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Sample records for madrid seismic zone

  1. Seismological investigation of earthquakes in the New Madrid Seismic Zone

    International Nuclear Information System (INIS)

    Herrmann, R.B.; Nguyen, B.

    1993-08-01

    Earthquake activity in the New Madrid Seismic Zone had been monitored by regional seismic networks since 1975. During this time period, over 3,700 earthquakes have been located within the region bounded by latitudes 35 degrees--39 degrees N and longitudes 87 degrees--92 degrees W. Most of these earthquakes occur within a 1.5 degrees x 2 degrees zone centered on the Missouri Bootheel. Source parameters of larger earthquakes in the zone and in eastern North America are determined using surface-wave spectral amplitudes and broadband waveforms for the purpose of determining the focal mechanism, source depth and seismic moment. Waveform modeling of broadband data is shown to be a powerful tool in defining these source parameters when used complementary with regional seismic network data, and in addition, in verifying the correctness of previously published focal mechanism solutions

  2. Earthquake Hazard in the New Madrid Seismic Zone Remains a Concern

    Science.gov (United States)

    Frankel, A.D.; Applegate, D.; Tuttle, M.P.; Williams, R.A.

    2009-01-01

    There is broad agreement in the scientific community that a continuing concern exists for a major destructive earthquake in the New Madrid seismic zone. Many structures in Memphis, Tenn., St. Louis, Mo., and other communities in the central Mississippi River Valley region are vulnerable and at risk from severe ground shaking. This assessment is based on decades of research on New Madrid earthquakes and related phenomena by dozens of Federal, university, State, and consulting earth scientists. Considerable interest has developed recently from media reports that the New Madrid seismic zone may be shutting down. These reports stem from published research using global positioning system (GPS) instruments with results of geodetic measurements of strain in the Earth's crust. Because of a lack of measurable strain at the surface in some areas of the seismic zone over the past 14 years, arguments have been advanced that there is no buildup of stress at depth within the New Madrid seismic zone and that the zone may no longer pose a significant hazard. As part of the consensus-building process used to develop the national seismic hazard maps, the U.S. Geological Survey (USGS) convened a workshop of experts in 2006 to evaluate the latest findings in earthquake hazards in the Eastern United States. These experts considered the GPS data from New Madrid available at that time that also showed little to no ground movement at the surface. The experts did not find the GPS data to be a convincing reason to lower the assessment of earthquake hazard in the New Madrid region, especially in light of the many other types of data that are used to construct the hazard assessment, several of which are described here.

  3. Seismic Readings from the Deepest Borehole in the New Madrid Seismic Zone

    Energy Technology Data Exchange (ETDEWEB)

    Woolery, Edward W [KY Geological Survey, Univ of KY; Wang, Zhenming [KY Geological Survey, Univ of KY; Sturchio, Neil C [Dept of earth and Env. Sciences, Univ of Ill at Chicago

    2006-03-01

    Since the 1980s, the research associated with the UK network has been primarily strong-motion seismology of engineering interest. Currently the University of Kentucky operates a strong-motion network of nine stations in the New Madrid Seismic Zone. A unique feature of the network is the inclusions of vertical strong-motion arrays, each with one or two downhole accelerometers. The deepest borehole array is 260 m below the surfaces at station VASA in Fulton County, Kentucky. A preliminary surface seismic refraction survey was conducted at the site before drilling the hole at VSAS (Woolery and Wang, 2002). The depth to the Paleozoic bedrock at the site was estimated to be approximately 595 m, and the depth to the first very stiff layer (i.e. Porters Creek Clay) was found to be about 260 m. These depths and stratigraphic interpretation correlated well with a proprietary seismic reflection line and the Ken-Ten Oil Exploration No. 1 Sanger hole (Schwalb, 1969), as well as our experience in the area (Street et al., 1995; Woolery et al., 1999).

  4. Studying geodesy and earthquake hazard in and around the New Madrid Seismic Zone

    Science.gov (United States)

    Boyd, Oliver Salz; Magistrale, Harold

    2011-01-01

    Workshop on New Madrid Geodesy and the Challenges of Understanding Intraplate Earthquakes; Norwood, Massachusetts, 4 March 2011 Twenty-six researchers gathered for a workshop sponsored by the U.S. Geological Survey (USGS) and FM Global to discuss geodesy in and around the New Madrid seismic zone (NMSZ) and its relation to earthquake hazards. The group addressed the challenge of reconciling current geodetic measurements, which show low present-day surface strain rates, with paleoseismic evidence of recent, relatively frequent, major earthquakes in the region. The workshop presentations and conclusions will be available in a forthcoming USGS open-file report (http://pubs.usgs.gov).

  5. Stress development in heterogenetic lithosphere: Insights into earthquake processes in the New Madrid Seismic Zone

    Science.gov (United States)

    Zhan, Yan; Hou, Guiting; Kusky, Timothy; Gregg, Patricia M.

    2016-03-01

    The New Madrid Seismic Zone (NMSZ) in the Midwestern United States was the site of several major M 6.8-8 earthquakes in 1811-1812, and remains seismically active. Although this region has been investigated extensively, the ultimate controls on earthquake initiation and the duration of the seismicity remain unclear. In this study, we develop a finite element model for the Central United States to conduct a series of numerical experiments with the goal of determining the impact of heterogeneity in the upper crust, the lower crust, and the mantle on earthquake nucleation and rupture processes. Regional seismic tomography data (CITE) are utilized to infer the viscosity structure of the lithosphere which provide an important input to the numerical models. Results indicate that when differential stresses build in the Central United States, the stresses accumulating beneath the Reelfoot Rift in the NMSZ are highly concentrated, whereas the stresses below the geologically similar Midcontinent Rift System are comparatively low. The numerical observations coincide with the observed distribution of seismicity throughout the region. By comparing the numerical results with three reference models, we argue that an extensive mantle low velocity zone beneath the NMSZ produces differential stress localization in the layers above. Furthermore, the relatively strong crust in this region, exhibited by high seismic velocities, enables the elevated stress to extend to the base of the ancient rift system, reactivating fossil rifting faults and therefore triggering earthquakes. These results show that, if boundary displacements are significant, the NMSZ is able to localize tectonic stresses, which may be released when faults close to failure are triggered by external processes such as melting of the Laurentide ice sheet or rapid river incision.

  6. Cooperative New Madrid seismic network

    International Nuclear Information System (INIS)

    Herrmann, R.B.; Johnston, A.C.

    1990-01-01

    The development and installation of components of a U.S. National Seismic Network (USNSN) in the eastern United States provides the basis for long term monitoring of eastern earthquakes. While the broad geographical extent of this network provides a uniform monitoring threshold for the purpose of identifying and locating earthquakes and while it will provide excellent data for defining some seismic source parameters for larger earthquakes through the use of waveform modeling techniques, such as depth and focal mechanism, by itself it will not be able to define the scaling of high frequency ground motions since it will not focus on any of the major seismic zones in the eastern U.S. Realizing this need and making use of a one time availability of funds for studying New Madrid earthquakes, Saint Louis University and Memphis State University successfully competed for funding in a special USGS RFP for New Madrid studies. The purpose of the proposal is to upgrade the present seismic networks run by these institutions in order to focus on defining the seismotectonics and ground motion scaling in the New Madrid Seismic Zone. The proposed network is designed both to complement the U.S. National Seismic Network and to make use of the capabilities of the communication links of that network

  7. Late Pleistocene and Holocene paleoseismology of an intraplate seismic zone in a large alluvial valley, the New Madrid seismic zone, Central USA

    Science.gov (United States)

    Guccione, Margaret J.

    2005-10-01

    The New Madrid seismic zone (NMSZ) is an intraplate right-lateral strike-slip and thrust fault system contained mostly within the Mississippi Alluvial Valley. The most recent earthquake sequence in the zone occurred in 1811 1812 and had estimated moment magnitudes of 7 8 (e.g., [Johnston, A.C., 1996. Seismic moment assessment of stable continental earthquakes, Part 3: 1811 1812 New Madrid, 1886 Charleston, and 1755 Lisbon. Geophysical Journal International 126, 314 344; Johnston, A.C., Schweig III, E.S, 1996. The enigma of the New Madrid earthquakes of 1811 1812. Annual Reviews of Earth and Planetary Sciences 24, 339 384; Hough, S.E., Armbruster, J.G., Seeber, L., Hough, J.F., 2000. On the modified Mercalli intensities and magnitudes of the New Madrid earthquakes. Journal of Geophysical Research 105 (B10), 23,839 23,864; Tuttle, M.P., 2001. The use of liquefaction features in paleoseismology: Lessons learned in the New Madrid seismic zone, central United States. Journal of Seismology 5, 361 380]). Four earlier prehistoric earthquakes or earthquake sequences have been dated A.D. 1450 ± 150, 900 ± 100, 300 ± 200, and 2350 B.C. ± 200 years using paleoliquefaction features, particularly those associated with native American artifacts, and in some cases surface deformation ([Craven, J. A. 1995. Paleoseismology study in the New Madrid seismic zone using geological and archeological features to constrain ages of liquefaction deposits. M.S thesis, University of Memphis, Memphis, TN, U.S.A.; Tuttle, M.P., Lafferty III, R.H., Guccione, M.J., Schweig III, E.S., Lopinot, N., Cande, R., Dyer-Williams, K., Haynes, M., 1996. Use of archaeology to date liquefaction features and seismic events in the New Madrid seismic zone, central United States. Geoarchaeology 11, 451 480; Guccione, M.J., Mueller, K., Champion, J., Shepherd, S., Odhiambo, B., 2002b. Stream response to repeated co-seismic folding, Tiptonville dome, western Tennessee. Geomorphology 43(2002), 313 349; Tuttle, M

  8. Recordings from the deepest borehole in the New Madrid Seismic Zone

    Science.gov (United States)

    Wang, Z.; Woolery, E.W.

    2006-01-01

    The recordings at the deepest vertical strong-motion array (VSAS) from three small events, the 21 October 2004 Tiptonville, Tennessee, earthquake; the 10 February 2005 Arkansas earthquake; and the 2 June 2005 Ridgely, Tennessee, earthquake show some interesting wave-propagation phenomena through the soils: the S-wave is attenuated from 260 m to 30 m depth and amplified from 30 m to the surface. The S-wave arrival times from the three events yielded different shear-wave velocity estimates for the soils. These different estimates may be the result of different incident angles of the S-waves due to different epicentral distances. The epicentral distances are about 22 km, 110 km, and 47 km for the Tiptonville, Arkansas, and Ridgely earthquakes, respectively. These recordings show the usefulness of the borehole strong-motion array. The vertical strong-motion arrays operated by the University of Kentucky have started to accumulate recordings that will provide a database for scientists and engineers to study the effects of the near-surface soils on the strong ground motion in the New Madrid Seismic Zone. More information about the Kentucky Seismic and Strong-Motion Network can be found at www.uky.edu/KGS/geologichazards. The digital recordings are available at ftp://kgsweb.uky.edu.

  9. Types of damage that could result from a great earthquake in the New Madrid, Missouri, seismic zone

    Science.gov (United States)

    Hopper, M.G.; Algermissen, S.T.

    1984-01-01

    In the winter of 1811–1812 a series of three great earthquakes occurred in the New Madrid seismic zone. In addition to the three principal shocks, at least 15 other earthquakes, Io ≥ VIII, occurred within a year of the first large earthquake on December 16, 1811. The three main shocks were felt over the entire eastern United States. They were strong enough to cause minor damage as far away as Indiana and Ohio on the north, the Carolinas on the east, and southern Mississippi on the south. They were strong enough to cause severe or structural damage in parts of Missouri, Illinois, Indiana, Kentucky, Tennessee, Mississippi, and Arkansas. The section of this poster titled "Seismic history of the New Madrid region" describes what happened in the epicentral region. Fortunately, few people lived in the severely shaken area in 1811; that is not the case today. What would happen if a series of earthquakes as large and numerous as the "New Madrid" earthquakes were to occur in the New Madrid seismic zone today?

  10. Variable post-Paleozoic deformation detected by seismic reflection profiling across the northwestern "prong" of New Madrid seismic zone

    Science.gov (United States)

    McBride, J.H.; Pugin, Andre J.M.; Nelson, W.J.; Larson, T.H.; Sargent, S.L.; Devera, J.A.; Denny, F.B.; Woolery, E.W.

    2003-01-01

    High-resolution shallow seismic reflection profiles across the northwesternmost part of the New Madrid seismic zone (NMSZ) and northwestern margin of the Reelfoot rift, near the confluence of the Ohio and Mississippi Rivers in the northern Mississippi embayment, reveal intense structural deformation that apparently took place during the late Paleozoic and/or Mesozoic up to near the end of the Cretaceous Period. The seismic profiles were sited on both sides of the northeast-trending Olmsted fault, defined by varying elevations of the top of Mississippian (locally base of Cretaceous) bedrock. The trend of this fault is close to and parallel with an unusually straight segment of the Ohio River and is approximately on trend with the westernmost of two groups of northeast-aligned epicenters ("prongs") in the NMSZ. Initially suspected on the basis of pre-existing borehole data, the deformation along the fault has been confirmed by four seismic reflection profiles, combined with some new information from drilling. The new data reveal (1) many high-angle normal and reverse faults expressed as narrow grabens and anticlines (suggesting both extensional and compressional regimes) that involved the largest displacements during the late Cretaceous (McNairy); (2) a different style of deformation involving probably more horizontal displacements (i.e., thrusting) that occurred at the end of this phase near the end of McNairy deposition, with some fault offsets of Paleocene and younger units; (3) zones of steeply dipping faults that bound chaotic blocks similar to that observed previously from the nearby Commerce geophysical lineament (CGL); and (4) complex internal deformation stratigraphically restricted to the McNairy, suggestive of major sediment liquefaction or landsliding. Our results thus confirm the prevalence of complex Cretaceous deformations continuing up into Tertiary strata near the northern terminus of the NMSZ. ?? 2003 Elsevier Science B.V. All rights reserved.

  11. Instrument Correction and Dynamic Site Profile Validation at the Central United States Seismic Observatory, New Madrid Seismic Zone

    Science.gov (United States)

    Brengman, C.; Woolery, E. W.; Wang, Z.; Carpenter, S.

    2016-12-01

    The Central United States Seismic Observatory (CUSSO) is a vertical seismic array located in southwestern Kentucky within the New Madrid seismic zone. It is intended to describe the effects of local geology, including thick sediment overburden, on seismic-wave propagation, particularly strong-motion. The three-borehole array at CUSSO is composed of seismic sensors placed on the surface, and in the bedrock at various depths within the 585 m thick sediment overburden. The array's deep borehole provided a unique opportunity in the northern Mississippi embayment for the direct geological description and geophysical measurement of the complete late Cretaceous-Quaternary sediment column. A seven layer, intra-sediment velocity model is interpreted from the complex, inhomogeneous stratigraphy. The S- and P-wave sediment velocities range between 160 and 875 m/s and between 1000 and 2300 m/s, respectively, with bedrock velocities of 1452 and 3775 m/s, respectively. Cross-correlation and direct comparisons were used to filter out the instrument response and determine the instrument orientation, making CUSSO data ready for analysis, and making CUSSO a viable calibration site for other free-field sensors in the area. The corrected bedrock motions were numerically propagated through the CUSSO soil profile (transfer function) and compared, in terms of both peak acceleration and amplitude spectra, to the recorded surface observations. Initial observations reveal a complex spectral mix of amplification and de-amplification across the array, indicating the site effect in this deep sediment setting is not simply generated by the shallowest layers.

  12. Comparing the New Madrid Seismic Zone with the Osning Thrust: implications for GIA-induced intraplate tectonics in northern Germany

    Science.gov (United States)

    Brandes, Christian; Steffen, Holger; Wu, Patrick; Tanner, David; Winsemann, Jutta

    2013-04-01

    Continental intraplate tectonics is a widespread phenomenon that causes significant earthquakes. These earthquakes even occur in areas that are characterized by low strain rates and there are often long intervals between the individual seismic events (Gangopadhyay & Talwani, 2003) that result in a hazard potential. To better understand the controlling factors of intraplate plate earthquakes in northern Germany, we compare the Osning Thrust with the intensively-studied New Madrid Seismic Zone in the Midwest USA. Both areas share major similarities such as a failed rift-basin setting, the presence of intrusive magmatic bodies in the subsurface, tectonic reactivation during the Late Cretaceous, paleo- and historic seismicity and comparable fault parameters. In addition, both areas have a very similar Late Pleistocene deglaciation history. New Madrid was c. 340 km south of the Laurentide ice sheet and ice retreat started around 21 ka and was completed by 8.5 ka (Grollimund & Zoback, 2001). The Osning Thrust was c. 310 km south of the Scandinavian ice sheet and deglaciation began at 24 ka. Both areas show historic seismicity in a similar time frame (New Madrid Seismic Zone: 1811-1812, Johnston & Schweig, 1996); Osning Thrust: 1612 and 1767, Grünthal & Bosse, 1997). We use numerical simulations to identify the timing of potentially GIA-induced fault activity, which are based on the fault stability margin concept of Wu & Hasegawa (1996). From our modelling results it is evident that the fault stability margin changed to negative between 16 and 13 ka for the Osning Thrust, which matches the OSL data of fault-related growth strata (Brandes et al., 2012). For the New Madrid Seismic Zone, the fault stability margin becomes zero between 2.5 ka BP (before 1812) to about 2 ka after the 1812 event, depending on the parameters of the model. This indicates that for both seismic zones, seismicity due to deglaciation was and still is very likely. From this study it can be derived

  13. Near-source attenuation of high-frequency body waves beneath the New Madrid Seismic Zone

    Science.gov (United States)

    Pezeshk, Shahram; Sedaghati, Farhad; Nazemi, Nima

    2018-03-01

    Attenuation characteristics in the New Madrid Seismic Zone (NMSZ) are estimated from 157 local seismograph recordings out of 46 earthquakes of 2.6 ≤ M ≤ 4.1 with hypocentral distances up to 60 km and focal depths down to 25 km. Digital waveform seismograms were obtained from local earthquakes in the NMSZ recorded by the Center for Earthquake Research and Information (CERI) at the University of Memphis. Using the coda normalization method, we tried to determine Q values and geometrical spreading exponents at 13 center frequencies. The scatter of the data and trade-off between the geometrical spreading and the quality factor did not allow us to simultaneously derive both these parameters from inversion. Assuming 1/ R 1.0 as the geometrical spreading function in the NMSZ, the Q P and Q S estimates increase with increasing frequency from 354 and 426 at 4 Hz to 729 and 1091 at 24 Hz, respectively. Fitting a power law equation to the Q estimates, we found the attenuation models for the P waves and S waves in the frequency range of 4 to 24 Hz as Q P = (115.80 ± 1.36) f (0.495 ± 0.129) and Q S = (161.34 ± 1.73) f (0.613 ± 0.067), respectively. We did not consider Q estimates from the coda normalization method for frequencies less than 4 Hz in the regression analysis since the decay of coda amplitude was not observed at most bandpass filtered seismograms for these frequencies. Q S/ Q P > 1, for 4 ≤ f ≤ 24 Hz as well as strong intrinsic attenuation, suggest that the crust beneath the NMSZ is partially fluid-saturated. Further, high scattering attenuation indicates the presence of a high level of small-scale heterogeneities inside the crust in this region.

  14. 20 cool facts about the New Madrid Seismic Zone-Commemorating the bicentennial of the New Madrid earthquake sequence, December 1811-February 1812 [poster

    Science.gov (United States)

    Williams, R.A.; McCallister, N.S.; Dart, R.L.

    2011-01-01

    This poster summarizes a few of the more significant facts about the series of large earthquakes that struck the New Madrid seismic zone of southeastern Missouri, northeastern Arkansas, and adjacent parts of Tennessee and Kentucky from December 1811 to February 1812. Three earthquakes in this sequence had a magnitude (M) of 7.0 or greater. The first earthquake occurred on December 16, 1811, at 2:15 a.m.; the second on January 23, 1812, at 9 a.m.; and the third on February 7, 1812, at 3:45 a.m. These three earthquakes were among the largest to strike North America since European settlement. The mainshocks were followed by many hundreds of aftershocks that occurred over the next decade. Many of the aftershocks were major earthquakes themselves. The area that was strongly shaken by the three main shocks was 2-3 times as large as the strongly shaken area of the 1964 M9.2 Alaskan earthquake and 10 times as large as that of the 1906 M7.8 San Francisco earthquake. Geologic studies show that the 1811-1812 sequence was not an isolated event in the New Madrid region. The 1811-1812 New Madrid earthquake sequence was preceded by at least two other similar sequences in about A.D. 1450 and A.D. 900. Research also indicates that other large earthquakes have occurred in the region surrounding the main New Madrid seismicity trends in the past 5,000 years or so.

  15. Toward a consistent model for strain accrual and release for the New Madrid Seismic Zone, central United States

    Science.gov (United States)

    Hough, S.E.; Page, M.

    2011-01-01

    At the heart of the conundrum of seismogenesis in the New Madrid Seismic Zone is the apparently substantial discrepancy between low strain rate and high recent seismic moment release. In this study we revisit the magnitudes of the four principal 1811–1812 earthquakes using intensity values determined from individual assessments from four experts. Using these values and the grid search method of Bakun and Wentworth (1997), we estimate magnitudes around 7.0 for all four events, values that are significantly lower than previously published magnitude estimates based on macroseismic intensities. We further show that the strain rate predicted from postglacial rebound is sufficient to produce a sequence with the moment release of one Mmax6.8 every 500 years, a rate that is much lower than previous estimates of late Holocene moment release. However, Mw6.8 is at the low end of the uncertainty range inferred from analysis of intensities for the largest 1811–1812 event. We show that Mw6.8 is also a reasonable value for the largest main shock given a plausible rupture scenario. One can also construct a range of consistent models that permit a somewhat higher Mmax, with a longer average recurrence rate. It is thus possible to reconcile predicted strain and seismic moment release rates with alternative models: one in which 1811–1812 sequences occur every 500 years, with the largest events being Mmax∼6.8, or one in which sequences occur, on average, less frequently, with Mmax of ∼7.0. Both models predict that the late Holocene rate of activity will continue for the next few to 10 thousand years.

  16. Deformation of "stable" continental interiors by mantle convection: Implications for intraplate stress in the New Madrid Seismic Zone

    Science.gov (United States)

    Forte, A. M.; Moucha, R.; Simmons, N. A.; Grand, S. P.; Mitrovica, J. X.

    2011-12-01

    The enigmatic origin of large-magnitude earthquakes far from active plate boundaries, especially those occurring in so-called "stable" continental interiors, is a source of continuing controversy that has eluded a satisfactory explanation using past geophysical models of intraplate deformation and faulting. One outstanding case of such major intraplate earthquakes is the 1811-1812 series of events in the New Madrid Seismic Zone (NMSZ). We contend that the origin of some of these enigmatic intraplate events is due to regional variations in the pattern of tectonic stress generated by mantle convective flow acting on the overlying lithosphere and crust. Mantle convection affects the entire surface of the planet, irrespective of the current configuration of surface plate boundaries. In addition, it must be appreciated that plate tectonics is not a 2-D process, because the convective flow that drives the observed horizontal motions of the tectonic plates also drives vertical displacements of the crust across distances as great as 2 to 3 km. This dynamic topography is directly correlated with convection-driven stress field variations in the crust and lithosphere and these stresses can be locally focussed if the mantle rheology below the lithosphere is characterised by sufficiently low viscosities. We have developed global models of convection-driven mantle flow [Forte et al. 2009,2010] that are based on recent high-resolution 3-D tomography models derived from joint inversions of seismic, geodynamic and mineral physics data [Simmons et al. 2007,2008,2010]. These tomography-based mantle convection models also include a full suite of surface geodynamic (postglacial rebound and convection) constraints on the depth-dependent average viscosity of the mantle [Mitrovica & Forte 2004]. Our latest tomography-based and geodynamically-constrained convection calculations reveal that mantle flow under the central US are driven by density anomalies within the lower mantle associated

  17. Effects of a significant New Madrid Seismic Zone event on oil and natural gas pipelines and their cascading effects to critical infrastructures

    Science.gov (United States)

    Fields, Damon E.

    Critical Infrastructure Protection (CIP) is a construct that relates preparedness and responsiveness to natural or man-made disasters that involve vulnerable assets deemed essential for the functioning of our economy and society. Infrastructure systems (power grids, bridges, airports, etc.) are vulnerable to disastrous types of events--natural or man-made. Failures of these systems can have devastating effects on communities and entire regions. CIP relates our willingness, ability, and capability to defend, mitigate, and re-constitute those assets that succumb to disasters affecting one or more infrastructure sectors. This qualitative research utilized ethnography and employed interviews with subject matter experts (SMEs) from various fields of study regarding CIP with respect to oil and natural gas pipelines in the New Madrid Seismic Zone. The study focused on the research question: What can be done to mitigate vulnerabilities in the oil and natural gas infrastructures, along with the potential cascading effects to interdependent systems, associated with a New Madrid fault event? The researcher also analyzed National Level Exercises (NLE) and real world events, and associated After Action Reports (AAR) and Lessons Learned (LL) in order to place a holistic lens across all infrastructures and their dependencies and interdependencies. Three main themes related to the research question emerged: (a) preparedness, (b) mitigation, and (c) impacts. These themes comprised several dimensions: (a) redundancy, (b) node hardening, (c) education, (d) infrastructure damage, (e) cascading effects, (f) interdependencies, (g) exercises, and (h) earthquake readiness. As themes and dimensions are analyzed, they are considered against findings in AARs and LL from previous real world events and large scale exercise events for validation or rejection.

  18. Anomalous radon emanation at local and regional distances preceding earthquakes in the New Madrid seismic zone and adjacent areas of the central mid-continent of North America

    International Nuclear Information System (INIS)

    Steele, S.R.

    1984-01-01

    Anomalous soil-radon activity, including several spike-like surges over periods of 5, 2, and 2 1/2 months, and a year-long declining trend, preceded the most significant earthquakes of the central mid-continental region of North America during 1981 and early 1984. The observations of these events provide further evidence of (a) the existence of soil-radon anomalies precursory to the larger earthquakes in this intraplate region, (b) the utility of such anomalies in anticipating events of small to moderate magnitudes for the region, and (c) the occurrence of regional-scale strain events prior to some of the larger mid-continental earthquakes. A very recent radon anomaly, the strongest yet to be detected in the seven years of monitoring in the mid-continental region, occurred in the New Madrid seismic zone from mid-February through mid-June 1984. A 4.0 earthquake occurred one month after a peak in the radon activity. The amplitude and duration of the anomaly suggest that a significant change in the state of stress or strain may have occurred in the mid-continental region during 1984. (Auth.)

  19. Commerce geophysical lineament - Its source, geometry, and relation to the Reelfoot rift and New Madrid seismic zone

    Science.gov (United States)

    Langenheim, V.E.; Hildenbrand, T.G.

    1997-01-01

    The Commerce geophysical lineament is a northeast-trending magnetic and gravity feature that extends from central Arkansas to southern Illinois over a distance of ???400 km. It is parallel to the trend of the Reelfoot graben, but offset ???40 km to the northwest of the western margin of the rift floor. Modeling indicates that the source of the aeromagnetic and gravity anomalies is probably a mafic dike swarm. The age of the source of the Commerce geophysical lineament is not known, but the linearity and trend of the anomalies suggest a relationship with the Reelfoot rift, which has undergone episodic igneous activity. The Commerce geophysical lineament coincides with several topographic lineaments, movement on associated faults at least as young as Quaternary, and intrusions of various ages. Several earthquakes (Mb > 3) coincide with the Commerce geophysical lineament, but the diversity of associated focal mechanisms and the variety of surface structural features along the length of the Commerce geophysical lineament obscure its relation to the release of present-day strain. With the available seismicity data, it is difficult to attribute individual earthquakes to a specific structural lineament such as the Commerce geophysical lineament. However, the close correspondence between Quaternary faulting and present-day seismicity along the Commerce geophysical lineament is intriguing and warrants further study.

  20. France's seismic zoning

    International Nuclear Information System (INIS)

    Mohammadioun, B.

    1997-01-01

    In order to assess the seismic hazard in France in relation to nuclear plant siting, the CEA, EDF and the BRGM (Mine and Geology Bureau) have carried out a collaboration which resulted in a seismic-tectonic map of France and a data base on seismic history (SIRENE). These studies were completed with a seismic-tectonic zoning, taking into account a very long period of time, that enabled a probabilistic evaluation of the seismic hazard in France, and that may be related to adjacent country hazard maps

  1. Seismic sequences in the Sombrero Seismic Zone

    Science.gov (United States)

    Pulliam, J.; Huerfano, V. A.; ten Brink, U.; von Hillebrandt, C.

    2007-05-01

    The northeastern Caribbean, in the vicinity of Puerto Rico and the Virgin Islands, has a long and well-documented history of devastating earthquakes and tsunamis, including major events in 1670, 1787, 1867, 1916, 1918, and 1943. Recently, seismicity has been concentrated to the north and west of the British Virgin Islands, in the region referred to as the Sombrero Seismic Zone by the Puerto Rico Seismic Network (PRSN). In the combined seismicity catalog maintained by the PRSN, several hundred small to moderate magnitude events can be found in this region prior to 2006. However, beginning in 2006 and continuing to the present, the rate of seismicity in the Sombrero suddenly increased, and a new locus of activity developed to the east of the previous location. Accurate estimates of seismic hazard, and the tsunamigenic potential of seismic events, depend on an accurate and comprehensive understanding of how strain is being accommodated in this corner region. Are faults locked and accumulating strain for release in a major event? Or is strain being released via slip over a diffuse system of faults? A careful analysis of seismicity patterns in the Sombrero region has the potential to both identify faults and modes of failure, provided the aggregation scheme is tuned to properly identify related events. To this end, we experimented with a scheme to identify seismic sequences based on physical and temporal proximity, under the assumptions that (a) events occur on related fault systems as stress is refocused by immediately previous events and (b) such 'stress waves' die out with time, so that two events that occur on the same system within a relatively short time window can be said to have a similar 'trigger' in ways that two nearby events that occurred years apart cannot. Patterns that emerge from the identification, temporal sequence, and refined locations of such sequences of events carry information about stress accommodation that is obscured by large clouds of

  2. Delineation of seismic source zones based on seismicity parameters ...

    Indian Academy of Sciences (India)

    In the present study, an attempt has been made to delineate seismic source zones in the study area (south India) based on the seismicity parameters. Seismicity parameters and the maximum probable earthquake for these source zones were evaluated and were used in the hazard evaluation. The probabilistic evaluation of ...

  3. Delineation of seismic source zones based on seismicity parameters ...

    Indian Academy of Sciences (India)

    these source zones were evaluated and were used in the hazard evaluation. ... seismic sources, linear and areal, were considered in the present study to model the seismic sources in the ..... taken as an authentic reference manual for iden-.

  4. Madrid

    Science.gov (United States)

    2001-01-01

    This ASTER image was acquired on July 5, 2000 and covers an area of 25 by 24 km over Madrid, Spain. A historic capital city, Madrid is renowned for its unique charm and its exhilarating cultural life. In the 10th century, a Moorish fortress called Magerit was first built on the site, a plateau 656 meters (2,150 feet) above sea level. Spanish Christians seized the city a century later, although Madrid remained relatively unimportant until 1561. It was then that the Spanish king Philip II chose it as the national capital, largely because of its geographic location in the very heart of the country. Some historic structures from this and later periods still grace the narrow streets of the old section of Madrid, although the Spanish Civil War exacted a heavy toll on the city. The image is located at 40.4 degrees north latitude and 3.7 degrees west longitude. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  5. Integrated seismic interpretation of the Carlsberg Fault zone, Copenhagen, Denmark

    DEFF Research Database (Denmark)

    Nielsen, Lars; Thybo, Hans; Jørgensen, Mette Iwanouw

    2005-01-01

    the fault zone. The fault zone is a shadow zone to shots detonated outside the fault zone. Finite-difference wavefield modelling supports the interpretations of the fan recordings. Our fan recording approach facilitates cost-efficient mapping of fault zones in densely urbanized areas where seismic normal......We locate the concealed Carlsberg Fault zone along a 12-km-long trace in the Copenhagen city centre by seismic refraction, reflection and fan profiling. The Carlsberg Fault is located in a NNW-SSE striking fault system in the border zone between the Danish Basin and the Baltic Shield. Recent...... earthquakes indicate that this area is tectonically active. A seismic refraction study across the Carlsberg Fault shows that the fault zone is a low-velocity zone and marks a change in seismic velocity structure. A normal incidence reflection seismic section shows a coincident flower-like structure. We have...

  6. Definition of Exclusion Zones Using Seismic Data

    Science.gov (United States)

    Bartal, Y.; Villagran, M.; Ben Horin, Y.; Leonard, G.; Joswig, M.

    - In verifying compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT), there is a motivation to be effective, efficient and economical and to prevent abuse of the right to conduct an On-site Inspection (OSI) in the territory of a challenged State Party. In particular, it is in the interest of a State Party to avoid irrelevant search in specific areas. In this study we propose several techniques to determine `exclusion zones', which are defined as areas where an event could not have possibly occurred. All techniques are based on simple ideas of arrival time differences between seismic stations and thus are less prone to modeling errors compared to standard event location methods. The techniques proposed are: angular sector exclusion based on a tripartite micro array, half-space exclusion based on a station pair, and closed area exclusion based on circumferential networks.

  7. What controls intermediate depth seismicity in subduction zones?

    Science.gov (United States)

    Florez, M. A.; Prieto, G. A.

    2017-12-01

    Intermediate depth earthquakes seem to cluster in two distinct planes of seismicity along the subducting slab, known as Double Seismic Zones (DSZ). Precise double difference relocations in Tohoku, Japan and northern Chile confirm this pattern with striking accuracy. Furthermore, past studies have used statistical tests on the EHB global seismicity catalog to suggest that DSZs might be a dominant global feature. However, typical uncertainties associated with hypocentral depth prevent us from drawing meaningful conclusions about the detailed structure of intermediate depth seismicity and its relationship to the physical and chemical environment of most subduction zones. We have recently proposed a relative earthquake relocation algorithm based on the precise picking of the P and pP phase arrivals using array processing techniques [Florez and Prieto, 2017]. We use it to relocate seismicity in 24 carefully constructed slab segments that sample every subduction zone in the world. In all of the segments we are able to precisely delineate the structure of the double seismic zone. Our results indicate that whenever the lower plane of seismicity is active enough the width of the DSZ decreases in the down dip direction; the two planes merge at depths between 140 km and 300 km. We develop a method to unambiguously pick the depth of this merging point, the end of the DSZ, which appears to be correlated with the slab thermal parameter. We also confirm that the width of the DSZ increases with plate age. Finally, we estimate b-values for the upper and lower planes of seismicity and explore their relationships to the physical parameters that control slab subduction.

  8. Tourism in Conflict Zones. The Promotion of Spanish Civil War Heritage in the Community of Madrid

    Directory of Open Access Journals (Sweden)

    Oscar Navajas Corral

    2017-05-01

    Full Text Available For more than a decade, the processes of patrimonialization of spaces and cultural assets of the Spanish Civil War have been strengthened. The Community of Madrid has not been, and is not, alien to this process. Since the creation of the Grupo de Estudios del Frente de Madrid (GEFREMA in 2002, associations whose objective is to investigate this historical period and its material legacy, research, and patrimonialisation processes in the region have continued to increase. Arganda del Rey, Morata de Tajuña, Guadarrama, Buitrago de Lozoya, Madrid, etc., are some of the places where heritage is already available to citizens and is offered as a tourist resource. This article presents an investigation that analyzes the different spaces of the Spanish Civil War that have recovered in the region of Madrid. Based on the museological theories, which provides the communication and interpretation of the heritage, and the methodologies for the collection of quantitative and qualitative data, we have evaluated the different places in which this heritage has been valued in order to be able to Define its main variables and also be able to build proposals for its future and for future interventions elsewhere.

  9. Imaging the West Bohemia Seismic Zone

    Science.gov (United States)

    Alexandrakis, C.; Calo, M.; Bouchaala, F.; Vavrycuk, V.

    2013-12-01

    West Bohemia is located at the suture of three mantle lithosphere plates, the Eger Rift, the Cheb basin and is the site of Quaternary volcanism. This complex tectonic setting results in localized, periodic earthquake swarms throughout the region and many CO2 springs and gas exhalation sites. Nový Kostel, the most active swarm area, experiences frequent swarms of several hundreds to thousands of earthquakes over a period of weeks to several months. It is a unique study area, since the swarm region is surrounded by the West Bohemia Seismic Network (WEBNET), providing observations in all directions. Larger swarms, such as those in 1985/1986, 1997, 2000, 2007 and 2008, have been studied in terms of source mechanisms and swarm characteristics (Fischer and Michálek, 2003; Fischer et al., 2010; Vavryčuk, 2011). The seismicity is always located in the same area and depth range (6-15 km), however the active fault planes differ. This indicates changes to the local stress field, and may relate to the complicated tectonic situation and/or migrating fluids. Many studies have examined individual swarms and compared the earthquake episodes, however the mechanisms behind the phenomenon are still not understood. This has motivated many studies, including recent proposals for a reflection seismic profile directly over the swarm area and multidisciplinary monitoring through ICDP. In this study, we image the velocity structure within and around the swarm area using double-difference tomography (Zhang and Thurber, 2003) and Weighted Average Model (WAM) post-processing analysis (Calò et al., 2011). The WAM analysis averages together velocity models calculated with a variety of reasonable starting parameters. The velocities are weighted by the raypath proximity and density at an inversion node. This reduces starting model bias and artifacts, and yields a weighted standard deviation at each grid point. Earthquake locations and WEBNET P and S arrival times for the two most recent large

  10. Time-reversibility in seismic sequences: Application to the seismicity of Mexican subduction zone

    Science.gov (United States)

    Telesca, L.; Flores-Márquez, E. L.; Ramírez-Rojas, A.

    2018-02-01

    In this paper we investigate the time-reversibility of series associated with the seismicity of five seismic areas of the subduction zone beneath the Southwest Pacific Mexican coast, applying the horizontal visibility graph method to the series of earthquake magnitudes, interevent times, interdistances and magnitude increments. We applied the Kullback-Leibler divergence D that is a metric for quantifying the degree of time-irreversibility in time series. Our findings suggest that among the five seismic areas, Jalisco-Colima is characterized by time-reversibility in all the four seismic series. Our results are consistent with the peculiar seismo-tectonic characteristics of Jalisco-Colima, which is the closest to the Middle American Trench and belongs to the Mexican volcanic arc.

  11. Seismic qualification of a commercial grade emergency diesel generator system in high seismic zones

    International Nuclear Information System (INIS)

    Khan, Mohsin R.; Chen, Wayne W.H.; Chu, Winnie S.

    2004-01-01

    The paper presents the seismic qualification of a commercially procured emergency diesel generator (EDG) system for use in a nuclear power plant. Response spectrum analyses of finite element models, validated using in situ vibration test data, were performed to qualify the skid and floor mounted mechanical components whose functional capacity and structural integrity can be analyzed. Time history analyses of these models were also performed to obtain the amplified response spectra for seismic testing of small valves, electrical and electro-mechanical components whose functional capacity can not be analyzed to establish the seismic qualification. The operational loads were obtained by in-plant vibration monitoring. Full scale shake table testing was performed for auxiliary electrical cabinets. It is concluded that with some minor structural modifications, a commercial grade EDG system can be qualified for safety-related applications in nuclear power plants located in high seismic zones. (author)

  12. DEFORMATION WAVES AS A TRIGGER MECHANISM OF SEISMIC ACTIVITY IN SEISMIC ZONES OF THE CONTINENTAL LITHOSPHERE

    Directory of Open Access Journals (Sweden)

    S. I. Sherman

    2013-01-01

    Full Text Available Deformation waves as a trigger mechanism of seismic activity and migration of earthquake foci have been under discussion by researchers in seismology and geodynamics for over 50 years. Four sections of this article present available principal data on impacts of wave processes on seismicity and new data. The first section reviews analytical and experimental studies aimed at identification of relationships between wave processes in the lithosphere and seismic activity manifested as space-and-time migration of individual earthquake foci or clusters of earthquakes. It is concluded that with a systematic approach, instead of using a variety of terms to denote waves that trigger seismic process in the lithosphere, it is reasonable to apply the concise definition of ‘deformation waves’, which is most often used in fact.The second section contains a description of deformation waves considered as the trigger mechanism of seismic activity. It is concluded that a variety of methods are applied to identify deformation waves, and such methods are based on various research methods and concepts that naturally differ in sensitivity concerning detection of waves and/or impact of the waves on seismic process. Epicenters of strong earthquakes are grouped into specific linear or arc-shaped systems, which common criterion is the same time interval of the occurrence of events under analysis. On site the systems compose zones with similar time sequences, which correspond to the physical notion of moving waves (Fig. 9. Periods of manifestation of such waves are estimated as millions of years, and a direct consideration of the presence of waves and wave parameters is highly challenging. In the current state-of-the-art, geodynamics and seismology cannot provide any other solution yet.The third section presents a solution considering record of deformation waves in the lithosphere. With account of the fact that all the earthquakes with М≥3.0 are associated with

  13. Risk-Informed Selection of Steel Connections for Seismic Zones

    Directory of Open Access Journals (Sweden)

    De León-Escobedo D.

    2011-04-01

    Full Text Available The findings about the fragile behavior of steel welded connections after the Northridge 1994 earthquake, specially for frames designed to withstand lateral force, has brought an amount of new attention to the design and safety issues of the welded connections for structures located on seismic zones. In México, practitioners and designers are wondering about the seismic effectiveness of the several kinds of connections as used in steel structures. A decision must be made to balance the safety required with the costs incurred after exceeding the serviceability limit state. Structural reliability techniques provide the proper framework to include the inherent uncertainties into the design process. Registered motions after the 1985 Mexico City earthquake are properly scaled according to the seismic hazard curve for soft soil in Mexico City. Earthquake occurrence is modeled as a Poisson process and the expected life-cycle cost is taken as the decision criteria. Parametric analyses allow the identification of dominant variables and ranges where one option is more recommendable than the other one. The proposed formulation may support designers and builders for the decision making process about the selection of the convenient connection type for the seismic zones with soft soil in Mexico City.

  14. Seismic qualification of multiple interconnected safety-related cabinets in a high seismic zone

    International Nuclear Information System (INIS)

    Khan, M.R.; Chen, W.H.W.; Wang, T.Y.

    1993-01-01

    Certain safety-related multiple, interconnected electrical cabinets and the devices contained therein are required to perform their intended safety functions during and after a design basis seismic event. In general, seismic testing is performed to ensure the structural integrity of the cabinets and the functionality of their associated devices. Constrained by the shake table capacity, seismic testing is usually performed only for a limited number of interconnected cabinets. Also, original shake table tests performed usually did not provide detailed response information at various locations inside the cabinets. For operational and maintenance purposes, doors and panels of some cabinets may need to be opened while the adjacent cabinets are required to remain functional. In addition, in-cabinet response spectra need to be generated for the seismic qualification of new devices and the replacement parts. Consequently, seismic analysis of safety-related multiple, interconnected cabinets is frequently required for configurations which are different from the original tested conditions. This paper presents results of seismic tests of three interconnected safety-related cabinets and finite element analyses performed to compare the analytical results with those obtained from the cabinet seismic tests. Parametric analyses are performed to determine how many panels and doors can be opened while the adjacent cabinets still remain functional. The study indicates that for cabinets located in a high seismic zone, the critical damping of the cabinet is significantly higher than 5% to 7% typically used in qualifying electrical equipment. For devices mounted on the cabinet doors to performed their intended safety function, it requires stiffening of doors and that these doors be properly bolted to the cabinet frame. It also shows that even though doors and panels bolted to the cabinet frame are the primary seismic resistant element of the cabinet, opening of a limited number of them

  15. Double seismic zone for deep earthquakes in the izu-bonin subduction zone.

    Science.gov (United States)

    Iidaka, T; Furukawa, Y

    1994-02-25

    A double seismic zone for deep earthquakes was found in the Izu-Bonin region. An analysis of SP-converted phases confirms that the deep seismic zone consists of two layers separated by approximately 20 kilometers. Numerical modeling of the thermal structure implies that the hypocenters are located along isotherms of 500 degrees to 550 degrees C, which is consistent with the hypothesis that deep earthquakes result from the phase transition of metastable olivine to a high-pressure phase in the subducting slab.

  16. Seismic interpretation of the triangle zone at Jumping Pound, Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Slotboom, R. T. [Amerada Hess Canada Ltd., Calgary, AB (Canada); Lawton, D. C.; Spratt, D. A. [Calgary Univ., AB (Canada). Dept. of Geology and Geophysics

    1996-06-01

    The triangle zone at Jumping Point, Alberta was characterized using seismic survey data as a NW-SE-trending antiformal stack of thrust sheets involving Cretaceous rocks that have been wedged into the foreland between two detachments. Three major thrust sheets of Lower and Upper Cretaceous strata have been stacked to form the main extremity of the wedge. The structure is tightly folded at Jumping Point, and broadens northwest along the strike. 13 refs., 8 figs.

  17. Seismicity and Tectonics of the West Kaibab Fault Zone, AZ

    Science.gov (United States)

    Wilgus, J. T.; Brumbaugh, D. S.

    2014-12-01

    The West Kaibab Fault Zone (WKFZ) is the westernmost bounding structure of the Kaibab Plateau of northern Arizona. The WKFZ is a branching complex of high angle, normal faults downthrown to the west. There are three main faults within the WKFZ, the Big Springs fault with a maximum of 165 m offset, the Muav fault with 350 m of displacement, and the North Road fault having a maximum throw of approximately 90 m. Mapping of geologically recent surface deposits at or crossing the fault contacts indicates that the faults are likely Quaternary with the most recent offsets occurring one of the most seismically active areas in Arizona and lies within the Northern Arizona Seismic Belt (NASB), which stretches across northern Arizona trending NW-SE. The data set for this study includes 156 well documented events with the largest being a M5.75 in 1959 and including a swarm of seven earthquakes in 2012. The seismic data set (1934-2014) reveals that seismic activity clusters in two regions within the study area, the Fredonia cluster located in the NW corner of the study area and the Kaibab cluster located in the south central portion of the study area. The fault plane solutions to date indicate NE-SW to EW extension is occurring in the study area. Source relationships between earthquakes and faults within the WKFZ have not previously been studied in detail. The goal of this study is to use the seismic data set, the available data on faults, and the regional physiography to search for source relationships for the seismicity. Analysis includes source parameters of the earthquake data (location, depth, and fault plane solutions), and comparison of this output to the known faults and areal physiographic framework to indicate any active faults of the WKFZ, or suggested active unmapped faults. This research contributes to a better understanding of the present nature of the WKFZ and the NASB as well.

  18. Seismic cycle feedbacks in a mid-crustal shear zone

    Science.gov (United States)

    Melosh, Benjamin L.; Rowe, Christie D.; Gerbi, Christopher; Smit, Louis; Macey, Paul

    2018-07-01

    Mid-crustal fault rheology is controlled by alternating brittle and plastic deformation mechanisms, which cause feedback cycles that influence earthquake behavior. Detailed mapping and microstructural observations in the Pofadder Shear Zone (Namibia and South Africa) reveal a lithologically heterogeneous shear zone core with quartz-rich mylonites and ultramylonites, plastically overprinted pseudotachylyte and active shear folds. We present evidence for a positive feedback cycle in which coseismic grain size reduction facilitates active shear folding by enhancing competency contrasts and promoting crystal plastic flow. Shear folding strengthens a portion of a shear zone by limb rotation, focusing deformation and promoting plastic flow or brittle slip in resulting areas of localized high stress. Using quartz paleopiezometry, we estimate strain and slip rates consistent with other studies of exhumed shear zones and modern plate boundary faults, helping establish the Pofadder Shear Zone as an ancient analogue to modern, continental-scale, strike-slip faults. This feedback cycle influences seismicity patterns at the scale of study (10s of meters) and possibly larger scales as well, and contributes to bulk strengthening of the brittle-plastic transition on modern plate boundary faults.

  19. Long Term Seismic Observation in Mariana by OBSs : Double Seismic Zone and Upper Mantle Structure

    Science.gov (United States)

    Shiobara, H.; Sugioka, H.; Mochizuki, K.; Oki, S.; Kanazawa, T.; Fukao, Y.; Suyehiro, K.

    2005-12-01

    In order to obtain the deep arc structural image of Mariana, a large-scale seismic observation by using 58 long-term ocean bottom seismometers (LTOBS) had been performed from June 2003 until April 2004, which is a part of the MARGINS program funded by the NSF. Prior to this observation, a pilot long-term seismic array observation was conducted in the same area by using 10 LTOBSs from Oct. 2001 until Feb. 2003. At that time, 8 LTOBSs were recovered but one had no data. Recently, 2 LTOBSs, had troubles in the releasing, were recovered by the manned submersible (Shinkai 6500, Jamstec) for the research of the malfunction in July 2005. By using all 9 LTOBS's data, those are about 11 months long, hypocenter determination was performed and more than 3000 local events were found. Even with the 1D velocity structure based on the iasp91 model, double seismic zones and a systematic shift of epicenters between the PDE and this study were observed. To investigate the detail of hypocenter distribution and the 3D velocity structure, the DD inversion (tomoDD: Zhang and Thurber, 2003) was applied for this data set with the 1D structure initial model except for the crust, which has been surveyed by using a dense airgun-OBS system (Takahashi et al., 2003). The result of relocated hypocenters shows clear double seismic zones until about 200 km depth, a high activity area around the fore-arc serpentine sea-mount, the Big Blue, and a lined focuses along the current ridge axis in the back-arc basin, and the result of the tomography shows a image of subducting slab and a low-Vs region below the same sea-mount mentioned. The wedge mantle structure was not clearly resolved due to the inadequate source-receiver coverage, which will be done in the recent experiment.

  20. Deep mantle seismic heterogeneities in Western Pacific subduction zones

    Science.gov (United States)

    Bentham, H. L. M.; Rost, S.

    2012-04-01

    In recent years array seismology has been used extensively to image the small scale (~10 km) structure of the Earth. In the mantle, small scale structure likely represents chemical heterogeneity and is essential in our understanding of mantle convection and especially mantle mixing. As subduction is the main source of introducing crustal material into the Earth's mantle, it is of particular interest to track the transport of subducted crust through the mantle to resolve details of composition and deformation of the crust during the subduction process. Improved knowledge of subduction can help provide constraints on the mechanical mixing process of crustal material into the ambient mantle, as well as constraining mantle composition and convection. This study uses seismic array techniques to map seismic heterogeneities associated with Western Pacific subduction zones, where a variety of slab geometries have been previously observed. We use seismic energy arriving prior to PP, a P-wave underside reflection off the Earth's surface halfway between source and receiver, to probe the mantle for small-scale heterogeneities. PP precursors were analysed at Eielson Array (ILAR), Alaska using the recently developed Toolkit for Out-of-Plane Coherent Arrival Tracking (TOPCAT) algorithm. The approach combines the calculated optimal beampower and an independent semblance (coherency) measure, to improve the signal-to-noise ratio of coherent arrivals. 94 earthquakes with sufficient coherent precursory energy were selected and directivity information of the arrivals (i.e. slowness and backazimuth) was extracted from the data. The scattering locations for 311 out-of-plane precursors were determined by ray-tracing and minimising the slowness, backazimuth and differential travel time misfit. Initial analyses show that deep scattering (>1000 km) occurs beneath the Izu-Bonin subduction zone, suggesting that subducted crust does continue into the lower mantle in this location. Other

  1. Advanced criteria of seismic zoning and synthetic seismograms

    International Nuclear Information System (INIS)

    Panza, G.F.; Vaccari, F.

    1993-04-01

    A brief revision of the traditional deterministic and probabilistic methods of first order seismic zonation, outlining their limits and possibilities, indicates that they can only lead to a kind of ''post-event'' zonation, which has a limited local validity. The strong influence of laterial heterogeneities and of source properties on the spatial distribution of Peak Ground Acceleration (PGA) and of the Total Energy of ground motion (W), indicates that the traditional methods require a deep revision. The method we have developed and applied to a first-order seismic zoning of the whole Italian territory and to the microzoning of specific objects, being based on the computation of synthetic seismograms, makes it possible and necessary to take source and propagation effects into account, fully utilizing the large amount of geological and geotechnical data, already available. Even though it falls in the domain of deterministic approaches, the method is very suitable for inclusion in the definition of new integrated procedures which combine probabilistic and deterministic approaches and allow us to minimize the present drawbacks which characterise the two methods when they are considered separately. If the seismotectonic regime is well known, a very important practical aspect of our deterministic approach is the immediate capability to direct the rescue intervention of the Civil Defence where the greatest damage is expected, by drawing post-event synthetic isoseismals for the source regions. Detailed modelling of ground motion for realistic two-dimensional media is a low-cost but very powerful tool for the prevention aspects of Civil Defence since it allows the computation of realistic seismic input for important structures based on the definition of a wide set of possible scenarios, which can be immediately used in the design of new seismo-resistant constructions and in the reinforcement of existing structures. (author). 65 refs, 14 figs

  2. Seismic Structure of Mantle Transition Zone beneath Northwest Pacific Subduction Zone and its Dynamic Implication

    Science.gov (United States)

    Li, J.; Guo, G.; WANG, X.; Chen, Q.

    2017-12-01

    The northwest Pacific subduction region is an ideal location to study the interaction between the subducting slab and upper mantle discontinuities. Various and complex geometry of the Pacific subducting slab can be well traced downward from the Kuril, Japan and Izu-Bonin trench using seismicity and tomography images (Fukao and Obayashi, 2013). Due to the sparse distribution of seismic stations in the sea, investigation of the deep mantle structure beneath the broad sea regions is very limited. In this study, we applied the well- developed multiple-ScS reverberations method (Wang et al., 2017) to analyze waveforms recorded by the Chinese Regional Seismic Network, the densely distributed temporary seismic array stations installed in east Asia. A map of the topography of the upper mantle discontinuities beneath the broad oceanic regions in northwest Pacific subduction zone is imaged. We also applied the receiver function analysis to waveforms recorded by stations in northeast China and obtain the detailed topography map beneath east Asia continental regions. We then combine the two kinds of topography of upper mantle discontinuities beneath oceanic and continental regions respectively, which are obtained from totally different methods. A careful image matching and spatial correlation is made in the overlapping study regions to calibrate results with different resolution. This is the first time to show systematically a complete view of the topography of the 410-km and 660-km discontinuities beneath the east Asia "Big mantle wedge" (Zhao and Ohtani, 2009) covering the broad oceanic and continental regions in the Northwestern Pacific Subduction zone. Topography pattern of the 660 and 410 is obtained and discussed. Especially we discovered a broad depression of the 410-km discontinuity covering more than 1000 km in lateral, which seems abnormal in the cold subducting tectonic environment. Based on plate tectonic reconstruction studies and HTHP mineral experiments, we

  3. Seismic source zone characterization for the seismic hazard assessment project PEGASOS by the Expert Group 2 (EG1b)

    International Nuclear Information System (INIS)

    Burkhard, M.; Gruenthal, G.

    2009-01-01

    A comprehensive study of the seismic hazard related to the four NNP sites in NW Switzerland was performed within the project PEGASOS. To account for the epistemic uncertainties involved in the process of the characterization of seismic source zones in the frame of probabilistic seismic hazard assessments, four different expert teams have developed and defended their models in the frame of an intensive elicitation process. Here, the results of one out of four expert groups are presented. The model of this team is based first of all on considerations regarding the large scale tectonics in the context of the Alpine collision, and neotectonic constraints for defining seismic source zones. This leads to a large scale subdivision based on the structural 'architectural' considerations with little input from the present seismicity. Each of the eight large zones was characterized by the style of present-day faulting, fault orientation, and hypo central depth distribution. A further subdivision of the larger zones is performed based on information provided by the seismicity patterns. 58 small source zones have been defined in this way, each of them characterized by the available tectonic constrains, as well as the pros and cons of different existing geologic views connected to them. Of special concern in this respect were the discussion regarding thin skinned vs. thick skinned tectonics, the tectonic origin of the 1356 Basel earthquake, the role of the Permo-Carboniferous graben structures, and finally the seismogenic orientation of faults with respect to the recent crustal stress field. The uncertainties connected to the delimitations of the small source zones have been handled in form of their regrouping, formalized by the logic tree technique. The maximum magnitudes were estimated as discretized probability distribution functions. After de-clustering the used ECOS earthquake catalogue and an analysis of data completeness as a function of time the parameters of the

  4. Seismo-thermo-mechanical modeling of subduction zone seismicity

    Energy Technology Data Exchange (ETDEWEB)

    Dinther van, Y.

    2013-07-01

    The catastrophic occurrence of the 2004 M9.2 Sumatra and 2011 M9.0 Tohoku earthquakes illustrated the disastrous impact of megathrust earthquakes on society. They also emphasized our limited understanding of where and when these 'big ones' may strike. The necessary improvement of long-term seismic hazard assessment requires a better physical understanding of the seismic cycle at these seismically active subduction zones. Models have the potential to overcome the restricted, direct observations in space and time. Currently, however, no model exists to explore the relation between long-term subduction dynamics and relating deformation and short-term seismogenesis. The development, validation and initial application of such a physically consistent seismo-thermo-mechanical numerical model is the main objective of this thesis. First, I present a novel analog modeling tool that simulates cycling of megathrust earthquakes in a visco-elastic gelatin wedge. A comparison with natural observations shows interseismic and coseismic physics are captured in a robust, albeit simplified, way. This tool is used to validate that a continuum-mechanics based, visco-elasto-plastic numerical approach, typically used for large-scale geodynamic problems, can be extended to study the short-term seismogenesis of megathrust earthquakes. To generate frictional instabilities and match laboratory source parameters, a local invariant implementation of a strongly slip rate-dependent friction formulation is required. The resulting continuum approach captures several interesting dynamic features, including inter-, co- and postseismic deformation that agrees qualitatively with GPS measurements and dynamic rupture features, including cracks, self-healing pulses and fault re-rupturing. To facilitate a comparison to natural settings, I consider a more realistic setup of the Southern Chilean margin in terms of geometry and physical processes. Results agree with seismological, geodetic and

  5. Seismo-thermo-mechanical modeling of subduction zone seismicity

    International Nuclear Information System (INIS)

    Dinther van, Y.

    2013-01-01

    The catastrophic occurrence of the 2004 M9.2 Sumatra and 2011 M9.0 Tohoku earthquakes illustrated the disastrous impact of megathrust earthquakes on society. They also emphasized our limited understanding of where and when these 'big ones' may strike. The necessary improvement of long-term seismic hazard assessment requires a better physical understanding of the seismic cycle at these seismically active subduction zones. Models have the potential to overcome the restricted, direct observations in space and time. Currently, however, no model exists to explore the relation between long-term subduction dynamics and relating deformation and short-term seismogenesis. The development, validation and initial application of such a physically consistent seismo-thermo-mechanical numerical model is the main objective of this thesis. First, I present a novel analog modeling tool that simulates cycling of megathrust earthquakes in a visco-elastic gelatin wedge. A comparison with natural observations shows interseismic and coseismic physics are captured in a robust, albeit simplified, way. This tool is used to validate that a continuum-mechanics based, visco-elasto-plastic numerical approach, typically used for large-scale geodynamic problems, can be extended to study the short-term seismogenesis of megathrust earthquakes. To generate frictional instabilities and match laboratory source parameters, a local invariant implementation of a strongly slip rate-dependent friction formulation is required. The resulting continuum approach captures several interesting dynamic features, including inter-, co- and postseismic deformation that agrees qualitatively with GPS measurements and dynamic rupture features, including cracks, self-healing pulses and fault re-rupturing. To facilitate a comparison to natural settings, I consider a more realistic setup of the Southern Chilean margin in terms of geometry and physical processes. Results agree with seismological, geodetic and geological

  6. Study of the evolution of the seismic cycle of stress and strain associated to the El Salvador Fault Zone

    OpenAIRE

    Staller Vázquez, Alejandra

    2011-01-01

    • Central America: – Regional studies in Central America (Seismic Hazard). – El Salvador Fault Zone (ESFZ). – Aguacaliente‐Navarro Fault Zone (ANFZ), Central Valley of Costa Rica. – Haiti (seismic hazard) • Spain: – Regional‐Nacional studies of seismic hazards (applications to building codes, eurocode, emergency plans, etc.) – Betic range zone, south of Spain. – Ibero‐Maghrebi region (collision zone)

  7. Preliminary seismic evaluation and ranking of bridges on and over the parkways in Western Kentucky.

    Science.gov (United States)

    2008-06-01

    Five parkways in Western Kentucky are located in the region that is greatly influenced by the New Madrid and Wabash Valley Seismic Zones. This report executes a preliminary screening process, known also as the Seismic Rating System, for bridges on an...

  8. Prediction of subsurface fracture in mining zone of Papua using passive seismic tomography based on Fresnel zone

    Energy Technology Data Exchange (ETDEWEB)

    Setiadi, Herlan; Nurhandoko, Bagus Endar B.; Wely, Woen [WISFIR Lab., Physics of Complex System, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Bandung 40132 (Indonesia); Riyanto, Erwin [PT Freeport Indonesia, Tembagapura, Indonesia herlansetiadi@yahoo.com (Indonesia)

    2015-04-16

    Fracture prediction in a block cave of underground mine is very important to monitor the structure of the fracture that can be harmful to the mining activities. Many methods can be used to obtain such information, such as TDR (Time Domain Relectometry) and open hole. Both of them have limitations in range measurement. Passive seismic tomography is one of the subsurface imaging method. It has advantage in terms of measurements, cost, and rich of rock physical information. This passive seismic tomography studies using Fresnel zone to model the wavepath by using frequency parameter. Fresnel zone was developed by Nurhandoko in 2000. The result of this study is tomography of P and S wave velocity which can predict position of fracture. The study also attempted to use sum of the wavefronts to obtain position and time of seismic event occurence. Fresnel zone tomography and the summation wavefront can predict location of geological structure of mine area as well.

  9. Hydrothermal fault zone mapping using seismic and electrical measurements

    Science.gov (United States)

    Onacha, Stephen Alumasa

    This dissertation presents a new method of using earthquakes and resistivity data to characterize permeable hydrothermal reservoirs. The method is applied to field examples from Casa Diablo in the Long Valley Caldera, California; Mt. Longonot, Kenya; and Krafla, Iceland. The new method has significant practical value in the exploration and production of geothermal energy. The method uses P- and S-wave velocity, S-wave polarization and splitting magnitude, resistivity and magnetotelluric (MT) strike directions to determine fracture-porosity and orientation. The conceptual model used to characterize the buried, fluid-circulating fault zones in hydrothermal systems is based on geological and fracture models. The method has been tested with field earthquake and resistivity data; core samples; temperature measurements; and, for the case of Krafla, with a drilled well. The use of resistivity and microearthquake measurements is based on theoretical formulation of shared porosity, anisotropy and polarization. The relation of resistivity and a double porosity-operator is solved using a basis function. The porosity-operator is used to generate a correlation function between P-wave velocity and resistivity. This correlation is then used to generate P-wave velocity from 2-D resistivity models. The resistivity models are generated from magnetotelluric (MT) by using the Non-Linear Conjugate Gradient (NLCG) inversion method. The seismic and electrical measurements used come from portable, multi station microearthquake (MEQ) monitoring networks and multi-profile, MT and transient electromagnetic (TEM) observation campaigns. The main conclusions in this dissertation are listed below: (1) Strong evidence exists for correlation between MT strike direction and anisotropy and MEQ S-wave splitting at sites close to fluid-filled fracture zones. (2) A porosity operator generated from a double porosity model has been used to generate valid P-wave velocity models from resistivity data. This

  10. Multi-Fault Rupture Scenarios in the Brawley Seismic Zone

    Science.gov (United States)

    Kyriakopoulos, C.; Oglesby, D. D.; Rockwell, T. K.; Meltzner, A. J.; Barall, M.

    2017-12-01

    Dynamic rupture complexity is strongly affected by both the geometric configuration of a network of faults and pre-stress conditions. Between those two, the geometric configuration is more likely to be anticipated prior to an event. An important factor in the unpredictability of the final rupture pattern of a group of faults is the time-dependent interaction between them. Dynamic rupture models provide a means to investigate this otherwise inscrutable processes. The Brawley Seismic Zone in Southern California is an area in which this approach might be important for inferring potential earthquake sizes and rupture patterns. Dynamic modeling can illuminate how the main faults in this area, the Southern San Andreas (SSAF) and Imperial faults, might interact with the intersecting cross faults, and how the cross faults may modulate rupture on the main faults. We perform 3D finite element modeling of potential earthquakes in this zone assuming an extended array of faults (Figure). Our results include a wide range of ruptures and fault behaviors depending on assumptions about nucleation location, geometric setup, pre-stress conditions, and locking depth. For example, in the majority of our models the cross faults do not strongly participate in the rupture process, giving the impression that they are not typically an aid or an obstacle to the rupture propagation. However, in some cases, particularly when rupture proceeds slowly on the main faults, the cross faults indeed can participate with significant slip, and can even cause rupture termination on one of the main faults. Furthermore, in a complex network of faults we should not preclude the possibility of a large event nucleating on a smaller fault (e.g. a cross fault) and eventually promoting rupture on the main structure. Recent examples include the 2010 Mw 7.1 Darfield (New Zealand) and Mw 7.2 El Mayor-Cucapah (Mexico) earthquakes, where rupture started on a smaller adjacent segment and later cascaded into a larger

  11. Final Report: Seismic Hazard Assessment at the PGDP

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhinmeng [KY Geological Survey, Univ of KY

    2007-06-01

    Selecting a level of seismic hazard at the Paducah Gaseous Diffusion Plant for policy considerations and engineering design is not an easy task because it not only depends on seismic hazard, but also on seismic risk and other related environmental, social, and economic issues. Seismic hazard is the main focus. There is no question that there are seismic hazards at the Paducah Gaseous Diffusion Plant because of its proximity to several known seismic zones, particularly the New Madrid Seismic Zone. The issues in estimating seismic hazard are (1) the methods being used and (2) difficulty in characterizing the uncertainties of seismic sources, earthquake occurrence frequencies, and ground-motion attenuation relationships. This report summarizes how input data were derived, which methodologies were used, and what the hazard estimates at the Paducah Gaseous Diffusion Plant are.

  12. Seismic Measurement of the Locations of the Base of Convection Zone and Helium Ionization Zone for Stars in the Kepler Seismic LEGACY Sample

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Kuldeep; Lund, Mikkel N.; Aguirre, Víctor Silva [Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Raodeo, Keyuri; Mazumdar, Anwesh [Homi Bhabha Centre for Science Education, TIFR, V. N. Purav Marg, Mankhurd, Mumbai 400088 (India); Antia, H. M. [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India); Basu, Sarbani, E-mail: kuldeep@phys.au.dk [Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 065208101 (United States)

    2017-03-01

    Acoustic glitches are regions inside a star where the sound speed or its derivatives change abruptly. These leave a small characteristic oscillatory signature in the stellar oscillation frequencies. With the precision achieved by Kepler seismic data, it is now possible to extract these small amplitude oscillatory signatures, and infer the locations of the glitches. We perform glitch analysis for all the 66 stars in the Kepler seismic LEGACY sample to derive the locations of the base of the envelope convection zone (CZ) and the helium ionization zone. The signature from helium ionization zone is found to be robust for all stars in the sample, whereas the CZ signature is found to be weak and problematic, particularly for relatively massive stars with large errorbars on the oscillation frequencies. We demonstrate that the helium glitch signature can be used to constrain the properties of the helium ionization layers and the helium abundance.

  13. Seismically active fracture zones in the continental wedge above the Andean subduction zone in the Arica Elbow region

    Czech Academy of Sciences Publication Activity Database

    Vaněk, Jiří; Hanuš, Václav; Slancová, Alice; Špičák, Aleš

    2007-01-01

    Roč. 9, č. 1-4 (2007), s. 39-57 ISSN 0163-3171 R&D Projects: GA ČR GA205/95/0264; GA AV ČR IAA3012805 Grant - others:UNESCO(FR) IGCP project No. 345 Institutional research plan: CEZ:AV0Z30120515 Source of funding: V - iné verejné zdroje Keywords : continental lithosphere * Wadati-Benioff zone * seismically active zones Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  14. Bridge seismic retrofit measures considering subduction zone earthquakes.

    Science.gov (United States)

    2015-07-01

    Over the years, earthquakes have exposed the vulnerability of reinforced concrete structures under : seismic loads. The recent occurrence of highly devastating earthquakes near instrumented regions, e.g. 2010 Maule, Chile : and 2011 Tohoku, Japan, ha...

  15. Long seismic activity in the Porto dos Gaúchos Seismic Zone(PGSZ) - Amazon Craton Brazil

    Science.gov (United States)

    Barros, L. V.; Bowen, B. M. D.; Schmidt, K.

    2017-12-01

    The largest earthquake ever observed in the stable continental interior of the South American plate occurred in Serra do Tombador (ST), Mato Grosso state - Brazil, on January 31, 1955 with magnitude 6.2 m b . Since then no other earthquake has been located near the 1955 epicenter. However, in Porto dos Gaúchos (PG), 100 km northeast of ST, a recurrent seismicity has been observed since 1959. Both ST and PG are located in the Phanerozoic Parecis basin whose sediments overlies the crystalline basement of Amazon craton. Two magnitude 5 earthquakes occurred in PG, in 1998 and 2005 with intensities up to VI and V, respectively. These two main shocks were followed by aftershock sequences, studied by local seismic networks, last up today, almost 30 years later, period in which it was detected more than seven thousand of seismic events. Both sequences occurred in the same WSW-ENE oriented fault zone with right-lateral strike-slip mechanisms. The epicentral zone is near the northern border of Parecis basin, where there are buried grabens, generally trending WNW-ESE, such as the deep Mesoproterozoic Caiabis graben which lies partly beneath the Parecis basin. The seismogenic fault is located in a basement high, which is probably related with the same seismogenic feature responsible for the earthquakes in PGSZ. The 1955 earthquake, despite the uncertainty in its epicenter, does not seem to be directly related to any buried graben either. The seismicity in the PGSZ, therefore, is not directly related to rifted crust.Not considering the possibility of miss location in the ST earthquake, its isolated occurrence - from the perspective of new studies on intraplate seismicity - lead us to think that the PGSZ was activated by stresses released by the earthquake of 1955 and that the seismogenic fault of ST would have closed a cycle of activity. This would explain its seismic quiescence. However, other studies are necessary to prove this hypothesis, such as the measurement of the

  16. Growth of a sinkhole in a seismic zone of the Northern Apennines (Italy)

    OpenAIRE

    Rosa, Alessandro; Pagli, Carolina; Molli, Giancarlo; Casu, Francesco; Luca, Claudio; Pieroni, Amerino

    2018-01-01

    Sinkhole collapse is a major hazard causing substantial social and economic losses. However, the surface deformations and sinkhole evolution are rarely recorded, as these sites are known mainly after a collapse, making the assessment of sinkholes-related hazard challenging. Furthermore, 40 % of the sinkholes of Italy are in seismically hazardous zones; it remains unclear whether seismicity may trigger sinkhole collapse. Here we use a multidisciplinary dataset of InSAR, surface mapping ...

  17. Seismic investigation of an ocean-continent transition zone in the northern South China Sea

    Science.gov (United States)

    Zhu, J.; Qiu, X.; Xu, H.; Zhan, W.; Sun, Z.

    2011-12-01

    Rifted continental margins and basins are mainly formed by the lithospheric extension. Thined lithosphere of passive continental margins results in decompression melt of magma and created oceanic crust and thined ocean-continent transition (OCT) zone. Two refraction profiles used ocean bottom seismometers deployed in the broad continental shelf and three multi-channel seismic reflection lines in the northern South China Sea, acquired by the ship "Shiyan 2" of the South China Sea Institute of Oceanology, Chinese Academy of Sciences in 2010, are processed and interpreted in this study. Seismic reflection lines cut through the Dongsha rise, Zhu-1 and Zhu-2 depression within a Tertiary basin, Pear River Mouth basin (called as Zhujiangkou basin). These tectonic features are clear imaged in the seismic reflection records. Numerous normal faults, cutted through the basement and related to the stretch of the northern South China Sea margin, are imaged and interpreted. Reflection characteristics of the ocean-continent transition (OCT) zone are summaried and outlined. The COT zone is mainly divided into the northern syn-rift subsidence zone, central volcano or buried volcano uplift zone and tilt faulted block near the South Chia Sea basin. Compared to the previous seismic reflection data and refraction velocity models, the segmentation range of the OCT zone is outlined, from width of about 225 km in the northeastern South China Sea , of 160 km in the central to of 110 km in the north-central South China Sea. Based on the epicenter distribution of sporadic and large than 6 magnitude earthquakes, it suggests the OCT zone in the northern South China Sea at present is still an active seismic zone.

  18. Reflection seismic methods applied to locating fracture zones in crystalline rock

    International Nuclear Information System (INIS)

    Juhlin, C.

    1998-01-01

    The reflection seismic method is a potentially powerful tool for identifying and localising fracture zones in crystalline rock if used properly. Borehole sonic logs across fracture zones show that they have reduced P-wave velocities compared to the surrounding intact rock. Diagnostically important S-wave velocity log information across the fracture zones is generally lacking. Generation of synthetic reflection seismic data and subsequent processing of these data show that structures dipping up towards 70 degrees from horizontal can be reliably imaged using surface seismic methods. Two real case studies where seismic reflection methods have been used to image fracture zones in crystalline rock are presented. Two examples using reflection seismic are presented. The first is from the 5354 m deep SG-4 borehole in the Middle Urals, Russia where strong seismic reflectors dipping from 25 to 50 degrees are observed on surface seismic reflection data crossing over the borehole. On vertical seismic profile data acquired in the borehole, the observed P-wave reflectivity is weak from these zones, however, strong converted P to S waves are observed. This can be explained by the source of the reflectors being fracture zones with a high P wave to S wave velocity ratio compared to the surrounding rock resulting in a high dependence on the angle of incidence for the reflection coefficient. A high P wave to S wave velocity ratio (high Poisson's ratio) is to be expected in fluid filled fractured rock. The second case is from Aevroe, SE Sweden, where two 1 km long crossing high resolution seismic reflection lines were acquired in October 1996. An E-W line was shot with 5 m geophone and shotpoint spacing and a N-S one with 10 m geophone and shotpoint spacing. An explosive source with a charge size of 100 grams was used along both lines. The data clearly image three major dipping reflectors in the upper 200 ms (600 m). The dipping ones intersect or project to the surface at/or close to

  19. Imaging the Chicxulub central crater zone from large scale seismic acoustic wave propagation and gravity modeling

    Science.gov (United States)

    Fucugauchi, J. U.; Ortiz-Aleman, C.; Martin, R.

    2017-12-01

    Large complex craters are characterized by central uplifts that represent large-scale differential movement of deep basement from the transient cavity. Here we investigate the central sector of the large multiring Chicxulub crater, which has been surveyed by an array of marine, aerial and land-borne geophysical methods. Despite high contrasts in physical properties,contrasting results for the central uplift have been obtained, with seismic reflection surveys showing lack of resolution in the central zone. We develop an integrated seismic and gravity model for the main structural elements, imaging the central basement uplift and melt and breccia units. The 3-D velocity model built from interpolation of seismic data is validated using perfectly matched layer seismic acoustic wave propagation modeling, optimized at grazing incidence using shift in the frequency domain. Modeling shows significant lack of illumination in the central sector, masking presence of the central uplift. Seismic energy remains trapped in an upper low velocity zone corresponding to the sedimentary infill, melt/breccias and surrounding faulted blocks. After conversion of seismic velocities into a volume of density values, we use massive parallel forward gravity modeling to constrain the size and shape of the central uplift that lies at 4.5 km depth, providing a high-resolution image of crater structure.The Bouguer anomaly and gravity response of modeled units show asymmetries, corresponding to the crater structure and distribution of post-impact carbonates, breccias, melt and target sediments

  20. Focused seismicity triggered by flank instability on Kīlauea's Southwest Rift Zone

    Science.gov (United States)

    Judson, Josiah; Thelen, Weston A.; Greenfield, Tim; White, Robert S.

    2018-03-01

    Swarms of earthquakes at the head of the Southwest Rift Zone on Kīlauea Volcano, Hawai´i, reveal an interaction of normal and strike-slip faulting associated with movement of Kīlauea's south flank. A relocated subset of earthquakes between January 2012 and August 2014 are highly focused in space and time at depths that are coincident with the south caldera magma reservoir beneath the southern margin of Kīlauea Caldera. Newly calculated focal mechanisms are dominantly dextral shear with a north-south preferred fault orientation. Two earthquakes within this focused area of seismicity have normal faulting mechanisms, indicating two mechanisms of failure in very close proximity (10's of meters to 100 m). We suggest a model where opening along the Southwest Rift Zone caused by seaward motion of the south flank permits injection of magma and subsequent freezing of a plug, which then fails in a right-lateral strike-slip sense, consistent with the direction of movement of the south flank. The seismicity is concentrated in an area where a constriction occurs between a normal fault and the deeper magma transport system into the Southwest Rift Zone. Although in many ways the Southwest Rift Zone appears analogous to the more active East Rift Zone, the localization of the largest seismicity (>M2.5) within the swarms to a small volume necessitates a different model than has been proposed to explain the lineament outlined by earthquakes along the East Rift Zone.

  1. Mapping Inherited Fractures in the Critical Zone Using Seismic Anisotropy From Circular Surveys

    Science.gov (United States)

    Novitsky, Christopher G.; Holbrook, W. Steven; Carr, Bradley J.; Pasquet, Sylvain; Okaya, David; Flinchum, Brady A.

    2018-04-01

    Weathering and hydrological processes in Earth's shallow subsurface are influenced by inherited bedrock structures, such as bedding planes, faults, joints, and fractures. However, these structures are difficult to observe in soil-mantled landscapes. Steeply dipping structures with a dominant orientation are detectable by seismic anisotropy, with fast wave speeds along the strike of structures. We measured shallow ( 2-4 m) seismic anisotropy using "circle shots," geophones deployed in a circle around a central shot point, in a weathered granite terrain in the Laramie Range of Wyoming. The inferred remnant fracture orientations agree with brittle fracture orientations measured at tens of meters depth in boreholes, demonstrating that bedrock fractures persist through the weathering process into the shallow critical zone. Seismic anisotropy positively correlates with saprolite thickness, suggesting that inherited bedrock fractures may control saprolite thickness by providing preferential pathways for corrosive meteoric waters to access the deep critical zone.

  2. ACTIVITY AND Vp/Vs RATIO OF VOLCANO-TECTONIC SEISMIC SWARM ZONES AT NEVADO DEL RUIZ VOLCANO, COLOMBIA

    Directory of Open Access Journals (Sweden)

    Londoño B. John Makario

    2010-06-01

    Full Text Available An analysis of the seismic activity for volcano-tectonic earthquake (VT swarms zones at Nevado del Ruiz Volcano (NRV was carried out for the interval 1985- 2002, which is the most seismic active period at NRV until now (2010. The swarm-like seismicity of NRV was frequently concentrated in very well defined clusters around the volcano. The seismic swarm zone located at the active crater was the most active during the entire time. The seismic swarm zone located to the west of the volcano suggested some relationship with the volcanic crises. It was active before and after the two eruptions occurred in November 1985 and September 1989. It is believed that this seismic activity may be used as a monitoring tool of volcanic activity. For each seismic swarm zone the Vp/Vs ratio was also calculated by grouping of earthquakes and stations. It was found that each seismic swarm zone had a distinct Vp/Vs ratio with respect to the others, except for the crater and west swarm zones, which had the same value. The average Vp/Vs ratios for the seismic swarm zones located at the active crater and to the west of the volcano are about 6-7% lower than that for the north swarm zone, and about 3% lower than that for the south swarm zone. We suggest that the reduction of the Vp/Vs ratio is due to degassing phenomena inside the central and western earthquake swarm zones, or due to the presence of microcracks inside the volcano. This supposition is in agreement with other studies of geophysics, geochemistry and drilling surveys carried out at NRV.

  3. Juan de Fuca slab geometry and its relation to Wadati-Benioff zone seismicity

    Science.gov (United States)

    McCrory, Patricia A.; Blair, J. Luke; Waldhause, Felix; Oppenheimer, David H.

    2012-01-01

    A new model of the subducted Juan de Fuca plate beneath western North America allows first-order correlations between the occurrence of Wadati-Benioff zone earthquakes and slab geometry, temperature, and hydration state. The geo-referenced 3D model, constructed from weighted control points, integrates depth information from earthquake locations and regional seismic velocity studies. We use the model to separate earthquakes that occur in the Cascadia forearc from those that occur within the underlying Juan de Fuca plate and thereby reveal previously obscured details regarding the spatial distribution of earthquakes. Seismicity within the slab is most prevalent where the slab is warped beneath northwestern California and western Washington suggesting that slab flexure, in addition to expected metamorphic dehydration processes, promotes earthquake occurrence within the subducted oceanic plate. Earthquake patterns beneath western Vancouver Island are consistent with slab dehydration processes. Conversely, the lack of slab earthquakes beneath western Oregon is consistent with an anhydrous slab. Double-differenced relocated seismicity resolves a double seismic zone within the slab beneath northwestern California that strongly constrains the location of the plate interface and delineates a cluster of seismicity 10 km above the surface that includes the 1992 M7.1 Mendocino earthquake. We infer that this earthquake ruptured a surface within the Cascadia accretionary margin above the Juan de Fuca plate. We further speculate that this earthquake is associated with a detached fragment of former Farallon plate. Other subsurface tectonic elements within the forearc may have the potential to generate similar damaging earthquakes.

  4. Subduction zone locking, strain partitioning, intraplate deformation and their implications to Seismic Hazards in South America

    Science.gov (United States)

    Galgana, G. A.; Mahdyiar, M.; Shen-Tu, B.; Pontbriand, C. W.; Klein, E.; Wang, F.; Shabestari, K.; Yang, W.

    2014-12-01

    We analyze active crustal deformation in South America (SA) using published GPS observations and historic seismicity along the Nazca Trench and the active Ecuador-Colombia-Venezuela Plate boundary Zone. GPS-constrained kinematisc models that incorporate block and continuum techniques are used to assess patterns of regional tectonic deformation and its implications to seismic potential. We determine interplate coupling distributions, fault slip-rates, and intraplate crustal strain rates in combination with historic earthquakes within 40 seismic zones crust to provide moment rate constraints. Along the Nazca subduction zone, we resolve a series of highly coupled patches, interpreted as high-friction producing "asperities" beneath the coasts of Ecuador, Peru and Chile. These include areas responsible for the 2010 Mw 8.8 Maule Earthquake and the 2014 Mw 8.2 Iquique Earthquake. Predicted tectonic block motions and fault slip rates reveal that the northern part of South America deforms rapidly, with crustal fault slip rates as much as ~20 mm/a. Fault slip and locking patterns reveal that the Oca Ancón-Pilar-Boconó fault system plays a key role in absorbing most of the complex eastward and southward convergence patterns in northeastern Colombia and Venezuela, while the near-parallel system of faults in eastern Colombia and Ecuador absorb part of the transpressional motion due to the ~55 mm/a Nazca-SA plate convergence. These kinematic models, in combination with historic seismicity rates, provide moment deficit rates that reveal regions with high seismic potential, such as coastal Ecuador, Bucaramanga, Arica and Antofagasta. We eventually use the combined information from moment rates and fault coupling patterns to further constrain stochastic seismic hazard models of the region by implementing realistic trench rupture scenarios (see Mahdyiar et al., this volume).

  5. Seismotectonics of Vrancea (Romania) zone: the case of crustal seismicity in the foredeep area

    International Nuclear Information System (INIS)

    Tugui, A.; Craiu, M.; Rogozea, M.; Popa, M.; Radulian, M.; http://www.infp.ro

    2009-01-01

    Vrancea seismic zone is located in Romania at the South-Easter Carpathians bend, where at least three major tectonic units are in contact: East European Plate, Intra-Alpine Plate and Moesian Plate. The seismicity of the Vrancea zone consists of both crustal and intermediate-depth earthquakes. The crustal events are moderate (M w ≤ 5.5) and generally occur in clusters in space (the subzones Ramnicu Sarat and Vrancioaia, situated in the Vrancea epicentral area and adjacent to it) and in time (main shocks accompanied by aftershocks and sometimes by foreshocks or swarms). Seismic activity in Ramnicu Sarat zone consists of shallow earthquakes with moderate magnitudes M s ≤ 5.2, which frequently occur in clusters. The hypocenters are generally situated at focal depths between 15 and 30 km within the foredeep region lying in front of the major bending of the Carpathian Arc. The sequence of 29 November - 03 December, 2007 consists of 37 events with 1.8 ≤ M D ≤ 3.9. The earthquakes hypocenters are grouped in a parallel direction with the Carpathian Bend, and the fault plane solution (of the main shock) is reverse. The seismic sequence from Ramnicu Sarat, 2007 was compared with the previous sequences knowing the regional seismotectonics. (authors)

  6. Seismic Evidence of A Widely Distributed West Napa Fault Zone, Hendry Winery, Napa, California

    Science.gov (United States)

    Goldman, M.; Catchings, R.; Chan, J. H.; Criley, C.

    2015-12-01

    Following the 24 August 2014 Mw 6.0 South Napa earthquake, surface rupture was mapped along the West Napa Fault Zone (WNFZ) for a distance of ~ 14 km and locally within zones up to ~ 2 km wide. Near the northern end of the surface rupture, however, several strands coalesced to form a narrow, ~100-m-wide zone of surface rupture. To determine the location, width, and shallow (upper few hundred meters) geometry of the fault zone, we acquired an active-source seismic survey across the northern surface rupture in February 2015. We acquired both P- and S-wave data, from which we developed reflection images and tomographic images of Vp, Vs, Vp/Vs, and Poisson's ratio of the upper 100 m. We also used small explosive charges within surface ruptures located ~600 m north of our seismic array to record fault-zone guided waves. Our data indicate that at the latitude of the Hendry Winery, the WNFZ is characterized by at least five fault traces that are spaced 60 to 200 m apart. Zones of low-Vs, low-Vp/Vs, and disrupted reflectors highlight the fault traces on the tomography and reflection images. On peak-ground-velocity (PGV) plots, the most pronounced high-amplitude guided-wave seismic energy coincides precisely with the mapped surface ruptures, and the guided waves also show discrete high PGV zones associated with unmapped fault traces east of the surface ruptures. Although the surface ruptures of the WNFZ were observed only over a 100-m-wide zone at the Hendry Winery, our data indicate that the fault zone is at least 400 m wide, which is probably a minimum width given the 400-m length of our seismic profile. Slip on the WNFZ is generally considered to be low relative to most other Bay Area faults, but we suggest that the West Napa Fault is a zone of widely distributed shear, and to fully account for the total slip on the WNFZ, slip on all traces of this wide fault zone must be considered.

  7. Seismic properties of lawsonite eclogites from the southern Motagua fault zone, Guatemala

    Science.gov (United States)

    Kim, Daeyeong; Wallis, Simon; Endo, Shunsuke; Ree, Jin-Han

    2016-05-01

    We present new data on the crystal preferred orientation (CPO) and seismic properties of omphacite and lawsonite in extremely fresh eclogite from the southern Motagua fault zone, Guatemala, to discuss the seismic anisotropy of subducting oceanic crust. The CPO of omphacite is characterized by (010)[001], and it shows P-wave seismic anisotropies (AVP) of 1.4%-3.2% and S-wave seismic anisotropies (AVS) of 1.4%-2.7%. Lawsonite exhibits (001) planes parallel to the foliation and [010] axes parallel to the lineation, and seismic anisotropies of 1.7%-6.6% AVP and 3.4%-14.7% AVS. The seismic anisotropy of a rock mass consisting solely of omphacite and lawsonite is 1.2%-4.1% AVP and 1.8%-6.8% AVS. For events that propagate more or less parallel to the maximum extension direction, X, the fast S-wave velocity (VS) polarization is parallel to the Z in the Y-Z section (rotated from the X-Z section), causing trench-normal seismic anisotropy for orthogonal subduction. Based on the high modal abundance and strong fabric of lawsonite, the AVS of eclogites is estimated as ~ 11.7% in the case that lawsonite makes up ~ 75% of the rock mass. On this basis, we suggest that lawsonite in both blueschist and eclogite may play important roles in the formation of complex pattern of seismic anisotropy observed in NE Japan: weak trench-parallel anisotropy in the forearc basin domains and trench-normal anisotropy in the backarc region.

  8. Evidence for strong Holocene earthquake(s) in the Wabash Valley seismic zone

    International Nuclear Information System (INIS)

    Obermeier, S.

    1991-01-01

    Many small and slightly damaging earthquakes have taken place in the region of the lower Wabash River Valley of Indiana and Illinois during the 200 years of historic record. Seismologists have long suspected the Wabash Valley seismic zone to be capable of producing earthquakes much stronger than the largest of record (m b 5.8). The seismic zone contains the poorly defined Wabash Valley fault zone and also appears to contain other vaguely defined faults at depths from which the strongest earthquakes presently originate. Faults near the surface are generally covered with thick alluvium in lowlands and a veneer of loess in uplands, which make direct observations of faults difficult. Partly because of this difficulty, a search for paleoliquefaction features was begun in 1990. Conclusions of the study are as follows: (1) an earthquake much stronger than any historic earthquake struck the lower Wabash Valley between 1,500 and 7,500 years ago; (2) the epicentral region of the prehistoric strong earthquake was the Wabash Valley seismic zone; (3) apparent sites have been located where 1811-12 earthquake accelerations can be bracketed

  9. The hydraulic structure of the Gole Larghe Fault Zone (Italian Southern Alps) through the seismic cycle

    Science.gov (United States)

    Bistacchi, A.; Mittempergher, S.; Di Toro, G.; Smith, S. A. F.; Garofalo, P. S.

    2017-12-01

    The 600 m-thick, strike slip Gole Larghe Fault Zone (GLFZ) experienced several hundred seismic slip events at c. 8 km depth, well-documented by numerous pseudotachylytes, was then exhumed and is now exposed in beautiful and very continuous outcrops. The fault zone was also characterized by hydrous fluid flow during the seismic cycle, demonstrated by alteration halos and precipitation of hydrothermal minerals in veins and cataclasites. We have characterized the GLFZ with > 2 km of scanlines and semi-automatic mapping of faults and fractures on several photogrammetric 3D Digital Outcrop Models (3D DOMs). This allowed us obtaining 3D Discrete Fracture Network (DFN) models, based on robust probability density functions for parameters of fault and fracture sets, and simulating the fault zone hydraulic properties. In addition, the correlation between evidences of fluid flow and the fault/fracture network parameters have been studied with a geostatistical approach, allowing generating more realistic time-varying permeability models of the fault zone. Based on this dataset, we have developed a FEM hydraulic model of the GLFZ for a period of some tens of years, covering one seismic event and a postseismic period. The higher permeability is attained in the syn- to early post-seismic period, when fractures are (re)opened by off-fault deformation, then permeability decreases in the postseismic due to fracture sealing. The flow model yields a flow pattern consistent with the observed alteration/mineralization pattern and a marked channelling of fluid flow in the inner part of the fault zone, due to permeability anisotropy related to the spatial arrangement of different fracture sets. Amongst possible seismological applications of our study, we will discuss the possibility to evaluate the coseismic fracture intensity due to off-fault damage, and the heterogeneity and evolution of mechanical parameters due to fluid-rock interaction.

  10. Seismic evidence for deep fluid circulation in the overriding plate of subduction zones

    Science.gov (United States)

    Tauzin, B.; Reynard, B.; Bodin, T.; Perrillat, J. P.; Debayle, E.

    2015-12-01

    In subduction zones, non-volcanic tremors are associated with fluid circulations (Obara, 2002). Their sources are often located on the interplate boundary (Rogers and Dragert, 2003; Shelly et al, 2006; La Rocca, 2009), consistent with fluids released by the dehydration of subducted plates (Hacker et al., 2003). Reports of tremors in the overriding continental crust of several subduction zones in the world (Kao et al., 2005; Payero et al., 2008; Ide, 2012) suggest fluid circulation at shallower depths but potential fluid paths are poorly documented. Here we obtained seismic observations from receiver functions that evidence the close association between the shallow tremor zone, electrical conductivity, and tectonic features of the Cascadia overriding plate. A seismic discontinuity near 15 km depth in the crust of the overriding North American plate is attributed to the Conrad discontinuity. This interface is segmented, and its interruption is spatially correlated with conductive regions and shallow swarms of seismicity and non-volcanic tremors. These observations suggest that shallow fluid circulation, tremors and seismicity are controlled by fault zones limiting blocks of accreted terranes in the overriding plate (Brudzinski and Allen, 2007). These zones constitute fluid "escape" routes that may contribute unloading fluid pressure on the megathrust. Obara, K. (2002). Science, 296, 1679-1681. Rogers, G., & Dragert, H. (2003). Science, 300, 1942-1943. Shelly, D. R., et al. (2006). Nature, 442, 188-191. La Rocca, M., et al. (2009). Science, 323, 620-623. Kao, H., et al. (2005). Nature, 436, 841-844. Payero, J. S., et al. (2008). Geophysical Research Letters, 35. Ide, S. (2012). Journal of Geophysical Research: Solid Earth, 117. Brudzinski, M. R., & Allen, R. M. (2007). Geology, 35, 907-910.

  11. Methodology of seismotectonic zoning in an intraplate low seismicity domain. Examples of France surrounding areas

    International Nuclear Information System (INIS)

    Philip, H.; Grellet, B.; Combes, P.; Haessler, H.

    1991-01-01

    Until now, the dominant factor in seismic hazard assessments has been historical seismicity. This approach is justified if the data derived from historical seismicity in a region are representative of its seismic activity and if we consider that in areas where damaging earthquakes have happened, they may happen again. This can be seen when seismotectonic relationships are well established in areas such as well localised plate boundaries (subduction zones, transform faults) and/or with a high rate of deformation. In these cases, the areas where future earthquakes might occur are usually well determined and the recurrences short enough on the time scale of historical observations. However, in areas where recent tectonic deformations are diffused and moderate, the historical period of seismicity data (a few centuries) is not long enough to observe a sample of historical seismicity representative of the present-day tectonic activity of the area. The studies on the most recent damaging earthquakes (El Asnam 1980, Spitak 1988, Cherchell Tipasa 1989) show that it would have been extremely difficult to predict the magnitude and the localisation of these events considering historical seismicity alone. It is the same in Provence (south of France) where the risk of occurrence of a damaging earthquake would have been underestimated before the June 1909 event. In all these cases, seismotectonic studies 'a posteriori' show that the geometry and kinematic of the faults responsible for these earthquakes can be identified and that all of them have presented seismic activity in the last thousand years. So it is necessary to emphasis a global approach of the problem through specific studies such as neotectonics, teledetection, geodesy, present-day stress field, strain field, paleoseismology etc. These studies will enlarge the period of observation compared with the data derived only from historical and present-day seismicity. In France seismicity is moderate and recent tectonic

  12. Reinforced concrete containment structures in high seismic zones

    International Nuclear Information System (INIS)

    Aziz, T.S.

    1977-01-01

    A new structural concept for reinforced concrete containment structures at sites where earthquake ground motions in terms of the Safe Shutdown Earthquake (SSE) exceeds 0.3 g is presented. The structural concept is based on: (1) an inner steel-lined concrete shell which houses the reactor and provides shielding and containment in the event of loss of coolant accident; (2) an outer annular concrete shell structure which houses auxilary reactor equipment and safeguards systems. These shell structures are supported on a common foundation mat which is embeded in the subgrade. Under stipulated earthquake conditions the two shell structures interact to resist lateral inertia forces. Thus the annular structure which is not a pressure boundary acts as a lateral support for the inner containment shell. The concept is practical, economically feasible and new to practice. An integrated configuration which includes the interior shell, the annular structure and the subgrade is analyzed for several static and dynamic loading conditions. The analysis is done using a finite difference solution scheme for the static loading conditions. A semi-analytical three-dimensional finite element scheme combined with a Fast Fourier Transform (FFT) algorithm is used for the dynamic loading conditions. The effects of cracking of the containment structure due to pressurization in conjunction with earthquake loading are discussed. Analytical results for both the finite difference and the finite element schemes are presented and the sensitivity of the results to changes in the input parameters is studied. General recommendations are given for plant configurations where high seismic loading is a major design consideration

  13. Paleoearthquakes and long-term seismic regime in the Longmenshan fault zone, Southwest China

    Science.gov (United States)

    Liu, J.; Rodina, S. N.; Rogozhin, E. A.

    2017-11-01

    The collected paleoseismological data about the ancient earthquakes are analyzed for the zone of the Wenchuan earthquake. Four earthquakes with magnitude M = 8.0 occurred over a period of 10000 years and two earthquakes with magnitude 7.5 occurred over 1200 years. The obtained data allowed us to reconstruct the long-term seismic regime within the studied territory by constructing the frequency-magnitude relationship based on the instrumental, historical, and paleoseismological data.

  14. A comparison of seismicity in world's subduction zones: Implication by the difference of b-values

    Science.gov (United States)

    Nishikawa, T.; Ide, S.

    2013-12-01

    Since the pioneering study of Uyeda and Kanamori (1979), it has been thought that world's subduction zones can be classified into two types: Chile and Mariana types. Ruff and Kanamori (1980) suggested that the maximum earthquake size within each subduction zone correlates with convergence rate and age of subducting lithosphere. Subduction zones with younger lithosphere and larger convergence rates are associated with great earthquakes (Chile), while subduction zones with older lithosphere and smaller convergence rates have low seismicity (Mariana). However, these correlations are obscured after the 2004 Sumatra earthquake and the 2009 Tohoku earthquake. Furthermore, McCaffrey (2008) pointed out that the history of observation is much shorter than the recurrence times of very large earthquakes, suggesting a possibility that any subduction zone may produce earthquakes larger than magnitude 9. In the present study, we compare world's subduction zones in terms of b-values in the Gutenberg-Richer relation. We divided world's subduction zones into 146 regions, each of which is bordered by a trench section of about 500 km and extends for 200 km from the trench section in the direction of relative plate motion. In each region, earthquakes equal to or larger than M4.5 occurring during 1988-2009 were extracted from ISC catalog. We find a positive correlation between b-values and ages of subducting lithosphere, which is one of the two important variables discussed in Ruff and Kanamori (1980). Subduction zones with younger lithosphere are associated with high b-values and vice versa, while we cannot find a correlation between b-values and convergence rates. We used the ages determined by Müller et al. (2008) and convergence rate calculated using PB2002 (Bird, 2003) for convergence rate. We also found a negative correlation between b-values and the estimates of seismic coupling, which is defined as the ratio of the observed seismic moment release rate to the rate calculated

  15. Heterogeneous distribution of water in the mantle transition zone beneath United States inferred from seismic observations

    Science.gov (United States)

    Wang, Y.; Pavlis, G. L.; Li, M.

    2017-12-01

    The amount of water in the Earth's deep mantle is critical for the evolution of the solid Earth and the atmosphere. Mineral physics studies have revealed that Wadsleyite and Ringwoodite in the mantle transition zone could store several times the volume of water in the ocean. However, the water content and its distribution in the transition zone remain enigmatic due to lack of direct observations. Here we use seismic data from the full deployment of the Earthscope Transportable Array to produce 3D image of P to S scattering of the mantle transition zone beneath the United States. We compute the image volume from 141,080 pairs of high quality receiver functions defined by the Earthscope Automated Receiver Survey, reprocessed by the generalized iterative deconvolution method and imaged by the plane wave migration method. We find that the transition zone is filled with previously unrecognized small-scale heterogeneities that produce pervasive, negative polarity P to S conversions. Seismic synthetic modeling using a point source simulation method suggests two possible structures for these objects: 1) a set of randomly distributed blobs of slight difference in size, and 2) near vertical diapir structures from small scale convections. Combining with geodynamic simulations, we interpret the observation as compositional heterogeneity from small-scale, low-velocity bodies that are water enriched. Our results indicate there is a heterogeneous distribution of water through the entire mantle transition zone beneath the contiguous United States.

  16. Peru Subduction Zone Seismic Experiment (PeruSZE): Preliminary Results From a Seismic Network Between Mollendo and Lake Titicaca, Peru.

    Science.gov (United States)

    Guy, R.; Stubailo, I.; Skinner, S.; Phillips, K.; Foote, E.; Lukac, M.; Aguilar, V.; Tavera, H.; Audin, L.; Husker, A.; Clayton, R.; Davis, P. M.

    2008-12-01

    This work describes preliminary results from a 50 station broadband seismic network recently installed from the coast to the high Andes in Peru. UCLA's Center for Embedded Network Sensing (CENS) and Caltech's Tectonic Observatory are collaborating with the IRD (French L'Institut de Recherche pour le Developpement) and the Institute of Geophysics, in Lima Peru in a broadband seismic experiment that will study the transition from steep to shallow slab subduction. The currently installed line has stations located above the steep subduction zone at a spacing of about 6 km. In 2009 we plan to install a line of 50 stations north from this line along the crest of the Andes, crossing the transition from steep to shallow subduction. A further line from the end of that line back to the coast, completing a U shaped array, is in the planning phase. The network is wirelessly linked using multi-hop network software designed by computer scientists in CENS in which data is transmitted from station to station, and collected at Internet drops, from where it is transmitted over the Internet to CENS each night. The instrument installation in Peru is almost finished and we have been receiving data daily from 10 stations (out of total 50) since June 2008. The rest are recording on-site while the RF network is being completed. The software system provides dynamic link quality based routing, reliable data delivery, and a disruption tolerant shell interface for managing the system from UCLA without the need to travel to Peru. The near real-time data delivery also allows immediate detection of any problems at the sites. We are building a seismic data and GPS quality control toolset that would greatly minimize the station's downtime by alerting the users of any possible problems.

  17. Double seismic zone in downgoing slabs and the viscosity of the mesosphere

    International Nuclear Information System (INIS)

    Sleep, N.H.

    1979-01-01

    The seismic zone beneath several island arcs between about 100 and 200 km depth consists of an upper zone having down-dip compression and a lower zone having down-dip tension. Several numerical models of the Aleutina arc were computed to test the hypothesis that these double seismic zones are due to sagging of the slab under its own weight. This sagging occurs because the asthenosphere (between about 100 and 200 km) provides little support or resistance to the slab, which is supported from below by the more viscous mesosphere and from above by the lithosphere. The viscosity of the mesosphere was constrained to the interval between 0.25 x 10 22 and 0.5 x 10 22 P by noting that the slab would have mainly down-dip compression at higher viscosities and mainly down-dip tension at lower viscosities. The deviatoric stress in the slab and the fault plane between the slab and the island arc is about 200--300 bars (expressed as shear stress). The models were calibrated to the observed depth and gravity anomalies in the trench

  18. Seismic imaging along a 600 km transect of the Alaska Subduction zone (Invited)

    Science.gov (United States)

    Calkins, J. A.; Abers, G. A.; Freymueller, J. T.; Rondenay, S.; Christensen, D. H.

    2010-12-01

    We present earthquake locations, scattered wavefield migration images, and phase velocity maps from preliminary analysis of combined seismic data from the Broadband Experiment Across the Alaska Range (BEAAR) and Multidisciplinary Observations of Onshore Subduction (MOOS) projects. Together, these PASSCAL broadband arrays sampled a 500+ km transect across a portion of the subduction zone characterized by the Yakutat terrane/Pacific plate boundary in the downgoing plate, and the Denali volcanic gap in the overriding plate. These are the first results from the MOOS experiment, a 34-station array that was deployed from 2006-2008 to fill in the gap between the TACT offshore refraction profile (south and east of the coastline of the Kenai Peninsula), and the BEAAR array (spanning the Alaska Range between Talkeetna and Fairbanks). 2-D images of the upper 150 km of the subduction zone were produced by migrating forward- and back-scattered arrivals in the coda of P waves from large teleseismic earthquakes, highlighting S-velocity perturbations from a smoothly-varying background model. The migration images reveal a shallowly north-dipping low velocity zone that is contiguous near 20 km depth on its updip end with previously obtained images of the subducting plate offshore. The low velocity zone steepens further to the north, and terminates near 120 km beneath the Alaska Range. We interpret this low velocity zone to be the crust of the downgoing plate, and the reduced seismic velocities to be indicative of hydrated gabbroic compositions. Earthquakes located using the temporary arrays and nearby stations of the Alaska Regional Seismic Network correlate spatially with the inferred subducting crust. Cross-sections taken along nearly orthogonal strike lines through the MOOS array reveal that both the dip angle and the thickness of the subducting low velocity zone change abruptly across a roughly NNW-SSE striking line drawn through the eastern Kenai Peninsula, coincident with a

  19. Seismic Velocity Structure across the Hayward Fault Zone Near San Leandro, California

    Science.gov (United States)

    Strayer, L. M.; Catchings, R.; Chan, J. H.; Richardson, I. S.; McEvilly, A.; Goldman, M.; Criley, C.; Sickler, R. R.

    2017-12-01

    In Fall 2016 we conducted the East Bay Seismic Investigation, a NEHRP-funded collaboration between California State University, East Bay and the United State Geological Survey. The study produced a large volume of seismic data, allowing us to examine the subsurface across the East Bay plain and hills using a variety of geophysical methods. We know of no other survey performed in the past that has imaged this area, at this scale, and with this degree of resolution. Initial models show that seismic velocities of the Hayward Fault Zone (HFZ), the East Bay plain, and the East Bay hills are illuminated to depths of 5-6 km. We used explosive sources at 1-km intervals along a 15-km-long, NE-striking ( 055°), seismic line centered on the HFZ. Vertical- and horizontal-component sensors were spaced at 100 m intervals along the entire profile, with vertical-component sensors at 20 m intervals across mapped or suspected faults. Preliminary seismic refraction tomography across the HFZ, sensu lato, (includes sub-parallel, connected, and related faults), shows that the San Leandro Block (SLB) is a low-velocity feature in the upper 1-3 km, with nearly the same Vp as the adjacent Great Valley sediments to the east, and low Vs values. In our initial analysis we can trace the SLB and its bounding faults (Hayward, Chabot) nearly vertically, to at least 2-4 km depth. Similarly, preliminary migrated reflection images suggest that many if not all of the peripheral reverse, strike-slip and oblique-slip faults of the wider HFZ dip toward the SLB, into a curtain of relocated epicenters that define the HFZ at depth, indicative of a `flower-structure'. Preliminary Vs tomography identifies another apparently weak zone at depth, located about 1.5 km east of the San Leandro shoreline, that may represent the northward continuation of the Silver Creek Fault. Centered 4 km from the Bay, there is a distinctive, 2 km-wide, uplifted, horst-like, high-velocity structure (both Vp & Vs) that bounds the

  20. Water, oceanic fracture zones and the lubrication of subducting plate boundaries—insights from seismicity

    Science.gov (United States)

    Schlaphorst, David; Kendall, J.-Michael; Collier, Jenny S.; Verdon, James P.; Blundy, Jon; Baptie, Brian; Latchman, Joan L.; Massin, Frederic; Bouin, Marie-Paule

    2016-03-01

    We investigate the relationship between subduction processes and related seismicity for the Lesser Antilles Arc using the Gutenberg-Richter law. This power law describes the earthquake-magnitude distribution, with the gradient of the cumulative magnitude distribution being commonly known as the b-value. The Lesser Antilles Arc was chosen because of its along-strike variability in sediment subduction and the transition from subduction to strike-slip movement towards its northern and southern ends. The data are derived from the seismicity catalogues from the Seismic Research Centre of The University of the West Indies and the Observatoires Volcanologiques et Sismologiques of the Institut de Physique du Globe de Paris and consist of subcrustal events primarily from the slab interface. The b-value is found using a Kolmogorov-Smirnov test for a maximum-likelihood straight line-fitting routine. We investigate spatial variations in b-values using a grid-search with circular cells as well as an along-arc projection. Tests with different algorithms and the two independent earthquake cataloges provide confidence in the robustness of our results. We observe a strong spatial variability of the b-value that cannot be explained by the uncertainties. Rather than obtaining a simple north-south b-value distribution suggestive of the dominant control on earthquake triggering being water released from the sedimentary cover on the incoming American Plates, or a b-value distribution that correlates with on the obliquity of subduction, we obtain a series of discrete, high b-value `bull's-eyes' along strike. These bull's-eyes, which indicate stress release through a higher fraction of small earthquakes, coincide with the locations of known incoming oceanic fracture zones on the American Plates. We interpret the results in terms of water being delivered to the Lesser Antilles subduction zone in the vicinity of fracture zones providing lubrication and thus changing the character of the

  1. Seismic investigation on the Littoral Faults Zone in the northern continental margin of South China Sea

    Science.gov (United States)

    Sun, J.; Xu, H.; Xia, S.; Cao, J.; Wan, K.

    2017-12-01

    The continental margin of the northern South China Sea (SCS) had experienced continuous evolution from an active continental margin in the late Mesozoic to a passive continental margin in the Cenozoic. The 1200km-long Littoral Faults Zone (LFZ) off the mainland South China was suggested to represent one of the sub-plate boundaries and play a key role during the evolution. Besides, four devastating earthquakes with magnitude over 7 and another 11 destructive events with M>6 were documented to have occurred along the LFZ. However, its approximity to the shoreline, the shallow water depth, and the heavy fishing activities make it hard to conduct a marine seismic investigation. As a result, understandings about the LFZ before 2000 were relatively poor and mostly descriptive. After two experiments of joint onshore-offshore wide-angle seismic surveys in the 1st decade of this century, several cruses aiming to unveil the deep structure of the LFZ were performed in the past few years, with five joint onshore-offshore wide-angle seismic survey profiles completed. Each of these profiles is perpendicular to the shoreline, with four to five seismometers of campaign mode deployed on the landside and over ten Ocean Bottom Seismometers (OBSs) spacing at 20km deployed on the seaside. Meanwhile, multi-channel seismic (MCS) data along these profiles were obtained simultaneously. Based on these data, velocity models from both forward modeling and inversion were obtained. According to these models, the LFZ was imaged to be a low-velocity fractured zone dipping to the SSE-SE at a high-angle and cutting through the thinned continental crust at some locations. Width of the fractured zone varies from 6km to more than 10km from site to site. With these results, it is suggested that the LFZ accommodates the stresses from both the east side, where the Eurasia/Philippine Sea plate converging and mountain building is ongoing, and the west side, where a strike-slip between the Indochina

  2. Seismic response of earth dams considering dynamic properties of unsaturated zone

    Directory of Open Access Journals (Sweden)

    Ariyan M.

    2016-01-01

    Full Text Available It is conventionally assumed in the analysis and design of earth dams that the soil located above the phreatic line, i.e. the uppermost seepage flow line, is completely dry. However, there is often an unsaturated flow of water through an unsaturated zone above this borderline and variation in moisture content in this zone results in variation of matric suction throughout this region. Variation of matric suction, in turn, results in variation of effective stresses in this zone. In this research, the seismic response of earth dams in terms of the displacement and acceleration at the crown of the dam as well as the stress distribution in the dam body is investigated. Taking into account the effect of unsaturated zone, a comparison is made to investigate the effect of conventional simplification in ignoring the dynamic characteristics of the unsaturated zone above the phreatic line and the more complicated analysis which includes the unsaturated zone. A function for the soil-water retention curve (SWRC was assigned to the soil in the unsaturated zone to determine the variation of matric suction in this zone and analyses were made using finite difference software (FLAC. Results are then compared to the conventional method for homogeneous dams. In these analyzes the soil shear modulus was assumed to vary with the mean effective stress both for saturated and unsaturated zones. Among various results, it was notable that the history of crest x-displacement, and acceleration show higher values in models accounting for the unsaturated region. It was attributed to the considerably lower values of damping ratio in the crest region in the unsaturated models.

  3. Preliminary results of characteristic seismic anisotropy beneath Sunda-Banda subduction-collision zone

    Energy Technology Data Exchange (ETDEWEB)

    Wiyono, Samsul H., E-mail: samsul.wiyono@bmkg.go.id [Study Program of Earth Sciences, Faculty of Earth Sciences and Technology, Institute of Technology Bandung, Bandung 40132 (Indonesia); Indonesia’s Agency for Meteorology Climatology and Geophysics, Jakarta 10610 (Indonesia); Nugraha, Andri Dian, E-mail: nugraha@gf.itb.ac.id [Indonesia’s Agency for Meteorology Climatology and Geophysics, Jakarta 10610 (Indonesia); Global Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Bandung 40132, Indonesia, Phone: +62-22 2534137 (Indonesia)

    2015-04-24

    Determining of seismic anisotropy allowed us for understanding the deformation processes that occured in the past and present. In this study, we performed shear wave splitting to characterize seismic anisotropy beneath Sunda-Banda subduction-collision zone. For about 1,610 XKS waveforms from INATEWS-BMKG networks have been analyzed. From its measurements showed that fast polarization direction is consistent with trench-perpendicular orientation but several stations presented different orientation. We also compared between fast polarization direction with absolute plate motion in the no net rotation and hotspot frame. Its result showed that both absolute plate motion frame had strong correlation with fast polarization direction. Strong correlation between the fast polarization direction and the absolute plate motion can be interpreted as the possibility of dominant anisotropy is in the asthenosphere.

  4. New Insights on the Structure of the Cascadia Subduction Zone from Amphibious Seismic Data

    Science.gov (United States)

    Janiszewski, Helen Anne

    A new onshore-offshore seismic dataset from the Cascadia subduction zone was used to characterize mantle lithosphere structure from the ridge to the volcanic arc, and plate interface structure offshore within the seismogenic zone. The Cascadia Initiative (CI) covered the Juan de Fuca plate offshore the northwest coast of the United States with an ocean bottom seismometer (OBS) array for four years; this was complemented by a simultaneous onshore seismic array. Teleseismic data recorded by this array allows the unprecedented imaging of an entire tectonic plate from its creation at the ridge through subduction initiation and back beyond the volcanic arc along the entire strike of the Cascadia subduction zone. Higher frequency active source seismic data also provides constraints on the crustal structure along the plate interface offshore. Two seismic datasets were used to image the plate interface structure along a line extending 100 km offshore central Washington. These are wide-angle reflections from ship-to-shore seismic data from the Ridge-To-Trench seismic cruise and receiver functions calculated from a densely spaced CI OBS focus array in a similar region. Active source seismic observations are consistent with reflections from the plate interface offshore indicating the presence of a P-wave velocity discontinuity. Until recently, there has been limited success in using the receiver function technique on OBS data. I avoid these traditional challenges by using OBS constructed with shielding deployed in shallow water on the continental shelf. These data have quieter horizontals and avoid water- and sediment-multiple contamination at the examined frequencies. The receiver functions are consistently modeled with a velocity structure that has a low velocity zone (LVZ) with elevated P to S-wave velocity ratios at the plate interface. A similar LVZ structure has been observed onshore and interpreted as a combination of elevated pore-fluid pressures or metasediments

  5. Characterization and application of microearthquake clusters to problems of scaling, fault zone dynamics, and seismic monitoring at Parkfield, California

    Energy Technology Data Exchange (ETDEWEB)

    Nadeau, Robert Michael [Univ. of California, Berkeley, CA (United States)

    1995-10-01

    This document contains information about the characterization and application of microearthquake clusters and fault zone dynamics. Topics discussed include: Seismological studies; fault-zone dynamics; periodic recurrence; scaling of microearthquakes to large earthquakes; implications of fault mechanics and seismic hazards; and wave propagation and temporal changes.

  6. Seismic attenuation structure beneath Nazca Plate subduction zone in southern Peru

    Science.gov (United States)

    Jang, H.; Kim, Y.; Clayton, R. W.

    2017-12-01

    We estimate seismic attenuation in terms of quality factors, QP and QS using P and S phases, respectively, beneath Nazca Plate subduction zone between 10°S and 18.5°S latitude in southern Peru. We first relocate 298 earthquakes with magnitude ranges of 4.0-6.5 and depth ranges of 20-280 km. We measure t*, which is an integrated attenuation through the seismic raypath between the regional earthquakes and stations. The measured t* are inverted to construct three-dimensional attenuation structures of southern Peru. Checkerboard test results for both QP and QS structures ensure good resolution in the slab-dip transition zone between flat and normal slab subduction down to a depth of 200 km. Both QP and QS results show higher attenuation continued down to a depth of 50 km beneath volcanic arc and also beneath the Quimsachata volcano, the northernmost young volcano, located far east of the main volcanic front. We also observe high attenuation in mantle wedge especially beneath the normal subduction region in both QP and QS (100-130 in QP and 100-125 in QS) and slightly higher QP and QS beneath the flat-subduction and slab-dip transition regions. We plan to relate measured attenuation in the mantle wedge to material properties such as viscosity to understand the subduction zone dynamics.

  7. Factors influencing seismic wave attenuation in the lithosphere in continental rift zones

    Directory of Open Access Journals (Sweden)

    А. А. Dobrynina

    2017-01-01

    Full Text Available Attenuation of seismic waves in the crust and the upper mantle has been studied in three global rift systems: the Baikal rift system (Eurasia, the North Tanzanian divergence zone (Africa and the Basin and Range Province (North America. Using the records of direct and coda waves of regional earthquakes, the single scattering theory [Aki, Chouet, 1975], the hybrid model from [Zeng, 1991] and the approach described in [Wennerberg, 1993], we estimated the seismic quality factor (QC, frequency parameter (n, attenuation coefficient (δ, and total attenuation (QT. In addition, we evaluated the contributions of two components into total attenuation: intrinsic attenuation (Qi, and scattering attenuation (Qsc. Values of QC are strongly dependent on the frequency within the range of 0.2–16 Hz, as well as on the length of the coda processing window. The observed increase of QC with larger lengths of the coda processing window can be interpreted as a decrease in attenuation with increasing depth. Having compared the depth variations in the attenuation coefficient (δ and the frequency (n with the velocity structures of the studied regions, we conclude that seismic wave attenuation changes at the velocity boundaries in the medium. Moreover, the comparison results show that the estimated variations in the attenuation parameters with increasing depth are considerably dependent on utilized velocity models of the medium. Lateral variations in attenuation of seismic waves correlate with the geological and geophysical characteristics of the regions, and attenuation is primarily dependent on the regional seismic activity and regional heat flow. The geological inhomogeneities of the medium and the age of crust consolidation are secondary factors. Our estimations of intrinsic attenuation (Qi and scattering attenuation (Qsc show that in all the three studied regions, intrinsic attenuation is the major contributor to total attenuation. Our study shows that the

  8. Permeability and seismic velocity anisotropy across a ductile-brittle fault zone in crystalline rock

    Science.gov (United States)

    Wenning, Quinn C.; Madonna, Claudio; de Haller, Antoine; Burg, Jean-Pierre

    2018-05-01

    This study characterizes the elastic and fluid flow properties systematically across a ductile-brittle fault zone in crystalline rock at the Grimsel Test Site underground research laboratory. Anisotropic seismic velocities and permeability measured every 0.1 m in the 0.7 m across the transition zone from the host Grimsel granodiorite to the mylonitic core show that foliation-parallel P- and S-wave velocities systematically increase from the host rock towards the mylonitic core, while permeability is reduced nearest to the mylonitic core. The results suggest that although brittle deformation has persisted in the recent evolution, antecedent ductile fabric continues to control the matrix elastic and fluid flow properties outside the mylonitic core. The juxtaposition of the ductile strain zone next to the brittle zone, which is bounded inside the two mylonitic cores, causes a significant elastic, mechanical, and fluid flow heterogeneity, which has important implications for crustal deformation and fluid flow and for the exploitation and use of geothermal energy and geologic waste storage. The results illustrate how physical characteristics of faults in crystalline rocks change in fault zones during the ductile to brittle transitions.

  9. Monitoring deep geodynamic processes within Vrancea intermediate-depth seismic zone by geodetic means

    Science.gov (United States)

    Besutiu, Lucian; Zlagnean, Luminita

    2015-04-01

    Background Located in the bending zone of East Carpathians, the so-called Vrancea zone is one of the most active seismic regions in Europe. Despite many years of international research, its intermediate-depth seismicity within full intra-continental environment still represents a challenge of the 21st century. Infrastructure In the attempt to join the above-mentioned efforts, the Solid Earth Dynamics Department (SEDD) in the Institute of Geodynamics of the Romanian Academy has developed a special research infrastructure, mainly devoted to gravity and space geodesy observations. A geodetic network covering the epicentre area of the intermediate-depth earthquakes has been designed and implemented for monitoring deep geodynamic processes and their surface echoes. Within each base-station of the above-mentioned network, a still-reinforced concrete pillar allows for high accuracy repeated gravity and GPS determinations. Results Starting from some results of the previously run CERGOP and UNIGRACE European programmes, to which additional SEDD repeated field campaigns were added, an unusual geodynamic behaviour has been revealed in the area. 1) Crust deformation: unlike the overall uprising of East Carpathians, as a result of denudation followed by erosion, their SE bending zone, with Vrancea epicentre area exhibits a slight subsidence. 2) Gravity change: more than 200 microgals non-tidal gravity decrease over a 20 years time-span has been noticed within the subsiding area. Extended observations showed the gravity lowering as a nowadays continuing process. Interpretation This strange combination of topography subsidence and gravity lowering has been interpreted in terms of crust stretching in the Vrancea epicentre zone due to the gravity pull created by densification of the lower crust as a result of phase-transform processes taking place in the lithospheric compartment sunken into the upper mantle. The occurrence of crust earthquakes with vertical-extension focal

  10. Slow Earthquakes in the Alaska-Aleutian Subduction Zone Detected by Multiple Mini Seismic Arrays

    Science.gov (United States)

    LI, B.; Ghosh, A.; Thurber, C. H.; Lanza, F.

    2017-12-01

    The Alaska-Aleutian subduction zone is one of the most seismically and volcanically active plate boundaries on earth. Compared to other subduction zones, the slow earthquakes, such as tectonic tremors (TTs) and low frequency earthquakes (LFEs), are relatively poorly studied due to the limited data availability and difficult logistics. The analysis of two-months of continuous data from a mini array deployed in 2012 shows abundant tremor and LFE activities under Unalaska Island that is heterogeneously distributed [Li & Ghosh, 2017]. To better study slow earthquakes and understand their physical characteristics in the study region, we deployed a hybrid array of arrays, consisting of three well-designed mini seismic arrays and five stand alone stations, in the Unalaska Island in 2014. They were operational for between one and two years. Using the beam back-projection method [Ghosh et al., 2009, 2012], we detect continuous tremor activities for over a year when all three arrays are running. The sources of tremors are located south of the Unalaska and Akutan Islands, at the eastern and down-dip edge of the rupture zone of the 1957 Mw 8.6 earthquake, and they are clustered in several patches, with a gap between the two major clusters. Tremors show multiple migration patterns with propagation in both along-strike and dip directions and a wide range of velocities. We also identify tens of LFE families and use them as templates to search for repeating LFE events with the matched-filter method. Hundreds to thousands of LFEs for each family are detected and their activities are spatiotemporally consistent with tremor activities. The array techniques are revealing a near-continuous tremor activity in this area with remarkable spatiotemporal details. It helps us to better recognize the physical properties of the transition zone, provides new insights into the slow earthquake activities in this area, and explores their relation with the local earthquakes and the potential slow

  11. 3D absolute hypocentral determination - 13 years of seismicity in Ecuadorian subduction zone

    Science.gov (United States)

    Font, Yvonne; Segovia, Monica; Theunissen, Thomas

    2010-05-01

    In Ecuador, the Nazca plate is subducting beneath the North Andean Block. This subduction triggered, during the last century, 4 major earthquakes of magnitude greater than 7.7. Between 1994 and 2007, the Geophysical Institute (Escuela National Politecnica, Quito) recorded about 40 000 events in whole Ecuador ranging from Mb 1.5 to 6.9. Unfortunately, the local network shows great density discrepancy between the Coastal and Andean regions where numerous stations were installed to survey volcanic activity. Consequently, seismicity in and around the interplate seismogenic zone - producer of the most destructive earthquakes and tsunamis - is not well constrained. This study aims to improve the location of 13 years seismicity occurred during an interseismic period in order to better localize the seismic deformation and gaps. The first step consists in the construction of a 3D "georealistic" velocity model. Because local tomography cannot provide satisfactory model, we combined all local crustal/lithospheric information on the geometry and velocity properties of different geological units. Those information cover the oceanic Nazca plate and sedimentary coverture the subducting plate dip angle; the North Andean Block margin composed of accreted oceanic plateaus (the Moho depth is approximated using gravity modeling); the metamorphic volcanic chain (oceanic nature for the occidental cordillera and inter-andean valley, continental one for the oriental cordillera); The continental Guyana shield and sedimentary basins. The resulting 3D velocity model extends from 2°N to 6.5°S and 277°E to 283°E and reaches a depth of 300 km. It is discretized in constant velocity blocks of 12 x 12 x 3 km in x, y and z, respectively. The second step consists in selecting an adequate sub-set of seismic stations in order to correct the effect of station density disequilibrium between coastal and volcanic regions. Consequently, we only keep the most representative volcanic stations in terms

  12. Seismic assessment of selected buildings and equipment contents of a DOE facility in UBC zone 2A

    International Nuclear Information System (INIS)

    Tong, W.H.; Deneff, C.; Griffin, M.J.

    1991-01-01

    A preliminary seismic risk assessment for selected buildings and representative equipment contents in Allied-Signal Kansas City Division was performed to identify potential seismic hazard and weakness. The site is located in the Uniform Building Code Zone 2A. The selected building structures were constructed between 1940s to 1980s. The performance goal was to qualitatively assess the potential for loss of toxic or hazardous materials and injury to plant personnel due to an earthquake event

  13. The Sorgenfrei-Tornquist Zone as the mantle edge of Baltica lithosphere: new evidence from three-dimensional seismic anisotropy

    Czech Academy of Sciences Publication Activity Database

    Babuška, Vladislav; Plomerová, Jaroslava

    2004-01-01

    Roč. 16, č. 5 (2004), s. 243-249 ISSN 0954-4879 R&D Projects: GA AV ČR KSK3012103; GA ČR GA205/04/0748; GA AV ČR IAA3012405 Keywords : seismic experiment TOR * Trans-European Suture Zone * seismic anisotropy Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.059, year: 2004

  14. Characterizing fractures and shear zones in crystalline rock using seismic and GPR methods

    Science.gov (United States)

    Doetsch, Joseph; Jordi, Claudio; Laaksonlaita, Niko; Gischig, Valentin; Schmelzbach, Cedric; Maurer, Hansruedi

    2016-04-01

    Understanding the natural or artificially created hydraulic conductivity of a rock mass is critical for the successful exploitation of enhanced geothermal systems (EGS). The hydraulic response of fractured crystalline rock is largely governed by the spatial organization of permeable fractures. Defining the 3D geometry of these fractures and their connectivity is extremely challenging, because fractures can only be observed directly at their intersections with tunnels or boreholes. Borehole-based and tunnel-based ground-penetrating radar (GPR) and seismic measurements have the potential to image fractures and other heterogeneities between and around boreholes and tunnels, and to monitor subtle time-lapse changes in great detail. We present the analysis of data acquired in the Grimsel rock laboratory as part of the In-situ Stimulation and Circulation (ISC) experiment, in which a series of stimulation experiments have been and will be performed. The experiments in the granitic rock range from hydraulic fracturing to controlled fault-slip experiments. The aim is to obtain a better understanding of coupled seismo-hydro-mechanical processes associated with high-pressure fluid injections in crystalline rocks and their impact on permeability creation and enhancement. GPR and seismic data have been recorded to improve the geological model and characterize permeable fractures and shear zones. The acquired and processed data include reflection GPR profiles measured from tunnel walls, single-borehole GPR images, and borehole-to-borehole and tunnel-to-tunnel seismic and GPR tomograms. The reflection GPR data reveal the geometry of shear zones up to a distance of 30 m from the tunnels and boreholes, but the interpretation is complicated by the geometrical ambiguity around tunnels and boreholes and by spurious reflections from man-made structures such as boreholes. The GPR and seismic traveltime tomography results reveal brittle fractured rock between two ductile shear zones. The

  15. Seismic trapped modes in the oroville and san andreas fault zones.

    Science.gov (United States)

    Li, Y G; Leary, P; Aki, K; Malin, P

    1990-08-17

    Three-component borehole seismic profiling of the recently active Oroville, California, normal fault and microearthquake event recording with a near-fault three-component borehole seismometer on the San Andreas fault at Parkfield, California, have shown numerous instances of pronounced dispersive wave trains following the shear wave arrivals. These wave trains are interpreted as fault zone-trapped seismic modes. Parkfield earthquakes exciting trapped modes have been located as deep as 10 kilometers, as shallow as 4 kilometers, and extend 12 kilometers along the fault on either side of the recording station. Selected Oroville and Parkfield wave forms are modeled as the fundamental and first higher trapped SH modes of a narrow low-velocity layer at the fault. Modeling results suggest that the Oroville fault zone is 18 meters wide at depth and has a shear wave velocity of 1 kilometer per second, whereas at Parkfield, the fault gouge is 100 to 150 meters wide and has a shear wave velocity of 1.1 to 1.8 kilometers per second. These low-velocity layers are probably the rupture planes on which earthquakes occur.

  16. Earthquake source parameter and focal mechanism estimates for the Western Quebec Seismic Zone in eastern Canada

    Science.gov (United States)

    Rodriguez Padilla, A. M.; Onwuemeka, J.; Liu, Y.; Harrington, R. M.

    2017-12-01

    The Western Quebec Seismic Zone (WQSZ) is a 160-km-wide band of intraplate seismicity extending 500 km from the Adirondack Highlands (United States) to the Laurentian uplands (Canada). Historically, the WQSZ has experienced over fifteen earthquakes above magnitude 5, with the noteworthy MN5.2 Ladysmith event on May 17, 2013. Previous studies have associated seismicity in the area to the reactivation of Early Paleozoic normal faults within a failed Iapetan rift arm, or strength contrasts between mafic intrusions and felsic rocks due to the Mesozoic track of the Great Meteor hotspot. A good understanding of seismicity and its relation to pre-existing structures requires information about event source properties, such as static stress drop and fault plane orientation, which can be constrained via spectral analysis and focal mechanism solutions. Using data recorded by the CNSN and USArray Transportable Array, we first characterize b-value for 709 events between 2012 and 2016 in WQSZ, obtaining a value of 0.75. We then determine corner frequency and seismic moment values by fitting S-wave spectra on transverse components at all stations for 35 events MN 2.7+. We select event pairs with highly similar waveforms, proximal hypocenters, and magnitudes differing by 1-2 units. Our preliminary results using single-station spectra show corner frequencies of 15 to 40 Hz and stress drop values between 7 and 130 MPa, typical of intraplate seismicity. Last, we solve focal mechanism solutions of 35 events with impulsive P-wave arrivals at a minimum of 8 stations using the hybridMT moment tensor inversion algorithm. Our preliminary results suggest predominantly thrust faulting mechanisms, and at times oblique thrust faulting. The P-axis trend of the focal mechanism solutions suggests a principal stress orientation of NE-SW, which is consistent with that derived from focal mechanisms of earthquakes prior to 2013. We plan to fit the event pair spectral ratios to correct for attenuation

  17. Joint seismic, hydrogeological, and geomechanical investigations of a fracture zone in the Grimsel Rock Laboratory, Switzerland

    International Nuclear Information System (INIS)

    Majer, E.L.; Myer, L.R.; Peterson, J.E. Jr.; Karasaki, K.; Long, J.C.S.; Martel, S.J.; Bluemling, P.; Vomvoris, S.

    1990-06-01

    This report is one of a series documenting the results of the Nagra-DOE Cooperative (NDC-I) research program in which the cooperating scientists explore the geological, geophysical, hydrological, geochemical, and structural effects anticipated from the use of a rock mass as a geologic repository for nuclear waste. From 1987 to 1989 the United States Department of Energy (DOE) and the Swiss Cooperative for the Storage of Nuclear Waste (Nagra) participated in an agreement to carryout experiments for understanding the effect of fractures in the storage and disposal of nuclear waste. As part of this joint work field and laboratory experiments were conducted at a controlled site in the Nagra underground Grimsel test site in Switzerland. The primary goal of these experiments in this fractured granite was to determine the fundamental nature of the propagation of seismic waves in fractured media, and to relate the seismological parameters to the hydrological parameters. The work is ultimately aimed at the characterization and monitoring of subsurface sites for the storage of nuclear waste. The seismic experiments utilizes high frequency (1000 to 10,000 Hertz) signals in a cross-hole configuration at scales of several tens of meters. Two-, three-, and four-sided tomographic images of the fractures and geologic structure were produced from over 60,000 raypaths through a 10 by 21 meter region bounded by two nearly horizontal boreholes and two tunnels. Intersecting this region was a dominant fracture zone which was the target of the investigations. In addition to these controlled seismic imaging experiments, laboratory work using core from this region were studied for the relation between fracture content, saturation, and seismic velocity and attenuation. In-situ geomechanical and hydrologic tests were carried out to determine the mechanical stiffness and conductivity of the fractures. 20 refs., 90 figs., 6 tabs

  18. Characterizing potentially induced earthquake rate changes in the Brawley Seismic Zone, southern California

    Science.gov (United States)

    Llenos, Andrea L.; Michael, Andrew J.

    2016-01-01

    The Brawley seismic zone (BSZ), in the Salton trough of southern California, has a history of earthquake swarms and geothermal energy exploitation. Some earthquake rate changes may have been induced by fluid extraction and injection activity at local geothermal fields, particularly at the North Brawley Geothermal Field (NBGF) and at the Salton Sea Geothermal Field (SSGF). We explore this issue by examining earthquake rate changes and interevent distance distributions in these fields. In Oklahoma and Arkansas, where considerable wastewater injection occurs, increases in background seismicity rate and aftershock productivity and decreases in interevent distance were indicative of fluid‐injection‐induced seismicity. Here, we test if similar changes occur that may be associated with fluid injection and extraction in geothermal areas. We use stochastic epidemic‐type aftershock sequence models to detect changes in the underlying seismogenic processes, shown by statistically significant changes in the model parameters. The most robust model changes in the SSGF roughly occur when large changes in net fluid production occur, but a similar correlation is not seen in the NBGF. Also, although both background seismicity rate and aftershock productivity increased for fluid‐injection‐induced earthquake rate changes in Oklahoma and Arkansas, the background rate increases significantly in the BSZ only, roughly corresponding with net fluid production rate increases. Moreover, in both fields the interevent spacing does not change significantly during active energy projects. This suggests that, although geothermal field activities in a tectonically active region may not significantly change the physics of earthquake interactions, earthquake rates may still be driven by fluid injection or extraction rates, particularly in the SSGF.

  19. Fractal properties and simulation of micro-seismicity for seismic hazard analysis: a comparison of North Anatolian and San Andreas Fault Zones

    Directory of Open Access Journals (Sweden)

    Naside Ozer

    2012-02-01

    Full Text Available We analyzed statistical properties of earthquakes in western Anatolia as well as the North Anatolian Fault Zone (NAFZ in terms of spatio-temporal variations of fractal dimensions, p- and b-values. During statistically homogeneous periods characterized by closer fractal dimension values, we propose that occurrence of relatively larger shocks (M >= 5.0 is unlikely. Decreases in seismic activity in such intervals result in spatial b-value distributions that are primarily stable. Fractal dimensions decrease with time in proportion to increasing seismicity. Conversely, no spatiotemporal patterns were observed for p-value changes. In order to evaluate failure probabilities and simulate earthquake occurrence in the western NAFZ, we applied a modified version of the renormalization group method. Assuming an increase in small earthquakes is indicative of larger shocks, we apply the mentioned model to micro-seismic (M<= 3.0 activity, and test our results using San Andreas Fault Zone (SAFZ data. We propose that fractal dimension is a direct indicator of material heterogeneity and strength. Results from a model suggest simulated and observed earthquake occurrences are coherent, and may be used for seismic hazard estimation on creeping strike-slip fault zones.

  20. Quaternary layer anomalies around the Carlsberg Fault zone mapped with high-resolution shear-wave seismics south of Copenhagen

    DEFF Research Database (Denmark)

    Kammann, Janina; Hübscher, Christian; Nielsen, Lars

    Fault zone. The portable compact vibrator source ElViS III S8 was used to acquire a 1150 m long seismic section on the island Amager, south of Copenhagen. The shallow subsurface in the investigation area is dominated by Quaternary glacial till deposits in the upper 5-11 m and Danian limestone below....... In the shear-wave profile, we imaged the 30 m of the upward continuation of the Carlsberg Fault zone. In our area of investigation, the fault zone appears to comprise normal block faults and one reverse block fault showing the complexity of the fault zone. The observed faults appear to affect both the Danian...

  1. Workshop on New Madrid geodesy and the challenges of understanding intraplate earthquakes

    Science.gov (United States)

    Boyd, Oliver; Calais, Eric; Langbein, John; Magistrale, Harold; Stein, Seth; Zoback, Mark

    2013-01-01

    On March 4, 2011, 26 researchers gathered in Norwood, Massachusetts, for a workshop sponsored by the U.S. Geological Survey and FM Global to discuss geodesy in and around the New Madrid seismic zone (NMSZ) and its relation to earthquake hazard. The group addressed the challenge of reconciling current geodetic measurements, which show low present-day surface strain rates, with paleoseismic evidence of recent, relatively frequent, major earthquakes in the region. Several researchers were invited by the organizing committee to give overview presentations while all participants were encouraged to present their most recent ideas. The overview presentations appear in this report along with a set of recommendations.

  2. Spatial Relationship Between Crustal Structure and Mantle Seismicity in the Vrancea Seismogenic Zone of Romania

    Science.gov (United States)

    Knapp, C. C.; Enciu, D. M.; Knapp, J. H.

    2007-12-01

    Active crustal deformation and subsidence in the Southeast Carpathian foreland has previously been attributed to active foundering of thickened continental lithosphere beneath the Carpathian bend region (Knapp et al, 2005). The present study involves integration of active and passive-source seismic data in order to place constraints on the duration, timing, and scale of crustal deformation in the Carpathian foreland, and in particular to assess the genetic relationship with the Vrancea intermediate-depth seismogenic zone (VSZ). Relocated crustal earthquakes and focal mechanisms were correlated with four deep industry seismic profiles, the reprocessed DACIA PLAN deep seismic profile, and the DRACULA (Deep Reflection Acquisition Constraining Unusual Lithospheric Activity) II and III profiles. Projection of foreland crustal hypocenters onto the deep seismic lines correlates well with previously identified crustal faults such as the Trotus and Sinaia, as well as the newly identified Ialomita Fault. Specifically, results of this study (1) image the full crustal and uppermost mantle structure of the Focsani Basin in the close proximity of the VSZ, (2) show evidence for a sub-horizontal, slightly east-dipping Moho in the vicinity of the VSZ and thinning of the crust towards the Carpathian orogen, (3) illustrate the conspicuous absence of west-dipping fabrics or structures in the crust and across the Moho, (4) present evidence that the Trotus Fault is a crustal-scale active fault with a dextral sense of motion, (5) suggest that the Paleozoic age Peceneaga-Camena and Capidava-Ovidiu Faults have not been active in post-Paleozoic time, and (6) show evidence for a new active crustal scale sinistral fault, named the Ialomita fault. Both the seismogenic Vrancea body and deformation in the Focsani Basin appear to be concentrically bound by the Trotus Fault in the north and east and the Sinaia-Ialomita Fault in the south, suggesting a coupled deformation between the VSZ and the

  3. Seismic Attenuation Tomography of the Rupture Zone of the 2010 Maule, Chile, Earthquake

    Science.gov (United States)

    Torpey, M. E.; Russo, R. M.; Panning, M. P.

    2014-12-01

    We used measurements of differential S to P seismic attenuation in the rupture zone of the 2010 Mw 8.8 Maule, Chile earthquake (33°S-38°S) to characterize the seismic attenuation structure of the South American crust and upper mantle wedge. We used data obtained from the IRIS CHAMP rapid-response temporary seismic network, filtered between 0.7-20 Hz. For events with large signal to noise ratios, we visually identified the P and S arrivals on the seismograms and used an evolving time window to determine 400 individual Qs and t* values and their uncertainties using a spectral ratio method. Using a phase pair method allows us to neglect the source-time function and instrument response of each P-S phase pair. Assuming a constant Qp/Qs ratio for a given P-S phase pair, we evaluated the 400 spectral ratios and discarded portions of the evolving time window that incorporate multipathed phases. We recalculated the Qs and standard deviation of the retained window and excluded measurements with standard deviations larger than half of the Qs value. We also excluded measurements that span frequency windows longer than 10 Hz as they contain noise that contaminates Qs measurements. We examined ~200 local events yielding a total of 1,076 path-integrated Q­s measurements. Qs values are low (100-400) for the majority of ray paths evaluated, however we observe a spatial distribution of low path-integrated Qs values (100-300) in the northeastern portion of the rupture zone and higher values (300-600) in the southwest. We divided the rupture zone into cubes and implemented a bounded linear inequality least squares inversion (0

  4. Automatic picking of direct P, S seismic phases and fault zone head waves

    Science.gov (United States)

    Ross, Z. E.; Ben-Zion, Y.

    2014-10-01

    We develop a set of algorithms for automatic detection and picking of direct P and S waves, as well as fault zone head waves (FZHW), generated by earthquakes on faults that separate different lithologies and recorded by local seismic networks. The S-wave picks are performed using polarization analysis and related filters to remove P-wave energy from the seismograms, and utilize STA/LTA and kurtosis detectors in tandem to lock on the phase arrival. The early portions of P waveforms are processed with STA/LTA, kurtosis and skewness detectors for possible first-arriving FZHW. Identification and picking of direct P and FZHW is performed by a multistage algorithm that accounts for basic characteristics (motion polarities, time difference, sharpness and amplitudes) of the two phases. The algorithm is shown to perform well on synthetic seismograms produced by a model with a velocity contrast across the fault, and observed data generated by earthquakes along the Parkfield section of the San Andreas fault and the Hayward fault. The developed techniques can be used for systematic processing of large seismic waveform data sets recorded near major faults.

  5. Enriquillo–Plantain Garden fault zone in Jamaica: paleoseismology and seismic hazard

    Science.gov (United States)

    Koehler, R.D.; Mann, P.; Prentice, Carol S.; Brown, L.; Benford, B.; Grandison-Wiggins, M.

    2013-01-01

    The countries of Jamaica, Haiti, and the Dominican Republic all straddle the Enriquillo–Plantain Garden fault zone ( EPGFZ), a major left-lateral, strike-slip fault system bounding the Caribbean and North American plates. Past large earthquakes that destroyed the capital cities of Kingston, Jamaica (1692, 1907), and Port-au-Prince, Haiti (1751, 1770), as well as the 2010 Haiti earthquake that killed more than 50,000 people, have heightened awareness of seismic hazards in the northern Caribbean. We present here new geomorphic and paleoseismic information bearing on the location and relative activity of the EPGFZ, which marks the plate boundary in Jamaica. Documentation of a river bank exposure and several trenches indicate that this fault is active and has the potential to cause major destructive earthquakes in Jamaica. The results suggest that the fault has not ruptured the surface in at least 500 yr and possibly as long as 28 ka. The long period of quiescence and subdued geomorphic expression of the EPGFZ indicates that it may only accommodate part of the ∼7–9 mm=yr plate deformation rate measured geodetically and that slip may be partitioned on other undocumented faults. Large uncertainties related to the neotectonic framework of Jamaica remain and more detailed fault characterization studies are necessary to accurately assess seismic hazards.

  6. Making the most of CZ seismics: Improving shallow critical zone characterization using surface-wave analysis

    Science.gov (United States)

    Pasquet, S.; Wang, W.; Holbrook, W. S.; Bodet, L.; Carr, B.; Flinchum, B. A.

    2017-12-01

    Estimating porosity and saturation in the shallow subsurface over large lateral scales is vitally important for understanding the development and evolution of the Critical Zone (CZ). Because elastic properties (P- and S-wave velocities) are particularly sensitive to porosity and saturation, seismic methods (in combination with petrophysical models) are effective tools for mapping CZ architecture and processes. While many studies employ P-wave refraction methods, fewer use the surface waves that are typically also recorded in those same surveys. Here we show the value of exploiting surface waves to extract supplementary shear-wave velocity (Vs) information in the CZ. We use a new, user-friendly, open-source MATLAB-based package (SWIP) to invert surface-wave data and estimate lateral variations of Vs in the CZ. Results from synthetics show that this approach enables the resolution of physical property variations in the upper 10-15 m below the surface with lateral scales of about 5 m - a vast improvement compared to P-wave tomography alone. A field example at a Yellowstone hydrothermal system also demonstrates the benefits of including Vs in the petrophysical models to estimate not only porosity but also saturation, thus highlighting subsurface gas pathways. In light of these results, we strongly suggest that surface-wave analysis should become a standard approach in CZ seismic surveys.

  7. Cost reduction for large turbine generator Pedestal in high seismic zone

    International Nuclear Information System (INIS)

    Sawhney, P.S.; Irani, P.; Pusheck, B.N.

    1985-01-01

    Turbine Generator Pedestals have generally been designed using reinforced concrete. For present day large turbine generators (1100 MWe class and above) with tall (about 80 feet) pedestals, the amount of reinforcing steel becomes quite large, especially for plants in high seismic zones. With the prime objective of cost reduction, an approach using steel/concrete composite design has been studied for a large BWR Turbine Generator pedestal with 0.3g peak ground acceleration. Large prefabricated steel modules were adopted for composite design and simplified construction. Design was based on the ACI and AISC codes. Costs and schedules were developed and compared with those for a conventionally designed reinforced concrete pedestal. Composite design was found to give considerable cost and schedule advantage over the conventional reinforced concrete design

  8. Seismic Investigations of an Accommodation zone in the Northern Rio Grande Rift, New Mexico, USA

    Science.gov (United States)

    Baldridge, W. S.; Valdes, J.; Nedorub, O.; Phrampus, B.; Braile, L. W.; Ferguson, J. F.; Benage, M. C.; Litherland, M.

    2010-12-01

    Seismic reflection and refraction data acquired in the Rio Grande rift near Santa Fe, New Mexico, in 2009 and 2010 by the SAGE (Summer of Applied Geophysical Experience) program imaged the La Bajada fault (LBF) and strata offset across the associated, perpendicular Budagher fault (BF). The LBF is a major basin-bounding normal fault, offset down to the west; the smaller BF is an extensional fault that breaks the hanging wall ramp of the LBF. We chose this area because it is in a structurally complex region of the rift, comprising a small sub-basin and plunging relay ramps, where north-trending, en echelon basin-bounding faults (including the LBF) transfer crustal extension laterally between the larger Española (to north) and Albuquerque rift basins. Our data help determine the precise location and geometry of the poorly exposed LBF, which, near the survey location, offsets the rift margin vertically about 3,000 m. When integrated with industry reflection data and other SAGE seismic, gravity, and magnetotelluric surveys, we are able to map differences in offset and extension laterally (especially southward) along the fault. We interpret only about 200 m of normal offset across the BF. Our continuing work helps define multiple structural elements, partly buried by syn-rift basin-filling sedimentary rocks, of a complex intra-rift accommodation zone. We are also able to discriminate pre-Eocene (Laramide) from post-Miocene (rift) structures. Our data help determine the amount of vertical offset of pre-rift strata across structural elements of the accommodation zone, and depth and geometry of basin fill. A goal is to infer the kinematic development of this margin of the rift, linkages among faults, growth history, and possible pre-rift structural controls. This information will be potentially useful for evaluation of resources, including oil and/or gas in pre-rift strata and ground water in Late Miocene to Holocene rift-filling units.

  9. Seismically active column and volcanic plumbing system beneath the island arc of the Izu-Bonin subduction zone

    Czech Academy of Sciences Publication Activity Database

    Špičák, Aleš; Vaněk, Jiří; Hanuš, Václav

    2009-01-01

    Roč. 179, č. 3 (2009), s. 1301-1312 ISSN 0956-540X Institutional research plan: CEZ:AV0Z30120515 Keywords : seismicity and tectonics * volcano seismology * subduction zone processes * volcanic arc processes * magma migration and fragmentation * Pacific Ocean Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.435, year: 2009

  10. Seismicity and Seismotectonic Properties of The Sultandağı Fault Zone (Afyonkarahisar-Konya): Western Anatolia,Turkey

    Science.gov (United States)

    Kalafat, D.; Gunes, Y.; Kekovali, K.; Kara, M.; Gorgun, E.

    2017-12-01

    n this study we investigated seismicity and source characteristics of the Sultandağı Fault Zone (SFZ). As known Western Anatolia is one of the most important seismically active region in Turkey. The relative movement of the African-Arabian plates, it causes the Anatolian Plate to movement to the west-Southwest direction 2.5 cm per year and this result provides N-S direction with extensional regime in the recent tectonic. In this study, especially with the assessment of seismic activity occurring in Afyon and around between 200-2002 years, we have been evaluated to date with seismic activity as well as fault mechanism solution. We analyzed recent seismicity and distribution of earthquakes in this region. In the last century, 3 important earthquakes occurred in the Sultandağı Fault zone (Afyon-Akşehir Graben), this result shown it was seismic active and broken fault segments caused stress balance in the region and it caused to occur with short intervals of earthquakes in 2000 and 2002, triggering each other. The scope of this tudy, we installed new BB stations in the region and we have been done of the fault plane solutions for important earthquakes. The focal mechanisms clearly exhibit the activation of a NE-SW trending normal faulting system along the SFZ region. The results of stress analysis showed that the effective current tectonic evolution of normal faulting in this region. This study is supported by Bogazici University Research Projects Commission under SRP/BAP project No. 12280. Key Words: Sultandağı fault zone, normal faulting, seismicity, fault mechanism

  11. Study of time dynamics of seismicity for the Mexican subduction zone by means of the visibility graph method.

    Science.gov (United States)

    Ramírez-Rojas, Alejandro; Telesca, Luciano; Lovallo, Michele; Flores, Leticia

    2015-04-01

    By using the method of the visibility graph (VG), five magnitude time series extracted from the seismic catalog of the Mexican subduction zone were investigated. The five seismic sequences represent the seismicity which occurred between 2005 and 2012 in five seismic areas: Guerrero, Chiapas, Oaxaca, Jalisco and Michoacan. Among the five seismic sequences, the Jalisco sequence shows VG properties significantly different from those shown by the other four. Such a difference could be inherent in the different tectonic settings of Jalisco with respect to those characterizing the other four areas. The VG properties of the seismic sequences have been put in relationship with the more typical seismological characteristics (b-value and a-value of the Gutenberg-Richter law). The present study was supported by the Bilateral Project Italy-Mexico "Experimental Stick-slip models of tectonic faults: innovative statistical approaches applied to synthetic seismic sequences", jointly funded by MAECI (Italy) and AMEXCID (Mexico) in the framework of the Bilateral Agreement for Scientific and Technological Cooperation PE 2014-2016

  12. Spatial relationships between crustal structures and mantle seismicity in the Vrancea Seismogenic Zone of Romania: Implications for geodynamic evolution

    Science.gov (United States)

    Enciu, Dana-Mihaela

    Integration of active and passive-source seismic data is employed to study the relationships between crustal structures and seismicity in the SE Carpathian foreland of Romania, and the connection with the Vrancea Seismogenic Zone. Relocated crustal epicenters and focal mechanisms are correlated with industry seismic profiles Comanesti, Ramnicu Sarat, Braila and Buzau, the reprocessed DACIA PLAN profile and the DRACULA (Deep Reflection Acquisition Constraining Unusual Lithospheric Activity) II and III profiles in order to understand the link between neo-tectonic foreland deformation and Vrancea mantle seismicity. Projection of crustal foreland hypocenters onto deep seismic profiles identified active crustal faults suggesting a mechanical coupling between sedimentary, crustal and upper mantle structures on the Trotus, Sinaia and newly observed Ialomita Faults. Seismic reflection imaging revealed the absence of west dipping reflectors in the crust and an east dipping to horizontal Moho in the proximity of the Vrancea area. These findings argue against both 'subduction-in-place' and 'slab break-off' as viable mechanisms for generating Vrancea mantle seismicity.

  13. Near-surface structural model for deformation associated with the February 7, 1812, New Madrid, Missouri, earthquake

    Science.gov (United States)

    Odum, J.K.; Stephenson, W.J.; Shedlock, K.M.; Pratt, T.L.

    1998-01-01

    The February 7, 1812, New Madrid, Missouri, earthquake (M [moment magnitude] 8) was the third and final large-magnitude event to rock the northern Mississippi Embayment during the winter of 1811-1812. Although ground shaking was so strong that it rang church bells, stopped clocks, buckled pavement, and rocked buildings up and down the eastern seaboard, little coseismic surface deformation exists today in the New Madrid area. The fault(s) that ruptured during this event have remained enigmatic. We have integrated geomorphic data documenting differential surficial deformation (supplemented by historical accounts of surficial deformation and earthquake-induced Mississippi River waterfalls and rapids) with the interpretation of existing and recently acquired seismic reflection data, to develop a tectonic model of the near-surface structures in the New Madrid, Missouri, area. This model consists of two primary components: a northnorthwest-trending thrust fault and a series of northeast-trending, strike-slip, tear faults. We conclude that the Reelfoot fault is a thrust fault that is at least 30 km long. We also infer that tear faults in the near surface partitioned the hanging wall into subparallel blocks that have undergone differential displacement during episodes of faulting. The northeast-trending tear faults bound an area documented to have been uplifted at least 0.5 m during the February 7, 1812, earthquake. These faults also appear to bound changes in the surface density of epicenters that are within the modern seismicity, which is occurring in the stepover zone of the left-stepping right-lateral strike-slip fault system of the modern New Madrid seismic zone.

  14. Examining seismicity patterns in the 2010 M 8.8 Maule rupture zone.

    Science.gov (United States)

    Diniakos, R. S.; Bilek, S. L.; Rowe, C. A.; Draganov, D.

    2016-12-01

    The subduction of the Nazca Plate beneath the South American Plate along Chile has produced some of the largest earthquakes recorded on modern seismic instrumentation. These include the 1960 M 9.5 Valdivia, 2010 M 8.8 Maule, 2014 M 8.1 Iquique, and more recently the 2015 M 8.3 Illapel earthquakes. Slip heterogeneity in the 2010 Maule earthquake has been noted in various studies, with bilateral slip and peak slip of 15 m north of the epicenter. For other great subduction zone earthquakes, such as the 2004 M 9.1 Sumatra, 2010 M 8.8 Maule, and 2011 M 9.0 Tohoku, there was an increase in normal-faulting earthquakes in regions of high slip. In order to understand aftershock behavior of the 2010 Maule event, we are expanding the catalog of small magnitude earthquakes using a template-matching algorithm to find other small earthquakes in the rupture area. We use a starting earthquake catalog (magnitudes between 2.5-4.0) developed from regional and local array seismic data; these comprise our template catalog from Jan. - Dec. 2012 that we use to search through seismic waveforms recorded by a 2012 temporary seismic array in Malargüe, Argentina located 300 km east of the Maule rupture area. We use waveform cross correlation techniques in order to detect new events, and then we use HYPOINVERSE2000 (Klein, 2002) and a velocity model designed for the south-central Chilean region (Haberland et al., 2006) to locate new detections. We also determine focal mechanisms to further analyze aftershock behavior for the region. To date, over 2400 unique detections have been found, of which we have located 133 events with an RMS <1. Many of these events are located in the region of greatest coseismic slip, north of the 2010 epicenter, whereas catalog events are located north and south of the epicenter, along the regions of bilateral slip. Focal mechanisms for the new locations will also be presented.

  15. Study of modern seismic zoning maps' accuracy (case for Eastern Uzbekistan

    Directory of Open Access Journals (Sweden)

    T.U. Artikov

    2016-11-01

    Full Text Available Influence of uncertainty factors of input parameters on results of the estimation of seismic hazard has been researched. It is found that the largest deviations, from seismic hazard maps designed on the basis of average values of distribution of seismic mode and seismic load parameters, may arise due to the imprecise depth of earthquake sources (H, uncertain estimations of seismic potential (Мmax and slope of recurrence curve (γ. The contribution of such uncertainty factors, like imprecise definition of seismic activity А10, incorrect choice of prevailing type of a motion in the source, using regional laws of attenuation of seismic load intensity in distance instead of local once are substantially small. For Eastern Uzbekistan, it was designed the seismic hazard map with the highest value which takes into account every possible factors of uncertainty in parameters of seismic mode and seismic load.

  16. Complex plume dynamics in the transition zone underneath the Hawaii hotspot: seismic imaging results

    Science.gov (United States)

    Cao, Q.; van der Hilst, R. D.; de Hoop, M. V.; Shim, S.

    2010-12-01

    In recent years, progress has been made in seismology to constrain the depth variations of the transition zone discontinuities, e.g. 410 km and 660 km discontinuities, which can be used to constrain the local temperature and chemistry profiles, and hence to infer the existences and morphology of mantle plumes. Taking advantage of the abundance of natural earthquake sources in western Pacific subduction zones and the many seismograph stations in the Americas, we used a generalized Radon transform (GRT), a high resolution inverse-scattering technique, of SS precursors to form 3-D images of the transition zone structures of a 30 degree by 40 degree area underneath Hawaii and the Hawaii-Emperor seamount chain. Rather than a simple mushroom-shape plume, our seismic images suggest complex plume dynamics interacting with the transition zone phase transitions, especially at the 660’ discontinuity. A conspicuous uplift of the 660 discontinuity in a region of 800km in diameter is observed to the west of Hawaii. No correspondent localized depression of the 410 discontinuity is found. This lack of correlation between and differences in lateral length scale of the topographies of the 410 and 660 km discontinuities are consistent with many geodynamical modeling results, in which a deep-mantle plume impinging on the transition zone, creating a pond of hot material underneath endothermic phase change at 660 km depth, and with secondary plumes connecting to the present-day hotspot at Earth’s surface. This more complex plume dynamics suggests that the complicated mass transport process across the transition zone should be taken into account when we try to link the geochemical observations of Hawaiian basalt geochemistry at the Earth’s surface to deep mantle domains. In addition to clear signals at 410km, 520km and 660km depth, the data also reveals rich structures near 350km depth and between 800 - 1000km depth, which may be regional, laterally intermittent scatter interfaces

  17. The Oldman River triangle zone: a complicated tectonic wedge delineated by new structural mapping and seismic interpretation

    Energy Technology Data Exchange (ETDEWEB)

    Stockmal, G. S. [Geological Survey of Canada, Calgary, AB (Canada). Inst. of Sedimentary and Petroleum Geology; Lawton, D. C.; Spratt, D. [Calgary Univ., AB (Canada). Dept. of Geology and Geophysics; MacKay, P. A.

    1996-06-01

    The triangle zone exposed along and adjacent to the Alberta Foothills was characterized on the basis of new structural mapping and seismic surveys. Results indicate that the zone is comprised of a complicated structure involving significant deformation in the hanging wall of the upper detachment, including orogenic thrusts and large orogen-vergent folds, as well as secondary orogen-directed tectonic wedging. This structure is considered to be an example of a `nested` triangle zone, where an `outer` tectonic wedge with modest shortening encases an `inner` counterpart with substantially more shortening. Both of these wedges show evidence of synchronous deformation. 23 refs., 9 figs.

  18. Interseismic Coupling, Co- and Post-seismic Slip: a Stochastic View on the Northern Chilean Subduction Zone

    Science.gov (United States)

    Jolivet, R.; Duputel, Z.; Simons, M.; Jiang, J.; Riel, B. V.; Moore, A. W.; Owen, S. E.

    2017-12-01

    Mapping subsurface fault slip during the different phases of the seismic cycle provides a probe of the mechanical properties and the state of stress along these faults. We focus on the northern Chile megathrust where first order estimates of interseismic fault locking suggests little to no overlap between regions slipping seismically versus those that are dominantly aseismic. However, published distributions of slip, be they during seismic or aseismic phases, rely on unphysical regularization of the inverse problem, thereby cluttering attempts to quantify the degree of overlap between seismic and aseismic slip. Considering all the implications of aseismic slip on our understanding of the nucleation, propagation and arrest of seismic ruptures, it is of utmost importance to quantify our confidence in the current description of fault coupling. Here, we take advantage of 20 years of InSAR observations and more than a decade of GPS measurements to derive probabilistic maps of inter-seismic coupling, as well as co-seismic and post-seismic slip along the northern Chile subduction megathrust. A wide InSAR velocity map is derived using a novel multi-pixel time series analysis method accounting for orbital errors, atmospheric noise and ground deformation. We use AlTar, a massively parallel Monte Carlo Markov Chain algorithm exploiting the acceleration capabilities of Graphic Processing Units, to derive the probability density functions (PDF) of slip. In northern Chile, we find high probabilities for a complete release of the elastic strain accumulated since the 1877 earthquake by the 2014, Iquique earthquake and for the presence of a large, independent, locked asperity left untapped by recent events, north of the Mejillones peninsula. We evaluate the probability of overlap between the co-, inter- and post-seismic slip and consider the potential occurrence of slow, aseismic slip events along this portion of the subduction zone.

  19. Seismic anisotropy in localized shear zones versus distributed tectonic fabrics: examples from geologic and seismic observations in western North America and the European Alps

    Science.gov (United States)

    Mahan, Kevin H.; Schulte-Pelkum, Vera; Condit, Cailey; Leydier, Thomas; Goncalves, Philippe; Raju, Anissha; Brownlee, Sarah; Orlandini, Omero F.

    2017-04-01

    Modern methods for detecting seismic anisotropy offer an array of promising tools for imaging deep crustal deformation but also present challenges, especially with respect to potential biases in both the detection methods themselves as well as in competing processes for localized versus distributed deformation. We address some of these issues from the geophysical perspective by employing azimuthally dependent amplitude and polarity variations in teleseismic receiver functions combined with a compilation of published rock elasticity tensors from middle and deep crustal rocks, and from the geological perspective through studies of shear zone deformation processes. Examples are highlighted at regional and outcrop scales from western North America and the European Alps. First, in regional patterns, strikes of seismically detected fabric from receiver functions in California show a strong alignment with current strike-slip motion between the Pacific and North American plates, with high signal strength near faults and from depths below the brittle-ductile transition suggesting these faults have deep ductile roots. In contrast, despite NE-striking shear zones being the most prominent features portrayed on Proterozoic tectonic maps of the southwestern USA, receiver function anisotropy from the central Rocky Mountain region appears to more prominently reflect broadly distributed Proterozoic fabric domains that preceded late-stage localized shear zones. Possible causes for the discrepancy fall into two categories: those that involve a) bias in seismic sampling and/or b) deformation processes that lead to either weaker anisotropy in the shear zones compared to adjacent domains or to a symmetry that is different from that conventionally assumed. Most of these explanations imply that the seismically sampled domains contain important structural information that is distinct from the shear zones. The second set of examples stem from studies of outcrop-scale shear zones in upper

  20. Fault zone identification in the eastern part of the Persian Gulf based on combined seismic attributes

    Science.gov (United States)

    Mirkamali, M. S.; Keshavarz FK, N.; Bakhtiari, M. R.

    2013-02-01

    Faults, as main pathways for fluids, play a critical role in creating regions of high porosity and permeability, in cutting cap rock and in the migration of hydrocarbons into the reservoir. Therefore, accurate identification of fault zones is very important in maximizing production from petroleum traps. Image processing and modern visualization techniques are provided for better mapping of objects of interest. In this study, the application of fault mapping in the identification of fault zones within the Mishan and Aghajari formations above the Guri base unconformity surface in the eastern part of Persian Gulf is investigated. Seismic single- and multi-trace attribute analyses are employed separately to determine faults in a vertical section, but different kinds of geological objects cannot be identified using individual attributes only. A mapping model is utilized to improve the identification of the faults, giving more accurate results. This method is based on combinations of all individual relevant attributes using a neural network system to create combined attributes, which gives an optimal view of the object of interest. Firstly, a set of relevant attributes were separately calculated on the vertical section. Then, at interpreted positions, some example training locations were manually selected in each fault and non-fault class by an interpreter. A neural network was trained on combinations of the attributes extracted at the example training locations to generate an optimized fault cube. Finally, the results of the fault and nonfault probability cube were estimated, which the neural network applied to the entire data set. The fault probability cube was obtained with higher mapping accuracy and greater contrast, and with fewer disturbances in comparison with individual attributes. The computed results of this study can support better understanding of the data, providing fault zone mapping with reliable results.

  1. Fault zone identification in the eastern part of the Persian Gulf based on combined seismic attributes

    International Nuclear Information System (INIS)

    Mirkamali, M S; Keshavarz FK, N; Bakhtiari, M R

    2013-01-01

    Faults, as main pathways for fluids, play a critical role in creating regions of high porosity and permeability, in cutting cap rock and in the migration of hydrocarbons into the reservoir. Therefore, accurate identification of fault zones is very important in maximizing production from petroleum traps. Image processing and modern visualization techniques are provided for better mapping of objects of interest. In this study, the application of fault mapping in the identification of fault zones within the Mishan and Aghajari formations above the Guri base unconformity surface in the eastern part of Persian Gulf is investigated. Seismic single- and multi-trace attribute analyses are employed separately to determine faults in a vertical section, but different kinds of geological objects cannot be identified using individual attributes only. A mapping model is utilized to improve the identification of the faults, giving more accurate results. This method is based on combinations of all individual relevant attributes using a neural network system to create combined attributes, which gives an optimal view of the object of interest. Firstly, a set of relevant attributes were separately calculated on the vertical section. Then, at interpreted positions, some example training locations were manually selected in each fault and non-fault class by an interpreter. A neural network was trained on combinations of the attributes extracted at the example training locations to generate an optimized fault cube. Finally, the results of the fault and nonfault probability cube were estimated, which the neural network applied to the entire data set. The fault probability cube was obtained with higher mapping accuracy and greater contrast, and with fewer disturbances in comparison with individual attributes. The computed results of this study can support better understanding of the data, providing fault zone mapping with reliable results. (paper)

  2. Evidence of Enhanced Subrosion in a Fault Zone and Characterization of Hazard Zones with Elastic Parameters derived from SH-wave reflection Seismics and VSP

    Science.gov (United States)

    Wadas, S. H.; Tanner, D. C.; Tschache, S.; Polom, U.; Krawczyk, C. M.

    2017-12-01

    Subrosion, the dissolution of soluble rocks, e.g., sulfate, salt, or carbonate, requires unsaturated water and fluid pathways that enable the water to flow through the subsurface and generate cavities. Over time, different structures can occur that depend on, e.g., rock solubility, flow rate, and overburden type. The two main structures are sinkholes and depressions. To analyze the link between faults, groundwater flow, and soluble rocks, and to determine parameters that are useful to characterize hazard zones, several shear-wave (SH) reflection seismic profiles were surveyed in Thuringia in Germany, where Permian sulfate rocks and salt subcrop close to the surface. From the analysis of the seismic sections we conclude that areas affected by tectonic deformation phases are prone to enhanced subrosion. The deformation of fault blocks leads to the generation of a damage zone with a dense fracture network. This increases the rock permeability and thus serves as a fluid pathway for, e.g., artesian-confined groundwater. The more complex the fault geometry and the more interaction between faults, the more fractures are generated, e.g., in a strike slip-fault zone. The faults also act as barriers for horizontal groundwater flow perpendicular to the fault surfaces and as conduits for groundwater flow along the fault strike. In addition, seismic velocity anomalies and attenuation of seismic waves are observed. Low velocities high attenuation may indicate areas affected by subrosion. Other parameters that characterize the underground stability are the shear modulus and the Vp/Vs ratio. The data revealed zones of low shear modulus high Vp/Vs ratio >2.5, which probably indicate unstable areas due to subrosion. Structural analysis of S-wave seismics is a valuable tool to detect near-surface faults in order to determine whether or not an area is prone to subrosion. The recognition of even small fault blocks can help to better understand the hydrodynamic groundwater conditions

  3. Using thermodynamic data to reproduce main seismic features of transition zone

    Science.gov (United States)

    Fomin, Ilya; Saukko, Anna; Edwards, Paul; Schiffer, Christian

    2016-04-01

    Most of the seismic tomography studies nowadays are based on comprehensive models with optimization of lots of parameters. These models are able to resolve very subtle features of the Earth's mantle, but the influence of each specific parameter is not seen directly. In our research we try to minimize the number of processed parameters to produce simple synthetic cases. The main goals of our model are to see how water content influences the depth of the transition zone, and if melting at the transition zone is plausible. We also attempt to see how water content and the presence of melts influence the signal strength of the transition zone in receiver functions. Our MATLAB-code calculates phase assemblage according to specific temperature and pressure within 2D numerical domain (e.g. 300x700 km). Phase properties are calculated with database of Stixrude and Lithgow-Bertelloni [2011], with corrections for water impact on elastic constants according to Liu et al., [2012]. We use the mantle phase composition 55% garnet and 45% olivine-polymorph, soliduses by Ohtani et al. [2004] and melt properties by Sakamaki et al. [2006]. These data are used to calculate seismic velocities and, furthermore, receiver functions with standard routines (e.g.[Schiffer et al., 2012]). Model predicts Vs within 5 to 5.5 km/s and Vp around 9.5-10 km/s within transition zone (Vp/Vs = 1.84-1.87), which is close to standard values. The presence of water enlarges the wadsleyite region, but also dampens the peak of receiver functions down to background level. Increase in water content causes melting at much shallower depths. Using a normal thermal gradient, we can get up to 10% of melt at depths around 390 km with 80% of water saturation, shown by a negative anomaly on receiver functions. This result is similar to data obtained for Afar Plateau [Thompson et al., 2015]. With cratonic thermal gradient, the olivine-wadsleyite transition and corresponding melt layer appear at depths around 350 km

  4. Investigation of the crustal and deep structure in Vrancea seismic zone

    International Nuclear Information System (INIS)

    Popa, Mihaela; Radulian, Mircea; Popescu, Emilia; Bazacliu, Olivia; Grecu, Bogdan; Ardeleanu Luminita; Ionescu, Constantin; Ivan, Marian; Dumitru, Ion; Rizescu, Mihaela

    2002-01-01

    The Vrancea zone, located at the sharp bend of the Southeast Carpathians, is characterized by an unusually narrow volume of intense seismicity (four shocks with magnitude greater than 7 occurred during the past century) in the depth range of 60 km to 220 km, resulting in significant seismic risk of the densely populated Bucharest area. The oceanic lithosphere slab beneath Vrancea area moved into an almost vertical position when convergence of plates come to a halt and suction force of the subducting plate vanished. In addition, since subduction occurred in an arcuate geometry, the slab is likely to be segmented as suggested by hypocenter distribution. Wortel and Spakman pioneered the idea of slab detachment, based on tomographic images of the upper mantle beneath the Mediterranean. The detachment hypothesis appears to be compatible with the magmatic evolution and the metamorphic patterns in Vrancea collisional orogenic region. Uniform high-precision hypocentre locations of the whole data set are very important in a seismically active area like Vrancea, where the seismic database is a prerequisite for tectonic interpretation and seismic hazard assessment. Well-constrained earthquake data are also extremely useful for studies focused on high-resolution imaging of the complex continental subduction process in Vrancea. To obtain a better image of the structure beneath Vrancea zone it is necessary to have a good velocity model, a well constrained topography model and detailed geological information. To compute a good velocity model we need a data base containing a large number of local, regional and teleseismic well-located events. The recent international tomographic experiment CALIXTO (Carpathian Arc Lithosphere X-Tomography) carried out in 1999, was designed to determine a 3D snapshot of the geodynamic evolution of the Carpathian arc beneath SE-Romania, and in particular, the ongoing slab break-off in the upper mantle beneath Vrancea region. A network consisting of

  5. Strain Anomalies during an Earthquake Sequence in the South Iceland Seismic Zone

    Science.gov (United States)

    Arnadottir, T.; Haines, A. J.; Geirsson, H.; Hreinsdottir, S.

    2017-12-01

    The South Iceland Seismic Zone (SISZ) accommodates E-W translation due to oblique spreading between the North American/Hreppar microplate and Eurasian plate, in South Iceland. Strain is released in the SISZ during earthquake sequences that last days to years, at average intervals of 80-100 years. The SISZ is currently in the midst of an earthquake sequence that started with two M6.5 earthquakes in June 2000, and continued with two M6 earthquakes in May 2008. Estimates of geometric strain accumulation, and seismic strain release in these events indicate that they released at most only half of the strain accumulated since the last earthquake cycle in 1896-1912. Annual GPS campaigns and continuous measurements during 2001-2015 were used to calculate station velocities and strain rates from a new method using the vertical derivatives of horizontal stress (VDoHS). This new method allows higher resolution of strain rates than other (older) approaches, as the strain rates are estimated by integrating VDoHS rates obtained by inversion rather than differentiating interpolated GPS velocities. Estimating the strain rates for eight 1-2 year intervals indicates temporal and spatial variation of strain rates in the SISZ. In addition to earthquake faulting, the strain rates in the SISZ are influenced by anthropogenic signals due to geothermal exploitation, and magma movements in neighboring volcanoes - Hekla and Eyjafjallajökull. Subtle signals of post-seismic strain rate changes are seen following the June 2000 M6.5 main shocks, but interestingly, much larger strain rate variations are observed after the two May 2008 M6 main shocks. A prominent strain anomaly is evident in the epicentral area prior to the May 2008 earthquake sequence. The strain signal persists over at least 4 years in the epicentral area, leading up to the M6 main shocks. The strain is primarily extension in ESE-WNW direction (sub-parallel to the direction of plate spreading), but overall shear across the N

  6. Dependence of Subduction Zone seismicity on Strain-Rate-Dependent Critical Homologous Temperature

    Science.gov (United States)

    Davis, P. M.

    2016-12-01

    Earthquakes mainly occur in crust or mantle that is below a critical temperature for the tectonic strain-rate, such that stress builds up to the breaking point before it can relax due to creep. Then long-range stress correlation gives rise to power law seismicity with large events. The limiting temperature depends on pressure, which is taken into account by finding a critical homologous temperature THc=T/TM above which earthquakes are rarely observed. We find that THc for ocean plates is ˜0.55. For California earthquakes, it is also close to 0.55. The uppermost mantle layer of oceanic plates of thickness ˜50 km is composed of harzburgite and depleted peridotite from which basalt has been removed to form ocean crust. Thus it has a higher melting temperature than the peridotite of the surrounding mantle, or the lower halves of plates. Thicknesses of seismicity in deep subduction zones, determined from 2D polynomial fits to a relocated catalog, are ˜50 km, which suggests that the earthquake channel is confined to this layer. We construct models to find homologous temperatures in slabs, and find that seismicity thicknesses are also, on average, confined to TH ≤ 0.55 ± 0.05. The associated rheology is compared with that obtained from flexure models of ocean lithosphere. The brittle-ductile transition occurs where viscosity drops from high values in the cold cores of slabs to values of 1022 to $1023 Pa s, i.e., where creep strain-rates become comparable to tectonic rates. The cutoff for deep earthquakes is not sharp. However they appear unlikely to occur if homologous temperature is high TH>0.55. Exceptions to the rule are anomalously deep earthquakes such as those beneath the Iceland and the Hawaiian hotspots, and the Newport Inglewood Fault. These are smaller events with short-range stress correlation, and can be explained if strain-rates are 2 to 3 orders of magnitude higher than those associated with earthquakes located where TH ≤0.55. We conclude that the

  7. Seismic Moment and Recurrence using Luminescence Dating Techniques: Characterizing brittle fault zone materials suitable for luminescence dating

    Science.gov (United States)

    Tsakalos, E.; Lin, A.; Bassiakos, Y.; Kazantzaki, M.; Filippaki, E.

    2017-12-01

    During a seismic-geodynamic process, frictional heating and pressure are generated on sediments fragments resulting in deformation and alteration of minerals contained in them. The luminescence signal enclosed in minerals crystal lattice can be affected and even zeroed during such an event. This has been breakthrough in geochronological studies as it could be utilized as a chronometer for the previous seismic activity of a tectonically active area. Although the employment of luminescence dating has in some cases been successfully described, a comprehensive study outlining and defining protocols for routine luminescence dating applied to neotectonic studies has not been forthcoming. This study is the experimental investigation, recording and parameterization of the effects of tectonic phenomena on minerals luminescence signal and the development of detailed protocols for the standardization of the luminescence methodology for directly dating deformed geological formations, so that the long-term temporal behaviour of seismically active faults could be reasonably understood and modeled. This will be achieved by: a) identifying and proposing brittle fault zone materials suitable for luminescence dating using petrological, mineralogical and chemical analyses and b) investigating the "zeroing" potential of the luminescence signal of minerals contained in fault zone materials by employing experimental simulations of tectonic processes in the laboratory, combined with luminescence measurements on samples collected from real fault zones. For this to be achieved, a number of samples collected from four faults of four different geographical regions will be used. This preliminary-first step of the study presents the microstructural, and mineralogical analyses for the characterization of brittle fault zone materials that contain suitable minerals for luminescence dating (e.g., quartz and feldspar). The results showed that the collected samples are seismically deformed fault

  8. Researching design solutions for frames of buildings in case of increased seismic intensity in specific zones

    OpenAIRE

    Panasyuk Leonid; Kravchenko Galina; Trufanova Elena

    2017-01-01

    Currently, there is a trend to increase the estimated seismic hazard for construction sites. With this, the buildings erected under the previously valid norms have the lesser hazard resistance. The present article inquiries into an issue of how the design solutions affect the safety of the building change under the increased seismic intensity. This article represents the calculation of a building without regard to seismic intensity and the same was made for a rate-7 seismic intensity district...

  9. Velocity and stress distributions of deep seismic zone under Izu-Bonin, Japan

    Science.gov (United States)

    Jiang, Guoming; Zhang, Guibin; Jia, Zhengyuan

    2017-04-01

    Deep earthquakes can provide the deep information of the Earth directly. We have collected the waveform data from 77 deep earthquakes with depth greater than 300 km under Izu-Bonin in Japan. To obtain the velocity structures of P- and S-wave, we have inversed the double-differences of travel times from deep event-pairs. These velocity anomalies can further yield the Poisson's ratio and the porosity. Our results show that the average P-wave velocity anomaly is lower 6%, however the S-wave anomaly is higher 2% than the iasp91 model. The corresponding Poisson's ratio and porosity anomaly are -24% and -4%, respectively, which suggest that the possibility of water in the deep seismic zone is very few and the porosity might be richer. To obtain the stress distribution, we have used the ISOLA method to analyse the non-double-couple components of moment tensors of 77 deep earthquakes. The focal mechanism results show that almost half of all earthquakes have larger double-couple (DC) components, but others have clear isotropic (ISO) or compensated linear vector dipole (CLVD) components. The non-double-couple components (ISO and CLVD) seem to represent the volume around a deep earthquake changes as it occurs, which could be explained the metastable olivine phase transition. All results indicate that the metastable olivine wedge (MOW) might exist in the Pacific slab under the Izu-Bonin region and the deep earthquakes might be induced by the phase change of metastable olivine.

  10. On the long-term seismic hazard analysis in the Zhangjiakou Penglai seismotectonic zone, China

    Science.gov (United States)

    Fu, Zhengxiang; Liu, Jie; Liu, Guiping

    2004-10-01

    The Zhangjiakou-Penglai seismotectonic zone (ZPSZ) lies in the northern part of North China and extends along the Zhangjiakou-Beijing-Tianjin-Bohai Bay-Penglai-Yellow Sea. It is about 900 km long and some 250 km wide in a northwest direction. The great Sanhe-Pinggu ( MS=8.0) earthquake occurred on September 1679 and the Tangshan ( MS=7.8) earthquake on July 1976 caused serious economic and life losses. According to some differences in crust structure and regional tectonic stress field, the ZPSZ is divided into western and eastern segment by the 117°E line for study on long-term seismic hazard analysis. An analysis of Gutenberg-Richter's empirical relation of earthquake-frequency and time process of historic and recent earthquakes along the eastern and western segments shows that the earthquake activity obeys a Poisson process, and these calculations indicate that the earthquake occurrence probability of MS=6.0-6.9 is 0.77-0.83 in the eastern segment and the earthquake occurrence probability of MS=7.0-7.9 is 0.78-0.80 in the western segment of the ZPSZ during a period from 2005 to 2015.

  11. Postseismic deformation following the June 2000 earthquake sequence in the south Iceland seismic zone

    Science.gov (United States)

    Arnadottir, T.; Jonsson, Sigurjon; Pollitz, F.F.; Jiang, W.; Feigl, K.L.

    2005-01-01

    We observe postseismic deformation on two spatiotemporal scales following Mw = 6.5 earthquakes in the south Iceland seismic zone on 17 and 21 June 2000. We see a rapidly decaying deformation transient lasting no more than 2 months and extending about 5 km away from the two main shock ruptures. This local, month-scale transient is captured by several radar interferograms and is also observed at a few campaign GPS sites located near the faults. A slower transient with a characteristic timescale of about a year is detected only by GPS measurements. The month-scale deformation pattern has been explained by poroelastic rebound due to postearthquake pore pressure changes. In contrast, the year-scale deformation can be explained by either afterslip at 8-14 km depth or viscoelastic relaxation of the lower crust and upper mantle in response to the coseismic stress changes. The optimal viscoelastic models have lower crustal viscosities of 0.5-1 ?? 1019 Pa s and upper mantle viscosity of ???3 ?? 1018 Pa s. Because of the limitations of our GPS campaign data, we consider both afterslip and viscoelastic relaxation as plausible mechanisms explaining the deformation field. Both types of postseismic deformation models suggest that the areas of large coseismic stress increase east of the 17 June and west of the 21 June ruptures continue to be loaded by the postseismic deformation. Copyright 2005 by the American Geophysical Union.

  12. Spatially dependent seismic anisotropy in the Tonga subduction zone: A possible contributor to the complexity of deep earthquakes

    Czech Academy of Sciences Publication Activity Database

    Vavryčuk, Václav

    2006-01-01

    Roč. 155, 1/2 (2006), s. 63-72 ISSN 0031-9201 R&D Projects: GA AV ČR IAA3012309; GA ČR GA205/02/0383 Institutional research plan: CEZ:AV0Z30120515 Keywords : deep-focus earthquakes * seismic anisotropy * subduction zones Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.440, year: 2006

  13. Structure and Deformation in the Transpressive Zone of Southern California Inferred from Seismicity, Velocity, and Qp Models

    Science.gov (United States)

    Hauksson, E.; Shearer, P.

    2004-12-01

    We synthesize relocated regional seismicity and 3D velocity and Qp models to infer structure and deformation in the transpressive zone of southern California. These models provide a comprehensive synthesis of the tectonic fabric of the upper to middle crust, and the brittle ductile transition zone that in some cases extends into the lower crust. The regional seismicity patterns in southern California are brought into focus when the hypocenters are relocated using the double difference method. In detail, often the spatial correlation between background seismicity and late Quaternary faults is improved as the hypocenters become more clustered, and the spatial patterns are more sharply defined. Along some of the strike-slip faults the seismicity clusters decrease in width and form alignments implying that in many cases the clusters are associated with a single fault. In contrast, the Los Angeles Basin seismicity remains mostly scattered, reflecting a 3D distribution of the tectonic compression. We present the results of relocating 327,000 southern California earthquakes that occurred between 1984 and 2002. In particular, the depth distribution is improved and less affected by layer boundaries in velocity models or other similar artifacts, and thus improves the definition of the brittle ductile transition zone. The 3D VP and VP/VS models confirm existing tectonic interpretations and provide new insights into the configuration of the geological structures in southern California. The models extend from the US-Mexico border in the south to the Coast Ranges and Sierra Nevada in the north, and have 15 km horizontal grid spacing and an average vertical grid spacing of 4 km, down to 22 km depth. The heterogeneity of the crustal structure as imaged in both the VP and VP/VS models is larger within the Pacific than the North America plate, reflecting regional asymmetric variations in the crustal composition and past tectonic processes. Similarly, the relocated seismicity is

  14. Mapping Deep Low Velocity Zones in Alaskan Arctic Coastal Permafrost using Seismic Surface Waves

    Science.gov (United States)

    Dou, S.; Ajo Franklin, J. B.; Dreger, D. S.

    2012-12-01

    Permafrost degradation may be an important amplifier of climate change; Thawing of near-surface sediments holds the potential of increasing greenhouse gas emissions due to microbial decomposition of preserved organic carbon. Recently, the characterization of "deep" carbon pools (several meters below the surface) in circumpolar frozen ground has increased the estimated amount of soil carbon to three times higher than what was previously thought. It is therefore potentially important to include the characteristics and processes of deeper permafrost strata (on the orders of a few to tens of meters below surface) in climate models for improving future predictions of accessible carbon and climate feedbacks. This extension is particularly relevant if deeper formations are not completely frozen and may harbor on-going microbial activity despite sub-zero temperatures. Unfortunately, the characterization of deep permafrost systems is non-trivial; logistics and drilling constraints often limit direct characterization to relatively shallow units. Geophysical measurements, either surface or airborne, are often the most effective tools for evaluating these regions. Of the available geophysical techniques, the analysis of seismic surface waves (e.g. MASW) has several unique advantages, mainly the ability to provide field-scale information with good depth resolution as well as penetration (10s to 100s of m with small portable sources). Surface wave methods are also able to resolve low velocity regions, a class of features that is difficult to characterize using traditional P-wave refraction methods. As part of the Department of Energy (DOE) Next-Generation Ecosystem Experiments (NGEE-Arctic) project, we conducted a three-day seismic field survey (May 12 - 14, 2012) at the Barrow Environmental Observatory, which is located within the Alaskan Arctic Coastal Plain. Even though permafrost at the study site is continuous, ice-rich and thick (>= 350m), our Multichannel Analysis of

  15. Local fluid flow and borehole strain in the South Iceland Seismic Zone

    Science.gov (United States)

    Jónsson, S.; Segall, P.; Ágústsson, K.; Agnew, D.

    2003-12-01

    Installation of 175 borehole strainmeters is planned for PBO. It is therefore vital to understand the behavior of existing strainmeter installations. We investigate signals recorded by three borehole dilatometers in the south Iceland seismic zone following two Mw6.5 earthquakes in June 2000. Poroelastic relaxation has been documented following these events based on InSAR and water level data [Jónsson et al., 2003, Nature]. According to poroelastic theory for a homogeneous isotropic (unfractured) medium, the anticipated post-seismic volumetric strain has the same sign as the coseismic strain step. For example, coseismic compression results in pore-pressure increases; post-earthquake fluid drainage causes additional compression. However, we find that observed strain changes vary considerably between different instruments after the earthquakes. One instrument (HEL) behaves as expected with transient strain increasing with the same sign as the coseismic strain step. Another instrument (SAU) shows partial strain relaxation, opposite in sign to the coseismic signal. The third (BUR) exhibits complete strain relaxation by 3-4 days after the earthquakes (i.e., BUR does not record any permanent strain). BUR has responded in the same fashion to three different earthquakes and two volcanic eruptions, demonstrating conclusively that the transient response is due to processes local to the borehole. Fluid drainage from cracks can explain these observations. Rapid straining results in compression (extension) of the rock and strainmeter. Fluid filled fractures near the borehole transmit normal stress, due to the relative incompressibility of water. Thus, at short time scales the instrument records a coseismic strain step. With time, however, fluid flows out of (in to) the fractures, and the normal stress transmitted across the fractures decreases (increases). As the stress relaxes the strainmeter expands (contracts), reversing the coseismic strain. Barometric responses are

  16. Structure of the Koyna-Warna Seismic Zone, Maharashtra, India: A possible model for large induced earthquakes elsewhere

    Science.gov (United States)

    Catchings, Rufus D.; Dixit, M.M.; Goldman, Mark R.; Kumar, S.

    2015-01-01

    The Koyna-Warna area of India is one of the best worldwide examples of reservoir-induced seismicity, with the distinction of having generated the largest known induced earthquake (M6.3 on 10 December 1967) and persistent moderate-magnitude (>M5) events for nearly 50 years. Yet, the fault structure and tectonic setting that has accommodated the induced seismicity is poorly known, in part because the seismic events occur beneath a thick sequence of basalt layers. On the basis of the alignment of earthquake epicenters over an ~50 year period, lateral variations in focal mechanisms, upper-crustal tomographic velocity images, geophysical data (aeromagnetic, gravity, and magnetotelluric), geomorphic data, and correlation with similar structures elsewhere, we suggest that the Koyna-Warna area lies within a right step between northwest trending, right-lateral faults. The sub-basalt basement may form a local structural depression (pull-apart basin) caused by extension within the step-over zone between the right-lateral faults. Our postulated model accounts for the observed pattern of normal faulting in a region that is dominated by north-south directed compression. The right-lateral faults extend well beyond the immediate Koyna-Warna area, possibly suggesting a more extensive zone of seismic hazards for the central India area. Induced seismic events have been observed many places worldwide, but relatively large-magnitude induced events are less common because critically stressed, preexisting structures are a necessary component. We suggest that releasing bends and fault step-overs like those we postulate for the Koyna-Warna area may serve as an ideal tectonic environment for generating moderate- to large- magnitude induced (reservoir, injection, etc.) earthquakes.

  17. Linkages of fracture network geometry and hydro-mechanical properties to spatio-temporal variations of seismicity in Koyna-Warna Seismic Zone

    Science.gov (United States)

    Selles, A.; Mikhailov, V. O.; Arora, K.; Ponomarev, A.; Gopinadh, D.; Smirnov, V.; Srinu, Y.; Satyavani, N.; Chadha, R. K.; Davulluri, S.; Rao, N. P.

    2017-12-01

    Well logging data and core samples from the deep boreholes in the Koyna-Warna Seismic Zone (KWSZ) provided a glimpse of the 3-D fracture network responsible for triggered earthquakes in the region. The space-time pattern of earthquakes during the last five decades show strong linkage of favourably oriented fractures system deciphered from airborne LiDAR and borehole structural logging to the seismicity. We used SAR interferometry data on surface displacements to estimate activity of the inferred faults. The failure in rocks at depths is largely governed by overlying lithostatic and pore fluid pressure in the rock matrix which are subject to change in space and time. While lithostatic pressure tends to increase with depth pore pressure is prone to fluctuations due to any change in the hydrological regime. Based on the earthquake catalogue data, the seasonal variations in seismic activity associated with annual fluctuations in the reservoir water level were analyzed over the time span of the entire history of seismological observations in this region. The regularities in the time changes in the structure of seasonal variations are revealed. An increase in pore fluid pressure can result in rock fracture and oscillating pore fluid pressures due to a reservoir loading and unloading cycles can cause iterative and cumulative damage, ultimately resulting in brittle failure under relatively low effective mean stress conditions. These regularities were verified by laboratory physical modeling. Based on our observations of main trends of spatio-temporal variations in seismicity as well as the spatial distribution of fracture network a conceptual model is presented to explain the triggered earthquakes in the KWSZ. The work was supported under the joint Russian-Indian project of the Russian Science Foundation (RSF) and the Department of Science and Technology (DST) of India (RSF project no. 16-47-02003 and DST project INT/RUS/RSF/P-13).

  18. Uppermost oceanic crust structure and properties from multichannel seismic data at the Alaska subduction zone

    Science.gov (United States)

    Becel, A.; Carton, H. D.; Shillington, D. J.

    2017-12-01

    The most heterogeneous, porous and permeable layer within a subducting oceanic crust is the uppermost layer called Layer 2A. This layer, made of extrusive basalts, forms at the ridge axis and persists as a thin ( 600 m) low-velocity cap in old crust. Nearing the trench axis, when oceanic plate bends, normal faults can be formed or reactivated at the outer-rise allowing a more vigorous hydrothermal circulation to resume within this layer. Porosity and heterogeneity within this layer are important to assess because these parameters might have a profound impact on subduction zone processes. However, conventional refraction data quality is rarely good enough to look into detail into the properties of the uppermost oceanic layer. Here we use 2D marine long-offset multi-channel seismic (MCS) reflection data collected offshore of the Alaska Peninsula during the ALEUT Program. The dataset was acquired aboard the R/V Marcus Langseth with a 636-channels, 8-km long streamer. We present initial results from three 140 km long profiles across the 52-56Myr old incoming Pacific oceanic crust formed at fast spreading rate: two perpendicular margin and one parallel margin profiles. Those profiles are located outboard of the Shumagin gaps. Outboard of this subduction zone segment, abundant bending related normal faults are imaged and concentrated within 50-60 km of the trench. Long-offset MCS data exhibit a prominent triplication that includes postcritical reflections and turning waves within the upper crust at offsets larger than 3 km. The triplication suggests the presence of a velocity discontinuity within the upper oceanic crust. We follow a systematic and uniform approach to extract upper crustal post-critical reflections and add them to them to the vertical incidence MCS images. Images reveal small-scale variations in the thickness of the Layer 2A and the strength of its base along the profiles. The second step consists of the downward continuation followed by travel

  19. THE STRUCTURE OF THE LITHOSPHERIC MANTLE OF THE SIBERAIN CRATON AND SEISMODYNAMICS OF DEFORMATION WAVES IN THE BAIKAL SEISMIC ZONE

    Directory of Open Access Journals (Sweden)

    A. A. Stepashko

    2013-01-01

    Full Text Available  The evolution and specific features of seismogynamics of the Baikal zones are reviewed in the context of interactions between deep deformation waves and the regional structure of the lithospheric mantle. The study is based on a model of the mantle structure with reference to chemical compositions of mantle peridotites from ophiolotic series located in the south-western framing of the Siberian craton (Fig. 1. The chemical zonation of the lithospheric mantle at the regional scale is determined from results of analyses of the heterogeneity of compositions of peridotites (Fig. 2, Table 1 and variations of contents of whole rock major components, such as iron, magnesium and silica (Fig. 3. According to spatial variations of the compositions of peridotites, the mantle has the concentric zonal structure, and the content of SiO2 is regularly decreasing, while concentrations of FeO∑ and MgO are increasing towards the centre of such structure (Fig. 4. This structure belongs to the mantle of the Siberian craton, which deep edge extends beyond the surface contour of the craton and underlies the north-western segment of the Central Asian orogenic belt.Results of the studies of peridotites of the Baikal region are consistent with modern concepts [Snyder, 2002; O’Reilly, Griffin, 2006; Chen et al., 2009] that suggest that large mantle lenses underlie the Archaean cratons (Fig. 5. The lenses are distinguished by high-density ultrabasic rocks and compose high-velocity roots of cratons which have remained isolated from technic processes. Edges of the mantle lenses may extend a few hundred kilometers beyond the limits of the cratons and underlie orogenic belts that frame the cratons, and this takes place in the south-western segment of the Siberian craton.The revealed structure of the lithospheric mantle is consistent with independent results of seismic and magmatectonical studies of the region. The Angara geoblock is located above the central part of the

  20. Multicomponent seismic loss estimation on the North Anatolian Fault Zone (Turkey)

    Science.gov (United States)

    karimzadeh Naghshineh, S.; Askan, A.; Erberik, M. A.; Yakut, A.

    2015-12-01

    Seismic loss estimation is essential to incorporate seismic risk of structures into an efficient decision-making framework. Evaluation of seismic damage of structures requires a multidisciplinary approach including earthquake source characterization, seismological prediction of earthquake-induced ground motions, prediction of structural responses exposed to ground shaking, and finally estimation of induced damage to structures. As the study region, Erzincan, a city on the eastern part of Turkey is selected which is located in the conjunction of three active strike-slip faults as North Anatolian Fault, North East Anatolian Fault and Ovacik fault. Erzincan city center is in a pull-apart basin underlain by soft sediments that has experienced devastating earthquakes such as the 27 December 1939 (Ms=8.0) and the 13 March 1992 (Mw=6.6) events, resulting in extensive amount of physical as well as economical losses. These losses are attributed to not only the high seismicity of the area but also as a result of the seismic vulnerability of the constructed environment. This study focuses on the seismic damage estimation of Erzincan using both regional seismicity and local building information. For this purpose, first, ground motion records are selected from a set of scenario events simulated with the stochastic finite fault methodology using regional seismicity parameters. Then, existing building stock are classified into specified groups represented with equivalent single-degree-of-freedom systems. Through these models, the inelastic dynamic structural responses are investigated with non-linear time history analysis. To assess the potential seismic damage in the study area, fragility curves for the classified structural types are derived. Finally, the estimated damage is compared with the observed damage during the 1992 Erzincan earthquake. The results are observed to have a reasonable match indicating the efficiency of the ground motion simulations and building analyses.

  1. The deep structure of the Sichuan basin and adjacent orogenic zones revealed by the aggregated deep seismic profiling datum

    Science.gov (United States)

    Xiong, X.; Gao, R.; Li, Q.; Wang, H.

    2012-12-01

    The sedimentary basin and the orogenic belt are the basic two tectonic units of the continental lithosphere, and form the basin-mountain coupling system, The research of which is the key element to the oil and gas exploration, the global tectonic theory and models and the development of the geological theory. The Sichuan basin and adjacent orogenic belts is one of the most ideal sites to research the issues above, in particular by the recent deep seismic profiling datum. From the 1980s to now, there are 11 deep seismic sounding profiles and 6 deep seismic reflection profiles and massive seismic broadband observation stations deployed around and crossed the Sichuan basin, which provide us a big opportunity to research the deep structure and other forward issues in this region. Supported by the National Natural Science Foundation of China (Grant No. 41104056) and the Fundamental Research Funds of the Institute of Geological Sciences, CAGS (No. J1119), we sampled the Moho depth and low-velocity zone depth and the Pn velocity of these datum, then formed the contour map of the Moho depth and Pn velocity by the interpolation of the sampled datum. The result shows the Moho depth beneath Sichuan basin ranges from 40 to 44 km, the sharp Moho offset appears in the western margin of the Sichuan basin, and there is a subtle Moho depression in the central southern part of the Sichuan basin; the P wave velocity can be 6.0 km/s at ca. 10 km deep, and increases gradually deeper, the average P wave velocity in this region is ca. 6.3 km/s; the Pn velocity is ca. 8.0-8.02 km/s in Sichuan basin, and 7.70-7.76 km/s in Chuan-Dian region; the low velocity zone appears in the western margin of the Sichuan basin, which maybe cause the cause of the earthquake.

  2. The ANSS response to the Mw 5.8 Central Virginia Seismic Zone earthquake of August 23, 2011

    Science.gov (United States)

    McNamara, D. E.; Horton, S.; Benz, H.; Earle, P. S.; Withers, M. M.; Hayes, G. P.; Kim, W. Y.; Chapman, M. C.; Herrmann, R. B.; Petersen, M. D.; Williams, R. A.

    2011-12-01

    An Mw 5.8 earthquake (depth=6km) occurred on August 23, 2011 (17:51:04 UTC) near Mineral, Virginia, which was widely felt from Maine to Georgia along the eastern seaboard and west to Chicago and western Tennessee. The USGS tallied nearly 142,000 felt reports submitted to the Did You Feel It (DYFI) internet community intensity system, making it the most widely felt earthquake since the web-site began, and demonstrating that more people felt this earthquake than any other in U.S. history. Significant damage was reported in the epicentral area and as far away as Washington D.C. (135 km away); minor damage was reported in Baltimore (200 km). The reverse faulting earthquake occurred on a northeast-striking plane within a region of diffuse seismicity known as the Central Virginia Seismic Zone. Within the first week, the mainshock was followed by 17 aftershocks with magnitude greater than 2, including Mw 4.5, 4.2, and 3.8 events. In the days following the mainshock, 46 portable seismic stations were deployed by several organizations, making this among the best-recorded aftershock sequence in the eastern U.S. Within 24 hours of the mainshock, 8 portable stations were deployed in time to record the largest aftershock to date (M4.5). We will present the results of our post-earthquake response, including attenuation and site amplification observations using portable aftershock station data, details on the initial USGS NEIC post earthquake response products and an assessment of the seismotectonics of the Central Virginia Seismic Zone based on aftershock locations and source parameter modeling of the larger earthquakes.

  3. Theoretical models for crustal displacement assessment and monitoring in Vrancea-Focsani seismic zone by integrated remote sensing and local geophysical data for seismic prognosis

    International Nuclear Information System (INIS)

    Zoran, Maria; Ciobanu, Mircea; Mitrea, Marius Gabriel; Talianu, Camelia; Cotarlan, Costel; Mateciuc, Doru; Radulescu, Florin; Biter Mircea

    2002-01-01

    The majority of strong Romanian earthquakes has the origin in Vrancea region. Subduction of the Black Sea Sub-Plate under the Pannonian Plate produces faulting processes. Crustal displacement identification and monitoring is very important for a seismically active area like Vrancea-Focsani. Earthquake displacements are very well revealed by satellite remote sensing data. At the same time, geomorphologic analysis of topographic maps is carried out and particularly longitudinal and transverse profiles are constructed, as well as structural-geomorphologic maps. Faults are interpreted by specific features in nature of relief, straightness of line of river beds and their tributaries, exits of springs, etc. Remote sensing analysis and field studies of active faults can provide a geologic history that overcomes many of the shortcomings of instrumental and historic records. Our theoretical models developed in the frame of this project are presented as follows: a) Spectral Mixture Analysis model of geomorphological and topographic characteristics for Vrancea region proposed for satellite images analysis which assumes that the different classes present in a pixel (image unit) contribute independently to its reflectance. Therefore, the reflectance of a pixel at a particular frequency is the sum of the reflectances of the components at that frequency. The same test region in Vrancea area is imaged at several different frequencies (spectral bands), leading to multispectral observations for each pixel. It is useful to merge different satellite data into a hybrid image with high spatial and spectral resolution to create detailed images map of the abundance of various materials within the scene based on material spectral fingerprint. Image fusion produces a high-resolution multispectral image that is then unmixed into high-resolution material maps. b) Model of seismic cross section analysis which is applied in seismic active zones morphology. Since a seismic section can be

  4. Las noticias de Madrid (News from Madrid

    Directory of Open Access Journals (Sweden)

    Wahrle Suzanne

    2006-09-01

    Full Text Available Abstract Over 5,000 participants attended the 10th International Conference on Alzheimer's Disease (ICAD and Related Disorders in Madrid, Spain from July 15–20, 2006. Highlights of the conference included reports on brain imaging, the discovery of mutations in the progranulin gene that cause frontotemporal dementia, the finding that neuregulin-1 is a substrate for BACE1 and new interest in the connection between Alzheimer's disease and metabolic syndromes.

  5. Crustal structure at the western end of the North Anatolian Fault Zone from deep seismic sounding

    Directory of Open Access Journals (Sweden)

    B. Baier

    2001-06-01

    Full Text Available The first deep seismic sounding experiment in Northwestern Anatolia was carried out in October 1991 as part of the "German - Turkish Project on Earthquake Prediction Research" in the Mudurnu area of the North Anatolian Fault Zone. The experiment was a joint enterprise by the Institute of Meteorology and Geophysics of Frankfurt University, the Earthquake Research Institute (ERI in Ankara, and the Turkish Oil Company (TPAO. Two orthogonal profiles, each 120 km in length with a crossing point near Akyazi, were covered in succession by 30 short period tape recording seismograph stations with 2 km station spacing. 12 shots, with charge sizes between 100 and 250 kg, were fired and 342 seismograms out of 360 were used for evaluation. By coincidence an M b = 4.5 earthquake located below Imroz Island was also recorded and provided additional information on Moho and the sub-Moho velocity. A ray tracing method orginally developed by Weber (1986 was used for travel time inversion. From a compilation of all data two generalized crustal models were derived, one with velocity gradients within the layers and one with constant layer velocities. The latter consists of a sediment cover of about 2 km with V p » 3.6 km/s, an upper crystalline crust down to 13 km with V p » 5.9 km/s, a middle crust down to 25 km depth with V p » 6.5 km/s, a lower crust down to 39 km Moho depth with V p » 7.0 km/s and V p » 8.05 km/s below the Moho. The structure of the individual profiles differs slightly. The thickest sediment cover is reached in the Izmit-Sapanca-trough and in the Akyazi basin. Of particular interest is a step of about 4 km in the lower crust near Lake Sapanca and probably an even larger one in the Moho (derived from the Imroz earthquake data. After the catastrophic earthquake of Izmit on 17 August 1999 this significant heterogeneity in crustal structure appears in a new light with regard to the possible cause of the Izmit earthquake. Heterogeneities in

  6. Optimizing the design of vertical seismic profiling (VSP) for imaging fracture zones over hardrock basement geothermal environments

    Science.gov (United States)

    Reiser, Fabienne; Schmelzbach, Cedric; Maurer, Hansruedi; Greenhalgh, Stewart; Hellwig, Olaf

    2017-04-01

    A primary focus of geothermal seismic imaging is to map dipping faults and fracture zones that control rock permeability and fluid flow. Vertical seismic profiling (VSP) is therefore a most valuable means to image the immediate surroundings of an existing borehole to guide, for example, the placing of new boreholes to optimize production from known faults and fractures. We simulated 2D and 3D acoustic synthetic seismic data and processed it through to pre-stack depth migration to optimize VSP survey layouts for mapping moderately to steeply dipping fracture zones within possible basement geothermal reservoirs. Our VSP survey optimization procedure for sequentially selecting source locations to define the area where source points are best located for optimal imaging makes use of a cross-correlation statistic, by which a subset of migrated shot gathers is compared with a target or reference image from a comprehensive set of source gathers. In geothermal exploration at established sites, it is reasonable to assume that sufficient à priori information is available to construct such a target image. We generally obtained good results with a relatively small number of optimally chosen source positions distributed over an ideal source location area for different fracture zone scenarios (different dips, azimuths, and distances from the surveying borehole). Adding further sources outside the optimal source area did not necessarily improve the results, but rather resulted in image distortions. It was found that fracture zones located at borehole-receiver depths and laterally offset from the borehole by 300 m can be imaged reliably for a range of the different dips, but more source positions and large offsets between sources and the borehole are required for imaging steeply dipping interfaces. When such features cross-cut the borehole, they are particularly difficult to image. For fracture zones with different azimuths, 3D effects are observed. Far offset source positions

  7. Shallow seismic structure of Kunlun fault zone in northern Tibetan Plateau, China: Implications for the 2001 M s8.1 Kunlun earthquake

    Science.gov (United States)

    Wang, Chun-Yong; Mooney, W.D.; Ding, Z.; Yang, J.; Yao, Z.; Lou, H.

    2009-01-01

    The shallow seismic velocity structure of the Kunlun fault zone (KLFZ) was jointly deduced from seismic refraction profiling and the records of trapped waves that were excited by five explosions. The data were collected after the 2001 Kunlun M s8.1 earthquake in the northern Tibetan Plateau. Seismic phases for the in-line record sections (26 records up to a distance of 15 km) along the fault zone were analysed, and 1-D P- and S-wave velocity models of shallow crust within the fault zone were determined by using the seismic refraction method. Sixteen seismic stations were deployed along the off-line profile perpendicular to the fault zone. Fault-zone trapped waves appear clearly on the record sections, which were simulated with a 3-D finite difference algorithm. Quantitative analysis of the correlation coefficients of the synthetic and observed trapped waveforms indicates that the Kunlun fault-zone width is 300 m, and S-wave quality factor Q within the fault zone is 15. Significantly, S-wave velocities within the fault zone are reduced by 30-45 per cent from surrounding rocks to a depth of at least 1-2 km, while P-wave velocities are reduced by 7-20 per cent. A fault-zone with such P- and S-low velocities is an indication of high fluid pressure because Vs is affected more than Vp. The low-velocity and low-Q zone in the KLFZ model is the effect of multiple ruptures along the fault trace of the 2001 M s8.1 Kunlun earthquake. ?? 2009 The Authors Journal compilation ?? 2009 RAS.

  8. SEISMIC PICTURE OF A FAULT ZONE. WHAT CAN BE GAINED FROM THE ANALYSIS OF FINE PATTERNS OF SPATIAL DISTRIBUTION OF WEAK EARTHQUAKE CENTERS?

    Directory of Open Access Journals (Sweden)

    Gevorg G. Kocharyan

    2010-01-01

    Full Text Available Association of earthquake hypocenters with fault zones appears more pronounced in cases with more accurately determined positions of the earthquakes. For complex, branched structures of major fault zones, it is assumed that some of the earthquakes occur at feathering fractures of smaller scale.It is thus possible to develop a «seismological» criterion for definition of a zone of dynamic influence of faults, i.e. the zone containing the majority of earthquakes associated with the fault zone under consideration.In this publication, seismogenic structures of several fault zones located in the San-Andreas fault system are reviewed. Based on the data from a very dense network of digital seismic stations installed in this region and with application of modern data processing methods, differential coordinates of microearthquakes can be determined with errors of about first dozens of meters.It is thus possible to precisely detect boundaries of the areas wherein active deformation processes occur and to reveal spatial patterns of seismic event localization.In our analyses, data from the most comprehensive seismic catalog were used. The catalogue includes information on events which occurred and were registered in North California in the period between January 1984 and May 2003. In this publication, the seismic data processing results and regularities revealed during the analyses are compared with the data obtained from studies of fault structures, modeling and numerical simulation results. Results of quantitative research of regularities of localization of seismic sources inside fault zones are presented.It is demonstrated by 3D models that seismic events are localized in the vicinity of an almost plain surface with a nearly constant angle of dip, the majority of events being concentrated at that conventional surface.Detection of typical scopes of seismicity localization may prove critical for solution of problems of technogenic impact on fault zones

  9. New Constraints on Late Pleistocene - Holocene Slip Rates and Seismic Behavior Along the Panamint Valley Fault Zone, Eastern California

    Science.gov (United States)

    Hoffman, W.; Kirby, E.; McDonald, E.; Walker, J.; Gosse, J.

    2008-12-01

    Space-time patterns of seismic strain release along active fault systems can provide insight into the geodynamics of deforming lithosphere. Along the eastern California shear zone, fault systems south of the Garlock fault appear to have experienced an ongoing pulse of seismic activity over the past ca. 1 kyr (Rockwell et al., 2000). Recently, this cluster of seismicity has been implicated as both cause and consequence of the oft-cited discrepancy between geodetic velocities and geologic slip rates in this region (Dolan et al., 2007; Oskin et al., 2008). Whether other faults within the shear zone exhibit similar behavior remains uncertain. Here we report the preliminary results of new investigations of slip rates and seismic history along the Panamint Valley fault zone (PVFZ). The PVFZ is characterized by dextral, oblique-normal displacement along a moderately to shallowly-dipping range front fault. Previous workers (Zhang et al., 1990) identified a relatively recent surface rupture confined to a ~25 km segment of the southern fault zone and associated with dextral displacements of ~3 m. Our mapping reveals that youthful scarps ranging from 2-4 m in height are distributed along the central portion of the fault zone for at least 50 km. North of Ballarat, a releasing jog in the fault zone forms a 2-3 km long embayment. Displacement of debris-flow levees and channels along NE-striking faults that confirm that displacement is nearly dip-slip, consistent with an overall transport direction toward ~340°, and affording an opportunity to constrain fault displacement directly from the vertical offset of alluvial surfaces of varying age. At the mouth of Happy Canyon, the frontal fault strand displaces a fresh debris-flow by ~3-4 m; soil development atop the debris-flow surface is incipient to negligible. Radiocarbon ages from logs embedded in the flow matrix constrain the timing of the most recent event to younger than ~ 600 cal yr BP. Older alluvial surfaces, such as that

  10. Discrimination and Assessment of Induced Seismicity in Active Tectonic Zones: A Case Study from Southern California

    Science.gov (United States)

    Bachmann, C. E.; Lindsey, N.; Foxall, W.; Robertson, M.

    2014-12-01

    Earthquakes induced by human activity have become a matter of heightened public concern during recent years. Of particular concern is seismicity associated with wastewater injection, which has included events having magnitudes greater than 5. The causes of the induced events are primarily changes in pore-pressure, fluid volume and perhaps temperature due to injection. Recent research in the US has focused on mid-continental regions having low rates of naturally-occurring seismicity, where induced events can be identified by relatively straightforward spatial and temporal correlation of seismicity with high-volume injection activities. Recent examples include events correlated with injection of wastewater in Oklahoma, Arkansas, Texas and Ohio, and long-term brine injection in the Paradox Valley in Colorado. Even in some of the cases where there appears at first sight to be a clear spatial correlation between seismicity and injection, it has been difficult to establish causality definitively. Here, we discuss methods to identify induced seismicity in active tectonic regions. We concentrate our study on Southern California, where large numbers of wastewater injection wells are located in oil-producing basins that experience moderate to high rates of naturally-occurring seismicity. Using the catalog of high-precision CISN relocations produced by Hauksson et al. (BSSA, 2012), we aim to discriminate induced from natural events based on spatio-temporal patterns of seismicity occurrence characteristics and their relationships to injection activities, known active faults and other faults favorably oriented for slip under the tectonic stress field. Since the vast majority of induced earthquakes are very small, it is crucial to include all events above the detection threshold of the CISN in each area studied. In addition to exploring the correlation of seismicity to injection activities in time and space, we analyze variations in frequency-magnitude distributions, which can

  11. 2D Seismic Velocity Modelling in the Southeastern Romanian Carpathians and its Foreland (Vrancea Zone and Focsani Basin)

    Science.gov (United States)

    Stephenson, R.; Bocin, A.; Tryggvason, A.

    2003-12-01

    The DACIA-PLAN (Danube and Carpathian Integrated Action on Processes in the Lithosphere and Neotectonics) deep seismic reflection survey was performed in August-September 2001, with the objective of obtaining of new information on the deep structure of the external Carpathians nappes and the architecture of Tertiary/Quaternary basins developed within and adjacent to the seismically-active Vrancea Zone, including the rapidly subsiding Focsani Basin. The DACIA-PLAN profile is about 140 km long, having a roughly NW-SE direction, from near the southeast Transylvanian Basin, across the mountainous southeastern Carpathians and their foreland to near the Danube Dalta. A high resolution 2D velocity model of the upper crust along the seismic profile has been determined from a first-arrival tomographic inversion of the DACIA-PLAN data. The shallowing of Palaeozoic-Mesozoic basement, and related structural heterogeneity within it, beneath the eastern flank of the Focsani Basin is clearly seen. Velocity heterogeneity within the Carpathian nappe belt is also evident and is indicative of internal structural complexity, including the presence of salt bodies and basement involvement in thrusting, thus favouring some current geological models over others. The presence of basement involvement implies the compressional reactivation of pre-existing basement normal faults. Members of the DACIA-PLAN/TomoSeis Working Group (see poster) should be considered as co-authors of this presentation.

  12. Migration of the deforming zone during seismic shear and implications for field observations, dynamic weakening, and the onset of melting

    Science.gov (United States)

    Platt, J. D.; Rice, J. R.

    2013-12-01

    Prior work in our group has shown how micron-scale strain rate localization can be explained using models for thermal pressurization and thermal decomposition in fluid-saturated gouge materials. Using parameters modeling a typical centroidal depth for a crustal seismogenic zone we predicted localized zone thicknesses in line with laboratory (Brantut et al., 2008; Kitajima et al., 2010) and field (Chester and Chester, 1998; Heermance et al., 2003; De Paola et al., 2008) observations. Further work has shown that the localized zone need not remain in a single location and may migrate across the gouge layer, in agreement with laboratory observations that show a thickening of the highly localized material with slip, and a distinct banded structure within the highly localized material (T. Mitchell, priv. comm.; Kitajima et al., 2010). We have identified two mechanisms that could cause migration. The first is a combination of thermal diffusion, hydraulic diffusion and thermal pressurization, which leads to the location of maximum pore pressure moving away from its initial position [Rice, 2006]. Since the maximum strain rate coincides with the maximum pore pressure, this causes the deforming zone to move across the gouge layer. The second mechanism is reactant depletion in a material undergoing thermal decomposition. Fluid pressurization and strain rate are slaved to the reaction, so as the reactant depletes the deforming zone will migrate towards fresh reactant. An additional symmetry breaking instability exists but is not discussed here. We have also explored how spatial variations in fault gouge properties may control the distribution of seismic shear. Since at seismic slip rates localization in a fluid-saturated material is controlled largely by pore pressure generation and hydraulic diffusion, regions that generate or trap pore pressures more efficiently will attract straining. Numerical simulations show that the deforming zone moves towards regions of low hydraulic

  13. Geothermal and seismic evidence for a southeastern continuation of the three pagodas fault zone into the Gulf of Thailand

    Directory of Open Access Journals (Sweden)

    Prinya Putthapiban

    2012-09-01

    Full Text Available Aerial photographic maps and landsat image interpretations suggest the major fault segments of the Three PagodaFault (TPF Zone and Sri Swat Fault (SSF Zone are oriented parallel or sub-parallel in the same NW-SE directions. The KwaeNoi River is running along the TPF in the south whereas the Kwae Yai River is running along the SSF in the north. Thesoutheastern continuation of both faults is obscured by thick Cenozoic sediments. Hence, surface lineaments cannot betraced with confidence. However, based on some interpretations of the airborne magnetic survey data, the trace of such faultsare designated to run through the western part of Bangkok and the northern end of the Gulf of Thailand. Paleo-earthquakesand the presence of hot springs along the fault zones indicate that they are tectonically active. The changes of both physicaland chemical properties of the water from Hin Dart Hot Spring and those of the surface water from a shallow well at Ban KhaoLao during the Great Sumatra–Andaman Earthquake on 26th of December 2004 clearly indicated that the southeastern continuation of the TPF is at least as far south as Pak Tho District, Ratburi. Our new evidence of the alignment of the high heatflow in the upper part of the Gulf of Thailand verified that the TPF also extend into the Gulf via Samut Songkhram Province.Studies of the seismic data from two survey lines along the Western part of the upper Gulf of Thailand acquired by BritoilPlc. in 1986, namely Line A which is approximately 60 km long, starting from Bang Khen passing through Bang Khae andending in Samut Songkhram and Line B is approximately 30 km long starting from Samut Sakon ending in Samut Song Khramsuggest that all the faults or fractures along these seismic profiles are covered by sediments of approximately 230 m thickwhich explain that the fault underneath these seismic lines is quite old and may not be active. The absent of sign or trace ofthe TPF Path to the west suggested that there

  14. High resolution imaging of vadose zone transport using crosswell radar and seismic methods; TOPICAL

    International Nuclear Information System (INIS)

    Majer, Ernest L.; Williams, Kenneth H.; Peterson, John E.; Daley, Thomas E.

    2001-01-01

    The summary and conclusions are that overall the radar and seismic results were excellent. At the time of design of the experiments we did not know how well these two methods could penetrate or resolve the moisture content and structure. It appears that the radar could easily go up to 5, even 10 meters between boreholes at 200 Mhz and even father (up to 20 to 40 m) at 50 Mhz. The seismic results indicate that at several hundred hertz propagation of 20 to 30 meters giving high resolution is possible. One of the most important results, however is that together the seismic and radar are complementary in their properties estimation. The radar being primarily sensitive to changes in moisture content, and the seismic being primarily sensitive to porosity. Taken in a time lapse sense the radar can show the moisture content changes to a high resolution, with the seismic showing high resolution lithology. The significant results for each method are: Radar: (1) Delineated geological layers 0.25 to 3.5 meters thick with 0.25 m resolution; (2) Delineated moisture movement and content with 0.25 m resolution; (3) Compared favorably with neutron probe measurements; and (4) Penetration up to 30 m. Radar results indicate that the transport of the riverwater is different from that of the heavier and more viscous sodium thiosulfate. It appears that the heavier fluids are not mixing readily with the in-situ fluids and the transport may be influenced by them. Seismic: (1) Delineated lithology at .25 m resolution; (2) Penetration over 20 meters, with a possibility of up to 30 or more meters; and (3) Maps porosity and density differences of the sediments. Overall the seismic is mapping the porosity and density distribution. The results are consistent with the flow field mapped by the radar, there is a change in flow properties at the 10 to 11 meter depth in the flow cell. There also appears to be break through by looking at the radar data with the denser sodium thiosulfate finally

  15. Active crustal deformation of the El Salvador Fault Zone (ESFZ) using GPS data: Implications in seismic hazard assessment

    Science.gov (United States)

    Staller, Alejandra; Benito, Belen; Jesús Martínez-Díaz, José; Hernández, Douglas; Hernández-Rey, Román; Alonso-Henar, Jorge

    2014-05-01

    El Salvador, Central America, is part of the Chortis block in the northwestern boundary of the Caribbean plate. This block is interacting with a diffuse triple junction point with the Cocos and North American plates. Among the structures that cut the Miocene to Pleistocene volcanic deposits stands out the El Salvador Fault Zone (ESFZ): It is oriented in N90º-100ºE direction, and it is composed of several structural segments that deform Quaternary deposits with right-lateral and oblique slip motions. The ESFZ is seismically active and capable of producing earthquakes such as the February 13, 2001 with Mw 6.6 (Martínez-Díaz et al., 2004), that seriously affected the population, leaving many casualties. This structure plays an important role in the tectonics of the Chortis block, since its motion is directly related to the drift of the Caribbean plate to the east and not with the partitioning of the deformation of the Cocos subduction (here not coupled) (Álvarez-Gómez et al., 2008). Together with the volcanic arc of El Salvador, this zone constitutes a weakness area that allows the motion of forearc block toward the NW. The geometry and the degree of activity of the ESFZ are not studied enough. However their knowledge is essential to understand the seismic hazard associated to this important seismogenic structure. For this reason, since 2007 a GPS dense network was established along the ESFZ (ZFESNet) in order to obtain GPS velocity measurements which are later used to explain the nature of strain accumulation on major faults along the ESFZ. The current work aims at understanding active crustal deformation of the ESFZ through kinematic model. The results provide significant information to be included in a new estimation of seismic hazard taking into account the major structures in ESFZ.

  16. Velocity structure and the role of fluids in the West Bohemia Seismic Zone

    Czech Academy of Sciences Publication Activity Database

    Alexandrakis, C.; Calò, M.; Bouchaala, F.; Vavryčuk, Václav

    2014-01-01

    Roč. 5, č. 2 (2014), s. 863-872 ISSN 1869-9510 R&D Projects: GA ČR(CZ) GAP210/12/1491 EU Projects: European Commission(XE) 230669 - AIM Institutional support: RVO:67985530 Keywords : seismic tomography * Bohemia/Vogtland seismoactive region * WEBNET Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.270, year: 2014

  17. Seismic monitoring at the geothermal zone of Acoculco, Pue., Mexico; Monitoreo sismico en la zona geotermica de Acoculco, Pue., Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Lermo, Javier; Antayhua, Yanet; Bernal, Isabel [Universidad Nacional Autonoma de Mexico (UNAM), Instituto de Ingenieria Mexico, D.F. (Mexico); Venegas, Saul; Arredondo, Jesus [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico)]. E-mail: jles@pumas.iingen.unam.mx

    2009-01-15

    Results are presented of a research project to study seismic activity in the Acoculco geothermal zone, Puebla, Mexico. Geological and geophysical information was collected for the zone and a seismic network composed of seven digital seismographs was installed over four months (August-November 2004). Of the 30 regional earthquakes located by the National Seismological Service, 14 were at the subduction zone, 7 in the intra-plate zone, 6 of cortical type were in the Mexican Volcanic Belt, and 3 had deep origins in the Veracruz and Chiapas regions. Although there were no local earthquakes, probably due to the short monitoring span or lack of currently active zones, velocity models were defined near the springs of Los Azufres and Alcaparrosa, with lineal arrangements of wide-band seismic stations (SPAC) and strata identified in the exploratory well EAC-1, drilled by the Comision Federal de Electricidad. By using the registers of regional earthquakes, the site-effects were estimated on the six temporary seismic stations, whose empirical transfer functions were used to validate a velocities model proposed for the endhoreic basin. The proposed velocity models, both for the endhoreic basin and outside it, enhance the previous interpretations. They confirm the geo-electrical model proposed for the zone is adequate and they provide dynamic conditions for the model, such as propagation velocities of the P and S waves and densities and attenuation. [Spanish] Se presentan los resultados de un proyecto de investigacion para estudiar la actividad sismica de la zona geotermica de Acoculco, Puebla, Mexico. Con este fin se recopilo informacion geologica y geofisica de la zona y se instalo durante cuatro meses (de agosto a noviembre de 2004) una red sismica conformada por siete sismografos digitales. Se registraron 30 sismos regionales que fueron localizados por el Servicio Sismologico Nacional en la zona de subduccion (14), en la zona de intraplaca (7), de tipo cortical del Eje

  18. Modeling the Geometry of Plate Boundary and Seismic Structure in the Southern Ryukyu Trench Subduction Zone, Japan, Using Amphibious Seismic Observations

    Science.gov (United States)

    Yamamoto, Y.; Takahashi, T.; Ishihara, Y.; Kaiho, Y.; Arai, R.; Obana, K.; Nakanishi, A.; Miura, S.; Kodaira, S.; Kaneda, Y.

    2018-02-01

    Here we present the new model, the geometry of the subducted Philippine Sea Plate interface beneath the southern Ryukyu Trench subduction zone, estimated from seismic tomography and focal mechanism estimation by using passive and active data from a temporary amphibious seismic network and permanent land stations. Using relocated low-angle thrust-type earthquakes, repeating earthquakes, and structural information, we constrained the geometry of plate boundary from the trench axis to a 60 km depth with uncertainties of less than 5 km. The estimated plate geometry model exhibited large variation, including a pronounced convex structure that may be evidence of a subducted seamount in the eastern portion of study area, whereas the western part appeared smooth. We also found that the active earthquake region near the plate boundary, defined by the distance from our plate geometry model, was clearly separated from the area dominated by short-term slow-slip events (SSEs). The oceanic crust just beneath the SSE-dominant region, the western part of the study area, showed high Vp/Vs ratios (>1.8), whereas the eastern side showed moderate or low Vp/Vs (<1.75). We interpreted this as an indication that high fluid pressures near the surface of the slab are contributing to the SSE activities. Within the toe of the mantle wedge, P and S wave velocities (<7.5 and <4.2 km/s, respectively) lower than those observed through normal mantle peridotite might suggest that some portions of the mantle may be at least 40% serpentinized.

  19. Bloque de viviendas. Madrid

    Directory of Open Access Journals (Sweden)

    Lamela, Antonio

    1960-04-01

    Full Text Available Se trata de la edificación de dos parcelas colindantes formando un conjunto de composición exenta en la Avenida del Generalísimo de Madrid, avenida que puede y que debía haber sido una de las mejores vías de la capital de España.

  20. Seismically active column and volcanic plumbing system beneath the island arc of the Izu-Bonin subduction zone

    Science.gov (United States)

    Špičák, Aleš; Vaněk, Jiří; Hanuš, Václav

    2009-12-01

    A detailed spatio-temporal analysis of teleseismic earthquake occurrence (mb > 4.0) along the convergent margin of the Izu-Bonin-Mariana arc system reveals an anomalously high concentration of events between 27° and 30.5°N, beneath a chain of seamounts between Tori-shima and Nishino-shima volcanoes. This seismicity is dominated by the 1985/1986 earthquake swarm represented in the Engdahl-van der Hilst-Buland database by 146 earthquakes in the body wave magnitude range 4.3-5.8 and focal depth range 1-100 km. The epicentral cluster of the swarm is elongated parallel to the volcanic chain. Available focal mechanisms are consistent with an extensional tectonic regime and reveal nodal planes with azimuths close to that of the epicentral cluster. Earthquakes of the 1985/1986 swarm occurred in seven time phases. Seismic activity migrated in space from one phase to the other. Earthquake foci belonging to individual phases of the swarm aligned in vertically disposed seismically active columns. The epicentral zones of the columns are located in the immediate vicinity of seamounts Suiyo and Mokuyo, recently reported by the Japanese Meteorological Agency as volcanically active. The three observations-episodic character of earthquake occurrence, column-like vertically arranged seismicity pattern, and existence of volcanic seamounts at the seafloor above the earthquake foci-led us to interpret the 1985/1986 swarm as a consequence of subduction-related magmatic and/or fluid activity. A modification of the shallow earthquake swarm magmatic model of D. Hill fits earthquake foci distribution, tectonic stress orientation and fault plane solutions. The 1985/1986 deep-rooted earthquake swarm in the Izu-Bonin region represents an uncommon phenomenon of plate tectonics. The portion of the lithospheric wedge that was affected by the swarm should be composed of fractured rigid, brittle material so that the source of magma and/or fluids which might induce the swarm should be situated at a

  1. Estimation of recurrence interval of large earthquakes on the central Longmen Shan fault zone based on seismic moment accumulation/release model.

    Science.gov (United States)

    Ren, Junjie; Zhang, Shimin

    2013-01-01

    Recurrence interval of large earthquake on an active fault zone is an important parameter in assessing seismic hazard. The 2008 Wenchuan earthquake (Mw 7.9) occurred on the central Longmen Shan fault zone and ruptured the Yingxiu-Beichuan fault (YBF) and the Guanxian-Jiangyou fault (GJF). However, there is a considerable discrepancy among recurrence intervals of large earthquake in preseismic and postseismic estimates based on slip rate and paleoseismologic results. Post-seismic trenches showed that the central Longmen Shan fault zone probably undertakes an event similar to the 2008 quake, suggesting a characteristic earthquake model. In this paper, we use the published seismogenic model of the 2008 earthquake based on Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) data and construct a characteristic seismic moment accumulation/release model to estimate recurrence interval of large earthquakes on the central Longmen Shan fault zone. Our results show that the seismogenic zone accommodates a moment rate of (2.7 ± 0.3) × 10¹⁷ N m/yr, and a recurrence interval of 3900 ± 400 yrs is necessary for accumulation of strain energy equivalent to the 2008 earthquake. This study provides a preferred interval estimation of large earthquakes for seismic hazard analysis in the Longmen Shan region.

  2. Estimation of Recurrence Interval of Large Earthquakes on the Central Longmen Shan Fault Zone Based on Seismic Moment Accumulation/Release Model

    Directory of Open Access Journals (Sweden)

    Junjie Ren

    2013-01-01

    Full Text Available Recurrence interval of large earthquake on an active fault zone is an important parameter in assessing seismic hazard. The 2008 Wenchuan earthquake (Mw 7.9 occurred on the central Longmen Shan fault zone and ruptured the Yingxiu-Beichuan fault (YBF and the Guanxian-Jiangyou fault (GJF. However, there is a considerable discrepancy among recurrence intervals of large earthquake in preseismic and postseismic estimates based on slip rate and paleoseismologic results. Post-seismic trenches showed that the central Longmen Shan fault zone probably undertakes an event similar to the 2008 quake, suggesting a characteristic earthquake model. In this paper, we use the published seismogenic model of the 2008 earthquake based on Global Positioning System (GPS and Interferometric Synthetic Aperture Radar (InSAR data and construct a characteristic seismic moment accumulation/release model to estimate recurrence interval of large earthquakes on the central Longmen Shan fault zone. Our results show that the seismogenic zone accommodates a moment rate of (2.7 ± 0.3 × 1017 N m/yr, and a recurrence interval of 3900 ± 400 yrs is necessary for accumulation of strain energy equivalent to the 2008 earthquake. This study provides a preferred interval estimation of large earthquakes for seismic hazard analysis in the Longmen Shan region.

  3. A Bayesian approach to infer the radial distribution of temperature and anisotropy in the transition zone from seismic data

    Science.gov (United States)

    Drilleau, M.; Beucler, E.; Mocquet, A.; Verhoeven, O.; Moebs, G.; Burgos, G.; Montagner, J.

    2013-12-01

    Mineralogical transformations and matter transfers within the Earth's mantle make the 350-1000 km depth range (considered here as the mantle transition zone) highly heterogeneous and anisotropic. Most of the 3-D global tomographic models are anchored on small perturbations from 1-D models such as PREM, and are secondly interpreted in terms of temperature and composition distributions. However, the degree of heterogeneity in the transition zone can be strong enough so that the concept of a 1-D reference seismic model may be addressed. To avoid the use of any seismic reference model, we developed a Markov chain Monte Carlo algorithm to directly interpret surface wave dispersion curves in terms of temperature and radial anisotropy distributions, considering a given composition of the mantle. These interpretations are based on laboratory measurements of elastic moduli and Birch-Murnaghan equation of state. An originality of the algorithm is its ability to explore both smoothly varying models and first-order discontinuities, using C1-Bézier curves, which interpolate the randomly chosen values for depth, temperature and radial anisotropy. This parameterization is able to generate a self-adapting parameter space exploration while reducing the computing time. Using a Bayesian exploration, the probability distributions on temperature and anisotropy are governed by uncertainties on the data set. The method was successfully applied to both synthetic data and real dispersion curves. Surface wave measurements along the Vanuatu- California path suggest a strong anisotropy above 400 km depth which decreases below, and a monotonous temperature distribution between 350 and 1000 km depth. On the contrary, a negative shear wave anisotropy of about 2 % is found at the top of the transition zone below Eurasia. Considering compositions ranging from piclogite to pyrolite, the overall temperature profile and temperature gradient are higher for the continental path than for the oceanic

  4. Risk assessment and early warning systems for industrial facilities in seismic zones

    International Nuclear Information System (INIS)

    Salzano, Ernesto; Garcia Agreda, Anita; Di Carluccio, Antonio; Fabbrocino, Giovanni

    2009-01-01

    Industrial equipments and systems can suffer structural damage when hit by earthquakes, so that accidental scenarios as fire, explosion and dispersion of toxic substances can take place. As a result, overall damage to people, environment and properties increases. The present paper deals with seismic risk analysis of industrial facilities where atmospheric storage tanks (anchored or unanchored to ground), horizontal pressurised tanks, reactors and pumps are installed. Simplified procedures and methodologies based on historical database and literature data on natural-technological (Na-Tech) accidents for seismic risk assessment are discussed. Equipment-specific fragility curves have been thus derived depending on a single earthquake measure, peak ground acceleration (PGA). Fragility parameters have been then transformed to linear probit coefficients in order to obtain reliable threshold values for earthquake intensity measure, both for structural damage and loss of containment. These threshold values are of great interest when development of active and passive mitigation actions and systems, safety management, and the implementation of early warning system are concerned. The approach is general and can be implemented in any available code or procedure for risk assessment. Some results of seismic analysis of atmospheric storage tanks are also presented for validation.

  5. Refraction and reflection seismic investigations for geological energy-storage site characterization: Dalby (Tornquist Zone), southwest Sweden

    Science.gov (United States)

    Malehmir, Alireza; Bergman, Bo; Andersson, Benjamin; Sturk, Robert; Johansson, Mattis

    2017-04-01

    Three high-resolution, 5 m shot and receiver spacing using 141-172 receivers, refraction and reflection seismic profiles for the planning of a major underground energy-storage site near the town of Dalby-Lund within the Scania Tornquist suture zone in southwest of Sweden were acquired during August 2015. The site is situated ca. 1 km north of the RFZ (Romeleåsen fault and flexure zone) with a complex geologic and tectonic history. Near vertical dikes are observed from several quarries in the area crosscutting granitic-gneissic-amphibiotic rocks and form clear magnetic lineaments. These dikes likely have also acted as surfaces on which further faulting have occurred. Although a major high-speed and traffic road runs in the middle of the study area, the seismic data show excellent quality particularly for the data along two profiles (profiles 2 and 3) perpendicular to the road, and slightly noisy, due to high wind, for the data along a profile (profile 4) parallel to the road. A bobcat-mounted drop hammer (500 kg) was used to generate the seismic signal. To provide continuity from one side of the road to another, 51 wireless recorders connected to 10 Hz geophones and operating in an autonomous mode were used. GPS times of the source impacts were used to extract the data from the wireless recorders and then merged with the data from the cabled recorders (also 10 Hz geophones). Three shot records per source position were generated and vertically stacked to improve the signal-to-noise ratio. First arrivals are clear in most shot gathers allowing them to be used for traditional refraction seismic data analysis and also for more advanced traveltime tomography. The velocity models obtained through traveltime tomography clearly depict bedrock surface and its undulations and in many places show good correlation with the boreholes recently drilled in the area. At places where bedrock is intersected at greater depths than usual, for example 25 m at one place, depression

  6. Structure of pseudotachylyte vein systems as a key to co-seismic rupture dynamics: the case of Gavilgarh-Tan Shear Zone, central India

    Science.gov (United States)

    Chattopadhyay, A.; Bhattacharjee, D.; Mukherjee, S.

    2014-04-01

    The secondary fractures associated with a major pseudotachylyte-bearing fault vein in the sheared aplitic granitoid of the Proterozoic Gavilgarh-Tan Shear Zone in central India are mapped at the outcrop scale. The fracture maps help to identify at least three different types of co-seismic ruptures, e.g., X-X', T1 and T2, which characterize sinistral-sense shearing of rocks, confined between two sinistral strike-slip faults slipping at seismic rate. From the asymmetric distribution of tensile fractures around the sinistral-sense fault vein, the direction of seismic rupture propagation is predicted to have occurred from west-southwest to east-northeast, during an ancient (Ordovician?) earthquake. Calculations of approximate co-seismic displacement on the faults and seismic moment ( M 0) of the earthquake are attempted, following the methods proposed by earlier workers. These estimates broadly agree to the findings from other studied fault zones (e.g., Gole Larghe Fault zone, Italian Alps). This study supports the proposition by some researchers that important seismological information can be extracted from tectonic pseudotachylytes of all ages, provided they are not reworked by subsequent tectonic activity.

  7. Seismic Tomography of the Arabian-Eurasian Collision Zone and Surrounding Areas

    National Research Council Canada - National Science Library

    Toksoz, M. N; Van der Hilst, Robert D; Sun, Youshun; Gulen, Levent; Kalafat, Dogan; Kuleli, Huseyin S; Li, Chang; Zhang, Haijiang

    2008-01-01

    ... and surrounding areas, including Iran, Arabia, Eastern Turkey, and the Caucasus. The Arabian-Eurasian plate boundary is a complex tectonic zone shaped by continent-continent collision processes...

  8. PASSEQ 2006-2008: Passive Seismic Experiment in Trans-Europe Suture ZoneI

    Czech Academy of Sciences Publication Activity Database

    Wilde-Piórko, M.; Geissler, W.H.; Plomerová, Jaroslava; Grad, M.; Babuška, Vladislav; Brückl, E.; Cyziene, J.; Czuba, W.; England, R.; Gaczyński, E.; Gaždová, Renata; Gregersen, S.; Guterch, A.; Hanka, W.; Hegedüs, E.; Heuer, B.; Jedlička, Petr; Lazauskiene, J.; Keller, G. R.; Kind, R.; Klinge, K.; Kolínský, Petr; Komminaho, K.; Kozlovskaya, E.; Krüger, F.; Larsen, T.; Majdański, M.; Málek, Jiří; Motuza, G.; Novotný, Oldřich; Pietrasiak, R.; Plenefisch, T.; Růžek, Bohuslav; Sliaupa, S.; Środa, P.; Świeczak, M.; Tiira, T.; Voss, P.; Wiejacz, P.

    2008-01-01

    Roč. 52, č. 3 (2008), s. 439-448 ISSN 0039-3169 R&D Projects: GA AV ČR IAA300120709 Institutional research plan: CEZ:AV0Z30120515; CEZ:AV0Z30460519 Keywords : lithosphere-asthenosphere system * Trans-European Suture Zone * Teisseyre- Tor nquist Zone Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.770, year: 2008

  9. Pre-seismic geomagnetic and ionosphere signatures related to the Mw5.7 earthquake occurred in Vrancea zone on September 24, 2016

    Science.gov (United States)

    Stanica, Dragos Armand; Stanica, Dumitru; Błęcki, Jan; Ernst, Tomasz; Jóźwiak, Waldemar; Słomiński, Jan

    2018-02-01

    To emphasize the relationship between the pre-seismic geomagnetic signals and Vrancea seismicity, in this work it is hypothesized that before an earthquake initiation, the high stress reached into seismogenic volume generates dehydration of the rocks and fracturing processes followed by release of electric charges along the faulting systems, which lead to resistivity changes. These changes were explored on September 2016 by the normalized function Bzn obtained from the geomagnetic data recorded in ULF range (0.001-0.0083 Hz). A statistical analysis was also performed to discriminate on the new Bzn* time series a pre-seismic signature related to the Mw5.7 earthquake. Significant anomalous behavior of Bzn* was identified on September 21, with 3 days prior to the onset of the seismic event. Similar information is provided by registrations of the magnetic and electron concentration variations in the ionosphere over the Vrancea zone, by Swarm satellites, 4 days and 1 day before the earthquake.

  10. Seismic-sequence stratigraphy and geologic structure of the Floridan aquifer system near "Boulder Zone" deep wells in Miami-Dade County, Florida

    Science.gov (United States)

    Cunningham, Kevin J.

    2015-01-01

    The U.S. Geological Survey, in cooperation with the Miami-Dade Water and Sewer Department, acquired, processed, and interpreted seismic-reflection data near the North and South District “Boulder Zone” Well Fields to determine if geologic factors may contribute to the upward migration of injected effluent into that upper part of the Floridan aquifer system designated by the U.S. Environmental Protection Agency as an underground source of drinking water. The depth of the Boulder Zone at the North and South District “Boulder Zone” Well Fields ranges from about 2,750 to 3,300 feet below land surface (ft bls), whereas overlying permeable zones used as alternative drinking water supply range in depth from about 825 to 1,580 ft bls at the North and South District “Boulder Zone” Well Fields. Seismic-sequence stratigraphy and geologic structures imaged on seismic-reflection profiles created for the study describe the part of the Floridan aquifer system overlying and within the Boulder Zone. Features of the Floridan aquifer system underlying the Boulder Zone were not studied because seismic-reflection profiles acquired near the North and South District “Boulder Zone” Well Fields lacked adequate resolution at such depths.

  11. Modeling of time-lapse multi-scale seismic monitoring of CO2 injected into a fault zone to enhance the characterization of permeability in enhanced geothermal systems

    Science.gov (United States)

    Zhang, R.; Borgia, A.; Daley, T. M.; Oldenburg, C. M.; Jung, Y.; Lee, K. J.; Doughty, C.; Altundas, B.; Chugunov, N.; Ramakrishnan, T. S.

    2017-12-01

    Subsurface permeable faults and fracture networks play a critical role for enhanced geothermal systems (EGS) by providing conduits for fluid flow. Characterization of the permeable flow paths before and after stimulation is necessary to evaluate and optimize energy extraction. To provide insight into the feasibility of using CO2 as a contrast agent to enhance fault characterization by seismic methods, we model seismic monitoring of supercritical CO2 (scCO2) injected into a fault. During the CO2 injection, the original brine is replaced by scCO2, which leads to variations in geophysical properties of the formation. To explore the technical feasibility of the approach, we present modeling results for different time-lapse seismic methods including surface seismic, vertical seismic profiling (VSP), and a cross-well survey. We simulate the injection and production of CO2 into a normal fault in a system based on the Brady's geothermal field and model pressure and saturation variations in the fault zone using TOUGH2-ECO2N. The simulation results provide changing fluid properties during the injection, such as saturation and salinity changes, which allow us to estimate corresponding changes in seismic properties of the fault and the formation. We model the response of the system to active seismic monitoring in time-lapse mode using an anisotropic finite difference method with modifications for fracture compliance. Results to date show that even narrow fault and fracture zones filled with CO2 can be better detected using the VSP and cross-well survey geometry, while it would be difficult to image the CO2 plume by using surface seismic methods.

  12. Madrid Physics Conference

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1989-11-15

    Hard on the heels of the Lepton-Photon Symposium at Stanford in August came the International Europhysics Conference on High Energy Physics in Madrid from 6-13 September. With the two meetings held so close together, there was much overlap in the physics reported, although some teams were able to use the extra month to present new results. A notable example was the Mark II team working at Stanford's SLC linear collider, who presented new limits on the number of allowed neutrinos.The Madrid meeting attracted about 600 participants from all over the world. An initial three days of parallel sessions followed by four days of plenary talks could cover the field in depth and in breadth.

  13. Prediction for potential landslide zones using seismic amplitude in Liwan gas field, northern South China Sea

    Science.gov (United States)

    Li, Xishuang; Liu, Baohua; Liu, Lejun; Zheng, Jiewen; Zhou, Songwang; Zhou, Qingjie

    2017-12-01

    The Liwan (Lw) gas field located in the northern slope of the South China Sea (SCS) is extremely complex for its sea-floor topograghy, which is a huge challenge for the safety of subsea facilities. It is economically impractical to obtain parameters for risk assessment of slope stability through a large amount of sampling over the whole field. The linkage between soil shear strength and seabed peak amplitude derived from 2D/3D seismic data is helpful for understanding the regional slope-instability risk. In this paper, the relationships among seabed peak, acoustic impedance and shear strength of shallow soil in the study area were discussed based on statistical analysis results. We obtained a similar relationship to that obtained in other deep-water areas. There is a positive correlation between seabed peak amplitude and acoustic impedance and an exponential relationship between acoustic impedance and shear strength of sediment. The acoustic impedance is the key factor linking the seismic amplitude and shear strength. Infinite slope stability analysis results indicate the areas have a high potential of shallow landslide on slopes exceeding 15° when the thickness of loose sediments exceeds 8 m in the Lw gas field. Our prediction shows that they are mainly located in the heads and walls of submarine canyons.

  14. Near-vertical seismic reflection image using a novel acquisition technique across the Vrancea Zone and Foscani Basin, south-eastern Carpathians (Romania)

    Science.gov (United States)

    Panea, I.; Stephenson, R.; Knapp, C.; Mocanu, V.; Drijkoningen, G.; Matenco, L.; Knapp, J.; Prodehl, K.

    2005-12-01

    The DACIA PLAN (Danube and Carpathian Integrated Action on Process in the Lithosphere and Neotectonics) deep seismic sounding survey was performed in August-September 2001 in south-eastern Romania, at the same time as the regional deep refraction seismic survey VRANCEA 2001. The main goal of the experiment was to obtain new information on the deep structure of the external Carpathians nappes and the architecture of Tertiary/Quaternary basins developed within and adjacent to the seismically-active Vrancea zone, including the Focsani Basin. The seismic reflection line had a WNW-ESE orientation, running from internal East Carpathians units, across the mountainous south-eastern Carpathians, and the foreland Focsani Basin towards the Danube Delta. There were 131 shot points along the profile, with about 1 km spacing, and data were recorded with stand-alone RefTek-125s (also known as "Texans"), supplied by the University Texas at El Paso and the PASSCAL Institute. The entire line was recorded in three deployments, using about 340 receivers in the first deployment and 640 receivers in each of the other two deployments. The resulting deep seismic reflection stacks, processed to 20 s along the entire profile and to 10 s in the eastern Focsani Basin, are presented here. The regional architecture of the latter, interpreted in the context of abundant independent constraint from exploration seismic and subsurface data, is well imaged. Image quality within and beneath the thrust belt is of much poorer quality. Nevertheless, there is good evidence to suggest that a thick (˜10 km) sedimentary basin having the structure of a graben and of indeterminate age underlies the westernmost part of the Focsani Basin, in the depth range 10-25 km. Most of the crustal depth seismicity observed in the Vrancea zone (as opposed to the more intense upper mantle seismicity) appears to be associated with this sedimentary basin. The sedimentary successions within this basin and other horizons

  15. Heterogeneous seismic anisotropy in the transition zone and uppermost lower mantle: evidence from South America, Izu-Bonin and Japan

    Science.gov (United States)

    Lynner, Colton; Long, Maureen D.

    2015-06-01

    Measurements of seismic anisotropy are commonly used to constrain deformation in the upper mantle. Observations of anisotropy at mid-mantle depths are, however, relatively sparse. In this study we probe the anisotropic structure of the mid-mantle (transition zone and uppermost lower mantle) beneath the Japan, Izu-Bonin, and South America subduction systems. We present source-side shear wave splitting measurements for direct teleseismic S phases from earthquakes deeper than 300 km that have been corrected for the effects of upper mantle anisotropy beneath the receiver. In each region, we observe consistent splitting with delay times as large as 1 s, indicating the presence of anisotropy at mid-mantle depths. Clear splitting of phases originating from depths as great as ˜600 km argues for a contribution from anisotropy in the uppermost lower mantle as well as the transition zone. Beneath Japan, fast splitting directions are perpendicular or oblique to the slab strike and do not appear to depend on the propagation direction of the waves. Beneath South America and Izu-Bonin, splitting directions vary from trench-parallel to trench-perpendicular and have an azimuthal dependence, indicating lateral heterogeneity. Our results provide evidence for the presence of laterally variable anisotropy and are indicative of variable deformation and dynamics at mid-mantle depths in the vicinity of subducting slabs.

  16. Basic data features and results from a spatially dense seismic array on the San Jacinto fault zone

    Science.gov (United States)

    Ben-Zion, Yehuda; Vernon, Frank L.; Ozakin, Yaman; Zigone, Dimitri; Ross, Zachary E.; Meng, Haoran; White, Malcolm; Reyes, Juan; Hollis, Dan; Barklage, Mitchell

    2015-07-01

    We discuss several outstanding aspects of seismograms recorded during >4 weeks by a spatially dense Nodal array, straddling the damage zone of the San Jacinto fault in southern California, and some example results. The waveforms contain numerous spikes and bursts of high-frequency waves (up to the recorded 200 Hz) produced in part by minute failure events in the shallow crust. The high spatial density of the array facilitates the detection of 120 small local earthquakes in a single day, most of which not detected by the surrounding ANZA and regional southern California networks. Beamforming results identify likely ongoing cultural noise sources dominant in the frequency range 1-10 Hz and likely ongoing earthquake sources dominant in the frequency range 20-40 Hz. Matched-field processing and back-projection of seismograms provide alternate event location. The median noise levels during the experiment at different stations, waves generated by Betsy gunshots, and wavefields from nearby earthquakes point consistently to several structural units across the fault. Seismic trapping structure and local sedimentary basin produce localized motion amplification and stronger attenuation than adjacent regions. Cross correlations of high-frequency noise recorded at closely spaced stations provide a structural image of the subsurface material across the fault zone. The high spatial density and broad frequency range of the data can be used for additional high resolution studies of structure and source properties in the shallow crust.

  17. Towards a Detailed Seismic Structure of the Valley of Mexico's Xochimilco Lake Zone.

    Science.gov (United States)

    Rabade, S.; Sanchez-Sanchez, J.; Ayala Hernandez, M.; Macias, M. A.; Aguilar Calderon, L. A.; Alcántara, L.; Almora Mata, D.; Castro Parra, G.; Delgado, R.; Leonardo Suárez, M.; Molina Avila, I.; Mora, A.; Perez-Yanez, C.; Ruiz, A. L.; Sandoval, H.; Torres Noguez, M.; Vazquez Larquet, R.; Velasco Miranda, J. M.; Aguirre, J.; Ramirez-Guzmán, L.

    2017-12-01

    Six centuries of gradual, intentional sediment filling in the Xochimilco Lake Zone have drastically reduced the size of the lake. The basin structure and the lake's clay limits and thickness are poorly constrained, and yet, essential to explain the city's anomalous ground motion. Therefore, we conducted an experiment to define the 3D velocity model of Mexico's capital; the CDMX-E3D. The initial phase involved the deployment of a moving set of 18-broadband stations with an interstation distance of 500m over a period of 19 weeks. We collected the data and analyzed the results for the Xochimilco Lake Zone using H/V Spectral Ratios (Nakamura, 1989), which provided an improved fundamental period map of the region. Results show that periods in the former lake zone have larger variability than values previously estimated. In order to obtain group velocity maps at different periods, we estimated Green's functions from ambient noise cross-correlations following standard methodologies to invert Rayleigh wave travel times (Bensen et al., 2007). Preliminary result show very low-velocity zones (100 m/s) and thick sediment layers in most of the former Xochimilco Lake area. This Project was funded by the Secretaria de Ciencia, Tecnología e Innovación (SECITI) of Mexico City. Project SECITI/073/2016.

  18. Magmatism and underplating, a broadband seismic perspective on the Proterozoic tectonics of the Great Falls and Snowbird Tectonic Zones

    Science.gov (United States)

    Chen, Y.; Gu, Y. J.; Dokht, R.; Wang, R.

    2017-12-01

    The crustal and lithospheric structures beneath the Western Canada Sedimentary Basin (WCSB) and northern Montana contain vital records of the Precambrian tectonic development of Laurentia. In this study, we analyze the broadband seismic data recorded by the USArray and the most complete set of regional seismic networks to date near the WCSB. We adopt an integrated approach to investigate crustal structure and history, based primarily on P-to-S receiver functions but incorporate results from noise correlation functions, finite-frequency tomography and potential field measurements. In comparison with existing regional and global models, our stacked receiver functions show considerable improvements in the resolution of both Moho depth and Vp/Vs ratio. We identify major variations in Moho depth from the WCSB to the adjacent Cordillera. The Moho deepens steeply from 40 km in the Alberta basin to 50 km beneath the foothills, following Airy isostasy, but thermal buoyancy may be responsible for a flat, shallow ( 35 km) Moho to the west of the Rocky Mountain Trench. The Moho depth also increases sharply near the Snowbird Tectonic Zone (STZ), which is consistent with earlier findings from active-source data. Multiple lower crustal phases, a high velocity shallow mantle and elevated Vp/Vs ratios along the westernmost STZ jointly suggest major Proterozoic subduction and magmatism along this collisional boundary. In northern Montana, the Moho deepens along the Great Falls Tectonic Zone (GFTZ), a proposed Proterozoic suture between the Medicine Hat Block and Wyoming craton. This transition occurs near the Little Belt Mountain, which is located south of the Great Falls Shear Zone, an extensive northeast striking fault system characterized by strong potential field gradients. Similar to the STZ, our receiver functions offer new evidence for Proterozoic underplating in the vicinity of the GFTZ. In view of similar rock ages near the collisional boundaries in all parts of northern

  19. The Social ecology of Madrid: Stratification in comparative perspective.

    Science.gov (United States)

    Abrahamson, M; Johnson, P

    1974-08-01

    This paper examines the characteristics of residential zones in Madrid, Spain. The primary difference between zones is found to lie in a new bourgeoisie life-style dimension. Working women are found to be the best indicator of this dimension, which also involves servants, natives of Madrid and high degrees of literacy. Fertility-related considerations, however, are unrelated to working women, and this is explained as due to the availability of domestic help and "women-oriented" working arrangements. Fertility and socioeconomic status are found to be interrelated and constitute a second dimension of residential segregation. In conclusion, Madrid is examined in relation to both more and less industrialized cities, leading to a further modification of social area theory contentions concerning the ecology of stratification in developing cities.

  20. Intermediate-term earthquake prediction and seismic zoning in Northern Italy

    International Nuclear Information System (INIS)

    Panza, G.F.; Orozova Stanishkova, I.; Costa, G.; Vaccari, F.

    1993-12-01

    The algorithm CN for intermediate earthquake prediction has been applied to an area in Northern Italy, which has been chosen according to a recently proposed seismotectonic model. Earthquakes with magnitude ≥ 5.4 occur in the area with a relevant frequency and their occurrence is predicted by algorithm CN. Therefore a seismic hazard analysis has been performed using a deterministic procedure, based on the computation of complete synthetic seismograms. The results are summarized in a map giving the distribution of peak ground acceleration, but the complete time series are available, which can be used by civil engineers in the design of new seismo-resistant constructions and in the retrofitting of the existing ones. This risk reduction action should be intensified in connection with warnings issued on the basis of the forward predictions made by CN. (author). Refs, 7 figs, 1 tab

  1. High Resolution Seismic Images of Transition Zone Discontinuities beneath the Hawaii-Emperor Seamount Chain

    Science.gov (United States)

    Cao, Q.; Wang, P.; van der Hilst, R. D.; Shim, S.

    2009-12-01

    Taking advantage of the abundance of natural sources (earthquakes) in western Pacific subduction zones and the many seismograph stations in the Americas, we use inverse scattering - a generalized Radon transform - of SS precursors to image the transition zone discontinuities underneath Hawaii and the Hawaii-Emperor seamount chain. The GRT makes use of scattering theory and extracts structural information from broad band data windows that include precursors to SS (which are the specular reflections at the discontinuities that form the main arrivals) as well as non-specular scattered energy (which is often discarded as noise). More than 150,000 seismograms (from the IRIS Data Management Center) are used to form a 3-D image of the transition zone discontinuities beneath the central Pacific. In addition to clear signals near 410, 520, and 660 km depth, the data also reveal scatter interfaces near 370 km dept and between 800-1000 km depth, which may be regional, laterally intermittent scatter horizons. Our images reveal a conspicuous uplift of the 660 discontinuity in a region of 800km in diameter to the west of the active volcanoes of Hawaii. No correspondent localized depression of the 410 discontinuity is found. Instead, we find a smaller scale anomaly suggesting that the 410 discontinuity is locally elevated in the same region. This may indicate the presence of melt or minor chemical constitutes. The lack of correlation between and differences in lateral length scale of the topographies of the 410 and 660 km discontinuities are also consistent with a deep-mantle plume impinging on the transition zone, creating a pond of hot material underneath 660 discontinuity, and with secondary plumes connecting to the present-day hotspot at Earth’s surface. Our observations suggest that more complicated plume morphology and plume dynamics within the Earth's mantle should be taken into account to describe the plumes and, in particular, mass transport across the transition zone

  2. A 80 OBS and 30 Land 3-component seismometers array encompassing the 280 km segment of the Lesser Antilles subduction megathrust seismogenic zone: view of current seismicity

    Science.gov (United States)

    Laigle, Mireille; Sapin, Martine; Ruiz, Mario; Diaz, Jordi; Kissling, Edi; Charvis, Philippe; Flueh, Ernst; Hirn, Alfred

    2010-05-01

    An extensive onshore and offshore seismic station array in the Lesser Antilles subduction zone allows to monitor microearthquake activity for a period of 4 months in a region previously outside of reach for detailed observation. Such a network has been possible thanks to a cluster of 3 seismic surveys (TRAIL - F/S Merian, SISMANTILLESII - N/O Atalante, and OBSANTILLES - N/O Antea) for deploying and recovering the instruments from several pools (Geoazur, INSU-IPGP, IFM-GEOMAR, AWI ). It has been followed by an additional deployment of the 28 GeoAzur OBSs (OBSANTILLES - N/O Antea) during 5 months in the south-western half. These operations have been carried out for the seismic investigation of the Antilles megathrust seismogenic zone in the framework of the THALES WAS RIGHT european project, and with also the financial support of the french ANR Catastrophes Telluriques et Tsunamis (SUBSISMANTI) and by the EU SALVADOR Programme of IFM-GEOMAR. Onshore, 30 3-components land stations (CSIC Barcelone, IPG Paris, INSU-RLBM and -LITHOSCOPE) have been temporarily deployed. The deep seismic structure of the whole area has been investigated during these seismic surveys by wide-angle reflection and refraction seismics recorded by these instruments as well as multi-channel reflection seismic imaging (MCS) along a dense grid of crossing profiles at the OBS positions providing excellent velocity information for the upper plate. Both the location and the interpretation of the recorded earthquake activity require constraints on the deep seismic structure, which will be discussed with respect to the 3D geometry of the interplate boundary and oceanic Moho, as well as those of the forearc basement and Moho. Preliminary locations have been obtained within a simple 1D velocity model by taking into account corrections for the variable thickness of the mud- and sediments layers beneath each OBS. The latter are estimated for both P- and S-waves to compensate for the huge structural

  3. Validation of tectonic models for an intraplate seismic zone, Charleston, South Carolina, with GPS geodetic data

    International Nuclear Information System (INIS)

    Talwani, P.; Kellogg, J.N.; Trenkamp, R.

    1997-02-01

    Although the average strain rate in intraplate settings is 2--3 orders of magnitude lower than at plate boundaries, there are pockets of high strain rates within intraplate regions. The results of a Global Positioning System survey near the location of current seismicity (and the inferred location of the destructive 1886 Charleston, South Carolina earthquake) suggest that there is anomalous strain build-up occurring there. By reoccupying 1930 triangulation and 1980 GPS sites with six Trimble SST dual frequency receivers, a strain rate of 0.4 x 10 -7 yr -1 was observed. At the 95% confidence level, this value is not significant; however, at a lower level of confidence (∼ 85%) it is about two orders of magnitude greater than the background of 10 -9 to 10 -10 yr -1 . The direction of contraction inferred from the GPS survey 66 degree ± 11 degree is in excellent agreement with the direction of the maximum horizontal stress (N 60 degree E) in the area, suggesting that the observed strain rate is also real. 66 refs

  4. Seismic Imaging of the Lesser Antilles Subduction Zone Using S-to-P Receiver Functions: Insights From VoiLA

    Science.gov (United States)

    Chichester, B.; Rychert, C.; Harmon, N.; Rietbrock, A.; Collier, J.; Henstock, T.; Goes, S. D. B.; Kendall, J. M.; Krueger, F.

    2017-12-01

    In the Lesser Antilles subduction zone Atlantic oceanic lithosphere, expected to be highly hydrated, is being subducted beneath the Caribbean plate. Water and other volatiles from the down-going plate are released and cause the overlying mantle to melt, feeding volcanoes with magma and hence forming the volcanic island arc. However, the depths and pathways of volatiles and melt within the mantle wedge are not well known. Here, we use S-to-P receiver functions to image seismic velocity contrasts with depth within the subduction zone in order to constrain the release of volatiles and the presence of melt in the mantle wedge, as well as slab structure and arc-lithosphere structure. We use data from 55-80° epicentral distances recorded by 32 recovered broadband ocean-bottom seismometers that were deployed during the 2016-2017 Volatiles in the Lesser Antilles (VoiLA) project for 15 months on the back- and fore-arc. The S-to-P receiver functions are calculated using two methods: extended time multi-taper deconvolution followed by migration to depth to constrain 3-D discontinuity structure of the subduction zone; and simultaneous deconvolution to determine structure beneath single stations. In the south of the island arc, we image a velocity increase with depth associated with the Moho at depths of 32-40 ± 4 km on the fore- and back-arc, consistent with various previous studies. At depths of 65-80 ± 4 km beneath the fore-arc we image a strong velocity decrease with depth that is west-dipping. At 96-120 ± 5 km beneath the fore-arc, we image a velocity increase with depth that is also west-dipping. The dipping negative-positive phase could represent velocity contrasts related to the top of the down-going plate, a feature commonly imaged in subduction zone receiver function studies. The negative phase is strong, so there may also be contributions to the negative velocity discontinuity from slab dehydration and/or mantle wedge serpentinization in the fore-arc.

  5. Characteristics of Conducting the Multi-Component Seismic Prospecting in the Transition Zone in Conditions of Very Shallow Water of Arctic Seas

    Directory of Open Access Journals (Sweden)

    I. A. Matveev

    2017-12-01

    Full Text Available Transition zones of transition from land to sea are the areas where it is extremely difficult to conduct geophysical works with conventional methods. In the Arctic seas of Russia, there are additional difficulties associated with the short field season, unfavorable hydrometeorological conditions, and severe restrictions imposed on the methodology and acquisition techniques by requirements of the environmental nature protection legislation. To obtain high-quality seismic data it is extremely important to select the most suitable equipment for data acquisition, optimal shooting geometry and data acquisition methodology, and the most advanced data processing and quality control software. The purpose of this article is to show developed at JSC MAGE 4-component 2D seismic technology based on use of the autonomous bottom stations. It allows conducting the seismic regional 2D survey in the transit area with registration of converted (PS waves at higher efficiency level.

  6. Seismic attribute detection of faults and fluid pathways within an active strike-slip shear zone: New insights from high-resolution 3D P-Cable™ seismic data along the Hosgri Fault, offshore California

    Science.gov (United States)

    Kluesner, Jared W.; Brothers, Daniel

    2016-01-01

    Poststack data conditioning and neural-network seismic attribute workflows are used to detect and visualize faulting and fluid migration pathways within a 13.7 km2 13.7 km2 3D P-Cable™ seismic volume located along the Hosgri Fault Zone offshore central California. The high-resolution 3D volume used in this study was collected in 2012 as part of Pacific Gas and Electric’s Central California Seismic Imaging Project. Three-dimensional seismic reflection data were acquired using a triple-plate boomer source (1.75 kJ) and a short-offset, 14-streamer, P-Cable system. The high-resolution seismic data were processed into a prestack time-migrated 3D volume and publically released in 2014. Postprocessing, we employed dip-steering (dip and azimuth) and structural filtering to enhance laterally continuous events and remove random noise and acquisition artifacts. In addition, the structural filtering was used to enhance laterally continuous edges, such as faults. Following data conditioning, neural-network based meta-attribute workflows were used to detect and visualize faults and probable fluid-migration pathways within the 3D seismic volume. The workflow used in this study clearly illustrates the utility of advanced attribute analysis applied to high-resolution 3D P-Cable data. For example, results from the fault attribute workflow reveal a network of splayed and convergent fault strands within an approximately 1.3 km wide shear zone that is characterized by distinctive sections of transpressional and transtensional dominance. Neural-network chimney attribute calculations indicate that fluids are concentrated along discrete faults in the transtensional zones, but appear to be more broadly distributed amongst fault bounded anticlines and structurally controlled traps in the transpressional zones. These results provide high-resolution, 3D constraints on the relationships between strike-slip fault mechanics, substrate deformation, and fluid migration along an active

  7. Seismic micro-zoning in the alpine valleys and local application in urban planning regulations

    Directory of Open Access Journals (Sweden)

    Stéphane Cartier

    2009-03-01

    Full Text Available Confrontées au risque sismique, les vallées sédimentaires alpines testent différentes solutions politiques pour transcrire en règles d’urbanisme les connaissances apportées par les micro-zonages. France, Italie, Slovénie et Suisse composent avec leur tradition politique et l’adoption de codes européens pour améliorer la sécurité selon la vulnérabilité et la géologie locales.Management of earthquake risks in the sedimentary valleys of the Alps depends on the ability to transcribe scientific knowledge obtained from micro-zoning into urban planning regulations. France, Italy, Slovenia and Switzerland are working with new European codes, and within their respective political contexts, to improve earthquake safety on the basis of enhanced input on local geological conditions and vulnerability levels.

  8. Late Quaternary paleoseismicity and seismic potential of the Yilan-Yitong Fault Zone in NE China

    Science.gov (United States)

    Yu, Zhongyuan; Yin, Na; Shu, Peng; Li, Jincheng; Wei, Qinghai; Min, Wei; Zhang, Peizhen

    2018-01-01

    The Yilan-Yitong Fault Zone (YYFZ), which is composed of two nearly parallel branches with a spacing of 5-30 km and a length of ∼1100 km, is considered to be the key branch of the Tancheng-Lujiang Fault Zone (TLFZ) in NE China. It was traditionally believed that the YYFZ experienced weak activity or was inactive during the Late Quaternary, without the capability to generate strong earthquakes (M ≥ 7), based on the absence of typical outcrops and large historical or instrumental earthquakes (M > 6). However, our paleoseismic study shows that the YYFZ is the primary seismotectonic structure (M ≥ 7) that poses significant earthquake threats to NE China. The synthesis of data collected from geologic investigations, geomorphic mapping, trench logging and the dating of samples indicates that the YYFZ is an active structure that has undergone segmented strong tectonic deformation since the Late Quaternary with a characteristic assemblage of landforms, including linear scarps and troughs, offset or deflected streams, linear sag ponds, small horsts and grabens. The latest ruptures of the YYFZ migrated from previous boundary faults into the basin interior, forming a left-stepping en echelon pattern in plain view, and the kinematics of these events in the Late Quaternary were dominated by reverse dextral slipping. Multi-segment cluster faulting might have occurred during three cluster periods, i.e., ∼34750-35812 a BP, ∼21700-22640 a BP, and ∼4000 a BP-present, which implies that the recurrence interval of large earthquakes along the YYFZ may be as long as tens of thousands of years.

  9. Dehydration kinetics of talc and 10 Å phase: Consequences for subduction zone seismicity

    Science.gov (United States)

    Chollet, Mélanie; Daniel, Isabelle; Koga, Kenneth T.; Petitgirard, Sylvain; Morard, Guillaume

    2009-06-01

    The process of dehydration embrittlement is usually proposed as an explanation for the presence of intermediate-depth earthquakes in subduction zones. It assumes that the release of water by hydrous mineral breakdown is fast enough to provoke brittle failure. We performed high-pressure, high-temperature, dehydration experiments of talc and 10 Å phase coupled with in situ measurement of reaction kinetics using synchrotron X-ray diffraction. Newly developed, X-ray transparent, pressure-sealed, titanium capsule ensured a closed thermochemical environment. From isothermal kinetics data fitted to the Avrami's equation and from the texture of reaction products, we conclude that dehydration rates of these minerals are limited by diffusion. Predicted minimum rates of fluid release range from 10 - 4 to 9 × 10 - 6 m 3fluid m - 3 rock s - 1 , and are fast enough to provoke hydraulic rupture since Maxwell relaxation rate of rocks relevant of subduction zones are slower than the rate of fluid release. These rates are comparable between talc, 10 Å phase and antigorite also [Perrillat, J.-P., Daniel, I., Koga, K.T., Reynard, B., Cardon, H., Crichton, W.A., 2005. Kinetics of antigorite dehydration: a real-time X-ray diffraction study. Earth Planet. Sci. Lett. 236, 899-913]. Consequently, we suggest that the dehydration of hydrous minerals may eventually be fast enough to trigger the intermediate-depth earthquakes, and that the deepest among intermediate-depth earthquakes may actually locate the limits for dehydration of hydrous minerals in the downgoing lithosphere.

  10. Complex Morphology of Subducted Lithosphere in the Mantle below the Molucca Collision Zone from Non-linear Seismic Tomography

    Directory of Open Access Journals (Sweden)

    Sri Widiyantoro

    2003-05-01

    Full Text Available Results of seismic studies presented in previous publications depict two opposing subducted oceanic lithospheric slabs under the Molucca region. This unique structure is related to the arc-arc collision between the Halmahera and Sangihe arcs. Recently, we have revisited the complex subduction zone structure by employing a non-linear tomographic imaging technique in which 3-D ray tracing has been implemented. We have used P- as well as S-wave arrival times from carefully reprocessed global data set. The results provide some improvements in the positioning of wave-speed anomalies. Consistent with earlier results, the new P-wave model depicts the two opposing subducted slabs of the Molucca Sea plate. The intriguing new observation is that the westward dipping slab appears to penetrate into the lower mantle by taking the form of folded slab. We envisage that the folding behavior may have been caused by the shift of the whole subduction system in the Molucca region toward the Eurasian continent due to the westward thrust of the Pacific plate combined with the large left-lateral movement of the Sorong fault. The inversion of travel-time residuals of direct S phases strongly confirms the new observation.

  11. Impact of The N - S Fracture Zone Along The Indo-Australia Plate Analyzed from Local Seismic Data In The Western Offshore of Sumatra, Indonesia

    Science.gov (United States)

    Haridhi, H. A.; Klingelhoefer, F.; Huang, B. S.; Lee, C. S.

    2015-12-01

    Large subduction earthquake have repeatedly occurred along the Sumatra and Andaman subduction zones where the Indo-Australia plate is subducting beneath the Eurasian plate. We have analyzed earthquake data from local seismic network along the Sumatra region that provided by the Meteorology Climatology Geophysical Agencies of Indonesia (MCGAI), giving a reliable P-wave velocity model by using joint inversion of picked P-wave travel time using VELEST and a re-scanned single channel seismic reflection of Sumatra cruise I and II. As much as 1,503 events are being analyzed, that is from two years and three months of data recording (2009/04 - 2011/07). The VELEST and DD technique are used to relocate all events by forcing the obtained velocity model. It is found that the surface deformation and earthquake cluster are strongly influenced by the impact of an N - S subparalel fracture zone along the Indo-Australia plate. This also explains the seismic gaps along the Sumatra and Andaman subduction zones. So far, the intriguing seismogenic behaviour and forearc structure are not well explained by the existing models. Therefore, the planned IODP Expedition 362 is trying to ground truth the scientific questions. The aftershock earthquake data are huge, but they will provide a gateway to help the understanding of this shallow megathrust slip and reduce its devastated harzards.

  12. Three-dimensional Seismic Survey of the Continental-Ocean Transition Zone of the Northern South China Sea

    Science.gov (United States)

    Zhao, M.; Wang, Q.; Sibuet, J. C.; Sun, L.; Sun, Z.; Qiu, X.

    2017-12-01

    The South China Sea (SCS) is one of the largest marginal seas in the western Pacific, which has experienced extension, rifting, breakup, post-spreading magmatism on its northern margin during the Cenozoic era. The complexity of this margin is exacerbated by rifting and seafloor spreading processes, which developed at the expenses of the subducting proto-South China Sea. Based on Sun et al. (2014, 2016) proposals, 6 sites were drilled on the northern SCS margin from February to June 2017, during IODP Expeditions 367/368. The preliminary results indicate that the width of the COT is about 20 km and is different from the typical magma-poor Iberia margin whose width is around 100 km. The combination of three-dimensional (3D) Ocean Bottom Seismometers (OBS) refractive survey with IODP drilling results, will improve the drilling achievement and greatly contribute to the understanding of the specific mechanism of rifting and breakup processes of the northern SCS. In particular, it is expected to constrain: 1) the nature of the crust in the COT, 2) the degree of serpentinization of the upper mantle beneath the COT, and 3) the 3D extension of the COT, the oceanic crust and the serpentinized mantle. We firstly carry out the resolution tests and calculate the interval of OBSs using a ray tracing and travel time modelling software. 7-km interval between OBSs is the optimal interval for the resolution tests and ray coverage, which will provide optimal constraints for the characterization of the 20-km wide COT. The 3D seismic survey will be carried out in 2018. The design of the OBSs arrangement and the location of shooting lines are extremely important. At present, we propose 5 main profiles and 14 shooting lines along the multi-channel seismic lines already acquired in the vicinity of the 6 drilling sites. Any comments and suggestions concerning the OBSs arrangement will be appreciated. This work is supported by the Chinese National Natural Science Foundation (contracts

  13. Suitability of Open-Ocean Instrumentation for Use in Near-Field Tsunami Early Warning Along Seismically Active Subduction Zones

    Science.gov (United States)

    Williamson, Amy L.; Newman, Andrew V.

    2018-05-01

    Over the past decade, the number of open-ocean gauges capable of parsing information about a passing tsunami has steadily increased, particularly through national cable networks and international buoyed efforts such as the Deep-ocean Assessment and Reporting of Tsunami (DART). This information is analyzed to disseminate tsunami warnings to affected regions. However, most current warnings that incorporate tsunami are directed at mid- and far-field localities. In this study, we analyze the region surrounding four seismically active subduction zones, Cascadia, Japan, Chile, and Java, for their potential to facilitate local tsunami early warning using such systems. We assess which locations currently have instrumentation in the right locations for direct tsunami observations with enough time to provide useful warning to the nearest affected coastline—and which are poorly suited for such systems. Our primary findings are that while some regions are ill-suited for this type of early warning, such as the coastlines of Chile, other localities, like Java, Indonesia, could incorporate direct tsunami observations into their hazard forecasts with enough lead time to be effective for coastal community emergency response. We take into account the effect of tsunami propagation with regard to shallow bathymetry on the fore-arc as well as the effect of earthquake source placement. While it is impossible to account for every type of off-shore tsunamigenic event in these locales, this study aims to characterize a typical large tsunamigenic event occurring in the shallow part of the megathrust as a guide in what is feasible with early tsunami warning.

  14. Cenozoic pulsed compression of Da'an-Dedu Fault Zone in Songliao Basin (NE China) and its implications for earthquake potential: Evidence from seismic data

    Science.gov (United States)

    Yu, Zhongyuan; Zhang, Peizhen; Min, Wei; Wei, Qinghai; Zhao, Bin

    2018-01-01

    The Da'an-Dedu Fault Zone (DDFZ) is a major tectonic feature cutting through the Songliao Basin from south to north in NE China. Pulsed compression deformation of DDFZ during the Cenozoic implies a complex geodynamic process, and the latest stage of which occurred in the Quaternary directly influences the present seismicity of the interior basin. Although most of the evidence for Quaternary deformation about the Songliao Basin in the past decades was concentrated in marginal faults, all five earthquake swarms with magnitudes over 5.0 along the buried DDFZ with no surface expression during the past 30 years suggest it is a main seismogenic structure with seismic potential, which should deserve more attention of geologists. However, limited by the coverage of the Quaternary sedimentary and absence of strong historic and instrumental earthquakes records (M > 7), the geometric pattern, Quaternary activity and seismic potential of the DDFZ remain poorly understood. Thus, unlike previous geophysical studies focused on crust/mantle velocity structure across the fault and the aim of exploring possible mineral resources in the basin, in this study we have integrated a variety of the latest seismic data and drilling holes from petroleum explorations and shallow-depth seismic reflection profiles, to recognize the Cenozoic pulsed compression deformation of the DDFZ, and to discuss its implication for earthquake potential. The results show that at least four stages of compression deformation have occurred along the DDFZ in the Cenozoic: 65 Ma, 23 Ma, 5.3 Ma, and 1.8 Ma, respectively, although the geodynamic process behind which still in dispute. The results also imply that the tectonic style of the DDFZ fits well with the occurrence of modern seismic swarms. Moderate earthquake potential (M ≤ 7.0) is suggested along the DDFZ.

  15. Lateral variations of the Guerrero-Oaxaca subduction zone (Mexico) derived from weak seismicity (Mb3.5+) detected on a single array at teleseismic distance

    Science.gov (United States)

    Letort, Jean; Retailleau, Lise; Boué, Pierre; Radiguet, Mathilde; Gardonio, Blandine; Cotton, Fabrice; Campillo, Michel

    2018-05-01

    Detections of pP and sP phase arrivals (the so-called depth phases) at teleseismic distance provide one of the best ways to estimate earthquake focal depth, as the P-pP and the P-sP delays are strongly dependent on the depth. Based on a new processing workflow and using a single seismic array at teleseismic distance, we can estimate the depth of clusters of small events down to magnitude Mb 3.5. Our method provides a direct view of the relative variations of the seismicity depth from an active area. This study focuses on the application of this new methodology to study the lateral variations of the Guerrero subduction zone (Mexico) using the Eielson seismic array in Alaska (USA). After denoising the signals, 1232 Mb 3.5 + events were detected, with clear P, pP, sP and PcP arrivals. A high-resolution view of the lateral variations of the depth of the seismicity of the Guerero-Oaxaca area is thus obtained. The seismicity is shown to be mainly clustered along the interface, coherently following the geometry of the plate as constrained by the receiver-function analysis along the Meso America Subduction Experiment profile. From this study, the hypothesis of tears on the western part of Guerrero and the eastern part of Oaxaca are strongly confirmed by dramatic lateral changes in the depth of the earthquake clusters. The presence of these two tears might explain the observed lateral variations in seismicity, which is correlated with the boundaries of the slow slip events.

  16. Structural analysis of S-wave seismics around an urban sinkhole: evidence of enhanced dissolution in a strike-slip fault zone

    Science.gov (United States)

    Wadas, Sonja H.; Tanner, David C.; Polom, Ulrich; Krawczyk, Charlotte M.

    2017-12-01

    In November 2010, a large sinkhole opened up in the urban area of Schmalkalden, Germany. To determine the key factors which benefited the development of this collapse structure and therefore the dissolution, we carried out several shear-wave reflection-seismic profiles around the sinkhole. In the seismic sections we see evidence of the Mesozoic tectonic movement in the form of a NW-SE striking, dextral strike-slip fault, known as the Heßleser Fault, which faulted and fractured the subsurface below the town. The strike-slip faulting created a zone of small blocks ( sinkholes and dissolution-induced depressions. Since the processes are still ongoing, the occurrence of a new sinkhole cannot be ruled out. This case study demonstrates how S-wave seismics can characterize a sinkhole and, together with geological information, can be used to study the processes that result in sinkhole formation, such as a near-surface fault zone located in soluble rocks. The more complex the fault geometry and interaction between faults, the more prone an area is to sinkhole occurrence.

  17. Angola Seismicity MAP

    Science.gov (United States)

    Neto, F. A. P.; Franca, G.

    2014-12-01

    The purpose of this job was to study and document the Angola natural seismicity, establishment of the first database seismic data to facilitate consultation and search for information on seismic activity in the country. The study was conducted based on query reports produced by National Institute of Meteorology and Geophysics (INAMET) 1968 to 2014 with emphasis to the work presented by Moreira (1968), that defined six seismogenic zones from macro seismic data, with highlighting is Zone of Sá da Bandeira (Lubango)-Chibemba-Oncócua-Iona. This is the most important of Angola seismic zone, covering the epicentral Quihita and Iona regions, geologically characterized by transcontinental structure tectono-magmatic activation of the Mesozoic with the installation of a wide variety of intrusive rocks of ultrabasic-alkaline composition, basic and alkaline, kimberlites and carbonatites, strongly marked by intense tectonism, presenting with several faults and fractures (locally called corredor de Lucapa). The earthquake of May 9, 1948 reached intensity VI on the Mercalli-Sieberg scale (MCS) in the locality of Quihita, and seismic active of Iona January 15, 1964, the main shock hit the grade VI-VII. Although not having significant seismicity rate can not be neglected, the other five zone are: Cassongue-Ganda-Massano de Amorim; Lola-Quilengues-Caluquembe; Gago Coutinho-zone; Cuima-Cachingues-Cambândua; The Upper Zambezi zone. We also analyzed technical reports on the seismicity of the middle Kwanza produced by Hidroproekt (GAMEK) region as well as international seismic bulletins of the International Seismological Centre (ISC), United States Geological Survey (USGS), and these data served for instrumental location of the epicenters. All compiled information made possible the creation of the First datbase of seismic data for Angola, preparing the map of seismicity with the reconfirmation of the main seismic zones defined by Moreira (1968) and the identification of a new seismic

  18. Temporal variations of the fractal properties of seismicity in the western part of the north Anatolian fault zone: possible artifacts due to improvements in station coverage

    Directory of Open Access Journals (Sweden)

    A. O. Öncel

    1995-01-01

    Full Text Available Seismically-active fault zones are complex natural systems exhibiting scale-invariant or fractal correlation between earthquakes in space and time, and a power-law scaling of fault length or earthquake source dimension consistent with the exponent b of the Gutenberg-Richter frequency-magnitude relation. The fractal dimension of seismicity is a measure of the degree of both the heterogeneity of the process (whether fixed or self-generated and the clustering of seismic activity. Temporal variations of the b-value and the two-point fractal (correlation dimension Dc have been related to the preparation process for natural earthquakes and rock fracture in the laboratory These statistical scaling properties of seismicity may therefore have the potential at least to be sensitive short- term predictors of major earthquakes. The North Anatolian Fault Zone (NAFZ is a seismicallyactive dextral strike slip fault zone which forms the northern boundary of the westward moving Anatolian plate. It is splayed into three branches at about 31oE and continues westward toward the northern Aegean sea. In this study, we investigate the temporal variation of Dc and the Gutenberg-Richter b-value for seismicity in the western part of the NAFZ (including the northern Aegean sea for earthquakes of Ms > 4.5 occurring in the period between 1900 and 1992. b ranges from 0.6-1.6 and Dc from 0.6 to 1.4. The b-value is found to be weakly negatively correlated with Dc (r=-0.56. However the (log of event rate N is positively correlated with b, with a similar degree of statistical significance (r=0.42, and negatively correlated with Dc (r=-0.48. Since N increases dramatically with improved station coverage since 1970, the observed negative correlation between b and Dc is therefore more likely to be due to this effect than any underlying physical process in this case. We present this as an example of how man-made artefacts of recording can have similar statistical effects to

  19. Formation of diapiric structure in the deformation zone, central Indian Ocean: A model from gravity and seismic reflection data

    Digital Repository Service at National Institute of Oceanography (India)

    Krishna, K.S.; Rao, D.G.; Neprochnov, Y.P.

    Analyses of bathymetry, gravity and seismic reflection data of the diffusive plate boundary in the central Indian Ocean reveal a new kind of deformed structure besides the well-reported structures of long-wavelength anticlinal basement rises...

  20. Coulomb Stress Change and Seismic Hazard of Rift Zones in Southern Tibet after the 2015 Mw7.8 Nepal Earthquake and Its Mw7.3 Aftershock

    Science.gov (United States)

    Dai, Z.; Zha, X.; Lu, Z.

    2015-12-01

    In southern Tibet (30~34N, 80~95E), many north-trending rifts, such as Yadong-Gulu and Lunggar rifts, are characterized by internally drained graben or half-graben basins bounded by active normal faults. Some developed rifts have become a portion of important transportation lines in Tibet, China. Since 1976, eighty-seven >Mw5.0 earthquakes have happened in the rift regions, and fifty-five events have normal faulting focal mechanisms according to the GCMT catalog. These rifts and normal faults are associated with both the EW-trending extension of the southern Tibet and the convergence between Indian and Tibet. The 2015 Mw7.8 Nepal great earthquake and its Mw7.3 aftershock occurred at the main Himalayan Thrust zone and caused tremendous damages in Kathmandu region. Those earthquakes will lead to significant viscoelastic deformation and stress changes in the southern Tibet in the future. To evaluate the seismic hazard in the active rift regions in southern Tibet, we modeled the slip distribution of the 2015 Nepal great earthquakes using the InSAR displacement field from the ALOS-2 satellite SAR data, and calculated the Coulomb failure stress (CFS) on these active normal faults in the rift zones. Because the estimated CFS depends on the geometrical parameters of receiver faults, it is necessary to get the accurate fault parameters in the rift zones. Some historical earthquakes have been studied using the field data, teleseismic data and InSAR observations, but results are in not agreement with each other. In this study, we revaluated the geometrical parameters of seismogenic faults occurred in the rift zones using some high-quality coseismic InSAR observations and teleseismic body-wave data. Finally, we will evaluate the seismic hazard in the rift zones according to the value of the estimated CFS and aftershock distribution.

  1. Structure and evolution of the northern Oman margin: gravity and seismic constraints over the Zagros-Makran-Oman collision zone

    Science.gov (United States)

    Ravaut, P.; Bayer, R.; Hassani, R.; Rousset, D.; Yahya'ey, A. Al

    1997-09-01

    The obduction process in Oman during Late Cretaceous time, and continental-to-oceanic subduction along the Zagros-Makran region during the Tertiary are consequences of the Arabian-Eurasian collision, resulting in construction of complex structures composed of the Oman ophiolite belt, the Zagros continental mountain belt and the Makran subduction zone with its associated accretionary wedge. In this paper, we jointly interpret Bouguer anomaly and available petroleum seismic profiles in terms of crustal structures. We show that the gravity anomaly in northern Oman is characterized by a high-amplitude negative-positive couple. The negative anomaly is coincident with Late Cretaceous (Fiqa) and Tertiary (Pabdeh) foreland basins and with the Zagros-Oman mountain belts, whereas the positive anomaly is correlated to the ophiolite massifs. The Bouguer anomaly map indicates the presence of a post-Late Cretaceous sedimentary basin, the Sohar basin, centred north of the Batinah plain. We interpret the negative/positive couple in terms of loading of the elastic Arabian lithosphere. We estimate the different Cretaceous-to-Recent loads, including topography, ophiolite nappes, sedimentary fill and the accretionary prism of the Makran trench. A new method, using Mindlin's elastic plate theory, is proposed to model the 2D deflection of the heterogeneous elastic Arabian plate, taking into account boundary conditions at the ends of the subducted plate. We show that remnant ophiolites are isolated from Tethyan oceanic lithosphere in the Gulf of Oman by a continental basement ridge, a NW prolongation of the Saih-Hatat window. Loading the northward-limited ophiolite blocks explains the deflection of the Fiqa foredeep basin. West of the Musandam Peninsula, the Tertiary Pabdeh foredeep is probably related to the emplacement of a 8-km-thick tectonic prism located on the Musandam Peninsula and in the Strait of Hormuz. Final 2D density models along profiles through the Oman mountain belt and

  2. Investigation of Fault Zones In The Penninic Gneiss Complex of The Swiss Central Alps Using Tomograhic Inversion of The Seismic Wavefield Along Tunnels

    Science.gov (United States)

    Giese, R.; Klose, C.; Otto, P.; Selke, C.; Borm, G.

    Underground seismic investigations have been carried out since March 2000 in the Faido adit of the Gotthard Base Tunnel (Switzerland) and the Piora exploration adit. Both adits cut metamorphic rock formations of the Leventina and Lucomagno Gneiss Complexes. The seismic measurements in the Faido Adit were carried out every 200 m during the excavation work with the Integrated Seismic Imaging System (ISIS) developed by the GeoForschungsZentrum Potsdam in cooperation with Amberg Measuring Technique, Switzerland. This system provides high resolution seismic images via an array of stan- dard anchor rods containing 3D-geophones which can be installed routinely during the excavation process. The seismic source is a repetitive pneumatic impact hammer. For each measurement in the Faido adit, seismic energy was transmitted from 30 to 50 source points distributed along the tunnel wall at intervals of 1.0 to 1.5 m. In the Piora exploration adit a 2D grid of 441 source points distributed along a distance of 147 tunnel meters were measured. In both adits the shots were recorded by arrays of 8 to 16 three - component geophone anchor rods glued into 2 m deep boreholes at intervals of 9 m - 10 m. The total length of all profiles was about 850 m. Seismic sections show first P-wave energy at frequencies up to 2 kHz and S-wave energy up to 1.3 kHz. Reflection energy was observed from distances of up to 350 m for P-waves and 200 m for S-waves. The dominant frequencies of reflective energy were found between 600 and 800 Hz for P-waves and between 200 and 400 Hz for S-waves. The corresponding wave lengths were 8 to 10 m. We used the first arrival times of P- and S- waves to calculate tomographic inversions. The 2D-velocity models for P- and S-waves in the Faido adit revealed a near field of 2 to 3 m from the tunnel surface which is characterized by strong velocity variations: 3000 to 5700 m/s for P-wave velocity (Vp) and 2000 to 3000 m/s for S-wave velocity (Vs). High velocity zones

  3. Evidence for a low permeability fluid trap in the Nový Kostel Seismic Zone, Czech Republic, using double-difference tomography

    Science.gov (United States)

    Alexandrakis, C.; Calo, M.; Vavrycuk, V.

    2012-12-01

    The West Bohemia/Vogtland region is the border area between the Czech Republic and Germany known for frequent occurrences of earthquake swarms. The most prominent earthquake swarms occurred recently in 1985/86, 1997, 2000 (Fischer and Horálek, 2003) and 2008 (Fischer et al., 2010). They comprised thousands of microearthquakes, their duration was between 2 weeks to 2 months, and the activity focused typically at depths ranging from 7 to 12 km. The seismic activity is concentrated mostly at the same epicentral area, called the Nový Kostel Zone. This zone is located on the edge of the Cheb Basin, Eger Rift, and at the junction of the Mariánské-Lázně Fault with the Počátky-Plesná Shear Zone. Numerous gas vents and mineral springs within and around the Cheb Basin indicate that uprising magmatic fluids may act as a swarm trigger. In this study, we apply double-difference tomography to investigate the structure within and around the Nový Kostel focal zone. We use data from the 2008 earthquake swarm, as it has been extensively analyzed, and focal mechanisms, principal faults, tectonic stress, source migration and other basic characteristics are known. We selected about 500 microearthquakes recorded at 22 local seismic stations of the West Bohemia Network (WEBNET). The events were inverted for the 3-D seismic structure using the TomoDD code (Zhang and Thurber, 2003) and post-processed using the Weighted Average Model method (Calò et al., 2011). The application of double-difference tomography is advantageous for this setting as swarm foci are closely spaced and form a dense cluster. The geometry of the focal zone and the WEBNET network configuration offer good raypath coverage in all directions. Applying double-difference tomography we produce and interpret 3-D models of the P and S velocities. In this work, we interpret 3-D models of the P velocity and P-to-S ratio in and around the focal zone. The P-to-S model was obtained by calculating directly the ratio

  4. High-resolution seismic survey for the characterization of planned PIER-ICDP fluid-monitoring sites in the Eger Rift zone

    Science.gov (United States)

    Simon, H.; Buske, S.

    2017-12-01

    The Eger Rift zone (Czech Republic) is a intra-continental non-volcanic region and is characterized by outstanding geodynamic activities, which result in earthquake swarms and significant CO2 emanations. Because fluid-induced stress can trigger earthquake swarms, both natural phenomena are probably related to each other. The epicentres of the earthquake swarms cluster at the northern edge of the Cheb Basin. Although the location of the cluster coincides with the major Mariánské-Lázně Fault Zone (MLFZ) the strike of the focal plane indicates another fault zone, the N-S trending Počátky-Plesná Zone (PPZ). Isotopic analysis of the CO2-rich fluids revealed a significant portion of upper mantle derived components, hence a magmatic fluid source in the upper mantle was postulated. Because of these phenomena, the Eger Rift area is a unique site for interdisciplinary drilling programs to study the fluid-earthquake interaction. The ICDP project PIER (Probing of Intra-continental magmatic activity: drilling the Eger Rift) will set up an observatory, consisting of five monitoring boreholes. In preparation for the drilling, the goal of the seismic survey is the characterization of the projected fluid-monitoring drill site at the CO2 degassing mofette field near Hartoušov. This will be achieved by a 6 km long profile with dense source and receiver spacing. The W-E trending profile will cross the proposed drill site and the surface traces of MLFZ and PPZ. The outcome of the seismic survey will be a high-resolution structural image of potential reflectors related to these fault zones. This will be achieved by the application of advanced pre-stack depth migration methods and a detailed P-wave velocity distribution of the area obtained from first arrival tomography. During interpretation of the seismic data, a geoelectrical resistivity model, acquired along the same profile line, will provide important constraints, especially with respect to fluid pathways.

  5. Design of turbine foundations in seismic zones. Earthquake protection strategies; Planung von Turbinenfundamenten in Erdbebengebieten. Strategien zum Erdbebenschutz

    Energy Technology Data Exchange (ETDEWEB)

    Basu, Ashish Kumar [GERB Vibration Control Systems, Noida (India); Nawrotzki, Peter [GERB Schwingungsisolierungen GmbH und Co. KG, Berlin (Germany); Siepe, Daniel [GERB Engineering GmbH, Essen (Germany)

    2011-04-15

    This contribution reveals basic principles of elastic support systems and applications on power plant equipment and buildings in medium and high seismic areas. Spring-damper combinations with special stiffness properties are used to reduce seismic acceleration levels of turbine components and other safety or non-safety related structures. For turbine buildings, the integration of the turbine substructure into the machine building can additionally reduce the relative displacement between both the structures as well as the stress levels in all structural members. (orig.)

  6. Determination of Seismic Safety Zones during the Surface Mining Operation Development in the Case of the “Buvač” Open Pit

    Directory of Open Access Journals (Sweden)

    Vladimir Malbasic

    2018-02-01

    Full Text Available Determination of the blasting safety area is a very important step in the process of drilling and blasting works, and the preparation of solid rock materials for loading. Through monitoring and analysis of the negative seismic effects to the objects and infrastructures around and at the mine area, we were able to adapt the drilling and blasting parameters and organization of drilling and blasting operation according to the mining progress so that the affected infrastructures could be protected. This paper analyses the safety distances and model safety zones of drilling and blasting for the period 2013–2018 at the open pit at “Buvač”, Omarska. This mathematical calculation procedure can be used during the whole life of the mine. By monitoring of the blasting seismic influence in first years of the mine's work, as well as by using recorded vibration velocities, mathematical dependence of the important parameters can be defined. Additionally, the level and laws of distribution and intensity of the seismic activity can be defined. On one hand, those are known quantities of the explosive and the distances between blasting location and endangered objects. On the other hand, those are coefficients of the manner of blasting and the environment where blasting is done, K, as well as the coefficient of the weakening of seismic waves as they spread, n. With the usage of the allowed vibration velocities, based on certain safety criteria and mathematical formulas of laws of spreading and intensity of seismic influence for a concrete case, it is possible to calculate explosive quantities and distances, with numerically-defined values of parameter K and n. Minimum distances are calculated based on defined or projected explosive quantities. Additionally, we calculate the maximum allowed explosive quantities based on known distances which can be used based on projected drilling-blasting parameters. For the purpose of the planning of drilling and blasting

  7. Geomagnetic signal induced by the M5.7 earthquake occurred on September 24-th, 2016, in the seismic active Vrancea zone, Romania

    Science.gov (United States)

    Stanica, Dumitru; Armand Stanica, Dragos

    2017-04-01

    In this paper, we used the geomagnetic time series collected in real time by the electromagnetic monitoring system, placed at the Geomagnetic Observatory Provita de Sus, to emphasize possible relationships between the pre-seismic anomalous behavior of the normalized function Bzn and M5.7 earthquake occurrence in Vrancea seismic active zone, on September 24, 2016. It has already been demonstrated (Stanica and Stanica, 2012, Stanica et al., 2015) that for a 2D geoelectric structure, in pre-seismic conditions, the normalized function Bzn has significant changes in magnitudes due to the electrical conductivity changes, possibly associated with the earthquake-induced rupture-processes and high-pressure fluid flow through the faulting systems developed inside the Vrancea seismogenic volume and along the Carpathian electrical conductivity anomaly. In this circumstances, the daily mean distributions of the Bzn = Bz/Bperp (where Bz is vertical component of the geomagnetic field; Bperp is geomagnetic component perpendicular to the geoelectric strike) and its standard deviation (SD) are performed in the ULF frequency range 0.001Hz to 0.0083Hz by using both the FFT band-pass filter analysis and statistical analysis based on a standardized random variable equation. After analyzing the pre-seismic anomalous intervals, a pre-seismic geomagnetic signal greater than 5 SD was identified on September 22, 2016, what means a lead time of 2 days before the M5.7 earthquake occurred on September 24, emphasized in real time on the web site (www.geodin.ro). The final conclusion is that the proposed geomagnetic methodology might be used to provide suitable information for the extreme seismic hazard assessment and risk mitigation. References: Dumitru Stanica and Dragos Armand Stanica, Earthquakes precursors, in "Earthquake Research and Analysis-Statistical Studies, Observations and Planning" Book 5, edited by: Dr. Sebastiano D'Amico, ISBN 978-953-51-0134-5, InTech open access publisher

  8. Structural analysis of S-wave seismics around an urban sinkhole: evidence of enhanced dissolution in a strike-slip fault zone

    Directory of Open Access Journals (Sweden)

    S. H. Wadas

    2017-12-01

    Full Text Available In November 2010, a large sinkhole opened up in the urban area of Schmalkalden, Germany. To determine the key factors which benefited the development of this collapse structure and therefore the dissolution, we carried out several shear-wave reflection-seismic profiles around the sinkhole. In the seismic sections we see evidence of the Mesozoic tectonic movement in the form of a NW–SE striking, dextral strike-slip fault, known as the Heßleser Fault, which faulted and fractured the subsurface below the town. The strike-slip faulting created a zone of small blocks ( < 100 m in size, around which steep-dipping normal faults, reverse faults and a dense fracture network serve as fluid pathways for the artesian-confined groundwater. The faults also acted as barriers for horizontal groundwater flow perpendicular to the fault planes. Instead groundwater flows along the faults which serve as conduits and forms cavities in the Permian deposits below ca. 60 m depth. Mass movements and the resulting cavities lead to the formation of sinkholes and dissolution-induced depressions. Since the processes are still ongoing, the occurrence of a new sinkhole cannot be ruled out. This case study demonstrates how S-wave seismics can characterize a sinkhole and, together with geological information, can be used to study the processes that result in sinkhole formation, such as a near-surface fault zone located in soluble rocks. The more complex the fault geometry and interaction between faults, the more prone an area is to sinkhole occurrence.

  9. Active crustal deformation of the El Salvador Fault Zone by integrating geodetic, seismological and geological data: application in seismic hazard assessment

    Science.gov (United States)

    Staller, A.; Benito, B.; Martínez-Díaz, J.; Hernández, D.; Hernández-Rey, R.

    2013-05-01

    El Salvador, Central America, is part of the Chortis block in the northwestern boundary of the Caribbean plate. This block is interacting with a diffuse triple junction point with the Cocos and North American plates. Among the structures that cut the Miocene to Pleistocene volcanic deposits stands out the El Salvador Fault Zone (ESFZ): It is oriented in N90-100E direction, and it is composed of several structural segments that deform Quaternary deposits with right-lateral and oblique slip motions. The ESFZ is seismically active and capable of producing earthquakes such as the February 13, 2001 with Mw 6.6 (Martínez-Díaz et al., 2004), that seriously affected the population, leaving many casualties. This structure plays an important role in the tectonics of the Chortis block, since its motion is directly related to the drift of the Caribbean plate to the east and not with the partitioning of the deformation of the Cocos subduction (here not coupled) (Álvarez-Gómez et al., 2008). Together with the volcanic arc of El Salvador, this zone constitutes a weakness area that allows the motion of forearc block toward the NW. The geometry and the degree of activity of the ESFZ are not studied enough. However their knowledge is essential to understand the seismic hazard associated to this important seismogenic structure. For this reason, since 2007 a GPS dense network was established along the ESFZ (ZFESNet) in order to obtain GPS velocity measurements which are later used to explain the nature of strain accumulation on major faults along the ESFZ. The current work aims at understanding active crustal deformation of the ESFZ through kinematic model. The results provide significant information to be included in a new estimation of seismic hazard taking into account the major structures in ESFZ.

  10. Deformation and seismic anisotropy of the subcontinental lithospheric mantle in NE Spain: EBSD data on xenoliths from the Catalan Volcanic Zone

    Science.gov (United States)

    Fernández-Roig, Mercè; Galán, Gumer; Mariani, Elisabetta

    2017-02-01

    Mantle xenoliths in Neogene-Quaternary basaltic rocks related to the European Cenozoic Rift System serve to assess the evolution of the subcontinental lithospheric mantle beneath the Catalan Volcanic Zone in NE Spain. Crystallographic preferred orientations, major element composition of minerals, and temperature and pressure estimates have been used to this end. The mantle consists of spinel lherzolites, harzburgites and subordinate websterites. Protogranular microstructures are found in all peridotites and websterites, but lherzolites also display finer-grained porphyroclastic and equigranular microstructures. The dominant olivine deformation fabric is [010] fiber, but subordinate orthorhombic and [100]-fiber types are also present, especially in porphyroclastic and equigranular lherzolites. The fabric strength (J index = 10.12-1.91), equilibrium temperature and pressure are higher in xenoliths with [010]-fiber fabric and decrease in those with orthorhombic and [100]-fiber type. Incoherence between olivine and pyroxene deformation fabric is mostly found in porphyroclastic and equigranular lherzolites. Seismic anisotropy, estimated from the crystal preferred orientations, also decreases (AVp = 10.2-2.60%; AVs max = 7.95-2.19%) in porphyroclastic and equigranular lherzolites. The olivine [010]-fiber fabric points to deformation by simple shear or transpression which is likely to have occured during the development of late-Hercynian strike-slip shear zones, and to subsequent annealing during late Hercynian decompression, Permian and Cretaceous rifting. Also, it cannot be excluded that the percolation of mafic magmas during these extensional events provoked the refertilization of the lithospheric mantle. However, no clear relationship has been observed between fabric strength and mineral mode and composition. Later transtensional deformation during late Alpine orogenesis, at higher stress and decreasing temperature and pressure, transformed the earlier fabric into

  11. Fluid activity within the North Anatolian Fault Zone according to 3D marine seismic data on the Sea of Marmara Western High

    Science.gov (United States)

    Grall, C.; Henry, P.; Thomas, Y.; Marsset, B.; Westbrook, G.; Saritas, H.; Géli, L.; Ruffine, L.; Dupré, S.; Scalabrin, C.; Augustin, J. M.; Cifçi, G.; Zitter, T.

    2012-04-01

    Along the northern branch of the North Anatolian Fault Zone (NAFZ) within the Sea of Marmara, numerous gas seeps occur. A large part of the gas origin is biogenic but on the Western High, gas bubbles and gas hydrate with a thermogenic signature have been sampled. The expulsion of deep fluids opened new perspective about the permeability, the mechanical properties and the monitoring of the NAFZ. Consequently, the Western High was selected for the deployment of a 3D seismic acquisition layout during the MARMESONET cruise (2009). Thirty-three km2 of high resolution seismic data (with a frequency content of 50-180 Hz) have been collected within the shear band of the fault. The SIMRAD EM-302 was also operated to detect acoustic anomalies related to the presence of gas bubbles in the water column. Within the upper sedimentary cover (seismic penetration ranges from 100 to 500 m bsf), high seismic amplitude variations of the reflectors allow to identify gas traps and gas pathways. Local high amplitude of negative polarity, such as flat spots and bright spots, are observed. Amplitude anomalies are located above and within anticlines and along normal faults. They often correlate with seafloor manifestations of fluid outflow and gas plumes in the water column. This suggests that gas migrates from depth towards the seafloor along normal faults and permeable strata, and part of it is trapped in anticlines. North of the NAF, seabed mounds, corresponding to active hydrocarbon gas seeps, are aligned along a NE-SW direction. They are linked in depth to buried mud volcanoes with an episodic activity. The last mud eruption activity apparently just before or during the Red-H1 horizon deposition which is a prominent reflector of high amplitude and negative polarity occurring all over the Sea of Marmara. It has been interpreted as a stratigraphic horizon, corresponding to slow sedimentation and high sea-level interglacial period.

  12. Seismically-induced soil amplification at the DOE Paducah Gaseous Diffusion Plant site

    International Nuclear Information System (INIS)

    Sykora, D.W.; Haynes, M.E.

    1991-01-01

    A site-specific earthquake site response (soil amplification) study is being conducted for the Department of Energy (DOE), Paducah Gaseous Diffusion Plant (PGDP). This study is pursuant to an upgraded Final Safety Analysis Report in accordance with requirements specified by DOE. The seismic hazard at PGDP is dominated by the New Madrid Seismic Zone. Site-specific synthetic earthquake records developed by others were applied independently to four soil columns with heights above baserock of about 325 ft. The results for the 1000-year earthquake event indicate that the site period is between 1.0 and 1.5 sec. Incident shear waves are amplified at periods of motion greater than 0.15 sec. The peak free-field horizontal acceleration, occurring at very low periods, is 0.28 g. 13 refs., 13 figs

  13. Seismically-induced soil amplification at the DOE Paducah Gaseous Diffusion Plant Site

    International Nuclear Information System (INIS)

    Sykora, D.W.; Hynes, M.E.; Brock, W.R.; Hunt, R.J.; Shaffer, K.E.

    1991-01-01

    A site-specific earthquake site response (soil amplification) study is being conducted for the Department of Energy (DOE), Paducah Gaseous Diffusion Plant (PGDP). This study is pursuant to an upgraded Final Safety Analysis Report in accordance with requirements specified by DOE. The seismic hazard at PGDP is dominated by the New Madrid Seismic Zone. Site-specific synthetic earthquake records developed by others were applied independently to four soil columns with heights above baserock of about 325 ft. The results for the 1000-year earthquake event indicate that the site period is between 1.0 and 1.5 sec. Incident shear waves are strongly amplified at periods of motion greater than 0.3 sec. The peak free-field horizontal acceleration, occurring at very low periods, is 0.28 g

  14. Fault zone architecture of the San Jacinto fault zone in Horse Canyon, southern California: A model for focused post-seismic fluid flow and heat transfer in the shallow crust

    Science.gov (United States)

    Morton, Nissa; Girty, Gary H.; Rockwell, Thomas K.

    2012-05-01

    We report results of a new study of the architecture of the San Jacinto fault zone in Horse Canyon, California, where stream incision has exposed a nearly continuous outcrop of the fault zone at ~ 0.4 km depth. The fault zone at this location consists of a fault core, transition zone, damage zone, and tonalitic wall rocks. We collected and analyzed samples for their bulk and grain density, geochemical data, clay mineralogy, and textural and modal mineralogy. Progressive deformation within the fault zone is characterized by mode I cracking, subsequent shearing of already fractured rock, and cataclastic flow. Grain comminution advances towards the strongly indurated cataclasite fault core. Damage progression towards the core is accompanied by a decrease in bulk and grain density, and an increase in porosity and dilational volumetric strain. Palygorskite and mixed-layer illite/smectite clay minerals are present in the damage and transition zones and are the result of hydrolysis reactions. The estimated percentage of illite in illite/smectite increases towards the fault core where the illite/smectite to illite conversion is complete, suggesting elevated temperatures that may have reached 150 °C. Chemical alteration and elemental mass changes are observed throughout the fault zone and are most pronounced in the fault core. We conclude that the observed chemical and mineralogical changes can only be produced by the interaction of fractured wall rocks and chemically active fluids that are mobilized through the fault zone by thermo-pressurization during and after seismic events. Based on the high element mobility and absence of illite/smectite in the fault core, we expect that the greatest water/rock ratios occur within the fault core. These results indicate that hot pore fluids circulate upwards through the fractured fault core and into the surrounding damage zone. Though difficult to constrain, we speculate that the site studied during this investigation may represent

  15. Model of the seismic velocity distribution in the upper lithosphere of the Vrancea seismogenic zone and within the adjacent areas

    International Nuclear Information System (INIS)

    Raileanu, Victor; Bala, Andrei

    2002-01-01

    The task of this project is to perform a detailed seismic velocity model of the P waves in the crust and upper mantle crossed by the VRANCEA 2001 seismic line and to interpret it in structural terms. The velocity model aims to contribute to a new geodynamical model of the Eastern Carpathians evolution and to a better understanding of the causes of the Vrancea earthquakes. It is performed in cooperation with the University of Karlsruhe, Germany, and University of Bucharest. The Project will be completed in 5 working stages. Vrancea 2001 is the name of the seismic line recorded with about 780 seismic instruments deployed over more then 600 km length from eastern part of Romania (east Tulcea) through Vrancea area to Aiud and south Oradea. 10 big shots with charges from 300 kg to 1500 kg dynamite were detonated along seismic line. Field data quality is from good to very good and it provides information down to the upper mantle levels. Processing of data has been performed in the first stage of present project and it consisted in merging of all individual field records in seismograms for each shotpoint. Almost 800 individual records for each out of the 10 shots were merged in 10 seismograms with about 800 channels. A seismogram of shot point S (25 km NE of Ramnicu Sarat) is given. It is visible a high energy generated by shotpoint S. Pn wave can be traced until the western end of seismic line, about 25 km from source. In the second stage of project an interpretation of seismic data is achieved for the first 5 seismograms from the eastern half of seismic line, from Tulcea to Ramnicu Sarat. It is used a forward modeling procedure. 5 unidimensional (1D) velocity-depth function models are obtained. P wave velocity-depth function models for shotpoints from O to T are presented. Velocity-depth information is extended down to 40 km for shot R and 80 km for shot S. It should noticed the unusually high velocities at the shallow levels for Dobrogea area (O and P shots) and the

  16. Near surface structure of the North Anatolian Fault Zone near 30°E from Rayleigh and Love wave tomography using ambient seismic noise.

    Science.gov (United States)

    Taylor, G.; Rost, S.; Houseman, G. A.; Hillers, G.

    2017-12-01

    By utilising short period surface waves present in the noise field, we can construct images of shallow structure in the Earth's upper crust: a depth-range that is usually poorly resolved in earthquake tomography. Here, we use data from a dense seismic array (Dense Array for Northern Anatolia - DANA) deployed across the North Anatolian Fault Zone (NAFZ) in the source region of the 1999 magnitude 7.6 Izmit earthquake in western Turkey. The NAFZ is a major strike-slip system that extends 1200 km across northern Turkey and continues to pose a high level of seismic hazard, in particular to the mega-city of Istanbul. We obtain maps of group velocity variation using surface wave tomography applied to short period (1- 6 s) Rayleigh and Love waves to construct high-resolution images of SV and SH-wave velocity in the upper 5 km of a 70 km x 35 km region centred on the eastern end of the fault segment that ruptured in the 1999 Izmit earthquake. The average Rayleigh wave group velocities in the region vary between 1.8 km/s at 1.5 s period, to 2.2 km/s at 6 s period. The NAFZ bifurcates into northern and southern strands in this region; both are active but only the northern strand ruptured in the 1999 event. The signatures of both the northern and southern branches of the NAFZ are clearly associated with strong gradients in seismic velocity that also denote the boundaries of major tectonic units. This observation implies that the fault zone exploits the pre-existing structure of the Intra-Pontide suture zone. To the north of the NAFZ, we observe low S-wave velocities ( 2.0 km/s) associated with the unconsolidated sediments of the Adapazari basin, and blocks of weathered terrigenous clastic sediments. To the south of the northern branch of the NAFZ in the Armutlu block, we detect higher velocities ( 2.9 km/s) associated with a shallow crystalline basement, in particular a block of metamorphosed schists and marbles that bound the northern branch of the NAFZ.

  17. Seismicity, groundwater level variations and Earth tides in the Hronov-Poříčí Fault Zone, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Kolínský, Petr; Valenta, Jan; Gaždová, Renata

    2012-01-01

    Roč. 9, č. 2 (2012), s. 191-209 ISSN 1214-9705 R&D Projects: GA ČR GA205/09/1244 Institutional research plan: CEZ:AV0Z30460519 Keywords : Eastern Bohemian Massif * groundwater level * seismic ity Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.530, year: 2011 http://www.irsm.cas.cz/materialy/acta_content/2012_02/9_Kolinsky.pdf

  18. Crustal seismicity associated to rpid surface uplift at Laguna del Maule Volcanic Complex, Southern Volcanic Zone of the Andes

    Science.gov (United States)

    Cardona, Carlos; Tassara, Andrés; Gil-Cruz, Fernando; Lara, Luis; Morales, Sergio; Kohler, Paulina; Franco, Luis

    2018-03-01

    Laguna del Maule Volcanic Complex (LMVC, Southern Andes of Chile) has been experiencing large rates (ca. 30 cm/yr) of surface uplift as detected since 2008 by satellite geodetic measurements. Previous works have modeled the source of this deformation as an inflating rectangular sub-horizontal sill underlying LMVC at 5 km depth, which is supposedly related to an active process of magmatic replenishment of a shallow silicic reservoir. However little is known about the tectonic context on which this activity is taking place, particularly its relation with crustal seismicity that could help understanding and monitoring the current deformation process. Here we present the first detailed characterization of the seismic activity taking place at LMVC and integrate it with structural data acquired in the field in order to illuminate the possible connection between the ongoing process of surface uplift and the activation of crustal faults. Our main finding is the recognition of repetitive volcano-tectonic (VT) seismic swarms that occur periodically between 2011 and 2014 near the SW corner of the sill modeled by InSAR studies. A cross-correlation analysis of the waveforms recorded for these VT events allows identifying three different seismic families. Families F1 and F3 share some common features in the stacked waveform and its locations, which markedly differ from those of family F2. Swarms belonging to this later family are more energetic and its energy was increasing since 2011 to a peak in January 2013, which coincide with maximum vertical velocities detected by local GPS stations. This points to a common process relating both phenomena. The location of VT seismic swarms roughly coincides with the intersection of a NE-SW lineament with a WNW-ESE lineament. The former shows clear field evidences of dextral strike-slip that are fully consistent with one nodal plane of focal mechanism for well-recorded F2 events. The conjugate nodal plane of these focal mechanisms could

  19. Madrid, ciudad de la ciencia

    Directory of Open Access Journals (Sweden)

    Emilio Parrilla Gorbea

    2012-12-01

    Full Text Available La ciudad de Madrid ha sido y es uno de los principales polos de actividad científico-tecnológica de España. Concentra una parte fundamental de las instituciones públicas de investigación y desarrollo. Madrid ha sido un lugar de producción y localización científico-tecnológica de primer nivel nacional, desde los comienzos de la Ilustración en la época de Carlos III, posteriormente en el siglos XIX, en la época del "Cajalismo" de principios del XX, con la JAE (Junta de Ampliación de Estudios, con el CSIC y con el Ministerio de Ciencia e Innovación y Madrid Network. Ha existido una secuencia espacial y temporal en la localización de sedes de instituciones científico-técnicas en la ciudad a lo largo del tiempo. Con este trabajo de investigación se analiza la formación de este sistema y sus características básicas, se evalúa si ha formado un conjunto de áreas significativas en la ciudad que permitan hablar de un proyecto o conjunto de proyectos que han formado el sistema científico-técnico de Madrid. Finalmente se analiza cómo es en la actualidad este sistema y si está concluido o si por el contrario está pendiente de terminar y desarrollar en estos momentos a principios del siglo XXI. Abstract: The city of Madrid has been, and now is too, one of the most important scientific and technical activity poles of Spain. It concentrates a great part of the public Research and Development institutions. Madrid has been a first level place for location and national scientific and technical production, since the beginnings of the Age of Enlightenment in the Carlos III epoch, later in the XIX century, in the "Cajalismo" period at first of the XX century, With JAE "Junta de Ampliación de Estudios", with CSIC and with the "Ministerio de Ciencia e Innovación" and "Madrid Network". There has been a time and spatial sequence in location of the scientific and technical headquarters and institutions in the city along time. In this

  20. A Bimodal Hybrid Model for Time-Dependent Probabilistic Seismic Hazard Analysis

    Science.gov (United States)

    Yaghmaei-Sabegh, Saman; Shoaeifar, Nasser; Shoaeifar, Parva

    2018-03-01

    The evaluation of evidence provided by geological studies and historical catalogs indicates that in some seismic regions and faults, multiple large earthquakes occur in cluster. Then, the occurrences of large earthquakes confront with quiescence and only the small-to-moderate earthquakes take place. Clustering of large earthquakes is the most distinguishable departure from the assumption of constant hazard of random occurrence of earthquakes in conventional seismic hazard analysis. In the present study, a time-dependent recurrence model is proposed to consider a series of large earthquakes that occurs in clusters. The model is flexible enough to better reflect the quasi-periodic behavior of large earthquakes with long-term clustering, which can be used in time-dependent probabilistic seismic hazard analysis with engineering purposes. In this model, the time-dependent hazard results are estimated by a hazard function which comprises three parts. A decreasing hazard of last large earthquake cluster and an increasing hazard of the next large earthquake cluster, along with a constant hazard of random occurrence of small-to-moderate earthquakes. In the final part of the paper, the time-dependent seismic hazard of the New Madrid Seismic Zone at different time intervals has been calculated for illustrative purpose.

  1. Allergenic pollen pollinosis in Madrid.

    Science.gov (United States)

    Subiza, J; Jerez, M; Jiménez, J A; Narganes, M J; Cabrera, M; Varela, S; Subiza, E

    1995-07-01

    A 15-year pollen count was performed in the atmosphere of Madrid, Spain, to determine the months in which the highest concentrations of allergenic pollens occur. Pollen counts were done with a Burkard spore trap (Burkard Manufacturing, Rickmansworth, Herst., U.K.). The results were subsequently compared with results of skin tests in patients with pollinosis born and living in and around Madrid. The highest airborne presence (percent of total yearly pollen counts, mean of counts from 1979 to 1993) was for Quercus spp. (17%); followed by Platanus spp. (15%), Poaceae (15%), Cupressaceae (11%), Olea spp. (9%), Pinus spp. (7%), Populus spp. (4%), and Plantago spp. (4%). The most predominant pollens from January to April are tree pollens (Cupressaceae, Alnus, Fraxinus, Ulmus, Populus, Platanus, and Morus), although these are also abudant in May and June (Quercus, Olea, and Pinus spp.). The grass pollination period shows a double curve: the first peak occurs from February to April (8% of yearly grasses), and the second peak occurs from May to July (90% of yearly grasses). Among allergenically significant weeds, the most notable is Plantago; in contrast, Rumex, Urticaceae, Cheno-Amaranthaceae, and Artemisia spp. have very low concentrations (arizonica (20%). The population of Madrid is exposed to high concentrations of allergenic pollen from February to July, although the most intense period is from May to June. Grass pollens are the most important cause of pollinosis in this area.

  2. Casa Santoja, en Somosaguas, Madrid

    Directory of Open Access Journals (Sweden)

    Higueras, Fernando

    1968-04-01

    Full Text Available This is a single family house, of powerful texture and severe outline. It is sited on open ground at Somosaguas, and enjoys a fine view of the Madrid Sierra. The city of Madrid can be seen in the distance, and also the imposing background of the lofty mountains in the opposite direction. Granite stone and Oregon pinewood are almost the only materials utilised. Their quality, natural aspect and the audacious design adopted throughout are outstanding features of this project.Esta vivienda unifamiliar, de poderosa textura y severas líneas, campea sobre ima parcela de Somosaguas, mirando abiertamente, sin obstáculos, hacia el magnífico panorama serrano de Madrid. La capital se extiende ante la vista, con su belleza indudable, por una parte, y la altiva montaña pone su fondo imponente, por las otras. La piedra granítica y la madera de pino de Oregón son casi los únicos materiales empleados. Su calidad, su color natural y las formas atrevidas de la construcción toda, son las notas fundamentales que la hacen destacar de manera notable.

  3. Earthquake clustering in modern seismicity and its relationship with strong historical earthquakes around Beijing, China

    Science.gov (United States)

    Wang, Jian; Main, Ian G.; Musson, Roger M. W.

    2017-11-01

    Beijing, China's capital city, is located in a typical intraplate seismic belt, with relatively high-quality instrumental catalogue data available since 1970. The Chinese historical earthquake catalogue contains six strong historical earthquakes of Ms ≥ 6 around Beijing, the earliest in 294 AD. This poses a significant potential hazard to one of the most densely populated and economically active parts of China. In some intraplate areas, persistent clusters of events associated with historical events can occur over centuries, for example, the ongoing sequence in the New Madrid zone of the eastern US. Here we will examine the evidence for such persistent clusters around Beijing. We introduce a metric known as the `seismic density index' that quantifies the degree of clustering of seismic energy release. For a given map location, this multi-dimensional index depends on the number of events, their magnitudes, and the distances to the locations of the surrounding population of earthquakes. We apply the index to modern instrumental catalogue data between 1970 and 2014, and identify six clear candidate zones. We then compare these locations to earthquake epicentre and seismic intensity data for the six largest historical earthquakes. Each candidate zone contains one of the six historical events, and the location of peak intensity is within 5 km or so of the reported epicentre in five of these cases. In one case—the great Ms 8 earthquake of 1679—the peak is closer to the area of strongest shaking (Intensity XI or more) than the reported epicentre. The present-day event rates are similar to those predicted by the modified Omori law but there is no evidence of ongoing decay in event rates. Accordingly, the index is more likely to be picking out the location of persistent weaknesses in the lithosphere. Our results imply zones of high seismic density index could be used in principle to indicate the location of unrecorded historical of palaeoseismic events, in China and

  4. Instituto de Psicoterapia, Madrid

    Directory of Open Access Journals (Sweden)

    Schoebel Ungria, Willi

    1963-06-01

    Full Text Available This building is situated within the «Peña Retama» estate, in the midst of an extensive garden, where it is planned to build in the immediate future a swimming pool and a pelota court. Basically, this Institute provides facilities for leading a form of life that is both peaceful and busy. With this object in view training courses in languages, painting, and amateur film making are organised. There is a book and recordings library. Furthermore, the close relationship between the doctor and the patient is not neglected, and a very discreet surveillance is maintained over the patients. The general distribution of the Institute involves three main zones: one for men, one for women and a relaxation zone. Each of them has individual apartments and small drawing and living rooms, which can be easily transformed into dining rooms. The wing of the building devoted to sleeping treatment is more isolated and independent and includes ample terraces suitable for summer and winter use. The interior decoration has been carefully planned, aiming to make it both intimate and pleasant. Colour schemes are so-called «tranquil», and avoid vivid, exciting and intense colour patterns. The outside of the building harmonises with the background of mountain scenery, and as a whole, the project is eminently functional and efficient in its detailed design.Se alza sobre la finca «Peña Retama», dentro de un extenso espacio ajardinado donde se prevé, en un futuro próximo, la construcción de una piscina y un frontón. Fundamentalmente, se trata de un Centro con posibilidades para hacer una vida, a la vez tranquila y ocupada; con esta finalidad se organizan clases de idiomas, pintura, sesiones de cine-club, y se dispone de una biblioteca-discoteca; pero sin descuidar la necesaria relación y contacto muy personal de enfermo y médico, y una vigilancia discretísima sobre aquél. En su distribución general se acusan tres zonas: hombres, mujeres y zona de reposo, que

  5. Tourism sector preparedness in zones with a high seismic risk: Case study of the Capital Region of Japan

    Science.gov (United States)

    Lihui, W.; Wang, D.

    2017-12-01

    Japan is a country highly vulnerable to natural disasters, especially earthquakes. Tourism, as a strategic industry in Japan, is especially vulnerable to destructive earthquake disasters owing to the characteristics of vulnerability, sensitivity and substitutability. Here we aim to provide theoretical understanding of the perception and responses of tourism managers towards damaging disasters in tourism destinations with high seismic risks. We conducted surveys among the mangers of tourism businesses in the capital area of Japan in 2014 and applied structural equation modeling techniques to empirically test the proposed model with four latent variables, which are risk perception, threat knowledge, disaster preparedness and earthquake preparedness. Our results show that threat knowledge affects risk perception and disaster preparedness positively. In addition, disaster preparedness positively affects earthquake preparedness. However, the proposed paths from risk perception to disaster preparedness, risk perception to earthquake preparedness, and threat knowledge to earthquake preparedness were not statistically significant. Our results may provide references for policymakers in promoting crisis planning in tourism destination with high seismic risks.

  6. Impact of using lightweight eco-bricks as enclosures for individual houses of one story on zones of high seismicity

    Directory of Open Access Journals (Sweden)

    D. Dominguez

    2017-09-01

    Full Text Available Fired clay bricks are widely developed by focusing on the use of several wastes with the aim of obtaining lightweight materials. Despite research having provided positives experiences, most of these showed an important reduction of compression strength. This issue must be highlighted in particular, when seismic areas are considered. However, despite compression strength decreases in some cases the energy that can be absorbed by the brick might be increased. Hence, this paper tests and shows physical and mechanical properties of newly fired clays made by adding different percentages of sawdust. Results are used for calculating the response of an individual one-story house to medium intensity earthquakes. It is concluded that the use of bricks, with up to 5% sawdust added, is an ecological way for recycling these agro-wastes, while its behaviour against earthquakes performs better than other solutions, such as common perforated bricks.

  7. Impact of using lightweight eco-bricks as enclosures for individual houses of one story on zones of high seismicity

    International Nuclear Information System (INIS)

    Dominguez, D.; Muñoz, V.P.; Muñoz, V.L.

    2017-01-01

    Fired clay bricks are widely developed by focusing on the use of several wastes with the aim of obtaining lightweight materials. Despite research having provided positives experiences, most of these showed an important reduction of compression strength. This issue must be highlighted in particular, when seismic areas are considered. However, despite compression strength decreases in some cases the energy that can be absorbed by the brick might be increased. Hence, this paper tests and shows physical and mechanical properties of newly fired clays made by adding different percentages of sawdust. Results are used for calculating the response of an individual one-story house to medium intensity earthquakes. It is concluded that the use of bricks, with up to 5% sawdust added, is an ecological way for recycling these agro-wastes, while its behaviour against earthquakes performs better than other solutions, such as common perforated bricks. [es

  8. Edificio Cogesol, en Madrid

    Directory of Open Access Journals (Sweden)

    Alas, Genaro

    1964-05-01

    Full Text Available The functions to be met by this building were as follows. The housing of the necessary machinery for the manufacture of caffein free coffee, reception store, silo, stores, nightwatchman's house, offices, garage and workshop, dressing rooms. As the northern side, facing the Barajas highway, was the more important, the main building of the factory was placed on that side. Along the south, facing a secondary access road, the office block, the staff rooms and the watchman's house have been located. Between the two nuclei is the loading yard. The manufacturing tower has a metal structure, slender and smooth. The vertical and horizontal columns and beams have been hidden within the rear wall, the intermediate partition and the lift shaft. The main longitudinal stabilising member crosses this lift shaft, hence the former is discontinuous. The wind pressure acting on the tower is transmitted to the adjacent building, but as the two are separated by a dilation joint, flexible thrust connections are fitted between them. The long structural members were erected in sections, and the weldings were done with great care to avoid subsequent deformations, which would have shown on the smooth exterior. To an external observer the factory zone stands out clearly from the rest, for the tower is enclosed largely in transparent glass, so that all the machinery can be seen from outside. The stores, on the other hand, are enclosed with brick walls, and enhance the light and transparent quality of the tower. This contrast is further developed by the relative volumes and shapes of the various parts of the project, which produce an organic but spectacular sense of dynamic unity.El programa de necesidades se desarrolló según el siguiente esquema: edificio para la maquinaria destinada a la fabricación del café descafeinado, almacén de entrada, silo, almacenes varios, vivienda para el guarda, oficinas, garajes y taller y vestuario. Como de las dos fachadas principales

  9. Residencia para personas mayores en Villa del Prado, Madrid

    Directory of Open Access Journals (Sweden)

    García-Vaquero Alvaro, Javier

    2003-12-01

    Full Text Available Basic faci lities fo r socia l serv ices. Building designed as a home fo r the elderly, with 120 beds plus adult day care service for 40 seniors; erected under an agreement between the Madrid Housing Institute (IVIMA and the Regional Department ofFamily Affairs and Social Services in a small tOWlI in the region ofMadrid with a population of4.350. The design lends particular auention to zoning and spatial distribution based 0 11 a specific organisational chart as wel! as to daylight-related questions. The choice ofmaterials and colours is in keeping with the intended use ofthe building and the characteristics ofits users.Equipamiento Básico para Asistencia Social. Edificio destinado a Residencia pa ra Personas Mayores con una capacidad para 120 plazas residenciales con Centro de Estancias Diurnas para 40 plazas externas, realizado mediante Convenio entre el Instituto de la Vivienda de Madrid (IVIMA y la Consejeria de Familia y Servicios Sociales de la Comunidad de Madrid, en un pequeño municipio de esta Comunidad con una población de 4.350 habitantes. El proyecto dedica especial atención a la zonificación y a la distribució n espacial, en fu nci án de IIt I claro organigrama, y al manej o de la luz natural. La elección de materiales y colores se realiza en funci án del uso a que se destina el edificio ya las especiales características de sus usuarios.

  10. La nueva embajada alemana, en Madrid

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    Schoebel Ungria, G.

    1967-02-01

    Full Text Available This embassy involves two buildings, which, because of their style, appropriate aspect, the fine taste of their design, and the highly efficient manner in which the volumes agree with the building site, constitutes a singular ornament to one of the best zones of Madrid. All the materials are traditional in Spanish constructional practice, and were carefully chosen: their full plastic and chromatic quality being well utilised.Los dos edificios que componen el conjunto constituyen, por su tratamiento, por su representatividad, por el gusto con que han sido construidos y por el respetuoso trato dado a los volúmenes del aprovechamiento autorizado, un ornato singular en una de las zonas más nobles y vistosas de la capital de España. Todos los materiales empleados son los tradicionales del país anfitrión y fueron elegidos con esmero, conservándolos en toda su pureza plástica de carácter y cromática.

  11. Seismic ACROSS Transmitter Installed at Morimachi above the Subducting Philippine Sea Plate for the Test Monitoring of the Seismogenic Zone of Tokai Earthquake not yet to Occur

    Science.gov (United States)

    Kunitomo, T.; Kumazawa, M.; Masuda, T.; Morita, N.; Torii, T.; Ishikawa, Y.; Yoshikawa, S.; Katsumata, A.; Yoshida, Y.

    2008-12-01

    Here we report the first seismic monitoring system in active and constant operation for the wave propagation characteristics in tectonic region just above the subducting plate driving the coming catastrophic earthquakes. Developmental works of such a system (ACROSS; acronym for Accurately Controlled, Routinely Operated, Signal System) have been started in 1994 at Nagoya University and since 1996 also at TGC (Tono Geoscience Center) of JAEA promoted by Hyogoken Nanbu Earthquakes (1995 Jan.17, Mj=7.3). The ACROSS is a technology system including theory of signal and data processing based on the brand new concept of measurement methodology of Green function between a signal source and observation site. The works done for first generation system are reported at IWAM04 and in JAEA report (Kumazawa et al.,2007). The Meteorological Research Institute of JMA has started a project of test monitoring of Tokai area in 2004 in corporation with Shizuoka University to realize the practical use of the seismic ACROSS for earthquake prediction researches. The first target was set to Tokai Earthquake not yet to take place. The seismic ACROSS transmitter was designed so as to be appropriate for the sensitive monitoring of the deep active fault zone on the basis of the previous technology elements accumulated so far. The ground coupler (antenna) is a large steel-reinforced concrete block (over 20m3) installed in the basement rocks in order to preserve the stability. Eccentric moment of the rotary transmitter is 82 kgm at maximum, 10 times larger than that of the first generation. Carrier frequency of FM signal for practical use can be from 3.5 to 15 Hz, and the signal phase is accurately controlled by a motor with vector inverter synchronized with GPS clock with a precision of 10-4 radian or better. By referring to the existing structure model in this area (Iidaka et al., 2003), the site of the transmitting station was chosen at Morimachi so as to be appropriate for detecting the

  12. Modeling the seismic cycle in subduction zones: The role and spatiotemporal occurrence of off-megathrust earthquakes

    KAUST Repository

    van Dinther, Y.; Mai, Paul Martin; Dalguer, L. A.; Gerya, T. V.

    2014-01-01

    Shallow off-megathrust subduction events are important in terms of hazard assessment and coseismic energy budget. Their role and spatiotemporal occurrence, however, remain poorly understood. We simulate their spontaneous activation and propagation using a newly developed 2-D, physically consistent, continuum, viscoelastoplastic seismo-thermo-mechanical modeling approach. The characteristics of simulated normal events within the outer rise and splay and normal antithetic events within the wedge resemble seismic and seismological observations in terms of location, geometry, and timing. Their occurrence agrees reasonably well with both long-term analytical predictions based on dynamic Coulomb wedge theory and short-term quasi-static stress changes resulting from the typically triggering megathrust event. The impact of off-megathrust faulting on the megathrust cycle is distinct, as more both shallower and slower megathrust events arise due to occasional off-megathrust triggering and increased updip locking. This also enhances tsunami hazards, which are amplified due to the steeply dipping fault planes of especially outer rise events.

  13. Modeling the seismic cycle in subduction zones: The role and spatiotemporal occurrence of off-megathrust earthquakes

    KAUST Repository

    van Dinther, Y.

    2014-02-28

    Shallow off-megathrust subduction events are important in terms of hazard assessment and coseismic energy budget. Their role and spatiotemporal occurrence, however, remain poorly understood. We simulate their spontaneous activation and propagation using a newly developed 2-D, physically consistent, continuum, viscoelastoplastic seismo-thermo-mechanical modeling approach. The characteristics of simulated normal events within the outer rise and splay and normal antithetic events within the wedge resemble seismic and seismological observations in terms of location, geometry, and timing. Their occurrence agrees reasonably well with both long-term analytical predictions based on dynamic Coulomb wedge theory and short-term quasi-static stress changes resulting from the typically triggering megathrust event. The impact of off-megathrust faulting on the megathrust cycle is distinct, as more both shallower and slower megathrust events arise due to occasional off-megathrust triggering and increased updip locking. This also enhances tsunami hazards, which are amplified due to the steeply dipping fault planes of especially outer rise events.

  14. Seismic reflection-based evidence of a transfer zone between the Wagner and Consag basins: implications for defining the structural geometry of the northern Gulf of California

    Science.gov (United States)

    González-Escobar, Mario; Suárez-Vidal, Francisco; Hernández-Pérez, José Antonio; Martín-Barajas, Arturo

    2010-12-01

    This study examines the structural characteristics of the northern Gulf of California by processing and interpreting ca. 415 km of two-dimensional multi-channel seismic reflection lines (data property of Petróleos Mexicanos PEMEX) collected in the vicinity of the border between the Wagner and Consag basins. The two basins appear to be a link between the Delfín Superior Basin to the south, and the Cerro Prieto Basin to the north in the Mexicali-Imperial Valley along the Pacific-North America plate boundary. The seismic data are consistent with existing knowledge of four main structures (master faults) in the region, i.e., the Percebo, Santa María, Consag Sur, and Wagner Sur faults. The Wagner and Consag basins are delimited to the east by the Wagner Sur Fault, and to the west by the Consag Sur Fault. The Percebo Fault borders the western margin of the modern Wagner Basin depocenter, and is oriented N10°W, dipping (on average) ˜40° to the northeast. The trace of the Santa María Fault located in the Wagner Basin strikes N19°W, dipping ˜40° to the west. The Consag Sur Fault is oriented N14°W, and dips ˜42° to the east over a distance of 21 km. To the east of the study area, the Wagner Sur Fault almost parallels the Consag Sur Fault over a distance of ˜86 km, and is oriented N10°W with an average dip of 59° to the east. Moreover, the data provide new evidence that the Wagner Fault is discontinuous between the two basins, and that its structure is more complex than previously reported. A structural high separates the northern Consag Basin from the southern Wagner Basin, comprising several secondary faults oriented NE oblique to the main faults of N-S direction. These could represent a zone of accommodation, or transfer zone, where extension could be transferred from the Wagner to the Consag Basin, or vice versa. This area shows no acoustic basement and/or intrusive body, which is consistent with existing gravimetric and magnetic data for the region.

  15. Constraints on Shallow Crustal Structure across the San Andreas Fault Zone, Coachella Valley, Southern California: Results from the Salton Seismic Imaging Project (SSIP)

    Science.gov (United States)

    Hernandez, A.; Persaud, P.; Bauer, K.; Stock, J. M.; Fuis, G. S.; Hole, J. A.; Goldman, M.

    2015-12-01

    The strong influence of basin structure and crustal heterogeneities on seismic wave propagation suggests that these factors should be included in calculations of strong ground shaking. Knowledge of the shallow subsurface is thus essential for an accurate seismic hazard estimate for the densely populated Coachella Valley, the region north of the potential M7.8 rupture near the Salton Sea. Using SSIP data, we analyzed first arrivals from nine 65-911 kg explosive shots recorded along a profile in the Coachella Valley in order to evaluate the interpretation of our 2D tomographic results and give added details on the structural complexity of the shallow crust. The line extends 37 km from the Peninsular Ranges to the Little San Bernardino Mountains crossing the major strands of the San Andreas Fault Zone. We fit traveltime curves to our picks with forward modeling ray tracing, and determined 1D P-wave velocity models for traveltime arrivals east and west of each shot, and a 2D model for the line. We also inferred the geometry of near-vertical faults from the pre-stack line migration method of Bauer et al. (2013). In general, the 1D models east of individual shots have deeper basement contacts and lower apparent velocities, ~5 km/s at 4 km depth, whereas the models west of individual shots have shallower basement and velocities up to 6 km/s at 2 km depth. Mismatches in basement depths (assuming 5-6 km/s) between individual 1D models indicate a shallowly dipping basement, deepening eastward towards the Banning Fault and shoaling abruptly farther east. An east-dipping structure in the 2D model also gives a better fit than horizontal layers. Based on high velocity zones derived from traveltimes at 9-20 km from the western end of the line, we included an offset from ~2 km to 4 km depth near the middle of the line, which significantly improved the 2D model fit. If fault-related, this offset could represent the Garnet Hill Fault if it continues southward in the subsurface.

  16. Seismic testing

    International Nuclear Information System (INIS)

    Sollogoub, Pierre

    2001-01-01

    This lecture deals with: qualification methods for seismic testing; objectives of seismic testing; seismic testing standards including examples; main content of standard; testing means; and some important elements of seismic testing

  17. Use of Fault Displacement Vector to Identify Future Zones of Seismicity: An Example from the Earthquakes of Nepal Himalayas.

    Science.gov (United States)

    Naim, F.; Mukherjee, M. K.

    2017-12-01

    Earthquakes occur due to fault slip in the subsurface. They can occur either as interplate or intraplate earthquakes. The region of study is the Nepal Himalayas that defines the boundary of Indian-Eurasian plate and houses the focus of the most devastating earthquakes. The aim of the study was to analyze all the earthquakes that occurred in the Nepal Himalayas upto May 12, 2015 earthquake in order to mark the regions still under stress and vulnerable for future earthquakes. Three different fault systems in the Nepal Himalayas define the tectonic set up of the area. They are: (1) Main Frontal Thrust(MFT), (2) Main Central Thrust(MCT) and (3) Main Boundary Thrust(MBT) that extend from NW to SE. Most of the earthquakes were observed to occur between the MBT and MCT. Since the thrust faults are dipping towards NE, the focus of most of the earthquakes lies on the MBT. The methodology includes estimating the dip of the fault by considering the depths of different earthquake events and their corresponding distance from the MBT. In order to carry out stress analysis on the fault, the beach ball diagrams associated with the different earthquakes were plotted on a map. Earthquakes in the NW and central region of the fault zone were associated with reverse fault slip while that on the South-Eastern part were associated with a strike slip component. The direction of net slip on the fault associated with the different earthquakes was known and from this a 3D slip diagram of the fault was constructed. The regions vulnerable for future earthquakes in the Nepal Himalaya were demarcated on the 3D slip diagram of the fault. Such zones were marked owing to the fact that the slips due to earthquakes cause the adjoining areas to come under immense stress and this stress is directly proportional to the amount of slip occuring on the fault. These vulnerable zones were in turn projected on the map to show their position and are predicted to contain the epicenter of the future earthquakes.

  18. Seismic Velocity Structure of the San Jacinto Fault Zone from Double-Difference Tomography and Expected Distribution of Head Waves

    Science.gov (United States)

    Allam, A. A.; Ben-Zion, Y.

    2010-12-01

    We present initial results of double-difference tomographic images for the velocity structure of the San Jacinto Fault Zone (SJFZ), and related 3D forward calculations of waves in the immediate vicinity of the SJFZ. We begin by discretizing the SJFZ region with a uniform grid spacing of 500 m, extending 140 km by 80 km and down to 25 km depth. We adopt the layered 1D model of Dreger & Helmberger (1993) as a starting model for this region, and invert for 3D distributions of VP and VS with the double-difference tomography of Zhang & Thurber (2003), which makes use of absolute event-station travel times as well as relative travel times for phases from nearby event pairs. Absolute arrival times of over 78,000 P- and S-wave phase picks generated by 1127 earthquakes and recorded at 70 stations near the SJFZ are used. Only data from events with Mw greater than 2.2 are used. Though ray coverage is limited at shallow depths, we obtain relatively high-resolution images from 4 to 13 km which show a clear contrast in velocity across the NW section of the SJFZ. To the SE, in the so-called trifurcation area, the structure is more complicated, though station coverage is poorest in this region. Using the obtained image, the current event locations, and the 3D finite-difference code of Olsen (1994), we estimate the likely distributions of fault zone head waves as a tool for future deployment of instrument. We plan to conduct further studies by including more travel time picks, including those from newly-deployed stations in the SJFZ area, in order to gain a more accurate image of the velocity structure.

  19. Carbon monoxide degassing from seismic fault zones in the Basin and Range province, west of Beijing, China

    Science.gov (United States)

    Sun, Yutao; Zhou, Xiaocheng; Zheng, Guodong; Li, Jing; Shi, Hongyu; Guo, Zhengfu; Du, Jianguo

    2017-11-01

    Degassing of carbon monoxide (CO), which plays a significant role in the contribution of deep carbon to the atmosphere, commonly occurs within active fault zones. CO degassing from soil to the atmosphere in the Basin and Range province, west of Beijing (BRPB), China, was investigated by in-situ field measurements in the active fault zones. The measured concentrations of CO in soil gas in the BRPB ranged from 0.29 × 10-6 to 1.1 × 10-6 with a mean value of 0.6 × 10-6, which is approximately twice as large as that in the atmosphere. Net fluxes of CO degassing ranged from -48.6 mg m-2 d-1 to 12.03 mg m-2 d-1. The diffusion of CO from soil to the atmosphere in the BRPB was estimated to be at least 7.6 × 103 ton/a, which is comparable to the corresponding result of about 1.2 × 104 ton/a for CO2. CO concentrations were spatially heterogeneous with clearly higher concentrations along the NE-SW trending in the BRPB. These elevated values of CO concentrations were also coincident with the region with low-velocity and high conductivity in deep mantle, and high Poisson's ratio in the crust, thereby suggesting that CO degassing from the soil might be linked to upwelling of the asthenospheric mantle. Other sources of CO in the soil gas are suggested to be dominated by chemical reactions between deep fluids and carbonate minerals (e.g., dolomite, limestone, and siderite) in country rocks. Biogenic processes may also contribute to the CO in soil gas. The spatial distribution patterns of CO concentrations are coincident with the stress field, suggesting that the concentrations of CO could be a potential indicator for crustal stress field and, hence is potential useful for earthquake monitoring in the BRPB.

  20. AstroMadrid: Astrophysics and technological developments in Comunidad de Madrid

    Science.gov (United States)

    Mas-Hesse, J. M.

    2011-11-01

    AstroMadrid is a network constituted by different research groups in the Comunidad de Madrid area, with the objective of coordinating the activities related to the development of astronomical instrumentation in the various centres. AstroMadrid is a multidisciplinar team which benefits from the synergies provided by the different participating groups, optimizing our capabilities to develop instrumentation, and minimizing the problems related to the geographical dispersion within our region. AstroMadrid is also participated by several aerospace industries, which complement the capabilities and facilities available in the research centres. In addition to optimizing the development of instrumentation, AstroMadrid plays an essential role in the formation of new engineers and scientists, by actively contributing to some Master degree courses organized by different Universities in Madrid.

  1. Crustal structure and mantle transition zone thickness beneath a hydrothermal vent at the ultra-slow spreading Southwest Indian Ridge (49°39'E): a supplementary study based on passive seismic receiver functions

    Science.gov (United States)

    Ruan, Aiguo; Hu, Hao; Li, Jiabiao; Niu, Xiongwei; Wei, Xiaodong; Zhang, Jie; Wang, Aoxing

    2017-06-01

    As a supplementary study, we used passive seismic data recorded by one ocean bottom seismometer (OBS) station (49°41.8'E) close to a hydrothermal vent (49°39'E) at the Southwest Indian Ridge to invert the crustal structure and mantle transition zone (MTZ) thickness by P-to-S receiver functions to investigate previous active seismic tomographic crustal models and determine the influence of the deep mantle thermal anomaly on seafloor hydrothermal venting at an ultra-slow spreading ridge. The new passive seismic S-wave model shows that the crust has a low velocity layer (2.6 km/s) from 4.0 to 6.0 km below the sea floor, which is interpreted as partial melting. We suggest that the Moho discontinuity at 9.0 km is the bottom of a layer (2-3 km thick); the Moho (at depth of 6-7 km), defined by active seismic P-wave models, is interpreted as a serpentinized front. The velocity spectrum stacking plot made from passive seismic data shows that the 410 discontinuity is depressed by 15 km, the 660 discontinuity is elevated by 18 km, and a positive thermal anomaly between 182 and 237 K is inferred.

  2. Changing theory, changing role of Coriolis effect - The East-West asymmetry of the Wadati-Benioff seismic zones

    Science.gov (United States)

    Scalera, Giancarlo

    2014-05-01

    It is a long history the tale of the recognized asymmetries of the Earth. In 1600 William Gilbert (1544-1603) published De Magnete in which the North and South geomagnetic pole are described. In 1620 Francis Bacon (1561-1628) in the XXVIIth aphorism of the Novum Organum (second part) describes the southern tips of the continents, and many other asymmetries were later described. In 1975 Samuel Warren Carey (1911-2002) stated: Neither north and south, nor east and west are tectonically equivalent. A non exhaustive list of asymmetries of the Earth is: The magnetic polarity; The land-hemisphere and the water-hemisphere; Southern tips of the continents; Larger extension of expanding mid-oceanic ridges on the southern hemisphere; South-eastward trend of younger ages in the long Pacific seafloor volcanic chains; A larger width of the seafloor isochrones bands on the Nazca region; A pear-shaped Earth; etc. It is a few decades that the different slopes of the Wadati-Benioff zones oriented towards the east and west has been enclosed in the list. Under the Americas they have angles of about 30 degrees, while under the Pacific east coasts (Asia, Japan) the angles are steeper (Luyendyk, 1970; Isacks & Barazangi, 1977; and many others). The cause of this difference has been identified in the tidal drag that would cause a global shift of the lithosphere towards west - the so called westward drift (Bostrom, 1971; Stevenson & Turner, 1977; among others). This solution has been many times criticized on the basis of the irrelevance of the tidal forces with respect to viscous friction (Jordan, 1974; Ranalli, 2000; Caputo & Caputo, 2012). Moreover, a simplistic evaluation of the regime of the convective motion in the mantle and of the order of magnitude of the involved forces (viscous, buoyancy, inertial) hastily judges as negligible the role of the Coriolis effect in producing the observed slope differences of the Wadati-Benioff regions. Instead, it is possible to show that changing

  3. Incorporating fault zone head wave and direct wave secondary arrival times into seismic tomography: Application at Parkfield, California

    Science.gov (United States)

    Bennington, Ninfa L.; Thurber, Clifford; Peng, Zhigang; Zhang, Haijiang; Zhao, Peng

    2013-03-01

    We present a three-dimensional (3D) P wave velocity (Vp) model of the Parkfield region that utilizes existing P wave arrival time data, including fault zone head waves (FZHWs), and data from direct wave secondary arrivals (DWSAs). The first-arrival and DWSA travel times are obtained as the global- and local-minimum travel time paths, respectively. The inclusion of FZHWs and DWSAs results in as much as a 5% and a 10% increase in the across-fault velocity contrast, respectively, for the Vp model at Parkfield relative to that of Thurber et al. [2006]. Viewed along strike, three pronounced velocity contrast regions are observed: a pair of strong positive velocity contrasts (SW fast), one NW of the 1966 Parkfield earthquake hypocenter and the other SE of the 2004 Parkfield earthquake hypocenter, and a strong negative velocity contrast (NE fast) between the two hypocenters. The negative velocity contrast partially to entirely encompasses peak coseismic slip estimated in several slip models for the 2004 earthquake, suggesting that the negative velocity contrast played a part in defining the rupture patch of the 2004 Parkfield earthquake. Following Ampuero and Ben-Zion (2008), the pattern of velocity contrasts is consistent with the observed bilateral rupture propagation for the 2004 Parkfield earthquake. Although the velocity contrasts also suggest bilateral rupture propagation for the 1966 Parkfield earthquake, the fault is creeping to the NW here, i.e., exhibiting velocity-strengthening behavior. Thus, it is not surprising that rupture propagated only SE during this event.

  4. Crustal structure beneath two seismic stations in the Sunda-Banda arc transition zone derived from receiver function analysis

    Energy Technology Data Exchange (ETDEWEB)

    Syuhada, E-mail: hadda9@gmail.com [Graduate Research on Earthquake and Active Tectonics (GREAT), Bandung Institute of Technology, Jalan Ganesha 10, Bandung 40132 (Indonesia); Research Centre for Physics - Indonesian Institute of Sciences (LIPI), Kompleks Puspiptek Serpong, Tangsel 15314, Banten Indonesia (Indonesia); Hananto, Nugroho D.; Handayani, Lina [Research Centre for Geotechnology - Indonesian Institute of Sciences (LIPI), Jl. Sangkuriang (Kompleks LIPI) Bandung 40135 (Indonesia); Puspito, Nanang T; Yudistira, Tedi [Faculty of Mining and Petroleum Engineering ITB, Jalan Ganesha 10, Bandung 40132 (Indonesia); Anggono, Titi [Research Centre for Physics - Indonesian Institute of Sciences (LIPI), Kompleks Puspiptek Serpong, Tangsel 15314, Banten Indonesia (Indonesia)

    2015-04-24

    We analyzed receiver functions to estimate the crustal thickness and velocity structure beneath two stations of Geofon (GE) network in the Sunda-Banda arc transition zone. The stations are located in two different tectonic regimes: Sumbawa Island (station PLAI) and Timor Island (station SOEI) representing the oceanic and continental characters, respectively. We analyzed teleseismic events of 80 earthquakes to calculate the receiver functions using the time-domain iterative deconvolution technique. We employed 2D grid search (H-κ) algorithm based on the Moho interaction phases to estimate crustal thickness and Vp/Vs ratio. We also derived the S-wave velocity variation with depth beneath both stations by inverting the receiver functions. We obtained that beneath station PLAI the crustal thickness is about 27.8 km with Vp/Vs ratio 2.01. As station SOEI is covered by very thick low-velocity sediment causing unstable solution for the inversion, we modified the initial velocity model by adding the sediment thickness estimated using high frequency content of receiver functions in H-κ stacking process. We obtained the crustal thickness is about 37 km with VP/Vs ratio 2.2 beneath station SOEI. We suggest that the high Vp/Vs in station PLAI may indicate the presence of fluid ascending from the subducted plate to the volcanic arc, whereas the high Vp/Vs in station SOEI could be due to the presence of sediment and rich mafic composition in the upper crust and possibly related to the serpentinization process in the lower crust. We also suggest that the difference in velocity models and crustal thicknesses between stations PLAI and SOEI are consistent with their contrasting tectonic environments.

  5. The incorporation of fault zone head wave and direct wave secondary arrival times and arrival polarizations into seismic tomography: Application to the Parkfield, California area

    Science.gov (United States)

    Bennington, N. L.; Thurber, C. H.; Peng, Z.; Zhao, P.

    2012-12-01

    We present a 3D P-wave velocity (Vp) model of the Parkfield region that utilizes existing P-wave arrival time data, including fault zone head waves (FZHW), plus new data from direct wave secondary arrivals (DWSA). The first-arrival and DWSA travel times are obtained as the global and local minimum travel time paths, respectively. The inclusion of DWSA results in as much as a 10% increase in the across-fault velocity contrast for the Vp model at Parkfield relative to Thurber et al. (2006). Viewed along strike, three pronounced velocity contrast regions are observed: a pair of strong positive velocity contrasts (SW fast), one NW of the 1966 Parkfield hypocenter and the other SE of the 2004 Parkfield hypocenter, and a strong negative velocity contrast (NE fast) between the two hypocenters. The negative velocity contrast partially to entirely encompasses peak coseismic slip estimated in several slip models for the 2004 earthquake, suggesting that the negative velocity contrast played a part in defining the rupture patch of the 2004 Parkfield earthquake. We expand on this work by modifying our seismic tomography algorithm to incorporate arrival polarizations (azimuths). Synthetic tests will be presented to demonstrate the improvements in velocity structure when arrival polarizations are incorporated. These tests will compare the synthetic model recovered when FZHW/DWSA arrivals as well as existing P-wave arrival time data are inverted to that recovered with the same dataset with the inclusion of arrival polarizations. We plan to extend this work to carry out a full scale seismic tomography/relocation inversion at Parkfield, CA utilizing arrival polarizations from all first-P arrivals, and FZHW/DWSA arrivals as well as existing P-wave arrival time data. This effort requires the determination of polarization data for all P-waves and FZHW's at Parkfield. To this end, we use changes in the arrival azimuth from fault normal to source-receiver direction to identify FZHW and

  6. Seismic images of the transition zone: is Hawaiian volcanism produced by a secondary plume from the top of the lower mantle?

    Science.gov (United States)

    Cao, Q.; van der Hilst, R. D.; Shim, S.; De Hoop, M. V.

    2011-12-01

    The Hawaiian hotspot is often attributed to hot material rising from depth in the mantle, but efforts to detect a thermal plume seismically have been inconclusive. Most tomographic models reveal anomalously low wavespeeds beneath Hawaii, but the depth extent of this structure is not well known. S or P data used in traveltime inversions are associated with steep rays to distant sources, which degrades depth resolution, and surface wave dispersion does not have sufficient sensitivity at the depths of interest. To investigate pertinent thermal anomalies we mapped depth variations of upper mantle discontinuities using precursors of the surface-reflected SS wave. Instead of stacking the data over geographical bins, which leads to averaging of topography and hence loss of spatial resolution, we used a generalized Radon transform (GRT) to detect and map localized elasticity contrasts in the transition zone (Cao et al., PEPI, 2010). We apply the GRT to produce 3D image volumes beneath a large area of the Pacific Ocean, including Hawaii and the Hawaii-Emperor seamount chain (Cao et al., Science, 2011). The 3D image volumes reveal laterally continuous interfaces near 410 and 660 km depths, that is, the traditional boundaries of the transition zone, but also suggest (perhaps intermittent) scatter horizons near 300-350, 520-550, and 800-1000 km depth. The upper mantle appears generally hot beneath Hawaii, but the most conspicuous topographic (and probably thermal) anomalies are found west of Hawaii. The GRT images reveal a 800 km wide uplift of the 660 discontinuity just west of Hawaii, but there is no evidence for a corresponding localized depression of the 410 discontinuity. This expression of the 410 and 660 km topographies is consistent with some existed geodynamical modeling results, in which a deep-rooted mantle plume impinging on the transition zone, creating a broad pond of hot material underneath endothermic phase change at 660 km depth, and with secondary plumes

  7. Wind energy resource assessment in Madrid region

    Energy Technology Data Exchange (ETDEWEB)

    Migoya, Emilio; Crespo, Antonio; Jimenez, Angel; Garcia, Javier; Manuel, Fernando [Laboratorio de Mecanica de Fluidos, Departamento de Ingenieria Energetica y Fluidomecanica, Escuela Tecnica Superior Ingenieros Industriales (ETSII), Universidad Politecnica de Madrid (UPM), C/Jose Gutierrez Abascal, 2-28006, Madrid (Spain)

    2007-07-15

    The Comunidad Autonoma de Madrid (Autonomous Community of Madrid, in the following Madrid Region), is a region located at the geographical centre of the Iberian Peninsula. Its area is 8.028 km{sup 2}, and its population about five million people. The Department of Economy and Technological Innovation of the Madrid Region, together with some organizations dealing on energy saving and other research institutions have elaborated an Energy Plan for the 2004-12 period. As a part of this work, the Fluid Mechanics Laboratory of the Superior Technical School of Industrial Engineers of the Polytechnic University of Madrid has carried out the assessment of the wind energy resources [Crespo A, Migoya E, Gomez Elvira R. La energia eolica en Madrid. Potencialidad y prospectiva. Plan energetico de la Comunidad de Madrid, 2004-2012. Madrid: Comunidad Autonoma de Madrid; 2004]; using for this task the WAsP program (Wind Atlas Analysis and Application Program), and the own codes, UPMORO (code to study orography effects) and UPMPARK (code to study wake effects in wind parks). Different kinds of data have been collected about climate, topography, roughness of the land, environmentally protected areas, town and village distribution, population density, main facilities and electric power supply. The Spanish National Meteorological Institute has nine wind measurement stations in the region, but only four of them have good and reliable temporary wind data, with time measurement periods that are long enough to provide representative correlations among stations. The Observed Wind Climates of the valid meteorological stations have been made. The Wind Atlas and the resource grid have been calculated, especially in the high wind resource areas, selecting appropriate measurements stations and using criteria based on proximity, similarity and ruggedness index. Some areas cannot be used as a wind energy resource mainly because they have environmental regulation or, in some cases, are very close

  8. Recasting Madrid and Its Characters in Munoz Molina's "Los misterios de Madrid"

    Science.gov (United States)

    Long, Sheri Spaine

    2009-01-01

    "Los misterios de Madrid" (1992) provides a burlesque novelistic portrayal of the changing capital city and its inhabitants in the early 1990s. Spanish writer Antonio Munoz Molina creates vignettes of Madrid's people and places while showing the capital as a destination for both foreign-born immigrants and provincial Spaniards alike. In…

  9. Syntectonic Mississippi River Channel Response: Integrating River Morphology and Seismic Imaging to Detect Active Faults

    Science.gov (United States)

    Magnani, M. B.

    2017-12-01

    Alluvial rivers, even great rivers such as the Mississippi, respond to hydrologic and geologic controls. Temporal variations of valley gradient can significantly alter channel morphology, as the river responds syntectonically to attain equilibrium. The river will alter its sinuosity, in an attempt to maintain a constant gradient on a surface that changes slope through time. Therefore, changes of river pattern can be the first clue that active tectonics is affecting an area of pattern change. Here I present geomorphological and seismic imaging evidence of a previously unknown fault crossing the Mississippi river south of the New Madrid seismic zone, between Caruthersville, Missouri and Osceola, Arkansas, and show that both datasets support Holocene fault movement, with the latest slip occurring in the last 200 years. High resolution marine seismic reflection data acquired along the Mississippi river imaged a NW-SE striking north-dipping fault displacing the base of the Quaternary alluvium by 15 m with reverse sense of movement. The fault consistently deforms the Tertiary, Cretaceous and Paleozoic formations. Historical river channel planforms dating back to 1765 reveal that the section of the river channel across the fault has been characterized by high sinuosity and steep projected-channel slope compared to adjacent river reaches. In particular, the reach across the fault experienced a cutoff in 1821, resulting in a temporary lowering of sinuosity followed by an increase between the survey of 1880 and 1915. Under the assumption that the change in sinuosity reflects river response to a valley slope change to maintain constant gradient, I use sinuosity through time to calculate the change in valley slope since 1880 and therefore to estimate the vertical displacement of the imaged fault in the past 200 years. Based on calculations so performed, the vertical offset of the fault is estimated to be 0.4 m, accrued since at least 1880. If the base of the river alluvium

  10. Monitoring diffuse degassing in monogenetic volcanic field during seismic-volcanic unrest: the case of Tenerife North-West Rift Zone (NWRZ), Canary Islands, Spain

    Science.gov (United States)

    García, E.; Botelho, A. H.; Regnier, G. S. G.; Rodríguez, F.; Alonso Cótchico, M.; Melián, G.; Asensio-Ramos, M.; Padrón, E.; Hernández, P. A.; Pérez, N. M.

    2017-12-01

    factors and it shows a clear temporal correlation with the onsets of seismic activity (Hernández et al., 2017, Bull. Volcanol.). Monitoring the diffuse CO2 emission contributes to detect early warning signals of volcanic unrest at the Tenerife North-West Rift-Zone volcano.

  11. Near-vertical seismic reflection image using a novel acquisition technique across the Vrancea Zone and Foscani Basin, south-eastern Carpathians (Romania).

    NARCIS (Netherlands)

    Panea, I; Stephenson, R.A.; Knapp, C.; Mocanu, V.I.; Drijkoningen, G.; Matenco, L.C.; Knapp, J.; Prodehl, K.

    2005-01-01

    The DACIA PLAN (Danube and Carpathian Integrated Action on Process in the Lithosphere and Neotectonics) deep seismic sounding survey was performed in August-September 2001 in south-eastern Romania, at the same time as the regional deep refraction seismic survey VRANCEA 2001. The main goal of the

  12. Airborne LiDAR analysis and geochronology of faulted glacial moraines in the Tahoe-Sierra frontal fault zone reveal substantial seismic hazards in the Lake Tahoe region, California-Nevada USA

    Science.gov (United States)

    Howle, James F.; Bawden, Gerald W.; Schweickert, Richard A.; Finkel, Robert C.; Hunter, Lewis E.; Rose, Ronn S.; von Twistern, Brent

    2012-01-01

    We integrated high-resolution bare-earth airborne light detection and ranging (LiDAR) imagery with field observations and modern geochronology to characterize the Tahoe-Sierra frontal fault zone, which forms the neotectonic boundary between the Sierra Nevada and the Basin and Range Province west of Lake Tahoe. The LiDAR imagery clearly delineates active normal faults that have displaced late Pleistocene glacial moraines and Holocene alluvium along 30 km of linear, right-stepping range front of the Tahoe-Sierra frontal fault zone. Herein, we illustrate and describe the tectonic geomorphology of faulted lateral moraines. We have developed new, three-dimensional modeling techniques that utilize the high-resolution LiDAR data to determine tectonic displacements of moraine crests and alluvium. The statistically robust displacement models combined with new ages of the displaced Tioga (20.8 ± 1.4 ka) and Tahoe (69.2 ± 4.8 ka; 73.2 ± 8.7 ka) moraines are used to estimate the minimum vertical separation rate at 17 sites along the Tahoe-Sierra frontal fault zone. Near the northern end of the study area, the minimum vertical separation rate is 1.5 ± 0.4 mm/yr, which represents a two- to threefold increase in estimates of seismic moment for the Lake Tahoe basin. From this study, we conclude that potential earthquake moment magnitudes (Mw) range from 6.3 ± 0.25 to 6.9 ± 0.25. A close spatial association of landslides and active faults suggests that landslides have been seismically triggered. Our study underscores that the Tahoe-Sierra frontal fault zone poses substantial seismic and landslide hazards.

  13. Multicomponent seismic applications in coalbed methane development

    Energy Technology Data Exchange (ETDEWEB)

    Lawton, D.; Trend, S. [Calgary Univ., AB (Canada). Dept. of Geology and Geophysics

    2004-07-01

    Seismic applications for coalbed methane (CBM) development are used to address the following challenges: lateral continuity of coal zones; vertical continuity of coal seams; permeability of cleats and fractures; coal quality and gas content; wet versus dry coal zones; and, monitoring storage of greenhouse gases. This paper presented a brief description of existing seismic programs, including 2-D and 3-D surface seismic surveys; multicomponent seismic surveys; vertical seismic profiles; cross-well seismic surveys; and, time-lapse seismic surveys. A comparative evaluation of their use in the Horseshoe Canyon Formation and the Ardley Formation was presented. The study showed that variations in reservoir properties resulting from gas production and dewatering can be effectively imaged using seismic surveys. Seismic surveys are useful in reservoir management, monitoring sweep efficiency during enhanced natural gas from coal (NGC) production, monitoring disposal of produced water and verifying storage of carbon dioxide for carbon credits. tabs., figs.

  14. Madrid principles of Nagorno-Karabakh settlement

    Directory of Open Access Journals (Sweden)

    K K Babayan

    2014-12-01

    Full Text Available As part of this work presents the analysis of the basic document and the legal framework of the peace settlement of the Nagorno-Karabakh conflict on the modern stage - «Madrid or Basic principles», presented to the sides of the negotiations at the OSCE ministerial conference in the Spanish capital Madrid in November 2007. The both side’s statements, international mediators and institutes form a legal background of the vector and the framework of the negotiation process. There are the fundamental differences and contradictions in the approaches of the sides of the negotiations to the «Basic principles» of the settlement in this article. The work contains a comparison of the various items and elements of the Madrid document both in relation to each other, and to the principles of international law.

  15. Ciudad Mercado, infraestructura en red. Madrid.

    OpenAIRE

    Carruthers, Luz María

    2016-01-01

    Los mercados de abastos de Madrid atraviesan uno profunda crisis que conlleva su decadencia arquitectónica. Si bien han sido una pieza el clave en la construcción social y urbana de Madrid. no son considerados una infraestructura, lo cual repercute en el tipo y calidad de intervenciones a los que se los somete. Recuperar su condición infraestructura, supone pensar en los mercados como red, enfocándose en las interacciones que plantean con el entorno a múltiples escalas. Éstas, pueden deber...

  16. Marfiles Coptos en Valdetorres de Jarama (Madrid

    Directory of Open Access Journals (Sweden)

    Marta Carrasco

    2018-01-01

    Full Text Available Presentation of a series of carved ivory coming from the villa de Valdetorres de Jarama, Madrid. All of them seemed to be imported pieces coming from Egypt, and could be dated between the late fourth century and the first half of the fifth century a.C. We could theoretically reconstruit chests or decorative panels with them.

  17. Seismicity and tectonics of Bangladesh

    International Nuclear Information System (INIS)

    Hossain, K.M.

    1989-05-01

    Northern and eastern Bangladesh and surrounding areas belong to a seismically active zone and are associated with the subduction of the Indian plate. The seismicity and tectonics have been studied in detail and the observations have been correlated to understand the earthquake phenomenon in the region. The morphotectonic behaviour of northern Bangladesh shows that it is deeply related to the movement of the Dauki fault system and relative upliftment of the Shillong plateau. Contemporary seismicity in the Dauki fault system is relatively quiet comparing to that in the Naga-Disang-Haflong thrust belt giving rise to the probability of sudden release of energy being accumulated in the vicinity of the Dauki fault system. This observation corresponds with the predicted average return period of a large earthquake (1897 type) and the possibility of M > 8 earthquake in the vicinity of the Dauki fault within this century should not be ruled out. The seismicity in the folded belt in the east follows the general trend of Arakan-Yoma anticlinorium and represents shallow and low-angled thrust movements in conformity with the field observation. Seismotectonic behaviour in the deep basin part of Bangladesh demonstrates that an intraplate movement in the basement rock has been taking place along the deep-seated faults causing relative upliftment and subsidence in the basin. Bangladesh has been divided into three seismic zones on the basis of morphotectonic and seismic behaviour. Zone-I has been identified as the zone of high seismic risk. (author). 43 refs, 5 figs, 3 tabs

  18. Community projects based on Art & Health: A collaboration between the Faculty of Fine Arts at the Complutense University of Madrid and Madrid city council's Madrid Salud Service

    OpenAIRE

    Ávila, Noemí; Orellana, Ana M.; Claver, María Dolores; Borrego Hernando, Olga; Antúnez, Noelia; García Cano, Marta; Segura del Pozo, Javier; Belver, Manuel H.; Martínez Cortés, Mercedes; Martínez, Catalina; Jambers, Brigitte; Cortés, Fátima; Yeves, Laura; Soto, María del Carmen; Saavedra Macías, Francisco Javier (Coordinador)

    2017-01-01

    In 2011 the Faculty of Fine Arts at the Complutense University of Madrid, and Madrid City Council's Health Promotion and Prevention Service (Madrid Salud Service) signed a collaboration agreement for developing joint projects and activities. This mutual collaboration agreement has generated an extremely active working network, in which university students supported by health service professionals plus Faculty academics and researchers have designed, and developed, community projects based on ...

  19. Imaging Stress Transients and Fault Zone Processes with Crosswell Continuous Active-Source Seismic Monitoring at the San Andreas Fault Observatory at Depth

    Science.gov (United States)

    Niu, F.; Taira, T.; Daley, T. M.; Marchesini, P.; Robertson, M.; Wood, T.

    2017-12-01

    Recent field and laboratory experiments identify seismic velocity changes preceding microearthquakes and rock failure (Niu et al., 2008, Nature; Scuderi et al., 2016, NatureGeo), which indicates that a continuous monitoring of seismic velocity might provide a mean of understanding of the earthquake nucleation process. Crosswell Continuous Active-Source Seismic Monitoring (CASSM) using borehole sources and sensors has proven to be an effective tool for measurements of seismic velocity and its temporal variation at seismogenic depth (Silver, et al, 2007, BSSA; Daley, et al, 2007, Geophysics). To expand current efforts on the CASSM development, in June 2017 we have begun to conduct a year-long CASSM field experiment at the San Andreas Fault Observatory at Depth (SAFOD) in which the preceding field experiment detected the two sudden velocity reductions approximately 10 and 2 hours before microearthquakes (Niu et al., 2008, Nature). We installed a piezoelectric source and a three-component accelerometer at the SAFOD pilot and main holes ( 1 km depth) respectively. A seismic pulse was fired from the piezoelectric source four times per second. Each waveform was recorded 150-ms-long data with a sampling rate of 48 kHz. During this one-year experiment, we expect to have 10-15 microearthquakes (magnitude 1-3) occurring near the SAFOD site, and the data collected from the new experiment would allow us to further explore a relation between velocity changes and the Parkfield seismicity. Additionally, the year-long data provide a unique opportunity to study long-term velocity changes that might be related to seasonal stress variations at Parkfield (Johnson et al., 2017, Science). We will report on initial results of the SAFOD CASSM experiment and operational experiences of the CASSM development.

  20. Seismic hazard assessment of Iran

    Directory of Open Access Journals (Sweden)

    M. Ghafory-Ashtiany

    1999-06-01

    Full Text Available The development of the new seismic hazard map of Iran is based on probabilistic seismic hazard computation using the historical earthquakes data, geology, tectonics, fault activity and seismic source models in Iran. These maps have been prepared to indicate the earthquake hazard of Iran in the form of iso-acceleration contour lines, and seismic hazard zoning, by using current probabilistic procedures. They display the probabilistic estimates of Peak Ground Acceleration (PGA for the return periods of 75 and 475 years. The maps have been divided into intervals of 0.25 degrees in both latitudinal and longitudinal directions to calculate the peak ground acceleration values at each grid point and draw the seismic hazard curves. The results presented in this study will provide the basis for the preparation of seismic risk maps, the estimation of earthquake insurance premiums, and the preliminary site evaluation of critical facilities.

  1. [Spatial analysis of syphilis and gonorrhea infections in a Public Health Service in Madrid].

    Science.gov (United States)

    Wijers, Irene G M; Sánchez Gómez, Amaya; Taveira Jiménez, Jose Antonio

    2017-06-21

    Sexually transmitted diseases are a significant public health problem. Within the Madrid Autonomous Region, the districts with the highest syphilis and gonorrhea incidences are part of the same Public Health Service (Servicio de Salud Pública del Área 7, SSPA 7). The objective of this study was to identify, by spatial analysis, clusters of syphilis and gonorrhea infections in this SSPA in Madrid. All confirmed syphilis and gonorrhea cases registered in SSPA 7 in Madrid were selected. Moran's I was calculated in order to identify the existence of spatial autocorrelation and a cluster analysis was performed. Clusters and cumulative incidences (CI) per health zone were mapped. The district with most cases was Centro (CI: 67.5 and 160.7 per 100.000 inhabitants for syphilis and gonorrhea, respectively) with the highest CI (120.0 and 322.6 per 100.000 inhabitants) in the Justicia health zone.91.6% of all syphilis cases and 89.6% of gonorrhea cases were among men who have sex with men (MSM). Moran's I was 0.54 and 0.55 (p=0.001) for syphilis and gonorrhea, respectively. For syphilis, a cluster was identified including the six health zones of the Centro district, with a relative risk (RR)of 6.66 (p=0.001). For gonorrhea, a cluster was found including the Centro district, three health zones of the Chamberí district and one of Latina (RR 5.05; p=0.001). Centro was the district with most cases of syphilis and gonorrhea and the most affected population were MSM. For both infections, clusters were found with an important overlap. By identifying the most vulnerable health zones and populations, these results can help to design public health measures for preventing sexually transmitted diseases.

  2. Casa de viviendas en Madrid

    Directory of Open Access Journals (Sweden)

    Lamela Martínez, Antonio

    1963-09-01

    Full Text Available This building occupies a site of 1990 sq. ms, and includes 29 apartments distributed in a semi ground floor, five standard floor levels, an attic and a double attic. The services have been located in a second basement, and the ground floor and first basement are being devoted to commercial uses, such as shops. In order to provide more free space for the commercial zone, the beginning of the stairs and the entry to the lifts is situated on the semi ground floor level. The porter's quarters, refuse reception cubicle and porter's hall have also been placed at this level. The basic nuclei of the apartments are clearly separated into zones daytime living quarters, night quarters and services. It is noteworthy that passages have been largely eliminated, and circulation problems have been otherwise solved, avoiding to some extent the crossing of the main lines of human circulation. The area devoted to social life has been increased as far as possible, and its environment has been enlarged by means of balcony-terraces. The fine aesthetic quality of the building, in its external aspect, is largely due to the clever way in which the materials have been used, exploiting their textures and combining these harmoniously.Ha sido construida sobre un solar de 1.991,41 m2 y consta de 29 viviendas distribuidas en cinco plantas- tipo, ático, doble ático y entreplanta. Los servicios generales de la casa están situados en el segundo sótano; la planta baja y el primer sótano albergan los locales comerciales. Para conseguir una mayor superficie en dichos locales se ha adoptado la solución de situar el arranque de escalera y ascensores en la entreplanta, donde, asimismo, aparecen ubicados los servicios de vigilancia, cuarto de recepción de basuras y vivienda del portero.

  3. Evidences of Paleoearthquakes in Palaeolithic settlements within fluvial sequences of the Tagus Basin (Madrid, Central Spain).

    Science.gov (United States)

    Silva, Pablo G.; Rodríguez Pascua, M. A.; Pérez López, R.; Giner Robles, J. L.; Roquero, E.; Tapias, F.; López Recio, M.; Rus, I.; Morin, J.

    2010-05-01

    Multiple evidences of soft-sediment to brittle deformation within the Pleistocene fluvial terraces of the Tagus, Jarama, Tajuña and Manzanares river valleys have been described since the middle 20th Century. Cryoturbation, hydroplastic deformations due to underlying karstic collapses or halokinesis on the substratum of neogene gypsums, and seismic shaking have been proposed to interpret these structures. These deformations are typically concentrated in the +18-20 m terrace levels, and closely linked to well-known Palaeolithic sites, in some cases overlaying and/or affecting true prehistoric settlements (i.e. Arganda, Arriaga and Tafesa sites) within the Jarama and Manzanares valleys. The affected settlements typically display acheulian lithic industry linked to the scavenging of large Pleistocene mammals (i.e. Elephas antiquus). Commonly, deformational structures are concentrated in relatively thin horizons (10-50 cm thick) bracketed by undeformed fluvial sands and gravels. The soft-sediment deformations usually consist on medium to fine sized sands injected and protruded in overlaying flood-plain clayey silts, showing a wide variety of convolutes, injections, sand-dikes, dish and pillar structures, mud volcanoes, faults and folds, some times it is possible to undertake their 3D geometrical analysis due to the exceptional conservation of the structures (Tafesa). Recent geo-archaeological prospecting on the for the Palaeolithic Site of Arriaga (South Madrid City) conducted during the year 2009, let to find out an exceptional horizon of deformation of about 1.20 m thick. It consisted on highly disturbed and pervasively liquefacted sands, which hardly can be attributed to no-seismic processes. The acheulian lithic industry of the Madrid Region have been classically attributed the Late Middle Pleistocene (Comunidad de Madrid, AUDEMA S.A. (Proyecto Arriaga-2009). This is a contribution of GQM-AEQUA.

  4. Global seasonal strain and stress models derived from GRACE loading, and their impact on seismicity

    Science.gov (United States)

    Chanard, K.; Fleitout, L.; Calais, E.; Craig, T. J.; Rebischung, P.; Avouac, J. P.

    2017-12-01

    Loading by continental water, atmosphere and oceans deforms the Earth at various spatio-temporal scales, inducing crustal and mantelic stress perturbations that may play a role in earthquake triggering.Deformation of the Earth by this surface loading is observed in GNSS position time series. While various models predict well vertical observations, explaining horizontal displacements remains challenging. We model the elastic deformation induced by loading derived from GRACE for coefficients 2 and higher. We estimate the degree-1 deformation field by comparison between predictions of our model and IGS-repro2 solutions at a globally distributed network of 700 GNSS sites, separating the horizontal and vertical components to avoid biases between components. The misfit between model and data is reduced compared to previous studies, particularly on the horizontal component. The associated geocenter motion time series are consistent with results derived from other datasets. We also discuss the impact on our results of systematic errors in GNSS geodetic products, in particular of the draconitic error.We then compute stress tensors time series induced by GRACE loads and discuss the potential link between large scale seasonal mass redistributions and seismicity. Within the crust, we estimate hydrologically induced stresses in the intraplate New Madrid Seismic Zone, where secular stressing rates are unmeasurably low. We show that a significant variation in the rate of micro-earthquakes at annual and multi-annual timescales coincides with stresses induced by hydrological loading in the upper Mississippi embayment, with no significant phase-lag, directly modulating regional seismicity. We also investigate pressure variations in the mantle transition zone and discuss potential correlations between the statistically significant observed seasonality of deep-focus earthquakes, most likely due to mineralogical transformations, and surface hydrological loading.

  5. Vivienda unifamiliar, en Majadahonda (Madrid

    Directory of Open Access Journals (Sweden)

    Lamela, Antonio

    1965-11-01

    Full Text Available This house is designed in accordance with the modern practice of separating the building into zones, and suitable separation and connection the various functional sectors. The solution is noteworthy because of the simplicity and clarity of design. An attempt has been made to integrate as far as as possible the garden, the porch and the internal part of the building. Also, the servant's bedroom has a triple function: it serves as ironing room, and also as dining room for the children and the servant. This house is modern, and highly authentic in its overall quality.La distribución interior de esta vivienda unifamiliar, que se diseñó siguiendo los conceptos actuales de zonificacion, y de un adecuado aislamiento y conexión entre las distintas zonas creadas, destaca por su claridad y sencillez. Señalamos asimismo que, en todo lo posible, se ha procurado introducir el jardín en el porche y la vivienda, y que el dormitorio de servicio tenga un triple uso: dormitorio, cuarto de plancha y comedor de servicio y niños. Su arquitectura es simple y actual, plena de autenticidad.

  6. Seismic anisotropy of the lithosphere around the Trans-European Suture Zone (TESZ) based on teleseismic body-wave data of the TOR experiment

    Czech Academy of Sciences Publication Activity Database

    Plomerová, Jaroslava; Babuška, Vladislav; Vecsey, Luděk; Kouba, Daniel

    2002-01-01

    Roč. 360, 1/4 (2002), s. 89-114 ISSN 0040-1951 R&D Projects: GA AV ČR IAA3012908; GA ČR GV205/98/K004 Institutional research plan: CEZ:AV0Z3012916 Keywords : shear-wave splitting * seismic anisotropy * subcrustal lithosphere Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.409, year: 2002

  7. Determination of Seismic Safety Zones during the Surface Mining Operation Development in the Case of the “Buvač” Open Pit

    OpenAIRE

    Vladimir Malbasic; Lazar Stojanovic

    2018-01-01

    Determination of the blasting safety area is a very important step in the process of drilling and blasting works, and the preparation of solid rock materials for loading. Through monitoring and analysis of the negative seismic effects to the objects and infrastructures around and at the mine area, we were able to adapt the drilling and blasting parameters and organization of drilling and blasting operation according to the mining progress so that the affected infrastructures could be protecte...

  8. Using Seismic Interferometry to Investigate Seismic Swarms

    Science.gov (United States)

    Matzel, E.; Morency, C.; Templeton, D. C.

    2017-12-01

    Seismicity provides a direct means of measuring the physical characteristics of active tectonic features such as fault zones. Hundreds of small earthquakes often occur along a fault during a seismic swarm. This seismicity helps define the tectonically active region. When processed using novel geophysical techniques, we can isolate the energy sensitive to the fault, itself. Here we focus on two methods of seismic interferometry, ambient noise correlation (ANC) and the virtual seismometer method (VSM). ANC is based on the observation that the Earth's background noise includes coherent energy, which can be recovered by observing over long time periods and allowing the incoherent energy to cancel out. The cross correlation of ambient noise between a pair of stations results in a waveform that is identical to the seismogram that would result if an impulsive source located at one of the stations was recorded at the other, the Green function (GF). The calculation of the GF is often stable after a few weeks of continuous data correlation, any perturbations to the GF after that point are directly related to changes in the subsurface and can be used for 4D monitoring.VSM is a style of seismic interferometry that provides fast, precise, high frequency estimates of the Green's function (GF) between earthquakes. VSM illuminates the subsurface precisely where the pressures are changing and has the potential to image the evolution of seismicity over time, including changes in the style of faulting. With hundreds of earthquakes, we can calculate thousands of waveforms. At the same time, VSM collapses the computational domain, often by 2-3 orders of magnitude. This allows us to do high frequency 3D modeling in the fault region. Using data from a swarm of earthquakes near the Salton Sea, we demonstrate the power of these techniques, illustrating our ability to scale from the far field, where sources are well separated, to the near field where their locations fall within each other

  9. Modeling of fault activation and seismicity by injection directly into a fault zone associated with hydraulic fracturing of shale-gas reservoirs

    Science.gov (United States)

    LBNL, in consultation with the EPA, expanded upon a previous study by injecting directly into a 3D representation of a hypothetical fault zone located in the geologic units between the shale-gas reservoir and the drinking water aquifer.

  10. Seismic Ecology

    Science.gov (United States)

    Seleznev, V. S.; Soloviev, V. M.; Emanov, A. F.

    The paper is devoted to researches of influence of seismic actions for industrial and civil buildings and people. The seismic actions bring influence directly on the people (vibration actions, force shocks at earthquakes) or indirectly through various build- ings and the constructions and can be strong (be felt by people) and weak (be fixed by sensing devices). The great number of work is devoted to influence of violent seismic actions (first of all of earthquakes) on people and various constructions. This work is devoted to study weak, but long seismic actions on various buildings and people. There is a need to take into account seismic oscillations, acting on the territory, at construction of various buildings on urbanized territories. Essential influence, except for violent earthquakes, man-caused seismic actions: the explosions, seismic noise, emitted by plant facilities and moving transport, radiation from high-rise buildings and constructions under action of a wind, etc. can exert. Materials on increase of man- caused seismicity in a number of regions in Russia, which earlier were not seismic, are presented in the paper. Along with maps of seismic microzoning maps to be built indicating a variation of amplitude spectra of seismic noise within day, months, years. The presence of an information about amplitudes and frequencies of oscillations from possible earthquakes and man-caused oscillations in concrete regions allows carry- ing out soundly designing and construction of industrial and civil housing projects. The construction of buildings even in not seismically dangerous regions, which have one from resonance frequencies coincident on magnitude to frequency of oscillations, emitted in this place by man-caused objects, can end in failure of these buildings and heaviest consequences for the people. The practical examples of detail of engineering- seismological investigation of large industrial and civil housing projects of Siberia territory (hydro power

  11. Estacionamientos subterráneos, en Madrid

    Directory of Open Access Journals (Sweden)

    López Saiz, J. M.

    1969-02-01

    Full Text Available Work on five underground parking sites in Madrid was initiated in September 1967. These parking sites were rented by the Madrid Town Council to the firm Estacionamientos Subterráneos, S. A. The engineering, design, and traffic and construction planning of these parking sites was allocated to Viales y Estacionamientos, S. A., whilst the actual construction was carried out by the firm Huarte y Cía., S. A. The five parking sites were located at the Paseo Calvo Sotelo, Plaza del Marqués de Salamanca, Plaza Mayor, Plaza de las Cortes and at Calle de Fuencarral, all within the centre of Madrid. These projects are of special interest, since each design represents an advance with respect to the earlier ones in regard to their structural and functional arrangements, with a view to achieving easier construction and less interference with road and pedestrian traffic. In the present article a description is given of each the five parking sites, following the sequence of their construction, which corresponds to the order in which they were design and planned.En septiembre de 1967 comenzaron las obras de cinco estacionamientos subterráneos en Madrid, adjudicadas por el Ayuntamiento en régimen de concesión a Estacionamientos Subterráneos, S. A. Los trabajos de ingeniería de tráfico, proyecto y control fueron encomendados a Viales y Estacionamientos, Sociedad Anteima (VIESA, y la ejecución de las obras se contrató con Huarte y Cía., S. A. Las ubicaciones de los estacionamientos cuya realización se comenta en este artículo son: Paseo de Calvo Sotelo, Plaza del Marqués de Salamanca - Plaza Mayor - Plaza de las Cortes - Calle de Fuencarral. Nos parece muy interesante exponer estas realizaciones, en las que se ve una clara evolución en su esquema estructural y la relación de éste con el esquema funcional, para lograr una mayor facilidad en la ejecución de las obras, junto con una interferencia mínima en superficie con los tráficos rodado y de

  12. The hydrogen refuelling plant in Madrid

    Energy Technology Data Exchange (ETDEWEB)

    Giron, E.; Saez, A.; Julia, A.

    2005-07-01

    Since the late days of spring 2003, a hydrogen refuelling station is operating in Madrid to provide fuel to a set of four FC-buses running in the frame of the European demonstration projects CUTE and CITYCELLS. This station is located at one of the EMT(1) bus depot premises. The station was designed and built for the EMT by the consortium 'esH2' composed by the industrial gases manufacturer Air Liquide Espana, the energy utility Gas Natural SDG and the oil company Repsol YPF. (Author)

  13. Ruta Geomonumental por Manzanares el Real (Madrid)

    OpenAIRE

    Freire-Lista, David M.; Fort, Rafael; Varas Muriel, María José

    2017-01-01

    Manzanares el Real tiene un amplio patrimonio geológico. Está ubicado en el Parque Natural de la Sierra de Guadarrama (Madrid) y sus características geológicas y monumentales posibilitan acciones de divulgación científica. Las Rutas Geomonumentales tienen como objetivo principal mostrar a la sociedad el patrimonio cultural, dándole un uso turístico y didáctico. Estas rutas combinan valores arquitectónicos e históricos con la geología y la conservación del patrimonio. El granito es la piedra d...

  14. Summary report of MINSIS workshop in Madrid

    CERN Document Server

    Alonso, Rodrigo; Blennow, Mattias; Coloma, Pilar; de Gouvea, Andre; Fernandez-Martinez, Enrique; Gavela, Belen; Gonzalez-Garcia, Concha; Hortner, Sergio; Laveder, Marco; Li, Tracey; Lopez-Pavon, Jacobo; Maltoni, Michele; Mena, Olga; Migliozzi, Pasquale; Ota, Toshihiko; Ruiz, Sergio Palomares; Para, Adam; Parke, Stephen J; Rius, Nuria; Schwetz-Mangold, Thomas; Soler, F J P; Sorel, Michel; Yasuda, Osamu; Winter, Walter

    2010-01-01

    Recent developments on tau detection technologies and the construction of high intensity neutrino beams open the possibility of a high precision search for non-standard {\\mu} - {\\tau} flavour transition with neutrinos at short distances. The MINSIS - Main Injector Non-Standard Interaction Search- is a proposal under discussion to realize such precision measurement. This document contains the proceedings of the workshop which took place on 10-11 December 2009 in Madrid to discuss both the physics reach as well as the experimental requirements for this proposal.

  15. Probabilistic Seismic Hazard Analysis for Yemen

    Directory of Open Access Journals (Sweden)

    Rakesh Mohindra

    2012-01-01

    Full Text Available A stochastic-event probabilistic seismic hazard model, which can be used further for estimates of seismic loss and seismic risk analysis, has been developed for the territory of Yemen. An updated composite earthquake catalogue has been compiled using the databases from two basic sources and several research publications. The spatial distribution of earthquakes from the catalogue was used to define and characterize the regional earthquake source zones for Yemen. To capture all possible scenarios in the seismic hazard model, a stochastic event set has been created consisting of 15,986 events generated from 1,583 fault segments in the delineated seismic source zones. Distribution of horizontal peak ground acceleration (PGA was calculated for all stochastic events considering epistemic uncertainty in ground-motion modeling using three suitable ground motion-prediction relationships, which were applied with equal weight. The probabilistic seismic hazard maps were created showing PGA and MSK seismic intensity at 10% and 50% probability of exceedance in 50 years, considering local soil site conditions. The resulting PGA for 10% probability of exceedance in 50 years (return period 475 years ranges from 0.2 g to 0.3 g in western Yemen and generally is less than 0.05 g across central and eastern Yemen. The largest contributors to Yemen’s seismic hazard are the events from the West Arabian Shield seismic zone.

  16. Evaluation of seismic damage to bridges and highway systems in Shelby County, Tennessee

    Science.gov (United States)

    Jernigan, John Bailey

    Past earthquakes have demonstrated that bridges are one of the most vulnerable components of highway transportation systems. In addition to bridges, roadways may also be subject to damage, particularly in an area prone to earthquake-induced liquefaction. As a consequence, the highway transportation systems after an earthquake might be impaired and the post-earthquake emergency response might be compromised. Furthermore, the impact on the regional economy might be very significant from the damage to highway systems. Since highway transportation systems are critical lifelines for people living in an urban area, it is important to evaluate the vulnerability of bridges and highway systems in earthquake-prone regions. Memphis and Shelby County, Tennessee are located close to the southwestern segment of the New Madrid seismic zone (NMSZ). This zone produced three of the largest earthquakes in North America in 1811--1812. Presently, the NMSZ is still active and is considered by engineers, seismologists, and public officials as the most hazardous seismic zone in the central and eastern United States. Bridges in the Memphis area were generally not designed for seismic resistance until 1990. Therefore, the majority of existing bridges might suffer damage from earthquakes occurring in the NMSZ. The overall objective of this study is to evaluate the expected damage to bridges and roadways on the major routes in Memphis and Shelby County resulting from New Madrid earthquakes with the aid of geographic information system (GIS) technology. The road network selected for this study includes all the Interstate highway system, all the primary and secondary routes maintained by the state, and most of the major arterial routes. There are 452 bridges on the selected roadway systems and data pertinent to these bridges and roadway systems were collected and implemented as a GIS database. The bridges in the Memphis area were classified into several types and damage states were determined

  17. Structure of the Kasbah fold zone (Agadir bay, Morocco). Implications on the chronology of the recent tectonics of the western High Atlas and on the seismic hazard of the Agadir area

    Energy Technology Data Exchange (ETDEWEB)

    Mridekh, A.; Medina, F.; Mhammdi, N.; Samaka, F.; Bouatmani, R.

    2009-07-01

    Detailed re-interpretation of the north-eastern segment of a profile realized across the Agadir bay along a NE-SW trend and crosscutting the main structures, together with analysis of available isochron maps, allowed us to retrace the geological history of the offshore western High Atlas. Two tectonostratigraphic sequences were distinguished: Unit II, which displays a simple structure, laying un conformably on Unit I, with a more complex structure dominated by a reverse fault (F1) striking E-W with a dip to the north. Correlation to boreholes Souss-1 and AGM-1 allowed us to assign Unit I to the Triassic Palaeogene and Unit II to the Miocene Present. The NE fault block shows a ramp-flat fault plane (F2) with an overlying SW-vergent fold that can be interpreted as a fault-bend fold. Three main stages were distinguished: (1) during the Cretaceous, F1 could have been a syn depositional normal fault with the NE block moving downwards; (2) towards the beginning of the Tertiary, the displacement of plane F2 induced the development of a fault-bend fold and erosion of the forelimb and hinge of the fold; displacement along F2 was transferred to fault F1; (3) afterwards, during the Miocene, reverse motion of F1 deformed and tilted the plane F2 and accentuated the folded structure. This evolution is typical for a frontal basin above a fault-related fold. Evaluation of the thickness and bed depth differences shows that the largest growth rate was recorded in Late Miocene times. Seismic activity recorded in the Agadir bay appears to be clearly related to this fault zone, as inferred from focal mechanisms. Seismic moment evaluation suggests that earthquakes of magnitude Mw=6 are likely to occur, but could not be much larger because of the fault segmentation geometry of the High Atlas Front. (Author) 53 refs.

  18. Dominant seismic sources for the cities in South Sumatra

    Science.gov (United States)

    Sunardi, Bambang; Sakya, Andi Eka; Masturyono, Murjaya, Jaya; Rohadi, Supriyanto; Sulastri, Putra, Ade Surya

    2017-07-01

    Subduction zone along west of Sumatra and Sumatran fault zone are active seismic sources. Seismotectonically, South Sumatra could be affected by earthquakes triggered by these seismic sources. This paper discussed contribution of each seismic source to earthquake hazards for cities of Palembang, Prabumulih, Banyuasin, OganIlir, Ogan Komering Ilir, South Oku, Musi Rawas and Empat Lawang. These hazards are presented in form of seismic hazard curves. The study was conducted by using Probabilistic Seismic Hazard Analysis (PSHA) of 2% probability of exceedance in 50 years. Seismic sources used in analysis included megathrust zone M2 of Sumatra and South Sumatra, background seismic sources and shallow crustal seismic sources consist of Ketaun, Musi, Manna and Kumering faults. The results of the study showed that for cities relatively far from the seismic sources, subduction / megathrust seismic source with a depth ≤ 50 km greatly contributed to the seismic hazard and the other areas showed deep background seismic sources with a depth of more than 100 km dominate to seismic hazard respectively.

  19. De Madrid al cielo: La importancia de enfermar y morir en Madrid

    Directory of Open Access Journals (Sweden)

    JESÚS M. DE MIGUEL

    1988-01-01

    Full Text Available Una tasa de mortalidad por debajo del promedio nacional español ha hecho que Madrid se gane la reputación de lugar sano para vivir y para morir; aquí, se examina esta reputación usando datos empíricos recientes. Las estadísticas de población demuestran cómo durante los últimos sesenta años, Madrid ha mostrado un mayor crecimiento durante los años 60 y 70, un período de desarrollo económico; desde entonces el nivel de salud se ha deteriorado. La prosperidad económica por sí misma no asegura unas condiciones mejores de la salud, a causa de las desigualdades y desequilibrios en la distribución y el control de los recursos sanitarios. Los datos sobre tipos de enfermedades, causas de hospitalización y periodos de estancia, embarazos, muertes accidentales, y nacimientos, matrimonios, y los índices de mortalidad para Madrid se presentan, y son comparados con los de Barcelona y los de España en su totalidad. De igual modo se sugieren otras áreas de investigación.

  20. Equidad y Eficiencia del transporte público en Madrid.

    OpenAIRE

    Vassallo Magro, José Manuel; Pérez de Villar Cruz, Pablo

    2008-01-01

    La política de transporte público en la Comunidad de Madrid se ha considerado tradicionalmente un éxito. En gran parte, éste se debe a la existencia del Consorcio Regional de Transportes. Sin embargo, el sistema de transporte público de Madrid recibe subvenciones cada vez mayores, lo que supone una amenaza a la viabilidad del modelo en el futuro. Este artículo analiza la evolución de la política de financiación del sistema de transporte público en Madrid en los últimos años. Del análisis llev...

  1. Study of the superficial ozone concentrations in the atmosphere of Comunidad de Madrid using passive samplers

    Directory of Open Access Journals (Sweden)

    D. Galán Madruga

    2001-06-01

    Full Text Available The ozone is a secondary atmospheric pollutant which is generated for photochemical reactions of volatil organic compounds (VOC’s and nitrogen oxides (NOx. In Spain the ozone is a big problem as a consequence of the solar radiation to reach high levels. Exposure over a period of time to elevated ozone concentrations can cause damage in the public health and alterations in the vegetation.The aim of this study is to carry out the development and validation of a measurement method to let asses the superficial ozone levels in the Comunidad de Madrid, by identifing the zones more significants, where to measure with UV photometric monitors (automatics methods this pollutant and where the health and the vegetation can be affected. To such effect, passive samplers are used, which have glass fiber filters coated with a solution of sodium nitrite, potassium carbonate, glycerol and water. The nitrite ion in the presence of ozone is oxidized to nitrato ion, which it is extrated with ultrapure water and analyzed for ion chromatography, by seen proportional to the concentration existing in the sampling point.The results of validation from field tests indicate a excellent correlation between the passive and the automatic method.The higher superficial ozone concentrations are placed in rural zones, distanced of emission focus of primary pollutants (nitrogen oxides and volatil organic compounds... principally in direction soutwest and northwest of the Comunidad of Madrid.

  2. Interchanges genesis Plan of Madrid = Génesis del plan de intercambiadores de Madrid

    Directory of Open Access Journals (Sweden)

    Javier Aldecoa Martínez-Conde

    2018-04-01

    Full Text Available The public transport, as we know it today, originates from the end of the 18 th and beginning of the 19th Centuries. Initially a privilege for the aristocratic and bourgeoisie classes, public transport saw a surge in development once communication between Madrid and others distant urban centers became a necessity that demanded a more economical and accessible transport system. The increase of these services, along with the diversification of the means of transportation, quickly caused congestion problems at transfer points. Throughout the last century, these same problems have been confronted with a variety of diverse strategies and solutions. All in all, the history of intermodality in Madrid tells the story of an evolution that has allowed the urban web to unite all of its branches extending from the main gates that are now being converted the interchanges in relation with the city. From its creation in 1985, the CRTM (transport authority of Madrid, considered the intermodality to be a main priority within the following different fields of action: infrastructure, ticketing and whole image and information. Within the interchanges is where the integration efforts of the different transport modes best become a reality. In essence, interchanges play the same role in today`s cities as the gates in the walls of a centuries-old medieval city. At this moment, interchanges are the gates to the cities of the 21st Century. Resumen El transporte público, tal como lo conocemos hoy, se origina a finales del siglo XVIII y principios del XIX. Inicialmente fue un privilegio para las clases aristocráticas y burguesas. El transporte público vio un aumento en el desarrollo una vez que la comunicación entre Madrid y otros centros urbanos distantes se convirtió en una necesidad que exigía un sistema de transporte más económico y accesible. El aumento de estos servicios, junto con la diversificación de los medios de transporte, causó rápidamente problemas

  3. Progressive Seismic Failure, Seismic Gap, and Great Seismic Risk across the Densely Populated North China Basin

    Science.gov (United States)

    Yin, A.; Yu, X.; Shen, Z.

    2014-12-01

    Although the seismically active North China basin has the most complete written records of pre-instrumentation earthquakes in the world, this information has not been fully utilized for assessing potential earthquake hazards of this densely populated region that hosts ~200 million people. In this study, we use the historical records to document the earthquake migration pattern and the existence of a 180-km seismic gap along the 600-km long right-slip Tangshan-Hejian-Cixian (THC) fault zone that cuts across the North China basin. The newly recognized seismic gap, which is centered at Tianjin with a population of 11 million people and ~120 km from Beijing (22 million people) and Tangshan (7 million people), has not been ruptured in the past 1000 years by M≥6 earthquakes. The seismic migration pattern in the past millennium suggests that the epicenters of major earthquakes have shifted towards this seismic gap along the THC fault, which implies that the 180- km gap could be the site of the next great earthquake with M≈7.6 if it is ruptured by a single event. Alternatively, the seismic gap may be explained by aseismic creeping or seismic strain transfer between active faults.

  4. Estación de Chamartín Madrid – España

    Directory of Open Access Journals (Sweden)

    López Astorga, Roberto

    1976-11-01

    Full Text Available This group of constructions which constitutes the final phase in the Chamartín railway station, situated in the northern part of Madrid, consist of: — A 18,250 m2 local train station which comprises halls, cafeterias, shops, luggage room, offices of Zone 1 of the Renfe and various other service installations. - A building for goods and sleeping carriages with storage department, customs, etc., and 7,025 m2 of usable area. — A 71,380 m2 long distance station with similar, although more ample services to those of the local train station; moreover, it is provided with a covered parking site and various complementary installation. — A 24,670 m2 hotel with a capacity of 210 rooms, distributed over five storeys, to which 4 more storeys can be added, whereby the capacity would be increased to 378 rooms. — A thermic central of 5,810 m2 contains all the installations required for this group of buildings. The complex is completed by service corridors for luggage and goods, parking places, connecting pedestrian crossing, and a complete road system with roads both at ground level as well as overhead and underground; a theatre and a big pedestrian square that forms the focus and connecting element between all the buildings. The design of the complex was determined according to the following factors: — Integration with the city: By means of the open arrangement of the various constructions towards the city and by the big pedestrian square that constitutes an efficient link with the adjoinining zones. — Connection with the city: Direct access to two main highways and several means of public transport, such as: underground station parallel to the platforms; bus lines with a stop at the entrance of the terminal; taxi station, etc. — Separation of the traffic within the complex from the city traffic: By means of traffic ways at different levels. — Maximum use of already constructed parts: By utilizing already finished works

  5. Imported malaria in pregnancy in Madrid

    Directory of Open Access Journals (Sweden)

    Jiménez Beatriz C

    2012-04-01

    Full Text Available Abstract Background Malaria in pregnancy is associated with maternal and foetal morbidity and mortality in endemic areas, but information on imported cases to non-endemic areas is scarce. The aim of this study was to describe the clinical and epidemiological characteristics of malaria in pregnancy in two general hospitals in Madrid, Spain. Methods Retrospective descriptive study of laboratory-confirmed malaria in pregnant women at the Fuenlabrada University Hospital and the Príncipe de Asturias University Hospital, in Madrid, over a six- and 11-year period, respectively. Relevant epidemiological, clinical and laboratory data was obtained from medical records. Results There were 19 pregnant women among 346 malaria cases (5.4%. The average age was 27 years. The gestational age (trimester was: 53% 3rd, 31% 1st, 16% 2nd. All but one were multigravidae. Three were HIV positive. All were sub-Saharan immigrants: two were recently arrived immigrants and seventeen (89% had visited friends and relatives. None had taken prophylaxis nor seeked pre-travel advice. Presentation: 16 symptomatic patients (fever in fourteen, asthenia in two, three asymptomatic. Median delay in diagnosis: 7.5 days. Laboratory tests: anaemia (cut off Hb level 11 g/dl 78.9% (mild 31.6%, moderate 31.6%, severe 15.8% thrombocytopaenia 73.7%, hypoglycaemia 10.5%. All cases were due to Plasmodium falciparum, one case of hyperparasitaemia. Quinine + clindamycin prescribed in 84%. Outcomes: no severe maternal complications or deaths, two abortions, fifteen term pregnancies, no low-birth-weight newborns, two patients were lost to follow-up. Conclusions Though cases of malaria in pregnancy are uncommon, a most at risk group is clearly defined: young sub-Saharan mothers visiting friends and relatives without pre-travel counselling and recently-arrived immigrants. The most common adverse maternal and foetal effects were anaemia and stillbirth. Given that presentation can be asymptomatic

  6. Causality between expansion of seismic cloud and maximum magnitude of induced seismicity in geothermal field

    Science.gov (United States)

    Mukuhira, Yusuke; Asanuma, Hiroshi; Ito, Takatoshi; Häring, Markus

    2016-04-01

    Occurrence of induced seismicity with large magnitude is critical environmental issues associated with fluid injection for shale gas/oil extraction, waste water disposal, carbon capture and storage, and engineered geothermal systems (EGS). Studies for prediction of the hazardous seismicity and risk assessment of induced seismicity has been activated recently. Many of these studies are based on the seismological statistics and these models use the information of the occurrence time and event magnitude. We have originally developed physics based model named "possible seismic moment model" to evaluate seismic activity and assess seismic moment which can be ready to release. This model is totally based on microseismic information of occurrence time, hypocenter location and magnitude (seismic moment). This model assumes existence of representative parameter having physical meaning that release-able seismic moment per rock volume (seismic moment density) at given field. Seismic moment density is to be estimated from microseismic distribution and their seismic moment. In addition to this, stimulated rock volume is also inferred by progress of microseismic cloud at given time and this quantity can be interpreted as the rock volume which can release seismic energy due to weakening effect of normal stress by injected fluid. Product of these two parameters (equation (1)) provide possible seismic moment which can be released from current stimulated zone as a model output. Difference between output of this model and observed cumulative seismic moment corresponds the seismic moment which will be released in future, based on current stimulation conditions. This value can be translated into possible maximum magnitude of induced seismicity in future. As this way, possible seismic moment can be used to have feedback to hydraulic stimulation operation in real time as an index which can be interpreted easily and intuitively. Possible seismic moment is defined as equation (1), where D

  7. Seismic Studies

    Energy Technology Data Exchange (ETDEWEB)

    R. Quittmeyer

    2006-09-25

    This technical work plan (TWP) describes the efforts to develop and confirm seismic ground motion inputs used for preclosure design and probabilistic safety 'analyses and to assess the postclosure performance of a repository at Yucca Mountain, Nevada. As part of the effort to develop seismic inputs, the TWP covers testing and analyses that provide the technical basis for inputs to the seismic ground-motion site-response model. The TWP also addresses preparation of a seismic methodology report for submission to the U.S. Nuclear Regulatory Commission (NRC). The activities discussed in this TWP are planned for fiscal years (FY) 2006 through 2008. Some of the work enhances the technical basis for previously developed seismic inputs and reduces uncertainties and conservatism used in previous analyses and modeling. These activities support the defense of a license application. Other activities provide new results that will support development of the preclosure, safety case; these results directly support and will be included in the license application. Table 1 indicates which activities support the license application and which support licensing defense. The activities are listed in Section 1.2; the methods and approaches used to implement them are discussed in more detail in Section 2.2. Technical and performance objectives of this work scope are: (1) For annual ground motion exceedance probabilities appropriate for preclosure design analyses, provide site-specific seismic design acceleration response spectra for a range of damping values; strain-compatible soil properties; peak motions, strains, and curvatures as a function of depth; and time histories (acceleration, velocity, and displacement). Provide seismic design inputs for the waste emplacement level and for surface sites. Results should be consistent with the probabilistic seismic hazard analysis (PSHA) for Yucca Mountain and reflect, as appropriate, available knowledge on the limits to extreme ground

  8. Seismic Studies

    International Nuclear Information System (INIS)

    R. Quittmeyer

    2006-01-01

    This technical work plan (TWP) describes the efforts to develop and confirm seismic ground motion inputs used for preclosure design and probabilistic safety 'analyses and to assess the postclosure performance of a repository at Yucca Mountain, Nevada. As part of the effort to develop seismic inputs, the TWP covers testing and analyses that provide the technical basis for inputs to the seismic ground-motion site-response model. The TWP also addresses preparation of a seismic methodology report for submission to the U.S. Nuclear Regulatory Commission (NRC). The activities discussed in this TWP are planned for fiscal years (FY) 2006 through 2008. Some of the work enhances the technical basis for previously developed seismic inputs and reduces uncertainties and conservatism used in previous analyses and modeling. These activities support the defense of a license application. Other activities provide new results that will support development of the preclosure, safety case; these results directly support and will be included in the license application. Table 1 indicates which activities support the license application and which support licensing defense. The activities are listed in Section 1.2; the methods and approaches used to implement them are discussed in more detail in Section 2.2. Technical and performance objectives of this work scope are: (1) For annual ground motion exceedance probabilities appropriate for preclosure design analyses, provide site-specific seismic design acceleration response spectra for a range of damping values; strain-compatible soil properties; peak motions, strains, and curvatures as a function of depth; and time histories (acceleration, velocity, and displacement). Provide seismic design inputs for the waste emplacement level and for surface sites. Results should be consistent with the probabilistic seismic hazard analysis (PSHA) for Yucca Mountain and reflect, as appropriate, available knowledge on the limits to extreme ground motion at

  9. Seismic protection

    International Nuclear Information System (INIS)

    Herbert, R.

    1988-01-01

    To ensure that a nuclear reactor or other damage-susceptible installation is, so far as possible, tripped and already shut down before the arrival of an earthquake shock at its location, a ring of monitoring seismic sensors is provided around it, each sensor being spaced from it by a distance (possibly several kilometres) such that (taking into account the seismic-shock propagation velocity through the intervening ground) a shock monitored by the sensor and then advancing to the installation site will arrive there later than a warning signal emitted by the sensor and received at the installation, by an interval sufficient to allow the installation to trip and shut down, or otherwise assume an optimum anti-seismic mode, in response to the warning signal. Extra sensors located in boreholes may define effectively a three-dimensional (hemispherical) sensing boundary rather than a mere two-dimensional ring. (author)

  10. Induced Seismicity

    Science.gov (United States)

    Keranen, Katie M.; Weingarten, Matthew

    2018-05-01

    The ability of fluid-generated subsurface stress changes to trigger earthquakes has long been recognized. However, the dramatic rise in the rate of human-induced earthquakes in the past decade has created abundant opportunities to study induced earthquakes and triggering processes. This review briefly summarizes early studies but focuses on results from induced earthquakes during the past 10 years related to fluid injection in petroleum fields. Study of these earthquakes has resulted in insights into physical processes and has identified knowledge gaps and future research directions. Induced earthquakes are challenging to identify using seismological methods, and faults and reefs strongly modulate spatial and temporal patterns of induced seismicity. However, the similarity of induced and natural seismicity provides an effective tool for studying earthquake processes. With continuing development of energy resources, increased interest in carbon sequestration, and construction of large dams, induced seismicity will continue to pose a hazard in coming years.

  11. Edificio del Ilustre Colegio de Registradores de la Propiedad, en Madrid, España

    Directory of Open Access Journals (Sweden)

    Azpiazu Ordóñez, J. R.

    1966-05-01

    Full Text Available This building has a basement, ground floor, seven additional floors, and an attic. The basement is occupied by the heating and air conditioning installations, the electricity meters the archive of the registrars, and houses for the doorman and porter. On the ground floor there is an information and doorman's booth, a map of Spain with the zones covered by each registrar, the hall, lifts, stairs, whilst the rest of the floor is devoted to commercial activities. The first floor belongs to the Registrars' College, and the 2nd, 3rd, 4th, 5th and 6th floors have been allocated to the offices of all the property registrars of Madrid. The 7th floor and the attic are offices, to be let to outsiders.El edificio consta de: sótano, planta baja, siete plantas de altura, y planta de ático. El sótano alberga los servicios de: calefacción y refrigeración, cuarto de contadores, archivo de legajos de Registros, viviendas del portero y conserje, etc. En la planta baja se encuentran: la cabina de información y estancia del portero, el mapa de Madrid con la demarcación de Registros, el hall de ascensores y escalera, etc.; el resto de la planta está ocupado por eventuales locales comerciales. La planta primera está destinada a sede del Ilustre Colegio de Registradores de la Propiedad; las plantas segunda, tercera, cuarta, quinta y sexta se han reservado para instalar todos los Registros de Madrid; y las plantas séptima y de ático se han destinado para oficinas de alquiler.

  12. Antonio Ricci en Madrid: 1586-1635

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    García López, David

    2010-03-01

    Full Text Available Life of painter Antonio Ricci is studied by new documents from his arrived at Escorial with Federico Zuccari in 1586. Ricci worked in the Palace of Madrid and was involved in the birth of the Academy of Painting. Here are studied his work as Painter and Appraiser, or his portrait of Philip IV of Spain and his relationship with Jeronimo Gratti, Caballero de Gracia.

    Nuevas aportaciones documentales aclaran la vida del pintor Antonio Ricci en la Corte española desde su llegada a El Escorial junto a Federico Zuccari en 1586. Ricci trabajó como pintor en el entorno palaciego y estuvo involucrado desde el principio en el intento de creación de la Academia madrileña de pintores. Se detallan aquí su trabajo como tasador, su retrato del futuro Felipe IV o su cercana relación con un personaje tan singular como Jeronimo Gratti, el Caballero de Gracia.

  13. Seismic gaps and plate tectonics: seismic potential for major boundaries

    Energy Technology Data Exchange (ETDEWEB)

    McCann, W R; Nishenko, S P; Sykes, L R; Krause, J

    1979-01-01

    The theory of plate tectonics provides a basic framework for evaluating the potential for future great earthquakes to occur along major plate boundaries. Along most of the transform and convergent plate boundaries considered in this paper, the majority of seismic slip occurs during large earthquakes, i.e., those of magnitude 7 or greater. The concepts that rupture zones, as delineated by aftershocks, tend to abut rather than overlap, and large events occur in regions with histories of both long-and short-term seismic quiescence are used in this paper to delineate major seismic gaps. The term seismic gap is taken to refer to any region along an active plate boundary that has not experienced a large thrust or strike-slip earthquake for more than 30 years. A region of high seismic potential is a seismic gap that, for historic or tectonic reasons, is considered likely to produce a large shock during the next few decades. The seismic gap technique provides estimates of the location, size of future events and origin time to within a few tens of years at best. The accompanying map summarizes six categories of seismic potential for major plate boundaries in and around the margins of the Pacific Ocean and the Caribbean, South Sandwich and Sunda (Indonesia) regions for the next few decades. These six categories are meant to be interpreted as forecasts of the location and size of future large shocks and should not be considered to be predictions in which a precise estimate of the time of occurrence is specified. The categories of potential assigned here provide a rationale for assigning priorities for instrumentation, for future studies aimed at predicting large earthquakes and for making estimates of tsunami potential.

  14. El Abasto de Pan en el Madrid del Siglo XVII Bread provision in seventeenth century Madrid

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    José Ignacio ANDRÉS UCENDO

    2012-12-01

    Full Text Available El mercado del pan era el más importante de los mercados de abastos, pero también el que contaba con el más complejo sistema de intervención. Los objetivos de la política de abastos eran asegurar un suministro continuo a precios estables y moderados.Los instrumentos incluían la regulación de los precios del grano y el pan, la provisión directa a través del pósito municipal y, en el caso de la corte, el pan de registro. En este trabajo examinamos la política de tasas, las disposiciones del gobierno y el comportamiento de los precios del pan en Madrid y del trigo en los mercados de origen.Bread market was the most important provision markets, so the complexity of intervention system. The aim of provision policy was to guarantee the continuous supply of bread at moderate and stable prices. The means included the regulation the price, the direct provision by the public granary and, in the case of the court, the named registered bread. This paper examines the tax policy, the government requirements and the movement of bread prices in Madrid and wheat prices in the markets of origin.

  15. PARAMETERS OF KAMCHATKA SEISMICITY IN 2008

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    Vadim A. Saltykov

    2010-01-01

    estimations give evidence that the year of 2008 was not anomalous in terms of seismicity. Based on 2D distribution of recurrence graph slope γ, it is possible to locate an area of lower values of γ in the southern part of the Kamchatka seismic zone (Fig. 4. Data on maps of normalized variation of γ for 2007–2008 and 2006–2008 (Fig. 5 confirm statistical importance of γ reduction through the last three years in the given area. Maps of 2D distribution of seismic activity A10 are constructed for 2008 and the perdiod from 1962 to 2008; values of seismic activity A10 that are normalized to the average annual seismic activity are also mapped (Fig. 6. In 2008, increased values of A10 were observed at the southern part of the Avachinsky gulf and at the northern part of the Kamchatka gulf, as well as in the northern water area of Bering Island. The anomalous behavior of parameters RTL, ΔS and clustering of earthquakes may have predictive character [Sobolev, 2000]. Negative values of RTL-parameter correspond to seismic quiescence; increasing areas of seismic ruptures ΔS correspond to foreshock activation; clustering of earthquakes can evidence that activation tends to accumulate at a future main rupture location. For 2008, three zones of seismic quiescence were defined by data (Fig. 7. For estimation points with maximum modular values of RTL (marked by the Roman numerals in Fig. 7, RTL time curves are constructed for each of the above mentioned zones (Fig. 8; they provide for defining durations of anomalies and degrees of manifestation. A map of variations of seismic rupture areas ΔS (Fig. 9 shows that seismic activity of 2008 was mainly manifested at the southern part of the Kamchatka seismic zone. In 2008, most of the earthquake clusters varying in energy also occurred in the southern part of Kamchatka (Fig. 10. The northern chain of clusters is located at the border of the developing seismic anomaly, as defined by RTL parameter. Similar to RTL technique, an objective of

  16. Strong motion modeling at the Paducah Diffusion Facility for a large New Madrid earthquake

    International Nuclear Information System (INIS)

    Herrmann, R.B.

    1991-01-01

    The Paducah Diffusion Facility is within 80 kilometers of the location of the very large New Madrid earthquakes which occurred during the winter of 1811-1812. Because of their size, seismic moment of 2.0 x 10 27 dyne-cm or moment magnitude M w = 7.5, the possible recurrence of these earthquakes is a major element in the assessment of seismic hazard at the facility. Probabilistic hazard analysis can provide uniform hazard response spectra estimates for structure evaluation, but a deterministic modeling of a such a large earthquake can provide strong constraints on the expected duration of motion. The large earthquake is modeled by specifying the earthquake fault and its orientation with respect to the site, and by specifying the rupture process. Synthetic time histories, based on forward modeling of the wavefield, from each subelement are combined to yield a three component time history at the site. Various simulations are performed to sufficiently exercise possible spatial and temporal distributions of energy release on the fault. Preliminary results demonstrate the sensitivity of the method to various assumptions, and also indicate strongly that the total duration of ground motion at the site is controlled primarily by the length of the rupture process on the fault

  17. Seismic Symphonies

    Science.gov (United States)

    Strinna, Elisa; Ferrari, Graziano

    2015-04-01

    The project started in 2008 as a sound installation, a collaboration between an artist, a barrel organ builder and a seismologist. The work differs from other attempts of sound transposition of seismic records. In this case seismic frequencies are not converted automatically into the "sound of the earthquake." However, it has been studied a musical translation system that, based on the organ tonal scale, generates a totally unexpected sequence of sounds which is intended to evoke the emotions aroused by the earthquake. The symphonies proposed in the project have somewhat peculiar origins: they in fact come to life from the translation of graphic tracks into a sound track. The graphic tracks in question are made up by copies of seismograms recorded during some earthquakes that have taken place around the world. Seismograms are translated into music by a sculpture-instrument, half a seismograph and half a barrel organ. The organ plays through holes practiced on paper. Adapting the documents to the instrument score, holes have been drilled on the waves' peaks. The organ covers about three tonal scales, starting from heavy and deep sounds it reaches up to high and jarring notes. The translation of the seismic records is based on a criterion that does match the highest sounds to larger amplitudes with lower ones to minors. Translating the seismogram in the organ score, the larger the amplitude of recorded waves, the more the seismogram covers the full tonal scale played by the barrel organ and the notes arouse an intense emotional response in the listener. Elisa Strinna's Seismic Symphonies installation becomes an unprecedented tool for emotional involvement, through which can be revived the memory of the greatest disasters of over a century of seismic history of the Earth. A bridge between art and science. Seismic Symphonies is also a symbolic inversion: the instrument of the organ is most commonly used in churches, and its sounds are derived from the heavens and

  18. SHC, Seismic Hazard Assessment for Eastern US

    International Nuclear Information System (INIS)

    Savy, J.; Davis, B.

    2001-01-01

    1 - Description of program or function: SHC was developed as part of the Eastern United States (EUS) Seismic Hazard Characterization (SHC) Project to design an SHC methodology for the region east of the Rocky Mountains in a form suitable for probabilistic risk assessment and to apply that methodology to 69 site locations, some of them with local soil conditions. The method developed uses expert opinions to obtain the input to the analysis. SHC contains four modules which calculate the seismic hazard at a site located in a region of diffuse seismicity, where the seismicity is modeled by area sources. SHC integrates the opinions of 11 seismicity and five ground-motion experts. The PRDS model generates the discrete probability density function of the distances to the site for the various seismic source zones. These probability distributions are used by the COMAP module to generate the set of all alternative maps and the discrete probability density of the seismic zonation maps for each expert. The third module, ALEAS, uses these maps and their weights to calculate the best estimate and constant percentile hazard distribution resulting from the choice of a given seismicity expert for all ground-motion experts. This module can be used alone to perform a seismic hazard analysis as well as in conjunction with the other modules. The fourth module, COMB, combines the best- estimate and constant-percentile hazard over all seismicity experts, using the set of weights calculated by ALEAS, to produce the final probability distribution of the hazard for the site under consideration so that the hazard analysis can be performed for any location in the EUS. Local geological-site characteristics are incorporated in a generic fashion, and the data are developed in a generic manner. 2 - Method of solution: SHC uses a seismic-source approach utilizing statistical and geological evidence to define geographical regions with homogeneous Poisson activity throughout the zone, described by a

  19. Seismic hazard estimation based on the distributed seismicity in northern China

    Science.gov (United States)

    Yang, Yong; Shi, Bao-Ping; Sun, Liang

    2008-03-01

    In this paper, we have proposed an alternative seismic hazard modeling by using distributed seismicites. The distributed seismicity model does not need delineation of seismic source zones, and simplify the methodology of probabilistic seismic hazard analysis. Based on the devastating earthquake catalogue, we established three seismicity model, derived the distribution of a-value in northern China by using Gaussian smoothing function, and calculated peak ground acceleration distributions for this area with 2%, 5% and 10% probability of exceedance in a 50-year period by using three attenuation models, respectively. In general, the peak ground motion distribution patterns are consistent with current seismic hazard map of China, but in some specific seismic zones which include Shanxi Province and Shijiazhuang areas, our results indicated a little bit higher peak ground motions and zonation characters which are in agreement with seismicity distribution patterns in these areas. The hazard curves have been developed for Beijing, Tianjin, Taiyuan, Tangshan, and Ji’nan, the metropolitan cities in the northern China. The results showed that Tangshan, Taiyuan, Beijing has a higher seismic hazard than that of other cities mentioned above.

  20. Spectral Decomposition and Other Seismic Attributes for Gas Hydrate Prospecting

    Energy Technology Data Exchange (ETDEWEB)

    McConnell, Dan

    2018-02-25

    Studying the sediments at the base of gas hydrate stability is ideal for determining the seismic response to gas hydrate saturation. First, assuming gas migration to the shallow section, this area is more likely to have concentrated gas hydrate because it encompasses the zone in which upward moving buoyant gas transitions to form immobile gas hydrate deposits. Second, this zone is interesting because these areas have the potential to show a hydrate filled zone and a gas filled zone within the same sediments. Third, the fundamental measurement within seismic data is impedance contrasts between velocity*density layers. High saturation gas hydrates and free gas inhabit opposite ends of these measurements making the study of this zone ideal for investigating the seismic characteristics of gas hydrate and, hence, the investigation of other seismic attributes that may indicate gas hydrate fill.

  1. New Madrid seismotectonic study. Activities during fiscal year 1982

    International Nuclear Information System (INIS)

    Buschbach, T.C.

    1984-04-01

    The New Madrid Seismotectonic Study is a coordinated program of geological, geophysical, and seismological investigations of the area within a 200-mile radius of New Madrid, Missouri. The study is designed to define the structural setting and tectonic history of the area in order to realistically evaluate earthquake risks in the siting of nuclear facilities. Fiscal year 1982 included geological and geophysical studies aimed at better definition of the east-west trending fault systems - the Rough Creek and Cottage Grove systems - and the northwest-trending Ste. Genevieve faulting. A prime objective was to determine the nature and history of faulting and to establish the relationship with that faulting and the northeast-trending faults of the Wabash Valley and New Madrid areas. 27 references, 61 figures

  2. La construcción de la marca Madrid

    Directory of Open Access Journals (Sweden)

    Elia Canosa Zamora

    2012-01-01

    Full Text Available Durante los últimos veinte años, los sucesivos gobiernos de Madrid, han centrado en el posicionamiento internacional de la ciudad sus expectativas de desarrollo económico, de transformación urbana y de bienestar ciudadano. La construcción de la Marca Madrid forma parte de esta estrategia que ha terminado por convertirse en el eje director de gestión y la ordenación urbana. La relevancia de este fenómeno se analizará en tres vertientes fundamentales: valorando el significado de la opción oficial de Madrid ciudad global, planteando el ascenso de la imagen como base vertebradora de las operaciones destinadas a favorecer esta internacionalización y profundizando en el valor de la arquitectura como icono urbano.

  3. Seismic modelling of coal bed methane strata, Willow Creek, Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, S.E.; Mayer, R.; Lawton, D.C.; Langenberg, W. [Consortium for Research in Elastic Wave Exploration Seismology, Calgary, AB (Canada)

    2001-07-01

    The purpose is to determine the feasibility of applying high- resolution reflection seismic surveying to coalbed methane (CBM) exploration and development. Numerical reflection seismic methods are examined for measuring the mapping continuity and coherence of coal zones. Numerical modelling of a coal zone in Upper Cretaceous sediments near Willow Creek, Alberta indicates that seismic data that is predominantly of 100 Hz is required to map the coal zone and lateral facies variations within the deposit. For resolution of individual coal seams, a central frequency >150 Hz would be needed. 26 refs., 17 figs., 3 tabs.

  4. Seismic Discrimination

    Science.gov (United States)

    1979-09-30

    were presumed nuclear explosions announced by ERDA. Of the last, 11 were at the Semipalatinsk test site , 2 at the Western Kazakh test site , 2 in Novaya...which will fulfill U.S. ob- ligations that may be incurred under a possible future Comprehensive Test Ban Treaty. This report includes 9 contributions...which could assume U.S. seismic-data-management responsibilities in the event that international agreement is reached on a Comprehensive Test Ban

  5. Martian seismicity

    International Nuclear Information System (INIS)

    Goins, N.R.; Lazarewicz, A.R.

    1979-01-01

    During the Viking mission to Mars, the seismometer on Lander II collected approximately 0.24 Earth years of observations data, excluding periods of time dominated by wind-induced Lander vibration. The ''quiet-time'' data set contains no confirmed seismic events. A proper assessment of the significance of this fact requires quantitative estimates of the expected detection rate of the Viking seismometer. The first step is to calculate the minimum magnitude event detectable at a given distance, including the effects of geometric spreading, anelastic attenuation, seismic signal duration, seismometer frequency response, and possible poor ground coupling. Assuming various numerical quantities and a Martian seismic activity comparable to that of intraplate earthquakes, the appropriate integral gives an expected annual detection rate of 10 events, nearly all of which are local. Thus only two to three events would be expected in the observational period presently on hand and the lack of observed events is not in gross contradiction to reasonable expectations. Given the same assumptions, a seismometer 20 times more sensitive than the present instrument would be expected to detect about 120 events annually

  6. Assembly of Drift Tubes (DT) Chambers at CIEMAT (Madrid)

    CERN Multimedia

    Jesus Puerta-Pelayo

    2003-01-01

    The construction of muon drift tube chambers (DT) has been carried out in four different european institutes: Aachen (Germany), CIEMAT-Madrid (Spain), Legnaro and Turin (Italy), all of them following similar procedures and quality tests. Each chamber is composed by three or two independent units called superlayers, with four layers of staggered drift cells each. The assembly of a superlayer is a succesive glueing of aluminium plates and I-beams with electrodes previously attached, forming a rectangular and gas-tight volume. These pictures illustrate the various processes of material preparation, construction, equipment and assembly of full chambers at CIEMAT (Madrid).

  7. Madrid en el siglo XXI. Transformaciones y retos de su realidad social. La Realidad Social de Madrid Vol. II

    Directory of Open Access Journals (Sweden)

    Mª del Pilar Gomiz Pascual

    2014-03-01

    Full Text Available Madrid en el siglo XXI. Transformaciones y retos de su realidad social  es el título elegido por la Asociación Madrileña de Sociología (AMS para el segundo volumen de lo que pretende ser una trilogía sobre la Realidad Social de Madrid. Tras el éxito del trabajo realizado con el primer volumen, Antonio Lucas Marín, Carmen Cortés Beltrán y Dolores Cáceres Zapatero, vuelven a coordinar un proyecto excelente donde se da un paso más al esfuerzo comenzado con la edición anterior por dar a conocer aspectos nuevos de la estructura social del Madrid del siglo XXI, aportando enfoques y matices que quedaron sin analizar entonces. 

  8. Seismic hazard maps for Haiti

    Science.gov (United States)

    Frankel, Arthur; Harmsen, Stephen; Mueller, Charles; Calais, Eric; Haase, Jennifer

    2011-01-01

    We have produced probabilistic seismic hazard maps of Haiti for peak ground acceleration and response spectral accelerations that include the hazard from the major crustal faults, subduction zones, and background earthquakes. The hazard from the Enriquillo-Plantain Garden, Septentrional, and Matheux-Neiba fault zones was estimated using fault slip rates determined from GPS measurements. The hazard from the subduction zones along the northern and southeastern coasts of Hispaniola was calculated from slip rates derived from GPS data and the overall plate motion. Hazard maps were made for a firm-rock site condition and for a grid of shallow shear-wave velocities estimated from topographic slope. The maps show substantial hazard throughout Haiti, with the highest hazard in Haiti along the Enriquillo-Plantain Garden and Septentrional fault zones. The Matheux-Neiba Fault exhibits high hazard in the maps for 2% probability of exceedance in 50 years, although its slip rate is poorly constrained.

  9. Centro Princesa, en Madrid (España

    Directory of Open Access Journals (Sweden)

    Lamela, A.

    1968-12-01

    Full Text Available This is a luxury commercial centre, in the very centre of Madrid, and within a high class residential zone. It occupies a whole block, facing four streets, and it includes a luxury hotel, apartments, shopping facilities, offices, car park, and the official headquarters of one of the most important Spanish travelling agencies. The outstanding feature of the «Centro Princesa» is the luxury hotel, which has 250 rooms, suits, social rooms, conventions halls, dance hall, bar, hairdressers saloon, sauna bath, shopping centre, restaurants and secondary services. The luxury flats occupy seven storeys of the central block, 15 apartments per story. Each of these has a sitting room, bedroom, bathroom and kitchen. The carpark, which can hold 300 cars, occupies four underground floor levels. This project is attractive because of its balanced spatial pattern, its clean outline and the quality of the materials, whilst the excellence of its internal appointment also contributes to its overall architectural merit.Este conjunto, situado en una zona residencial de primera categoría, está destinado a: hotel de lujo, apartamentos, locales comerciales, oficinas, aparcamientos de automóviles y a sede de la oficina-despacho central de una de las más importantes agencias de viaje españolas. Ocupa una manzana entera. La unidad predominante del «Centro Princesa» es un hotel de lujo, con 250 habitaciones, «suits», salones sociales, de actos y convenciones, sala de fiestas, bar americano, peluquerías, saunas, galería comercial, restaurantes y dependencias de servicio. Siete plantas del bloque central albergan los apartamentos de lujo, 15 por planta; el apartamento tipo consta de salón, cocina, dormitorio y baño. En cuatro de las plantas de sótano funciona un aparcamiento con capacidad para 300 automóviles. Atrae este conjunto, tanto por el acertado juego de volúmenes, y la limpieza de líneas y materiales —que muestra su composición estética—, como

  10. Transfer knowledge and technology in Madrid; La transferencia de conocimiento y tecnologia en la comunidad de Madrid

    Energy Technology Data Exchange (ETDEWEB)

    Vicente Oliva, M. de; Manera Bassa, J.; Martin del Peso, M.

    2010-07-01

    This paper aims to establish a typology of business behaviour patterns related to Knowledge and Technology Transfer (KTT), as well as an assessment of the situation of the transference process from the Madrid Region companies point of view. Working with data obtained from a survey designed and carried out by the authors to the companies registered in Madrid database and, as a consequence, knowing KTT, we have built groups of enterprises with different behaviours. To obtain the groups we have used cluster techniques over the factors resulting from a correspondence analysis. (Author) 24 refs.

  11. Field investigation of mining-induced seismicity on local geohydrology

    International Nuclear Information System (INIS)

    Hsiung, S.M.; Chowdhury, A.H.; Philip, J.; Blake, W.

    1993-01-01

    Hydraulic response of the rock mass due to earthquakes is one of the concerns in the assessment of the long-term performance of a repository. Studies performed by other researchers indicated no systematic difference between natural earthquakes and mining-induced seismic events. The purpose of this field study at the Lucky Friday Mine is intended to obtain a better understanding regarding the local geohydrologic changes due to mining-induced seismicity and to evaluate analytical methods for simulation of these changes. Three saturated zones with faults and vein features were packed-off along a borehole drilled at approximately 20 degrees downward in a southerly direction from a depth about 1,737 m (5,700 ft) below surface for water pressure monitoring. The response of water pressure change to mine seismicity is found to be more pronounced in Zone 3, which contains the Lucky Friday Main Vein, than Zone 2, with the South Control Fault, and Zone 1, with the associated fractures parallel to the South Control Fault. The maximum observed pressure increase in Zone 3 was about 1.53 x 10 -2 MPa (2.22 psi) due to a seismic event of Richter drops in Zone 1 resulting from a number of seismic events are suspected to be related to slips along the associated fractures of the South Control Fault, or the South Control Fault itself, which initiated the seismic events. Water pressure increase in Zone 3 was found to be a function of event magnitude and distance

  12. Region-specific deterministic and probabilistic seismic hazard ...

    Indian Academy of Sciences (India)

    3National Research Institute of Astronomy and Geophysics (NRIAG), Cairo 11421, Egypt. ∗ ... were assigned to different Mmax values and the selected GMPE to calculate the final hazard ... zone is considered as a prominent seismic gap and.

  13. Identification of seismically susceptible areas in western Himalaya ...

    Indian Academy of Sciences (India)

    This study is an attempt to identify seismically susceptible areas in western Himalaya, using pattern recognition ... a combination of both qualitative and quantita- tive features. .... Three distinct types of zones were identified: S1 was identified as ...

  14. Seismic instrumentation

    International Nuclear Information System (INIS)

    1984-06-01

    RFS or Regles Fondamentales de Surete (Basic Safety Rules) applicable to certain types of nuclear facilities lay down requirements with which compliance, for the type of facilities and within the scope of application covered by the RFS, is considered to be equivalent to compliance with technical French regulatory practice. The object of the RFS is to take advantage of standardization in the field of safety, while allowing for technical progress in that field. They are designed to enable the operating utility and contractors to know the rules pertaining to various subjects which are considered to be acceptable by the Service Central de Surete des Installations Nucleaires, or the SCSIN (Central Department for the Safety of Nuclear Facilities). These RFS should make safety analysis easier and lead to better understanding between experts and individuals concerned with the problems of nuclear safety. The SCSIN reserves the right to modify, when considered necessary, any RFS and specify, if need be, the terms under which a modification is deemed retroactive. The aim of this RFS is to define the type, location and operating conditions for seismic instrumentation needed to determine promptly the seismic response of nuclear power plants features important to safety to permit comparison of such response with that used as the design basis

  15. Deep Geothermal energy potential in Madrid basin; Potencial de la Geotermia profunda en la Cuenca de Madrid

    Energy Technology Data Exchange (ETDEWEB)

    Hidalgo, R.; Sanchez, J.; Ungemach, P.

    2009-07-01

    The Madrid Basin geothermal potential was evidenced in 1980 thanks to an oil exploration well drilled by Shell-Campsa which showed temperatures of 88 degree centigrade and 150 degree centigrade at 1,700 mts and 3,400 mts depth respectively. The low enthalpy geothermal reservoir could be further assessed by four exploratory wells the first one, Pradillo (originals Shell-Campsa oil well), two drilled by ADARO and IGME (Geological survey of Spain) in San Sebastian de los Reyes and Tres Cantos respectively. The latest well, Geomadrid 1, was drilled in 1990 by the Madrid Regional government. The afore mentioned wells have identified a dependable geothermal resource, hosted in a tertiary, clastic, consolidated sandstone reservoir consisting of a thick multilayered sequence (200-800m), with temperatures ranging from 70 degree centigrade to 90 degree centigrade and depths of 1,500 to 2,150 m., overlying a Mesozoic sequence, suitable to be exploited for thermal uses in several district heating grids around Madrid in areas displaying adequate heat loads. A medium temperature reservoir was also identified at the contact between Mesozoic Cretaceous limestones and fractured basement granites at 3,400mts depth, with measured temperatures of 156 degree centigrade, that could be developed and exploited in view of a combined power and heat production (CPH) within the Madrid suburban areas. (Author) 7 refs.

  16. Seismic and Tectonic Regionalization of the State of Michoacan.

    Science.gov (United States)

    Vazquez Rosas, R.; Aguirre, J.; Garduño-Monroy, V. H.; Ramirez-Guzman, L.

    2017-12-01

    In Mexico it is a country with seismically active regions, mainly the zones that are next to the pacific where the zone of subduction is located, in this work we focus on the state of Michoacán, since this has not been completely studied in the last 30 years after the earthquake in Michoacán in 1985. The first most important step is to know the region which are the most seismic zones within the state and one way is to carry out the regionalization of Michoacán identifying the sources of earthquakes as well as where occur more frequently.If we could know each of the factors that influence seismicity and describe every point of the terrain, every rupture, every rock, etc., then we could describe in an analytical way the seismic process and predict the occurrence of earthquakes such as eclipses. Unfortunately the number of parameters is so enormous that we cannot arrive at an exact description; however, we can take advantage of statistical properties to evaluate probabilities, even in the case of small systems such as a particular seismic zone.In this paper, epicenter data were collected from 1970 to 2014, and with them a statistical study was carried out and the epicenter data plotted using data reported by the National Seismological Service and the IRIS catalog as well as some data from the Institute of engineering UNAM. Where earthquakes of equal and greater than M = 4 were used. Graphing these in function with the depth and with that it was graficaron and was made an overlapping the faults of the state and with that it was divided in 4 seismic zones in function of the faults and the localized seismicity.Zone A. is located within the Michoacán Block set of faults, as well as part of the subduction zone on the coast of the state. Seismicity in this area is high. Zone B-1. This is located between the limits of Jalisco and Michoacán in the set of faults called Tepalcatepec depression and limits with the Jorullo-Tacámbaro fracture. At this site seismicity is

  17. Probabilistic seismic hazard assessment. Gentilly 2

    International Nuclear Information System (INIS)

    1996-03-01

    Results of this probabilistic seismic hazard assessment were determined using a suite of conservative assumptions. The intent of this study was to perform a limited hazard assessment that incorporated a range of technically defensible input parameters. To best achieve this goal, input selected for the hazard assessment tended to be conservative with respect to selection of attenuation modes, and seismicity parameters. Seismic hazard estimates at Gentilly 2 were most affected by selection of the attenuation model. Alternative definitions of seismic source zones had a relatively small impact on seismic hazard. A St. Lawrence Rift model including a maximum magnitude of 7.2 m b in the zone containing the site had little effect on the hazard estimate relative to other seismic source zonation models. Mean annual probabilities of exceeding the design peak ground acceleration, and the design response spectrum for the Gentilly 2 site were computed to lie in the range of 0.001 to 0.0001. This hazard result falls well within the range determined to be acceptable for nuclear reactor sites located throughout the eastern United States. (author) 34 refs., 6 tabs., 28 figs

  18. Seismic qualification of equipment

    International Nuclear Information System (INIS)

    Heidebrecht, A.C.; Tso, W.K.

    1983-03-01

    This report describes the results of an investigation into the seismic qualification of equipment located in CANDU nuclear power plants. It is particularly concerned with the evaluation of current seismic qualification requirements, the development of a suitable methodology for the seismic qualification of safety systems, and the evaluation of seismic qualification analysis and testing procedures

  19. Prevalence of heartworm in dogs and cats of Madrid, Spain.

    Science.gov (United States)

    Montoya-Alonso, José Alberto; Morchón, Rodrigo; Falcón-Cordón, Yaiza; Falcón-Cordón, Soraya; Simón, Fernando; Carretón, Elena

    2017-07-26

    Dirofilaria immitis causes heartworm disease, a chronic and potentially fatal cardiopulmonary disease which mainly affects dogs and cats. It is present in most of Spain, due to favourable climatic factors. Madrid, located in the centre of the Iberian Peninsula, is the most highly populated city in the country. There is a lack of current data on canine heartworm and there are no published epidemiological data regarding feline heartworm in this region, therefore the aim of this study was to assess the prevalence and current distribution of canine and feline dirofilariosis in the province of Madrid. Serum samples from 1716 dogs and 531 cats, from animals living in the metropolitan area of Madrid and adjacent areas, were studied. All the samples, either from cats and dogs, were tested for circulating D. immitis antigens using a commercial immunochromatographic test kit. Furthermore, to establish the seroprevalence of heartworm infection in cats, serological techniques for anti-D. immitis and anti-Wolbachia antibody detection were used. Prevalence of D. immitis in the canine population of Madrid was 3%, showing an increase in comparison to previous data. The presence of heartworm in the city centre could be influenced by the presence of Urban Heat Islands, while the positive dogs from metropolitan and adjacent areas were mainly located under the influence of rivers. Regarding cats, 0.2% were positive to the antigens test and 7.3% were seropositive to both anti-D. immitis and Wolbachia surface protein antibodies, which demonstrate the presence of feline heartworm in Madrid. Seropositive cats were present in the same areas where positive dogs were found. Indoor/outdoor cats showed the highest seroprevalence whereas the lowest corresponded to indoor cats, demonstrating that prophylactic treatments should be carried out regardless of lifestyle. Infection was found in 2.2% of dogs and 6.7% of the cats < 1 year-old, which indicates that early preventive campaigns in puppies

  20. Southern Appalachian Regional Seismic Network

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, S.C.C.; Johnston, A.C.; Chiu, J.M. [Memphis State Univ., TN (United States). Center for Earthquake Research and Information

    1994-08-01

    The seismic activity in the southern Appalachian area was monitored by the Southern Appalachian Regional Seismic Network (SARSN) since late 1979 by the Center for Earthquake Research and Information (CERI) at Memphis State University. This network provides good spatial coverage for earthquake locations especially in east Tennessee. The level of activity concentrates more heavily in the Valley and Ridge province of eastern Tennessee, as opposed to the Blue Ridge or Inner Piedmont. The large majority of these events lie between New York - Alabama lineament and the Clingman/Ocoee lineament, magnetic anomalies produced by deep-seated basement structures. Therefore SARSN, even with its wide station spacing, has been able to define the essential first-order seismological characteristics of the Southern Appalachian seismic zone. The focal depths of the southeastern U.S. earthquakes concentrate between 8 and 16 km, occurring principally beneath the Appalachian overthrust. In cross-sectional views, the average seismicity is shallower to the east beneath the Blue Ridge and Piedmont provinces and deeper to the west beneath the Valley and Ridge and the North American craton. Results of recent focal mechanism studies by using the CERI digital earthquake catalog between October, 1986 and December, 1991, indicate that the basement of the Valley and Ridge province is under a horizontal, NE-SW compressive stress. Right-lateral strike-slip faulting on nearly north-south fault planes is preferred because it agrees with the trend of the regional magnetic anomaly pattern.

  1. Southern Appalachian Regional Seismic Network

    International Nuclear Information System (INIS)

    Chiu, S.C.C.; Johnston, A.C.; Chiu, J.M.

    1994-08-01

    The seismic activity in the southern Appalachian area was monitored by the Southern Appalachian Regional Seismic Network (SARSN) since late 1979 by the Center for Earthquake Research and Information (CERI) at Memphis State University. This network provides good spatial coverage for earthquake locations especially in east Tennessee. The level of activity concentrates more heavily in the Valley and Ridge province of eastern Tennessee, as opposed to the Blue Ridge or Inner Piedmont. The large majority of these events lie between New York - Alabama lineament and the Clingman/Ocoee lineament, magnetic anomalies produced by deep-seated basement structures. Therefore SARSN, even with its wide station spacing, has been able to define the essential first-order seismological characteristics of the Southern Appalachian seismic zone. The focal depths of the southeastern U.S. earthquakes concentrate between 8 and 16 km, occurring principally beneath the Appalachian overthrust. In cross-sectional views, the average seismicity is shallower to the east beneath the Blue Ridge and Piedmont provinces and deeper to the west beneath the Valley and Ridge and the North American craton. Results of recent focal mechanism studies by using the CERI digital earthquake catalog between October, 1986 and December, 1991, indicate that the basement of the Valley and Ridge province is under a horizontal, NE-SW compressive stress. Right-lateral strike-slip faulting on nearly north-south fault planes is preferred because it agrees with the trend of the regional magnetic anomaly pattern

  2. German seismic regulations

    International Nuclear Information System (INIS)

    Danisch, Ruediger

    2002-01-01

    Rules and regulations for seismic design in Germany cover the following: seismic design of conventional buildings; and seismic design of nuclear facilities. Safety criteria for NPPs, accident guidelines, and guidelines for PWRs as well as safety standards are cited. Safety standards concerned with NPPs seismic design include basic principles, soil analysis, design of building structures, design of mechanical and electrical components, seismic instrumentation, and measures to be undertaken after the earthquake

  3. Estimation of pore pressure from seismic velocities

    International Nuclear Information System (INIS)

    Perez, Zayra; Ojeda, German Y; Mateus, Darwin

    2009-01-01

    On pore pressure calculations it is common to obtain a profile in a well bore, which is then extrapolated toward offset wells. This practice might generate mistakes on pore pressure measurements, since geological conditions may change from a well bore to another, even into the same basin. Therefore, it is important to use other tools which allow engineers not only to detect and estimate in an indirect way overpressure zones, but also to keep a lateral tracking of possible changes that may affect those values in the different formations. Taking into account this situation, we applied a methodology that estimates formation pressure from 3D seismic velocities by using the Eaton method. First, we estimated formation pore pressure; then, we identified possible overpressure zones. Finally, those results obtained from seismic information were analyzed involving well logs and pore pressure tests, in order to compare real data with prediction based on seismic information from the Colombian foothill.

  4. Seismic reevaluation of existing nuclear power plants

    International Nuclear Information System (INIS)

    Hennart, J.C.

    1978-01-01

    The codes and regulations governing Nuclear Power Plant seismic analysis are continuously becoming more stringent. In addition, design ground accelerations of existing plants must sometimes be increased as a result of discovery of faulting zones or recording of recent earthquakes near the plant location after plant design. These new factors can result in augmented seismic design criteria. Seismic reanalysius of the existing Nuclear Power Plant structures and equipments is necessary to prevent the consequences of newly postulated accidents that could cause undue risk to the health or safety of the public. This paper reviews the developments of seismic analysis as applied to Nuclear Power Plants and the methods used by Westinghouse to requalify existing plants to the most recent safety requirements. (author)

  5. 2 obras de Fisac en Madrid: Edificio «Vega» para oficinas y vivienda unifamiliar en Somosaguas

    Directory of Open Access Journals (Sweden)

    Fisac, M.

    1967-11-01

    Full Text Available 2 Buildings by M. Fisac «Vega» office building in Madrid This aesthetically thought out building is eminently urban, with natural gardens and no enclosing fences or artificial obstacles separating the site from the street. The «Vega» building comprises a central block, with the vertical communications, including stairs and three lifts, and and three wings that correspond to the triangular shape of the site. The basic constructional mediiun, which has been very wisely used, both for the paraments and flooring, is untreated reinforced concrete. Single family dwelling at Somosaguas, Madrid The various zones of the building have been planned mainly in relation to their orientation, so that the living zone faces to the South, and the bedrooms are on the East. Also, the separate parts of the building are situated at various levels, to have as much sunshine as possible, and achieve optimum adaptation to the site profile. The garden is also planned on multiple levels in accord with the ground topography. In this building, too, untreated concrete has been adopted almost exclusively, together with precast units and granite stone.Edificio «Vega» para oficinas, en Madrid Estéticamente concebido con un carácter eminentemente urbano, con ajardinamientos libres, sin vallas ni obstáculos a las calles colindantes, dicho edificio «Vega» está compuesto: — por un nudo central, en el que están situados los enlaces verticales: una escalera y tres ascensores; — y tres ramas que corresponden a los tres vértices del triángulo del solar. El material fundamental y sabiamente empleado en estructura y forjados, es el hormigón armado visto. Vivienda unifamiliar en Somosaguas, Madrid La composición de las distintas ZONAS del edificio se ha hecho atendiendo, principalmente, a las características de vistas y orientación, quedando, a mediodía, la zona de estar, y a saliente, la de dormitorios. Asimismo, las diversas partes del edificio aparecen

  6. Deterministic seismic hazard macrozonation of India

    Indian Academy of Sciences (India)

    The sesismotectonic map of the study area was prepared by considering the faults, lineaments and the shear zones which are associated with earthquakes of magnitude 4 and above. A new program was developed in MATLAB for smoothing of the point sources. For assessing the seismic hazard, the study area was divided ...

  7. RESERVOIR CHARACTERIZATION USING SEISMIC AND WELL ...

    African Journals Online (AJOL)

    Osondu

    2012-06-19

    Jun 19, 2012 ... analysis of the entire pay zone is impractical. A typical seismic section of Niger Delta will reveal number of synsedimentary structures resulting from the deltaic tectonic. The structures include growth faults; which are normal faults characterization by a concave fault plane resulting from the decrease of dip at ...

  8. Edificio Foster Wheeler. Madrid/España

    Directory of Open Access Journals (Sweden)

    Arangüena, José María

    1988-04-01

    Full Text Available This article describes in detail the characteristics of a building in Madrid whose structure, in reinforced concrete, is set into the foundation with individual footings. Services are found in a nucleus made up of a concrete element, designed to stabilize the whole of the structure with respect to horizontal forces. All parts of the building have been designed and constructed in accordance with existing regulations.

    Este artículo describe, con detalle, las características de un edificio construido en Madrid, cuya estructura se tía realizado en hormigón armado y cimentada sobre el suelo mediante zapatas individuales. El núcleo donde se encuentran los servicios es un elemento de hormigón, cuya misión estructural consiste en estabilizar el conjunto de la estructura frente a los esfuerzos horizontales. Todos los elementos del edificio han sido realizados de acuerdo con la Normativa Vigente.

  9. Structure of the Kasbah fold zone (Agadir bay, Morocco. Implications on the chronology of the recent tectonics of the western High Atlas and on the seismic hazard of the Agadir area

    Directory of Open Access Journals (Sweden)

    Samaka, F.

    2009-12-01

    Full Text Available Detailed re-interpretation of the north-eastern segment of a profile realized across the Agadir bay along a NE-SW trend and crosscutting the main structures, together with analysis of available isochron maps, allowed us to retrace the geological history of the offshore western High Atlas. Two tectonostratigraphic sequences were distinguished: Unit II, which displays a simple structure, laying unconformably on Unit I, with a more complex structure dominated by a reverse fault (F1 striking E-W with a dip to the north. Correlation to boreholes Souss-1 and AGM-1 allowed us to assign Unit I to the Triassic – Palaeogene and Unit II to the Miocene – Present. The NE fault block shows a ramp-flat fault plane (F2 with an overlying SW-vergent fold that can be interpreted as a fault-bend fold. Three main stages were distinguished: (1 during the Cretaceous, F1 could have been a syndepositional normal fault with the NE block moving downwards; (2 towards the beginning of the Tertiary, the displacement of plane F2 induced the development of a fault-bend fold and erosion of the forelimb and hinge of the fold; displacement along F2 was transferred to fault F1; (3 afterwards, during the Miocene, reverse motion of F1 deformed and tilted the plane F2 and accentuated the folded structure. This evolution is typical for a frontal basin above a fault-related fold. Evaluation of the thickness and bed depth differences shows that the largest growth rate was recorded in Late Miocene times. Seismic activity recorded in the Agadir bay appears to be clearly related to this fault zone, as inferred from focal mechanisms. Seismic moment evaluation suggests that earthquakes of magnitude Mw≥6 are likely to occur, but could not be much larger because of the fault segmentation geometry of the High Atlas Front.

    A partir de una detallada reinterpretación del segmento nororiental de un perfil que corta las principales estructuras de la bahía de Agadir a lo largo de una

  10. Proterozoic structure, cambrian rifting, and younger faulting as revealed by a regional seismic reflection network in the Southern Illinois Basin

    Science.gov (United States)

    Potter, C.J.; Drahovzal, James A.; Sargent, M.L.; McBride, J.H.

    1997-01-01

    Four high-quality seismic reflection profiles through the southern Illinois Basin, totaling 245 km in length, provide an excellent regional subsurface stratigraphic and structural framework for evaluation of seismic risk, hydrocarbon occurrence, and other regional geologic studies. These data provide extensive subsurface information on the geometry of the intersection of the Cambrian Reelfoot and Rough Creek rifts, on extensive Proterozoic reflection sequences, and on structures (including the Fluorspar Area Fault Complex and Hicks Dome) that underlie a transitional area between the well-defined New Madrid seismic zone (to the southwest) and a more diffuse area of seismicity in the southern Illinois Basin. Our principal interpretations from these data are listed here in order of geologic age, from oldest to youngest: 1. Prominent Proterozoic layering, possibly equivalent to Proterozoic (???1 Ga) Middle Run Formation clastic strata and underlying (1.3-1.5 Ga) volcanic rocks of the East Continent rift basin, has been strongly deformed, probably as part of the Grenville foreland fold and thrust belt. 2. A well-defined angular unconformity is seen in many places between Proterozoic and Cambrian strata; a post-Grenville Proterozoic sequence is also apparent locally, directly beneath the base of the Cambrian. 3. We infer a major reversal in Cambrian rift polarity (accommodation zone) in the Rough Creek Graben in western Kentucky. 4. Seismic facies analysis suggests the presence of basin-floor fan complexes at and near the base of the Cambrian interval and within parts of a Proterozoic post-Grenville sequence in several parts of the Rough Creek Graben. 5. There is an abrupt pinchout of the Mount Simon Sandstone against crystalline basement beneath the Dale Dome (near the Texaco no. 1 Cuppy well, Hamilton County) in southeastern Illinois, and a more gradual Mount Simon pinchout to the southeast. 6. Where crossed by the seismic reflection line in southeast Illinois, some

  11. Actitudes autoritarias y violencia en Madrid Authoritarian attitudes and violence in Madrid

    Directory of Open Access Journals (Sweden)

    Florentino Moreno Martín

    1999-04-01

    Full Text Available Uno de los objetivos del Estudio Multicéntrico sobre Actitudes y Normas Culturales frente a la Violencia (proyecto ACTIVA es analizar la relación entre las actitudes favorecedoras de la violencia y las conductas violentas. En el presente artículo se estudia la relación entre actitudes autoritarias y dos componentes de la violencia: su justificación y su realización efectiva. La recolección de datos se hizo en la ciudad de Madrid entre octubre y diciembre de 1996. Se trabajó con una muestra representativa de 1 219 personas entrevistadas en sus domicilios a partir del cuestionario común del proyecto ACTIVA, al cual se añadieron algunas preguntas. Globalmente considerada, la muestra tuvo una puntuación baja en la escala de autoritarismo. El grupo de personas que más justificaron la violencia tuvo puntuaciones más altas en autoritarismo, al igual que las personas en cuyas conductas habituales se observó un nivel de agresión mayor. Las actitudes más autoritarias se constataron en barrios de bajos recursos económicos, en personas no activas laboralmente, en las de nivel educativo más bajo y en las que se identificaron con una ideología de derecha. Si los más autoritarios justifican y ejercen más la violencia, es preciso fomentar actitudes de crítica hacia quienes abusan del poder y respeto por las diferencias, a fin de prevenir la aparición de estas conductas, sin olvidar la influencia de las variables sociales mencionadas anteriormente.One of the objectives of the Multicentric Study on Cultural Norms and Attitudes Toward Violence (Estudio Multicéntrico sobre Actitudes y Normas Culturales frente a la Violencia, the ACTIVA project is to analyze the relationship between those attitudes that foster violence and the violent behaviors themselves. This article examines the relationship between attitudes and two components of violence: its justification and its actual occurrence. Data were collected in Madrid between October and

  12. Seismic characteristics of the area around the Philippine Research Reactor (PRR-1)

    International Nuclear Information System (INIS)

    Paz, L.R. de la; Palattao, M.V.B.; Estacio, J.F.; Ragiles, S.O.

    1989-01-01

    The seismic characteristics of the PRR-1 site are discussed. A study was made about seismicity, acceleration values and the recent seismic history of the site. The incidence of seismic events in Manila and Quezon City and their intensities were also recorded and plotted. The liquefaction potential was calculated. No zone of liquefaction was found existing in the site area. (Auth.). 6 tabs., 18 refs., 7 figs

  13. Original earthquake design basis in light of recent seismic hazard studies

    International Nuclear Information System (INIS)

    Petrovski, D.

    1993-01-01

    For the purpose of conceiving the framework within which efforts have been made in the eastern countries to construct earthquake resistant nuclear power plants, a review of the development and application of the seismic zoning map of USSR is given. The normative values of seismic intensity and acceleration are discussed from the aspect of recent probabilistic seismic hazard studies. To that effect, presented briefly in this paper is the methodology of probabilistic seismic hazard analysis. (author)

  14. Computerized tomography in Community of Madrid. Reference dosimetric measurements

    International Nuclear Information System (INIS)

    Ruiz Sanz, S.; Calzado, A.; Melchor, M.; Marco, M.

    1994-01-01

    A total of about 43 computed tomography scanners were operating in the Autonomous Community of Madrid during 1991. A sample of 14 facilities was selected to perform dosimetric measurements in order to obtain characteristic dose profiles. From these, some quantities as the computed tomography dose index and the enhancement factor were calculated and analysed for the most common technique settings. Relations were established between the dosimetric results and technical characteristics of the scanners. (Author)

  15. Estimating Fault Friction From Seismic Signals in the Laboratory

    Science.gov (United States)

    Rouet-Leduc, Bertrand; Hulbert, Claudia; Bolton, David C.; Ren, Christopher X.; Riviere, Jacques; Marone, Chris; Guyer, Robert A.; Johnson, Paul A.

    2018-02-01

    Nearly all aspects of earthquake rupture are controlled by the friction along the fault that progressively increases with tectonic forcing but in general cannot be directly measured. We show that fault friction can be determined at any time, from the continuous seismic signal. In a classic laboratory experiment of repeating earthquakes, we find that the seismic signal follows a specific pattern with respect to fault friction, allowing us to determine the fault's position within its failure cycle. Using machine learning, we show that instantaneous statistical characteristics of the seismic signal are a fingerprint of the fault zone shear stress and frictional state. Further analysis of this fingerprint leads to a simple equation of state quantitatively relating the seismic signal power and the friction on the fault. These results show that fault zone frictional characteristics and the state of stress in the surroundings of the fault can be inferred from seismic waves, at least in the laboratory.

  16. The Madrid School of Neurology (1885-1939).

    Science.gov (United States)

    Giménez-Roldán, S

    2015-01-01

    The emergence of neurology in Madrid between 1885 and 1939 had well-defined characteristics. On foundations laid by Cajal and Río-Hortega, pioneers combined clinical practice with cutting-edge neurohistology and neuropathology research. Luis Simarro, trained in Paris, taught many talented students including Gayarre, Achúcarro and Lafora. The untimely death of Nicolás Achúcarro curtailed his promising career, but he still completed the clinicopathological study of the first American case of Alzheimer's disease. On returning to Spain, he studied glial cells, including rod cells. Rodríguez Lafora described progressive myoclonus epilepsy and completed experimental studies of corpus callosum lesions and clinical and neuropathology studies of senile dementia. He fled to Mexico at the end of the Spanish Civil War (1936-1939). Sanchís Banús, a sterling clinical neurologist, described the first cluster of Huntington's disease in Spain, and he and Río-Hortega joined efforts to determine that pallidal degeneration underlies rigidity in advanced stages of the disease. Just after the war, Alberca Llorente eruditely described inflammatory diseases of the neuraxis. Manuel Peraita studied "the neurology of hunger" with data collected during the siege of Madrid. Dionisio Nieto, like many exiled intellectuals, settled in Mexico DF, where he taught neurohistological methods and neuropsychiatry in the tradition of the Madrid School of Neurology. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  17. Los atentados de Madrid en la prensa francesa

    Directory of Open Access Journals (Sweden)

    Emilia Martos Contreras

    2009-12-01

    Full Text Available El presente artículo recoge algunas de las conclusiones obtenidas en la investigación de los atentados de Madrid del 11 de marzo de 2003, a través de la prensa francesa . El análisis se centra en los intensos días posteriores al 11-M, hasta el fin de la jornada electoral el 14 de marzo. Se han utilizado un total de catorce cabeceras, entre periódicos y revistas francesas de distintas tendencias y cuotas de difusión. Con ellas se ha analizado la reacción de la opinión pública gala ante la masacre de Madrid y cómo analizaron los acontecimientos que se sucedieron entre ese día y el 14-M.______________________ABSTRACT:The present article gathers some conclusion obtained in the research about the terrorist attacks in Madrid on 11th March, 2003, through the French press. The analysis centres on the intense days between the terrorist attack and the polling day on 14th March. Fourteen head-boards have been used, among French newspapers and magazines, with different tendency and different diffusion rates.  

  18. Seismic Design of a Single Bored Tunnel: Longitudinal Deformations and Seismic Joints

    Science.gov (United States)

    Oh, J.; Moon, T.

    2018-03-01

    The large diameter bored tunnel passing through rock and alluvial deposits subjected to seismic loading is analyzed for estimating longitudinal deformations and member forces on the segmental tunnel liners. The project site has challenges including high hydrostatic pressure, variable ground profile and high seismic loading. To ensure the safety of segmental tunnel liner from the seismic demands, the performance-based two-level design earthquake approach, Functional Evaluation Earthquake and Safety Evaluation Earthquake, has been adopted. The longitudinal tunnel and ground response seismic analyses are performed using a three-dimensional quasi-static linear elastic and nonlinear elastic discrete beam-spring elements to represent segmental liner and ground spring, respectively. Three components (longitudinal, transverse and vertical) of free-field ground displacement-time histories evaluated from site response analyses considering wave passage effects have been applied at the end support of the strain-compatible ground springs. The result of the longitudinal seismic analyses suggests that seismic joint for the mitigation measure requiring the design deflection capacity of 5-7.5 cm is to be furnished at the transition zone between hard and soft ground condition where the maximum member forces on the segmental liner (i.e., axial, shear forces and bending moments) are induced. The paper illustrates how detailed numerical analyses can be practically applied to evaluate the axial and curvature deformations along the tunnel alignment under difficult ground conditions and to provide the seismic joints at proper locations to effectively reduce the seismic demands below the allowable levels.

  19. Seismic rupture modelling, strong motion prediction and seismic hazard assessment: fundamental and applied approaches

    International Nuclear Information System (INIS)

    Berge-Thierry, C.

    2007-05-01

    The defence to obtain the 'Habilitation a Diriger des Recherches' is a synthesis of the research work performed since the end of my Ph D. thesis in 1997. This synthesis covers the two years as post doctoral researcher at the Bureau d'Evaluation des Risques Sismiques at the Institut de Protection (BERSSIN), and the seven consecutive years as seismologist and head of the BERSSIN team. This work and the research project are presented in the framework of the seismic risk topic, and particularly with respect to the seismic hazard assessment. Seismic risk combines seismic hazard and vulnerability. Vulnerability combines the strength of building structures and the human and economical consequences in case of structural failure. Seismic hazard is usually defined in terms of plausible seismic motion (soil acceleration or velocity) in a site for a given time period. Either for the regulatory context or the structural specificity (conventional structure or high risk construction), seismic hazard assessment needs: to identify and locate the seismic sources (zones or faults), to characterize their activity, to evaluate the seismic motion to which the structure has to resist (including the site effects). I specialized in the field of numerical strong-motion prediction using high frequency seismic sources modelling and forming part of the IRSN allowed me to rapidly working on the different tasks of seismic hazard assessment. Thanks to the expertise practice and the participation to the regulation evolution (nuclear power plants, conventional and chemical structures), I have been able to work on empirical strong-motion prediction, including site effects. Specific questions related to the interface between seismologists and structural engineers are also presented, especially the quantification of uncertainties. This is part of the research work initiated to improve the selection of the input ground motion in designing or verifying the stability of structures. (author)

  20. Antonio Quilis, La concodancia gramatiaal en Za Zengua espanola hablada en Madrid, C. S. I. C., Madrid 1983, pags. 128

    Directory of Open Access Journals (Sweden)

    Mitja Skubic

    1983-01-01

    Full Text Available El libra de Antonio Quilis, de poco más de cien páginas, nos ofrece los resultados de las encuestas sabre la concordancia sintáctica en el habla de Madrid. El Autor que es también cultivador y conocedor de la fonética del español­ pensemos en su importante trabajo sobre la fonética acústica de la lengua española (Gredos, Madrid 1981 - vuelve aqué a su vocacion de sintáctico, visible en sus trabajos sabre la estructura del español la edición de la Gramática de Nebri­ja y en el amor con que cuidó la presentación al mundo de habla castellana de las obras de B. Pottier.

  1. Seismic Structure of Perth Basin (Australia) and surroundings from Passive Seismic Deployments

    Science.gov (United States)

    Issa, N.; Saygin, E.; Lumley, D. E.; Hoskin, T. E.

    2016-12-01

    We image the subsurface structure of Perth Basin, Western Australia and surroundings by using ambient seismic noise data from 14 seismic stations recently deployed by University of Western Australia (UWA) and other available permanent stations from Geoscience Australia seismic network and the Australian Seismometers in Schools program. Each of these 14 UWA seismic stations comprises a broadband sensor and a high fidelity 3-component 10 Hz geophone, recording in tandem at 250 Hz and 1000 Hz. The other stations used in this study are equipped with short period and broadband sensors. In addition, one shallow borehole station is operated with eight 3 component geophones at depths of between 2 and 44 m. The network is deployed to characterize natural seismicity in the basin and to try and identify any microseismic activity across Darling Fault Zone (DFZ), bounding the basin to the east. The DFZ stretches to approximately 1000 km north-south in Western Australia, and is one of the longest fault zones on the earth with a limited number of detected earthquakes. We use seismic noise cross- and auto-correlation methods to map seismic velocity perturbations across the basin and the transition from DFZ to the basin. Retrieved Green's functions are stable and show clear dispersed waveforms. Travel times of the surface wave Green's functions from noise cross-correlations are inverted with a two-step probabilistic framework to map the absolute shear wave velocities as a function of depth. The single station auto-correlations from the seismic noise yields P wave reflectivity under each station, marking the major discontinuities. Resulting images show the shear velocity perturbations across the region. We also quantify the variation of ambient seismic noise at different depths in the near surface using the geophones in the shallow borehole array.

  2. Seismic hazard map of the western hemisphere

    Science.gov (United States)

    Shedlock, K.M.; Tanner, J.G.

    1999-01-01

    horizontal force a building should be able to withstand during an earthquake. This seismic hazard map of the Americas depicts the likely level of short-period ground motion from earthquakes in a fifty-year window. Short-period ground motions effect short-period structures (e.g., one-to-two story buildings). The largest seismic hazard values in the western hemisphere generally occur in areas that have been, or are likely to be, the sites of the largest plate boundary earthquakes. Although the largest earthquakes ever recorded are the 1960 Chile and 1964 Alaska subduction zone earthquakes, the largest seismic hazard (PGA) value in the Americas is in Southern California (U.S.), along the San Andreas fault.

  3. Seismic hazard map of the western hemisphere

    Directory of Open Access Journals (Sweden)

    J. G. Tanner

    1999-06-01

    specify the horizontal force a building should be able to withstand during an earthquake. This seismic hazard map of the Americas depicts the likely level of short-period ground motion from earthquakes in a fifty-year window. Short-period ground motions effect short-period structures (e.g., one-to-two story buildings. The largest seismic hazard values in the western hemisphere generally occur in areas that have been, or are likely to be, the sites of the largest plate boundary earthquakes. Although the largest earthquakes ever recorded are the 1960 Chile and 1964 Alaska subduction zone earthquakes, the largest seismic hazard (PGA value in the Americas is in Southern California (U.S., along the San Andreas fault.

  4. Input for seismic hazard assessment using Vrancea seismic source region

    International Nuclear Information System (INIS)

    Ivan, Iren-Adelina; Enescu, B.D.; Pantea, A.

    1998-01-01

    We use an extended and combined data base including historical and modern, qualitative and quantitative data, i.e., more than 25 events during the period 1790 - 1990 with epicentral/maximum intensities ranging from X to V degree (MSK scale), the variation interval of isoseismal curves ranging from IX th to III rd degree. The data set was analysed using both the sum phasor techniques of Ridelek and Sacks (1984) for different magnitudes and depth intervals and the Stepp's method. For the assessment of seismic hazard we need a pattern of seismic source regions including an estimation for the maximum expected magnitude and the return period for the studied regions. Another necessary step in seismic hazard assessment is to develop attenuation relationships specific to a seismogenic zone, particularly to sub-crustal earthquakes of Vrancea region. The conceptual frame involves the use of appropriate decay models and consideration of the randomness in the attenuation, taking into account the azimuthal variation of the isoseist shapes. (authors)

  5. Seismic intrusion detector system

    Science.gov (United States)

    Hawk, Hervey L.; Hawley, James G.; Portlock, John M.; Scheibner, James E.

    1976-01-01

    A system for monitoring man-associated seismic movements within a control area including a geophone for generating an electrical signal in response to seismic movement, a bandpass amplifier and threshold detector for eliminating unwanted signals, pulse counting system for counting and storing the number of seismic movements within the area, and a monitoring system operable on command having a variable frequency oscillator generating an audio frequency signal proportional to the number of said seismic movements.

  6. National Seismic Station

    International Nuclear Information System (INIS)

    Stokes, P.A.

    1982-06-01

    The National Seismic Station was developed to meet the needs of regional or worldwide seismic monitoring of underground nuclear explosions to verify compliance with a nuclear test ban treaty. The Station acquires broadband seismic data and transmits it via satellite to a data center. It is capable of unattended operation for periods of at least a year, and will detect any tampering that could result in the transmission of unauthentic seismic data

  7. The seismic monitoring network of Mt. Vesuvius

    Directory of Open Access Journals (Sweden)

    Massimo Orazi

    2013-11-01

    Full Text Available Mt. Vesuvius (southern Italy is one of the most hazardous volcanoes in the world. Its activity is currently characterized by moderate seismicity, with hypocenters located beneath the crater zone with depth rarely exceeding 5 km and magnitudes generally less than 3. The current configuration of the seismic monitoring network of Mt. Vesuvius consists of 18 seismic stations and 7 infrasound microphones. During the period 2006-2010 a seismic array with 48 channels was also operative. The station distribution provides appropriate coverage of the area around the volcanic edifice. The current development of the network and its geometry, under conditions of low seismic noise, allows locating seismic events with M<1. Remote instruments continuously transmit data to the main acquisition center in Naples. Data transmission is realized using different technological solutions based on UHF, Wi-Fi radio links, and TCP/IP client-server applications. Data are collected in the monitoring center of the Osservatorio Vesuviano (Italian National Institute of Geophysics and Volcanology, Naples section, which is equipped with systems for displaying and analyzing signals, using both real-time automatic and manual procedures. 24-hour surveillance allows to immediately communicate any significant anomaly to the Civil Protection authorities.

  8. Quantitative Seismic Amplitude Analysis

    NARCIS (Netherlands)

    Dey, A.K.

    2011-01-01

    The Seismic Value Chain quantifies the cyclic interaction between seismic acquisition, imaging and reservoir characterization. Modern seismic innovation to address the global imbalance in hydrocarbon supply and demand requires such cyclic interaction of both feed-forward and feed-back processes.

  9. Man-caused seismicity of Kuzbass

    Science.gov (United States)

    Emanov, Alexandr; Emanov, Alexey; Leskova, Ekaterina; Fateyev, Alexandr

    2010-05-01

    A natural seismicity of Kuznetsk Basin is confined in the main to mountain frame of Kuznetsk hollow. In this paper materials of experimental work with local station networks within sediment basin are presented. Two types of seismicity display within Kuznetsk hollow have been understood: first, man-caused seismic processes, confined to mine working and concentrated on depths up to one and a half of km; secondly, seismic activations on depths of 2-56 km, not coordinated in plan with coal mines. Every of studied seismic activations consists of large quantity of earthquakes of small powers (Ms=1-3). From one to first tens of earthquakes were recorded in a day. The earthquakes near mine working shift in space along with mine working, and seismic process become stronger at the instant a coal-plough machine is operated, and slacken at the instant the preventive works are executed. The seismic processes near three lavas in Kuznetsk Basin have been studied in detail. Uplift is the most typical focal mechanism. Activated zone near mine working reach in diameter 1-1,5 km. Seismic activations not linked with mine working testify that the subsoil of Kuznetsk hollow remain in stress state in whole. The most probable causes of man-caused action on hollow are processes, coupled with change of physical state of rocks at loss of methane from large volume or change by mine working of rock watering in large volume. In this case condensed rocks, lost gas and water, can press out upwards, realizing the reverse fault mechanism of earthquakes. A combination of stress state of hollow with man-caused action at deep mining may account for incipient activations in Kuznetsk Basin. Today earthquakes happen mainly under mine workings, though damages of workings themselves do not happen, but intensive shaking on surface calls for intent study of so dangerous phenomena. In 2009 replicates of the experiment on research of seismic activations in area of before investigated lavas have been conducted

  10. Seismic migration in generalized coordinates

    Science.gov (United States)

    Arias, C.; Duque, L. F.

    2017-06-01

    Reverse time migration (RTM) is a technique widely used nowadays to obtain images of the earth’s sub-surface, using artificially produced seismic waves. This technique has been developed for zones with flat surface and when applied to zones with rugged topography some corrections must be introduced in order to adapt it. This can produce defects in the final image called artifacts. We introduce a simple mathematical map that transforms a scenario with rugged topography into a flat one. The three steps of the RTM can be applied in a way similar to the conventional ones just by changing the Laplacian in the acoustic wave equation for a generalized one. We present a test of this technique using the Canadian foothills SEG velocity model.

  11. Seismic migration in generalized coordinates

    International Nuclear Information System (INIS)

    Arias, C.; Duque, L. F.

    2017-01-01

    Reverse time migration (RTM) is a technique widely used nowadays to obtain images of the earth’s sub-surface, using artificially produced seismic waves. This technique has been developed for zones with flat surface and when applied to zones with rugged topography some corrections must be introduced in order to adapt it. This can produce defects in the final image called artifacts. We introduce a simple mathematical map that transforms a scenario with rugged topography into a flat one. The three steps of the RTM can be applied in a way similar to the conventional ones just by changing the Laplacian in the acoustic wave equation for a generalized one. We present a test of this technique using the Canadian foothills SEG velocity model. (paper)

  12. Microzonation of Seismic Hazard Potential in Taipei, Taiwan

    Science.gov (United States)

    Liu, K. S.; Lin, Y. P.

    2017-12-01

    The island of Taiwan lies at the boundary between the Philippine Sea plate and the Eurasia plate. Accordingly, the majority of seismic energy release near Taiwan originates from the two subduction zones. It is therefore not surprising that Taiwan has repeatedly been struck by large earthquakes such as 1986 Hualien earthquake, 1999 Chi Chi and 2002 Hualien earthquake. Microzonation of seismic hazard potential becomes necessary in Taipei City for the Central Geological Survey announced the Sanchiao active fault as Category II. In this study, a catalog of more than 2000 shallow earthquakes occurred from 1900 to 2015 with Mw magnitudes ranging from 5.0 to 8.2, and 11 disastrous earthquakes occurred from 1683-1899, as well as Sanchiao active fault in the vicinity are used to estimate the seismic hazard potential in Taipei City for seismic microzonation. Furthermore, the probabilities of seismic intensity exceeding CWB intensity 5, 6, 7 and MMI VI, VII, VIII in 10, 30, and 50-year periods in the above areas are also analyzed for the seismic microzonation. Finally, by comparing with the seismic zoning map of Taiwan in current building code that was revised after 921 earthquakes, Results of this study will show which areas with higher earthquake hazard potential in Taipei City. They provide a valuable database for the seismic design of critical facilities. It will help mitigate Taipei City earthquake disaster loss in the future, as well as provide critical information for emergency response plans.

  13. Assessing the seismic risk potential of South America

    Science.gov (United States)

    Jaiswal, Kishor; Petersen, Mark D.; Harmsen, Stephen; Smoczyk, Gregory M.

    2016-01-01

    We present here a simplified approach to quantifying regional seismic risk. The seismic risk for a given region can be inferred in terms of average annual loss (AAL) that represents long-term value of earthquake losses in any one year caused from a long-term seismic hazard. The AAL are commonly measured in the form of earthquake shaking-induced deaths, direct economic impacts or indirect losses caused due to loss of functionality. In the context of South American subcontinent, the analysis makes use of readily available public data on seismicity, population exposure, and the hazard and vulnerability models for the region. The seismic hazard model was derived using available seismic catalogs, fault databases, and the hazard methodologies that are analogous to the U.S. Geological Survey’s national seismic hazard mapping process. The Prompt Assessment of Global Earthquakes for Response (PAGER) system’s direct empirical vulnerability functions in terms of fatality and economic impact were used for performing exposure and risk analyses. The broad findings presented and the risk maps produced herein are preliminary, yet they do offer important insights into the underlying zones of high and low seismic risks in the South American subcontinent. A more detailed analysis of risk may be warranted by engaging local experts, especially in some of the high risk zones identified through the present investigation.

  14. Source modelling in seismic risk analysis for nuclear power plants

    International Nuclear Information System (INIS)

    Yucemen, M.S.

    1978-12-01

    The proposed probabilistic procedure provides a consistent method for the modelling, analysis and updating of uncertainties that are involved in the seismic risk analysis for nuclear power plants. The potential earthquake activity zones are idealized as point, line or area sources. For these seismic source types, expressions to evaluate their contribution to seismic risk are derived, considering all the possible site-source configurations. The seismic risk at a site is found to depend not only on the inherent randomness of the earthquake occurrences with respect to magnitude, time and space, but also on the uncertainties associated with the predicted values of the seismic and geometric parameters, as well as the uncertainty in the attenuation model. The uncertainty due to the attenuation equation is incorporated into the analysis through the use of random correction factors. The influence of the uncertainty resulting from the insufficient information on the seismic parameters and source geometry is introduced into the analysis by computing a mean risk curve averaged over the various alternative assumptions on the parameters and source geometry. Seismic risk analysis is carried for the city of Denizli, which is located in the seismically most active zone of Turkey. The second analysis is for Akkuyu

  15. New Madrid seismotectonic study. Activities during fiscal year 1977

    International Nuclear Information System (INIS)

    Buschbach, T.C.

    1977-10-01

    Approximately 30 highly qualified scientists are participating in a coordinated geological, geophysical, and seismological study of the area within a 200-mile radius of New Madrid, Missouri. The study is designed to define the structural setting and tectonic history of the area in order to realistically evaluate earthquake risks in the siting of nuclear facilities. The region studied includes Illinois, Indiana, Kentucky, Tennessee, Alabama, Arkansas, and Missouri. An inventory of existing data and supporting research in the area was prepared. New information from aeromagnetic, ground magnetic, and gravity surveys has been obtained, and the data are currently being processed

  16. The Madrid Train Bombings: A Decision-Making Model Analysis

    Science.gov (United States)

    2009-12-11

    3T. K. Lawson Managing Editor, ―Madrid Bombing and Attacks on Trains, Subways ,‖ U.S. Department of State, Diplomatic Security Command Center (17 March...Alfred De Montesquiou, ―Official: Al-Qaeda Like A Fast Food Franchise ‗For Terrorism‘,‖ USA Today, 7 June 2009, http://www.usatoday.com/news/world/2009...Fort Leavenworth, KS, 2007): 78; De Montesquiou, ―Official: Al- Qaeda Like A Fast Food Franchise ‗For Terrorism‘.‖ 39Wilson, ―The Evolution of al

  17. The Lusi seismic experiment: An initial study to understand the effect of seismic activity to Lusi

    Energy Technology Data Exchange (ETDEWEB)

    Karyono, E-mail: karyonosu@gmail.com [Agency for Meteorology, Climatology and Geophysics (BMKG), Jakarta (Indonesia); OSLO University (Norway); Padjadjaran University (UNPAD), Bandung (Indonesia); Mazzini, Adriano; Sugiharto, Anton [OSLO University (Norway); Lupi, Matteo [ETH Zurich (Switzerland); Syafri, Ildrem [Padjadjaran University (UNPAD), Bandung (Indonesia); Masturyono,; Rudiyanto, Ariska; Pranata, Bayu; Muzli,; Widodo, Handi Sulistyo; Sudrajat, Ajat [Agency for Meteorology, Climatology and Geophysics (BMKG), Jakarta (Indonesia)

    2015-04-24

    The spectacular Lumpur Sidoarjo (Lusi) eruption started in northeast Java on the 29 of May 2006 following a M6.3 earthquake striking the island [1,2]. Initially, several gas and mud eruption sites appeared along the reactivated strike-slip Watukosek fault system [3] and within weeks several villages were submerged by boiling mud. The most prominent eruption site was named Lusi. The Lusi seismic experiment is a project aims to begin a detailed study of seismicity around the Lusi area. In this initial phase we deploy 30 seismometers strategically distributed in the area around Lusi and along the Watukosek fault zone that stretches between Lusi and the Arjuno Welirang (AW) complex. The purpose of the initial monitoring is to conduct a preliminary seismic campaign aiming to identify the occurrence and the location of local seismic events in east Java particularly beneath Lusi.This network will locate small event that may not be captured by the existing BMKG network. It will be crucial to design the second phase of the seismic experiment that will consist of a local earthquake tomography of the Lusi-AW region and spatial and temporal variations of vp/vs ratios. The goal of this study is to understand how the seismicity occurring along the Sunda subduction zone affects to the behavior of the Lusi eruption. Our study will also provide a large dataset for a qualitative analysis of earthquake triggering studies, earthquake-volcano and earthquake-earthquake interactions. In this study, we will extract Green’s functions from ambient seismic noise data in order to image the shallow subsurface structure beneath LUSI area. The waveform cross-correlation technique will be apply to all of recordings of ambient seismic noise at 30 seismographic stations around the LUSI area. We use the dispersive behaviour of the retrieved Rayleigh waves to infer velocity structures in the shallow subsurface.

  18. The Banat seismic network: Evolution and performance

    International Nuclear Information System (INIS)

    Oros, E.

    2002-01-01

    In the Banat Seismic Region, with its important seismogenic zones (Banat and Danube), operates today the Banat Seismic Network. This network has four short period seismic stations telemetered at the Timisoara Seismological Observatory (since 1995): Siria, Banloc, Buzias and Timisoara. The stations are equipped with short-period S13 seismometers (1 second). The data recorded by the short-period stations are telemetered to Timisoara where they are digitized at 50 samples per second, with 16 bit resolution. At Timisoara works SAPS, an automated system for data acquisition and processing, which performs real-time event detection (based on Allen algorithm), discrimination between local and teleseismic events, automatic P and S waves picking, location and magnitude determination for local events and teleseisms, 'feeding' of an Automatic Data Request Manager with phases, locations and waveforms, sending of earthquake information (as phases and location), by e-mail to Bucharest. The beginning of the seismological observations in Banat is in the 1880's (Timisoara Meteorological Observatory). The first seismograph was installed in Timisoara in 1901, and its systematic observations began in 1902. The World War I interrupted its work. In 1942 Prof. I. Curea founded the Seismic Station Timisoara, and since 1967 until today this station worked into a special building. After 1972 two stations with high amplification were installed in Retezat Mts (Gura Zlata) and on Nera Valey (Susara), as a consequence of the research results. Since 1982 Buzias station began to work completing the Banat Seismic Network. Therefore, the network could detect and locate any local seismic event with M > 2.2. Moreover, up to 20 km distance from each station any seismic event could be detected over M = 0.5. The paper also presents the quality of the locations versus different local seismic sources. (author)

  19. Seismic changes industry

    International Nuclear Information System (INIS)

    Taylor, G.

    1992-01-01

    This paper discusses the growth in the seismic industry as a result of the recent increases in the foreign market. With the decline of communism and the opening of Latin America to exploration, seismic teams have moved out into these areas in support of the oil and gas industry. The paper goes on to discuss the improved technology available for seismic resolution and the subsequent use of computers to field-proof the data while the seismic team is still on-site. It also discusses the effects of new computer technology on reducing the amount of support staff that is required to both conduct and interpret seismic information

  20. Determination and Distribution of Critical Loads: Application to the Forest Soils in the Autonomous Region of Madrid; Determinacion y Distribucion de Cargas Criticas: Aplicacion a los Suelos forestales de la comunidad Autonoma de Madrid

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, M.; Schmid, T.; Rabago, I. [Ciemat, Madrid (Spain)

    2000-07-01

    The critical loads of acidity and sulphur have been determined for forest soils within the north and north-west of the Autonomous Region of Madrid. The SMB-CCE and SMB-PROFILE Steady state models have been applied using a 1 km x 1 km resolution. the forest ecosystems have been characterised according to the soil and forest type, slope and climatic data using a Geographic Information System. In order to estimate the critical loads, processes such as weathering rate of the parent material, atmospheric deposition, critical alkalinity leaching rate and nutrients absorbed by the vegetation have been considered. In general the forest soils present high critical load values for acidity and sulphur. The more sensitive zones are found in the north of the Sierra of Guadarrama. Independent of the applied methods, the results are associated to the types of soils where Leptosols have the lowest. Cambisoles and Regosoles intermediate and luvisoles the most elevated values. (Author) 40 refs.

  1. [Batas Nómadas in Madrid Salud: art and artists in professional community health teams].

    Science.gov (United States)

    Castillejo, Mar; Fernández-Cedena, Jorge; Siles, Silvia; Claver, María Dolores; Ávila, Noemí

    2018-06-14

    This article describes the strategy of incorporating artists into the teams of community health in the city of Madrid, specifically in the Madrid Salud Centers. The artistic colletive, Batas Nómadas, formed by three artists expertized in visual arts, has developed performances and participatory aproach to explain the incorporation of art and artists in these teams of professionals of Madrid Salud. Batas Nómadas has carried out sessions in 14 work teams of the Madrid Salud Centers and has collected data in a creative way from the 179 professionals that have participated in these sessions. These actions have shown some needs in community health, and have noticed a meaningful reflection on the usefulness of the art to develop participative strategies into the Madrid Salud teams. Copyright © 2018. Publicado por Elsevier España, S.L.U.

  2. Comparison between seismic and domestic risk in moderate seismic hazard prone region: the Grenoble City (France test site

    Directory of Open Access Journals (Sweden)

    F. Dunand

    2012-02-01

    Full Text Available France has a moderate level of seismic activity, characterized by diffuse seismicity, sometimes experiencing earthquakes of a magnitude of more than 5 in the most active zones. In this seismicity context, Grenoble is a city of major economic and social importance. However, earthquakes being rare, public authorities and the decision makers are only vaguely committed to reducing seismic risk: return periods are long and local policy makers do not have much information available. Over the past 25 yr, a large number of studies have been conducted to improve our knowledge of seismic hazard in this region. One of the decision-making concerns of Grenoble's public authorities, as managers of a large number of public buildings, is to know not only the seismic-prone regions, the variability of seismic hazard due to site effects and the city's overall vulnerability, but also the level of seismic risk and exposure for the entire city, also compared to other natural or/and domestic hazards. Our seismic risk analysis uses a probabilistic approach for regional and local hazards and the vulnerability assessment of buildings. Its applicability to Grenoble offers the advantage of being based on knowledge acquired by previous projects conducted over the years. This paper aims to compare the level of seismic risk with that of other risks and to introduce the notion of risk acceptability in order to offer guidance in the management of seismic risk. This notion of acceptability, which is now part of seismic risk consideration for existing buildings in Switzerland, is relevant in moderately seismic-prone countries like France.

  3. Seismic Imaging of Mantle Plumes

    Science.gov (United States)

    Nataf, Henri-Claude

    The mantle plume hypothesis was proposed thirty years ago by Jason Morgan to explain hotspot volcanoes such as Hawaii. A thermal diapir (or plume) rises from the thermal boundary layer at the base of the mantle and produces a chain of volcanoes as a plate moves on top of it. The idea is very attractive, but direct evidence for actual plumes is weak, and many questions remain unanswered. With the great improvement of seismic imagery in the past ten years, new prospects have arisen. Mantle plumes are expected to be rather narrow, and their detection by seismic techniques requires specific developments as well as dedicated field experiments. Regional travel-time tomography has provided good evidence for plumes in the upper mantle beneath a few hotspots (Yellowstone, Massif Central, Iceland). Beneath Hawaii and Iceland, the plume can be detected in the transition zone because it deflects the seismic discontinuities at 410 and 660 km depths. In the lower mantle, plumes are very difficult to detect, so specific methods have been worked out for this purpose. There are hints of a plume beneath the weak Bowie hotspot, as well as intriguing observations for Hawaii. Beneath Iceland, high-resolution tomography has just revealed a wide and meandering plume-like structure extending from the core-mantle boundary up to the surface. Among the many phenomena that seem to take place in the lowermost mantle (or D''), there are also signs there of the presence of plumes. In this article I review the main results obtained so far from these studies and discuss their implications for plume dynamics. Seismic imaging of mantle plumes is still in its infancy but should soon become a turbulent teenager.

  4. Seismic hazard studies in Egypt

    Directory of Open Access Journals (Sweden)

    Abuo El-Ela A. Mohamed

    2012-12-01

    Full Text Available The study of earthquake activity and seismic hazard assessment of Egypt is very important due to the great and rapid spreading of large investments in national projects, especially the nuclear power plant that will be held in the northern part of Egypt. Although Egypt is characterized by low seismicity, it has experienced occurring of damaging earthquake effect through its history. The seismotectonic sitting of Egypt suggests that large earthquakes are possible particularly along the Gulf of Aqaba–Dead Sea transform, the Subduction zone along the Hellenic and Cyprean Arcs, and the Northern Red Sea triple junction point. In addition some inland significant sources at Aswan, Dahshour, and Cairo-Suez District should be considered. The seismic hazard for Egypt is calculated utilizing a probabilistic approach (for a grid of 0.5° × 0.5° within a logic-tree framework. Alternative seismogenic models and ground motion scaling relationships are selected to account for the epistemic uncertainty. Seismic hazard values on rock were calculated to create contour maps for four ground motion spectral periods and for different return periods. In addition, the uniform hazard spectra for rock sites for different 25 periods, and the probabilistic hazard curves for Cairo, and Alexandria cities are graphed. The peak ground acceleration (PGA values were found close to the Gulf of Aqaba and it was about 220 gal for 475 year return period. While the lowest (PGA values were detected in the western part of the western desert and it is less than 25 gal.

  5. Determination and Distribution of Critical Loads: Application to the Forest Soils in the Autonomous Region of Madrid

    International Nuclear Information System (INIS)

    Sousa, M.; Schmid, T.; Rabago, I.

    2000-01-01

    The critical loads of acidity and sulphur have been determined for forest soils within the north and northwest of the Autonomous Region of Madrid. The SMB-CCE and SMB-PROFILE steady state models have been applied using a 1 km x 1 km resolution. The forest ecosystems have been characterised according to the soil and forest type, slope and climatic data using a Geographic Information System. In order to estimate the critical loads, processes such as weathering rate of the parent material, atmospheric deposition. critical alkalinity leaching rate and nutrients absorbed by the vegetation have been considered. In general the forest soils present high critical load values for acidity and sulphur. The more sensitive zones are found in the north of the Sierra of Guadarrama. Independent of the applied methods, the results are associated to the types of soils where Leptosols have the lowest, Cambisoles and Regosoles intermediate and Luvisoles the most elevated values. (Author) 40 refs

  6. Seismic hazard in the Nation's breadbasket

    Science.gov (United States)

    Boyd, Oliver; Haller, Kathleen; Luco, Nicolas; Moschetti, Morgan P.; Mueller, Charles; Petersen, Mark D.; Rezaeian, Sanaz; Rubinstein, Justin L.

    2015-01-01

    The USGS National Seismic Hazard Maps were updated in 2014 and included several important changes for the central United States (CUS). Background seismicity sources were improved using a new moment-magnitude-based catalog; a new adaptive, nearest-neighbor smoothing kernel was implemented; and maximum magnitudes for background sources were updated. Areal source zones developed by the Central and Eastern United States Seismic Source Characterization for Nuclear Facilities project were simplified and adopted. The weighting scheme for ground motion models was updated, giving more weight to models with a faster attenuation with distance compared to the previous maps. Overall, hazard changes (2% probability of exceedance in 50 years, across a range of ground-motion frequencies) were smaller than 10% in most of the CUS relative to the 2008 USGS maps despite new ground motion models and their assigned logic tree weights that reduced the probabilistic ground motions by 5–20%.

  7. Assessment of noise exposure during commuting in the Madrid subway.

    Science.gov (United States)

    Tabacchi, M; Pavón, I; Ausejo, M; Asensio, C; Recuero, M

    2011-09-01

    Because noise-induced hearing impairment is the result not only of occupational noise exposure but also of total daily noise exposure, it is important to take the non-occupational exposure of individuals (during commuting to and from their jobs, at home, and during recreational activities) into account. Mass transit is one of the main contributors to non-occupational noise exposure. We developed a new methodology to estimate a representative commuting noise exposure. The methodology was put into practice for the Madrid subway because of all Spanish subway systems it covers the highest percentage of worker journeys (22.6%). The results of the application highlight that, for Madrid subway passengers, noise exposure level normalized to a nominal 8 hr (L(Ex,8h-cj) ) depends strongly on the type of train, the presence of squealing noise, and the public address audio system, ranging from 68.6 dBA to 72.8 dBA. These values play an important role in a more complete evaluation of a relationship between noise dose and worker health response.

  8. Centro industrial para la «Compagnie des Lampes», en Madrid

    Directory of Open Access Journals (Sweden)

    Aymerich, Manuel

    1966-02-01

    Full Text Available The second stage of this building, constructed in the Vallecas district of Madrid, includes the workshops for the manufacture of lamp ferrules, with sections for the presses, forging and heat treatment, carbonate stores, mixes, polishing, production control, and other operations. There are also loading and packing zones, offices, first aid room, dressing rooms and services. The plan distribution, and spatial arrangement of this industrial establishment exhibit a formal and functional agile dynamism that is highly becoming.Esta nueva edificación—segunda fase—, construida en Vallecas y destinada a la fabricación de casquillos, consta en esencia de las siguientes zonas: zona de taller propiamente dicha, que alberga las secciones de prensas, mecánica, fragua y tratamientos, almacén de carbonatos, mezclas, vitrita, abrillantado, control, etc.; zona de almacenes, en conexión con los muelles para carga de camiones y carros; y la zona que aloja las oficinas, enfermería, vestuarios y servicios. Tanto la distribución de la planta como la composición de volúmenes resultan de una agilidad notable, ya que, además de su movimiento formal, expresa con sinceridad la función específica de cada cuerpo.

  9. Seismic re-evaluation of Heavy Water Plant, Kota

    International Nuclear Information System (INIS)

    Parulekar, Y.M.; Reddy, G.R.; Vaze, K.K.; Kushwaha, H.S.

    2003-10-01

    This report deals with seismic re-evaluation of Heavy Water Plant, Kota. Heavy Water Plant, Kota handles considerable amount of H 2 S gas, which is very toxic. During the original design stage as per IS 1893-1966 seismic coefficient for zone-I was zero. Therefore earthquake and its effects were not considered while designing the heavy water plant structures. However as per IS 1893 (1984) the seismic coefficient for zone-I is 0.01 g. Hence seismic re-evaluation of various structures of the heavy water plant is carried out. Analysis of the heavy water plant structures was carried out for self weight, equipment load and earthquake load. Pressure loading was also considered in case of H 2 S storage tanks. Soil structure interaction effect was considered in the analysis. The combined stresses in the structures due to earthquake and dead load were checked with the allowable stresses. (author)

  10. Seismic applications in CBM exploration and development

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, S.E.; Lawton, D.C. [Calgary Univ., AB (Canada)

    2002-07-01

    This Power Point presentation reviewed seismic methods, coal seam seismology, seismology and coalbed methane (CBM) development, and time-lapse seismic imaging with reference to numerical modelling and physical testing. The issue of resolution versus detection in various seismic methods was discussed. The thinnest resolvable beds are usually about 1.0 m thick. Coal zones with thin seams can be mapped using seismic reflection, but individual seams are difficult to resolve in field data. In terms of coal seismology, it was noted that seismic surveys make it possible to identify seam thickness, field geometry, subsurface structuring and facies changes. Facies model make it possible to determine the depositional environment, coal type, coal quality and lateral continuity. Some successes in coal seismology include the Cedar Hill and Ferron fields in the San Juan Basin. Numerical modelling methods include digital dipole compressional sonic and density well logs through Ardley Coal Zone, P-wave synthetic seismograms generated in SYNTH (MATLAB), and the alteration of density/velocity values to create new seismograms. Another numerical method is to take the difference between original and altered seismograms. It was shown that dewatering causes a decrease in velocity of about 20 per cent, and a 15 per cent decrease in density. Changes as small as 5 per cent in reservoir properties can be successfully imaged. It was concluded that the identification of dewatered zones allow for optimal positioning of development wells. Further physical testing will involve wet and dry p-wave velocities, s-wave velocities will be tested, and velocities will be measured under pressure. 2 tabs., 10 figs.

  11. The Seismic Broad Band Western Mediterranean (wm) Network and the Obs Fomar Pool: Current state and Obs activities.

    Science.gov (United States)

    Pazos, Antonio; Davila, Jose Martin; Buforn, Elisa; Bezzeghoud, Mourad; Harnafi, Mimoun; Mattesini, Mauricio; Caldeira, Bento; Hanka, Winfried; El Moudnib, Lahcen; Strollo, Angelo; Roca, Antoni; Lopez de Mesa, Mireya; Dahm, Torsten; Cabieces, Roberto

    2016-04-01

    The Western Mediterranean (WM) seismic network started in 1996 as an initiative of the Royal Spanish Navy Observatory (ROA) and the Universidad Complutense de Madrid (UCM), with the collaboration of the GeoForschungsZentrum (GFZ) of Potsdam. A first broad band seismic station (SFUC) was installed close to Cádiz (South Spain). Since then, additional stations have been installed in the Ibero-Moghrebian region. In 2005, the "WM" code was assigned by the FDSN and new partners were jointed: Evora University (UEVO, Portugal), the Scientifique Institute of Rabat (ISRABAT, Morocco), and GFZ. Now days, the WM network is composed by 15 BB stations, all of them with Streckaisen STS-2 or STS-2.5 sensors, Quanterra or Earthdata digitizers and SeiscomP. Most them have co-installed a permanent geodetic GPS stations, and some them also have an accelerometer. There are 10 stations deployed in Spanish territory (5 in the Iberian peninsula, 1 in Balearic islands and 4 in North Africa Spanish places) with VSAT or Internet communications, 2 in Portugal (one of them without real time), and 3 in Morocco (2 VSAT and 1 ADSL). Additionally, 2 more stations (one in South Spain and one in Morocco) will be installed along this year. Additionally ROA has deployed a permanent real time VBB (CMG-3T: 360s) station at the Alboran Island. Due to the fact that part of the seismic activity is located at marine areas, and also because of the poor geographic azimuthal coverage at some zones provided by the land stations (specially in the SW of the San Vicente Cape area), ROA and UCM have acquired six broad band "LOBSTERN" OBS, manufactured by KUM (Kiel, Germany), conforming the OBS FOMAR pool. Three of them with CMG-40T sensor and the other with Trillium 120. These OBS were deployed along the Gibraltar strait since January to November 2014 to study the microseismicity in the Gibraltar strait area. In September 2015 FOMAR network has been deployed in SW of the San Vicente Cape for 8 months as a part of

  12. Seismological evidence for a localized mushy zone at the Earth?s inner core boundary

    OpenAIRE

    Tian, Dongdong; Wen, Lianxing

    2017-01-01

    Although existence of a mushy zone in the Earth?s inner core has been hypothesized several decades ago, no seismic evidence has ever been reported. Based on waveform modeling of seismic compressional waves that are reflected off the Earth?s inner core boundary, here we present seismic evidence for a localized 4?8?km thick zone across the inner core boundary beneath southwest Okhotsk Sea with seismic properties intermediate between those of the inner and outer core and of a mushy zone. Such a ...

  13. Seismic prediction ahead of tunnel construction using Rayleigh-waves

    OpenAIRE

    Jetschny, Stefan; De Nil, Denise; Bohlen, Thomas

    2008-01-01

    To increase safety and efficiency of tunnel constructions, online seismic exploration ahead of a tunnel can become a valuable tool. We developed a new forward looking seismic imaging technique e.g. to determine weak and water bearing zones ahead of the constructions. Our approach is based on the excitation and registration of tunnel surface-waves. These waves are excited at the tunnel face behind the cutter head of a tunnel boring machine and travel into drilling direction. Arriving at the fr...

  14. Shallow lunar structure determined from the passive seismic experiment

    International Nuclear Information System (INIS)

    Nakamura, Y.; Dorman, J.; Duennebier, F.; Lammlein, D.; Latham, G.

    1975-01-01

    Data relevant to the shallow structure of the Moon obtained at the Apollo seismic stations are compared with previously published results of the active seismic experiments. It is concluded that the lunar surface is covered by a layer of low seismic velocity (Vsub(p) approximately equal to 100 ms -1 ), which appears to be equivalent to the lunar regolith defined previously by geological observations. This layer is underlain by a zone of distinctly higher seismic velocity at all of the Apollo landing sites. The regolith thicknesses at the Apollo 11, 12, and 15 sites are estimated from the shear-wave resonance to be 4.4, 3.7, and 4.4m, respectively. These thicknesses and those determined at the other Apollo sites by the active seismic experiments appear to be correlated with the age determinations and the abundances of extra-lunar components at the sites. (Auth.)

  15. A seismic study on cracks in crystalline rock

    International Nuclear Information System (INIS)

    Israelsson, H.

    1981-07-01

    This report summarizes results from a field study with in-situ seismic measurements in crystalline rock. It was found that among a few potential seismic techniques the so called cross hole method would probably provide the most powerful capability for detecting cracks and fracture zones. By this method the area between two holes are systematically scanned by seismic raypaths. Seismic signals are generated in one hole by micro explosions and recorded in the other at various combinations of depths. A test sample of scanning data showed a rather dramatic variation of the seismic P-wave velocity (5-6 km/s). Analysis procedures like tomographic imaging was applied to this data set primarily to illustrate the kind of structural mapping such procedures can provide. (Author)

  16. Seismicity, seismic input and site effects in the Sahel-Algiers region (north Algeria)

    International Nuclear Information System (INIS)

    Harbi, A.; Maouche, S.; Oussadou, F.; Vaccari, F.; Aoudia, A.; Panza, G.F.; Benouar, D.

    2005-07-01

    Algiers city is located in a seismogenic zone. To reduce the impact of seismic risk in this capital city, a realistic modelling of the seismic ground motion using the hybrid method that combines the finite-differences method and the modal summation, is conducted. For this purpose, a complete database in terms of geological, geophysical and earthquake data is constructed. A critical re-appraisal of the seismicity of the zone (2.25 deg. E-3.50 deg. E, 36.50 deg. N-37.00 deg. N) is performed and an earthquake list, for the period 1359-2002, is compiled. The analysis of existing and newly retrieved macroseismic information allowed the definition of earthquake parameters of macroseismic events for which a degree of reliability is assigned. Geological cross-sections have been built up to model the seismic ground motion in the city, caused by the 1989 Mont-Chenoua and the 1924 Douera earthquakes; a set of synthetic seismograms and response spectral ratio is produced for Algiers. The numerical results show that the soft sediments in Algiers centre are responsible of the noticed amplification of the seismic ground motion. (author)

  17. Design experience on seismically isolated buildings

    International Nuclear Information System (INIS)

    Giuliani, G.C.

    1991-01-01

    This paper describes the practical problems associated with the structural design of seismically isolated buildings now under construction in Ancona, Italy. These structures are the first seismically isolated buildings in Italy. The Ancona region is in zone 2 of the Italian Seismic Code. It has a design acceleration of 0.07 g which corresponds to a ground surface acceleration of 0.25 g. The last significant earthquake was recorded on June 14, 1972, having a single shock-type wave with a peak acceleration of 0.53 g. Taking into account the aforesaid earthquake, the structural design of these new buildings was performed according to an acceleration spectrum which was different from the zone 2 seismic code and which provided protection for stronger ground motions. To minimize the cost of the structure, the buildings used ribbed plate decks, thus reducing the amount of material and the mass of the structures to be isolated. The design requirements, dynamic analysis performed, structural design, and practical engineering employed are reported in this paper. A comparison between the costs of a conventionally designed and a base-isolated structure is also reported. It shows a net savings of 7% for the base-isolated structure. The tests undertaken for certifying the mechanical properties of the isolators for both static and dynamic loads are also described, as is the full-scale dynamic test which is scheduled for next year (1990) for one of the completed buildings. (orig.)

  18. The new Central American seismic hazard zonation: Mutual consensus based on up to day seismotectonic framework

    Science.gov (United States)

    Alvarado, Guillermo E.; Benito, Belén; Staller, Alejandra; Climent, Álvaro; Camacho, Eduardo; Rojas, Wilfredo; Marroquín, Griselda; Molina, Enrique; Talavera, J. Emilio; Martínez-Cuevas, Sandra; Lindholm, Conrad

    2017-11-01

    Central America is one of the most active seismic zones in the World, due to the interaction of five tectonic plates (North America, Caribbean, Coco, Nazca and South America), and its internal deformation, which generates almost one destructive earthquakes (5.4 ≤ Mw ≤ 8.1) every year. A new seismological zonation for Central America is proposed based on seismotectonic framework, a geological context (tectonic and geological maps), geophysical and geodetic evidence (gravimetric maps, magnetometric, GPS observations), and previous works. As a main source of data a depurated earthquake catalog was collected covering the period from 1522 to 2015. This catalog was homogenized to a moment magnitude scale (Mw). After a careful analysis of all the integrated geological and seismological information, the seismogenic zones were established into seismic areas defined by similar patterns of faulting, seismicity, and rupture mechanism. The tectonic environment has required considering seismic zones in two particular seismological regimes: a) crustal faulting (including local faults, major fracture zones of plate boundary limits, and thrust fault of deformed belts) and b) subduction, taking into account the change in the subduction angle along the trench, and the type and location of the rupture. The seismicity in the subduction zone is divided into interplate and intraplate inslab seismicity. The regional seismic zonation proposed for the whole of Central America, include local seismic zonations, avoiding discontinuities at the national boundaries, because of a consensus between the 7 countries, based on the cooperative work of specialists on Central American seismotectonics and related topics.

  19. Estudio del comportamiento en zonas sísmicas del hormigón pretensado con refuerzo de fibras = Study of the behavior in seismic zones of reinforced prestressed concrete

    Directory of Open Access Journals (Sweden)

    Eugenia Soledad Carbel

    2016-12-01

    Full Text Available El hormigón pretensado reforzado con fibras, presenta simultáneamente las ventajas de los hormigones pretensados y de los reforzados con fibras. Se consigue un material de altas prestaciones en cuanto a su tenacidad, ductilidad y resistencia a la tracción, como así también para mejorar las características de agrietamiento y de deformación de los elementos estructurales del hormigón causados por solicitaciones sísmicas. En este trabajo se ha estudiado el comportamiento mecánico de un hormigón pretensado reforzado con fibras de acero y de poliamida , y su capacidad de resistir las grandes fuerzas de inercia causadas por las solicitaciones sísmicas. Para una evaluación comparativa se presentan ensayos de corte cíclico entre muros estructurales construidos con hormigón convencional y los reforzados con fibras, mediante modelos de histéresis. Los resultados muestran la variación de respuesta del hormigón con el tiempo, la diferencia existente con los hormigones tradicionales y la viabilidad del empleo de fibras. Comprobando que la adición de fibras en el hormigón armado convencional puede mejorar las actuaciones estructurales y funcionales, de las estructuras de hormigón relacionadas a las acciones sísmicas, a su vez las fibras de acero son más eficaces en mejorar el rendimiento de corte de PCCV que fibras de poliamida. Abstract Prestressed concrete reinforced with fibers, simultaneously presents the advantages of prestressed concrete and reinforced with fibers. It achieves a high performance material in terms of its toughness, ductility and tensile strength, as well as to improve the cracking and deformation characteristics of the structural elements of the concrete caused by seismic stresses. In this work the mechanical behavior of a prestressed concrete reinforced with steel and polyamide fibers and its ability to withstand the large forces of inertia caused by seismic stresses has been studied. For a comparative evaluation

  20. Geomorphology and seismic risk

    Science.gov (United States)

    Panizza, Mario

    1991-07-01

    The author analyses the contributions provided by geomorphology in studies suited to the assessment of seismic risk: this is defined as function of the seismic hazard, of the seismic susceptibility, and of the vulnerability. The geomorphological studies applicable to seismic risk assessment can be divided into two sectors: (a) morpho-neotectonic investigations conducted to identify active tectonic structures; (b) geomorphological and morphometric analyses aimed at identifying the particular situations that amplify or reduce seismic susceptibility. The morpho-neotectonic studies lead to the identification, selection and classification of the lineaments that can be linked with active tectonic structures. The most important geomorphological situations that can condition seismic susceptibility are: slope angle, debris, morphology, degradational slopes, paleo-landslides and underground cavities.

  1. Optimal Retrofit Scheme for Highway Network under Seismic Hazards

    Directory of Open Access Journals (Sweden)

    Yongxi Huang

    2014-06-01

    Full Text Available Many older highway bridges in the United States (US are inadequate for seismic loads and could be severely damaged or collapsed in a relatively small earthquake. According to the most recent American Society of Civil Engineers’ infrastructure report card, one-third of the bridges in the US are rated as structurally deficient and many of these structurally deficient bridges are located in seismic zones. To improve this situation, at-risk bridges must be identified and evaluated and effective retrofitting programs should be in place to reduce their seismic vulnerabilities. In this study, a new retrofit strategy decision scheme for highway bridges under seismic hazards is developed and seamlessly integrate the scenario-based seismic analysis of bridges and the traffic network into the proposed optimization modeling framework. A full spectrum of bridge retrofit strategies is considered based on explicit structural assessment for each seismic damage state. As an empirical case study, the proposed retrofit strategy decision scheme is utilized to evaluate the bridge network in one of the active seismic zones in the US, Charleston, South Carolina. The developed modeling framework, on average, will help increase network throughput traffic capacity by 45% with a cost increase of only $15million for the Mw 5.5 event and increase the capacity fourfold with a cost of only $32m for the Mw 7.0 event.

  2. Red Palinocam: vigilancia en Madrid del polen aerovagante

    Directory of Open Access Journals (Sweden)

    Patricia Cervigón Morales

    2005-12-01

    Full Text Available El Programa Regional de Control y Prevención del Asma surge en el año 1992. El programa abordaba una estrategia con cuatro grandes áreas, entre ellas la Vigilancia Ambiental, que en el año 1993 formalizó la Red Palinológica de la Comunidad de Madrid (Red Palinocam. La red se constituye mediante la creación de un comité de expertos, coordinado desde el Instituto de Salud Pública, bajo la dirección técnica de la Facultad de Farmacia de la Universidad Complutense y está integrado por representantes de cada una de las instituciones involucradas. El marco jurídico se completa con acuerdos firmados con los ayuntamientos y con un convenio de colaboración entre la Universidad Complutense de Madrid y la Consejería de Sanidad y Consumo.El objetivo prioritario, basado en la red de muestreo de polen para el territorio de la Comunidad de Madrid, es el conocimiento del contenido polínico de su atmósfera que incide sobre la población afectada de polinosis en cada zona de nuestra área geográfica y en cada momento del año, datos de gran interés desde Salud Pública.La Red Palinocam constituye una herramienta útil en Salud Pública, proporcionando información puntual, a través de Internet y del Servicio de Información Telefónica, durante todo el año de los muestreos aerobiológicos realizados. Así las personas que sufren problemas de alergia y los profesionales sanitarios que se encargan de sus cuidados y los distintos medios de comunicación, pueden conocer los tipos polínicos más frecuentes en cada momento y su concentración en el aire ambiente.

  3. Piedmont seismic reflection study: A program integrated with tectonics to probe the cause of eastern seismicity

    Energy Technology Data Exchange (ETDEWEB)

    Glover, L. III; Coruh, C.; Costain, J.K.; Bollinger, G.A. (Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Geological Sciences)

    1992-03-01

    A new tectonic model of the Appalachian orogen indicates that one, not two or more, terrane boundaries is present in the Piedmont and Blue Ridge of the central and southern Appalachians. This terrane boundary is the Taconic suture, it has been transported in the allochthonous Blue Ridge/Piedmont crystalline thrust nappe, and it is repeated at the surface by faulting and folding associated with later Paleozoic orogenies. The suture passes through the lower crust and lithosphere somewhere east of Richmond. It is spatially associated with seismicity in the central Virginia seismic zone, but is not conformable with earthquake focal planes and appears to have little causal relation to their localization.

  4. New seismic sources parameterization in El Salvador. Implications to seismic hazard.

    OpenAIRE

    Alonso-Henar, Jorge; Staller, A.; Martínez Díaz, José J.; Benito, Belén; Álvarez Gómez, José Antonio; Canora Catalán, Carolina

    2014-01-01

    El Salvador is located at the pacific active margin of Central America, here, the subduction of the Cocos Plate under the Caribbean Plate at a rate of 80 mm/yr is the main seismic source. Although the seismic sources located in the Central American Volcanic Arc have been responsible for some of the most damaging earthquakes in El Salvador. The El Salvador Fault Zone is the main geological structure in El Salvador and accommodates 14 mm/yr of horizontal displacement between the Caribbean Plate...

  5. Signal-to-noise ratio application to seismic marker analysis and fracture detection

    Science.gov (United States)

    Xu, Hui-Qun; Gui, Zhi-Xian

    2014-03-01

    Seismic data with high signal-to-noise ratios (SNRs) are useful in reservoir exploration. To obtain high SNR seismic data, significant effort is required to achieve noise attenuation in seismic data processing, which is costly in materials, and human and financial resources. We introduce a method for improving the SNR of seismic data. The SNR is calculated by using the frequency domain method. Furthermore, we optimize and discuss the critical parameters and calculation procedure. We applied the proposed method on real data and found that the SNR is high in the seismic marker and low in the fracture zone. Consequently, this can be used to extract detailed information about fracture zones that are inferred by structural analysis but not observed in conventional seismic data.

  6. Sobre la inestabilidad de terrenos arenosos en túneles de Madrid perforados con tuneladora

    OpenAIRE

    Arnaiz Ronda, Manuel

    2011-01-01

    En la presente Memoria se presentan varias investigaciones de carácter técnico sobre los problemas de inestabilidad en túneles perforados con tuneladoras E.P.B. en los suelos arenosos de Madrid. Los principales estudios desarrollados son los siguientes: Análisis de las propiedades geotécnicas de Madrid, con especial consideración de los suelos arenosos (de bajo contenido de finos). Como resultado de estos estudios se propone una nueva clasificación de los suelos de Madrid, desde el punto de v...

  7. The SO2 pollution in Madrid: Pt. 2

    International Nuclear Information System (INIS)

    Finzi, G.; Garcia, R.; Hernandez, E.

    1983-01-01

    In this work, two different stochastic models will be considered, both oriented to the real-time forecast of daily SO 2 pollution in Madrid. The first one a ''black-box'' model, in which the input-output transfer function is identified by means of the methodology given by Box and Jenkins. The second one is a ''grey-box'' model with a simple reasonable structure in accordance with the physical laws of the phenomena. Moreover, its parameters can assume different values according to the different meteorological synoptic classes defined in part I. The comparison between the performance of the two models shows that the second one is more effective in predicting the critical pollution values

  8. Living (and work of Peruvian immigrants in Madrid

    Directory of Open Access Journals (Sweden)

    G. Pérez Pérez

    2016-10-01

    Full Text Available The present article is based on the analysis of the information obtained by means of a statistical analysis of a survey conduct among 110 Peruvian immigrants in Madrid. The living conditions of these workers are presented under a series of headings which include the job sectors in which they settle, various aspects of their working conditions and salaries, dwellings, leisure time activities, contact with their country of origin and the strength of their associationism. Previously, a sociodemographic description of the sample in set out based on an analysis of their distribution by age, sex, level of education and other variables of interest such as when and how they came to Spain or their legal situation.

  9. Áreas vulnerables en el centro de Madrid

    Directory of Open Access Journals (Sweden)

    Agustín Hernández Aja

    2007-07-01

    This document shows an vulnerability analysis of the central area of Madrid taken it as the field of APE-00.01. Its objective is to delimit “vulnerable areas” so there can be evaluated the opportunities for interve trough them and then define the best tools in detriment of their vulnerability reasons. To determinate those areas we have developed a sociodemographic analysis where we have found those units of population with vulnerable values. Once determinated, we have synthetize them to define them as easy drafts that makes understandable the work area for later on establish a vulnerable areas catalogue with spatial homogeneity and significant size. The basic nucleus of the análisis has been the sociodemographic fact, based on homogeneus data sources for all the area so they could be referenced to specific spacial areas. In each case has been advised other possible indicators of vulnerability including a signifier selection of thrm on the fifth chapter.

  10. [Health vulnerability mapping in the Community of Madrid (Spain)].

    Science.gov (United States)

    Ramasco-Gutiérrez, Milagros; Heras-Mosteiro, Julio; Garabato-González, Sonsoles; Aránguez-Ruiz, Emiliano; Aguirre Martín-Gil, Ramón

    The Public Health General Directorate of Madrid has developed a health vulnerability mapping methodology to assist regional social health teams in health planning, prioritisation and intervention based on a model of social determinants of health and an equity approach. This process began with the selection of areas with the worst social indicators in health vulnerability. Then, key stakeholders of the region jointly identified priority areas of intervention and developed a consensual plan of action. We present the outcomes of this experience and its connection with theoretical models of asset-based community development, health-integrated georeferencing systems and community health interventions. Copyright © 2016 SESPAS. Publicado por Elsevier España, S.L.U. All rights reserved.

  11. El Abasto de Pan en el Madrid del Siglo XVII

    Directory of Open Access Journals (Sweden)

    José Ignacio ANDRÉS UCENDO

    2012-12-01

    Full Text Available El mercado del pan era el más importante de los mercados de abastos, pero también el que contaba con el más complejo sistema de intervención. Los objetivos de la política de abastos eran asegurar un suministro continuo a precios estables y moderados.Los instrumentos incluían la regulación de los precios del grano y el pan, la provisión directa a través del pósito municipal y, en el caso de la corte, el pan de registro. En este trabajo examinamos la política de tasas, las disposiciones del gobierno y el comportamiento de los precios del pan en Madrid y del trigo en los mercados de origen.

  12. Burar seismic station: evaluation of seismic performance

    International Nuclear Information System (INIS)

    Ghica, Daniela; Popa, Mihaela

    2005-01-01

    A new seismic monitoring system, the Bucovina Seismic Array (BURAR), has been established since July 2002, in the Northern part of Romania, in a joint effort of the Air Force Technical Applications Center, USA, and the National Institute for Earth Physics (NIEP), Romania. The small-aperture array consists of 10 seismic sensors (9 vertical short-period and one three-component broad band) located in boreholes and distributed in a 5 x 5 km 2 area. At present, the seismic data are continuously recorded by the BURAR and transmitted in real-time to the Romanian National Data Center in Bucharest and National Data Center of the USA, in Florida. Based on the BURAR seismic information gathered at the National Data Center, NIEP (ROM N DC), in the August 2002 - December 2004 time interval, analysis and statistical assessments were performed. Following the preliminary processing of the data, several observations on the global performance of the BURAR system were emphasized. Data investigation showed an excellent efficiency of the BURAR system particularly in detecting teleseismic and regional events. Also, a statistical analysis for the BURAR detection capability of the local Vrancea events was performed in terms of depth and magnitude for the year 2004. The high signal detection capability of the BURAR resulted, generally, in improving the location solutions for the Vrancea seismic events. The location solution accuracy is enhanced when adding BURAR recordings, especially in the case of low magnitude events (recorded by few stations). The location accuracy is increased, both in terms of constraining hypocenter depth and epicentral coordinates. Our analysis certifies the importance of the BURAR system in NIEP efforts to elaborate seismic bulletins. Furthermore, the specific procedures for array data processing (beam forming, f-k analysis) increase significantly the signal-to-noise ratio by summing up the coherent signals from the array components, and ensure a better accuracy

  13. BANCA PRIVADA Y VIVIENDA USADA EN LA CIUDAD DE MADRID

    Directory of Open Access Journals (Sweden)

    Víctor Jiménez Barrado

    2016-01-01

    Full Text Available El número de viviendas usadas en poder de los bancos ha aumentado de forma notable en los últimos diez años como consecuencia de la crisis económica e hipotecaria. El considerable incremento del paquete de activos tóxicos inmobiliarios (más del 36% entre el año 2012 y 2015 procede, en buena medida, de los impagos a la banca por parte de las familias. La ciudad de Madrid es una de las poblaciones más afectadas por este fenómeno, en la que se acumulan los desahucios día tras día. El presente estudio cuantifica y analiza, a través de la información que facilitan las inmobiliarias de las cinco principales entidades bancarias del país, esta bolsa de viviendas de segunda mano en la capital española. La localización de las mismas dentro del núcleo urbano permite conocer el grado de afectación por distritos. Por otro lado, nos hemos servido de la base de datos socioeconómicos de la Administración Local para determinar la incidencia social del posicionamiento de la banca privada. El análisis espacial a través de Sistemas de Información Geográfica ha revelado comportamientos anómalos de la banca en relación al mercado de compra-venta de viviendas usadas en la ciudad de Madrid.

  14. Seismic and Geodetic Monitoring of the Nicoya, Costa Rica, Seismic Gap

    Science.gov (United States)

    Protti, M.; Gonzalez, V.; Schwartz, S.; Dixon, T.; Kato, T.; Kaneda, Y.; Simila, G.; Sampson, D.

    2007-05-01

    The Nicoya segment of the Middle America Trench has been recognized as a mature seismic gap with potential to generate a large earthquake in the near future (it ruptured with large earthquakes in 1853, 1900 and 1950). Low level of background seismicity and fast crustal deformation of the forearc are indicatives of strong coupling along the plate interface. Given its high seismic potential, the available data and especially the fact that the Nicoya peninsula extends over large part of the rupture area, this gap was selected as one of the two sites for a MARGINS-SEIZE experiment. With the goal of documenting the evolution of loading and stress release along this seismic gap, an international effort involving several institutions from Costa Rica, the United States and Japan is being carried out for over a decade in the region. This effort involves the installation of temporary and permanent seismic and geodetic networks. The seismic network includes short period, broad band and strong motion instruments. The seismic monitoring has provided valuable information on the geometry and characteristics of the plate interface. The geodetic network includes temporary and permanent GPS stations as well as surface and borehole tiltmeters. The geodetic networks have helped quantify the extend and degree of coupling. A continuously recording, three- station GPS network on the Nicoya Peninsula, Costa Rica, recorded what we believe is the first slow slip event observed along the plate interface of the Costa Rica subduction zone. We will present results from these monitoring networks. Collaborative international efforts are focused on expanding these seismic and geodetic networks to provide improved resolution of future creep events, to enhanced understanding of the mechanical behavior of the Nicoya subduction segment of the Middle American Trench and possibly capture the next large earthquake and its potential precursor deformation.

  15. From Geodetic Imaging of Seismic and Aseismic Fault Slip to Dynamic Modeling of the Seismic Cycle

    Science.gov (United States)

    Avouac, Jean-Philippe

    2015-05-01

    Understanding the partitioning of seismic and aseismic fault slip is central to seismotectonics as it ultimately determines the seismic potential of faults. Thanks to advances in tectonic geodesy, it is now possible to develop kinematic models of the spatiotemporal evolution of slip over the seismic cycle and to determine the budget of seismic and aseismic slip. Studies of subduction zones and continental faults have shown that aseismic creep is common and sometimes prevalent within the seismogenic depth range. Interseismic coupling is generally observed to be spatially heterogeneous, defining locked patches of stress accumulation, to be released in future earthquakes or aseismic transients, surrounded by creeping areas. Clay-rich tectonites, high temperature, and elevated pore-fluid pressure seem to be key factors promoting aseismic creep. The generally logarithmic time evolution of afterslip is a distinctive feature of creeping faults that suggests a logarithmic dependency of fault friction on slip rate, as observed in laboratory friction experiments. Most faults can be considered to be paved with interlaced patches where the friction law is either rate-strengthening, inhibiting seismic rupture propagation, or rate-weakening, allowing for earthquake nucleation. The rate-weakening patches act as asperities on which stress builds up in the interseismic period; they might rupture collectively in a variety of ways. The pattern of interseismic coupling can help constrain the return period of the maximum- magnitude earthquake based on the requirement that seismic and aseismic slip sum to match long-term slip. Dynamic models of the seismic cycle based on this conceptual model can be tuned to reproduce geodetic and seismological observations. The promise and pitfalls of using such models to assess seismic hazard are discussed.

  16. Crustal seismicity and active fault system in the SE of Romania

    International Nuclear Information System (INIS)

    Raileanu, V; Bala, A.; Radulian, M.; Popescu, E.; Mateciuc, D.; Popa, M.; Dinu, C.; Diaconescu, V.

    2007-01-01

    Romania is known as a country with a high seismicity located in the Vrancea region where 2-3 strong intermediate depth earthquakes/century generate great damages and casualties. A moderate crustal seismicity is also observed in other zones of the country, with events having a moderate magnitude but sometimes with important economic and social effects on the locale scale. The crustal seismogenic zones are located in front of the Eastern Carpathian Bend, South Carpathians, Dobrogea, Banat, Crisana and Maramures regions. The SE part of Romania comprises some of the most active crustal seismic sources that generated earthquakes up to Mw=6.5 concentrated in more zones, namely: Vrancea crustal domain, E Vrancea zone that is overlapped on the Focsani basin, Barlad and Predobrogean depressions along with the North Dobrogea Orogen, Intramoesian and Shabla (Bulgaria) zones and Fagaras-Campulung-Sinaia zone. (authors)

  17. Seismic activity parameters of the Finnish potential repository sites

    International Nuclear Information System (INIS)

    Saari, J.

    2000-10-01

    Posiva Oy has started a project for estimating the possible earthquake induced rock movements on the deposition holes containing canisters of spent nuclear fuel. These estimates will be made for the four investigation sites, Romuvaara, Kivetty, Olkiluoto and Haestholmen. This study deals with the current and future seismicity associated with the above mentioned sites. Seismic belts that participate the seismic behaviour of the studied sites have been identified and the magnitude-frequency distributions of these belts have been estimated. The seismic activity parameters of the sites have been deduced from the characteristics of the seismic belts in order to forecast the seismicity during the next 100,000 years. The report discusses the possible earthquakes induced by future glaciation. The seismic interpretation seems to indicate that the previous postglacial faults in Finnish Lapland have been generated in compressional environment. The orientation of the rather uniform compression has been NW-SE, which coincide with the current stress field. It seems that, although the impact of postglacial crustal rebound must have been significant, the impact of plate tectonics has been dominant. A major assumption of this study has been that future seismicity will generally resemble the current seismicity. However, when the postglacial seismicity is concerned, the magnitude-frequency distribution is likely different and the expected maximum magnitude will be higher. Maximum magnitudes of future postglacial earthquakes have been approximated by strain release examinations. Seismicity has been examined within the framework of the lineament maps, in order to associate the future significant earthquakes with active fault zones in the vicinity of the potential repository sites. (orig.)

  18. Seismicity Structure of the Downgoing Nazca Slab in Northern Chile

    Science.gov (United States)

    Sippl, C.; Schurr, B.

    2017-12-01

    We applied an automatized earthquake detection and location algorithm to 8 years of continuous seismic data from the IPOC network in Northern Chile, located in the forearc between about 18.5°S and 24°S. The resulting seismicity catalog contains more than 113k double-difference relocated earthquake hypocenters and features a completeness magnitude around 2.8. Despite the occurrence of two megathrust earthquakes with vigorous aftershock seismicity in the studied time period (the 2007 Tocopilla and the 2014 Iquique earthquakes), >60% of the retrieved seismicity is located in a highly active band of intermediate-depth earthquakes (80-120 km deep) within the downgoing Nazca slab.We obtain a triple seismic zone in the updip part of the slab, with the three parallel dipping planes corresponding to the plate interface, the oceanic Moho (ca. 8 km below the interface) and a third band in the mantle lithosphere 26-28 km beneath the slab top. The plate interface seismicity terminates abruptly at a depth of 55 km. At about 80-90 km depth, the remaining two planes of seismicity then merge into the single, 20 km thick cluster of vigorous seismicity mentioned above, which terminates at 120 km depth. This cluster is located directly beneath the volcanic arc and shows a pronounced kink in the slab dipping angle. Intra-slab seismicity is most likely related to metamorphic dehydration reactions, hence our high-resolution earthquake distribution can be considered a map of metamorphic reactions (although a possibly incomplete one, since not all reactions necessarily invoke seismicity). By correlating this distribution with isotherms from thermal models as well as geophysical imaging results from previous studies, we attempt to get a glimpse at the processes that produce the different patches of intraslab seismicity at intermediate depths.

  19. Investigation on the Combined Use of Ground Penetrating Radar, Cone Penetrometer and High Resolution Seismic Data for Near Surface and Vadose Zone Characterization in the A/M Area of the Savannah River Site, South Carolina

    International Nuclear Information System (INIS)

    Wyatt, D.E.; Cumbest, R.J.; Aadland, R.K.; Syms, F.H.; Stephenson, D.E.; Sherrill, J.C.

    1997-06-01

    This study compares data from Cone Penetrometer Tests (CPT), high resolution surface reflection seismic (HRS) data and ground penetrating radar (GPR) data in the upper 120 feet (40 meters) of the A/M Area, Upper Three Runs Watershed at the Savannah River Site in South Carolina. The CPT, GPR, and HRS data were obtained along the Silverton Road in the western sector of the A/M Area groundwater plume, and adjacent to Geophysical Correlation Boring number-sign 1 (GCB-1). This location allows for multiple correlations to be made between the various data sources, and supports shallow investigations for near surface affects of the Crackerneck Fault, a major structural feature in the area. Borehole geophysical data from GCB-1 were used to provide subsurface constraints on the CPT, GPR, and HRS data. core data, natural gamma ray, spectral gamma data, multi-level induction resistivity, density and sonic data were utilized to distinguish clays, sands and silts. The CPT data provided tip bearing and sleeve stress, as an indicator of stratigraphy. Reflection seismic data provided continuous subsurface profiles of key marker horizons. Ground Penetrating Radar provided information on shallow subsurface geological features. Conclusions from this study suggest that there is a high degree of correlation between the CPT and borehole geophysical data, specifically, the Friction Ratio and gamma/spectral gamma curves. The Upland/Tobacco Road, Tobacco Road/Dry Branch, Dry Branch/Santee, Santee/Warley Hill and the Warley Hill/Congaree contacts are discernible. From these contacts it is possible to map structural relationships in the shallow subsurface that are tied to regional data. Because formation contacts are discernible, CPT, HRS, GPR, and geophysical log intra-formational anomalies are mappable. These features allow for stratigraphic and facies mapping using the GPR and HRS data for continuity and the CPT and geophysical data for lithofacies analysis. It is possible to use the

  20. Seismic signatures of the Lodgepole fractured reservoir in Utah-Wyoming overthrust belt

    Energy Technology Data Exchange (ETDEWEB)

    Parra, J.; Collier, H.; Angstman, B.

    1997-08-01

    In low porosity, low permeability zones, natural fractures are the primary source of permeability which affect both production and injection of fluids. The open fractures do not contribute much to porosity, but they provide an increased drainage network to any porosity. An important approach to characterizing the fracture orientation and fracture permeability of reservoir formations is one based upon the effects of such conditions on the propagation of acoustic and seismic waves in the rock. We present the feasibility of using seismic measurement techniques to map the fracture zones between wells spaced 2400 ft at depths of about 1000 ft. For this purpose we constructed computer models (which include azimuthal anisotropy) using Lodgepole reservoir parameters to predict seismic signatures recorded at the borehole scale, crosswell scale, and 3 D seismic scale. We have integrated well logs with existing 2D surfaces seismic to produce petrophysical and geological cross sections to determine the reservoir parameters and geometry for the computer models. In particular, the model responses are used to evaluate if surface seismic and crosswell seismic measurements can capture the anisotropy due to vertical fractures. Preliminary results suggested that seismic waves transmitted between two wells will propagate in carbonate fracture reservoirs, and the signal can be received above the noise level at the distance of 2400 ft. In addition, the large velocities contrast between the main fracture zone and the underlying unfractured Boundary Ridge Member, suggested that borehole reflection imaging may be appropriate to map and fracture zone thickness variation and fracture distributions in the reservoir.

  1. Microseismic monitoring of CO2-injection-induced seismicity

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Huang, Lianjie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-10-03

    This presentation's Objectives: Studying moment tensors of microseismic sources; Imaging fracture zones and subsurface structure; Obtaining three-dimension seismic velocity model and improved moment tensors.

  2. Experimental hematology: theoretical and practical course, Madrid 31th may to 4th june 1993

    International Nuclear Information System (INIS)

    Bueren, J.A.; Tejero Ortega, C.

    1993-01-01

    This book contains the lectures of hematology course held in Madrid. The main scope of conferences are: 1.- Hematopoiesis: regulation, growing ionizing radiations, damage and radiation effects. 2.- Radioprotection: stem cells of mouse 3.- Genetic: hematopoietic pathology 4.- Stem cells

  3. Global seismic inversion as the next standard step in the processing sequence

    Energy Technology Data Exchange (ETDEWEB)

    Maver, Kim G.; Hansen, Lars S.; Jepsen, Anne-Marie; Rasmussen, Klaus B.

    1998-12-31

    Seismic inversion of post stack seismic data has until recently been regarded as a reservoir oriented method since the standard inversion techniques rely on extensive well control and a detailed user derived input model. Most seismic inversion techniques further requires a stable wavelet. As a consequence seismic inversion is mainly utilised in mature areas focusing of specific zones only after the seismic data has been interpreted and is well understood. By using an advanced 3-D global technique, seismic inversion is presented as the next standard step in the processing sequence. The technique is robust towards noise within the seismic data, utilizes a time variant wavelet, and derives a low frequency model utilizing the stacking velocities and only limited well control. 4 figs.

  4. Impacto de las autopistas de circunvalación en la accesibilidad del área metropolitana de Madrid

    Directory of Open Access Journals (Sweden)

    García Palomares, Juan Carlos

    2001-06-01

    Full Text Available One of the traditional aplications of the Geographic Information Systems has been the study of territorial impact on the construccion of new transport infrastructure through the accessibility indicator calculus. In this article it has been applied the SIG to the impact study on the building of new orbital motorways by the accessibility of different job groups to Madrid metropolitan area. In a period in wich we are involved in an intense metropolitan reestructuration process, with all the complications derived, it's very important to know how does it change the accessibility, according not only to the transport infrastructures changes but to the activities distribution, in time to apply political resolutions that connect transport and ground use in order to promote a supportable ovility model.

    [es] Una de las aplicaciones que tradicionalmente se ha dado a los Sistemas de Información Geográfica es el estudio de los impactos territoriales que tiene la construcción de nuevas infraestructuras de transporte a través del cálculo de indicadores de accesibilidad. En este artículo se han aplicado los S.I.G. al estudio del impacto de la construcción de nuevas autopistas de circunvalación en la accesibilidad a diferentes grupos de empleos en el área metropolitana de Madrid. En un momento en el que nos encontramos inmersos en un intenso proceso de reestructuración metropolitana, con los problemas que el mismo ocasiona, conocer cómo cambia la accesibilidad en función tanto de los cambios en las infraestructuras de transporte como de la propia distribución de las actividades, es muy importante a la hora de determinar políticas que relacionen transporte y uso del suelo, con el objetivo de potenciar un modelo sostenible de la movilidad. [fr] L'impact des autoroutes de circouvalavation sur l'accessibilité de la zone métropolitaine de Madrid. Une des applications qui s'a donné aux systems d´information geografique, c'est l

  5. The Great Maule earthquake: seismicity prior to and after the main shock from amphibious seismic networks

    Science.gov (United States)

    Lieser, K.; Arroyo, I. G.; Grevemeyer, I.; Flueh, E. R.; Lange, D.; Tilmann, F. J.

    2013-12-01

    The Chilean subduction zone is among the seismically most active plate boundaries in the world and its coastal ranges suffer from a magnitude 8 or larger megathrust earthquake every 10-20 years. The Constitución-Concepción or Maule segment in central Chile between ~35.5°S and 37°S was considered to be a mature seismic gap, rupturing last in 1835 and being seismically quiet without any magnitude 4.5 or larger earthquakes reported in global catalogues. It is located to the north of the nucleation area of the 1960 magnitude 9.5 Valdivia earthquake and to the south of the 1928 magnitude 8 Talca earthquake. On 27 February 2010 this segment ruptured in a Mw=8.8 earthquake, nucleating near 36°S and affecting a 500-600 km long segment of the margin between 34°S and 38.5°S. Aftershocks occurred along a roughly 600 km long portion of the central Chilean margin, most of them offshore. Therefore, a network of 30 ocean-bottom-seismometers was deployed in the northern portion of the rupture area for a three month period, recording local offshore aftershocks between 20 September 2010 and 25 December 2010. In addition, data of a network consisting of 33 landstations of the GeoForschungsZentrum Potsdam were included into the network, providing an ideal coverage of both the rupture plane and areas affected by post-seismic slip as deduced from geodetic data. Aftershock locations are based on automatically detected P wave onsets and a 2.5D velocity model of the combined on- and offshore network. Aftershock seismicity analysis in the northern part of the survey area reveals a well resolved seismically active splay fault in the accretionary prism of the Chilean forearc. Our findings imply that in the northernmost part of the rupture zone, co-seismic slip most likely propagated along the splay fault and not the subduction thrust fault. In addition, the updip limit of aftershocks along the plate interface can be verified to about 40 km landwards from the deformation front. Prior to

  6. Seismic texture classification. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Vinther, R.

    1997-12-31

    The seismic texture classification method, is a seismic attribute that can both recognize the general reflectivity styles and locate variations from these. The seismic texture classification performs a statistic analysis for the seismic section (or volume) aiming at describing the reflectivity. Based on a set of reference reflectivities the seismic textures are classified. The result of the seismic texture classification is a display of seismic texture categories showing both the styles of reflectivity from the reference set and interpolations and extrapolations from these. The display is interpreted as statistical variations in the seismic data. The seismic texture classification is applied to seismic sections and volumes from the Danish North Sea representing both horizontal stratifications and salt diapers. The attribute succeeded in recognizing both general structure of successions and variations from these. Also, the seismic texture classification is not only able to display variations in prospective areas (1-7 sec. TWT) but can also be applied to deep seismic sections. The seismic texture classification is tested on a deep reflection seismic section (13-18 sec. TWT) from the Baltic Sea. Applied to this section the seismic texture classification succeeded in locating the Moho, which could not be located using conventional interpretation tools. The seismic texture classification is a seismic attribute which can display general reflectivity styles and deviations from these and enhance variations not found by conventional interpretation tools. (LN)

  7. Micro-seismicity and seismic moment release within the Coso Geothermal Field, California

    Science.gov (United States)

    Kaven, Joern; Hickman, Stephen H.; Davatzes, Nicholas C.

    2014-01-01

    We relocate 16 years of seismicity in the Coso Geothermal Field (CGF) using differential travel times and simultaneously invert for seismic velocities to improve our knowledge of the subsurface geologic and hydrologic structure. We expand on our previous results by doubling the number of relocated events from April 1996 through May 2012 using a new field-wide 3-D velocity model. Relocated micro-seismicity sharpens in many portions of the active geothermal reservoir, likely defining large-scale fault zones and fluid pressure compartment boundaries. However, a significant fraction of seismicity remains diffuse and does not cluster into sharply defined structures, suggesting that permeability is maintained within the reservoir through distributed brittle failure. The seismic velocity structure reveals heterogeneous distributions of compressional (Vp) and shear (Vs) wave speed, with Vs generally higher in the Main Field and East Flank and Vp remaining relatively uniform across the CGF, but with significant local variations. The Vp/Vs ratio appears to outline the two main producing compartments of the reservoir at depths below mean ground level of approximately 1 to 2.5 km, with a ridge of relatively high Vp/Vs separating the Main Field from the East Flank. Detailed analyses of spatial and temporal variations in earthquake relocations and cumulative seismic moment release in the East Flank reveal three regions with persistently high rates of seismic activity. Two of these regions exhibit sharp, stationary boundaries at the margins of the East Flank that likely represent barriers to fluid flow and advective heat transport. However, seismicity and moment release in a third region at the northern end of the East Flank spread over time to form an elongated NE to SW structure, roughly parallel both to an elongated cluster of seismicity at the southern end of the East Flank and to regional fault traces mapped at the surface. Our results indicate that high

  8. Gymkhana Matemática para estudiantes universitarios por la Ciudad Universitaria de Madrid

    Directory of Open Access Journals (Sweden)

    Mª Dolores López González

    2011-10-01

    Full Text Available Este artículo recoge la experiencia del Grupo de Innovación Educativa(GIE “Pensamiento Matemático” de la Universidad Politécnica de Madrid(UPM en la realización de una Gymkhana Matemática por el campus deMoncloa en la Ciudad Universitaria de Madrid que tuvo lugar el 30 de septiembre de 2011.

  9. Regional water footprint and water management: the case of Madrid region (Spain)

    OpenAIRE

    Soler Rovira, José; Arroyo Sanz, Juan Manuel; Conde Marcos, Hugo; Sanz Zudaire, Carlos; Mesa Moreno, Alfredo; Gil Pascual, Sergio

    2010-01-01

    Water resources and water footprint of the production and consumption in Madrid region were estimated, considering blue water (water resources), green water (soil moisture), grey water (polluted water) and virtual water (water trade in products imported and exported in the region). Water resources in Madrid relay mainly in surface waters and rainfall, so the periodic occurrence of meteorological droughts implies the scarcity of water supply. The main users of blue water are households, munici...

  10. Getting brand commitment through internet and mobile sports marketing: an insight on Real Madrid football team

    OpenAIRE

    Baena Graciá, Verónica

    2014-01-01

    This chapter provides a better understanding of the impact that the Internet and mobile sports marketing are having on a business's ability to achieve customer engagement. To achieve this goal, the case of Real Madrid football team is analyzed, as it is calculated to have over 200 million supporters worldwide. Information about Real Madrid was gathered from September 2012 to March 2013 by repeatedly browsing the team's Website, Facebook, Twitter, Instagram, and apps. Data from interviews of R...

  11. Intensity Based Seismic Hazard Map of Republic of Macedonia

    Science.gov (United States)

    Dojcinovski, Dragi; Dimiskovska, Biserka; Stojmanovska, Marta

    2016-04-01

    The territory of the Republic of Macedonia and the border terrains are among the most seismically active parts of the Balkan Peninsula belonging to the Mediterranean-Trans-Asian seismic belt. The seismological data on the R. Macedonia from the past 16 centuries point to occurrence of very strong catastrophic earthquakes. The hypocenters of the occurred earthquakes are located above the Mohorovicic discontinuity, most frequently, at a depth of 10-20 km. Accurate short -term prognosis of earthquake occurrence, i.e., simultaneous prognosis of time, place and intensity of their occurrence is still not possible. The present methods of seismic zoning have advanced to such an extent that it is with a great probability that they enable efficient protection against earthquake effects. The seismic hazard maps of the Republic of Macedonia are the result of analysis and synthesis of data from seismological, seismotectonic and other corresponding investigations necessary for definition of the expected level of seismic hazard for certain time periods. These should be amended, from time to time, with new data and scientific knowledge. The elaboration of this map does not completely solve all issues related to earthquakes, but it provides basic empirical data necessary for updating the existing regulations for construction of engineering structures in seismically active areas regulated by legal regulations and technical norms whose constituent part is the seismic hazard map. The map has been elaborated based on complex seismological and geophysical investigations of the considered area and synthesis of the results from these investigations. There were two phases of elaboration of the map. In the first phase, the map of focal zones characterized by maximum magnitudes of possible earthquakes has been elaborated. In the second phase, the intensities of expected earthquakes have been computed according to the MCS scale. The map is prognostic, i.e., it provides assessment of the

  12. Seismic imaging of sandbox experiments – laboratory hardware setup and first reflection seismic sections

    Directory of Open Access Journals (Sweden)

    C. M. Krawczyk

    2013-02-01

    Full Text Available With the study and technical development introduced here, we combine analogue sandbox simulation techniques with seismic physical modelling of sandbox models. For that purpose, we designed and developed a new mini-seismic facility for laboratory use, comprising a seismic tank, a PC-driven control unit, a positioning system, and piezoelectric transducers used here for the first time in an array mode. To assess the possibilities and limits of seismic imaging of small-scale structures in sandbox models, different geometry setups were tested in the first 2-D experiments that also tested the proper functioning of the device and studied the seismo-elastic properties of the granular media used. Simple two-layer models of different materials and layer thicknesses as well as a more complex model comprising channels and shear zones were tested using different acquisition geometries and signal properties. We suggest using well sorted and well rounded grains with little surface roughness (glass beads. Source receiver-offsets less than 14 cm for imaging structures as small as 2.0–1.5 mm size have proven feasible. This is the best compromise between wide beam and high energy output, and is applicable with a consistent waveform. Resolution of the interfaces of layers of granular materials depends on the interface preparation rather than on the material itself. Flat grading of interfaces and powder coverage yields the clearest interface reflections. Finally, sandbox seismic sections provide images of high quality showing constant thickness layers as well as predefined channel structures and indications of the fault traces from shear zones. Since these were artificially introduced in our test models, they can be regarded as zones of disturbance rather than tectonic shear zones characterized by decompaction. The multiple-offset surveying introduced here, improves the quality with respect to S / N ratio and source signature even more; the maximum depth

  13. Correlation of Crustal Structures and Seismicity Patterns in Northern Appalachians

    Science.gov (United States)

    Yang, X.; Gao, H.

    2017-12-01

    The earthquake distributions in northern Appalachians are bounded by major geologically-defined terrane boundaries. There is a distinct seismic gap within Taconic Belt between the Western Quebec Seismic Zone (WQSZ) to the west and the seismically active Ganderia terrane to the east. It is not clear, however, what crustal structures control the characteristics of earthquake clustering in this region. Here we present a newly constructed crustal shear velocity model for the northern Appalachians using Rayleigh wave data extracted from ambient noises. Our tomographic model reveals strongly heterogeneous seismic structures in the crust. We observe multiple NW-dipping patches of high-velocity anomalies in the upper crust beneath the southeastern WQSZ. The upper crust shear velocities in the Ganderia and Avalonia region are generally lower than those beneath the WQSZ. The middle crust has relatively lower velocities in the study area. The earthquakes in the study area are constrained within the upper crust. Most of the earthquake hypocenters within the WQSZ are concentrated along the NW-dipping boundaries separating the high-velocity anomalies. In contrast, most of the earthquake hypocenters in the Ganderia and Avalonia region are diffusely distributed without clear vertical lineaments. The orientations of maximum compressive stresses change from W-E in the Ganderia and Avalonia region to SW-NE in the WQSZ. The contrasts in seismicity, velocity, and stress field across the Taconic Belt indicate that the Taconic Belt terrane may act as a seismically inactive buffer zone in northern Appalachians.

  14. The Texcoco Seismic Array: Analysis of the Seismic Movement in the Deep Sediments of Mexico Basin.

    Science.gov (United States)

    Flores-Estrella, H.; Cardenas-Soto, M.; Lomnitz, C.

    2007-05-01

    The seismic movement in the Lake Zone of the Mexico Basin is characterized by long durations and late energy arrivals; many efforts have been made to find the origin of these late waves. In 1997 the Texcoco Seismic Array (TXC) was installed in the former Lake of Texcoco, in the northeastern part of Mexico Basin. It is a natural reserve formed by the same lacustrine clays of the Lake Zone in Mexico City, however we consider TXC as a virgin site as there are no buildings near, and there is almost no human activity. We analyzed 7 earthquakes recorded at TXC in two instrumental arrays, to identify late energy arrivals near the fundamental period and we also analyzed these pulses with F-K method to estimate the phase velocity and its origin.

  15. The Seismic Analyzer: Interpreting and Illustrating 2D Seismic Data

    OpenAIRE

    Patel, Daniel; Giertsen, Christopher; Thurmond, John; Gjelberg, John; Gröller, Eduard

    2008-01-01

    We present a toolbox for quickly interpreting and illustrating 2D slices of seismic volumetric reflection data. Searching for oil and gas involves creating a structural overview of seismic reflection data to identify hydrocarbon reservoirs. We improve the search of seismic structures by precalculating the horizon structures of the seismic data prior to interpretation. We improve the annotation of seismic structures by applying novel illustrative rendering algorithms tailored to seism...

  16. GuMNet - Guadarrama Monitoring Network initiative (Madrid,Spain)

    Science.gov (United States)

    Santolaria-Canales, Edmundo

    2017-04-01

    The Guadarrama Monitoring Network initiative (GuMNet) is an observational infrastructure focused on monitoring the state of the atmosphere, surface and subsurface in the Sierra de Guadarrama, 50 km NW of the city of Madrid. The network is composed of 10 automatic real time weather stations ranging from low altitude (ca. 900 m.a.s.l) to high mountain areas (ca. 2400 m.a.s.l). The GuMNet infrastructure consists in 10 real time automatic weather stations with instrumentation for observing the state of the atmosphere, surface and the subsurface at the Sierra de Guadarrama, just 50 km north-northwest of the city of Madrid. GuMNet lays the foundations of a research network on weather, soil thermodynamics, boundary layer physics, climate and ecosystem oriented impacts, air pollutions, etc. in the Sierra de Guadarrama. GuMNet represents a first step to provide a unique observational network in an environment of high protection to be used as a laboratory serving a wide range of scientific and educational interests. High altitude sites are focused on periglacial areas and lower altitude sites have emphasis on pastures. One of the low altitude sites is equipped with a 10 m high anemometric tower with a 3D sonic anemometer at the top jointly with a CO2/H2O analyzer that will allow sampling of wind profiles and H2O and CO2 eddy covariance fluxes, important for soil respiration and CO2 and water vapor exchange. A portable station has also a 3D sonic anemometer with CO2/H2O analyzer, this 4 meters-high portable tower is designed for comparison with other soil terrain fluxes. The network is connected via general packet radio service (GPRS) to the central lab in the Campus of Excellence of Moncloa and a management software has been developed to handle the operation of the infrastructure. The deployment of instrumentation and connection of sites to the network was finished in 2016. GuMNet is currently in the process of becoming operational. Conceptually, GuMNet intends to convert a

  17. Spatial pattern recognition of seismic events in South West Colombia

    Science.gov (United States)

    Benítez, Hernán D.; Flórez, Juan F.; Duque, Diana P.; Benavides, Alberto; Lucía Baquero, Olga; Quintero, Jiber

    2013-09-01

    Recognition of seismogenic zones in geographical regions supports seismic hazard studies. This recognition is usually based on visual, qualitative and subjective analysis of data. Spatial pattern recognition provides a well founded means to obtain relevant information from large amounts of data. The purpose of this work is to identify and classify spatial patterns in instrumental data of the South West Colombian seismic database. In this research, clustering tendency analysis validates whether seismic database possesses a clustering structure. A non-supervised fuzzy clustering algorithm creates groups of seismic events. Given the sensitivity of fuzzy clustering algorithms to centroid initial positions, we proposed a methodology to initialize centroids that generates stable partitions with respect to centroid initialization. As a result of this work, a public software tool provides the user with the routines developed for clustering methodology. The analysis of the seismogenic zones obtained reveals meaningful spatial patterns in South-West Colombia. The clustering analysis provides a quantitative location and dispersion of seismogenic zones that facilitates seismological interpretations of seismic activities in South West Colombia.

  18. Application of probabilistic seismic hazard models with special calculation for the waste storage sites in Egypt

    International Nuclear Information System (INIS)

    Othman, A.A.; El-Hemamy, S.T.

    2000-01-01

    Probabilistic strong motion maps of Egypt are derived by applying Gumbel models and likelihood method to 8 earthquake source zones in Egypt and adjacent regions. Peak horizontal acceleration is mapped. Seismic data are collected from Helwan Catalog (1900-1997), regional catalog of earthquakes from the International Seismological Center (ISC,1910-1993) and earthquake data reports of US Department of International Geological Survey (USCGS, 1900-1994). Iso-seismic maps are also available for some events, which occurred in Egypt. Some earthquake source zones are well defined on the basis of both tectonics and average seismicity rates, but a lack of understanding of the near field effects of the large earthquakes prohibits accurate estimates of ground motion in their vicinity. Some source zones have no large-scale crustal features or zones of weakness that can explain the seismicity and must, therefore, be defined simply as concentrations of seismic activity with no geological or geophysical controls on the boundaries. Other source zones lack information on low-magnitude seismicity that would be representative of longer periods of time. Comparisons of the new probabilistic ground motion estimates in Egypt with equivalent estimates made in 1990 have been done. The new ground motion estimates are used to produce a new peak ground acceleration map to replace the 1990 peak acceleration zoning maps in the Building code of Egypt. (author)

  19. Lithospheric strucutre and relationship to seismicity beneath the Southeastern US using reciever functions

    Science.gov (United States)

    Cunningham, E.; Lekic, V.

    2017-12-01

    Despite being on a passive margin for millions of years, the Southeastern United States (SEUS) contains numerous seismogenic zones with the ability to produce damaging earthquakes. However, mechanisms controlling these intraplate earthquakes are poorly understood. Recently, Biryol et al. 2016 use P-wave tomography suggest that upper mantle structures beneath the SEUS correlate with areas of seismicity and seismic quiescence. Specifically, thick and fast velocity lithosphere beneath North Carolina is stable and indicative of areas of low seismicity. In contrast, thin and slow velocity lithosphere is weak, and the transition between the strong and weak lithosphere may be correlated with seismogenic zones found in the SEUS. (eg. Eastern Tennessee seismic zone and the Central Virginia seismic zone) Therefore, I systematically map the heterogeneity of the mantle lithosphere using converted seismic waves and quantify the spatial correlation between seismicity and lithospheric structure. The extensive network of seismometers that makes up the Earthscope USArray combined with the numerous seismic deployments in the Southeastern United States allows for unprecedented opportunity to map changes in lithospheric structure across seismogenic zones and seismic quiescent regions. To do so, I will use both P-to-s and S-to-p receiver functions (RFS). Since RFs are sensitive to seismic wavespeeds and density discontinuities with depth, they particularly useful for studying lithospheric structure. Ps receiver functions contain high frequency information allowing for high resolution, but can become contaminated by large sediment signals; therefore, I removed sediment multiples and correct for time delays of later phases using the method of Yu et. al 2015 which will allow us to see later arriving phases associated with lithospheric discontinuities. S-to-p receiver functions are not contaminated by shallow layers, making them ideal to study deep lithospheric structures but they can

  20. ANZA Seismic Network- From Monitoring to Science

    Science.gov (United States)

    Vernon, F.; Eakin, J.; Martynov, V.; Newman, R.; Offield, G.; Hindley, A.; Astiz, L.

    2007-05-01

    The ANZA Seismic Network (http:eqinfo.ucsd.edu) utilizes broadband and strong motion sensors with 24-bit dataloggers combined with real-time telemetry to monitor local and regional seismicity in southernmost California. The ANZA network provides real-time data to the IRIS DMC, California Integrated Seismic Network (CISN), other regional networks, and the Advanced National Seismic System (ANSS), in addition to providing near real-time information and monitoring to the greater San Diego community. Twelve high dynamic range broadband and strong motion sensors adjacent to the San Jacinto Fault zone contribute data for earthquake source studies and continue the monitoring of the seismic activity of the San Jacinto fault initiated 24 years ago. Five additional stations are located in the San Diego region with one more station on San Clemente Island. The ANZA network uses the advance wireless networking capabilities of the NSF High Performance Wireless Research and Education Network (http:hpwren.ucsd.edu) to provide the communication infrastructure for the real-time telemetry of Anza seismic stations. The ANZA network uses the Antelope data acquisition software. The combination of high quality hardware, communications, and software allow for an annual network uptime in excess of 99.5% with a median annual station real-time data return rate of 99.3%. Approximately 90,000 events, dominantly local sources but including regional and teleseismic events, comprise the ANZA network waveform database. All waveform data and event data are managed using the Datascope relational database. The ANZA network data has been used in a variety of scientific research including detailed structure of the San Jacinto Fault Zone, earthquake source physics, spatial and temporal studies of aftershocks, array studies of teleseismic body waves, and array studies on the source of microseisms. To augment the location, detection, and high frequency observations of the seismic source spectrum from local

  1. Ancestry Analysis in the 11-M Madrid Bomb Attack Investigation

    Science.gov (United States)

    Phillips, Christopher; Prieto, Lourdes; Fondevila, Manuel; Salas, Antonio; Gómez-Tato, Antonio; Álvarez-Dios, José; Alonso, Antonio; Blanco-Verea, Alejandro; Brión, María; Montesino, Marta; Carracedo, Ángel; Lareu, María Victoria

    2009-01-01

    The 11-M Madrid commuter train bombings of 2004 constituted the second biggest terrorist attack to occur in Europe after Lockerbie, while the subsequent investigation became the most complex and wide-ranging forensic case in Spain. Standard short tandem repeat (STR) profiling of 600 exhibits left certain key incriminatory samples unmatched to any of the apprehended suspects. A judicial order to perform analyses of unmatched samples to differentiate European and North African ancestry became a critical part of the investigation and was instigated to help refine the search for further suspects. Although mitochondrial DNA (mtDNA) and Y-chromosome markers routinely demonstrate informative geographic differentiation, the populations compared in this analysis were known to show a proportion of shared mtDNA and Y haplotypes as a result of recent gene-flow across the western Mediterranean, while any two loci can be unrepresentative of the ancestry of an individual as a whole. We based our principal analysis on a validated 34plex autosomal ancestry-informative-marker single nucleotide polymorphism (AIM-SNP) assay to make an assignment of ancestry for DNA from seven unmatched case samples including a handprint from a bag containing undetonated explosives together with personal items recovered from various locations in Madrid associated with the suspects. To assess marker informativeness before genotyping, we predicted the probable classification success for the 34plex assay with standard error estimators for a naïve Bayesian classifier using Moroccan and Spanish training sets (each n = 48). Once misclassification error was found to be sufficiently low, genotyping yielded seven near-complete profiles (33 of 34 AIM-SNPs) that in four cases gave probabilities providing a clear assignment of ancestry. One of the suspects predicted to be North African by AIM-SNP analysis of DNA from a toothbrush was identified late in the investigation as Algerian in origin. The results

  2. Romanian earthquakes analysis using BURAR seismic array

    International Nuclear Information System (INIS)

    Borleanu, Felix; Rogozea, Maria; Nica, Daniela; Popescu, Emilia; Popa, Mihaela; Radulian, Mircea

    2008-01-01

    Bucovina seismic array (BURAR) is a medium-aperture array, installed in 2002 in the northern part of Romania (47.61480 N latitude, 25.21680 E longitude, 1150 m altitude), as a result of the cooperation between Air Force Technical Applications Center, USA and National Institute for Earth Physics, Romania. The array consists of ten elements, located in boreholes and distributed over a 5 x 5 km 2 area; nine with short-period vertical sensors and one with a broadband three-component sensor. Since the new station has been operating the earthquake survey of Romania's territory has been significantly improved. Data recorded by BURAR during 01.01.2005 - 12.31.2005 time interval are first processed and analyzed, in order to establish the array detection capability of the local earthquakes, occurred in different Romanian seismic zones. Subsequently a spectral ratios technique was applied in order to determine the calibration relationships for magnitude, using only the information gathered by BURAR station. The spectral ratios are computed relatively to a reference event, considered as representative for each seismic zone. This method has the advantage to eliminate the path effects. The new calibration procedure is tested for the case of Vrancea intermediate-depth earthquakes and proved to be very efficient in constraining the size of these earthquakes. (authors)

  3. First level seismic microzonation map of Chennai city – a GIS approach

    Directory of Open Access Journals (Sweden)

    G. P. Ganapathy

    2011-02-01

    Full Text Available Chennai city is the fourth largest metropolis in India, is the focus of economic, social and cultural development and it is the capital of the State of Tamil Nadu. The city has a multi-dimensional growth in development of its infrastructures and population. The area of Chennai has experienced moderate earthquakes in the historical past. Also the Bureau of Indian Standard upgraded the seismic status of Chennai from Low Seismic Hazard (Zone II to Moderate Seismic Hazard (Zone III–(BIS: 1893 (2001. In this connection, a first level seismic microzonation map of Chennai city has been produced with a GIS platform using the themes, viz, Peak Ground Acceleration (PGA, Shear wave velocity at 3 m, Geology, Ground water fluctuation and bed rock depth. The near potential seismic sources were identified from the remote-sensing study and seismo-tectonic details from published literatures. The peak ground acceleration for these seismic sources were estimated based on the attenuation relationship and the maximum PGA for Chennai is 0.176 g. The groundwater fluctuation of the city varies from 0–4 m below ground level. The depth to bedrock configuration shows trough and ridges in the bedrock topography all over the city. The seismic microzonation analysis involved grid datasets (the discrete datasets from different themes were converted to grids to compute the final seismic hazard grid through integration and weightage analysis of the source themes. The Chennai city has been classified into three broad zones, viz, High, Moderate and Low Seismic Hazard. The High seismic Hazard concentrated in a few places in the western central part of the city. The moderate hazard areas are oriented in NW-SE direction in the Western part. The southern and eastern part will have low seismic hazard. The result of the study may be used as first-hand information in selecting the appropriate earthquake resistant features in designing the forthcoming new buildings against seismic

  4. CONCIDERATION OF FOUNDATION AND SEISMIC CONDITIONS OF AREA IN ANALYSIS OF SEISMIC RESISTANCE OF REACTOR COMPARTMENT

    Directory of Open Access Journals (Sweden)

    SEDIN V. L.

    2015-11-01

    Full Text Available Problem statement. Providing of safe exploitation of nuclear power plants, as well as a safety of staff and environment is a very important problem. A distinct feature of this problem is a necessity to provide not only a strength of structures, but also a safe functioning of all systems that control nuclear process. In particular, the influence of earthquake should be considered on constructions of buildings and structures of nuclear and thermal power plant, taking into account soil-structure interaction. According to IAEA’s SSD-9 recommendations, a risk of vibration of soil should be analyzed for each NPP connected with earthquakes soil that means researches, including general, detailed and microseismic zoning of the area works. One of the distinctive features of the considered problem is an evaluation of the seismicity of area and getting the response spectrum on the free surface. Purpose. Determination of seismic resistance of buildings of high category of safety with the example of the reactor compartment of Zaporoghskaya NPP including the soil structure interaction. Conclusion The seismicity assessment of the area and obtaining of response specters on free surface was made during research and analysis of seismic resistance of buildings of high category of safety including the effects of foundation and structures. The method of modeling of the equivalent dynamic characteristics of the base was considered during the research in seismic impacts.

  5. Worldwide Assessment of the Status of Seismic Zonation, Fourth International Forum on Seismic Zonation, Proceedings

    Science.gov (United States)

    Hays, W.W.

    1994-01-01

    We are pleased to provide you with information developed for the Fourth International Forum on Seismic Zonation which will be convened in two locations year in conjunction two major international meetings. The objectives are: 1) to assess the status of seismic zonation in every country of the world, 2) to evaluate the reasons for advances and new initiatives, and 3) to foster continued cooperation. Seismic zonation is the process that leads to risk reduction and sustainability of new development. It is based on the division of a geographic region into smaller areas or zones on the basis of an integrated assessment of the hazard, built, and policy environments of the region. Seismic zonation depends on hazard mapping performed on national/regional, subregional, and urban (i.e., microzonation) scales depending on the particular application. We gratefully acknowledge the written communications of many professionals who responded to our request for information. Also, we acknowledge the use of information contained in five valuable reports (see directories in the Appendices for information on where to obtain copies of the reports): 1. United Nations, 1990, Cooperative Project for Seismic Risk Reduction in the Mediterranean Region (SEISMED), proceedings, Office of the United Nations Disaster Relief Coordinator, Geneva, Switzerland, 3 vols. (Franco Maranzana -

  6. Design experience on seismically isolated buildings

    International Nuclear Information System (INIS)

    Giuliani, G.C.

    1989-01-01

    This paper describes the practical problems associated with the structural design of a group of seismically isolated buildings now under construction in Ancona, Italy. These structures are the first seismically isolated buildings in Italy. Taking into account previous earthquakes, the structural design of these new buildings was performed according to an acceleration spectrum which was different from its Zone 2 seismic code and which provided protection for stronger ground motions. To minimize the cost of the structure, the buildings used ribbed plate decks, thus reducing the amount of material and the mass of the structures to be isolated. The design requirements, dynamic analysis performed, structural design, and practical engineering employed are reported in this paper. A comparison between the costs of a conventionally designed and a base-isolated structure is also reported. The tests undertaken for certifying the mechanical properties of the isolators for both static and dynamic loads are also described, as is the full-scale dynamic test which is scheduled for next year (1990) for one of the completed buildings. Lessons learned in this design effort are potentially applicable to seismic base isolation for nuclear power plants

  7. Extreme loads seismic testing of conduit systems

    International Nuclear Information System (INIS)

    Howard, G.E.; Ibanez, P.; Harrison, S.; Shi, Z.T.

    1991-01-01

    Rigid steel conduit (thin-wall tubes with threaded connections) containing electrical cabling are a common feature in nuclear power plants. Conduit systems are in many cases classified in U.S.A. practice as Seismic Category I structures. this paper summarizes results and others aspects of a dynamic test program conducted to investigate conduit systems seismic performance under three-axis excitation for designs representative at a nuclear power plant sited near Ft. Worth, Texas (a moderate seismic zone), with a Safe Shutdown Earthquake (SSE) of 0.12 g. Test specimens where subjected to postulated seismic events, including excitation well in excess of Safe Shutdown Earthquake events typical for U.S.A. nuclear power stations. A total of 18 conduit systems of 9-meter nominal lengths were shake table mounted and subjected to a variety of tests. None of the specimens suffered loss of load capacity when subjected to a site-enveloping Safe Shutdown Earthquake (SSE). Clamp/attachment hardware failures only began to occur when earthquake input motion was scaled upward to minimum values of 2.3-4.6 times site enveloping SSE response spectra. Tensile and/or shear failure of clamp attachment bolts or studs was the failure mode in all case in which failure was induced. (author)

  8. Probabilistic Seismic Hazard Assessment for Northeast India Region

    Science.gov (United States)

    Das, Ranjit; Sharma, M. L.; Wason, H. R.

    2016-08-01

    Northeast India bounded by latitudes 20°-30°N and longitudes 87°-98°E is one of the most seismically active areas in the world. This region has experienced several moderate-to-large-sized earthquakes, including the 12 June, 1897 Shillong earthquake ( M w 8.1) and the 15 August, 1950 Assam earthquake ( M w 8.7) which caused loss of human lives and significant damages to buildings highlighting the importance of seismic hazard assessment for the region. Probabilistic seismic hazard assessment of the region has been carried out using a unified moment magnitude catalog prepared by an improved General Orthogonal Regression methodology (Geophys J Int, 190:1091-1096, 2012; Probabilistic seismic hazard assessment of Northeast India region, Ph.D. Thesis, Department of Earthquake Engineering, IIT Roorkee, Roorkee, 2013) with events compiled from various databases (ISC, NEIC,GCMT, IMD) and other available catalogs. The study area has been subdivided into nine seismogenic source zones to account for local variation in tectonics and seismicity characteristics. The seismicity parameters are estimated for each of these source zones, which are input variables into seismic hazard estimation of a region. The seismic hazard analysis of the study region has been performed by dividing the area into grids of size 0.1° × 0.1°. Peak ground acceleration (PGA) and spectral acceleration ( S a) values (for periods of 0.2 and 1 s) have been evaluated at bedrock level corresponding to probability of exceedance (PE) of 50, 20, 10, 2 and 0.5 % in 50 years. These exceedance values correspond to return periods of 100, 225, 475, 2475, and 10,000 years, respectively. The seismic hazard maps have been prepared at the bedrock level, and it is observed that the seismic hazard estimates show a significant local variation in contrast to the uniform hazard value suggested by the Indian standard seismic code [Indian standard, criteria for earthquake-resistant design of structures, fifth edition, Part

  9. Escenario para una Corte real: Madrid en tiempos de Enrique IV

    Directory of Open Access Journals (Sweden)

    María del Pilar RÁBADE OBRADÓ

    2009-05-01

    Full Text Available Este trabajo pretende estudiar la itinerancia cortesana durante el reinado de Enrique IV de Castilla (1454-1474, en relación con el caso concreto de Madrid. El estudio se va a realizar a través del análisis de la crónica del reinado redactada por Diego Enríquez del Castillo. Durante el reinado de Enrique IV, Madrid fue la ciudad que se convirtió con más frecuencia en residencia de la Corte. Lo fue porque Madrid contaba con alicientes como su estratégica ubicación geográfica, su potente alcázar y la proximidad con el cazadero de El Pardo. Madrid albergó a la Corte en momentos de calma y sosiego y en otros convulsos y difíciles. Además, Madrid fue testigo de acontecimientos muy destacados de la vida del rey: el nacimiento de su hija Juana, e incluso su muerte.Ce travail essaie d'étudier l'itinérance de la cour pendant le règne d'Henri IV de Castille (1454-1474, en relation avec le cas concret de Madrid. L'étude partira de l'analyse de la chronique du règne rédigée par Diego Enríquez del Castillo. Sous Henri IV, Madrid a été la ville qui s'est le plus fréquemment convertie en résidence de la cour. En effet, Madrid disposait des attraits suivants : sa situation géographique stratégique, son puissant alcazar et la proximité du manoir de chasse d’El Pardo. Madrid a hébergé la cour dans des moments de calme comme dans des périodes agitées. De plus, Madrid a été témoin d'événements importants de la vie du roi : la naissance de sa fille Juana, et même sa mort.

  10. Reprocessing seismic data: better results below diabase sills

    Energy Technology Data Exchange (ETDEWEB)

    Makler, Marisa [Halliburton Servicos Ltda., Rio de Janeiro, RJ (Brazil); Pellizzon, Marcela

    2008-07-01

    The effect of the diabase sills in the seismic data processing has been studied in the last twenty years. These rocks strongly influence the exploratory activities in a basin, because the diabase disturbs the sign and generates multiple and spherical divergence, increasing the exploratory risk in these areas. In the present work a method of 2D seismic reprocessing will be presented using Prestack Kirchhoff Time Migration in an older seismic data of Solimoes basin. The objective of this paper is to show the high results on the reprocessing seismic data below the diabase sills. The 2D lines processed give relevant improvement of the quality of signal, showing better the faults zones and preserving the geological structures than the older data. (author)

  11. Seismic characterization of CO{sub 2} in coals

    Energy Technology Data Exchange (ETDEWEB)

    McCrank, J.; Lawton, D.C. [Calgary Univ., AB (Canada). Dept. of Geoscience, Consortium for Research in Elastic Wave Exploration Seismology

    2008-07-01

    The Mynheer coal seam was targeted for an enhanced coalbed methane (CBM) experiment. During initial testing of the reservoir permeability, 180 tonnes of carbon dioxide (CO{sub 2}) was injected into the seam. The objective of the study was to characterize the coal zones and to determine if the small volume of CO{sub 2} in the thinly bedded and seismically tuned reservoir can be detected in the 3D surface seismic data. The multi-well pilot project took place in the Pembina Field of west-central Alberta. The Ardley coals were tested for CO{sub 2} injection, enhanced CBM production, and CO{sub 2} sequestration. The seismic survey captured the condition of the reservoir after formation permeability tests. It was concluded that the anomalies seen in the seismic data can be attributed to changes in the physical properties of the coal due to CO{sub 2} adsorption. 2 refs., 5 figs.

  12. GUI program to compute probabilistic seismic hazard analysis

    International Nuclear Information System (INIS)

    Shin, Jin Soo; Chi, H. C.; Cho, J. C.; Park, J. H.; Kim, K. G.; Im, I. S.

    2005-12-01

    The first stage of development of program to compute probabilistic seismic hazard is completed based on Graphic User Interface (GUI). The main program consists of three part - the data input processes, probabilistic seismic hazard analysis and result output processes. The first part has developed and others are developing now in this term. The probabilistic seismic hazard analysis needs various input data which represent attenuation formulae, seismic zoning map, and earthquake event catalog. The input procedure of previous programs based on text interface take a much time to prepare the data. The data cannot be checked directly on screen to prevent input erroneously in existing methods. The new program simplifies the input process and enable to check the data graphically in order to minimize the artificial error within the limits of the possibility

  13. GUI program to compute probabilistic seismic hazard analysis

    International Nuclear Information System (INIS)

    Shin, Jin Soo; Chi, H. C.; Cho, J. C.; Park, J. H.; Kim, K. G.; Im, I. S.

    2006-12-01

    The development of program to compute probabilistic seismic hazard is completed based on Graphic User Interface(GUI). The main program consists of three part - the data input processes, probabilistic seismic hazard analysis and result output processes. The probabilistic seismic hazard analysis needs various input data which represent attenuation formulae, seismic zoning map, and earthquake event catalog. The input procedure of previous programs based on text interface take a much time to prepare the data. The data cannot be checked directly on screen to prevent input erroneously in existing methods. The new program simplifies the input process and enable to check the data graphically in order to minimize the artificial error within limits of the possibility

  14. The Use Of Seismic Velocities For The Prediction Of Abnormal ...

    African Journals Online (AJOL)

    Ninety (90) velocity control points derived from seismic data processing were examined and analyzed to evaluate abnormal pressure zones in parts of onshore western Niger - Delta. Compaction trend graphs and a map showing the distribution of top of overpressure were produced. The graphs show that compaction ...

  15. Seismic hazard assessment in the Ibero-Maghreb region

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, M.J.; Garcia fernandez, M. [Consejo Superior de Investigaciones Cientifcas, Barcelona (Spain). Inst. of Earth Sciences; GSAHP Ibero-Maghreb Working Group

    1999-12-01

    The paper illustrates the contribution of the Ibero-Maghreb region to the global GSHAP (Global Seismic Hazard Assessment Program) map: for the first time, a map of regional hazard source zones is presented and agreement on a common procedure for hazard computation in the region has been achieved.

  16. Data base and seismicity studies for Fagaras, Romania crustal earthquakes

    International Nuclear Information System (INIS)

    Moldovan, I.-A.; Enescu, B. D.; Pantea, A.; Constantin, A.; Bazacliu, O.; Malita, Z.; Moldoveanu, T.

    2002-01-01

    Besides the major impact of the Vrancea seismic region, one of the most important intermediate earthquake sources of Europe, the Romanian crustal earthquake sources, from Fagaras, Banat, Crisana, Bucovina or Dobrogea regions, have to be taken into consideration for seismicity studies or seismic hazard assessment. To determine the characteristics of the seismicity for Fagaras seismogenic region, a revised and updated catalogue of the Romanian earthquakes, recently compiled by Oncescu et al. (1999) is used. The catalogue contains 471 tectonic earthquakes and 338 induced earthquakes and is homogenous starting with 1471 for I>VIII and for I>VII starting with 1801. The catalogue is complete for magnitudes larger than 3 starting with 1982. In the studied zone only normal earthquakes occur, related to intracrustal fractures situated from 5 to 30 km depth. Most of them are of low energy, but once in a century a large destructive event occurs with epicentral intensity larger than VIII. The maximum expected magnitude is M GR = 6.5 and the epicenter distribution outlines significant clustering in the zones and on the lines mentioned in the tectonic studies. Taking into account the date of the last major earthquake (1916) and the return periods of severe damaging shocks of over 85 years it is to be expected very soon a large shock in the area. That's why a seismicity and hazard study for this zone is necessary. In the paper there are studied the b parameter variation (the mean value is 0.69), the activity value, the return periods, and seismicity maps and different histograms are plotted. At the same time there are excluded from the catalogue the explosions due to Campulung quarry. Because the catalogue contains the aftershocks for the 1916 earthquake for the seismicity studies we have excluded these shocks. (authors)

  17. A New Seismic Hazard Model for Mainland China

    Science.gov (United States)

    Rong, Y.; Xu, X.; Chen, G.; Cheng, J.; Magistrale, H.; Shen, Z. K.

    2017-12-01

    We are developing a new seismic hazard model for Mainland China by integrating historical earthquake catalogs, geological faults, geodetic GPS data, and geology maps. To build the model, we construct an Mw-based homogeneous historical earthquake catalog spanning from 780 B.C. to present, create fault models from active fault data, and derive a strain rate model based on the most complete GPS measurements and a new strain derivation algorithm. We divide China and the surrounding regions into about 20 large seismic source zones. For each zone, a tapered Gutenberg-Richter (TGR) magnitude-frequency distribution is used to model the seismic activity rates. The a- and b-values of the TGR distribution are calculated using observed earthquake data, while the corner magnitude is constrained independently using the seismic moment rate inferred from the geodetically-based strain rate model. Small and medium sized earthquakes are distributed within the source zones following the location and magnitude patterns of historical earthquakes. Some of the larger earthquakes are distributed onto active faults, based on their geological characteristics such as slip rate, fault length, down-dip width, and various paleoseismic data. The remaining larger earthquakes are then placed into the background. A new set of magnitude-rupture scaling relationships is developed based on earthquake data from China and vicinity. We evaluate and select appropriate ground motion prediction equations by comparing them with observed ground motion data and performing residual analysis. To implement the modeling workflow, we develop a tool that builds upon the functionalities of GEM's Hazard Modeler's Toolkit. The GEM OpenQuake software is used to calculate seismic hazard at various ground motion periods and various return periods. To account for site amplification, we construct a site condition map based on geology. The resulting new seismic hazard maps can be used for seismic risk analysis and management.

  18. Seismic analysis for translational failure of landfills with retaining walls.

    Science.gov (United States)

    Feng, Shi-Jin; Gao, Li-Ya

    2010-11-01

    In the seismic impact zone, seismic force can be a major triggering mechanism for translational failures of landfills. The scope of this paper is to develop a three-part wedge method for seismic analysis of translational failures of landfills with retaining walls. The approximate solution of the factor of safety can be calculated. Unlike previous conventional limit equilibrium methods, the new method is capable of revealing the effects of both the solid waste shear strength and the retaining wall on the translational failures of landfills during earthquake. Parameter studies of the developed method show that the factor of safety decreases with the increase of the seismic coefficient, while it increases quickly with the increase of the minimum friction angle beneath waste mass for various horizontal seismic coefficients. Increasing the minimum friction angle beneath the waste mass appears to be more effective than any other parameters for increasing the factor of safety under the considered condition. Thus, selecting liner materials with higher friction angle will considerably reduce the potential for translational failures of landfills during earthquake. The factor of safety gradually increases with the increase of the height of retaining wall for various horizontal seismic coefficients. A higher retaining wall is beneficial to the seismic stability of the landfill. Simply ignoring the retaining wall will lead to serious underestimation of the factor of safety. Besides, the approximate solution of the yield acceleration coefficient of the landfill is also presented based on the calculated method. Copyright © 2010 Elsevier Ltd. All rights reserved.

  19. Seismic refraction survey of the ANS preferred site

    Energy Technology Data Exchange (ETDEWEB)

    Davis, R.K. (Automated Sciences Group, Inc., Oak Ridge, TN (United States)); Hopkins, R.A. (Marrich, Inc., Knoxville, TN (United States)); Doll, W.E. (Oak Ridge National Lab., TN (United States))

    1992-02-01

    Between September 19, 1991 and October 8, 1991 personnel from Martin Marietta Energy Systems, Inc. (Energy Systems), Automated Sciences Group, Inc., and Marrich, Inc. performed a seismic refraction survey at the Advanced Neutron Source (ANS) preferred site. The purpose of this survey was to provide estimates of top-of-rock topography, based on seismic velocities, and to delineate variations in rock and soil velocities. Forty-four seismic refraction spreads were shot to determine top-of-rock depths at 42 locations. Nine of the seismic spreads were shot with long offsets to provide 216 top-of-rock depths for 4 seismic refraction profiles. The refraction spread locations were based on the grid for the ANS Phase I drilling program. Interpretation of the seismic refraction data supports the assumption that the top-of-rock surface generally follows the local topography. The shallow top-of-rock interface interpreted from the seismic refraction data is also supported by limited drill information at the site. Some zones of anomalous data are present that could be the result of locally variable weathering, a localized variation in shale content, or depth to top-of-rock greater than the site norm.

  20. Seismic Creep, USA Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Seismic creep is the constant or periodic movement on a fault as contrasted with the sudden rupture associated with an earthquake. It is a usually slow deformation...

  1. BUILDING 341 Seismic Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Halle, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-06-15

    The Seismic Evaluation of Building 341 located at Lawrence Livermore National Laboratory in Livermore, California has been completed. The subject building consists of a main building, Increment 1, and two smaller additions; Increments 2 and 3.

  2. Seismic data acquisition systems

    International Nuclear Information System (INIS)

    Kolvankar, V.G.; Nadre, V.N.; Rao, D.S.

    1989-01-01

    Details of seismic data acquisition systems developed at the Bhabha Atomic Research Centre, Bombay are reported. The seismic signals acquired belong to different signal bandwidths in the band from 0.02 Hz to 250 Hz. All these acquisition systems are built around a unique technique of recording multichannel data on to a single track of an audio tape and in digital form. Techniques of how these signals in different bands of frequencies were acquired and recorded are described. Method of detecting seismic signals and its performance is also discussed. Seismic signals acquired in different set-ups are illustrated. Time indexing systems for different set-ups and multichannel waveform display systems which form essential part of the data acquisition systems are also discussed. (author). 13 refs., 6 figs., 1 tab

  3. PSMG switchgear seismic analysis

    International Nuclear Information System (INIS)

    Kuehster, C.J.

    1977-01-01

    LOFT primary coolant system motor generator (PSMG) switchgear boxes were analyzed for sliding and overturning during a seismic event. Boxes are located in TAN-650, Room B-239, with the PSMG generators. Both boxes are sufficiently anchored to the floor

  4. Imported malaria in children in Madrid, Spain, 2007-2013.

    Science.gov (United States)

    Sánchez, Beatriz Soto; Tato, L M Prieto; Martín, S Guillén; Pérez, E; Grasa, C; Valderrama, S; Augusto, I de; Sierra, M; Ros, M García; Aguado, I; Hortelano, M García López

    The majority of malaria cases diagnosed in Europe in the last few years have occurred in people living in non-endemic areas travelling back to their home country to visit friends and relatives (VFRs). Children account for 15-20% of imported malaria, with known higher risk of severe disease. A retrospective multicentre study was conducted in 24 hospitals in Madrid (Spain) including patients under 16 years diagnosed with malaria (2007-2013). A total of 149 episodes in 147 children were reported. Plasmodium falciparum was the species most commonly isolated. Twenty-five patients developed severe malaria and there was one death related to malaria. VFR accounted for 45.8% of our children. Only 17 VFRs had received prophylaxis, and 4 of them taken appropriately. They presented more frequently with fever (98% vs. 69%), a longer time with fever (55 vs. 26%), delay in diagnosis of more than three days (62 vs. 37%), and more thrombocytopenia (65 vs. 33%) than non-VFRs, and with significant differences (pmalaria cases in our study. They seldom took adequate prophylaxis, and delayed the visit to the physician, increasing the length of fever and subsequent delaying in diagnosis. Appropriate preventive measures, such as education and pre-travel advices should be taken in this population. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  5. Hydrothermal behaviour of sedimentary saponitic clays from Madrid Basin

    International Nuclear Information System (INIS)

    Cuevas Rodriguez, J.

    1993-01-01

    The hydrothermal behavior of sedimentary saponitic clays from Madrid Basin has been investigated to assess their potential use as a buffer material in high level radioactive waste repositories. This paper deals with a review of several aspects that has been studied: the adsorption and irreversible fixation of K'+, the alteration in absence of potassium and the effects of heat and steam on textural properties of the smectitic clay. Experiments have covered temperatures up to 175 degree centigree with an excess of liquid water except on the last subject. Chemical and XRD analyses of final clay products and solutions indicates minor alteration of the saponite in the hydrothermal experiments either in the presence or absence of potassium. No illitization or chloritization processes seems to affect the smectite. Sepiolite was found to be largely dissolved at 175 degree centigree, a process that inhibited recrystallization or formation of illite observed when illite was present in significant amounts in starting materials. Accessory minerals (illite and sepiolite) accompanying as traces the saponitic material underwent and intense degradation at 175 degree centigree in absence of potassium. On the other hand, clay steamed at 200 degree centigree showed significant textural changes forming highly stable silt size aggregates which hindered the swelling abilities of the saponitic material, a fact that was previously observed in montmorillonites. (Author) 25 refs

  6. La imagen alfonsina del Palacio Real de Madrid

    Directory of Open Access Journals (Sweden)

    José Luis Sancho

    1990-01-01

    Full Text Available A finales del siglo XIX el Palacio Real de Madrid sufrió una reforma que supuso un cambio importante en el aspecto interior de esta residencia real. En 1879 y con el segundo matrimonio de Alfonso XII como causa inmediata, la decoración se puso al servicio de una escenografía monárquica bastante diferente a la isabelina. Los cambios no fueron en absoluto puntuales, sino que respondieron a una campaña global y pensada de una vez, cuyas cabezas más destacadas fueron el arquitecto mayor de Palacio, José Segundo de Lema, y el conde de Valencia de Don Juan como asesor histórico-artístico, y que estaba en perfecto acuerdo con el momento político y el gusto de su momento. La restauración alfonsina, ya consolidada, exigía una imagen oficial de la monarquía en la cual el lujo inherente a la representación no podía quedar encerrado en perpetuar la pompa dieciochesca, según había señalado un publicista tan notable como Galdós.

  7. Complejo parroquial de Santa Ana, en Moratalaz, Madrid

    Directory of Open Access Journals (Sweden)

    Fisac, Miguel

    1967-06-01

    Full Text Available This church is sited at Moratalaz, a modern district of low rent houses in Madrid, and the architect has attempted to represent in the design the liturgical concepts developed in the Vatican II Council. These precise ideas have been expressed in the architecture by means of highly plastic symbols. In addition, the planform is very functional and the reinforced and prestressed concrete have been almost the only material used: so that the construction medium is also in accord with the modern nature of the design. The shapes, the space arrangement and everything which might seem a capricious creation of the artist in fact are the result of a detailed analysis of function and reason.Este complejo parroquial se ha levantado en Moratalaz, que es un barrio popular de la capital de España, procurando imprimir y recoger todas las premisas litúrgicas marcadas por el Concilio Vaticano II. El arquitecto ha plasmado sus precisas ideas en un edificio de gran expresividad plástica y de planta orgánica y eficaz, utilizando, casi exclusivamente, un material de nuestro tiempo: hormigón armado y pretensado. Las formas, la disposición de espacios y todo cuanto puede parecer caprichosa creación del artista, no son, en realidad, sino resultado de un cuidadoso estudio de funcionalismo racional y utilitario.

  8. [Health behavior of schoolchildren in a metropolitan area of Madrid].

    Science.gov (United States)

    Andradas Aragonés, V; Fernández San Martín, I M

    1994-01-01

    To describe health behavior of students about diet, alcohol and tobacco, dental-oral hygiene, leisure time activities and interpersonal relations. 942 Students have been carried out. Children come from six schools of the town of Parla (in the south of Madrid). They are from 9 to 14 years old. The instruments have been made for this study, helping by teachers of EGB. 50% of the students doesn't eat any food at 12 o'clock, after drinking a glass of milk only at breakfast (8 o'clock). 10% never eats greens. 37% of the children in the upper level drinks alcohol sometimes and, in the same level, 12% smokes sometimes. Around 25% of children brush their teeth three times in the day. The students watch television three hours and half, means, in the day. The communication with the teacher is evaluated from "not too bad" to "bad" by 70% of the students of upper level. 42% and 39.4% of the children talks about abortion and contraceptives, respectively, with nobody. In general, girls have better habits than boys. Only exercise is more prevalent in the boys than in the girls.

  9. Soil Properties Database of Spanish Soils. Volume V.- Madrid

    International Nuclear Information System (INIS)

    Trueba, C.; Millan, R.; Schmid, T.; Roquero, C.; Magister, M.

    1998-01-01

    The soil vulnerability determines the sensitivity of the soil after an accidental radioactive contamination due to Cs-137 and Sr-90. The Departamento de Impacto Ambiental de la Energia of CIEMAT is carrying out an assessment of the radiological vulnerability of the different Spanish soils found on the Iberian Peninsula. This requires the knowledge of the soil properties for the various types of existing soils. In order to achieve this aim, a bibliographical compilation of soil profiles has been made to characterize the different soil types and create a database of their properties. Depending on the year of publication and the type of documentary source, the information compiled from the available bibliography is very heterogeneous. Therefore, an important effort has been made to normalize and process the information prior to its incorporation to the database. This volume presents the criteria applied to normalize and process the data as well as the soil properties of the various soil types belonging to the Comunidad Autonoma de Madrid. (Author) 39 refs

  10. The CSN hosts the Second International Conference on Nuclear Security in Madrid; El CSN acoge en Madrid la Segunda Conferencia Internacional de Seguridad Fisica Nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Scialdone Garcia, A.

    2016-08-01

    The second International Conference on Nuclear Security was held in Madrid between May 9th and 13th last. The acting Minister of the Interior announced that the number of officers of the Guardia Civil watching over the Spanish nuclear power plants will be doubled. (Author)

  11. Bioclimatic buildings of 16 houses in Pozuelo de Alarcon (Madrid); Edificio bioclimatico de 16 viviendas de promocion publica pra jovenes en Pozuelo de Alarcon. (Madrid)

    Energy Technology Data Exchange (ETDEWEB)

    Yanez, G.; Yanez-Lopez del Amo, L.

    2004-07-01

    We present in this article a housing building for young people recently built for the Autonomous Administration of Madrid in Pozuelo de Alarcon in which have been applied some bioclimatic and energy efficiency techniques. In this communication are described the main architectural features and are exposed some of the estimated results of energy saving and reduction of Co2. (Author)

  12. Building with 54 houses of high energetical efficiency in Madrid; Edificio de 54 viviendas de alta eficiencia energetica en el oeste de San Fermin. Parclea 5 (Madrid)

    Energy Technology Data Exchange (ETDEWEB)

    Yanez, G.; Yanez-Lopez del Amo, L.

    2004-07-01

    We present in this article a residential building recently built in Madrid for the EMV in which have been applied some bioclimatic and energy efficiency techniques. In this communication are described the main architectural features and are exposed some of the estimated results of energy saving with the contribution of solar energy in passive space and water heating. (Author)

  13. Improving fault image by determination of optimum seismic survey parameters using ray-based modeling

    Science.gov (United States)

    Saffarzadeh, Sadegh; Javaherian, Abdolrahim; Hasani, Hossein; Talebi, Mohammad Ali

    2018-06-01

    In complex structures such as faults, salt domes and reefs, specifying the survey parameters is more challenging and critical owing to the complicated wave field behavior involved in such structures. In the petroleum industry, detecting faults has become crucial for reservoir potential where faults can act as traps for hydrocarbon. In this regard, seismic survey modeling is employed to construct a model close to the real structure, and obtain very realistic synthetic seismic data. Seismic modeling software, the velocity model and parameters pre-determined by conventional methods enable a seismic survey designer to run a shot-by-shot virtual survey operation. A reliable velocity model of structures can be constructed by integrating the 2D seismic data, geological reports and the well information. The effects of various survey designs can be investigated by the analysis of illumination maps and flower plots. Also, seismic processing of the synthetic data output can describe the target image using different survey parameters. Therefore, seismic modeling is one of the most economical ways to establish and test the optimum acquisition parameters to obtain the best image when dealing with complex geological structures. The primary objective of this study is to design a proper 3D seismic survey orientation to achieve fault zone structures through ray-tracing seismic modeling. The results prove that a seismic survey designer can enhance the image of fault planes in a seismic section by utilizing the proposed modeling and processing approach.

  14. Broadband Seismic Studies at the Mallik Gas Hydrate Research Well

    Science.gov (United States)

    Sun, L. F.; Huang, J.; Lyons-Thomas, P.; Qian, W.; Milkereit, B.; Schmitt, D. R.

    2005-12-01

    The JAPEX/JNOC/GSC et al. Mallik 3L-38, 4L-38 and 5L-38 scientific wells were drilled in the MacKenzie Delta, NWT, Canada in early 2002 primarily for carrying out initial tests of the feasibility of producing methane gas from the large gas hydrate deposits there [1]. As part of this study, high resolution seismic profiles, a pseudo-3D single fold seismic volume and broadband (8~180Hz) multi-offset vertical seismic profiles (VSP) were acquired at the Mallik site. Here, we provide details on the acquisition program, present the results of the 2D field profile, and discuss the potential implications of these observations for the structure of the permafrost and gas hydrate zones. These zones have long been problematic in seismic imaging due to the lateral heterogeneities. Conventional seismic data processing usually assume a stratified, weak-contrast elastic earth model. However, in permafrost and gas hydrate zones this approximation often becomes invalid. This leads to seismic wave scattering caused by multi-scale perturbation of elastic properties. A 3D viscoelastic finite difference modeling algorithm was employed to simulate wave propagation in a medium with strong contrast. Parameters in this modeling analysis are based on the borehole geophysical log data. In addition, an uncorrelated Vibroseis VSP data set was studied to investigate frequency-dependent absorption and velocity dispersion. Our results indicate that scattering and velocity dispersion are important for a better understanding of attenuation mechanisms in heterogeneous permafrost and gas hydrate zones. [1] Dallimore, S.R., Collett, T.S., Uchida, T., and Weber, M., 2005, Overview of the science program for the Mallik 2002 Gas Hydrate Production Research Well Program; in Scientific Results from Mallik 2002 Gas Hydrate production Research Well Program, MacKenzie Delta, Northwest Territories, Canada, (ed.) S.R. Dallimore and T.S. Collett; Geological Survey of