Here, we report such two rare cases of gigantic erupted complex composite odontomas.

  2. Beyond eruptive scenarios: assessing tephra fallout hazard from Neapolitan volcanoes

    Science.gov (United States)

    Sandri, Laura; Costa, Antonio; Selva, Jacopo; Tonini, Roberto; Macedonio, Giovanni; Folch, Arnau; Sulpizio, Roberto

    2016-01-01

    Assessment of volcanic hazards is necessary for risk mitigation. Typically, hazard assessment is based on one or a few, subjectively chosen representative eruptive scenarios, which use a specific combination of eruptive sizes and intensities to represent a particular size class of eruption. While such eruptive scenarios use a range of representative members to capture a range of eruptive sizes and intensities in order to reflect a wider size class, a scenario approach neglects to account for the intrinsic variability of volcanic eruptions, and implicitly assumes that inter-class size variability (i.e. size difference between different eruptive size classes) dominates over intra-class size variability (i.e. size difference within an eruptive size class), the latter of which is treated as negligible. So far, no quantitative study has been undertaken to verify such an assumption. Here, we adopt a novel Probabilistic Volcanic Hazard Analysis (PVHA) strategy, which accounts for intrinsic eruptive variabilities, to quantify the tephra fallout hazard in the Campania area. We compare the results of the new probabilistic approach with the classical scenario approach. The results allow for determining whether a simplified scenario approach can be considered valid, and for quantifying the bias which arises when full variability is not accounted for. PMID:27067389

  3. High-resolution Observations of Sympathetic Filament Eruptions by NVST

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shangwei; Su, Yingna; Zhou, Tuanhui; Ji, Haisheng [Key Laboratory for Dark Matter and Space Science, Purple Mountain Observatory, CAS, Nanjing 210008 (China); Van Ballegooijen, Adriaan [5001 Riverwood Avenue, Sarasota, FL 34231 (United States); Sun, Xudong, E-mail: ynsu@pmo.ac.cn [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)

    2017-07-20

    We investigate two sympathetic filament eruptions observed by the New Vacuum Solar Telescope on 2015 October 15. The full picture of the eruptions is obtained from the corresponding Solar Dynamics Observatory ( SDO )/Atmospheric Imaging Assembly (AIA) observations. The two filaments start from active region NOAA 12434 in the north and end in one large quiescent filament channel in the south. The left filament erupts first, followed by the right filament eruption about 10 minutes later. Clear twist structure and rotating motion are observed in both filaments during the eruption. Both eruptions failed, since the filaments first rise up, then flow toward the south and merge into the southern large quiescent filament. We also observe repeated activations of mini filaments below the right filament after its eruption. Using magnetic field models constructed based on SDO /HMI magnetograms via the flux rope insertion method, we find that the left filament eruption is likely to be triggered by kink instability, while the weakening of overlying magnetic fields due to magnetic reconnection at an X-point between the two filament systems might play an important role in the onset of the right filament eruption.

  4. Tic Tac TOE: Effects of Predictability and Importance on Acoustic Prominence in Language Production

    Science.gov (United States)

    Watson, Duane G.; Arnold, Jennifer E.; Tanenhaus, Michael K.

    2008-01-01

    Importance and predictability each have been argued to contribute to acoustic prominence. To investigate whether these factors are independent or two aspects of the same phenomenon, naive participants played a verbal variant of Tic Tac Toe. Both importance and predictability contributed independently to the acoustic prominence of a word, but in…

  5. 77 FR 3779 - Guidance for Industry on Product Name Placement, Size, and Prominence in Advertising and...

    Science.gov (United States)

    2012-01-25

    ... Advertising and Promotional Labeling; Availability AGENCY: Food and Drug Administration, HHS. ACTION: Notice... entitled ``Product Name Placement, Size, and Prominence in Advertising and Promotional Labeling.'' The..., prominence, and frequency in promotional labeling and advertising for prescription human and animal drugs and...

  6. The relative cueing power of F0 and duration in German prominence perception

    DEFF Research Database (Denmark)

    Niebuhr, Oliver; Winkler, Jana

    2017-01-01

    Previous studies showed for German and other (West) Germanic language, including English, that perceived syllable prominence is primarily controlled by changes in duration and F0, with the latter cue being more powerful than the former. Our study is an initial approach to develop this prominence ...

  7. Microbiological characterization of post-eruption "snowblower" vents at Axial Seamount, Juan de Fuca Ridge

    Directory of Open Access Journals (Sweden)

    Julie L Meyer

    2013-06-01

    Full Text Available Microbial processes within the subseafloor can be examined during the ephemeral and uncommonly observed phenomena known as snowblower venting. Snowblowers are characterized by the large quantity of white floc that is expelled from the seafloor following mid-ocean ridge eruptions. During these eruptions, rapidly cooling lava entrains seawater and hydrothermal fluids enriched in geochemical reactants, creating a natural bioreactor that supports a subseafloor microbial bloom. Previous studies hypothesized that the eruption-associated floc is made by sulfide-oxidizing bacteria; however, the microbes involved were never identified. Here we present the first molecular analysis combined with microscopy of microbial communities in snowblower vents from samples collected shortly after the 2011 eruption at Axial Seamount, an active volcano on the Juan de Fuca Ridge. We obtained fluid samples and white flocculent material from active snowblower vents as well as orange flocculent material found on top of newly formed lava flows. Both flocculent types revealed diverse cell types and particulates when examined by phase contrast and scanning electron microscopy. Distinct archaeal and bacterial communities were detected in each sample type through Illumina tag sequencing of 16S rRNA genes and through sequencing of the sulfide oxidation gene, soxB. In fluids and white floc, the dominant bacteria were sulfur-oxidizing Epsilonproteobacteria and the dominant archaea were thermophilic Methanococcales. In contrast, the dominant organisms in the orange floc were Gammaproteobacteria and Thaumarchaeota Marine Group I. In all samples, bacteria greatly outnumbered archaea. The presence of anaerobic methanogens and microaerobic Epsilonproteobacteria in snowblower communities provides evidence that these blooms are seeded by subseafloor microbes, rather than from microbes in bottom seawater. These eruptive events thus provide a unique opportunity to observe subseafloor

  8. Karymsky volcano eruptive plume properties based on MISR multi-angle imagery and the volcanological implications

    Directory of Open Access Journals (Sweden)

    V. J. B. Flower

    2018-03-01

    Full Text Available Space-based operational instruments are in unique positions to monitor volcanic activity globally, especially in remote locations or where suborbital observing conditions are hazardous. The Multi-angle Imaging SpectroRadiometer (MISR provides hyper-stereo imagery, from which the altitude and microphysical properties of suspended atmospheric aerosols can be derived. These capabilities are applied to plumes emitted at Karymsky volcano from 2000 to 2017. Observed plumes from Karymsky were emitted predominantly to an altitude of 2–4 km, with occasional events exceeding 6 km. MISR plume observations were most common when volcanic surface manifestations, such as lava flows, were identified by satellite-based thermal anomaly detection. The analyzed plumes predominantly contained large (1.28 µm effective radius, strongly absorbing particles indicative of ash-rich eruptions. Differences between the retrievals for Karymsky volcano's ash-rich plumes and the sulfur-rich plumes emitted during the 2014–2015 eruption of Holuhraun (Iceland highlight the ability of MISR to distinguish particle types from such events. Observed plumes ranged from 30 to 220 km in length and were imaged at a spatial resolution of 1.1 km. Retrieved particle properties display evidence of downwind particle fallout, particle aggregation and chemical evolution. In addition, changes in plume properties retrieved from the remote-sensing observations over time are interpreted in terms of shifts in eruption dynamics within the volcano itself, corroborated to the extent possible with suborbital data. Plumes emitted at Karymsky prior to 2010 display mixed emissions of ash and sulfate particles. After 2010, all plumes contain consistent particle components, indicative of entering an ash-dominated regime. Post-2010 event timing, relative to eruption phase, was found to influence the optical properties of observed plume particles, with light absorption varying in a consistent

  9. Dome collapse eruption in Tatun Volcanic Group near metropolitan Taipei, Taiwan at ~6 kyrs

    Science.gov (United States)

    Chen, C.; Lee, T.

    2010-12-01

    The Tatun Volcanic Group (TVG) is located in the north of metropolitan Taipei, Taiwan. Over 6 million inhabitants are living in Taipei City and suburban area. Another critical issue is an international airport and two nuclear power plants are lying at the foot of the TVG. If the TGV will be re-active, the serious hazard for human lives and economies in this area will definitely occur. Understanding the youngest eruption history of the TVG will be much important for prediction the future activity of eruption. The core was collected from the Dream Lake at the eastern slop of Cising Mt.. Total 21 samples from depth 190 cm to 231.5 cm have been tested. Comparison of chemical compositions of glass and minerals in the volcanic clasts with those of lava around TVG, they clearly showed that the volcanic clasts can be correlated with the eruption of the closest Cising Mt. According to the radiocarbon (C-14) age of core sample at the depth 225 cm, the age was extrapolated around 6150 yrs ca. C-14 B.P.. Moreover, the respiratory cristobalite in the volcanic clasts were firstly identified by the identical morphology, chemical composition and Laser Raman Spectrometry (LRS). The crystalline silica was produced by vapor-phase crystallization and devitrification in the andesite lava dome and volcanic ash generated by pyroclastic flows formed by lava dome collapse in Soufriere Hills volcano, Montserrat (Baxter et al.,1999). These new evidence demonstrated that there would probably have the lava dome collapse eruptions in the TVG in the last 6 kyrs. The result in this paper also sustained that the landslide caused by the weak phreatic eruption within the last 6000 yrs in the TVG (Belousov et al., 2010). It must further be noted that an efficient program of the volcanic hazard reduction should be practiced for the metropolitan Taipei and suburban area.

  10. Human survival in volcanic eruptions: Thermal injuries in pyroclastic surges, their causes, prognosis and emergency management.

    Science.gov (United States)

    Baxter, Peter J; Jenkins, Susanna; Seswandhana, Rosadi; Komorowski, Jean-Christophe; Dunn, Ken; Purser, David; Voight, Barry; Shelley, Ian

    2017-08-01

    This study of burns patients from two eruptions of Merapi volcano, Java, in 1994 and 2010, is the first detailed analysis to be reported of thermal injuries in a large series of hospitalised victims of pyroclastic surges, one of the most devastating phenomena in explosive eruptions. Emergency planners in volcanic crises in populated areas have to integrate the health sector into disaster management and be aware of the nature of the surge impacts and the types of burns victims to be expected in a worst scenario, potentially in numbers and in severity that would overwhelm normal treatment facilities. In our series, 106 patients from the two eruptions were treated in the same major hospital in Yogyakarta and a third of these survived. Seventy-eight per cent were admitted with over 40% TBSA (total body surface area) burns and around 80% of patients were suspected of having at least some degree of inhalation injury as well. Thirty five patients suffered over 80% TBSA burns and only one of these survived. Crucially, 45% of patients were in the 40-79% TBSA range, with most suspected of suffering from inhalation injury, for whom survival was most dependent on the hospital treatment they received. After reviewing the evidence from recent major eruptions and outlining the thermal hazards of surges, we relate the type and severity of the injuries of these patients to the temperatures and dynamics of the pyroclastic surges, as derived from the environmental impacts and associated eruption processes evaluated in our field surveys and interviews conducted by our multi-disciplinary team. Effective warnings, adequate evacuation measures, and political will are all essential in volcanic crises in populated areas to prevent future catastrophes on this scale. Copyright © 2017 Elsevier Ltd and ISBI. All rights reserved.

  11. [Eruptive pseudoangiomatosis in infant and newborns].

    Science.gov (United States)

    Guillot, B; Chraibi, H; Girard, C; Dereure, O; Lalande, M; Bessis, D

    2005-12-01

    Eruptive pseudoangiomatosis was first described in children in the form of an acute non-pruritic macular or papular rash that fades on application of a glass test and resolves within several days. Viral aetiology is suspected but has never been demonstrated to date. We discuss seven cases of infants presenting this disease: 5 boys and 2 girls aged 8 days to 16 months. The rash presented typical clinical features in all cases and affected the face and limbs in 6 of the 7 subjects. In one child, involvement of the face and back was observed with sparing of the limbs. The rash occurred after an episode of rhinolaryngeal infection in 3 cases and after gastrointestinal infection in 1 case. Spontaneous resolution was seen within 3 to 10 days in 6 patients although a longer course lasting over 9 months was observed in one infant. In another patient, the rash appeared after surgery for mesoblastic nephroma. In one child, a similar rash was seen in both parents. Screening for infectious agents was negative for the two children from whom samples were obtained. This series of paediatric cases of eruptive pseudoangiomatosis is characterised by the very young age of one of the children, coexistence of the condition with a renal tumour in another child, the familial nature of the rash in a third child and unusually long disease duration in the final child. However, this series did not allow identification of the causative infectious agent or agents. Probably, as with other syndromes such as Giannotti-Crosti syndrome or "gloves and socks" syndrome, eruptive pseudoangiomatosis forms a clinical picture common to a non-specific viral infection.

  12. Magma dynamics during the 2007 Stromboli eruption (Aeolian Islands, Italy): Mineralogical, geochemical and isotopic data

    Science.gov (United States)

    Landi, P.; Corsaro, R. A.; Francalanci, L.; Civetta, L.; Miraglia, L.; Pompilio, M.; Tesoro, R.

    2009-05-01

    After the 6 month-long effusive event of 2002-2003, a new lava effusion occurred at Stromboli between 27 February and 2 April 2007. Despite the different durations, approximately the same volume of magma was emitted in both eruptions, in the order of 10 7 m 3. A paroxysmal eruption occurred at the summit craters in both the 2002-2003 and 2007 episodes, during which a significant amount of low porphyritic (LP), volatile-rich magma was erupted. In both cases, the paroxysm did not interrupt the lava emission. Here, we present compositional data, including texture, mineralogy, chemistry and Sr and Nd isotope ratios of bulk-rock, groundmass and separated minerals of lavas erupted in 2007, together with chemistry and Sr and Nd isotope composition of the pumices emitted during the 15 March paroxysm. As a whole, the lavas have the same texture and chemistry that characterize the highly porphyritic (HP) products usually erupted at Stromboli during normal Strombolian activity and effusive events. Compared to the previous HP products, the 2007 lavas show minor but systematic mineralogical and isotopic variations which are consistent with a modest increase of the magma supply rate of the volcano. Compositional variations during the entire duration of the event are very modest. Glass chemistry changes in lavas erupted in the second half of March can be explained by the minor mixing between the volatile-rich LP magma rising through the shallow magmatic system during the 15 March paroxysm and the degassed residing HP magma. A first conclusion of this study is that there is no compositional evidence supporting major changes in the magma dynamics of the volcano accompanying the effusive activity, as also suggested for the 2002-2003 event. The activity of Stromboli is controlled by a steady state feeding system in which refilling, mixing, degassing and crystallization at shallow level continuously operate, with modest oscillations in the magma supply rate. Switching between normal

  13. Modeling of prominence threads in magnetic fields: Levitation by incompressible MHD waves

    Science.gov (United States)

    Pécseli, Hans; Engvold, OddbjØrn

    2000-05-01

    The nature of thin, highly inclined threads observed in quiescent prominences has puzzled solar physicists for a long time. When assuming that the threads represent truly inclined magnetic fields, the supporting mechanism of prominence plasma against gravity has remained an open issue. This paper examines the levitation of prominence plasma exerted by weakly damped MHD waves in nearly vertical magnetic flux tubes. It is shown that the wave damping, and resulting `radiation pressure', caused predominantly by ion-neutral collisions in the `cold' prominence plasma, may balance the acceleration of gravity provided the oscillation frequency is ω~ 2 rad s^-1 (f~0.5 Hz). Such short wave periods may be the result of small-scale magnetic reconnections in the highly fragmentary magnetic field of quiescent prominences. In the proposed model, the wave induced levitation acts predominantly on plasma - neutral gas mixtures.

  14. Physics of Solar Prominences: I-Spectral Diagnostics and Non-LTE Modelling

    Science.gov (United States)

    Labrosse, N.; Heinzel, P.; Vial, J.-C,; Kucera, T.; Parenti, S.; Gunar, S.; Schmieder, B.; Kilper, G.

    2010-01-01

    This review paper outlines background information and covers recent advances made via the analysis of spectra and images of prominence plasma and the increased sophistication of non-LTE (i.e. when there is a departure from Local Thermodynamic Equilibrium) radiative transfer models. We first describe the spectral inversion techniques that have been used to infer the plasma parameters important for the general properties of the prominence plasma in both its cool core and the hotter prominence-corona transition region. We also review studies devoted to the observation of bulk motions of the prominence plasma and to the determination of prominence mass. However, a simple inversion of spectroscopic data usually fails when the lines become optically thick at certain wavelengths. Therefore, complex

  15. Paradoxical aging in HIV: immune senescence of B Cells is most prominent in young age

    Science.gov (United States)

    George, Varghese K.; de Armas, Lesley R.; Pahwa, Rajendra; Sanchez, Celeste M.; Pallin, Maria Fernanda; Pan, Li; Cotugno, Nicola; Dickinson, Gordon; Rodriguez, Allan; Fischl, Margaret; Alcaide, Maria; Gonzalez, Louis; Palma, Paolo; Pahwa, Savita

    2017-01-01

    Combination antiretroviral therapies (cART) can lead to normal life expectancy in HIV-infected persons, and people aged >50 yrs represent the fastest growing HIV group. Although HIV and aging are independently associated with impaired humoral immunity, immune status in people aging with HIV is relatively unexplored. In this study influenza vaccination was used to probe age associated perturbations in the B cell compartment of HIV-negative “healthy controls” (HC) and virologically controlled HIV-infected participants on cART (HIV) (n=124), grouped by age as young (<40 yrs), middle-aged (40-59yrs) or old (≥60 yrs). H1N1 antibody response at d21 post-vaccination correlated inversely with age in both HC and HIV. Immunophenotyping of cryopreserved PBMC demonstrated increased frequencies of double negative B cells and decreased plasmablasts in old compared to young HC. Remarkably, young HIV were different from young HC but similar to old HC in B cell phenotype, influenza specific spontaneous (d7) or memory (d21) antibody secreting cells. We conclude that B cell immune senescence is a prominent phenomenon in young HIV in comparison to young HC, but distinctions between old HIV and old HC are less evident though both groups manifest age-associated B cell dysfunction. PMID:28448963

  16. Developing legally defensible physiological employment standards for prominent physically demanding public safety occupations: a Canadian perspective.

    Science.gov (United States)

    Jamnik, V; Gumienak, R; Gledhill, N

    2013-10-01

    Canadian court decisions and human rights legislation impose strict legal criteria for developing applicant and incumbent physiological employment standards to qualify as a bona fide occupational requirement. These legal criteria compel researchers and employers to ensure that the standards are criterion-based and validly linked to the critical life threatening physically demanding tasks of the occupation, and this has led to the establishment of a systematic research process template to ensure this connection. Validation of job-related physiological employment standards is achieved using both construct and content procedures and reliability is established via test-retest procedures. The 1999 Supreme Court of Canada Meiorin Decision also obliges employers to demonstrate that it is impossible to accommodate an individual applicant or employee who is adversely impacted by lowering the physiological employment standards without imposing undue hardship on the employer. Recent evidence has demonstrated convincingly that familiarization opportunities, motivational feedback/coaching during test performance, and participation in a 6-week job-specific physical fitness training program can overcome the adverse impact of a physiological employment standards on a sub-group of participants, thereby providing "de facto" accommodation. In this article, the authors review the physiological employment standards for prominent Canadian physically demanding public safety occupations; police, correctional officers, nuclear emergency personnel, structural fire fighters, and wildland fire fighters, to illustrate the steps, challenges, and solutions involved in developing and implementing physiological employment standards designed to meet the requirements to qualify as a bona fide occupational requirement.

  17. Point-of-Sale Tobacco Advertising Remains Prominent in Mumbai, India.

    Science.gov (United States)

    Khariwala, Samir S; Garg, Apurva; Stepanov, Irina; Gupta, Prakash C; Ahluwalia, Jasjit S; Gota, Vikram; Chaturvedi, Pankaj

    2016-07-01

    In India, a 2003 law ("COPTA") banned tobacco advertising with the exception of "point of sale" and "on-pack" advertising. Given substantial evidence regarding the impact of point of sale advertising (PoS), we analyzed the prevalence of encountering such advertising in Mumbai, India. A survey was conducted of 199 current and recent former tobacco users recruited at the Tata Memorial Hospital (Mumbai). Enrollees were queried regarding their exposure to tobacco advertising in the last 30 days through multiple media sources. Descriptive epidemiologic techniques were used to characterize the data. Overall, 95% of participants were men and 5% were women (mean age=49 years). All were current tobacco users or quit using all forms of tobacco in the last 60 days. Participants' responses revealed that PoS tobacco advertising had been encountered in the last 30 days for cigarettes (61%), bidis (54%), and smokeless tobacco (59%). Other forms of tobacco advertising were virtually non-existent. PoS tobacco advertising remains prominent and highly visible to consumers in Mumbai, India, indicating corporate exploitation of a loophole in the COPTA legislation. Given the observed compliance with the currently imposed bans, revisions of COPTA to include all forms of tobacco promotion and advertising would be impactful.

  18. Paradoxical aging in HIV: immune senescence of B Cells is most prominent in young age.

    Science.gov (United States)

    Rinaldi, Stefano; Pallikkuth, Suresh; George, Varghese K; de Armas, Lesley R; Pahwa, Rajendra; Sanchez, Celeste M; Pallin, Maria Fernanda; Pan, Li; Cotugno, Nicola; Dickinson, Gordon; Rodriguez, Allan; Fischl, Margaret; Alcaide, Maria; Gonzalez, Louis; Palma, Paolo; Pahwa, Savita

    2017-04-01

    Combination antiretroviral therapies (cART)can lead to normal life expectancy in HIV-infected persons, and people aged >50 yrs represent the fastest growing HIV group. Although HIV and aging are independently associated with impaired humoral immunity, immune status in people aging with HIV is relatively unexplored. In this study influenza vaccination was used to probe age associated perturbations in the B cell compartment of HIV-negative "healthy controls" (HC) and virologically controlled HIV-infected participants on cART (HIV) (n=124), grouped by age as young (aged (40-59yrs) or old ( > 60 yrs). H1N1 antibody response at d21 post-vaccination correlated inversely with age in both HC and HIV. Immunophenotyping of cryopreserved PBMC demonstrated increased frequencies of double negative B cells and decreased plasmablasts in old compared to young HC. Remarkably, young HIV were different from young HC but similar to old HC in B cell phenotype, influenza specific spontaneous (d7) or memory (d21) antibody secreting cells. We conclude that B cell immune senescence is a prominent phenomenon in young HIV in comparison to young HC, but distinctions between old HIV and old HC are less evident though both groups manifest age-associated B cell dysfunction.

  19. Prominent Midlatitude Circulation Signature in High Asia's Surface Climate During Monsoon

    Science.gov (United States)

    Mölg, Thomas; Maussion, Fabien; Collier, Emily; Chiang, John C. H.; Scherer, Dieter

    2017-12-01

    High Asia has experienced strong environmental changes in recent decades, as evident in records of glaciers, lakes, tree rings, and vegetation. The multiscale understanding of the climatic drivers, however, is still incomplete. In particular, few systematic assessments have evaluated to what degree, if at all, the midlatitude westerly circulation modifies local surface climates in the reach of the Indian Summer Monsoon. This paper shows that a southward shift of the upper-tropospheric westerlies contributes significantly to climate variability in the core monsoon season (July-September) by two prominent dipole patterns at the surface: cooling in the west of High Asia contrasts with warming in the east, while moist anomalies in the east and northwest occur with drying along the southwestern margins. Circulation anomalies help to understand the dipoles and coincide with shifts in both the westerly wave train and the South Asian High, which imprint on air mass advection and local energy budgets. The relation of the variabilities to a well-established index of midlatitude climate dynamics allows future research on climate proxies to include a fresh hypothesis for the interpretation of environmental changes.

  20. N-acetyl-L-histidine, a Prominent Biomolecule in Brain and Eye of Poikilothermic Vertebrates.

    Science.gov (United States)

    Baslow, Morris H; Guilfoyle, David N

    2015-04-24

    N-acetyl-L-histidine (NAH) is a prominent biomolecule in brain, retina and lens of poikilothermic vertebrates. In fish lens, NAH exhibits an unusual compartmentalized metabolism. It is synthesized from L-histidine (His) and acetyl Co-enzyme A. However, NAH cannot be catabolized by lens cells. For its hydrolysis, NAH is exported to ocular fluid where a specific acylase cleaves His which is then actively taken up by lens and re-synthesized into NAH. This energy-dependent cycling suggested a pump mechanism operating at the lens/ocular fluid interface. Additional studies led to the hypothesis that NAH functioned as a molecular water pump (MWP) to maintain a highly dehydrated lens and avoid cataract formation. In this process, each NAH molecule released to ocular fluid down its gradient carries with it 33 molecules of bound water, effectively transporting the water against a water gradient. In ocular fluid the bound water is released for removal from the eye by the action of NAH acylase. In this paper, we demonstrate for the first time the identification of NAH in fish brain using proton magnetic resonance spectroscopy (MRS) and describe recent evidence supporting the NAH MWP hypothesis. Using MRS, we also document a phylogenetic transition in brain metabolism between poikilothermic and homeothermic vertebrates.

  1. Influence of the Fragmentation Process on the Eruptive Dynamics of Vulcanian Eruptions: an Experimental Approach

    Science.gov (United States)

    Alatorre-Ibarguengoitia, M. A.; Arciniega-Ceballos, A.; Dingwell, D. B.; Richard, D.; Scheu, B.; Kueppers, U.; Delgado-Granados, H.; Navarrete Montesinos, M.

    2009-12-01

    During volcanic eruptions, the ejection velocity of the gas-pyroclast mixture is one of the main parameters that control the behavior of the eruptive column near the vent. Together with other factors such as density of the mixture, temperature and vent geometry, it determines whether a buoyant plume can develop or if the column will collapse leading to a pyroclastic flow. Thus, an accurate description of the relationship between conduit pressure and ejection velocity is required for an adequate hazard analysis. In addition, ejection velocities obtained from field observations allow us to estimate pre-eruption conduit pressures. Theoretical and experimental studies to date have largely neglected the effects of the magmatic fragmentation on the dynamics of the gas-pyroclast mixture. The eruptive dynamics of Vulcanian eruptions has been investigated using the 1-D shock-tube theory, which consists of pressurized magma separated from the air by a diaphragm. After the rupture of the diaphragm, a shock wave propagates into the air and a rarefaction wave propagates into the magma. If the differential pressure is high enough, a fragmentation front develops and travels through the magma while the fragments are ejected. For this study, fragmentation, ejection and shock wave velocities were simultaneously measured for each fragmentation experiment performed on natural volcanic samples with diverse porosities and different applied pressures (5-25 MPa). To this end, we used a synchronized array of dynamic pressure transducers, laser beams and receivers, charged wires and piezo film sensors. Our results show that the fragmentation process plays an important role in the dynamics of the gas-particles mixture for the following reasons: 1) the energy consumed by fragmentation reduces the energy available to accelerate the gas-particle mixture; 2) the grain-size distribution produced during fragmentation controls the mechanical and thermal coupling between the gas phase and the

  2. Eruptive parameters and dynamics of the April 2015 sub-Plinian eruptions of Calbuco volcano (southern Chile)

    Science.gov (United States)

    Castruccio, Angelo; Clavero, Jorge; Segura, Andrea; Samaniego, Pablo; Roche, Olivier; Le Pennec, Jean-Luc; Droguett, Bárbara

    2016-09-01

    We conducted geological and petrological analyses of the tephra fallout and pyroclastic density current (PDC) products of the 22-23 April 2015 Calbuco eruptions. The eruptive cycle consisted of two sub-Plinian phases that generated > 15 km height columns and PDCs that travelled up to 6 km from the vent. The erupted volume is estimated at 0.38 km3 (non-DRE), with approximately 90% corresponding to tephra fall deposits and the other 10% to PDC deposits. The erupted products are basaltic-andesite, 54-55 wt.% SiO2, with minor amounts of andesite (58 wt.% SiO2). Despite the uniform composition of the products, there are at least four types of textures in juvenile clasts, with different degrees of vesicularity and types and content of crystals. We propose that the eruption triggering mechanism was either exsolution of volatiles due to crystallization, or a small intrusion into the base of the magma chamber, without significant magma mixing or with a magma compositionally similar to that of the residing magma. In either case the triggering mechanism generated convection and sufficient overpressure to promote the first eruptive phase. The start of the eruption decompressed the chamber, promoting intense vesiculation of the remaining magma and an increase in eruption rate towards the end of the eruption.

  3. Thallium as a tracer for preindustrial volcanic eruptions in an ice core record from Illimani, Bolivia.

    Science.gov (United States)

    Kellerhals, Thomas; Tobler, Leonhard; Brütsch, Sabina; Sigl, Michael; Wacker, Lukas; Gäggeler, Heinz W; Schwikowski, Margit

    2010-02-01

    Trace element records from glacier and ice sheet archives provide insights into biogeochemical cycles, atmospheric circulation changes, and anthropogenic pollution history. We present the first continuous high-resolution thallium (Tl) record, derived from an accurately dated ice core from tropical South America, and discuss Tl as a tracer for volcanic eruptions. We identify four prominent Tl peaks and propose that they represent signals from the massive explosive eruptions of the "unknown 1258" A.D. volcano, of Kuwae ( approximately 1450 A.D.), Tambora (1815 A.D.), and Krakatoa (1883 A.D.). The highly resolved record was obtained with an improved setup for the continuous analysis of trace elements in ice with inductively coupled plasma sector field mass spectrometry (ICP-SFMS). The new setup allowed for a stronger initial acidification of the meltwater and shorter tubing length, thereby reducing the risk of memory effects and losses of analytes to the capillary walls. With a comparison of the continuous method to the established conventional decontamination and analysis procedure for discrete samples, we demonstrate the accuracy of the continuous method for Tl analyses.

  4. Erythema Ab Igne in an Adolescent With Chronic Pain: An Alarming Cutaneous Eruption From Heat Exposure.

    Science.gov (United States)

    Gmuca, Sabrina; Yu, JiaDe; Weiss, Pamela F; Treat, James R; Sherry, David D

    2018-03-12

    Erythema ab igne (EAI) is a cutaneous finding caused by prolonged heat exposure and is characterized by a reticular, brownish-pigmented, often telangiectatic dermatosis. The eruption is reminiscent of livedo reticularis, which is typically seen in the setting of a number of rheumatologic conditions, most prominently vasculitis. Identification of key features distinguishing EAI from livedo reticularis can aid in the diagnosis of EAI and correct elucidation of the underlying etiology. Our patient presented with heating pad-induced EAI in the setting of chronic pain. Only 6 other pediatric cases of EAI associated with heat sources for chronic pain are reported (Acta Derm Venereol. 2014;94:365-367, J Pediatr. 2013;163:1789, Int J Eat Disord. 2013;46:381-383, Arch Dis Child. 2008;93:389, Arch Pediatr Adolesc Med. 2012;166:185-186, Br J Clin Pract. 1990;44:248-251). Our case highlights the need for awareness of this pathognomonic skin eruption in children with chronic pain conditions to help avoid an extensive workup for vasculitis.

  5. A Microfilament-Eruption Mechanism for Solar Spicules

    Science.gov (United States)

    Sterling, A. C.; Moore, R. L.

    2017-12-01

    Recent studies indicate that solar coronal jets result from eruption of small-scale filaments, or "minifilaments" (Sterling et al. 2015, Nature, 523, 437; Panesar et al. ApJL, 832L, 7). In many aspects, these coronal jets appear to be small-scale versions of long-recognized large-scale solar eruptions that are often accompanied by eruption of a large-scale filament and that produce solar flares and coronal mass ejections (CMEs). In coronal jets, a jet-base bright point (JBP) that is often observed to accompany the jet and that sits on the magnetic neutral line from which the minifilament erupts, corresponds to the solar flare of larger-scale eruptions that occurs at the neutral line from which the large-scale filament erupts. Large-scale eruptions are relatively uncommon ( 1/day) and occur with relatively large-scale erupting filaments ( 10^5 km long). Coronal jets are more common (> 100s/day), but occur from erupting minifilaments of smaller size ( 10^4 km long). It is known that solar spicules are much more frequent (many millions/day) than coronal jets. Just as coronal jets are small-scale versions of large-scale eruptions, here we suggest that solar spicules might in turn be small-scale versions of coronal jets; we postulate that the spicules are produced by eruptions of ``microfilaments'' of length comparable to the width of observed spicules ( 300 km). A plot of the estimated number of the three respective phenomena (flares/CMEs, coronal jets, and spicules) occurring on the Sun at a given time, against the average sizes of erupting filaments, minifilaments, and the putative microfilaments, results in a size distribution that can be fit with a power-law within the estimated uncertainties. The counterparts of the flares of large-scale eruptions and the JBPs of jets might be weak, pervasive, transient brightenings observed in Hinode/CaII images, and the production of spicules by microfilament eruptions might explain why spicules spin, as do coronal jets. The

  6. From Mush to Eruption in 1000 Years: Rapid Assembly of the Super-Sized Oruanui Magma Body

    Science.gov (United States)

    Allan, A. S.; Morgan, D. J.; Wilson, C. J.; Millet, M.

    2012-12-01

    The mush model is useful in explaining how large volumes of evolved silicic melt can be generated in and extracted from a crystal-rich source to form crystal-poor rhyolite magma bodies at shallow crustal levels. It is unclear, however, how processes of melt extraction and/or formation of the melt-dominant magma body might be reflected in the crystal record, and what physical and temporal constraints can be applied. Textural observations and in situ geochemical fingerprints in crystals from pumices of the ~25.4 ka Oruanui eruption (Taupo, New Zealand), offer new perspectives on the processes, physical conditions and timing of the melt extraction and accumulation. Almost all orthopyroxene (opx) and plagioclase (plag) cores have textures showing a period of disequilibrium (partial dissolution and/or resorption) followed by stable conditions (infilling of raddled cores; euhedral rim overgrowths). Trace element contents in amphibole (amph), which was stable and actively crystallizing in all but the most evolved parcels of Oruanui magma, complement textural evidence showing that Mn and Zn liberated by opx dissolution were preferentially sequestered in amph. Concentrations of these opx-loving elements show a prominent inflection when plotted against indices of melt evolution (e.g. Eu/Eu* in amph) marking a return to opx stability and subsequent crystallization. Plagioclase, the most abundant crystal phase, records a more complex history with significant inheritance, but textural and chemical evidence suggests that at least some of Oruanui plag crystals experienced the same departure from and return to stability as the opx. Amphibole trace element data are linked to in situ estimates of P-T-fO2 and melt H2O determined via the Ridolfi et al. (2010: Contrib Mineral Petrol 160, 45) thermobarometer. Textural and geochemical evidence combined with P-T-H2O model values indicate that three major Oruanui crystal phases (opx, amph, plag) record a significant decompression event

  7. Elastic energy release in great earthquakes and eruptions

    Directory of Open Access Journals (Sweden)

    Agust eGudmundsson

    2014-05-01

    Full Text Available The sizes of earthquakes are measured using well-defined, measurable quantities such as seismic moment and released (transformed elastic energy. No similar measures exist for the sizes of volcanic eruptions, making it difficult to compare the energies released in earthquakes and eruptions. Here I provide a new measure of the elastic energy (the potential mechanical energy associated with magma chamber rupture and contraction (shrinkage during an eruption. For earthquakes and eruptions, elastic energy derives from two sources: (1 the strain energy stored in the volcano/fault zone before rupture, and (2 the external applied load (force, pressure, stress, displacement on the volcano/fault zone. From thermodynamic considerations it follows that the elastic energy released or transformed (dU during an eruption is directly proportional to the excess pressure (pe in the magma chamber at the time of rupture multiplied by the volume decrease (-dVc of the chamber, so that . This formula can be used as a basis for a new eruption magnitude scale, based on elastic energy released, which can be related to the moment-magnitude scale for earthquakes. For very large eruptions (>100 km3, the volume of the feeder-dike is negligible, so that the decrease in chamber volume during an eruption corresponds roughly to the associated volume of erupted materials , so that the elastic energy is . Using a typical excess pressures of 5 MPa, it is shown that the largest known eruptions on Earth, such as the explosive La Garita Caldera eruption (27-28 million years ago and largest single (effusive Colombia River basalt lava flows (15-16 million years ago, both of which have estimated volumes of about 5000 km3, released elastic energy of the order of 10EJ. For comparison, the seismic moment of the largest earthquake ever recorded, the M9.5 1960 Chile earthquake, is estimated at 100 ZJ and the associated elastic energy release at 10EJ.

  8. Pattern and pace of dental eruption in Tarsius.

    Science.gov (United States)

    Guthrie, Emily H; Frost, Stephen R

    2011-07-01

    This article uses data on the dental eruption pattern and life history of Tarsius to test the utility of Schultz's rule. Schultz's rule claims a relationship between the relative pattern of eruption and the absolute pace of dental development and life history and may be useful in reconstructing life histories in extinct primates. Here, we document an unusual eruption pattern in Tarsius combining early eruption (relative to molars) of anterior replacement teeth (P2 and incisors) and relatively late eruption of the posterior replacement teeth (C, P3, and P4). This eruption pattern does not accurately predict the "slow" pace of life documented for Tarsius [Roberts: Int J Primatol 15 (1994) 1-28], nor aspects of life history directly associated with dental development as would be expected using Schultz's rule. In Tarsius, the anterior teeth and M1 erupt at an early age and therefore are not only fast in a relative sense but also fast in an absolute sense. This seems to be related to a developmental anomaly in the deciduous precursor teeth, which are essentially skipped. This decoupling among dental eruption pattern, dental eruption pace, and life history pace in Tarsius undermines the assumptions that life histories can accurately be described as "fast" or "slow" and that dental eruption pattern alone can be used to infer overall life history pace. The relatively and absolutely early eruption of the anterior dentition may be due to the utility of these front teeth in early food acquisition rather than with the pace of life history. Copyright © 2011 Wiley-Liss, Inc.

  9. The Novarupta-Katmai eruption of 1912 - largest eruption of the twentieth century; centennial perspectives

    Science.gov (United States)

    Hildreth, Wes; Fierstein, Judy

    2012-01-01

    The explosive outburst at Novarupta (Alaska) in June 1912 was the 20th century's most voluminous volcanic eruption. Marking its centennial, we illustrate and document the complex eruptive sequence, which was long misattributed to nearby Mount Katmai, and how its deposits have provided key insights about volcanic and magmatic processes. It was one of the few historical eruptions to produce a collapsed caldera, voluminous high-silica rhyolite, wide compositional zonation (51-78 percent SiO2), banded pumice, welded tuff, and an aerosol/dust veil that depressed global temperature measurably. It emplaced a series of ash flows that filled what became the Valley of Ten Thousand Smokes, sustaining high-temperature metal-transporting fumaroles for a decade. Three explosive episodes spanned ~60 hours, depositing ~17 km3 of fallout and 11±2 km3 of ignimbrite, together representing ~13.5 km3 of zoned magma. No observers were nearby and no aircraft were in Alaska, and so the eruption narrative was assembled from scattered villages and ship reports. Because volcanology was in its infancy and the early investigations (1915-23) were conducted under arduous expeditionary conditions, many provocative misapprehensions attended reports based on those studies. Fieldwork at Katmai was not resumed until 1953, but, since then, global advances in physical volcanology and chemical petrology have gone hand in hand with studies of the 1912 deposits, clarifying the sequence of events and processes and turning the eruption into one of the best studied in the world. To provide perspective on this century-long evolution, we describe the geologic and geographic setting of the eruption - in a remote, sparsely inhabited wilderness; we review the cultural and scientific contexts at the time of the eruption and early expeditions; and we compile a chronology of the many Katmai investigations since 1912. Products of the eruption are described in detail, including eight layers of regionwide fallout

  10. The eruption of Mount Pagan volcano, Mariana Islands, 15 May 1981

    Science.gov (United States)

    Banks, N.G.; Koyanagi, R.Y.; Sinton, J.M.; Honma, K.T.

    1984-01-01

    A major explosive eruption occurred 15 May 1981 at Mount Pagan Volcano, the larger of two historic eruptive centers on Pagan Island, Mariana Islands. The eruption was preceded by increased numbers of locally felt earthquakes beginning in late March or early April and by new ground cracks, new sublimates, and increased gas emissions. A swarm of felt earthquakes began at 0745h (local time = UCT+10 hours) 15 May, and at 0915 h, closely following a loud sonic boom, a strong plinian column issued from the volcano. The high-altitude ash cloud (at least 13.5 km) travelled south-southeast, but ash and scoria deposits were thickest (> 2 m) in the NW sector of the island because of the prevailing low-altitude southeasterly winds. The early activity of 15 May probably involved magmatic eruption along a fissure system oriented about N10??E. However, the eruption became hydromagmatic, possibly within minutes, and was largely restricted to three long-lived vents. The northernmost of these built a substantial new scoria-ash cinder cone. Flows and air-fall deposits, consisting almost entirely of juvenile material, exceeded 105 ?? 106 m3 in volume (75 ?? 106 m3 of magma) on land and at least 70-100 ?? 606 m3 at sea. An unknown volume was carried away by stratospheric winds. Lithic blocks and juvenile bombs as large as 1 m in diameter were thrown more than 2 km from the summit, and evidence for base-surge was observed in restricted corridors as low as 200 m elevation on the north and south slopes of the volcano. Neither of these events resulted in serious injuries to the 54 residents of the island, nor did the eruption produce serious chemical hazards in their water supply. Weak eruptions occurred during the ensuing month, and some of these were monitored by ground observations, seismic monitoring, and deformation studies. Precursory seismicity and possibly deformation occurred with some of the observed eruptions. More vigorous eruptions were reported by visiting residents in late

  11. Recent Eruptive History of the Tatun Volcanic Group, Northern Taiwan: Hazard-related Issues

    Science.gov (United States)

    Belousov, A.; Belousova, M.; Chen, C.

    2009-12-01

    show evidence of water/magma interaction: poor sorting, wide span of vesicularity of juvenile material, abundant xenoliths of country rocks, associated base surges, as well as ballistics of bread-crust and cauliflower type. Deposits of block-and-ash pyroclastic flows are lithic-rich and probably were formed mostly by collapses of growing domes and advancing lava flows (Merapi type). This study presents the first radiocarbon dates of various volcanoclastic deposits of the TVG, which indicate that Cising, Siaoguanyin, and possibly Huangzuei volcanoes had magmatic eruptions in the period 13,000 - 23,000 years ago. In addition, Mt. Cising had a phreatic eruption 6000 years ago. Our data have shown that TVG volcanoes should be considered as active. The results form the basis for reassessment of volcanic hazards of the area. Reference: Stevenson, R.J., Hodder, A.P.W., Briggs, R.M. (1994) Rheological estimated of rhyolite lava flows from the Okataina Volcanic Centre, New Zealand. New Zealand Journal of Geology and Geophysics, v.37: 211-221

  12. Fixed Drug Eruption due to Achiote Dye

    Science.gov (United States)

    Tattersall, Ian; Reddy, Bobby Y.

    2016-01-01

    Fixed drug eruption (FDE) is a localized type IV sensitivity reaction to a systemically introduced allergen. It usually occurs as a result of new medication, making identification and avoidance of the trigger medication straightforward; however, in a rare subset of cases no pharmacological source is identified. In such cases, the causative agent is often a food or food additive. In this report we describe a case of a FDE in a 12-year-old girl recently immigrated to the United States from Ecuador who had no medication exposure over the course of her illness. Through an exhaustive patient history and literature review, we were able to hypothesize that her presentation was caused by a dietary change of the natural achiote dye used in the preparation of yellow rice to a locally available commercial dye mix containing tartrazine, or Yellow 5, which has previously been implicated in both systemic hypersensitivity reactions and specifically in FDE. This report adds to the small body of available literature on non-pharmacological fixed hypersensitivity eruptions and illustrates an effective approach to the management of such a presentation when history is not immediately revealing. PMID:26933409

  13. Fixed Drug Eruption due to Achiote Dye

    Directory of Open Access Journals (Sweden)

    Ian Tattersall

    2016-01-01

    Full Text Available Fixed drug eruption (FDE is a localized type IV sensitivity reaction to a systemically introduced allergen. It usually occurs as a result of new medication, making identification and avoidance of the trigger medication straightforward; however, in a rare subset of cases no pharmacological source is identified. In such cases, the causative agent is often a food or food additive. In this report we describe a case of a FDE in a 12-year-old girl recently immigrated to the United States from Ecuador who had no medication exposure over the course of her illness. Through an exhaustive patient history and literature review, we were able to hypothesize that her presentation was caused by a dietary change of the natural achiote dye used in the preparation of yellow rice to a locally available commercial dye mix containing tartrazine, or Yellow 5, which has previously been implicated in both systemic hypersensitivity reactions and specifically in FDE. This report adds to the small body of available literature on non-pharmacological fixed hypersensitivity eruptions and illustrates an effective approach to the management of such a presentation when history is not immediately revealing.

  14. Sulfur and oxygen isotopic systematics of the 1982 eruptions of El Chichón Volcano, Chiapas, Mexico

    Science.gov (United States)

    Rye, R.O.; Luhr, J.F.; Wasserman, M.D.

    1984-01-01

    Thermometers based on sulfur and oxygen isotopic compositions of anhydrite, pyrrhotite, titanomagnetite, and plagioclase crystals from fresh pumices of the 1982 eruptions of El Chichón Volcano indicate a pre-eruption temperature of 810 ± 40°C, confirming textural evidence that the anhydrite precipitated directly from the melt. The isotopic composition of sulfate leached from fresh ashfall samples shows it to be a mixture of anhydrite microphenocrysts and adsorbed sulfate derived from oxidized sulfur (SO2) in the eruption plume. The leachate data show no evidence for rapid oxidation of significant amounts of H2S in the eruption cloud even though the fugacity ratio of H2S/SO2 in the gas phase of the magma was >400. This may indicate kinetic inhibition of H2S to SO2 conversion in the eruption cloud. Prior to eruption, the magma contained an estimated 2.6 wt. % sulfur (as SO3). The estimated δ 34S of the bulk magma is 5.8‰. Such a high value may reflect assimilation of 34S-enriched evaporites or the prior loss of 34S-depleted H2S to a fluid or gas phase during formation of a small prophyry-type hydrothermal system or ore deposit. In either case, the original magma must have been very sulfur rich. It is likely that the initial high sulfur content of the magma and at least some of its 34S enrichment reflects involvement of subducted volcanogenic massive sulfides deposits during Benioff-zone partial melting. Isotopic data on mineralized, accidental lithic fragments support the possible development of a porphyry-type system at El Chichón.

  15. Prominence plasma and magnetic field structure - A coordinated observation with IRIS, Hinode and THEMIS

    Science.gov (United States)

    Schmieder, Brigitte; Labrosse, Nicolas; Levens, Peter; Lopez Ariste, Arturo

    2016-07-01

    During an international campaign in 2014, utilising both space-based (IRIS and Hinode) and ground-based (THEMIS) instruments, we focused on observing prominences. We compare IRIS observations with those of Hinode (EIS and SOT) in order to build a more complete picture of the prominence structure for a quiescent prominence observed on 15 July 2014, identified to have tornado-like structure. THEMIS provides valuable information on the orientation and strength of the internal magnetic field. Here we find there is almost ubiquitously horizontal field with respect to the local limb, with possibly a turbulent component. The Mg II lines form the majority of our IRIS analysis, with a mixture of reversed and non-reversed profiles present in the prominence spectra. Comparing the differences between the Mg II data from IRIS and the Ca II images from Hinode/SOT provides an intriguing insight into the prominence legs in these channels. We present plasma diagnostics from IRIS, with line of sight velocities of around 10 km/s in either direction along the magnetic loops of material in the front of the prominence, and line widths comparable to those found for prominences by previous authors (e.g. Schmieder et al. 2014). We also take a look into the lines formed at higher, coronal plasma temperatures, as seen by Hinode/EIS, to compare plasma structures at a full range of temperatures.

  16. TORNADO-LIKE EVOLUTION OF A KINK-UNSTABLE SOLAR PROMINENCE

    International Nuclear Information System (INIS)

    Wang, Wensi; Liu, Rui; Wang, Yuming

    2017-01-01

    We report on the tornado-like evolution of a quiescent prominence on 2014 November 1. The eastern section of the prominence first rose slowly, transforming into an arch-shaped structure as high as ∼150 Mm above the limb; the arch then writhed moderately in a left-handed sense, while the original dark prominence material emitted in the Fe ix 171 Å passband, and a braided structure appeared at the eastern edge of the warped arch. The unraveling of the braided structure was associated with a transient brightening in the EUV and apparently contributed to the formation of a curtain-like structure (CLS). The CLS consisted of myriad thread-like loops rotating counterclockwise about the vertical if viewed from above. Heated prominence material was observed to slide along these loops and land outside the filament channel. The tornado eventually disintegrated and the remaining material flew along a left-handed helical path constituting approximately a full turn, as corroborated through stereoscopic reconstruction, into the cavity of the stable, western section of the prominence. We suggest that the tornado-like evolution of the prominence was governed by the helical kink instability, and that the CLS formed through magnetic reconnections between the prominence field and the overlying coronal field.

  17. The submarine volcano eruption off El Hierro Island: effects on the scattering migrant biota and the evolution of the pelagic communities.

    Science.gov (United States)

    Ariza, Alejandro; Kaartvedt, Stein; Røstad, Anders; Garijo, Juan Carlos; Arístegui, Javier; Fraile-Nuez, Eugenio; Hernández-León, Santiago

    2014-01-01

    The submarine volcano eruption off El Hierro Island (Canary Islands) on 10 October 2011 promoted dramatic perturbation of the water column leading to changes in the distribution of pelagic fauna. To study the response of the scattering biota, we combined acoustic data with hydrographic profiles and concurrent sea surface turbidity indexes from satellite imagery. We also monitored changes in the plankton and nekton communities through the eruptive and post-eruptive phases. Decrease of oxygen, acidification, rising temperature and deposition of chemicals in shallow waters resulted in a reduction of epipelagic stocks and a disruption of diel vertical migration (nocturnal ascent) of mesopelagic organisms. Furthermore, decreased light levels at depth caused by extinction in the volcanic plume resulted in a significant shallowing of the deep acoustic scattering layer. Once the eruption ceased, the distribution and abundances of the pelagic biota returned to baseline levels. There was no evidence of a volcano-induced bloom in the plankton community.

  18. The submarine volcano eruption off El Hierro Island: Effects on the scattering migrant biota and the evolution of the pelagic communities

    KAUST Repository

    Ariza, Alejandro

    2014-07-21

    The submarine volcano eruption off El Hierro Island (Canary Islands) on 10 October 2011 promoted dramatic perturbation of the water column leading to changes in the distribution of pelagic fauna. To study the response of the scattering biota, we combined acoustic data with hydrographic profiles and concurrent sea surface turbidity indexes from satellite imagery. We also monitored changes in the plankton and nekton communities through the eruptive and post-eruptive phases. Decrease of oxygen, acidification, rising temperature and deposition of chemicals in shallow waters resulted in a reduction of epipelagic stocks and a disruption of diel vertical migration (nocturnal ascent) of mesopelagic organisms. Furthermore, decreased light levels at depth caused by extinction in the volcanic plume resulted in a significant shallowing of the deep acoustic scattering layer. Once the eruption ceased, the distribution and abundances of the pelagic biota returned to baseline levels. There was no evidence of a volcano-induced bloom in the plankton community. © 2014 Ariza et al.

  19. The submarine volcano eruption off El Hierro Island: effects on the scattering migrant biota and the evolution of the pelagic communities.

    Directory of Open Access Journals (Sweden)

    Alejandro Ariza

    Full Text Available The submarine volcano eruption off El Hierro Island (Canary Islands on 10 October 2011 promoted dramatic perturbation of the water column leading to changes in the distribution of pelagic fauna. To study the response of the scattering biota, we combined acoustic data with hydrographic profiles and concurrent sea surface turbidity indexes from satellite imagery. We also monitored changes in the plankton and nekton communities through the eruptive and post-eruptive phases. Decrease of oxygen, acidification, rising temperature and deposition of chemicals in shallow waters resulted in a reduction of epipelagic stocks and a disruption of diel vertical migration (nocturnal ascent of mesopelagic organisms. Furthermore, decreased light levels at depth caused by extinction in the volcanic plume resulted in a significant shallowing of the deep acoustic scattering layer. Once the eruption ceased, the distribution and abundances of the pelagic biota returned to baseline levels. There was no evidence of a volcano-induced bloom in the plankton community.

  20. A case of eruptive collagenoma localized on the neck and shoulders.

    Science.gov (United States)

    Amaya, Misato; Okubo, Yukari; Koga, Michiyuki

    2002-02-01

    A 78-year-old woman, who had first noticed asymptomatic eruptions on her neck and shoulders eight years earlier, presented with papules and nodules 2 to 20 mm in diameter that had a normal to white hue and were flatly elevated. These lesions were scattered and multiple, some forming confluent plaques. Histopathologically, the epidermis was slightly atrophied, and collagen fibers in the dermis were coarse and proliferated. In addition, the number of elastic fibers was slightly decreased. No complications were evident. Based on these findings, the patient was given a diagnosis of mild eruptive collagenoma, a type of connective tissue nevus according to the classification of Uitto. This case is unique in that onset was at an advanced age and that distribution was localized on the neck and shoulders.

  1. Studies of the chronological course of wisdom tooth eruption in a German population.

    Science.gov (United States)

    Olze, A; Peschke, C; Schulz, R; Schmeling, A

    2008-10-01

    Forensic age estimation in living subjects has gained increasing significance in recent years. In dental age estimation, tooth eruption is a parameter of developmental morphology that can be analyzed by either clinical examination or by evaluation of dental X-rays. In the present study, we determined the stage of wisdom tooth eruption in 144 male and 522 female German subjects aged 12-26 years based on radiological evidence from 666 conventional orthopantomograms. The results presented here provide useful data on the age of alveolar, gingival, and complete emergence of the third molars in the occlusal plane that can be utilized for the forensic estimation of the minimum and most probable ages of individuals under investigation.

  2. Studies of the chronological course of wisdom tooth eruption in a Japanese population.

    Science.gov (United States)

    Olze, A; Ishikawa, T; Zhu, B L; Schulz, R; Heinecke, A; Maeda, H; Schmeling, A

    2008-01-30

    The importance of forensic age estimation in living subjects has grown over the last few years. In dental age estimation, tooth eruption is a parameter of developmental morphology that can be analyzed by either clinical examination or by evaluation of dental X-rays. In the present study, we determined the stage of wisdom tooth eruption in 549 male and 751 female Japanese subjects aged 14-26 years based on radiological evidence from 1300 conventional orthopantomograms. The results presented here provide useful data on the age of alveolar, gingival, and complete emergence of the third molars in the occlusal plane that can be utilized for forensic estimation of the minimum and most probable ages of investigated persons.

  3. Triggering of the largest Deccan eruptions by the Chicxulub impact

    NARCIS (Netherlands)

    Richards, M.A.; Alvarez, W.; Self, S.; Karlstrom, L.; Renne, P.R.; Manga, M.; Sprain, C.J.; Smit, J.; Vanderkluysen, L.; Gibson, S.A.

    2015-01-01

    New constraints on the timing of the Cretaceous- Paleogene mass extinction and the Chicxulub impact, together with a particularly voluminous and apparently brief eruptive pulse toward the end of the "main-stage" eruptions of the Deccan continental flood basalt province suggest that these three

  4. A great volcanic eruption around AD 1300 recorded in lacustrine ...

    Indian Academy of Sciences (India)

    The Sr and Nd isotope compositions at 61 cm are in excellent agreement with those in volcanic materials, but they are significantly different from those in terrigenous dust, implying a possible material input from historical volcanic eruptions in the lacustrine sediment. DY6. The documented great Samalas volcanic eruption at ...

  5. Erupting complex odontoma: Report of a rare case

    Directory of Open Access Journals (Sweden)

    Pinakapani Ramakrishna

    2014-01-01

    Full Text Available Odontomas are the most frequent hamartomatous lesions involving the oral cavity. The complex variant is an agglomerate of all dental tissues characterized by abnormal morphodifferentiation despite normal histodifferentiation. These are usually asymptomatic and are frequently associated with eruption disturbances. We report an unusual case of erupting complex odontoma associated with an impacted maxillary second molar.

  6. A Tectonic Implication Of The Eruption Of Pyroclastics In Uturu ...

    African Journals Online (AJOL)

    Exposures of pyroclastics within flatland in Uturu, east of Okigwe, were studied with a view to determining the implication of the eruption that emplaced the pyroclastics on the tectonic evolution of the Lower Benue Trough. Field expressions show that the pyroclastics erupted parallel to the axial plane of the Abakiliki ...

  7. Effects of scoria-cone eruptions upon nearby human communities

    Science.gov (United States)

    Ort, M.H.; Elson, M.D.; Anderson, K.C.; Duffield, W.A.; Hooten, J.A.; Champion, D.E.; Waring, G.

    2008-01-01

    Scoria-cone eruptions are typically low in volume and explosivity compared with eruptions from stratovolcanoes, but they can affect local populations profoundly. Scoria-cone eruption effects vary dramatically due to eruption style, tephra blanket extent, climate, types of land use, the culture and complexity of the affected group, and resulting governmental action. A comparison of a historic eruption (Pari??cutin, Me??xico) with prehistoric eruptions (herein we primarily focus on Sunset Crater in northern Arizona, USA) elucidates the controls on and effects of these variables. Long-term effects of lava flows extend little beyond the flow edges. These flows, however, can be used for defensive purposes, providing refuges from invasion for those who know them well. In arid lands, tephra blankets serve as mulches, decreasing runoff and evaporation, increasing infiltration, and regulating soil temperature. Management and retention of these scoria mulches, which can open new areas for agriculture, become a priority for farming communities. In humid areas, though, the tephra blanket may impede plant growth and increase erosion. Cultural responses to eruptions vary, from cultural collapse, through fragmentation of society, dramatic changes, and development of new technologies, to little apparent change. Eruptions may also be viewed as retribution for poor behavior, and attempts are made to mollify angry gods. ?? 2008 Geological Society of America.

  8. Interdisciplinary studies of eruption at Chaiten Volcano, Chile

    Science.gov (United States)

    John S. Pallister; Jon J. Major; Thomas C. Pierson; Richard P. Hoblitt; Jacob B. Lowenstern; John C. Eichelberger; Lara. Luis; Hugo Moreno; Jorge Munoz; Jonathan M. Castro; Andres Iroume; Andrea Andreoli; Julia Jones; Fred Swanson; Charlie Crisafulli

    2010-01-01

    There was keen interest within the volcanology community when the first large eruption of high-silica rhyolite since that of Alaska's Novarupta volcano in 1912 began on 1 May 2008 at Chaiten volcano, southern Chile, a 3-kilometer-diameter caldera volcano with a prehistoric record of rhyolite eruptions. Vigorous explosions occurred through 8 May 2008, after which...

  9. Accelerated tooth eruption in children with diabetes mellitus.

    Science.gov (United States)

    Lal, Shantanu; Cheng, Bin; Kaplan, Selma; Softness, Barney; Greenberg, Ellen; Goland, Robin S; Lalla, Evanthia; Lamster, Ira B

    2008-05-01

    The objective of this study was to evaluate tooth eruption in 6- to 14-year-old children with diabetes mellitus. Tooth eruption status was assessed for 270 children with diabetes and 320 control children without diabetes. Data on important diabetes-related variables were collected. Analyses were performed using logistic regression models. Children with diabetes exhibited accelerated tooth eruption in the late mixed dentition period (10-14 years of age) compared to healthy children. For both case patients and control subjects the odds of a tooth being in an advanced eruptive stage were significantly higher among girls than boys. There was also a trend associating gingival inflammation with expedited tooth eruption in both groups. No association was found between the odds of a tooth being in an advanced stage of eruption and hemoglobin A(1c) or duration of diabetes. Patients with higher body mass index percentile demonstrated statistically higher odds for accelerated tooth eruption, but the association was not clinically significant. Children with diabetes exhibit accelerated tooth eruption. Future studies need to ascertain the role of such aberrations in dental development and complications such as malocclusion, impaired oral hygiene, and periodontal disease. The standards of care for children with diabetes should include screening and referral programs aimed at oral health promotion and disease prevention.

  10. Does fluoride in drinking water delay tooth eruption?

    Science.gov (United States)

    Jolaoso, Ismail Adeyemi; Kumar, Jayanth; Moss, Mark E

    2014-01-01

    The objectives of this study are to determine the effect of fluoride exposure on permanent tooth eruption patterns as well as to understand its effect on caries attack rate by accounting for the number of erupted tooth surfaces. We analyzed data from the 1986-1987 National Survey of Oral Health of US Schoolchildren to determine the mean number of erupted permanent teeth and permanent first molars according to fluoride level in drinking water. The analysis included 13,348 children aged 5-17 years with a history of single residence. We also estimated the attack rate (decayed, missing, and filled surfaces/surfaces at risk) for fluoride deficient, suboptimal, and optimally fluoridated areas adjusting for covariates. Multivariable statistical analyses were performed to control for potential confounders. By age 7, almost all permanent first molars had erupted. The adjusted mean number of erupted permanent first molars per child were 3.81, 3.67, and 3.92 in areas with erupted teeth. Exposure to fluoride in drinking water did not delay the eruption of permanent teeth. The observed difference in dental caries experience among children exposed to different fluoride levels could not be explained by the timing of eruption of permanent teeth. © 2014 American Association of Public Health Dentistry.

  11. Eruption of primary Incisors: prevalence of sequence reversal and ...

    African Journals Online (AJOL)

    Result: Nine (3.1 %) out of the 290 children assessed erupted the maxillary Incisors ahead of the mandibular counterparts and their mothers allowed the teeth to erupt normally. One hundred and fifty-seven (54.1 %) of the mothers agreed that the tooth should be allowed to grow normally as part of the series of the primary ...

  12. Requirement of alveolar bone formation for eruption of rat molars.

    Science.gov (United States)

    Wise, Gary E; He, Hongzhi; Gutierrez, Dina L; Ring, Sherry; Yao, Shaomian

    2011-10-01

    Tooth eruption is a localized event that requires a dental follicle (DF) to regulate the resorption of alveolar bone to form an eruption pathway. During the intra-osseous phase of eruption, the tooth moves through this pathway. The mechanism or motive force that propels the tooth through this pathway is controversial but many studies have shown that alveolar bone growth at the base of the crypt occurs during eruption. To determine if this bone growth (osteogenesis) was causal, experiments were designed in which the expression of an osteogenic gene in the DF, bone morphogenetic protein-6 (Bmp6), was inhibited by injection of the first mandibular molar of the rat with a small interfering RNA (siRNA) targeted against Bmp6. The injection was followed by electroporation to promote uptake of the siRNA. In 45 first molars injected, eruption was either delayed or completely inhibited (seven molars). In the impacted molars, an eruption pathway formed but bone growth at the base of the crypt was greatly reduced compared with the erupted first-molar controls. These studies show that alveolar bone growth at the base of the crypt is required for tooth eruption and that Bmp6 may be essential for promoting this growth. © 2011 Eur J Oral Sci.

  13. Large eruption complex odontome in a Saudi patient

    OpenAIRE

    Ahmed, Khalid A.

    2015-01-01

    Odontomas are odontogenic tumors formed of various dental tissues.They are classified into: central odontomas that are common, eruption odontomas that are rare with only 23 cases reported to date, and peripheral odontomas that are also rare. We present a case of a large complex eruption odontome in a 24-year-old Saudi male.

  14. Diffuse Papular Eruption of the Face and Eyelids.

    Science.gov (United States)

    Frisch, Stephanie; Kozel, Jessica; Jensen, Sarah; Vidal, Claudia I

    2017-01-01

    A 68-year-old Caucasian woman presented with a 1-month history of a facial and neck eruption (Figure 1A). Her face was covered with 3-mm monomorphic, pink, shiny, papules and rare pustules on an erythematous background. The eruption extended down the neck, her conjunctivae were injected, and her lid margins were inflamed. She had no history of rosacea.

  15. Motions in Prominence Barbs as observed by Hinode/SOT and IRIS

    Science.gov (United States)

    Kucera, Therese A.; Ofman, Leon; Tarbell, Theodore D.

    2016-05-01

    We discuss observations of prominence barb dynamics as observed by Hinode/SOT and IRIS. Prominence barbs extend outwards to the side of the main prominence spine and downwards towards the chromosphere. Their properties, including the structure of their magnetic field and the nature of the motions observed in them are a subject of current debate. We use a combination of high cadence, high resolution imaging, H-alpha Doppler, and Mg II line profile data to analyze and understand waves and flows in barbs and discuss their ramifications in terms of a model of the barb magnetic field as collection of dipped field lines.

  16. Multi-decadal satellite measurements of passive and eruptive volcanic SO2 emissions

    Science.gov (United States)

    Carn, Simon; Yang, Kai; Krotkov, Nickolay; Prata, Fred; Telling, Jennifer

    2015-04-01

    strongest volcanic SO2 sources between 2004 and 2015. OMI measurements are most sensitive to SO2 emission rates on the order of ~1000 tons/day or more, and thus the satellite data provide new constraints on the location and persistence of major volcanic SO2 sources. We find that OMI has detected non-eruptive SO2 emissions from at least ~60 volcanoes since 2004. Results of our analysis reveal the emergence of several major tropospheric SO2 sources that are not prominent in existing inventories (Ambrym, Nyiragongo, Turrialba, Ubinas), the persistence of some well-known sources (Etna, Kilauea) and a possible decline in emissions at others (e.g., Lascar). The OMI measurements provide particularly valuable information in regions lacking regular ground-based monitoring such as Indonesia, Melanesia and Kamchatka. We describe how the OMI measurements of SO2 total column, and their probability density function, can be used to infer SO2 emission rates for compatibility with existing emissions data and assimilation into chemical transport models. The satellite-derived SO2 emission rates are in good agreement with ground-based measurements from frequently monitored volcanoes (e.g., from the NOVAC network), but differ for other volcanoes. We conclude that some ground-based SO2 measurements may be biased high if collected during periods of elevated unrest, and hence may not be representative of long-term average emissions.

  17. Drawing the Curtain on Enceladus' South-Polar Eruptions

    Science.gov (United States)

    Spitale, Joseph N.; Hurford, Terry A.; Rhoden, Alyssa R.; Berkson, Emily E.; Platts, Symeon S.

    2015-11-01

    For a comprehensive description of Enceladus' south-polar eruptions observed at high resolution, they must be represented as broad curtains rather than discrete jets. Meanders in the fractures from which the curtains of material erupt give rise to optical illusions that look like discrete jets, even along fractures with no local variations in eruptive activity, implying that many features previously identified as "jets" are in fact phantoms. By comparing Cassini images with model curtain eruptions, we are able to obtain maps of eruptive activity that are not biased by the presence of those phantom jets. The average of our activity maps over all times agrees well with thermal maps produced by Cassini CIRS. We can best explain the observed curtains by assuming spreading angles with altitude of up to 14° and zenith angles of up to 8°, for curtains observed in geometries that are sensitive to those quantities.

  18. Probability of large explosive volcanic eruptions in the Cascades

    Science.gov (United States)

    Nathenson, M.; Clynne, M. A.

    2011-12-01

    Estimating the probability of large explosive eruptions in the Cascades is problematic because they occur relatively infrequently. Although some volcanic centers have been more likely to have large eruptions than others, the calculation of the probability of large eruptions for individual volcanic centers is inappropriate. A center that has had a large eruption in the past will not necessarily have a large eruption in the future, and the occurrence for individual volcanic centers is too infrequent to have much confidence in a probability estimate. The sources of some large eruptions are ambiguous (e.g. Shevlin Park Tuff, Oregon) or unknown (Dibekulewe ash), but because the effects of large eruptions are quite widespread, the precise location of the source is less important in terms of hazards. Thus, we focus on the calculation of probability of large eruptions for the Cascade arc as a whole. To estimate the probability, we have chosen a time period for documenting eruptions of 1.15 Ma (the age of the eruption of Kulshan caldera) as a balance between the likelihood of there being good information but with a long enough time period to get a reasonable number of occurrences. We have compiled data from the literature on eruptions larger than 5 km3 in erupted volume to exclude the relatively frequent eruptions ~1-2 km3. The largest eruptions are clearly or likely to have been associated with caldera formation. For erupted volumes greater than 5 km3, 19 events have occurred in the last 1.15 Ma. A plot of event number versus age shows a high rate of occurrence since 13.5 ka and a much lower rate before then. Most of the events since 13.5 ka are 5-10 km3. Events 10 km3 and larger have occurred at a reasonably constant rate since 630 ka. The difference between the two data sets is probably the poor preservation of deposits for events between 5 and 10 km3 that occurred prior to the ending of the glaciation at about 15 ka. Before 630 ka, the only eruption > 10 km3 is Kulshan

  19. Darwin's triggering mechanism of volcano eruptions

    Science.gov (United States)

    Galiev, Shamil

    2010-05-01

    Charles Darwin wrote that ‘… the elevation of many hundred square miles of territory near Concepcion is part of the same phenomenon, with that splashing up, if I may so call it, of volcanic matter through the orifices in the Cordillera at the moment of the shock;…' and ‘…a power, I may remark, which acts in paroxysmal upheavals like that of Concepcion, and in great volcanic eruptions,…'. Darwin reports that ‘…several of the great chimneys in the Cordillera of central Chile commenced a fresh period of activity ….' In particular, Darwin reported on four-simultaneous large eruptions from the following volcanoes: Robinson Crusoe, Minchinmavida, Cerro Yanteles and Peteroa (we cite the Darwin's sentences following his The Voyage of the Beagle and researchspace. auckland. ac. nz/handle/2292/4474). Let us consider these eruptions taking into account the volcano shape and the conduit. Three of the volcanoes (Minchinmavida (2404 m), Cerro Yanteles (2050 m), and Peteroa (3603 m)) are stratovolcanos and are formed of symmetrical cones with steep sides. Robinson Crusoe (922 m) is a shield volcano and is formed of a cone with gently sloping sides. They are not very active. We may surmise, that their vents had a sealing plug (vent fill) in 1835. All these volcanoes are conical. These common features are important for Darwin's triggering model, which is discussed below. The vent fill material, usually, has high level of porosity and a very low tensile strength and can easily be fragmented by tension waves. The action of a severe earthquake on the volcano base may be compared with a nuclear blast explosion of the base. It is known, that after a underground nuclear explosion the vertical motion and the surface fractures in a tope of mountains were observed. The same is related to the propagation of waves in conical elements. After the explosive load of the base. the tip may break and fly off at high velocity. Analogous phenomenon may be generated as a result of a

  20. Remote Sensing and GIS as Tools for Identifying Risk for Phreatomagmatic Eruptions in the Bishoftu Volcanic Field, Ethiopia

    Science.gov (United States)

    Pennington, H. G.; Graettinger, A.

    2017-12-01

    Bishoftu is a fast-growing town in the Oromia region of Ethiopia, located 47 km southeast of the nation's capital, Addis Ababa. It is situated atop a monogenetic basaltic volcanic field, called the Bishoftu Volcanic Field (BVF), which is composed of maar craters, scoria cones, lava flows, and rhyolite domes. Although not well dated, the morphology and archeological evidence have been used to infer a Holocene age, indicating that the community is exposed to continued volcanic risk. The presence of phreatomagmatic constructs in particular indicates that the hazards are not only vent-localized, but may have far reaching impacts. Hazard mapping is an essential tool for evaluating and communicating risks. This study presents the results of GIS analyses of proximal and distal syn-eruptive hazards associated with phreatomagmatic eruptions in the BVF. A digitized infrastructure map based on a SPOT 6 satellite image is used to identify the areas at risk from eruption scenarios. Parameters such as wind direction, vent location, and explosion energy are varied for hazard simulations to quantify the area impacted by different eruption scenarios. Proximal syn-eruptive hazards include tephra fall, base pyroclastic surges, and ballistic bombs. Distal hazards include predominantly ash fall. Eruption scenarios are simulated using Eject and Plumeria models as well as similar case studies from other urban volcanic fields. Within 5 km of the volcanic field center, more than 30 km2 of residential and commercial/industrial infrastructure will be damaged by proximal syn-eruptive hazards, in addition to 34 km2 of agricultural land, 291 km of roads, more than 10 km of railway, an airport, and two health centers. Within 100 km of the volcanic field center, ash fall will affect 3946 km2 of agricultural land, 179 km2 of residential land, and 28 km2 of commercial/industrial land. Approximately 2700 km of roads and railways, 553 km of waterways, an airport, and 14 health centers are located

  1. What We Can Learn from the Next Large Volcanic Eruption

    Science.gov (United States)

    Robock, A.

    2015-12-01

    The April 1982 eruption of El Chichón in México stimulated interest in the climate response to volcanic eruptions and produced very useful observations and modeling studies. The last large volcanic eruption, the June 15, 1991 eruption of Mt. Pinatubo in the Philippines, was the best observed eruption ever, and serves as a canonical example for studies of aerosol production and transport, climate response, and deposition on ice sheets. However, many aspects of both eruptions were poorly observed, climate model simulations of the response are imperfect, and new scientific issues, such as stratospheric sulfate geoengineering, raise new scientific questions that could be answered by better observations of the next large volcanic eruption. In this talk I will summarize what we know and do not know about large volcanic eruptions, and discuss new questions that can be addressed by being prepared for the next large eruption. These include: How and how fast will SO2 convert to sulfate aerosols? How will the aerosols grow? What will be the size distribution of the resulting sulfate aerosol particles? How will the aerosols be transported throughout the stratosphere? How much fine ash gets to the stratosphere, how long does it stay there, and what are its radiative and chemical impacts? How will temperatures change in the stratosphere as a result of the aerosol interactions with shortwave (particularly near IR) and longwave radiation? Are there large stratospheric water vapor changes associated with stratospheric aerosols? Is there an initial injection of water from the eruption? Is there ozone depletion from heterogeneous reactions on the stratospheric aerosols? As the aerosols leave the stratosphere, and as the aerosols affect the upper troposphere temperature and circulation, are there interactions with cirrus and other clouds?

  2. Estimating rates of decompression from textures of erupted ash particles produced by 1999-2006 eruptions of Tungurahua volcano, Ecuador

    Science.gov (United States)

    Wright, Heather M.N.; Cashman, Katharine V.; Mothes, Patricia A.; Hall, Minard L.; Ruiz, Andrés Gorki; Le Pennec, Jean-Luc

    2012-01-01

    Persistent low- to moderate-level eruptive activity of andesitic volcanoes is difficult to monitor because small changes in magma supply rates may cause abrupt transitions in eruptive style. As direct measurement of magma supply is not possible, robust techniques for indirect measurements must be developed. Here we demonstrate that crystal textures of ash particles from 1999 to 2006 Vulcanian and Strombolian eruptions of Tungurahua volcano, Ecuador, provide quantitative information about the dynamics of magma ascent and eruption that is difficult to obtain from other monitoring approaches. We show that the crystallinity of erupted ash particles is controlled by the magma supply rate (MSR); ash erupted during periods of high magma supply is substantially less crystalline than during periods of low magma supply. This correlation is most easily explained by efficient degassing at very low pressures (<<50 MPa) and degassing-driven crystallization controlled by the time available prior to eruption. Our data also suggest that the observed transition from intermittent Vulcanian explosions at low MSR to more continuous periods of Strombolian eruptions and lava fountains at high MSR can be explained by the rise of bubbles through (Strombolian) or trapping of bubbles beneath (Vulcanian) vent-capping, variably viscous (and crystalline) magma.

  3. Extrusion cycles during dome-building eruptions

    Science.gov (United States)

    de' Michieli Vitturi, M.; Clarke, A. B.; Neri, A.; Voight, B.

    2013-06-01

    We identify and quantify controls on the timescales and magnitudes of cyclic (periodic) volcanic eruptions using the numerical model DOMEFLOW (de' Michieli Vitturi et al., 2010) which was developed by the authors for magma systems of intermediate composition. DOMEFLOW treats the magma mixture as a liquid continuum with dispersed gas bubbles and crystals in thermodynamic equilibrium with the melt and assumes a modified Poiseuille form of the viscous term for fully developed laminar flow in a conduit of cylindrical cross-section. During ascent, magma pressure decreases and water vapor exsolves and partially degasses from the melt as the melt simultaneously crystallizes, causing changes in mixture density and viscosity. Two mechanisms previously proposed to cause periodic eruption behavior have been implemented in the model and their corresponding timescales explored. The first applies a stick-slip model in which motion of a shallow solid plug is resisted by static/dynamic friction, as described in Iverson et al. (2006). For a constant magma supply rate at depth, this mechanism yields cyclic extrusion with timescales of seconds to tens of seconds with values generally depending on assumed friction coefficients. The second mechanism does not consider friction but treats the plug as a high-viscosity Newtonian fluid. During viscous resistance, pressure beneath the degassed plug can increase sufficiently to overcome dome overburden, plug weight, and viscous forces, and ultimately drive the plug from the conduit. In this second model cycle periods are on the order of hours, and decrease with increasing magma supply rate until a threshold is reached, at which point periodicity disappears and extrusion rate becomes steady (vanishingly short periods). Magma volatile content for fixed chamber pressure has little effect on cycle timescales, but increasing volatile content increases mass flow rate and cycle magnitude as defined by the difference between maximum and minimum

  4. MULTI-LINE STOKES INVERSION FOR PROMINENCE MAGNETIC-FIELD DIAGNOSTICS

    International Nuclear Information System (INIS)

    Casini, R.; Lopez Ariste, A.; Paletou, F.; Leger, L.

    2009-01-01

    We present test results on the simultaneous inversion of the Stokes profiles of the He I lines at 587.6 nm (D 3 ) and 1083.0 nm in prominences (90 deg. scattering). We created data sets of synthetic Stokes profiles for the case of quiescent prominences (B -3 of the peak intensity for the polarimetric sensitivity of the simulated observations. In this work, we focus on the error analysis for the inference of the magnetic field vector, under the usual assumption that the prominence can be assimilated to a slab of finite optical thickness with uniform magnetic and thermodynamic properties. We find that the simultaneous inversion of the two lines significantly reduces the errors on the inference of the magnetic field vector, with respect to the case of single-line inversion. These results provide a solid justification for current and future instrumental efforts with multi-line capabilities for the observations of solar prominences and filaments.

  5. The ecology of prominences. [classification, morphology and significance to solar physics

    Science.gov (United States)

    Zirin, H.

    1979-01-01

    The paper discusses the roles of prominences in the solar scheme. Attention is given to classifications and the ways in which prominences exist: hydrostatic support, ballistic support, and magnetic support. In the case of ballistic support, surges are differentiated from sprays which involve the ejection of material that is already above the solar surface. Discussion also covers filimets and fibrils and the conditions for their appearance. It is proposed that most flares originate in prominence instabilities. In addition supergranulation is covered, noting the network is not seen on the boundary of unipolar regions. It is concluded that prominences play a critical role in flares and field reconnection, and the evolution of solar magnetic fields.

  6. What factors control the size of an eruption?

    Science.gov (United States)

    Gudmundsson, Agust

    2017-04-01

    For human society, eruption sizes (eruptive volumes or masses) are of the greatest concern. In particular, the largest eruptions, producing volumes of the order of hundreds or thousands of cubic kilometres, provide, together with meteoritic impacts, the greatest natural threats to mankind. Eruptive volumes tend to follow power laws so that most eruptions are comparatively small whereas a few are very large. It follows that a while during most ruptures of the source chambers a small fraction of the magma leaves the chamber, in some ruptures a very large fraction of the magma leaves the chamber. Most explosive eruptions larger than about 25 km3 are associated with caldera collapse. In the standard 'underpressure' ('lack of magmatic support') model, however, the collapse is the consequence, not the cause, of the large eruption. For poroelastic models, typically less than 4% of the magma in a felsic chamber and less than 0.1% of the magma in a mafic chamber leaves the chamber during rupture (and eventual eruption). In some caldera models, however, 20-70% of the magma is supposed to leave the chamber before the ring-fault forms and the caldera block begins to subside. In these models any amount of magma can flow out of the chamber following its rupture and there is apparently no way to forecast either the volume of magma injected from the chamber (hence the potential size of an eventual eruption) or the conditions for caldera collapse. An alternative model is proposed here. In this model normal (small) eruptions are controlled by standard poroelastity behaviour of the chamber, whereas large eruptions are controlled by chamber-volume reduction or shrinkage primarily through caldera/graben block subsidence into the chamber. Volcanotectonic stresses are then a major cause of ring-fault/graben boundary-fault formation. When large slips occur on these faults, the subsiding crustal block reduces the volume of the underlying chamber/reservoir, thereby maintaining its excess

  7. Toward detailed prominence seismology I. Computing accurate 2.5D magnetohydrodynamic equilibria

    OpenAIRE

    Blokland, J.W.S.; Keppens, R.

    2011-01-01

    Context. Prominence seismology exploits our knowledge of the linear eigenoscillations for representative magnetohydro- dynamic models of filaments. To date, highly idealized models for prominences have been used, especially with respect to the overall magnetic configurations. Aims. We initiate a more systematic survey of filament wave modes, where we consider full multi-dimensional models with twisted magnetic fields representative of the surrounding magnetic flux rope. This requires the abil...

  8. Quiescent Prominences in the Era of ALMA. II. Kinetic Temperature Diagnostics

    Science.gov (United States)

    Gunár, Stanislav; Heinzel, Petr; Anzer, Ulrich; Mackay, Duncan H.

    2018-01-01

    We provide the theoretical background for diagnostics of the thermal properties of solar prominences observed by the Atacama Large Millimeter/submillimeter Array (ALMA). To do this, we employ the 3D Whole-Prominence Fine Structure (WPFS) model that produces synthetic ALMA-like observations of a complex simulated prominence. We use synthetic observations derived at two different submillimeter/millimeter (SMM) wavelengths—one at a wavelength at which the simulated prominence is completely optically thin and another at a wavelength at which a significant portion of the simulated prominence is optically thick—as if these were the actual ALMA observations. This allows us to develop a technique for an analysis of the prominence plasma thermal properties from such a pair of simultaneous high-resolution ALMA observations. The 3D WPFS model also provides detailed information about the distribution of the kinetic temperature and the optical thickness along any line of sight. We can thus assess whether the measure of the kinetic temperature derived from observations accurately represents the actual kinetic temperature properties of the observed plasma. We demonstrate here that in a given pixel the optical thickness at the wavelength at which the prominence plasma is optically thick needs to be above unity or even larger to achieve a sufficient accuracy of the derived information about the kinetic temperature of the analyzed plasma. Information about the optical thickness cannot be directly discerned from observations at the SMM wavelengths alone. However, we show that a criterion that can identify those pixels in which the derived kinetic temperature values correspond well to the actual thermal properties in which the observed prominence can be established.

  9. Eruption and emplacement timescales of ignimbrite super-eruptions from thermo-kinetics of glass shards

    Directory of Open Access Journals (Sweden)

    Yan eLavallée

    2015-02-01

    Full Text Available Super-eruptions generating hundreds of cubic kilometres of pyroclastic density currents are commonly recorded by thick, welded and lava-like ignimbrites. Despite the huge environmental impact inferred for this type of eruption, little is yet known about the timescales of deposition and post-depositional flow. Without these timescales, the critical question of the duration of any environmental impact, and the ensuing gravity of its effects for the Earth system, eludes us. The eruption and welding of ignimbrites requires three transects of the glass transition. Magma needs to: 1 fragment during ascent, 2 liquefy and relax during deposition, agglutination and welding (sintering, and 3 quench by cooling into the glassy state. Here we show that welding is a rapid, syn-depositional process and that the welded ignimbrite sheet may flow for up to a few hours before passing through the glass transition a final time. Geospeedometry reveals that the basal vitrophyre of the Grey’s Landing ignimbrite underwent the glass transition at a rate of ~0.1 °C.min^-1 at 870 °C; that is, 30-180 °C below pre-eruptive geothermometric estimates. Application of a 1-D cooling model constrains the timescale of deposition, agglutination, and welding of the basal vitrophyre to less than 1 hour, and possibly even tens of minutes. Thermo-mechanical iteration of the sintering process indicates an optimal temperature solution for the emplacement of the vitrophyres at 966 °C. The vitrophyres reveal a Newtonian rheology up to 46 MPa, which suggests that the ash particles annealed entirely during welding and that viscous energy dissipation is unlikely from loading conditions alone, unless shear stresses imposed by the overlying ash flow were excessively high and sustained over long distances. The findings underline the value of the term 'lava-like' flow to describe the end rheology of Snake River-type ignimbrites, fully consistent with the typical lithofacies observed.

  10. 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.

  11. Hunting for eruption ages in accessory minerals

    Science.gov (United States)

    Vazquez, J. A.

    2012-12-01

    A primary goal in geochronology is to provide precise and accurate ages for tephras that serve as chronostratigraphic markers for constraining the timing and rates of volcanism, sedimentation, climate change, and catastrophic events in Earth history. Zircon remains the most versatile accessory mineral for dating silicic tephras due to its common preservation in distal pyroclastic deposits, as well as the robustness of its U-Pb and U-series systems even after host materials have been hydrothermally altered or weathered. Countless studies document that zircon may be complexly zoned in age due to inheritance, contamination, recycling of antecrysts, protracted crystallization in long-lived magma reservoirs, or any combination of these. Other accessory minerals such as allanite or chevkinite can retain similar records of protracted crystallization. If the goal is to date the durations of magmatic crystallization, differentiation, and/or magma residence, then these protracted chronologies within and between accessory minerals are a blessing. However, if the goal is to date the timing of eruption with high precision, i.e., absolute ages with millennial-scale uncertainties, then this age zoning is a curse. Observations from ion microprobe 238U-230Th dating of Pleistocene zircon and allanite provide insight into the record of near-eruption crystallization in accessory minerals and serve as a guide for high-precision whole-crystal dating. Although imprecise relative to conventional techniques, ion probe analysis allows high-spatial resolution 238U-230Th dating that can document multi-millennial age distributions at the crystal scale. Analysis of unpolished rims and continuous depth profiling of zircon from small and large volume eruptions (e.g., Coso, Mono Craters, Yellowstone) reveals that the final several micrometers of crystallization often yield ages that are indistinguishable from associated eruption ages from the 40Ar/39Ar or (U-Th)/He methods. Using this approach, we

  12. POLYMORPHOUS LIGHT ERUPTION – A REVIEW

    Directory of Open Access Journals (Sweden)

    Yogeesh Hosahalli Rajaiah

    2013-07-01

    Full Text Available Polymprhouos light eruption is the most common idiopathic photodermatosis. It is a sun induced cutaneous reaction characterized by onset itchy erathematous papules, plaques, vesicles or erythema multiforme type of lesions after brief exposure to sunlight. Sun-exposed areas of the body or rarely the partially covered areas are commonly involved. PLE is more common in temperate climates than in tropics. It begins usually at the onset of summer and moderates as the summer progresses. In most patients it usually runs a benign course. Diagnosis is mainly on clinical grounds. Therapy involves avoidance of sun-exposure and use of sunscreens. Cases not responding to simple measures require PUVA (Psoralen and Ultraviolet A or UVB (ultraviolet B therapy. Other alternative suggested therapies with variable success include oral hydroxychloroquine, beta-carotene, thalidomide and nicotinamide.

  13. Talon cusp on palatally erupted mesiodens

    Directory of Open Access Journals (Sweden)

    Ashalata Gannepalli

    2017-01-01

    Full Text Available Talon cusp is an accessory cusp-like structure or an extra cusp on an anterior tooth arising as a result of evagination on the surface of the crown before calcification has occurred. The cusp is composed of normal enamel and dentin containing varying extensions of pulp tissue. It is associated with few developmental anomalies such as peg laterals, dens invaginatus, and mesiodens. Mesiodens is a supernumerary tooth located in the premaxillary central incisor region which is supplemental or rudimentary type. Association of mesiodens with talon cusp is a rare occurrence with 25 cases reported. The presence of Talon cusp or a supernumerary tooth – mesiodens – leads to clinical implications such as poor esthetics, crowding, rotations, and also occlusal discrepancies. In this report, we present a case report of an 18-year-old male having a talon cusp on palatally erupted mesiodens.

  14. Sudden eruption of multiple Meyerson naevi

    Directory of Open Access Journals (Sweden)

    Sandra Jerkovic Gulin

    2017-03-01

    Full Text Available We present a case of a young patient presenting with a six-month history of multiple squamous pink and light brown papules surrounded by symmetrical eczema on the trunk. Dermoscopy revealed light brown structureless and avascular lesions with an erythematous scaly halo. The patient denied the presence of naevi on the sites of the newly emerging changes. Histopathology revealed acanthotic epidermis and linear clusters of morphologically normal naevi cells in the upper dermis, infiltration of lymphocytes, plasma cells, eosinophils and mild spongiosis in the  dermis. Topical betamethasone/gentamicin ointment twice daily for 10 days was prescribed. The erythematous scaly area around lesions completely disappeared on the follow-up visit after six months. This is a unique case of a sudden appearance of newly formed multiple benign dermal naevi with Meyerson phenomenon—the sudden eruption of multiple Meyerson naevi.

  15. Imatinib mesylate-induced lichenoid drug eruption.

    Science.gov (United States)

    Penn, Erin H; Chung, Hye Jin; Keller, Matthew

    2017-03-01

    Imatinib mesylate (imatinib) is a tyrosine kinase inhibitor initially approved by the US Food and Drug Administration in 2001 for chronic myeloid leukemia (CML). Since then, the number of indicated uses for imatinib has substantially increased. It is increasingly important that dermatologists recognize adverse cutaneous manifestations of imatinib and are aware of their management and outcomes to avoid unnecessarily discontinuing a potentially lifesaving medication. Adverse cutaneous manifestations in response to imat-inib are not infrequent and can include dry skin, alopecia, facial edema, and photosensitivity rash. Other less common manifestations include exfoliative dermatitis, nail disorders, psoriasis, folliculitis, hypotrichosis, urticaria, petechiae, Stevens-Johnson syndrome, erythema multiforme, Sweet syndrome, and leukocytoclastic vasculitis. We report a case of imatinib-induced lichenoid drug eruption (LDE), a rare cutaneous manifestation, along with a review of the literature.

  16. Using Infrasound and Machine Learning for Monitoring Plinian Volcanic Eruptions

    Science.gov (United States)

    Ham, F. M.; Iyengar, I.; Hambebo, B. M.; Garces, M. A.; Deaton, J.; Perttu, A.; Williams, B.

    2012-12-01

    Large plinian volcanic eruptions can inject a substantial amount of volcanic gas and ash into the stratosphere. This can present a severe hazard to commercial air traffic. A hazardous Icelandic volcanic ash-eruption was reported on April 14, 2010. This resulted in London's aviation authority to issue an alert that an ash plume was moving from an eruption in Iceland towards northwestern Europe. This eruption resulted in the closure of large areas of European airspace. Large plinian volcanic eruptions radiate infrasonic signals that can be detected by a global infrasound array network. To reduce potential hazards for commercial aviation from volcanic ash, these infrasound sensor arrays have been used to detect infrasonic signals released by sustained volcanic eruptions that can inject ash into the stratosphere at aircraft's cruising altitudes, typically in the order of 10km. A system that is capable of near, real-time eruption detection and discrimination of plinian eruptions from other natural phenomena that can produce infrasound with overlapping spectral content (0.01 to 0.1 Hz) is highly desirable to provide ash-monitoring for commercial aviation. In the initial study, cepstral features were extracted from plinian volcanic eruptions and mountain associated wave infrasound signals. These feature vectors were then used to train and test a two-module neural network classifier (radial basis function neural networks were used for each module). One module is dedicated to classifying plinian volcanic eruptions, the other mountain associated waves. Using an independent validation dataset, the classifier's correct classification rate was 91.5%. Then a different two-module neural network classifier was designed to discriminate between plinian volcanic eruptions and a collection of infrasound signals that are not-of-interest but have spectral content that overlaps with the volcano signals. One module is again dedicated to classifying plinian volcanic eruptions, however, in

  17. The prominence-corona interface compared with the chromosphere-corona transition region

    Science.gov (United States)

    Orrall, F. Q.; Schmahl, E. J.

    1976-01-01

    The intensities of 52 optically thin EUV emission lines formed at temperatures of 350,000 to 2.2 million K in nine hedgerow prominences observed at the limb are compared with the intensities of the same lines formed within network cells at the center of the solar disk in order to compare the prominence-corona interface (PC) with the chromosphere-corona transition region (CC). It is found for all nine prominences that the ratio of the intensity of a line measured in a cell to that in a prominence decreases with increasing temperature approximately as the -0.6 power of temperature. This ratio is used as the basis for comparing the PC with the CC in the framework of two different geometries wherein the prominence consists of one or more identical fully resolved slabs or threads in the line of sight or contains one or more identical unresolved cylindrical threads. It is concluded that three effects may contribute to the systematic difference between the PC and the CC: (1) the pressure within the PC might increase outward; (2) the temperature gradient within the PC might increase more slowly with temperature than in the CC; and (3) the unresolved internal geometry of a prominence can directly explain some, but not all, of the systematic difference.

  18. A Parametric Study of Erupting Flux Rope Rotation: Modeling the 'Cartwheel CME' on 9 April 2008

    Science.gov (United States)

    Kliem, B.; Toeroek, T.; Thompson, W. T.

    2012-01-01

    The rotation of erupting filaments in the solar corona is addressed through a parametric simulation study of unstable, rotating flux ropes in bipolar force-free initial equilibrium. The Lorentz force due to the external shear-field component and the relaxation of tension in the twisted field are the major contributors to the rotation in this model, while reconnection with the ambient field is of minor importance, due to the field's simple structure. In the low-beta corona, the rotation is not guided by the changing orientation of the vertical field component's polarity inversion line with height. The model yields strong initial rotations which saturate in the corona and differ qualitatively from the profile of rotation vs. height obtained in a recent simulation of an eruption without preexisting flux rope. Both major mechanisms writhe the flux rope axis, converting part of the initial twist helicity, and produce rotation profiles which, to a large part, are very similar within a range of shear-twist combinations. A difference lies in the tendency of twist-driven rotation to saturate at lower heights than shear-driven rotation. For parameters characteristic of the source regions of erupting filaments and coronal mass ejections, the shear field is found to be the dominant origin of rotations in the corona and to be required if the rotation reaches angles of order 90 degrees and higher; it dominates even if the twist exceeds the threshold of the helical kink instability. The contributions by shear and twist to the total rotation can be disentangled in the analysis of observations if the rotation and rise profiles are simultaneously compared with model calculations. The resulting twist estimate allows one to judge whether the helical kink instability occurred. This is demonstrated for the erupting prominence in the "Cartwheel CME" on 9 April 2008, which has shown a rotation of approximately 115 deg. up to a height of 1.5 Solar R above the photosphere. Out of a range of

  19. A Guillain-Barré syndrome variant with prominent facial diplegia.

    Science.gov (United States)

    Susuki, Keiichiro; Koga, Michiaki; Hirata, Koichi; Isogai, Emiko; Yuki, Nobuhiro

    2009-11-01

    To determine the clinical features of a Guillain-Barré syndrome variant with prominent facial diplegia, we retrospectively reviewed approximately 8,600 cases referred to our neuroimmunological laboratory for serological tests during the past seven years. Patients' histories, neurological signs, and laboratory and electrophysiological data were clarified based on their clinical records. Sera obtained during the acute phase were tested for prior infectious serology and anti-ganglioside antibodies. In 22 patients, clinical signs such as acute progressive bifacial weakness, paresthesias in the distal dominant limbs, and hypo- or areflexia, were compatible with a Guillain-Barré syndrome variant, facial diplegia and paresthesias. Other cranial nerve involvements, limb weakness, and ataxia were absent or minimal. Clinical courses were monophasic, the nadir being reached within four weeks. Eighteen patients (86%) had had infectious symptoms within the four weeks preceding the onset of neurological illness. In the infection serology tests, anti-cytomegalovirus IgM antibodies were the most frequent (35%). All the patients had cerebrospinal fluid albuminocytologic dissociation. In nerve conduction studies, 14 (64%) showed demyelination in their limbs. Anti-GM2 IgM antibodies were detected in four patients who had anti-cytomegalovirus IgM antibodies. Patients with conditions similar to facial diplegia and paresthesias, but lacking either distal paresthesias or hyporeflexia, were regarded as having marginal facial diplegia and paresthesias, because they also frequently had features of Guillain-Barré syndrome, such as an antecedent infection or cerebrospinal fluid albuminocytologic dissociation. Our findings are further evidence of a facial variant of Guillain-Barré syndrome and provide important information essential for its diagnosis.

  20. Defensive mobilization in specific phobia: fear specificity, negative affectivity, and diagnostic prominence.

    Science.gov (United States)

    McTeague, Lisa M; Lang, Peter J; Wangelin, Bethany C; Laplante, Marie-Claude; Bradley, Margaret M

    2012-07-01

    Understanding of exaggerated responsivity in specific phobia-its physiology and neural mediators-has advanced considerably. However, despite strong phenotypic evidence that prominence of specific phobia relative to co-occurring conditions (i.e., principal versus nonprincipal disorder) is associated with dramatic differences in subjective distress, there is yet no consideration of such comorbidity issues on objective defensive reactivity. A community sample of specific phobia (n = 74 principal; n = 86 nonprincipal) and control (n = 76) participants imagined threatening and neutral events while acoustic startle probes were presented and eyeblinks (orbicularis occuli) recorded. Changes in heart rate, skin conductance level, and facial expressivity were also measured. Principal specific phobia patients far exceeded control participants in startle reflex and autonomic reactivity during idiographic fear imagery. Distinguishing between single and multiple phobias within principal phobia and comparing these with nonprincipal phobia revealed a continuum of decreasing defensive mobilization: single patients were strongly reactive, multiple patients were intermediate, and nonprincipal patients were attenuated-the inverse of measures of pervasive anxiety and dysphoria (i.e., negative affectivity). Further, as more disorders supplanted specific phobia from principal disorder, overall defensive mobilization was systematically more impaired. The exaggerated responsivity characteristic of specific phobia is limited to those patients for whom circumscribed fear is the most impairing condition and coincident with little additional affective psychopathology. As specific phobia is superseded in severity by broad and chronic negative affectivity, defensive reactivity progressively diminishes. Focal fears may still be clinically significant but not reflected in objective defensive mobilization. Copyright © 2012 Society of Biological Psychiatry. Published by Elsevier Inc. All rights

  1. Impact of explosive eruption scenarios at Vesuvius

    Science.gov (United States)

    Zuccaro, G.; Cacace, F.; Spence, R. J. S.; Baxter, P. J.

    2008-12-01

    In the paper the first attempt at the definition of a model to assess the impact of a range of different volcanic hazards on the building structures is presented. This theoretical approach has been achieved within the activities of the EXPLORIS Project supported by the EU. A time history for Sub-Plinian I eruptive scenario of the Vesuvius is assumed by taking advantage of interpretation of historical reports of volcanic crises of the past [Carafa, G. 1632. In opusculum de novissima Vesuvij conflagratione, epistola isagogica, 2 a ed. Napoli, Naples; Mascolo, G.B., 1634. De incendio Vesuvii excitato xvij. Kal. Ianuar. anno trigesimo primo sæculi Decimiseptimi libri X. Cum Chronologia superiorum incendiorum; & Ephemeride ultimi. Napoli; Varrone, S., 1634. Vesuviani incendii historiae libri tres. Napoli], numerical simulations [Neri, A., Esposti Ongaro, T., Macedonio, G., Gidaspow, D., 2003. Multiparticle simulation of collapsing volcanic columns and pyroclastic flows. J. Geophys. Res. Lett. 108, 2202. doi:10.1029/2001 JB000508; Macedonio, G., Costa, A., Longo, A., 2005. HAZMAP: a computer model for volcanic ash fallout and assessment of subsequent hazard. Comput. Geosci. 31,837-845; Costa, A., Macedonio, G., Folch, A., 2006. A three-dimensional Eulerian model for transport and deposition of volcanic ashes. Earth Planet. Sci. Lett. 241,634-647] and experts' elicitations [Aspinall, W.P., 2006. Structured elicitation of expert judgment for probabilistic hazard and risk assessment in volcanic eruptions. In: Mader, H.M. Coles, S.G. Connor, C.B. Connor, L.J. (Eds), Statistics in Volcanology. Geological Society of London on behalf of IAVCEI, pp.15-30; Woo, G., 1999. The Mathematics of Natural Catastrophes. Imperial College Press, London] from which the impact on the building structures is derived. This is achieved by an original definition of vulnerability functions for multi-hazard input and a dynamic cumulative damage model. Factors affecting the variability of the final

  2. Peak flow responses to landscape disturbances caused by the cataclysmic 1980 eruption of Mount St. Helens, Washington

    Science.gov (United States)

    Major, Jon J.; Mark, Linda E.

    2006-01-01

    Years of discharge measurements that precede and follow the cataclysmic 1980 eruption of Mount St. Helens, Washington, provide an exceptional opportunity to examine the responses of peak flows to abrupt, widespread, devastating landscape disturbance. Multiple basins surrounding Mount St. Helens (300–1300 km2 drainage areas) were variously disturbed by: (1) a debris avalanche that buried 60 km2 of valley; (2) a lateral volcanic blast and associated pyroclastic flow that destroyed 550 km2 of mature forest and blanketed the landscape with silt-capped lithic tephra; (3) debris flows that reamed riparian corridors and deposited tens to hundreds of centimeters of gravelly sand on valley floors; and (4) a Plinian tephra fall that blanketed areas proximal to the volcano with up to tens of centimeters of pumiceous silt, sand, and gravel. The spatially complex disturbances produced a variety of potentially compensating effects that interacted with and influenced hydrological responses. Changes to water transfer on hillslopes and to flow storage and routing along channels both enhanced and retarded runoff. Rapid post-eruption modifications of hillslope surface textures, adjustments of channel networks, and vegetation recovery, in conjunction with the complex nature of the eruptive impacts and strong seasonal variability in regional climate hindered a consistent or persistent shift in peak discharges. Overall, we detected a short-lived (5–10 yr) increase in the magnitudes of autumn and winter peak flows. In general, peak flows were larger, and moderate to large flows (>Q2 yr) were more substantively affected than predicted by early modeling efforts. Proportional increases in the magnitudes of both small and large flows in basins subject to severe channel disturbances, but not in basins subject solely to hillslope disturbances, suggest that eruption-induced modifications to flow efficiency along alluvial channels that have very mobile beds differentially affected flows of

  3. Tephra from andesitic Shiveluch volcano, Kamchatka, NW Pacific: chronology of explosive eruptions and geochemical fingerprinting of volcanic glass

    Science.gov (United States)

    Ponomareva, Vera; Portnyagin, Maxim; Pevzner, Maria; Blaauw, Maarten; Kyle, Philip; Derkachev, Alexander

    2015-07-01

    The ~16-ka-long record of explosive eruptions from Shiveluch volcano (Kamchatka, NW Pacific) is refined using geochemical fingerprinting of tephra and radiocarbon ages. Volcanic glass from 77 prominent Holocene tephras and four Late Glacial tephra packages was analyzed by electron microprobe. Eruption ages were estimated using 113 radiocarbon dates for proximal tephra sequence. These radiocarbon dates were combined with 76 dates for regional Kamchatka marker tephra layers into a single Bayesian framework taking into account the stratigraphic ordering within and between the sites. As a result, we report ~1,700 high-quality glass analyses from Late Glacial-Holocene Shiveluch eruptions of known ages. These define the magmatic evolution of the volcano and provide a reference for correlations with distal fall deposits. Shiveluch tephras represent two major types of magmas, which have been feeding the volcano during the Late Glacial-Holocene time: Baidarny basaltic andesites and Young Shiveluch andesites. Baidarny tephras erupted mostly during the Late Glacial time (~16-12.8 ka BP) but persisted into the Holocene as subordinate admixture to the prevailing Young Shiveluch andesitic tephras (~12.7 ka BP-present). Baidarny basaltic andesite tephras have trachyandesite and trachydacite (SiO2 SiO2 > 71.5 wt%). Strongly calc-alkaline medium-K characteristics of Shiveluch volcanic glasses along with moderate Cl, CaO and low P2O5 contents permit reliable discrimination of Shiveluch tephras from the majority of other large Holocene tephras of Kamchatka. The Young Shiveluch glasses exhibit wave-like variations in SiO2 contents through time that may reflect alternating periods of high and low frequency/volume of magma supply to deep magma reservoirs beneath the volcano. The compositional variability of Shiveluch glass allows geochemical fingerprinting of individual Shiveluch tephra layers which along with age estimates facilitates their use as a dating tool in paleovolcanological

  4. The 808 nm Laser-Assisted Surgery as an Adjunct to Orthodontic Treatment of Delayed Tooth Eruption.

    Science.gov (United States)

    Seifi, Massoud; Vahid-Dastjerdi, Elahe; Ameli, Nazila; Badiee, Mohammad-Reza; Younessian, Farnaz; Amdjadi, Parisa

    2013-01-01

    Failure of teeth to erupt from gingival tissues at usual developmental time is called delayed tooth eruption (DTE). Delayed tooth eruption lead to prolonged fixed orthodontic treatment and its eventual complications. The purpose of the present study was to evaluate the effect of laser-assisted (808 nm) surgical uncovering, on the tooth emergence and orthodontic treatment of DTE. A total of 16 orthodontic patients were included in this study and were equally assigned to an experimental and a control group. Subjects for experiment consisted of eight patients (6 girls and 2 boys) with a mean age of 14±0.9 years. All patients exhibited delayed second premolar eruption. The laser wavelength was 810 nm and it was set in a continuous wave mode at a power output of 1.6 watt with a 0.3-mm diameter fiber tip. When the target tissue was sufficiently anesthetized, the tip was directed at an angle of 10 to 20 degrees to the tissue (light contact mode); and was applied continuously for approximately 12 Seconds until an acceptable tooth exposure area was visible. The facial axis of the clinical crown (FACC) line represents the most prominent portion of the facial central lobe for premolars. All orthodontic brackets are aligned along this reference and are located on FA (Facial Axis) point. The standard for adequate tooth eruption was the accessibility of facial axis of the clinical crown (FACC) for bonding the brackets. Data gathered from the patients were statistically surveyed and compared by means of Tukey's Test and Analysis of Variance (ANOVA). All patients showed good gingival status, no significant bleeding during or immediately after the surgery, and acceptable level of healing after laser surgery. The biologic width of the teeth was preserved and no violation of this important periodontal parameter was observed. The average time for accessing the FA point in experimental group was 11±1.1 weeks and the mentioned period was increased to 25±1.8 weeks in control group

  5. Database for potential hazards from future volcanic eruptions in California

    Science.gov (United States)

    White, Melissa N.; Ramsey, David W.; Miller, C. Dan

    2011-01-01

    More than 500 volcanic vents have been identified in the State of California. At least 76 of these vents have erupted, some repeatedly, during the past 10,000 yr. Past volcanic activity has ranged in scale and type from small rhyolitic and basaltic eruptions through large catastrophic rhyolitic eruptions. Sooner or later, volcanoes in California will erupt again, and they could have serious impacts on the health and safety of the State's citizens as well as on its economy. This report describes the nature and probable distribution of potentially hazardous volcanic phenomena and their threat to people and property. It includes hazard-zonation maps that show areas relatively likely to be affected by future eruptions in California. This digital release contains information from maps of potential hazards from future volcanic eruptions in the state of California, published as Plate 1 in U.S. Geological Survey Bulletin 1847. The main component of this digital release is a spatial database prepared using geographic information systems (GIS) applications. This release also contains links to files to view or print the map plate, main report text, and accompanying hazard tables from Bulletin 1847. It should be noted that much has been learned about the ages of eruptive events in the State of California since the publication of Bulletin 1847 in 1989. For the most up to date information on the status of California volcanoes, please refer to the U.S. Geological Survey Volcano Hazards Program website.

  6. The Origin, Early Evolution and Predictability of Solar Eruptions

    Science.gov (United States)

    Green, Lucie M.; Török, Tibor; Vršnak, Bojan; Manchester, Ward; Veronig, Astrid

    2018-02-01

    Coronal mass ejections (CMEs) were discovered in the early 1970s when space-borne coronagraphs revealed that eruptions of plasma are ejected from the Sun. Today, it is known that the Sun produces eruptive flares, filament eruptions, coronal mass ejections and failed eruptions; all thought to be due to a release of energy stored in the coronal magnetic field during its drastic reconfiguration. This review discusses the observations and physical mechanisms behind this eruptive activity, with a view to making an assessment of the current capability of forecasting these events for space weather risk and impact mitigation. Whilst a wealth of observations exist, and detailed models have been developed, there still exists a need to draw these approaches together. In particular more realistic models are encouraged in order to asses the full range of complexity of the solar atmosphere and the criteria for which an eruption is formed. From the observational side, a more detailed understanding of the role of photospheric flows and reconnection is needed in order to identify the evolutionary path that ultimately means a magnetic structure will erupt.

  7. Magmatic Densities Control Erupted Volumes in Icelandic Volcanic Systems

    Directory of Open Access Journals (Sweden)

    Margaret Hartley

    2018-04-01

    Full Text Available Magmatic density and viscosity exert fundamental controls on the eruptibility of magmas. In this study, we investigate the extent to which magmatic physical properties control the eruptibility of magmas from Iceland's Northern Volcanic Zone (NVZ. By studying subaerial flows of known age and volume, we are able to directly relate erupted volumes to magmatic physical properties, a task that has been near-impossible when dealing with submarine samples dredged from mid-ocean ridges. We find a strong correlation between magmatic density and observed erupted volumes on the NVZ. Over 85% of the total volume of erupted material lies close to a density and viscosity minimum that corresponds to the composition of basalts at the arrival of plagioclase on the liquidus. These magmas are buoyant with respect to the Icelandic upper crust. However, a number of small-volume eruptions with densities greater than typical Icelandic upper crust are also found in Iceland's neovolcanic zones. We use a simple numerical model to demonstrate that the eruption of magmas with higher densities and viscosities is facilitated by the generation of overpressure in magma chambers in the lower crust and uppermost mantle. This conclusion is in agreement with petrological constraints on the depths of crystallization under Iceland.

  8. 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.

  9. The association between childhood obesity and tooth eruption.

    Science.gov (United States)

    Must, Aviva; Phillips, Sarah M; Tybor, David J; Lividini, Keith; Hayes, Catherine

    2012-10-01

    Obesity is a growth-promoting process as evidenced by its effect on the timing of puberty. Although studies are limited, obesity has been shown to affect the timing of tooth eruption. Both the timing and sequence of tooth eruption are important to overall oral health. The purpose of this study was to examine the association between obesity and tooth eruption. Data were combined from three consecutive cycles (2001-2006) of the National Health and Nutrition Examination Survey (NHANES) and analyzed to examine associations between the number of teeth erupted (NET) and obesity status (BMI z-score >95th percentile BMI relative to the Centers for Disease Control and Prevention (CDC) growth reference) among children 5 up to 14 years of age, controlling for potential confounding by age, gender, race, and socioeconomic status (SES). Obesity is significantly associated with having a higher average NET during the mixed dentition period. On average, teeth of obese children erupted earlier than nonobese children with obese children having on average 1.44 more teeth erupted than nonobese children, after adjusting for age, gender, and race/ethnicity (P erupted than nonobese children after adjusting for gender, age, and race. These findings may have clinical importance in the area of dental and orthodontic medicine both in terms of risk for dental caries due to extended length of time exposed in the oral cavity and sequencing which may increase the likelihood of malocclusions.

  10. Tooth eruption results from bone remodelling driven by bite forces sensed by soft tissue dental follicles: a finite element analysis.

    Science.gov (United States)

    Sarrafpour, Babak; Swain, Michael; Li, Qing; Zoellner, Hans

    2013-01-01

    Intermittent tongue, lip and cheek forces influence precise tooth position, so we here examine the possibility that tissue remodelling driven by functional bite-force-induced jaw-strain accounts for tooth eruption. Notably, although a separate true 'eruptive force' is widely assumed, there is little direct evidence for such a force. We constructed a three dimensional finite element model from axial computerized tomography of an 8 year old child mandible containing 12 erupted and 8 unerupted teeth. Tissues modelled included: cortical bone, cancellous bone, soft tissue dental follicle, periodontal ligament, enamel, dentine, pulp and articular cartilage. Strain and hydrostatic stress during incisive and unilateral molar bite force were modelled, with force applied via medial and lateral pterygoid, temporalis, masseter and digastric muscles. Strain was maximal in the soft tissue follicle as opposed to surrounding bone, consistent with follicle as an effective mechanosensor. Initial numerical analysis of dental follicle soft tissue overlying crowns and beneath the roots of unerupted teeth was of volume and hydrostatic stress. To numerically evaluate biological significance of differing hydrostatic stress levels normalized for variable finite element volume, 'biological response units' in Nmm were defined and calculated by multiplication of hydrostatic stress and volume for each finite element. Graphical representations revealed similar overall responses for individual teeth regardless if incisive or right molar bite force was studied. There was general compression in the soft tissues over crowns of most unerupted teeth, and general tension in the soft tissues beneath roots. Not conforming to this pattern were the unerupted second molars, which do not erupt at this developmental stage. Data support a new hypothesis for tooth eruption, in which the follicular soft tissues detect bite-force-induced bone-strain, and direct bone remodelling at the inner surface of the

  11. Catastrophic caldera-forming eruptions II: The subordinate role of magma buoyancy as an eruption trigger

    Science.gov (United States)

    Gregg, Patricia M.; Grosfils, Eric B.; de Silva, Shanaka L.

    2015-10-01

    Recent analytical investigations have suggested that magma buoyancy is critical for triggering catastrophic caldera forming eruptions. Through detailed assessment of these approaches, we illustrate how analytical models have been misapplied for investigating buoyancy and are, therefore, incorrect and inconclusive. Nevertheless, the hypothesis that buoyancy is the critical trigger for larger eruptions warrants further investigation. As such, we utilize viscoelastic finite element models that incorporate buoyancy to test overpressure evolution and mechanical failure in the roof due to the coalescence of large buoyant magma bodies for two model cases. In the first case, we mimic empirical approaches and include buoyancy as an explicit boundary condition. In the second set of models, buoyancy is calculated implicitly due to the density contrast between the magma in the reservoir and the host rock. Results from these numerical experiments indicate that buoyancy promotes only minimal overpressurization of large silicic magma reservoirs (failure is predicted along the magma chamber boundary due to buoyancy in large reservoirs. Rather, compressional stresses are observed due to buoyant magma focusing away from the edges of the reservoir and toward the center. Given the shortcomings of the analytical implementations and the results from the numerical experiments, we conclude that buoyancy does not provide an eruption triggering mechanism for large silicic systems. Therefore, correlations of buoyancy with magma residence times, the eruption frequency-volume relationship, and the dimensions of calderas are re-assessed. We find a causal relationship with magma reservoir volume that implicates the mechanical conditions of the host rock as a primary control on eruption frequency. As magma reservoirs grow in size (> 100 km3) they surpass a rheological threshold where their subsequent evolution is controlled by host rock mechanics. Consequently, this results in a thermomechanical

  12. Historic hydrovolcanism at Deception Island (Antarctica): implications for eruption hazards

    Science.gov (United States)

    Pedrazzi, Dario; Németh, Károly; Geyer, Adelina; Álvarez-Valero, Antonio M.; Aguirre-Díaz, Gerardo; Bartolini, Stefania

    2018-01-01

    Deception Island (Antarctica) is the southernmost island of the South Shetland Archipelago in the South Atlantic. Volcanic activity since the eighteenth century, along with the latest volcanic unrest episodes in the twentieth and twenty-first centuries, demonstrates that the volcanic system is still active and that future eruptions are likely. Despite its remote location, the South Shetland Islands are an important touristic destination during the austral summer. In addition, they host several research stations and three summer field camps. Deception Island is characterised by a Quaternary caldera system with a post-caldera succession and is considered to be part of an active, dispersed (monogenetic), volcanic field. Historical post-caldera volcanism on Deception Island involves monogenetic small-volume (VEI 2-3) eruptions such forming cones and various types of hydrovolcanic edifices. The scientific stations on the island were destroyed, or severely damaged, during the eruptions in 1967, 1969, and 1970 mainly due to explosive activity triggered by the interaction of rising (or erupting) magma with surface water, shallow groundwater, and ice. We conducted a detailed revision (field petrology and geochemistry) of the historical hydrovolcanic post-caldera eruptions of Deception Island with the aim to understand the dynamics of magma-water interaction, as well as characterise the most likely eruptive scenarios from future eruptions. We specifically focused on the Crimson Hill (estimated age between 1825 and 1829), and Kroner Lake (estimated age between 1829 and 1912) eruptions and 1967, 1969, and 1970 events by describing the eruption mechanisms related to the island's hydrovolcanic activity. Data suggest that the main hazards posed by volcanism on the island are due to fallout, ballistic blocks and bombs, and subordinate, dilute PDCs. In addition, Deception Island can be divided into five areas of expected activity due to magma-water interaction, providing additional

  13. First recorded eruption of Nabro volcano, Eritrea, 2011.

    Science.gov (United States)

    Goitom, Berhe; Oppenheimer, Clive; Hammond, James O S; Grandin, Raphaël; Barnie, Talfan; Donovan, Amy; Ogubazghi, Ghebrebrhan; Yohannes, Ermias; Kibrom, Goitom; Kendall, J-Michael; Carn, Simon A; Fee, David; Sealing, Christine; Keir, Derek; Ayele, Atalay; Blundy, Jon; Hamlyn, Joanna; Wright, Tim; Berhe, Seife

    We present a synthesis of diverse observations of the first recorded eruption of Nabro volcano, Eritrea, which began on 12 June 2011. While no monitoring of the volcano was in effect at the time, it has been possible to reconstruct the nature and evolution of the eruption through analysis of regional seismological and infrasound data and satellite remote sensing data, supplemented by petrological analysis of erupted products and brief field surveys. The event is notable for the comparative rarity of recorded historical eruptions in the region and of caldera systems in general, for the prodigious quantity of SO 2 emitted into the atmosphere and the significant human impacts that ensued notwithstanding the low population density of the Afar region. It is also relevant in understanding the broader magmatic and tectonic significance of the volcanic massif of which Nabro forms a part and which strikes obliquely to the principal rifting directions in the Red Sea and northern Afar. The whole-rock compositions of the erupted lavas and tephra range from trachybasaltic to trachybasaltic andesite, and crystal-hosted melt inclusions contain up to 3,000 ppm of sulphur by weight. The eruption was preceded by significant seismicity, detected by regional networks of sensors and accompanied by sustained tremor. Substantial infrasound was recorded at distances of hundreds to thousands of kilometres from the vent, beginning at the onset of the eruption and continuing for weeks. Analysis of ground deformation suggests the eruption was fed by a shallow, NW-SE-trending dike, which is consistent with field and satellite observations of vent distributions. Despite lack of prior planning and preparedness for volcanic events in the country, rapid coordination of the emergency response mitigated the human costs of the eruption.

  14. [Effects of volcanic eruptions on human health in Iceland. Review].

    Science.gov (United States)

    Gudmundsson, Gunnar; Larsen, Guðrun

    2016-01-01

    Volcanic eruptions are common in Iceland and have caused health problems ever since the settlement of Iceland. Here we describe volcanic activity and the effects of volcanic gases and ash on human health in Iceland. Volcanic gases expelled during eruptions can be highly toxic for humans if their concentrations are high, irritating the mucus membranes of the eyes and upper respiratory tract at lower concentrations. They can also be very irritating to the skin. Volcanic ash is also irritating for the mucus membranes of the eyes and upper respiratory tract. The smalles particles of volcanic ash can reach the alveoli of the lungs. Described are four examples of volcanic eruptions that have affected the health of Icelanders. The eruption of Laki volcanic fissure in 1783-1784 is the volcanic eruption that has caused the highest mortality and had the greatest effects on the well-being of Icelanders. Despite multiple volcanic eruptions during the last decades in Iceland mortality has been low and effects on human health have been limited, although studies on longterm effects are lacking. Studies on the effects of the Eyjafjallajökul eruption in 2010 on human health showed increased physical and mental symptoms, especially in those having respiratory disorders. The Directorate of Health in Iceland and other services have responded promptly to recurrent volcanic eruptions over the last few years and given detailed instructions on how to minimize the effects on the public health. Key words: volcanic eruptions, Iceland, volcanic ash, volcanic gases, health effects, mortality. Correspondence: Gunnar Guðmundsson, ggudmund@landspitali.is.

  15. First recorded eruption of Nabro volcano, Eritrea, 2011

    Science.gov (United States)

    Goitom, Berhe; Oppenheimer, Clive; Hammond, James O. S.; Grandin, Raphaël; Barnie, Talfan; Donovan, Amy; Ogubazghi, Ghebrebrhan; Yohannes, Ermias; Kibrom, Goitom; Kendall, J.-Michael; Carn, Simon A.; Fee, David; Sealing, Christine; Keir, Derek; Ayele, Atalay; Blundy, Jon; Hamlyn, Joanna; Wright, Tim; Berhe, Seife

    2015-10-01

    We present a synthesis of diverse observations of the first recorded eruption of Nabro volcano, Eritrea, which began on 12 June 2011. While no monitoring of the volcano was in effect at the time, it has been possible to reconstruct the nature and evolution of the eruption through analysis of regional seismological and infrasound data and satellite remote sensing data, supplemented by petrological analysis of erupted products and brief field surveys. The event is notable for the comparative rarity of recorded historical eruptions in the region and of caldera systems in general, for the prodigious quantity of SO2 emitted into the atmosphere and the significant human impacts that ensued notwithstanding the low population density of the Afar region. It is also relevant in understanding the broader magmatic and tectonic significance of the volcanic massif of which Nabro forms a part and which strikes obliquely to the principal rifting directions in the Red Sea and northern Afar. The whole-rock compositions of the erupted lavas and tephra range from trachybasaltic to trachybasaltic andesite, and crystal-hosted melt inclusions contain up to 3,000 ppm of sulphur by weight. The eruption was preceded by significant seismicity, detected by regional networks of sensors and accompanied by sustained tremor. Substantial infrasound was recorded at distances of hundreds to thousands of kilometres from the vent, beginning at the onset of the eruption and continuing for weeks. Analysis of ground deformation suggests the eruption was fed by a shallow, NW-SE-trending dike, which is consistent with field and satellite observations of vent distributions. Despite lack of prior planning and preparedness for volcanic events in the country, rapid coordination of the emergency response mitigated the human costs of the eruption.

  16. Diffuse Bullous Eruptions in an Elderly Woman: Late-Onset Bullous Systemic Lupus Erythematosus

    Directory of Open Access Journals (Sweden)

    Prajwal Boddu

    2016-10-01

    Full Text Available Vesiculobullous eruptions in the elderly represent a diverse range of varying pathophysiologies and can present a significant clinical dilemma to the diagnostician. Diagnosis requires a careful review of clinical history, attention to detail on physical and histomorphological examination, and appropriate immunofluorescence testing. We describe the case of a 73-year-old female who presented to our hospital with a painful blistering skin rash developed over 2 days. Examination of the skin was remarkable for numerous flaccid hemorrhagic bullae on a normal-appearing nonerythematous skin involving both the upper and lower extremities. Histopathology of the biopsy lesion showed interface change at the epidermo-dermal region with subepidermal blister formation, mild dermal fibrosis, and sparse interstitial neutrophilic infiltrate. Immunohistological analysis was significant for positive IgG basement membrane zone antibodies with a dermal pattern of localization on direct immunofluorescence and positive IgG antinuclear antibodies on indirect immunofluorescence. Evidence of antibodies to type VII collagen suggested the diagnosis of epidermolysis bullosa acquisita versus bullous systemic lupus erythematosus (BSLE. A diagnosis of BSLE was made based on positive American College of Rheumatology criteria, acquired vesiculo-bullous eruptions with compatible histopathological and immunofluorescence findings. This case illustrates one of many difficulties a physician encounters while arriving at a diagnosis from a myriad of immunobullous dermatoses. Also, it is important for internists and dermatologists alike to be aware of and differentiate this uncommon and nonspecific cutaneous SLE manifestation from a myriad of disorders presenting with vesiculobullous skin eruptions in the elderly.

  17. Using Blogs to Promote Alternative Perspective to Volcanic Eruptions

    Science.gov (United States)

    Hamane, A.

    2011-12-01

    Distance learning is becoming more common in many higher education institutions making asynchronous online tools an essential component to promote positive student outcomes. California State University Los Angeles's online Natural Disasters course implements blogs as a collaborative constructive tool to allow students to build knowledge with their peers rather than to receive a body of facts in isolation. Blogs allow participants to post a chronological series of entries that give insight to thoughts and feelings about a specific event to a broader audience. In this course, students adopt an alternate identity and create a first-person commentary or diary entry as if they witnessed a historical volcanic event. Peers are instructed to post comments to blogs by offering sympathy, advice, solutions, or encouragement. Roleplaying between participants provides the opportunity for students to be engaged through multiple perspectives - a powerful means to understand societal impacts and to gain valuable insights. The blogging activity is devised so that novice students can complete the task on their own, yet read blog posts and comments from more capable peers. Anecdotal evidence suggests students have a greater appreciation and a deeper understanding of the impacts that volcanic eruptions have on society and the environment.

  18. Magma transport and storage at Mt. Etna (Italy): A review of geodetic and petrological data for the 2002-03, 2004 and 2006 eruptions

    Science.gov (United States)

    Palano, Mimmo; Viccaro, Marco; Zuccarello, Francesco; Gresta, Stefano

    2017-11-01

    A detailed reconstruction of magma movements within the plumbing system of Mt. Etna volcano has been made by reviewing the eruptions occurring during the October 2002-December 2006 period. The availability of continuous GPS data allowed detecting at least ten different ground deformation stages, highlighting deflationary and inflationary episodes as well as the occurrence of a shallow dike intrusion. These data have been coupled with the available petrological datasets including major/trace elements and Sr-Nd-Pb isotope compositions for the volcanic rocks erupted in the 2002-2006 period. We identified two main magmatic reservoirs located at different depths along the plumbing system of the volcano. The former is located at a depth of 7 km bsl and fed the 2001 and 2002-03 eruptions, while the latter, located from 3.5 to 5.5 km bsl, fed the 2004-05 and 2006 eruptions. Petrological characteristics of emitted products have been correlated with the inflation vs. deflation cycles related to the identified sources, providing evidence for changes through time of the evolutionary degree of the erupted magmas along with variations in their geochemical feature. Finally, we suggest that a modification of the deep plumbing system of the volcano might have occurred during the 2002-03 eruption, as a consequence of the major seaward motion of the eastern flank of the volcano.

  19. Air pressure waves from Mount St. Helens eruptions

    Science.gov (United States)

    Reed, Jack W.

    1987-10-01

    Infrasonic recordings of the pressure wave from the Mount St. Helens (MSH) eruption on May 18, 1980, together with the weather station barograph records were used to estimate an equivalent explosion airblast yield for this eruption. Pressure wave amplitudes versus distance patterns were found to be comparable with patterns found for a small-scale nuclear explosion, the Krakatoa eruption, and the Tunguska comet impact, indicating that the MSH wave came from an explosion equivalent of about 5 megatons of TNT. The peculiar audibility pattern reported, with the blast being heard only at ranges beyond about 100 km, is explained by consideration of finite-amplitude shock propagation developments.

  20. Discovery of the largest historic silicic submarine eruption

    OpenAIRE

    Carey Rebecca J.; Wysoczanski Richard J.; Wunderman Richard L.; Jutzeler Martin

    2014-01-01

    It was likely twice the size of the renowned Mount St. Helens eruption of 1980 and perhaps more than 10 times bigger than the more recent 2010 Eyjafjallajökull eruption in Iceland. However unlike those two events which dominated world news headlines in 2012 the daylong submarine silicic eruption at Havre volcano in the Kermadec Arc New Zealand (Figure 1a; 800 kilometers north of Auckland New Zealand) passed without fanfare. In fact for a while no one even knew it had occurred. © 2014 The Auth...

  1. Discovery of the Largest Historic Silicic Submarine Eruption

    Science.gov (United States)

    Carey, Rebecca J.; Wysoczanski, Richard; Wunderman, Richard; Jutzeler, Martin

    2014-05-01

    It was likely twice the size of the renowned Mount St. Helens eruption of 1980 and perhaps more than 10 times bigger than the more recent 2010 Eyjafjallajökull eruption in Iceland. However, unlike those two events, which dominated world news headlines, in 2012 the daylong submarine silicic eruption at Havre volcano in the Kermadec Arc, New Zealand (Figure 1a; ~800 kilometers north of Auckland, New Zealand), passed without fanfare. In fact, for a while no one even knew it had occurred.

  2. Management of Large Erupting Complex Odontoma in Maxilla

    Directory of Open Access Journals (Sweden)

    Colm Murphy

    2014-01-01

    Full Text Available We present the unusual case of a large complex odontoma erupting in the maxilla. Odontomas are benign developmental tumours of odontogenic origin. They are characterized by slow growth and nonaggressive behaviour. Complex odontomas, which erupt, are rare. They are usually asymptomatic and are identified on routine radiograph but may present with erosion into the oral cavity with subsequent cellulitis and facial asymmetry. This present paper describes the presentation and management of an erupting complex odontoma, occupying the maxillary sinus with extension to the infraorbital rim. We also discuss various surgical approaches used to access this anatomic area.

  3. Eruptive history of Mammoth Mountain and its mafic periphery, California

    Science.gov (United States)

    Hildreth, Wes; Fierstein, Judy

    2016-07-13

    This report and accompanying geologic map portray the eruptive history of Mammoth Mountain and a surrounding array of contemporaneous volcanic units that erupted in its near periphery. The moderately alkaline Mammoth eruptive suite, basaltic to rhyodacitic, represents a discrete new magmatic system, less than 250,000 years old, that followed decline of the subalkaline rhyolitic system active beneath adjacent Long Valley Caldera since 2.2 Ma (Hildreth, 2004). The scattered vent array of the Mammoth system, 10 by 20 km wide, is unrelated to the rangefront fault zone, and its broad nonlinear footprint ignores both Long Valley Caldera and the younger Mono-Inyo rangefront vent alignment.

  4. Mechanisms of tooth eruption and orthodontic tooth movement.

    Science.gov (United States)

    Wise, G E; King, G J

    2008-05-01

    Teeth move through alveolar bone, whether through the normal process of tooth eruption or by strains generated by orthodontic appliances. Both eruption and orthodontics accomplish this feat through similar fundamental biological processes, osteoclastogenesis and osteogenesis, but there are differences that make their mechanisms unique. A better appreciation of the molecular and cellular events that regulate osteoclastogenesis and osteogenesis in eruption and orthodontics is not only central to our understanding of how these processes occur, but also is needed for ultimate development of the means to control them. Possible future studies in these areas are also discussed, with particular emphasis on translation of fundamental knowledge to improve dental treatments.

  5. Settlement Relocation Modeling: Reacting to Merapi’s Eruption Incident

    Science.gov (United States)

    Pramitasari, A.; Buchori, I.

    2018-02-01

    Merapi eruption has made severe damages in Central Java Province. Klaten was one of the most affected area, specifically in Balerante Village. This research is made to comprehend GIS model on finding alternative locations for impacted settlement in hazardous zones of eruption. The principal objective of the research study is to identify and analyze physical condition, community characteristics, and local government regulation related to settlements relocation plan for impacted area of eruption. The output is location map which classified into four categories, i.e. not available, available with low accessibility, available with medium accessibility, and available with high accessibility.

  6. Characterization of the seismicity prior to the 2011 El Hierro eruption

    Science.gov (United States)

    Domínguez Cerdeña, Itahiza; del Fresno, Carmen; Gomis Moreno, Almudena; Hernández Yanes, Paula; Meletlidis, Stavros; López, Carmen

    2014-05-01

    The last eruption of the Canary Islands started on 10 October 2011, 2 km south of El Hierro. This submarine eruption was the first fully monitored volcanic eruption in this archipelago and was preceded by various precursory signals, the most evident of which was the seismicity that started in July 2011. This seismicity includes almost 10,000 low-magnitude earthquakes located during 81 days before the eruption which revealed a 20 km horizontal migration from the north of the island to the south at depths of between 10 and 17 km, the deeper events occurring further south. In this work we try to improve the quality of the seismic catalogue. We applied a relative location algorithm (hypoDD) to improve hypocentral locations. Tests performed to check the reliability of the results gave maximum uncertainties of 400 m in the relocations. Furthermore, new features were found, including the origin of the seismicity in the center of the island and the presence of two alternating seismogenic zones in the north of the island during the first month of activity. The first days of the unrest the seismic network was composed by only 2 seismic stations and almost no location was possible. We obtained information about location and magnitude of these events at the beginning of the seismic crisis by comparison of the waveforms by correlation with located earthquakes. We have also analyzed the baselevel seismicity of El Hierro from 1996 using digital data of a short period station. Manual revision of these data showed a considerably low number of earthquakes in the region before the unrest (less than one event per day).

  7. The prominent role of serotonergic degeneration in apathy, anxiety and depression in de novo Parkinson's disease.

    Science.gov (United States)

    Maillet, Audrey; Krack, Paul; Lhommée, Eugénie; Météreau, Elise; Klinger, Hélène; Favre, Emilie; Le Bars, Didier; Schmitt, Emmanuelle; Bichon, Amélie; Pelissier, Pierre; Fraix, Valérie; Castrioto, Anna; Sgambato-Faure, Véronique; Broussolle, Emmanuel; Tremblay, Léon; Thobois, Stéphane

    2016-09-01

    SEE SCHRAG AND POLITIS DOI101093/AWW190 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE: Apathy, which can occur separately or in combination with depression and anxiety, is one of the most frequently encountered neuropsychiatric symptoms in Parkinson's disease. Pathophysiological evidence suggests that parkinsonian apathy is primarily due to a mesolimbic dopaminergic denervation, but the role of the serotonergic alteration has never been examined, despite its well-known involvement in the pathogenesis of depression and anxiety. To fill this gap, we address here the pure model of de novo Parkinson's disease, without the confounding effects of antiparkinsonian treatment. Fifteen apathetic (Lille Apathy Rating Scale scores ≥ -21) and 15 non-apathetic (-36 ≤ Lille Apathy Rating Scale scores ≤ -22) drug-naïve de novo parkinsonian patients were enrolled in the present study and underwent detailed clinical assessment and positron emission tomography imaging, using both dopaminergic [(11)C-N-(3-iodoprop-2E-enyl)-2-beta-carbomethoxy-3-beta-(4-methylphenyl)-nortropane (PE2I)] (n = 29) and serotonergic [(11)C-N,N-dimethyl-2-(-2-amino-4-cyanophenylthio)-benzylamine (DASB)] (n = 27) presynaptic transporter radioligands. Apathetic parkinsonian patients presented higher depression (P = 0.0004) and anxiety (P = 0.004) scores - as assessed using the Beck Depression Inventory and the part B of the State-Trait Anxiety Inventory, respectively - compared to the non-apathetic ones - who were not different from the age-matched healthy subjects (n = 15). Relative to the controls, the non-apathetic parkinsonian patients mainly showed dopaminergic denervation (n = 14) within the right caudate nucleus, bilateral putamen, thalamus and pallidum, while serotonergic innervation (n = 15) was fairly preserved. Apathetic parkinsonian patients exhibited, compared to controls, combined and widespread dopaminergic (n = 15) and serotonergic (n = 12) degeneration within the bilateral caudate nuclei

  8. Solar Prominences Embedded in Flux Ropes: Morphological Features and Dynamics from 3D MHD Simulations

    Science.gov (United States)

    Terradas, J.; Soler, R.; Luna, M.; Oliver, R.; Ballester, J. L.; Wright, A. N.

    2016-04-01

    The temporal evolution of a solar prominence inserted in a three-dimensional magnetic flux rope is investigated numerically. Using the model of Titov & Démoulin under the regime of weak twist, the cold and dense prominence counteracts gravity by modifying the initially force-free magnetic configuration. In some cases a quasi-stationary situation is achieved after the relaxation phase, characterized by the excitation of standing vertical oscillations. These oscillations show a strong attenuation with time produced by the mechanism of continuum damping due to the inhomogeneous transition between the prominence and solar corona. The characteristic period of the vertical oscillations does not depend strongly on the twist of the flux rope. Nonlinearity is responsible for triggering the Kelvin-Helmholtz instability associated with the vertical oscillations and that eventually produces horizontal structures. Contrary to other configurations in which the longitudinal axis of the prominence is permeated by a perpendicular magnetic field, like in unsheared arcades, the orientation of the prominence along the flux rope axis prevents the development of Rayleigh-Taylor instabilities and therefore the appearance of vertical structuring along this axis.

  9. SOLAR PROMINENCES EMBEDDED IN FLUX ROPES: MORPHOLOGICAL FEATURES AND DYNAMICS FROM 3D MHD SIMULATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Terradas, J.; Soler, R.; Oliver, R.; Ballester, J. L. [Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Luna, M. [Instituto de Astrofsíca de Canarias, E-38205 La Laguna, Tenerife (Spain); Wright, A. N., E-mail: jaume.terradas@uib.es [School of Mathematics and Statistics, University of St Andrews, St Andrews, KY16 9SS (United Kingdom)

    2016-04-01

    The temporal evolution of a solar prominence inserted in a three-dimensional magnetic flux rope is investigated numerically. Using the model of Titov and Démoulin under the regime of weak twist, the cold and dense prominence counteracts gravity by modifying the initially force-free magnetic configuration. In some cases a quasi-stationary situation is achieved after the relaxation phase, characterized by the excitation of standing vertical oscillations. These oscillations show a strong attenuation with time produced by the mechanism of continuum damping due to the inhomogeneous transition between the prominence and solar corona. The characteristic period of the vertical oscillations does not depend strongly on the twist of the flux rope. Nonlinearity is responsible for triggering the Kelvin–Helmholtz instability associated with the vertical oscillations and that eventually produces horizontal structures. Contrary to other configurations in which the longitudinal axis of the prominence is permeated by a perpendicular magnetic field, like in unsheared arcades, the orientation of the prominence along the flux rope axis prevents the development of Rayleigh–Taylor instabilities and therefore the appearance of vertical structuring along this axis.

  10. Prominent extraaxial CSF space on cranial ultrasound in infants: correlation with neurodevelopmental outcome

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bo Kyung; Lee, Mun Hyang; Yoon, Hye Kyung; Jung, Kyung Jae; Park, Won Soon; Chang, Yun Sil; Kim, Chan Gyo [Sungkyunkwan Univ. School of Medicine, Seoul (Korea, Republic of)

    1999-08-01

    To determine the clinical significance of prominent extra-axial CSF space (EACSFS) in infants, as seen on cranial ultrasound. Between March 1996 and November 1997, all infants who had undergone head ultrasound at our institution and were found to have prominent EACSFS were evaluated. The width of the interhemispheric fissure was measured at three locations at the level of the frontal horn, body and atrium of the lateral ventricles. The depth of the CSF space over the convexity was also measured. The average of these measurements was calculated and each patient was assigned to one of three groups: mild, moderate, or marked. Ultrasound findings were evaluated for other associated abnormalities. Clinical neurodevelopment was evaluated by a pediatric neurologist, and ultrasound and neurodevelopmental findings were correlated. Prominent EACSFS was found in 153 patients, and neurodevelopmental evaluation up to a corrected age of 9 months was available in 133. One hundred and eight of 117 infants with normal neurodevelopment had no other associated abnormality(n=81), or abnormality associated only with grade I subependymal hemorrhage or cyst(n=27). Twelve of 16 infants with an abnormal neurodevelopmental outcome had major abnormalities including PVL, grade IV hemorrhage, and marked ventriculomegaly. Prominent EACSFS alone does not appear to be clinically significant. An abnormal neurodevelopmental outcome is associated with major abnormalities seen on ultrasound. Follow-up examination for prominent EACSFS is not indicated unless the associated abnormality requires further evaluations.

  11. Extrusion cycles of dome-forming eruptions

    Science.gov (United States)

    de'Michieli Vitturi, M.; Clarke, A. B.; Neri, A.; Voight, B.

    2010-12-01

    We investigated the dynamics of magma ascent along a dome-forming conduit coupled with the formation and extrusion of a degassed plug at the top by a two-phase flow model. We treated the magma mixture as a liquid continuum with dispersed gas bubbles and crystals in thermodynamic equilibrium with the melt. A modified Poiseulle form of the viscous term for fully developed laminar flow in an elliptic conduit was assumed. During ascent, magma pressure decreases and water vapor exsolves and partially degasses from the melt as the melt simultaneously crystallizes, causing changes in mixture density and viscosity, which may eventually lead to the formation of a degassed plug sealing the conduit. The numerical model DOMEFLOW (de’ Michieli Vitturi et al., EPSL 2010) has been applied to dome-building eruptions using conditions approximately appropriate for the Soufrière Hills volcano, Montserrat, which has led to a better understanding of the role of a plug on eruption periodicity. Two mechanisms, which have been proposed to cause periodicity, have been implemented in the model and their corresponding timescales explored. The first test applies a stick-slip model in which the plug is considered as solid and static/dynamic friction, as described in Iverson et al. [Nature 2006, 444, 439-43], replaces the viscous forces in the momentum equation. This mechanism yields cycle timescales of seconds to tens of seconds with values generally depending on assumed friction coefficients. Although not all constants and parameters have been explored for this model, we suggest that a stick-slip mechanism of this type cannot explain the cycles of extrusion and explosion typically observed at Montserrat (timescales of hours). The second mechanism does not consider friction but allows enhanced permeable gas loss in the shallow conduit, possibly due to connected porosity or micro- or macro-scale fractures. Enhanced permeable gas loss may lead to formation of a dense and rheologically

  12. 78 FR 69691 - Draft Guidance for Industry on Product Name Placement, Size, and Prominence in Advertising and...

    Science.gov (United States)

    2013-11-20

    ...] Draft Guidance for Industry on Product Name Placement, Size, and Prominence in Advertising and... entitled ``Product Name Placement, Size, and Prominence in Advertising and Promotional Labeling.'' When... promotional labeling and advertising for prescription human drugs, including biological drug products, and...

  13. The A.D. 1835 eruption of Volcán Cosigüina, Nicaragua: A guide for assessing local volcanic hazards

    Science.gov (United States)

    Scott, William E.; Gardner, Cynthia A.; Devoli, Graziella; Alvarez, Antonio

    2006-01-01

    the west flank of the volcano records tens of eruptions, some of which were greater in magnitude than that of 1835. Weathering evidence suggests this sequence is at least several thousand years old. The wide extent of pyroclastic flows and thick tephra fall during 1835, the greater magnitude of some previous Holocene eruptions, and the location of Cosigüina on a peninsula limit the options to reduce risk during future unrest and eruption.

  14. Impacts of the 2014-2015 Holuhraun eruption on the UK atmosphere

    Science.gov (United States)

    Twigg, Marsailidh M.; Ilyinskaya, Evgenia; Beccaceci, Sonya; Green, David C.; Jones, Matthew R.; Langford, Ben; Leeson, Sarah R.; Lingard, Justin J. N.; Pereira, Gloria M.; Carter, Heather; Poskitt, Jan; Richter, Andreas; Ritchie, Stuart; Simmons, Ivan; Smith, Ron I.; Sim Tang, Y.; Van Dijk, Netty; Vincent, Keith; Nemitz, Eiko; Vieno, Massimo; Braban, Christine F.

    2016-09-01

    Volcanic emissions, specifically from Iceland, pose a pan-European risk and are on the UK National Risk Register due to potential impacts on aviation, public health, agriculture, the environment and the economy, from both effusive and explosive activity. During the 2014-2015 fissure eruption at Holuhraun in Iceland, the UK atmosphere was significantly perturbed. This study focuses one major incursion in September 2014, affecting the surface concentrations of both aerosols and gases across the UK, with sites in Scotland experiencing the highest sulfur dioxide (SO2) concentrations. The perturbation event observed was confirmed to originate from the fissure eruption using satellite data from GOME2B and the chemical transport model, EMEP4UK, which was used to establish the spatial distribution of the plume over the UK during the event of interest. At the two UK European Monitoring and Evaluation Program (EMEP) supersite observatories (Auchencorth Moss, SE Scotland, and Harwell, SE England) significant alterations in sulfate (SO42-) content of PM10 and PM2.5 during this event, concurrently with evidence of an increase in ultrafine aerosol most likely due to nucleation and growth of aerosol within the plume, were observed. At Auchencorth Moss, higher hydrochloric acid (HCl) concentrations during the September event (max = 1.21 µg m-3, cf. annual average 0.12 µg m-3 in 2013), were assessed to be due to acid displacement of chloride (Cl-) from sea salt (NaCl) to form HCl gas rather than due to primary emissions of HCl from Holuhraun. The gas and aerosol partitioning at Auchencorth Moss of inorganic species by thermodynamic modelling confirmed the observed partitioning of HCl. Using the data from the chemical thermodynamic model, ISORROPIA-II, there is evidence that the background aerosol, which is typically basic at this site, became acidic with an estimated pH of 3.8 during the peak of the event.Volcano plume episodes were periodically observed by the majority of the UK

  15. Impacts of the 2014–2015 Holuhraun eruption on the UK atmosphere

    Directory of Open Access Journals (Sweden)

    M. M. Twigg

    2016-09-01

    Full Text Available Volcanic emissions, specifically from Iceland, pose a pan-European risk and are on the UK National Risk Register due to potential impacts on aviation, public health, agriculture, the environment and the economy, from both effusive and explosive activity. During the 2014–2015 fissure eruption at Holuhraun in Iceland, the UK atmosphere was significantly perturbed. This study focuses one major incursion in September 2014, affecting the surface concentrations of both aerosols and gases across the UK, with sites in Scotland experiencing the highest sulfur dioxide (SO2 concentrations. The perturbation event observed was confirmed to originate from the fissure eruption using satellite data from GOME2B and the chemical transport model, EMEP4UK, which was used to establish the spatial distribution of the plume over the UK during the event of interest. At the two UK European Monitoring and Evaluation Program (EMEP supersite observatories (Auchencorth Moss, SE Scotland, and Harwell, SE England significant alterations in sulfate (SO42− content of PM10 and PM2.5 during this event, concurrently with evidence of an increase in ultrafine aerosol most likely due to nucleation and growth of aerosol within the plume, were observed. At Auchencorth Moss, higher hydrochloric acid (HCl concentrations during the September event (max  =  1.21 µg m−3, cf. annual average 0.12 µg m−3 in 2013, were assessed to be due to acid displacement of chloride (Cl− from sea salt (NaCl to form HCl gas rather than due to primary emissions of HCl from Holuhraun. The gas and aerosol partitioning at Auchencorth Moss of inorganic species by thermodynamic modelling confirmed the observed partitioning of HCl. Using the data from the chemical thermodynamic model, ISORROPIA-II, there is evidence that the background aerosol, which is typically basic at this site, became acidic with an estimated pH of 3.8 during the peak of the event.Volcano plume episodes were

  16. Evolution of a small hydrothermal eruption episode through a mud pool of varying depth and rheology, White Island, NZ

    Science.gov (United States)

    Edwards, M. J.; Kennedy, B. M.; Jolly, A. D.; Scheu, B.; Jousset, P.

    2017-02-01

    , which may in turn influence the bubble burst depth. Occasionally, visible yellowing of the steam/gas plume led us to suggest that elemental sulphur may also be present in the conduit and may also play a role in regulating bubble release dynamics. Although, evidence for magmatic/phreatomagmatic eruptions was present during eruptions later in 2013, we found no evidence for juvenile magma in the January-February eruption episode described here. However, we concur with other investigators that magma was probably intruded to shallow levels and may have driven heat and gas flux. Our explanation for the correlation of pool depth, mud viscosity and eruption regime is based on a conceptual model in which a pool is perched above a two phase hydrothermal system and is sensitive to changes in the heat and gas flux from shallow magma. The variable release of gas and thermal perturbations in the course of the January-February eruptive episode impacted the pool level, the water to sediment ratio in the pool, and thus its viscosity, and in turn modulated the eruption regime. The varying degree of explosivity throughout this episode calls for a new consideration of pool properties in assessing eruption hazards at this frequently visited volcano. We additionally emphasise that ballistic hazards from small eruptions exist coupled with a range of seismic signals and that the hazard was greatest during infrasound tremor.

  17. Nuclear collapse observed during the eruption of Mt. Usu

    CERN Document Server

    Matsumoto, T A

    2002-01-01

    Mt. Usu which was located about 70 km southwest from Sapporo in Hokkaido (the north island of Japan) began to erupt on March 31 in 2000. A nuclear emulsion was placed on a foot of Mt. Usu to catch small atomic clusters which were expected to be emitted during the eruption. Curious atomic clusters and their reaction products were successfully observed on surfaces of the nuclear emulsion. By comparing them with similar products which were obtained in previous experiments of discharge and electrolysis, it was concluded that micro Ball Lightning was really emitted during the eruption of Mt. Usu and that explosive reactions by nuclear collapse could have been involved to contribute to energy of the eruption. (author)

  18. Nuclear collapse observed during the eruption of Mt. Usu

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Taka-aki [Hokkaido Univ., Dept. of Nuclear Engineering, Sapporo, Hokkaido (Japan)

    2002-09-01

    Mt. Usu which was located about 70 km southwest from Sapporo in Hokkaido (the north island of Japan) began to erupt on March 31 in 2000. A nuclear emulsion was placed on a foot of Mt. Usu to catch small atomic clusters which were expected to be emitted during the eruption. Curious atomic clusters and their reaction products were successfully observed on surfaces of the nuclear emulsion. By comparing them with similar products which were obtained in previous experiments of discharge and electrolysis, it was concluded that micro Ball Lightning was really emitted during the eruption of Mt. Usu and that explosive reactions by nuclear collapse could have been involved to contribute to energy of the eruption. (author)

  19. Three-dimensional analysis of mandibular growth and tooth eruption

    DEFF Research Database (Denmark)

    Krarup, S.; Darvann, Tron Andre; Larsen, Per

    2005-01-01

    Normal and abnormal jaw growth and tooth eruption are topics of great importance for several dental and medical disciplines. Thus far, clinical studies on these topics have used two-dimensional (2D) radiographic techniques. The purpose of the present study was to analyse normal mandibular growth...... and tooth eruption in three dimensions based on computer tomography (CT) scans, extending the principles of mandibular growth analysis proposed by Bjork in 1969 from two to three dimensions. As longitudinal CT data from normal children are not available (for ethical reasons), CT data from children......, relocated laterally during growth. Furthermore, the position of tooth buds remained relatively stable inside the jaw until root formation started. Eruption paths of canines and premolars were vertical, whereas molars erupted in a lingual direction. The 3D method would seem to offer new insight into jaw...

  20. Eruption Forecasting: Success and Surprise at Kasatochi and Okmok Volcanoes

    Science.gov (United States)

    Prejean, S.; Power, J.; Brodsky, E.

    2008-12-01

    In the summer of 2008, the Alaska Volcano Observatory (AVO) successfully forecast eruption at an unmonitored volcano, Kasatochi, and was unable to forecast eruption at a well monitored volcano, Okmok. We use these case studies to explore the limitations and opportunities of seismically monitored and unmonitored systems and to evaluate situations when we can expect to succeed and when we must expect to fail in eruption forecasting. Challenges in forecasting eruptions include interpreting seismicity in context of volcanic history, developing a firm understanding of distance scales over which pre- and co-eruptive seismic signals are observed, and improving our ability to discriminate processes causing tremor. Kasatochi Volcano is a 3 km wide island in the central Aleutian Islands with no confirmed historical activity. Little is known about the eruptive history of the volcano. It was not considered an immediate threat until 3 days prior to eruption. A report of ground shaking by a biology field crew on the island on August 4 was the first indication of unrest. On August 6 a vigorous seismic swarm became apparent on the nearest seismic stations 40 km distant. The aviation color code/volcano alert level at Kasatochi was increased to Yellow/Advisory in response to increasing magnitude and frequency of earthquakes. The color code/alert level was increased to Orange/Watch on August 7 when volcanic tremor was observed in the wake of the largest earthquake in the sequence, a M 5.6. Three hours after the onset of volcanic tremor, eruption was confirmed by satellite data and the color code/alert level increased to Red/Warning. Eruption forecasting was possible only due to the exceptionally large moment release of pre-eruptive seismicity. The key challenge in evaluating the situation was distinguishing between tectonic activity and a volcanic swarm. It is likely there were weeks to months of precursory seismicity, however little instrumental record exists due to the lack of a

  1. Formation and dynamics of a solar eruptive flux tube

    Science.gov (United States)

    Inoue, Satoshi; Kusano, Kanya; Büchner, Jörg; Skála, Jan

    2018-01-01

    Solar eruptions are well-known drivers of extreme space weather, which can greatly disturb the Earth's magnetosphere and ionosphere. The triggering process and initial dynamics of these eruptions are still an area of intense study. Here we perform a magnetohydrodynamic simulation taking into account the observed photospheric magnetic field to reveal the dynamics of a solar eruption in a real magnetic environment. In our simulation, we confirmed that tether-cutting reconnection occurring locally above the polarity inversion line creates a twisted flux tube, which is lifted into a toroidal unstable area where it loses equilibrium, destroying the force-free state, and driving the eruption. Consequently, a more highly twisted flux tube is built up during this initial phase, which can be further accelerated even when it returns to a stable area. We suggest that a nonlinear positive feedback process between the flux tube evolution and reconnection is the key to ensure this extra acceleration.

  2. Primary failure of eruption- a case report with cone beam computerized tomographic imaging.

    Science.gov (United States)

    Aruna, U; Annamalai, P R; Nayar, Sanjna; Bhuminathan, S

    2014-04-01

    Tooth eruption is an intricate and complex process which can fail to occur due to several reasons. Failure of tooth eruption in the absence of any systemic condition or any obstruction in the eruptive pathway can be attributed to lack of inherent eruptive potential of the tooth, termed as Primary Failure of Eruption (PFE). This is a rare condition and usually has a genetic etiology. Here we report a rare case in which there is Primary Failure of Eruption in the mandibular right quadrant. There is also mechanical failure of eruption of maxillary right canine and supernumerary teeth palatal to the maxillary central incisors. This association of supernumerary teeth and mechanical failure of eruption along with primary failure of eruption has not been reported so far. Proper diagnosis is very important in cases of Primary Failure of Eruption. There are several diagnostic criteria to identify these cases. Since these cases do not respond to orthodontic force, early diagnosis is of essential importance.

  3. Towards forecasting volcanic eruptions on a global scale

    Science.gov (United States)

    Hooper, A. J.; Heimisson, E. R.; Gaddes, M.; Bagnardi, M.; Sigmundsson, F.; Spaans, K.; Parks, M.; Gudmundsson, M. T.; Ebmeier, S. K.; Holohan, E. P.; Wright, T. J.; Jonsdottir, K.; Hreinsdottir, S.; Dumont, S.; Ofeigsson, B.; Vogfjord, K. S.

    2016-12-01

    Volcanic eruptions can cause loss of life, damage health, and have huge economic impacts, providing strong societal motivation for predicting eruptive behavior prior to and during eruptions. I will present here recent progress we have made in mechanical modelling with a predictive capacity, and how we are expanding volcano monitoring to a global scale. The eruption of Bardarbunga volcano, Iceland, in 2014-2015 was the largest eruption there for more than 200 years, producing 1.6 km3of lava. Prior to eruption, magma propagated almost 50 km beneath the surface, over a period of two weeks. Key questions to answer in advance of such eruptions are: will it erupt, where, how much and for how long? We developed a model based on magma taking a path that maximizes energy release, which aligns well with the actual direction taken. Our model also predicts eruption in a topographic low, as actually occurred. As magma was withdrawn, the volcano surface sagged downwards. A coupled model of magma flow and piston-like collapse predicts a declining magma flow rate and ground subsidence rate, in accordance with that observed. With such a model, observations can be used to predict the timescale and rates of eruption, even before one starts. The primary data needed to constrain these predictive models are measurements of surface deformation. In Iceland, this is achieved using high accuracy GPS, however, most volcanoes have no ground instrumentation. A recent ESA mission, Sentinel-1, can potentially image deformation at almost all subaerial volcanoes every 6 days, using a technique called interferometric synthetic aperture radar (InSAR). This will allow us to detect early stages of magma migration at any volcano, then task other satellites to acquire data at a higher rate. We are working on a system to process all Sentinel-1 data in near-real time, which is a big data challenge. We have also developed new algorithms that maximize signal extraction from each new acquisition and

  4. The Chaitén rhyolite lava dome: Eruption sequence, lava dome volumes, rapid effusion rates and source of the rhyolite magma

    Science.gov (United States)

    Pallister, John S.; Diefenbach, Angela K.; Burton, William C.; Munoz, Jorge; Griswold, Julia P.; Lara, Luis E.; Lowenstern, Jacob B.; Valenzuela, Carolina E.

    2013-01-01

    We use geologic field mapping and sampling, photogrammetric analysis of oblique aerial photographs, and digital elevation models to document the 2008-2009 eruptive sequence at Chaitén Volcano and to estimate volumes and effusion rates for the lava dome. We also present geochemical and petrologic data that contribute to understanding the source of the rhyolite and its unusually rapid effusion rates. The eruption consisted of five major phases: 1. An explosive phase (1-11 May 2008); 2. A transitional phase (11-31 May 2008) in which low-altitude tephra columns and simultaneous lava extrusion took place; 3. An exogenous lava flow phase (June-September 2008); 4. A spine extrusion and endogenous growth phase (October 2008-February 2009); and 5. A mainly endogenous growth phase that began after the collapse of a prominent Peléean spine on 19 February 2009 and continued until the end of the eruption (late 2009 or possibly earliest 2010). The 2008-2009 rhyolite lava dome has a total volume of approximately 0.8 km3. The effusion rate averaged 66 m3s-1 during the first two weeks and averaged 45 m3s-1 for the first four months of the eruption, during which 0.5 km3 of rhyolite lava was erupted. These are among the highest rates measured world-wide for historical eruptions of silicic lava. Chaitén’s 2008-2009 lava is phenocryst-poor obsidian and microcrystalline rhyolite with 75.3±0.3% SiO2. The lava was erupted at relatively high temperature and is remarkably similar in composition and petrography to Chaitén’s pre-historic rhyolite. The rhyolite’s normative composition plots close to that of low pressure (100-200 MPa) minimum melts in the granite system, consistent with estimates of approximately 5 to 10 km source depths based on phase equilibria and geodetic studies. Calcic plagioclase, magnesian orthopyroxene and aluminous amphibole among the sparse phenocrysts suggest derivation of the rhyolite by melt extraction from a more mafic magmatic mush. High temperature

  5. SYNTHETIC HYDROGEN SPECTRA OF OSCILLATING PROMINENCE SLABS IMMERSED IN THE SOLAR CORONA

    Energy Technology Data Exchange (ETDEWEB)

    Zapiór, M.; Heinzel, P. [Astronomical Institute, The Czech Academy of Sciences, 25165 Ondřejov, The Czech Republic (Czech Republic); Oliver, R.; Ballester, J. L. [Universitat de les Illes Balears. Cra. de Valldemossa, km 7.5. Palma (Illes Balears), E-07122 (Spain)

    2016-08-20

    We study the behavior of H α and H β spectral lines and their spectral indicators in an oscillating solar prominence slab surrounded by the solar corona, using an MHD model combined with a 1D radiative transfer code taken in the line of sight perpendicular to the slab. We calculate the time variation of the Doppler shift, half-width, and maximum intensity of the H α and H β spectral lines for different modes of oscillation. We find a non-sinusoidal time dependence of some spectral parameters with time. Because H α and H β spectral indicators have different behavior for different modes, caused by differing optical depths of formation and different plasma parameter variations in time and along the slab, they may be used for prominence seismology, especially to derive the internal velocity field in prominences.

  6. Subcision Using a Spinal Needle Cannula and a Thread for Prominent Nasolabial Fold Correction

    Directory of Open Access Journals (Sweden)

    Sang-Yeul Lee

    2013-05-01

    Full Text Available Deepening of the nasolabial crease is an esthetically unpleasing aging phenomenon occurring in the midface. Various treatment modalities have been introduced to improve the appearance of prominent nasolabial folds, all of which have pros and cons. Currently, a minimally invasive technique using synthetic dermal fillers is most commonly used. A simple and easy subcision procedure using a wire scalpel has also been used and reported to be effective for prominent nasolabial fold correction, with minimal complications. As an alternative to the wire scalpel, we used a 20-gauge metal type spinal needle cannula (Hakko Co. and 4-0 Vicryl suture (Ethicon Inc. for subcision of nasolabial folds. This technique is less expensive than the use of a wire scalpel and easily available when needed. Therefore, on the basis of favorable results, our modified subcision technique may be considered effective for prominent nasolabial fold correction.

  7. The EU and Climate Change Policy: Law, Politics and Prominence at Different Levels

    Directory of Open Access Journals (Sweden)

    Chad David Damro

    2008-11-01

    Full Text Available The European Union (EU is a prominent player in the politics of climate change, operating as an authoritative regional actor that influences policy-making at the national and international levels. The EU’s climate change policies are thus subjected to multiple pressures that arise from the domestic politics of its twenty-seven individual member states and the international politics of non-EU states with which it negotiates. Facing these multiple pressures, how and why could such a non-traditional actor develop into a prominent player at different levels of climate change policy-making? This article argues that the EU’s rise to prominence can be understood by tracking a number of historical-legal institutional developments at the domestic and international levels. The article also provides a preliminary investigation of the EU emissions trading scheme, a new institutional mechanism that illustrates the policy pressures arising from different levels.

  8. CONTRACTING AND ERUPTING COMPONENTS OF SIGMOIDAL ACTIVE REGIONS

    International Nuclear Information System (INIS)

    Liu Rui; Wang Yuming; Liu Chang; Wang Haimin; Török, Tibor

    2012-01-01

    It has recently been noted that solar eruptions can be associated with the contraction of coronal loops that are not involved in magnetic reconnection processes. In this paper, we investigate five coronal eruptions originating from four sigmoidal active regions, using high-cadence, high-resolution narrowband EUV images obtained by the Solar Dynamic Observatory (SDO). The magnitudes of the flares associated with the eruptions range from GOES class B to class X. Owing to the high-sensitivity and broad temperature coverage of the Atmospheric Imaging Assembly (AIA) on board SDO, we are able to identify both the contracting and erupting components of the eruptions: the former is observed in cold AIA channels as the contracting coronal loops overlying the elbows of the sigmoid, and the latter is preferentially observed in warm/hot AIA channels as an expanding bubble originating from the center of the sigmoid. The initiation of eruption always precedes the contraction, and in the energetically mild events (B- and C-flares), it also precedes the increase in GOES soft X-ray fluxes. In the more energetic events, the eruption is simultaneous with the impulsive phase of the nonthermal hard X-ray emission. These observations confirm that loop contraction is an integrated process in eruptions with partially opened arcades. The consequence of contraction is a new equilibrium with reduced magnetic energy, as the contracting loops never regain their original positions. The contracting process is a direct consequence of flare energy release, as evidenced by the strong correlation of the maximal contracting speed, and strong anti-correlation of the time delay of contraction relative to expansion, with the peak soft X-ray flux. This is also implied by the relationship between contraction and expansion, i.e., their timing and speed.

  9. How to predict timing of eruption of inferior second premolars

    OpenAIRE

    Lima, Eduardo Martinelli Santayana de; Schmidt, Caroline Bom; Araujo, Laura Lütz; Rizzatto, Susana Maria Deon; Lima, Fernando Martinelli de

    2012-01-01

    Objective: To evaluate the relationship between the stages of dental formation and the timing of eruption of mandibular second premolars. Materials and Methods: The sample comprised panoramic radiographs of 25 children, 7 to 12 years old, observed by space supervision during development of dentition. The initial radiograph (T1) was taken in the mixed dentition period and the progress radiograph (T2) close to the eruption of mandibular second premolars. The stages of dental formation were dete...

  10. Injections of osteoprotegerin and PMA delay tooth eruption.

    Science.gov (United States)