Download or read book GPS Studies of Crustal Deformation in the Northern Cascadia Subduction Zone written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book GPS Studies of Crustal Deformation in the Northern Cascadia Subduction Zone written by Joseph Alan Henton and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Vancouver Island, located in southwestern coastal British Columbia, overlies the northern portion of the Cascadia Subduction Zone. This region is characterized by extensive seismicity which includes M ∼ 7 crustal earthquakes and less frequent M ∼ 9 megathrust events. Crustal deformation measurements have been carried out in this region since 1978 using various geodetic field techniques: levelling, tide gauge studies, precise gravity, laser ranging, and most recently, GPS. Earlier survey data provided key constraints to elastic slip-dislocation models for estimating the size and location of the rupture area for the next subduction-thrust earthquake. Recent estimates of crustal motions within the North Cascadia Margin based on both campaign GPS network surveys and up to 6.5 years of data from continuous GPS sites are consistent with the strain accumulation expected from a locked subduction fault. The deformation vectors are in the direction of plate convergence within the uncertainty of plate motion models. The observed strain rate across Vancouver Island is, however, smaller (by approximately a factor of 1.5) than the dislocation model prediction, suggesting the presence of visco-elastic effects. Crustal deformation measurements for central Vancouver Island fail to resolve motions that could be associated with the occurrence of large crustal earthquakes, and also suggest that the extent of the seismogenic subduction thrust zone north of the Nootka Fault Zone is extremely limited.

Download or read book Improving Model Constraints for Vertical Deformation Across the Northern Cascadia Margin written by Lisa Wolynec and published by . This book was released on 2004 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Geological Survey of Canada Open File 3938 written by and published by Natural Resources Canada. This book was released on with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book GPS and Seismicity Constraints on the Current Tectonics of the Northern Canadian Cordillera written by Lucinda Jane Leonard and published by . This book was released on 2006 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Studies of Upper Plate Deformation at Subduction Zone Plate Boundaries written by Kirsty Mckenzie and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation I use observations of upper-plate deformation to constrain the kinematics and dynamics of tectonic processes that occur at subduction zones and within plate boundary transition zones. I combine observations that record deformation over weeks to decades (geodetic observations), tens to hundreds of thousands of years (field observations and geochronology), and millions of years (field observations and plate boundary reconstructions), with earthquake cycle modeling. This research is primarily focused on the Cascadia subduction zone, however the results are applicable across many subduction zones globally. Specific related cases that are highlighted include the Hikurangi margin (New Zealand) and the Nankai trough (SW Japan). The studies in my research range from using observations of slow slip earthquakes to constrain the plate motion direction and forces acting down-dip of the seismogenic zone, to observations of permanent upper-plate deformation to better understand the relationship between shallow mechanical locking on the plate interface and upper-plate deformation. Some key findings I present over several chapters are: (1) a model for the Cascadia subduction zone (and other obliquely-convergence subduction zones) that suggests that loading of the locked region at deep levels is down-dip and thus oblique to the loading direction at shallow levels; (2) a new coupling model for the Cascadia subduction zone that relates the variation in GPS velocities (and permanent deformation) from south to north across the margin to the locations of upper-plate strength (geologic terrane) boundaries; and (3) permanent coastal uplift is not being produced continuously, and instead observations from central Cascadia suggest uplift rates can change significantly over ~20 kyrs.

Download or read book Penrose Conference Great Cascadia Earthquake Tricentennial written by and published by . This book was released on 2000 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Seismogenic Zone of Subduction Thrust Faults written by Timothy H. Dixon and published by Columbia University Press. This book was released on 2007-09-20 with total page 691 pages. Available in PDF, EPUB and Kindle. Book excerpt: Subduction zones, one of the three types of plate boundaries, return Earth's surface to its deep interior. Because subduction zones are gently inclined at shallow depths and depress Earth's temperature gradient, they have the largest seismogenic area of any plate boundary. Consequently, subduction zones generate Earth's largest earthquakes and most destructive tsunamis. As tragically demonstrated by the Sumatra earthquake and tsunami of December 2004, these events often impact densely populated coastal areas and cause large numbers of fatalities. While scientists have a general understanding of the seismogenic zone, many critical details remain obscure. This volume attempts to answer such fundamental concerns as why some interplate subduction earthquakes are relatively modest in rupture length (greater than 100 km) while others, such as the great (M greater than 9) 1960 Chile, 1964 Alaska, and 2004 Sumatra events, rupture along 1000 km or more. Contributors also address why certain subduction zones are fully locked, accumulating elastic strain at essentially the full plate convergence rate, while others appear to be only partially coupled or even freely slipping; whether these locking patterns persist through the seismic cycle; and what is the role of sediments and fluids on the incoming plate. Nineteen papers written by experts in a variety of fields review the most current lab, field, and theoretical research on the origins and mechanics of subduction zone earthquakes and suggest further areas of exploration. They consider the composition of incoming plates, laboratory studies concerning sediment evolution during subduction and fault frictional properties, seismic and geodetic studies, and regional scale deformation. The forces behind subduction zone earthquakes are of increasing environmental and societal importance.

Download or read book I Studies in Crustal Deformation Using GPS and Tiltmeters written by Gregory J. Anderson and published by . This book was released on 1999 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Contemporary GPS derived Strain in Northern California written by Jeffrey T. Freymueller and published by . This book was released on 2002 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Continuous GPS Measurements of Crustal Deformation in Southern California written by Jie Zhang and published by . This book was released on 1996 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Interseismic Lithospheric Response of the Southern End of the Cascadia Subduction Zone Since the 1992 Cape Mendocino M 7 1 Earthquake written by Jessica Vermeer and published by . This book was released on 2016 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Cascadia subduction zone (CSZ) in the Pacific Northwest, where the Gorda plate is subducting beneath the North American plate, may be capable of producing M 9 earthquakes. At its southern end, the CSZ terminates at the Mendocino triple junction in northern California, a region of frequent seismic activity. Unique among this seismicity was the 1992 M 7.1 Cape Mendocino earthquake, which caused up to 1.4 m of measured coseismic uplift and may have been a segmented rupture of the southern end of the CSZ. The coseismic deformation was measured using Vertical Extent of Mortality of intertidal organisms, as well as a first order NGS leveling survey. Using static GPS relocation of leveling benchmarks and the position of intertidal organisms I measured vertical crustal deformation over the 23 years since the 1992 event. If this earthquake had occurred on the megathrust interface between the Gorda and North American plates, I expected to see 10-20 cm of subsidence near the peak of coseismic uplift. However, this earthquake could have occurred along a subsidiary fault within the accretionary wedge or upper plate, in which case the deformation rate should be much lower. Benchmark relocation and intertidal organism relocation yield maximum vertical deformation of 1 mm/yr. These low interseismic deformation rates measurements indicate that the 1992 M 7.1 Cape Mendocino earthquake was not rupture of the subduction zone interface, but likely occurred within the upper plate accretionary complex on a subsidiary fault.

Download or read book Geological Survey of Canada Current Research Online no 2000 A22 written by and published by Natural Resources Canada. This book was released on with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Encyclopedia of Solid Earth Geophysics written by Harsh Gupta and published by Springer Science & Business Media. This book was released on 2011-06-29 with total page 1579 pages. Available in PDF, EPUB and Kindle. Book excerpt: The past few decades have witnessed the growth of the Earth Sciences in the pursuit of knowledge and understanding of the planet that we live on. This development addresses the challenging endeavor to enrich human lives with the bounties of Nature as well as to preserve the planet for the generations to come. Solid Earth Geophysics aspires to define and quantify the internal structure and processes of the Earth in terms of the principles of physics and forms the intrinsic framework, which other allied disciplines utilize for more specific investigations. The first edition of the Encyclopedia of Solid Earth Geophysics was published in 1989 by Van Nostrand Reinhold publishing company. More than two decades later, this new volume, edited by Prof. Harsh K. Gupta, represents a thoroughly revised and expanded reference work. It brings together more than 200 articles covering established and new concepts of Geophysics across the various sub-disciplines such as Gravity, Geodesy, Geomagnetism, Seismology, Seismics, Deep Earth Processes, Plate Tectonics, Thermal Domains, Computational Methods, etc. in a systematic and consistent format and standard. It is an authoritative and current reference source with extraordinary width of scope. It draws its unique strength from the expert contributions of editors and authors across the globe. It is designed to serve as a valuable and cherished source of information for current and future generations of professionals.

Download or read book Crustal Deformation Along the San Andreas Fault and Within the Tibetan Plateau Measured Using GPS written by Qizhi Chen and published by . This book was released on 2002 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Using the Global Positioning System (GPS), we study crustal deformation along the San Andreas Fault (SAF) in the San Francisco Bay area and within the Tibetan Plateau, and provide new constraints for the kinematics of these actively deforming plate boundaries. GPS measurements in 1996 and 1997 and Electronic Distance Measuring (EDM) data from the 1970s and 1980s at sites along the SAF in northern California were used to determine the near-fault strain rate and to investigate the slip rate, locking depth, and rheology. We found a pronounced high near-fault shear strain rate that can be explained by a 2-D inhomogeneous model in which a low-rigidity compliant zone concentrates strain near the fault. We suggest that the materials on either side of the fault and the cumulative fault offset play a role in the development of the compliant zone. If such a compliant zone is present but unmodeled, the geodetic estimates of slip rate and locking depth (seismogenic depth) would be biased. This would lead to a miscalculated seismic hazard. Thirteen GPS sites in southern Tibet, surveyed in 1995, 1998 and 2000, were merged with other data from China and Nepal into a single, self-consistent velocity field. The himalaya and southern Tibet was modeled using a kinematically-consistent block model and elastic dislocation theory. We show a significantly lower convergence rate between India and Eurasia in central Himalaya than that previously estimated. We observe that southern Tibet undergoes non-uniform (spatial) east-west extension with one-half of the extension across the Yadong-Gulu rift. We infer that spatially non-uniform extension in southern Tibet results in variation of the arc-normal convergence rates along the Himalaya, and that the Yarlung-Zangbo suture or adjacent structure may be active as a right-lateral strike slip fault. From 44 GPS sites in the Tibetan Plaeau, we show that deformation of Tibet is distributed and strain accumulation is spatially uniform across the entire plateau. We propose a kinematic model for the Tibetan Plateau to be a combination of rigid block motion, pure shear and uniaxial contraction in the direction of about N32E̊, comparable to the convergence direction between India and Eurasia"--Leaf 3).

Download or read book Enhanced Surface Imaging of Crustal Deformation written by A. John Haines and published by Springer. This book was released on 2015-08-11 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book takes an in depth look at a novel methodology for analyzing Global Positioning System (GPS) data to obtain the highest possible resolution surface imaging of tectonic deformation sources without prescribing the nature of either the sources or the subsurface medium. GPS methods are widely used to track the surface expression of crustal deformation at tectonic plate boundaries, and are typically expressed in terms of velocity fields or strain rate fields. Vertical derivatives of horizontal stress (VDoHS) rates at the Earth’s surface can also be derived from GPS velocities, and VDoHS rates provide much higher resolution information about subsurface deformation sources than velocities or strain rates. In particular, VDoHS rates allow for high precision estimates of fault dips, slip rates and locking depths, as well as objective characterization of previously unknown (or hidden) tectonic deformation zones.

Download or read book GPS Trends in Precise Terrestrial Airborne and Spaceborne Applications written by Gerhard Beutler and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 345 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings include most of the papers presented at the lAG Sympo sium GPS Trends in Precise Terrestrial, Airborne, and Spacebome Appli cations held in July 1995 during the XXI-th IUGG General Assembly in Boulder, Colorado. The symposium was jointly organized by the lAG and the International Union of Surveys and Mapping (IUSM). The symposium was divided into four sessions, namely (1) The International GPS Service for Geodynamics (IGS) and other Permanent Networks, (2) Spaceborne Applications of the GPS, (3) Kinematic Applications of the GPS, and (4) The GPS and its Relations to Geophysics. The main purpose was to give an overview of the state of the art in 1995 of the applications of the GPS to geodynamics, geodesy, surveying, and navi gation. The call for papers generated a flood of originally more than 70 abstracts; quite a few could be redirected to other symposia, but still 56 papers found their way into these proceedings. We thus conclude that the volume gives a rather complete overview of GPS Trends in Precise Terrestrial, Airborne, and Spacebome Applications in the year 1995.