Download or read book Shallow Subduction Zones Seismicity Mechanics and Seismic Potential Part 1 written by DMOWSKA and published by Birkhäuser. This book was released on 2013-11-21 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reprint from Pure and Applied Geophysics (PAGEOPH), Volume 140 (1993), No. 2

Download or read book Shallow subduction zones written by Renata Dmowska and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Shallow Subduction Zones written by Renata Dmowska and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Shallow Subduction Zones written by and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Shallow Subduction Zones Seismicity Mechanics and Seismic Potential written by Renata Dmowska and published by Birkhäuser. This book was released on 2012-12-06 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reprint from Pure and Applied Geophysics (PAGEOPH), Volume 142 (1994), No. 1

Download or read book Shallow Subduction Zones written by Renata Dmowska and published by . This book was released on 1993 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mechanics Problems in Geodynamics Part I written by Ren Wang and published by Birkhäuser. This book was released on 2012-12-06 with total page 381 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geodynamics concerns with the dynamics of the global motion of the earth, of the motion in the earth's interior and its interaction with surface features, together with the mechanical processes in the deformation and rupture of geological structures. Its final object is to determine the driving mechanism of these motions which is highly interdisciplinary. In preparing the basic geological, geophysical data required for a comprehensive mechanical analysis, there are also many mechanical problems involved, which means the problem is coupled in a complicated manner with geophysics, rock mechanics, seismology, structural geology etc. This topical issue is Part I of the Proceedings of an IUTAM / IASPEI Symposium on Mechanics Problems in Geodynamics held in Beijing, September 1994. It addresses different aspects of mechanics problems in geodynamics involving tectonic analyses, lithospheric structures, rheology and the fracture of earth media, mantle flow, either globally or regionally, and either by forward or inverse analyses or numerical simulation.

Download or read book Mechanics problems in geodynamics 1 1995 written by Ren Wang and published by Springer Science & Business Media. This book was released on 1995 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of two volumes of the proceedings of a symposium held in Beijing in September 1994. The 20 papers cover general global problems, mantel convection and subduction, regional tectonic problems, earthquake mechanisms, and the mechanical properties of rock fractures. Well illustrated. No index. Also published in Pageoph v.145, no.3/4. Annotation copyright by Book News, Inc., Portland, OR

Download or read book New Publications of the U S Geological Survey written by and published by . This book was released on 1994 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book New Publications of the U S Geological Survey written by Geological Survey (U.S.) and published by . This book was released on 1994 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Seismic Waves in Laterally Inhomogeneous Media Part II written by Ivan Psencik and published by Birkhäuser. This book was released on 2012-12-06 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: The special issue contains contributions presented at the international workshop Seismic waves in laterally inhomogeneous media IV, which was held at the Castle of Trest, Czech Republic, May 22-27, 1995. The workshop, which was attended by about 100 seismologists from more than 10 countries, was devoted mainly to the current state of theoretical and computational means of study of seismic wave propagation in complex structures. The special issue can be of interest for theoretical, global and explorational seismologists. The first part contains papers dealing with the study and the use of various methods of solving forward and inverse problems in complicated structures. Among other methods, discrete-wave number method, the finite-difference method, the edge-wave supperposition method and the ray method are studied and used. Most papers contained in the second part are related to the ray method. The most important topics are two-point ray tracing, grid calculations of travel times and amplitudes and seismic wave propagation in anisotropic media.

Download or read book Tsunamis 1992 1994 written by Kenji Satake and published by Birkhäuser. This book was released on 2012-12-06 with total page 511 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 1993 Southwest Hokkaido Earthquake of Magnitude 7. 9 (July 12, 22: 17 JST) caused serious tsunami disasters in the southwestern part of Hokkaido, particularly on Okushiri Island (a tiny island off the southwest coast of Hokkaido with a population of about 4,500 at the time of earthquake). Of 230 casualties, including 28 missing, about 200 deaths are attributable to the tsunami. We have conducted detailed field surveys of tsunami disasters to learn lessons from this costly natural experiment for the future prevention of similar tsunami disasters. Our field work was conducted in four surveys totaling 39 days. During the first field survey (July 16 through July 21, 1994), we worked mostly on the estimation of the subsidence of Okushiri Island during the earthquake. Hence, our main work on tsunami disasters initiated from the second field survey (July 31 through Aug. 15, 1994). Several groups have conducted detailed surveys of the distribution of tsunami runup height as measured from the level of sea water (TsUJI et al. , 1 994a, b; MATSUTOMI and SHUTO, 1994; GOTO et al. , 1994). Such a precise runup height distribution is essential for characterizing tsunami, including its overall size. Indeed, the height distribution is the fundamental data for inferring earthquake source parameters through the simulation of tsunami generation (TAKAHASHI et al. , 1994; IMAMURA et al. , 1994; TSUJI et al. , 1994a; SATAKE and TANIOKA 1994; ABE, 1994; TANIOKA et al. , in review).

Download or read book Induced Seismicity written by Harsh K. Gupta and published by Springer. This book was released on 2012-12-06 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: A workshop on Induced Seismicity was organized during the 27th General Assembly of the International Association of Seismology and Physics of Earth's Interior (IASPEI) in Wellington, New Zealand during January 10-21, 1994. This volume presents a collection of 16 papers accepted for publication which accrued from this workshop. The first three papers address mining activity related to induced seismicity. The fourth paper deals with water injection induced seismic activity, while the remaining 12 papers treat several aspects of water reservoir induced earthquakes. Globally, the Koyna dam creating Shivajisagar Lake in Maharashtra, India, continues to be the most significant site of reservoir-induced earthquakes. With the increase in the number of cases of induced seismicity, there is a growing concern among planners, engineers, geophysicists and geologists to understand the environment conducive to this phenomenon. While the changes in pore-fluid pressure have been identified as the key factor in inducing earthquakes, the phenomenon itself is still poorly understood. This reality thus makes the study of the induced seismicity very important and this volume timely.

Download or read book Proceedings of Workshop XLVI the 7th U S Japan Seminar on Earthquake Prediction written by and published by . This book was released on 1990 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Induced Seismic Events written by Peter Knoll and published by Springer Science & Business Media. This book was released on 1996-07-30 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reprint from Pure and Applied Geophysics (PAGEOPH), Volume 147 (1996), No. 2

Download or read book Open file Report written by and published by . This book was released on 1990 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Seismic Potential of the Shallow Portions of the Northern Cascadia and the North Sumatra Subduction Zones written by Katja Stanislowski and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Many regions that are prone to experience strong earthquakes and tsunamis are densely populated, such as the coastlines of the Pacific Ocean and some of the Indian Ocean. These regions are subduction zone settings, where one tectonic plate subducts beneath another, which produces a gigantic fault - a megathrust fault. Subduction zone earthquakes largely occur on such megathrust faults. They have cost an incredible number of lives, and future events pose a constant threat to many more. Especially those megathrust earthquakes that nucleate in or propagate to very shallow depths can cause large damage and tsunamis. In general, the seismicity in the shallow portion of subduction zone megathrusts is low, but recent events such as the 2004 Aceh-Andaman earthquake and tsunami offshore North Sumatra have tragically shown the potential of shallow seismicity. Despite extensive investigations of multiple geoscientific disciplines, the shallow extent of earthquake rupture and slip of subduction zones around the world is still poorly constrained. Reasons for this lie in the challenging nature of such investigations, because the shallow extent of subduction zone earthquakes lies at sea and well below the ocean floor. Limited knowledge of this shallow earthquake extent reduces the chance of meaningful earthquake and tsunami hazard assessment and thus damage mitigation. Because earthquakes are friction phenomena, a large body of work in earthquake research is based on laboratory friction experiments. Early friction experiments have shown that repetitive frictionally unstable stick-slip sliding on artificial faults in the laboratory represents the small-scale equivalent of earthquakes on faults in nature. Friction on a fault evolves with velocity, slip, and time (rate- and state-dependent friction) and thus can lead to unstable sliding. Unstable sliding includes periods of fault locking and accumulation of elastic energy, with intermittent periods of fault rupture and slip, which releases the stored energy. The depth interval on the megathrust fault that is capable of unstable frictional sliding and thus earthquake nucleation is called the seismogenic zone. Crucial to estimating the extent of the seismogenic zone is knowledge of the variation of the velocity-dependent frictional behavior with depth. Especially the velocity-dependent frictional behavior at plate tectonic rate has shown to be crucial. This information can be derived from laboratory friction experiments and application of so-called rate- and state-friction laws. Ideally, such experiments should be conducted on fault-zone material. However, such material is difficult to obtain and its availability is very limited. Subduction zone input materials, which are the marine sedimentary column on the subducting plate, are less difficult to recover and hold important information on where a megathrust forms or what intrinsic frictional behavior the fault-forming material has. Measurements on input material are therefore a valuable alternative to measurements on fault zone material. This thesis presents the results of laboratory friction experiments at room temperature, under relatively low pressure, and driven at velocities starting from plate rate. These experiments were designed to investigate the frictional behavior of subduction zone input sediments and its implications on the fault slip behavior and seismic potential of the shallow portions of two subduction zones. The first is the northern Cascadia subduction zone, located along the West coast of North America, where a major earthquake is about to be due. The second is the North Sumatra subduction zone, a region of the Sunda subduction zone and the location of recent destructive earthquakes and tsunamis. At northern Cascadia, the megathrust has so far not been sampled. Based on measurements of frictional strength contrasts in the input sedimenatry column, we propose that the megathrust fault will likely form in a weak illite-rich hemipelagic clay near the top of the oceanic basement. Because this inference is in good agreement with interpretations of seismic imaging, we focused on the frictional behavior of this specific material. The absence of shallow non-destructive slow slip events at northern Cascadia has recently been interpreted to result from a megathrust that is locked and potentially seismogenic all the way to the trench. In contrast, the results presented in this work indicate that the shallow part of the megathrust is not capable of producing slow slip events nor capable of locking and thus likely not seismogenic. However, our friction data also indicate low resistance to a propagating earthquake nucleating at greater depth. This low resistance is evident from substantially elevated pore pressure, low frictional strength, and low cohesion. Therefore, the northern Cascadia subduction zone holds the potential of shallow earthquake slip and tsunamigenesis. At North Sumatra, seismic slip during the 2004 Aceh-Andaman subduction zone earthquake was unexpectedly shallow and resulted in a devastating tsunami. Recent work suggested that the cause is a very shallow seismogenic zone that may be created by diagenetic strengthening of fault-forming input sediments prior to subduction. This thesis presents the results of laboratory friction experiments designed to test this hypothesis. We showed that input sediments to the North Sumatra subduction zone exhibit pronounced frictional instability, offering evidence for a frictionally unstable and thus seismogenic shallow megathrust and thus an explanation for shallow earthquake slip in the 2004 event. However, our measurements indicate that the shallow megathrust is not seated in frictionally strong, but in very weak sediments. The combination of weak and unstable sediments is striking because a large number of previous friction studies have established that weak materials under low temperature and pressure conditions are generally associated with stable frictional sliding. This relationship offers an explanation for the observed general lack of seismicity in the shallow portion of subduction zone megathrusts, where unconsolidated, clay-rich, weak materials are typically encountered. We proposed that threshold amounts of dispersed hydrous amorphous silica in otherwise weak and clay-rich sediments are responsible for an unstable sliding character, which can explain the shallow seismicity at North Sumatra. To test the hypothesis that small amounts of hydrous amorphous silica induce unstable sliding behavior, we designed friction experiments on artificial mixtures of weak shale and biogenic opal, a type of hydrous amorphous silica. These experiments revealed pronounced potentially unstable behavior in mixtures with ≥ 30 % opal that had low frictional strength. Based on our results, we proposed that potential unstable sliding at low frictional strength can be explained by the viscous behavior of frictional contacts of hydrous amorphous silica. This highlights the necessity to reevaluate the strength-stability relationship. Our findings support the hypothesis on the role of hydrous amorphous silica in unstable sliding behavior, which has important implications for the potential of shallow seismogenesis at other subduction zones where input sediments contain critical amounts of hydrous amorphous silica. This thesis demonstrates that the northern Cascadia and the North Sumatra subduction zone have very different intrinsic frictional fault slip behavior despite very similar extrinsic properties and attributes, such as temperature or pressure. Thus, intrinsic factors are found to be crucial to the estimation of the slip behavior of shallow megathrust faults, such as a mineral composition of fault material with threshold amounts of hydrous amorphous silica. Hydrous amorphous silica-bearing sediments could form megathrust faults due to intrinsically low strength and potential of overpressure. The shallow portion of megathrust faults formed in such sediments may thus be able to host large and slow earthquakes. This could for instance be the case in the northern Barbados subduction zone, a setting that similar to the North Sumatra subduction zone has been shown to have a porous, overpressured décollement and predécollement consisting of material that contains elevated amounts of hydrous amorphous silica. Thus, this thesis raises the possibility that subduction zones with a shallow seismogenic zone may be more common than predicted by the seismogenic zone model. This inference implies that earthquake and tsunami hazards could be highly underestimated at some subduction zone settings.