ALBERT

Beschreibung:    We investigated the development of a distinct later phase observed at stations near the Japan Trench associated with shallow, outer-rise earthquakes off the coast of Sanriku, northern Japan based on the analysis of three-component broadband seismograms and FDM simulations of seismic wave propagation using a heterogeneous structural model of the Japan Trench subduction zone. Snapshots of seismic wave propagation obtained through these simulations clearly demonstrate the complicated seismic wavefield constructed by a coupling of the ocean acoustic waves and the Rayleigh waves propagating within seawater and below the sea bottom by multiple reflections associated with shallow subduction zone earthquakes. We demonstrated that the conversion to the Rayleigh wave from the coupled ocean acoustic waves and the Rayleigh wave as they propagate upward along the slope of seafloor near the coast is the primary cause of the arrival of the distinct later phase at the station near the coast. Through a sequence of simulations using different structural models of the Japan Trench subduction zone, we determined that the thick layer of seawater along the trench and the suddenly rising sea bottom onshore of the Japanese island are the major causes of the distinct later phase. The results of the present study indicate that for realistic modeling of seismic wave propagation from the subduction zone earthquakes, a high-resolution bathymetry model is very crucial, although most current simulations do not include a water column in their simulation models. Content Type Journal Article Pages 1-14 DOI 10.1007/s00024-011-0412-1 Authors Shinako Noguchi, Center for Integrated Disaster Information Research, Interfaculty Initiative in Information Studies, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-0033 Japan Takuto Maeda, Center for Integrated Disaster Information Research, Interfaculty Initiative in Information Studies, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-0033 Japan Takashi Furumura, Center for Integrated Disaster Information Research, Interfaculty Initiative in Information Studies, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-0033 Japan Journal Pure and Applied Geophysics Online ISSN 1420-9136 Print ISSN 0033-4553

Beschreibung:    The Algarve province is located a few hundred kilometres north of the crossing of the E–W Eurasia–Africa plate boundary in an area of diffuse seismicity and broad deformation. It is characterised by a moderate seismicity, with some important historical and instrumental earthquakes causing loss of lives and significant material damages. The area is affected not only by plate boundary earthquakes but also by moderate to large events generated by local sources. The assessment of onshore local sources is, therefore, of vital importance for an evaluation of the regional seismic hazard. This paper discusses the application of geophysical data to the study of the Carcavai fault zone, an outcropping structure more than 20 km long which is seen to deform sediments of the Plio-Quaternary age. The location of some sectors of the fault zone, as well as the vertical offsets of the structure, are still to be confirmed. In order to estimate these and to study the geometry of the fault zone at depth, geophysical data were acquired together with new geological data. Where the location of the fault was less certain, EM and seismic reflection profiles with coarse spatial sampling were carried out. After the detailed location of the fault zone, seismic reflection profiles with a more dense spatial resolution were acquired. The integrated interpretation of the geological and geophysical data confirmed the presence of a large fault zone. The total fault length is still unknown as its extension offshore is still being studied. Together with estimated values of the throw obtained, this data set has improved understanding the seismic hazard in the area by providing more refined estimates of co-seismic rupture, maximum expected earthquake and return periods. Content Type Journal Article Pages 1-18 DOI 10.1007/s00024-011-0318-y Authors J. Carvalho, Laboratório Nacional de Energia e Geologia, Alfragide, Portugal E. Ramalho, Laboratório Nacional de Energia e Geologia, Alfragide, Portugal R. Dias, Laboratório Nacional de Energia e Geologia, Alfragide, Portugal C. Pinto, Laboratório Nacional de Energia e Geologia, Alfragide, Portugal R. Ressurreição, Laboratório Nacional de Energia e Geologia, Alfragide, Portugal Journal Pure and Applied Geophysics Online ISSN 1420-9136 Print ISSN 0033-4553

Beschreibung:    Dew samples were collected between October 2007 and February 2008 from a suburban site in Agra. pH, conductivity, major inorganic ions (F − , Cl − , NO 3 − , SO 4 2− , Na + , K + , Ca 2+ , Mg 2+ , and NH 4 + ), and some trace metals (Cr, Sn, Zn, Pb, Cd, Ni, Mn, Fe, Si, Al, V, and Cu) were determined to study the chemistry of dew water. The mean pH was 7.3, and the samples exhibited high ionic concentrations. Dew chemistry suggested both natural and anthropogenic influences, with acidity being neutralized by atmospheric ammonia and soil constituents. Ion deposition flux varied from 0.25 to 3.0 neq m −2  s −1 , with maximum values for Ca 2+ followed by NH 4 + , Mg 2+ , SO 4 2− , Cl − , NO 3 − , Na + , K + , and F − . Concentrations of trace metals varied from 0.13 to 48 μg l −1 with maximum concentrations of Si and minimum concentration of Cd. Correlation analysis suggested their contributions from both crustal and anthropogenic sources. Content Type Journal Article Pages 1-13 DOI 10.1007/s00024-011-0329-8 Authors Anita Lakhani, Department of Chemistry, Dayalbagh Educational Institute, Dayalbagh, Agra, India Ravindra Singh Parmar, Department of Chemistry, Dayalbagh Educational Institute, Dayalbagh, Agra, India Satya Prakash, Department of Chemistry, Dayalbagh Educational Institute, Dayalbagh, Agra, India Journal Pure and Applied Geophysics Online ISSN 1420-9136 Print ISSN 0033-4553

Beschreibung:    The eastern Pontides orogenic belt is one of the most complex geodynamic settings in the Alpine–Himalayan belt due to the lack of systematical geological and geophysical data. In this study, 1D crustal structure and P-wave velocity distribution obtained from gravity modeling and seismological data in the area has been used for the development of the thermal model of the eastern Pontides orogenic belt. The computed temperature-depth profiles suggest a temperature of 590 ± 60°C at a Moho depth of 35 km indicates the presence of a brittle-ductile transition zone. This temperature value might be related to water in the subducted crust of the Tethys oceanic lithosphere. The Curie temperature depth value of 29 km, which may correspond to the crustal magma chambers, is found 5–7 km below the Moho depth. Surface heat flow density values vary from 66.5 and 104.7 mW m −2 . High mantle heat flow density value of 48 mW m −2 is obtained for the area should be related to melting of the lithospheric mantle caused by upwelling of asthenosphere. Content Type Journal Article Pages 1-14 DOI 10.1007/s00024-011-0296-0 Authors Nafiz Maden, Department of Geophysics, Gümüşhane University, 29100 Gümüşhane, Turkey Journal Pure and Applied Geophysics Online ISSN 1420-9136 Print ISSN 0033-4553

Beschreibung:    Operational prediction of near-field tsunamis in all existing Tsunami Warning Systems (TWSs) is based on fast determination of the position and size of submarine earthquakes. Exceedance of earthquake magnitude above some established threshold value, which can vary over different tsunamigenic zones, results in issuing a warning signal. Usually, a warning message has several (from 2 to 5) grades reflecting the degree of tsunami danger and sometimes contains expected wave heights at the coast. Current operational methodology is based on two main assumptions: (1) submarine earthquakes above some threshold magnitude can generate dangerous tsunamis and (2) the height of a resultant tsunami is, in general, proportional to the earthquake magnitude. While both assumptions are physically reasonable and generally correct, statistics of issued warnings are far from being satisfactory. For the last 55 years, up to 75% of warnings for regional tsunamis have turned out to be false, while each TWS has had at least a few cases of missing dangerous tsunamis. This paper presents the results of investigating the actual dependence of tsunami intensity on earthquake magnitude as it can be retrieved from historical observations and discusses the degree of correspondence of the above assumptions to real observations. Tsunami intensity, based on the Soloviev-Imamura scale is used as a measure of tsunami “size”. Its correlation with the M s and M w magnitudes is investigated based on historical data available for the instrumental period of observations (from 1900 to present). Content Type Journal Article Pages 1-9 DOI 10.1007/s00024-011-0286-2 Authors Viacheslav K. Gusiakov, Institute of Computational Mathematics and Mathematical Geophysics, Siberian Division, Russian Academy of Sciences, Pr Lavrentieva, 6, Novosibirsk, 630090 Russia Journal Pure and Applied Geophysics Online ISSN 1420-9136 Print ISSN 0033-4553

Beschreibung:    The micromechanical damage mechanics formulated by A shby and S ammis (Pure Appl Geophys 133(3) 489–521, 1990 ) has been shown to give an adequate description of the triaxial failure surface for a wide variety of rocks at low confining pressure. However, it does not produce the large negative curvature in the failure surface observed in Westerly granite at high confining pressure. We show that this discrepancy between theory and data is not caused by the two most basic simplifying assumptions in the damage model: (1) that all the initial flaws are the same size or (2) that they all have the same orientation relative to the largest compressive stress. We also show that the stress–strain curve calculated from the strain energy density significantly underestimates the nonlinear strain near failure in Westerly granite. Both the observed curvature in the failure surface and the nonlinear strain at failure observed in Westerly granite can be quantitatively fit using a simple bi-mineral model in which the feldspar grains have a lower flow stress than do the quartz grains. The conclusion is that nonlinearity in the failure surface and stress–strain curves observed in triaxial experiments on Westerly granite at low loading rates is probably due to low-temperature dislocation flow and not simplifying assumptions in the damage mechanics. The important implication is that discrepancies between experiment and theory should decrease with increased loading rates, and therefore, the micromechanical damage mechanics, as formulated, can be expected to give an adequate description of high strain-rate phenomena like earthquake rupture, underground explosions, and meteorite impact. Content Type Journal Article Pages 1-18 DOI 10.1007/s00024-011-0271-9 Authors H. S. Bhat, Department of Earth Sciences , 3651 Trousdale Parkway, Los Angeles, CA 90089, USA C. G. Sammis, Department of Earth Sciences , 3651 Trousdale Parkway, Los Angeles, CA 90089, USA A. J. Rosakis, Graduate Aerospace Laboratories, 1200 E. California Blvd., Pasadena, CA 91125, USA Journal Pure and Applied Geophysics Online ISSN 1420-9136 Print ISSN 0033-4553

Beschreibung:    Almost 5 years after the 26 December 2004 Indian Ocean tragedy, the 10 August 2009 Andaman tsunami demonstrated that accurate forecasting is possible using the tsunami community modeling tool Community Model Interface for Tsunamis (ComMIT). ComMIT is designed for ease of use, and allows dissemination of results to the community while addressing concerns associated with proprietary issues of bathymetry and topography. It uses initial conditions from a precomputed propagation database, has an easy-to-interpret graphical interface, and requires only portable hardware. ComMIT was initially developed for Indian Ocean countries with support from the United Nations Educational, Scientific, and Cultural Organization (UNESCO), the United States Agency for International Development (USAID), and the National Oceanic and Atmospheric Administration (NOAA). To date, more than 60 scientists from 17 countries in the Indian Ocean have been trained and are using it in operational inundation mapping. Content Type Journal Article Pages 1-11 DOI 10.1007/s00024-011-0292-4 Authors V. V. Titov, NOAA/Pacific Marine Environmental Laboratory, 7600 Sand Point Way NE, Seattle, WA 98115-6349, USA C. W. Moore, Joint Institute for the Study of the Atmosphere and Ocean (JISAO), University of Washington, Box 357941, Seattle, WA 98195-4235, USA D. J. M. Greenslade, Centre for Australian Weather and Climate Research, Bureau of Meteorology, GPO Box 1289, Melbourne, VIC 3001, Australia C. Pattiaratchi, School of Environmental Systems Engineering, The University of Western Australia, Mailstop MO15, 35, Stirling Highway, Crawley, WA 6009, Australia R. Badal, Mauritius Oceanography Institute, France Centre, Quatre Bornes, Mauritius C. E. Synolakis, Viterbi School of Engineering, University of Southern California, Los Angeles, CA 90089-2531, USA U. Kânoğlu, Department of Engineering Sciences, Middle East Technical University, 06531 Ankara, Turkey Journal Pure and Applied Geophysics Online ISSN 1420-9136 Print ISSN 0033-4553

Beschreibung:    We study singular elastic solutions at an angular corner left by a crack that has kinked. We have in mind a geophysical context where the faults on either side of the kink are under compression and are ready to slip, or have already slipped, under the control of Coulomb friction. We find separable static singular solutions that are matched across the sides of the corner by applying appropriate boundary conditions. In our more general solution we assume that one of the sides of the corner is about to slide, i.e. it is just contained by friction, and the other may be less pressured. Our solutions display power law behaviour with real exponents that depend continuously on the angle of the corner, the coefficient of static friction and the difference of shear load on both sides of the corner. When friction is the same on both sides of the kink, the solutions split into a symmetric and an antisymmetric solution. The antisymmetric solution corresponds to the simple shear case; while the symmetric solution appears when the kink is loaded by uniaxial stress along the bisector of the kink. The antisymmetric solution is ruled out under this model with contact since the faults cannot sustain tension. When one side of the corner is less pressured one can also distinguish modes with contact overall from others that must open up on one side. These solutions provide an insight into the stress distributions near fault kinks, they can also be used as tools for improving the numerical calculation of kinks under static or dynamic loads. Content Type Journal Article Pages 1-13 DOI 10.1007/s00024-011-0298-y Authors Rodrigo Arias, Departamento de Física, FCFM, Universidad de Chile, Santiago, Chile Raúl Madariaga, Laboratoire de géologie, CNRS-École Normale Supérieure, Paris, France Mokhtar Adda-Bedia, Laboratoire de physique statistique, CNRS-École Normale Supérieure, Paris, France Journal Pure and Applied Geophysics Online ISSN 1420-9136 Print ISSN 0033-4553

Beschreibung:    Intensive field experiments focused on fog chemistry were carried out in the northern suburb of Nanjing during the winters of 2006 and 2007. Thirty-seven fog water samples were collected in nine fog events. Based on the chemical analysis results of those samples and the simultaneous measurements of air pollution gases and atmospheric aerosols, the chemical characteristics of fog water and their relations with air pollutants during fog evolution were investigated. The results revealed an average total inorganic ionic concentration TIC = 21.18 meq/L, and the top three ion concentrations were those of SO 4 2− , NH 4 + and Ca 2+ (average concentrations 6.99, 5.95, 3.77 meq/L, respectively). However, the average pH value of fog water was 5.85, which is attributable to neutralization by basic ions (NH 4 + and Ca 2+ ). The average TIC value of fog water measured in advection–radiation fog was around 2.2 times that in radiation fog, and the most abundant cation was NH 4 + in advection–radiation fog and Ca 2+ in radiation fog. In dense fog episodes, the concentration variations of primary inorganic pollution gases showed a “V”-shaped pattern, while those of volatile organic compounds (VOCs) displayed a “Λ”-shaped pattern. The dense fog acted as both the source and sink of atmospheric aerosol particles; fog processes enhanced particle formation, leading to the phenomenon that the aerosol concentration after fog dissipation was higher than that before the fog, and at the same time, mass concentration of PM 10 reached the lowest value in the late stage of extremely dense fog episodes because of the progressive accumulated effect of wet deposition of large fog droplets. Both air pollution gases and aerosols loading controlled the ion compositions of fog water. The Ca 2+ in fog water originated from airborne particles, while SO 4 2− and NH 4 + were from both heterogeneous production and soluble particulate species. Content Type Journal Article Pages 1-16 DOI 10.1007/s00024-011-0342-y Authors Jun Yang, Key Laboratory of Atmospheric Physics and Environment, School of Atmospheric Physics, Nanjing University of Information Science and Technology, No. 219 Ningliu Road, Nanjing, 210044 China Yu-Jing Xie, Key Laboratory of Atmospheric Physics and Environment, School of Atmospheric Physics, Nanjing University of Information Science and Technology, No. 219 Ningliu Road, Nanjing, 210044 China Chun-E Shi, Anhui Institute of Meteorological Sciences, Hefei, 230031 China Duan-Yang Liu, Key Laboratory of Atmospheric Physics and Environment, School of Atmospheric Physics, Nanjing University of Information Science and Technology, No. 219 Ningliu Road, Nanjing, 210044 China Sheng-Jie Niu, Key Laboratory of Atmospheric Physics and Environment, School of Atmospheric Physics, Nanjing University of Information Science and Technology, No. 219 Ningliu Road, Nanjing, 210044 China Zi-Hua Li, Key Laboratory of Atmospheric Physics and Environment, School of Atmospheric Physics, Nanjing University of Information Science and Technology, No. 219 Ningliu Road, Nanjing, 210044 China Journal Pure and Applied Geophysics Online ISSN 1420-9136 Print ISSN 0033-4553

Beschreibung:    The coupled mechanics of fluid-filled granular media controls the physics of many Earth systems, for example saturated soils, fault gouge, and landslide shear zones. It is well established that when the pore fluid pressure rises, the shear resistance of fluid-filled granular systems decreases, and, as a result, catastrophic events such as soil liquefaction, earthquakes, and accelerating landslides may be triggered. Alternatively, when the pore pressure drops, the shear resistance of these geosystems increases. Despite the great importance of the coupled mechanics of grain–fluid systems, the basic physics that controls this coupling is far from understood. Fundamental questions that must be addressed include: what are the processes that control pore fluid pressurization and depressurization in response to deformation of the granular skeleton? and how do variations of pore pressure affect the mechanical strength of the grains skeleton? To answer these questions, a formulation for the pore fluid pressure and flow has been developed from mass and momentum conservation, and is coupled with a granular dynamics algorithm that solves the grain dynamics, to form a fully coupled model. The pore fluid formulation reveals that the evolution of pore pressure obeys viscoelastic rheology in response to pore space variations. Under undrained conditions elastic-like behavior dominates and leads to a linear relationship between pore pressure and overall volumetric strain. Viscous-like behavior dominates under well-drained conditions and leads to a linear relationship between pore pressure and volumetric strain rate. Numerical simulations reveal the possibility of liquefaction under drained and initially over-compacted conditions, which were often believed to be resistant to liquefaction. Under such conditions liquefaction occurs during short compactive phases that punctuate the overall dilative trend. In addition, the previously recognized generation of elevated pore pressure under undrained compactive conditions is observed. Simulations also show that during liquefaction events stress chains are detached, the external load becomes completely supported by the pressurized pore fluid, and shear resistance vanishes. Content Type Journal Article Pages 1-35 DOI 10.1007/s00024-011-0320-4 Authors L. Goren, Institute of Earth Sciences, Hebrew University, Givat Ram, Jerusalem, Israel E. Aharonov, Institute of Earth Sciences, Hebrew University, Givat Ram, Jerusalem, Israel D. Sparks, Department of Geology and Geophysics, Texas A&M University, College Station, TX, USA R. Toussaint, Institut de Physique du Globe de Strasbourg (IPGS), CNRS and University of Strasbourg (EOST), Strasbourg, France Journal Pure and Applied Geophysics Online ISSN 1420-9136 Print ISSN 0033-4553