Download or read book Seismic Behavior on Oceanic Transform Faults Revealed by Numerical Modeling and Seismic Observation written by Pengcheng Shi and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Earthquake Behavior and Structure of Oceanic Transform Faults written by Emily Carlson Roland and published by . This book was released on 2012 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: Oceanic transform faults that accommodate strain at mid-ocean ridge offsets represent a unique environment for studying fault mechanics. Here, I use seismic observations and models to explore how fault structure affects mechanisms of slip at oceanic transforms. Using teleseismic data, I find that seismic swarms on East Pacific Rise (EPR) transforms exhibit characteristics consistent with the rupture propagation velocity of shallow aseismic creep transients. I also develop new thermal models for the ridge-transform fault environment to estimate the spatial distribution of earthquakes at transforms. Assuming a temperature-dependent rheology, thermal models indicated that a significant amount of slip within the predicted temperature-dependent seismogenic area occurs without producing large-magnitude earthquakes. Using a set of local seismic observations, I consider how along-fault variation in the mechanical behavior may be linked to material properties and fault structure. I use wide-angle refraction data from the Gofar and Quebrada faults on the equatorial EPR to determine the seismic velocity structure, and image wide low-velocity zones at both faults. Evidence for fractured fault zone rocks throughout the crust suggests that unique friction characteristics may influence earthquake behavior. Together, earthquake observations and fault structure provide new information about the controls on fault slip at oceanic transform faults.
Download or read book The Dynamics of Ocean Transform Faults written by Patricia Michelle Marie Gregg and published by . This book was released on 2008 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: Segmentation and crustal accretion at oceanic transform fault systems are investigated through a combination of geophysical data analysis and geodynamical and geochemical modeling. Chapter 1 examines the effect of fault segmentation on the maximum predicted earthquake magnitude of an oceanic transform fault system. Results of thermal modeling suggest that fault segmentation by intra-transform spreading centers (ITSC) drastically reduces the available brittle area of a transform fault and thus limits the available earthquake rupture area. Coulomb stress models suggest that long ITSCs will prohibit static stress interaction between segments of a transform system and further limit the maximum possible magnitude of a given transform fault earthquake. In Chapter 2, gravity anomalies from a global set of oceanic transform fault systems are investigated. Surprisingly, negative residual mantle Bouguer gravity anomalies are found within fastslipping transform fault domains. These gravity observations suggest a mass deficit within fast-slipping transform faults, which may result from porosity variations, mantle serpentinization, and/or crustal thickness variations. Two-dimensional forward modeling and the correlation of the negative gravity anomalies to bathymetric highs indicate crustal thickness excesses in these locations. Finally, in Chapter 3, mantle thermal and melting models for a visco-plastic rheology are developed to investigate the process of mantle melting and crustal accretion at ITSCs within segmented transform faults, and are applied to the Siqueiros transform fault system. Models in which melt migrates into the transform fault domain from a large region of the mantle best explain the gravity-derived crustal thickness variations observed at the Siqueiros transform. Furthermore, a mantle potential temperature of 1350°C and fractional crystallization at depths of 9 - 15.5 km best explain the major element composition variation observed at the Siqueiros transform.
Download or read book Seismicity and Structure of the Orozco Transform Fault from Ocean Bottom Seismic Observation Anne Martine Tr hu written by Anne Martine Tréhu and published by . This book was released on 1982* with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Dynamics of Oceanic Transform Faults written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: National Science Foundation Graduate Research Fellowship, Hollister Graduate Research Fellowship, WHOI Academic Programs Office - Research Fellowship.
Download or read book Living on an Active Earth written by National Research Council and published by National Academies Press. This book was released on 2003-09-22 with total page 431 pages. Available in PDF, EPUB and Kindle. Book excerpt: The destructive force of earthquakes has stimulated human inquiry since ancient times, yet the scientific study of earthquakes is a surprisingly recent endeavor. Instrumental recordings of earthquakes were not made until the second half of the 19th century, and the primary mechanism for generating seismic waves was not identified until the beginning of the 20th century. From this recent start, a range of laboratory, field, and theoretical investigations have developed into a vigorous new discipline: the science of earthquakes. As a basic science, it provides a comprehensive understanding of earthquake behavior and related phenomena in the Earth and other terrestrial planets. As an applied science, it provides a knowledge base of great practical value for a global society whose infrastructure is built on the Earth's active crust. This book describes the growth and origins of earthquake science and identifies research and data collection efforts that will strengthen the scientific and social contributions of this exciting new discipline.
Download or read book Transform Plate Boundaries and Fracture Zones written by Joao C. Duarte and published by Elsevier. This book was released on 2018-09-25 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transform Plate Boundaries and Fracture Zones bridges the gap between the classic plate tectonic theory and new emerging ideas, offering an assessment of the state-of-the-art, pending questions, and future directions in the study of transform plate boundaries and fracture zones. The book includes a number of case studies and reviews on both oceanic and continental tectonic settings. Transform Plate Boundaries and Fracture Zones is a timely reference for a variety of researchers, including geophysicists, seismologists, structural geologists and tectonicists, as well as specialists in exploration geophysics and natural hazards. This book can also be used as an up-to-date reference at universities in both undergraduate and postgraduate levels. Reviews ideas and concepts about transform plate boundaries and fracture zones Includes a variety of case studies on both oceanic and continental settings Addresses innovative and provocative ideas about the activity of fracture zones and transform faults and their impacts to the human society
Download or read book Deformation and Seismic Style of Oceanic Transform Faults written by Sophie Cox and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Acoustic Monitoring of Earthquakes Along the Blanco Transform Fault Zone and Gorda Plate and Their Tectonic Implications written by Robert P. Dziak and published by . This book was released on 1997 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydroacoustic tertiary (T- ) waves are seismically generated acoustic waves that propagate over great distances in the ocean sound channel with little loss in signal strength. Hydrophone recorded T-waves can provide a lower earthquake detection threshold and an improved epicenter location accuracy for oceanic earthquakes than land-based seismic networks. Thus detection and location of NE Pacific ocean earthquakes along the Blanco Transform Fault (BTFZ) and Gorda plate using the U.S. Navy's SOSUS (SOund SUrveillance System) hydrophone arrays afford greater insight into the current state of stress and crustal deformation mechanics than previously available. Acoustic earthquake information combined with bathymetry, submersible observations, earthquake source-parameter estimates, petrologic samples, and water-column chemistry renders a new tectonic view of the southern Juan de Fuca plate boundaries. Chapter 2 discusses development of seismo-acoustic analysis techniques using the well-documented April 1992 Cape Mendocino earthquake sequence. Findings include a hydrophone detection threshold estimate (M~2.4), and T-wave propagation path modeling to approximate earthquake acoustic source energy. Empirical analyses indicate that acoustic energy provides a reasonable magnitude and seismic moment estimate of oceanic earthquakes not detected by seismic networks. Chapters 3 documents a probable volcanogenic T-wave event swarm along a pull-apart basin within the western BTFZ during January 1994. Response efforts yielded evidence of anomalous water-column 3He concentrations, pillow-lava volcanism, and the first discovery of active hydrothermal vents along an oceanic fracture zone. Chapter 4 discusses the detection of a NE-SW trending microearthquake band along the mid-Gorda plate which was active from initiation of SOSUS recording in August 1991 through July 1992, then abruptly ceased. It is proposed that eventual termination of the Gorda plate seismicity band is due to strain reduction associated with the Cape Mendocino earthquake sequence. Chapter 5 combines bathymetric, hydro-acoustic, seismic, submersible, and gravity data to investigate the active tectonics of the transform parallel Blanco Ridge (BR), along the eastern BTFZ. The BR formation mechanism preferred here is uplift through strike-slip motion (with a normal component) followed by formation and intrusion of mantle-derived serpentinized-peridotite into the shallow ocean crust. The conclusion considers a potential link between the deformation patterns observed along the BTFZ and Gorda plate regions.
Download or read book Transform Faults and Lithospheric Structure written by Christopher S. Takeuchi and published by . This book was released on 2012 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, I study the influence of transform faults on the structure and deformation of the lithosphere, using shipboard and geodetic observations as well as numerical experiments. I use marine topography, gravity, and magnetics to examine the effects of the large age-offset Andrew Bain transform fault on accretionary processes within two adjacent segments of the Southwest Indian Ridge. I infer from morphology, high gravity, and low magnetization that the extremely cold and thick lithosphere associated with the Andrew Bain strongly suppresses melt production and crustal emplacement to the west of the transform fault. These effects are counteracted by enhanced temperature and melt production near the Marion Hotspot, east of the transform fault. I use numerical models to study the development of lithospheric shear zones underneath continental transform faults (e.g. the San Andreas Fault in California), with a particular focus on thermomechanical coupling and shear heating produced by long-term fault slip. I find that these processes may give rise to long-lived localized shear zones, and that such shear zones may in part control the magnitude of stress in the lithosphere. Localized ductile shear participates in both interseismic loading and postseismic relaxation, and predictions of models including shear zones are within observational constraints provided by geodetic and surface heat flow data. I numerically investigate the effects of shear zones on three-dimensional postseismic deformation. I conclude that the presence of a thermally-activated shear zone minimally impacts postseismic deformation, and that thermomechanical coupling alone is unable to generate sufficient localization for postseismic relaxation within a ductile shear zone to kinematically resemble that by aseismic fault creep (afterslip). I find that the current record geodetic observations of postseismic deformation do not provide robust discriminating power between candidate linear and power-law rheologies for the sub-Mojave Desert mantle, but longer observations may potentially allow such discrimination.
Download or read book Dead Sea Transform Fault System Reviews written by Zvi Garfunkel and published by Springer. This book was released on 2014-07-03 with total page 365 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Dead Sea transform is an active plate boundary connecting the Red Sea seafloor spreading system to the Arabian-Eurasian continental collision zone. Its geology and geophysics provide a natural laboratory for investigation of the surficial, crustal and mantle processes occurring along transtensional and transpressional transform fault domains on a lithospheric scale and related to continental breakup. There have been many detailed and disciplinary studies of the Dead Sea transform fault zone during the last 20 years and this book brings them together. This book is an updated comprehensive coverage of the knowledge, based on recent studies of the tectonics, structure, geophysics, volcanism, active tectonics, sedimentology and paleo and modern climate of the Dead Sea transform fault zone. It puts together all this new information and knowledge in a coherent fashion.
Download or read book Seismicity and Structure of the Orozco Transform Fault from Ocean Bottom Seismic Observations written by and published by . This book was released on 1982 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Seismicity and Structure of the Orozco Transform Fault from Ocean Bottom Seismic Observations written by Anne Martine Tréhu and published by . This book was released on 1982 with total page 371 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seismic waves generated by sources ranging from 2.7 kg shots of TNT to magnitude 5 earthquakes were studied in order to determine the seismic activity and crystal structure of the Orozco transform fault. Most of the data were collected by a network of 29 ocean bottom seismometers (OBS) and hydrophones (OBH) which were deployed as part of a project ROSE (Rivera Ocean Seismic Experiment). Additional information was provided by magnetic anomaly and bathymetric data collected during and prior to ROSE and by teleseismic earthquakes recorded by the WWSSN (Worldwide Seismic Station Network). (Author).
Download or read book Geocomplexity and the Physics of Earthquakes written by John Rundle and published by American Geophysical Union. This book was released on 2000-01-10 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 120. Earthquakes in urban centers are capable of causing enormous damage. The January 16, 1995 Kobe, Japan earthquake was only a magnitude 6.9 event and yet produced an estimated $200 billion loss. Despite an active earthquake prediction program in Japan, this event was a complete surprise. Similar scenarios are possible in Los Angeles, San Francisco, Seattle, and other urban centers around the Pacific plate boundary. The development of forecast or prediction methodologies for these great damaging earthquakes has been complicated by the fact that the largest events repeat at irregular intervals of hundreds to thousands of years, resulting in a limited historical record that has frustrated phenomenological studies. The papers in this book describe an emerging alternative approach, which is based on a new understanding of earthquake physics arising from the construction and analysis of numerical simulations. With these numerical simulations, earthquake physics now can be investigated in numerical laboratories. Simulation data from numerical experiments can be used to develop theoretical understanding that can be subsequently applied to observed data. These methods have been enabled by the information technology revolution, in which fundamental advances in computing and communications are placing vast computational resources at our disposal.
Download or read book Strain Release Along Oceanic Transform Faults written by Lisa Maureen Stewart and published by . This book was released on 1983 with total page 275 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Understanding Fault Evolution Using Numerical Models and Seismic Data Observations written by Sophie Wen-Jiao Pan and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Seismic and Numerical Constraints on the Formation and Evolution of Ocean Lithosphere written by Hannah F. Mark and published by . This book was released on 2019 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis explicates aspects of the basic structure of oceanic lithosphere that are shaped by the processes that form the lithosphere. The strength of lithospheric plates relative to the underlying mantle enables the surface plate motions and plate boundary processes that characterize plate tectonics on Earth. Surprisingly, we have a relatively poor understanding of the physical mechanisms that make the lithosphere strong relative to the asthenosphere, and we lack a reference model for ordinary lithospheric structure that can serve as a baseline for comparing geophysical observations across locations. Chapters 2 and 3 of this thesis investigate the seismic structure of a portion of the Pacific plate where the simple tectonic history of the plate suggests that its structure can be used as a reference model for oceanic lithosphere. We present measurements of shallow azimuthal seismic anisotropy, and of a seismic discontinuity in the upper mantle, that reflect the effects of shear deformation and melting processes involved in the formation of the lithosphere at mid-ocean ridges. Chapter 4 uses numerical models to explore factors controlling fault slip behavior on normal faults that accommodate tectonic extension during plate formation.
