Download or read book Seismotectonics of the Himalayas and the Tibetan Plateau written by Jan R. Baur and published by . This book was released on 2007 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a detailed seismotectonic investigation of the Himalayan region and the Tibetan plateau as part of project HiCLIMB to explore the state of stress and the kinematics of the world?s largest continental collision zone. Using full regional waveforms for moment tensor inversion, source parameters for 107 earthquakes were determined with moment-magnitudes (Mw) ranging from 3.5 to 6.3. The significant decrease in magnitude threshold with respect to previous studies was accomplished through the usage of broadband data from the HiCLIMB, HIMNT, and Bhutan temporary networks. Combining the results from this study with previously published earthquake source parameters, the investigation focuses on three topics: (1) Deformation along the front of the Himalayan arc associated with the Main Himalayan Thrust (2) Extension in the southern Tibetan plateau, and (3) Location and stress orientation of intermediate-depth earthquakes. Thrust event epicenters along the Himalayan front closely coincide with the 3500 m topography contour. These earthquakes can be associated with elastic strain accumulation near the lower tip of the locked part of the MHT due to tectonic loading from its creeping down-dip extension. Centroid depths and nodal plane dips of these thrust events are inconsistent with slip merely on the main detachment and indicate significant deformation in the vicinity of the MHT. Especially in far western Nepal, nodal plane dips are systematically steeper and slip during these events might play a role in the formation of asperities and barriers on the detachment surface. The P-axes azimuths of the thrust events along the Himalayan arc deviate considerably from a mere circular geometry. Spatial filtering of the regional topography reveals that slip of events in the footwall as well as the hanging wall aligns perpendicular to the mountain range on a 50 km wavelength scale. The topography-perpendicular alignment of the slip direction on planes with significant inclination suggests that these thrust events contribute considerably to the mountain building process and to the formation of the local shape of the arc. Deformation on the southern Tibetan plateau is dominated by shallow normal faulting in the upper 15 km of the crust. The extensional direction, while generally trending east-west, shows an apparent transition from arc parallel in the Tethyan Himalaya to northward convex in the southern Lhasa terrane. North of about N31ð, deformation changes to strike-slip prevalence. The locations of changes in faulting patterns coincide with changes in geometry of the underthrusting Indian crust revealed by receiver function images. This correlation indicates a significant influence of basal traction on shallow crustal faulting processes. This study provides additional evidence that most intermediate-depth seismicity occurs beneath the Moho, signifying a strong upper mantle. Faulting in the upper mantle is dominated by strike-slip faulting with northerly trending P-axes. The maximum horizontal compressive stress axes of mantle earthquakes align with the direction of the India-Eurasia convergence and imply a relation of this deformation to the subduction process.
Download or read book Seismicity and Active Tectonics of the Himalayas and Tibetan Plateau written by James Fu Ni and published by . This book was released on 1984 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Seismic Reflection and Tectonic Studies of the Central Himalayas Southern Tibet written by Michael Lee Hauck and published by . This book was released on 1997 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Colliding Continents written by M. P. Searle and published by Oxford University Press, USA. This book was released on 2013-03-28 with total page 463 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gargantuan geological forces created the spectacular mountain ranges of the Himalaya and Karakoram. Mike Searle, one of the world's most experienced field geologists, tells the scientific story, illustrating it with his own photographs, and accounts of his mountaineering and research in the region.
Download or read book Seismic Wave Attenuation of the Crust and Upper Mantle in the Himalaya and South Central Tibetan Plateau written by Patrick W. Monigle and published by . This book was released on 2014 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent geophysical and geological investigations of the Tibetan plateau have given rise to conflicting models of plateau growth and deformation, where the presence and extent of partial melt in the crust could be a determining factor. Here we investigate the attenuation structure of the crust and upper mantle, as attenuation is particularly sensitive to temperature and fluids, both aqueous and melts. We present 3D Qp and Qs results of attenuation structure beneath the HiCLIMB array using local earthquakes recorded between 2004 July and 2005 August. Additional synthetic data analysis shows our ability to expand attenuation analysis beyond the traditional use of first-arriving seismic phases to include reflected and refracted arrivals from the Moho and a persistent upper crust velocity interface. Synthetic analysis also reveals a bandwidth-limited window over which source and attenuation can be uniquely determined, improving the precision of attenuation measurements. Results indicate a high Qp, s upper crust, interrupted by moderate to low Qp faulting and evidence for partial fluid saturation to depths of 15 km and full saturation before 30 km depth. Middle and lower crust attenuation is broadly low Qp, s, with evidence for limited partial melt and interrupted by high Qp, s bodies near the termination of the subducting Indian plate and coincident with a sharp decrease in upper mantle Qp. We find little evidence for extensive partial melt in the crust and the sharpness of Q transitions at depth coincident with changes in faulting style in the upper crust suggest strike-slip motion penetrates the crust and upper mantle at the terminus of subduction.
Download or read book Himalaya Dynamics of a Giant Current Activity of the Himalayan Range written by Rodolphe Cattin and published by John Wiley & Sons. This book was released on 2023-07-21 with total page 325 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Himalaya is well known as the largest and highest mountain belt on Earth. Advances in geoscience over the past few decades have revealed a complex picture of the dynamics of this giant, opening up questions about the initial stages of Himalayan building, lateral variations in its structures, variations in tectonic forcing, tectonic-climate coupling and assessments of the natural hazards affecting this area. In this three-volume book, we present the current knowledge on the building and present-day behavior of the Himalayan range. The objective is not to be exhaustive, but to provide some key elements used by researchers to unravel the many processes acting in the Himalayan dynamics. Mountain environments are at the forefront of climate change with glacier retreat, landslides, flash floods and water availability. Understanding the delicate balance that controls the dynamics of the Himalayan giant is now, more than ever, a major challenge for the scientific community.
Download or read book Microearthquake Seismology and Seismotectonics of South Asia written by J.R. Kayal and published by Springer Science & Business Media. This book was released on 2008-08-22 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is the outcome of about 30 years of research in the field of earthquake seismology in various parts of South Asia. It comprehensively deals with topics raning from plate tectonics to seismic waves in general. State-of-the-art techniques in earthquake location/relocation, fault plane solution, waveform inversion, seismic tomography, fractals etc. are discussed, and the results are interpreted in terms of seismic source processes in the region.
Download or read book Tectonic Evolution of the Himalayas and Tibet written by Royal Society (Great Britain). Discussion Meeting and published by . This book was released on 1988 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Late Quaternary Seismicity and Climate in the Western Nepal written by Zakaria Ghazoui and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Himalayan collision, in which India underthrusts below Tibet, regularly produces major destructive earthquakes in Nepal and its neighboring countries, most of which are fatal to nearby communities. As a wall dividing the Indian plains and the Tibetan plateau, the Himalaya also significantly modifies the atmospheric circulation, affecting both the local and global climate. This thesis explores the poorly known Quaternary history and evolution of Himalayan climate and seismicity, more particularly in the least populated and most remote region of Western Nepal. In terms of climate and environmental change, one of the least understood aspects of Himalayan history during the late Quaternary is the extension of glaciers and their impacts on landscape evolution. Based on field observations, cosmogenic nuclide dating (10Be) and satellite observations, we estimated the maximum extent of glaciers during the Last Glacial Maximum, which supports the hypothesis of a relatively large glacier cover, but not of an extended ice cap, at the scale of Western Nepal. In terms of seismology, the social, economic and political implications of the occurrence of an earthquake of higher magnitude than the recent earthquake of 2015, whose epicenter is located near the city of Gorkha, is a major concern and largely motivates this thesis. The last major earthquake of magnitude greater than 8 (Mb) took place on 6 June 1505 and had a profound impact on the Nepalese population and the surrounding area. In Western Nepal the 1505 event was the last earthquake that ruptured the Main Frontal Thrust according to historical archives and paleoseismological studies, which gave rise to the concept of a seismic gap in western Nepal and adjacent areas in northern India. With this in mind, this thesis addresses two major issues on the Himalayan seismic behavior: on the first hand is the hypothesis of a seismic gap in the central Himalaya and on the second the temporal distribution of earthquakes during the late Quaternary. For this purpose, a new research approach independent of paleoseismic trenches was applied in the Himalaya. By using lakes as paleoseismometers, we were able to refine the temporal resolution and identify earthquakes that had not yet been documented in the accessible databases on a 700-year scale. Our results from Lake Rara highlight significant previously-unknown earthquakes (Mw>6.5) and they reveal that Western Nepal is seismically as active as central Nepal. Furthermore, they call into question the hypothesis of a seismic gap in the central Himalaya. Based on a longer sediment core from the same lake, we studied the temporal distribution of earthquakes over a period of 6000 years, which has highlighted the random nature of the occurrence of earthquakes, constituting a paradigm shift where the notion of seismic cycle is still prevalent. The random nature of the occurrence of earthquakes both on short (instrumental) and Quaternary time scales disproves the hypothesis of the seismic gap in the central Himalaya and underlines the permanent risk for the million people of concern. The final part of this thesis addresses the possible global relationship between seismic rate fluctuations and climate change during the Holocene. Our results show that the global seismicity clustered over 7000 years and appears to be synchronous with the sum of glacial advances through the Mid and Late Holocene.
Download or read book Evolution of the Himalaya Based on Seismotectonics and Deep Seismic Soundings written by K. L. Kaila and published by . This book was released on 1976 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Himalayan Tectonics written by P.J. Treloar and published by Geological Society of London. This book was released on 2019-10-08 with total page 674 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Himalaya–Karakoram–Tibet mountain belt resulted from Cenozoic collision of India and Asia and is frequently used as the type example of a continental collision orogenic belt. The last quarter of a century has seen the publication of a remarkably detailed dataset relevant to the evolution of this belt. Detailed fieldwork backed up by state-of-the-art structural analysis, geochemistry, mineral chemistry, igneous and metamorphic petrology, isotope chemistry, sedimentology and geophysics produced a wide-ranging archive of data-rich scientific papers. The rationale for this book is to provide a coherent overview of these datasets in addressing the evolution of the mountain ranges we see today. This volume comprises 21 specially invited review papers on the Himalaya, Kohistan arc, Tibet, the Karakoram and Pamir ranges. These papers span the history of Himalayan research, chronology of the collision, stratigraphy, magmatic and metamorphic processes, structural geology and tectonics, seismicity, geophysics, and the evolution of the Indian monsoon. This landmark set of papers should underpin the next 25 years of Himalayan research.
Download or read book Growth and Collapse of the Tibetan Plateau written by Richard Gloaguen and published by Geological Society of London. This book was released on 2011 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite agreement on first-order features and mechanisms, critical aspects of the origin and evolution of the Tibetan Plateau, such as the exact timing and nature of collision, the initiation of plateau uplift, and the evolution of its height and width, are disputed, untested or unknown. This book gathers papers dealing with the growth and collapse of the Tibetan Plateau. The timing, the underlying mechanisms, their interactions and the induced surface shaping, contributing to the Tibetan Plateau evolution are tightly linked via coupled and feedback processes. We present interdisciplinary contributions allowing insight into the complex interactions between lithospheric dynamics, topography building, erosion, hydrological processes and atmospheric coupling. The book is structured in four parts: early processes in the plateau formation; recent growth of the Tibetan Plateau; mechanisms of plateau growth; and plateau uplift, surface processes and the monsoon.
Download or read book Zagros Hindu Kush Himalaya written by F. M. Delany and published by American Geophysical Union. This book was released on 1981 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Published by the American Geophysical Union as part of the Geodynamics Series, Volume 3. The International Geodynamics Project focussed attention on processes within the earth responsible for the movement of the lithospheric blocks. At anyone time, strong tectonic activity appears limited to a few mobile belts. Most of the present-day seismic activity is confined to the Circum-Pacific belt, the Alpide belt and the mid-oceanic ridges. These belts include oceanic and continental rift systems, the island arcs and young folded mountains. Continent to continent collision of the Eurasian and the Indian plates is generally believed to be responsible for the origin of the Himalaya, the tectonics of this region and the neighbouring south and central Asia. To focus attention on geodynamic problems in this relatively much less known Alpine-Himalayan region bounded by Iran in the West and Burma in the East, the Inter-Union Commission on Geodynamics formed a separate Working Group 3b under the Chairmanship of Hari Narain. Later, in 1975, this Working Group 3b on "Geodynamics of the Alpine-Himalayan region, East" was given independant status and re-numbered as Working Group 6.
Download or read book Geology of the Himalayas Papers on geophysics written by Guangcen Li and published by . This book was released on 1990 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geology of the Himalayas Papers on geology written by Guangcen Li and published by . This book was released on 1990 with total page 562 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structural and Thermal Evolution of the Himalayan Thrust Belt in Midwestern Nepal written by P.G. DeCelles and published by Geological Society of America. This book was released on 2020-06-16 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Spanning eight kilometers of topographic relief, the Himalayan fold-thrust belt in Nepal has accommodated more than 700 km of Cenozoic convergence between the Indian subcontinent and Asia. Rapid tectonic shortening and erosion in a monsoonal climate have exhumed greenschist to upper amphibolite facies rocks along with unmetamorphosed rocks, including a 5-6-km-thick Cenozoic foreland basin sequence. This Special Paper presents new geochronology, multisystem thermochronology, structural geology, and geological mapping of an approximately 37,000 km2 region in midwestern and western Nepal. This work informs enduring Himalayan debates, including how and where to map the Main Central thrust, the geometry of the seismically active basal Himalayan detachment, processes of tectonic shortening in the context of postcollisional India-Asia convergence, and long-term geodynamics of the orogenic wedge"--Publisher's website
Download or read book Principles of Seismology written by Agustín Udías Vallina and published by Cambridge University Press. This book was released on 2018 with total page 573 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new edition features a completely new chapter on digital seismic data processing, numerous examples and 100 problems.
