Download or read book Experiments in Imaging Rupture Properties and Early Aftershocks of Large Earthquakes written by Peter M. Shearer and published by . This book was released on 2005* with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Imaging the Rupture Processes of Earthquakes Using the Relative Back Projection Method written by Hao Zhang and published by Springer. This book was released on 2017-12-27 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis adopts the relative back-projection method to dramatically reduce “swimming” artifacts by identifying the rupture fronts in the time window of a reference station; this led to a faster and more accurate image of the rupture processes of earthquakes. Mitigating the damage caused by earthquakes is one of the primary goals of seismology, and includes saving more people’s lives by devising seismological approaches to rapidly analyze an earthquake’s rupture process. The back-projection method described in this thesis can make that a reality.

Download or read book AutoBATS and 3D MUSIC New Approaches to Imaging Earthquake Rupture Behaviors written by Pei-Ru Jian and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the kinematic earthquake rupture studies from moment tenor to spatial-temporal rupture imaging. For real-time seismic hazard monitoring, the new stable automatic moment tensor (AutoBATS) algorithm is developed and implemented for the real-time MT reports by the Taiwan Earthquake Science Information System (TESIS). In order to understand the rupture behavior of the 2013 Mw 8.3 Okhotsk deep earthquake sequence, the 3D MUltiple SIgnal Classification Back Projection (MUSIC BP) with P and pP phases is applied. The combined P- and pP-wave BP imaging of the mainshock shows two stages of anti-parallel ruptures along two depths separating for about 10~15 km. Unusual super-shear ruptures are observed through the 3D BP images of two Mw 6.7 aftershocks. In last two chapters, the 3D BP imaging reveals similar rupture properties of two shallow catastrophic earthquakes (Mw=6.4) in southwestern Taiwan. Both the 2010 Jiashian and 2016 Meinong earthquakes ruptured westward with similar velocity of ~2.5 km/s along a NE-ward shallow dipping blind fault. The rupture similarities of the doublet suggest two parallel elongate asperities along the causative fault. After several decades of seismic quiescence, the 2010 Jiashian event initiated the rupture at the deeper asperity and triggered the shallower asperity which caused catastrophes six years later.

Download or read book Reconstruction of the Earthquake Rupture Process Through Coherent Teleseismic Imaging and Statistical Modeling written by Marina Corradini and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many studies have attempted to illuminate rupture complexities of large earthquakes through the use of coherent imaging techniques such as back-projection (BP). Recently, Fukahata et al. (2013) suggested that, from a theoretical point of view, the BP image of the rupture is related to the slip motion on the fault. However, the quantitative relationship between the BP images and the physical properties of the earthquake rupture process still remains unclear.Our work aims at clarifying how BP images of the radiated wavefield can be used to infer spatial heterogeneities in slip and rupture velocity along the fault. We simulate different rupture processes using a line source model. For each rupture model, we calculate synthetic seismograms at three teleseismic arrays and we apply the BP technique to identify the sources of high-frequency (HF) radiation. This procedure allows for the comparison of the BP images with the originating rupture model, and thus the interpretation of HF emissions in terms of along-fault variation of the three kinematic parameters: rise time, final slip, rupture velocity. Our results show that the HF peaks retrieved from BP analysis are most closely associated with space-time heterogeneities of slip acceleration. We verify our findings on two major earthquakes that occurred 9 years apart on the strike-slip Swan Islands fault: the Mw 7.3 2009 and the Mw 7.5 2018 North of Hondurasearthquakes. Both events followed a simple linear geometry, making them suitable for comparison with our synthetic approach. Despite the simple geometry, both slip-rate functions are complex, with several subevents. Our preliminary results show that the BP image of HF emissions allows to estimate a rupture length and velocity which are compatible with other studies and that strong HF radiation corresponds to the areas of large variability of the moment-rate function. An outstanding question is whether one can use the BP image of the earthquake to retrieve the kinematic parameters along the fault. We build on the findings obtained in the synthetic examples by training a neural network model to directly predict the kinematic parameters along the fault, given an input BP image. We train the network on a large number of different synthetic rupture processes and their BP images, with the goal of identifying the statistical link between HF radiation and rupture kinematic parameters. Our results show that the neural network applied to the BP image of the earthquake is able to predict the values of rise time and rupture velocity along the fault, as well as thecentral position of the heterogeneity, but not the absolute slip values, to which the HF BP approach is relatively insensitive. Our work sheds some light on the gap currently existing between the theoretical description of the generation of HF radiation and the observations of HF emissions obtained by coherent imaging techniques, tackling possible courses of action and suggesting new perspectives.

Download or read book Earthquake Rupture Imaging and Multiscale Stress Drop Estimation written by Bettina P. Allmann and published by ProQuest. This book was released on 2008 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Investigation of earthquake source parameters is important for better understanding of the physics behind earthquakes, which is essential for mitigating the hazards of destructive earthquakes. This dissertation explores several different aspects of source parameter estimation. First, I image the rupture process of the 2004 M6.0 Parkfield earthquake in three dimensions using a waveform back-projection method. I identify a distinct secondary high-frequency phase that radiated from a point about 13 km northwest of the hypocenter. Together with existing slip model inversions of the Parkfield earthquake, these results constrain several physical properties of the rupture process. Second, I use an iterative least-squares approach on both local and global seismic data to isolate source spectra from attenuation and near-station site effects and apply an empirical Green's function correction for near-source attenuation. Brune-type stress drop estimates for small earthquakes in the Parkfield area and for moderate to large earthquakes worldwide range from 0.1 to 50 MPa, with robust lateral variations in average stress drop. In Parkfield some of these variations change temporally after the 2004 M6.0 Parkfield earthquake. On a global scale, the stress drop variations are usually confined to specific plate boundaries or tectonic regimes. The highest average stress drops occur for oceanic transform fault earthquakes and other strike-slip events. Intraplate events have a factor of two higher average stress drops than interplate events. Stress drops of both small earthquakes in Parkfield and larger global earthquakes show no dependence on moment. Our stress-drop estimates, combined with other published results, provide strong evidence that earthquakes exhibit self-similarity over most of the instrumentally observable magnitude range. Finally, using the spectral separation method to discriminate between natural seismicity and man-made explosions, I find that the best single waveform discriminant for data recorded in southern California is the RMS-misfit between quarry blast spectra and an w-2 source model.

Download or read book Rupture Imaging of Large Earthquakes with a Poststack Isochrone Migration Method written by Frank Krüger and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Rupture Propagation Imaging Across Scales from Large Earthquakes to Microseismic Events written by Jonas T. Folesky and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Statistical Physics of Fracture Breakdown and Earthquake written by Soumyajyoti Biswas and published by John Wiley & Sons. This book was released on 2015-08-10 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, the authors bring together basic ideas from fracture mechanics and statistical physics, classical theories, simulation and experimental results to make the statistical physics aspects of fracture more accessible. They explain fracture-like phenomena, highlighting the role of disorder and heterogeneity from a statistical physical viewpoint. The role of defects is discussed in brittle and ductile fracture, ductile to brittle transition, fracture dynamics, failure processes with tension as well as compression: experiments, failure of electrical networks, self-organized critical models of earthquake and their extensions to capture the physics of earthquake dynamics. The text also includes a discussion of dynamical transitions in fracture propagation in theory and experiments, as well as an outline of analytical results in fiber bundle model dynamics With its wide scope, in addition to the statistical physics community, the material here is equally accessible to engineers, earth scientists, mechanical engineers, and material scientists. It also serves as a textbook for graduate students and researchers in physics.

Download or read book Earthquake Early Warning and the Physics of Earthquake Rupture written by Gilead Wurman and published by . This book was released on 2010 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the great debates in seismology today revolves around the question of whether earthquake ruptures are self-similar, cascading failures, or whether their size is somehow predetermined at the start of the rupture. If earthquakes are self-similar there is theoretically no way to determine the magnitude of an event until the rupture has completely terminated, while if it is deterministic the magnitude should be immediately discernible. Recent advances in Earthquake Early Warning methodologies provide new insight into the fundamental physics of earthquake rupture and highlight the importance of understanding the answer to this question. Observations of the amplitude and frequency content of early P-wave arrivals suggest that some information about the final size of an earthquake is already present within a few seconds of the initiation of rupture, in agreement with a host of other observations that show a degree of scaling between large and small earthquakes. While this suggests that earthquakes are deterministic, there is likewise a large body of work, both observational and model-based, that indicates that this is not true and earthquakes are self-similar. This work documents the process of calibrating and testing the ElarmS Earthquake Early Warning methodology in northern California on the Northern California and Berkeley Digital Seismic Networks. In the process the work adds to the body of observations which show a dependency on event magnitude of P-wave frequency content and amplitude. These observations are corroborated with a new set of independent observations of kinematic slip distributions. These new observations indicate that the early slip on a fault also scales with magnitude and suggest again that earthquakes are not entirely self-similar cascading events. In an effort to assign a physical mechanism to the observations of scaling, both in P-waves and in kinematic slip inversions, a hypothetical model is tested wherein the intensity of the early rupture imparts more or less energy to the rupture front and affects the likelihood of the rupture continuing or dying out in the face of unfavorable conditions further along the fault plane. The results of testing this hypothesis are somewhat equivocal, but they are suggestive of the likely truth, that earthquakes exhibit aspects of both deterministic and cascading rupture to some degree. Understanding the details of the interplay between these two aspects is crucial to the successful application of Earthquake Early Warning systems, especially in rare large earthquakes for which there is little empirical data on the performance of these systems.

Download or read book Kinematic Earthquake Source Imaging written by Wenyuan Fan and published by . This book was released on 2017 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: Earthquakes are the primary source of seismic waves in seismology and understanding the earthquake source is essential for predicting ground motions and detailing the physics of rupture. Earthquake kinematic source imaging describes the whole rupture process during an earthquake. It does not directly require the resolved source model to be physically or dynamically plausible, but can help in understanding the conditions of rupture dynamics. Therefore, accurate earthquake source models are highly desirable. In Chapter 2, we develop a frequency-based approach to earthquake slip inversion that requires no prior information on the rupture velocity or slip-rate functions. In Chapter 3, we characterize the rupture process of the 25 April 2015 Nepal earthquake with globally recorded teleseismic P waves. In Chapter 4, we investigate the 10 January 2012 Mw 7.2 Sumatra earthquake in the Wharton basin and detect dynamically-triggered large early aftershocks occurring on or near the subduction interface. In Chapter 5, we constrain the spatiotemporal evolution of the 2009 Tonga-Samoa earthquake with global P-wave back-projection and a multiple moment-tensor inversion. Our results show that the rupture branches east of the trench axis were controlled by the geometry of bending-related faults on the Pacific plate, and that the rupture branch west of the trench axis may correlate with along-strike fore-arc segmentation. In Chapter 6, we detect and locate 48 previously unidentified large early aftershocks triggered by 7

Download or read book Space time Rupture Properties of Large Earthquakes written by Jeffrey Joseph McGuire and published by . This book was released on 2000 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Rupture Characteristics of Large Earthquakes written by and published by . This book was released on 2015 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: The occurrence of many large and/or destructive global earthquakes over the past ten years has provided unprecedented seismic, geodetic, and tsunami recordings that reveal complex rupture processes advancing our understanding of earthquake physics. This thesis research has focused on seismological analysis of recent large earthquakes to extract observational insights that address two fundamental questions, "how do great earthquake rupture?", and "what controls large earthquakes?". We approach these two questions by providing an improved seismological understanding of large earthquake rupture processes, exploring the variation of kinematic source parameters, and placing the ruptures into the context of tectonic plate motions that drive the deformation. Given the great diversity of earthquakes, various seismic tools have been explored to give a better robust characterization of large earthquake ruptures. It includes W-phase point source inversion, back projection of seismic array data to map the space-time distribution of high-frequency coherent seismic radiation, determination of broadband source spectra and radiated energy, waveform inversion for co-seismic finite-source slip distribution, and forward modeling of and joint inversion with tsunami and GPS data. By applying these methods, I have studied large events located in different areas, including 1) megathrusts (subduction zone plate boundaries) along the Japan trench, Middle American Trench, and globally; 2) the large transform fault boundary near Scotia-Sea-Antarctic plate boundary, and 3) intraplate events in subducted slabs near the Philippine trench, at intermediate depth (70-300 km) beneath Rat Island earthquake and in the mantle transition zone (300-700 km) beneath Sea of Okhotsk and Ogasawara Islands. The controlling parameters for earthquake-related hazards (e.g. tsunami and strong ground shaking) and earthquake physical mechanisms (e.g. brittle failure, thermal weakening process, stress transfer) have been investigated with an emphasis on the frequency-dependence seismic radiation.

Download or read book The Rupture Process of Large Earthquakes Along Convergent Margins written by Charles Hershey Estabrook and published by . This book was released on 1992 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Imaging Earthquake Rupture by Waveform Inversion written by Brian P. Cohee and published by . This book was released on 1995 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Physics of Rock Failure and Earthquakes written by Michiyasu Ōnaka and published by . This book was released on 2013 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Physical modelling of earthquake generation processes is essential to further our understanding of seismic hazard. However, the scale-dependent nature of earthquake rupture processes is further complicated by the heterogeneous nature of the crust. Despite significant advances in the understanding of earthquake generation processes, and the derivation of underlying physical laws, controversy remains regarding what the constitutive law for earthquake ruptures ought to be, and how it should be formulated. It is extremely difficult to obtain field data to define physical properties along a fault during a rupture event, at sufficiently high spatial and temporal resolution to resolve the controversy. Instead, laboratory experiments offer a means of obtaining high-resolution measurements that allow the physical nature of shear rupture processes to be deduced. This important new book is written using consistent notation, providing a deeper understanding of earthquake processes from nucleation to their dynamic propagation. Its key focus is a deductive approach based on laboratory-derived physical laws and formulae, such as a unifying constitutive law, a constitutive scaling law, and a physical model of shear rupture nucleation. Topics covered include: the fundamentals of rock failure physics, earthquake generation processes, physical scale dependence, and large-earthquake generation cycles and their seismic activity"--

Download or read book Earthquake and Disaster Risk Decade Retrospective of the Wenchuan Earthquake written by Yong-Gang Li and published by Springer. This book was released on 2019-05-04 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents review papers and research articles focusing on the 2008 Wenchuan earthquake in Sichuan, China, discussing cross-disciplinary and multiple thematic aspects of modern seismological, geophysical, geological and stochastic methodology and technology. Resulting from international and regional earthquake research and disaster mitigation collaborations, and written by international authors from multiple institutions and disciplines, it describes methods and techniques in earthquake science based on investigations of the Wenchuan earthquake. It also includes extensive reference lists to aid further research. The book helps both senior researchers and graduate students in earthquake science to broaden their horizons in data analysis, numerical modeling and structural retrieval for the tectonic, geological, geophysical and mechanical interpretation of the 2008 M8 Wenchuan earthquake to support a global and regional cooperation for preparedness, and the mitigation and management of seismic risk.

Download or read book Joint Analysis of Early Aftershocks Preshocks and Short Period Source Rupture Characteristics of the October 17 1989 Earthquake Including Contribution of Data to a Common Database written by Karen McNally and published by . This book was released on 1991 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: