Download or read book Quaternary Slip History and Structural Analysis of the Morongo Valley Fault Morongo Valley CA written by James McNeil and published by . This book was released on 2018 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Morongo Valley Fault (MVF) is a northeast trending 18 km-long fault that is a splay from the overall sinistral Pinto Mountain Fault (PMF) system, located along Hwy 62 between Coachella Valley to the south and Yucca Valley to the north. Project results seek to constrain the role of the MVF with respect to the Coachella Valley SAF and Eastern California Shear Zone systems, and the hazard that rupture of this system poses to southern California residents. Mapping of the MVF reveals a series of en-echelon right step overs that resemble a sinistral extensional duplex. Uplifted terrace remnants of Quaternary alluvium occur to the SE of the fault, which dips northwest and is interpreted to be a left-oblique, normal fault system. A trench excavated across the MVF exposes strong evidence for one event at the bottom of the trench overlain by a colluvial wedge, and weak evidence for a second event at the top of the wedge. Calibrated radiocarbon ages from detrital charcoal constrain the first and possible second event to between 2,200-12,850 yrs BP. Three IRSL samples from the trench give much older ages (~20,000-116,000 yrs BP). The IRSL ages are not considered viable ages and probably carry an inheritance signal related to incomplete bleaching of feldspar grains. The trench site’s record of one, and possibly two, events since latest Pleistocene time suggests that the MVF ruptures infrequently relative to the Coachella Valley SAF system (average recurrence interval = ~220 yrs), and eastern PMF (at least four Holocene events). It is possible that the events on the MVF correlate with 1-2 events on eastern PMF. Alternatively, it is equally possible that the MVF breaks independently. The Eastern California Shear Zone (ECSZ) and 1992 Landers earthquake sequence may form the boundary between the eastern PMF, and MVF/western PMF. The paleoseismic record of the western PMF is unknown, but its geomorphic expression is similar to the MVF, and leads to speculation that the two faults possibly share a similar history. It seems likely, therefore that the MVF/western PMF act independently in the region. One explanation is that the SAF, PMF-MVF, and ECSZ form a triangle-shaped structural block at the southern Big Bend region of the SAF that acts as some form of crustal-scale 'ball-bearing' or pivot that accommodates slip transfer and gradients at the intersection of the SAF system and ECSZ. By itself, the MVF probably poses little seismic hazard to the region, but its location in the center of this complex region could mean that it breaks during or associated with rare events that involve multiple fault systems.

Download or read book Late Pleistocene Slip Rate for the Western Pinto Mountain Fault Morongo Valley Southern California written by Katherine Gabriel and published by . This book was released on 2017 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt: The San Gorgonio Pass (SGP) region of the San Andreas fault (SAF) system in southern California is complicated by overlapping, active strands and its intersection with prominent, secondary structures such as the Pinto Mountain fault (PMF). Recent work in this area proposes that strain may be transferred from the Mission Creek strand of the SAF to the Eastern California Shear Zone (ECSZ), at least partly via the PMF. Like the better known Garlock fault, the PMF is a major east-west trending left-lateral transverse fault that intersects the Mission Creek strand of the SAF in the eastern SGP area. Geodetic and geologic slip rates reported for the PMF vary from 1 to 12.5 mm/yr and are poorly constrained because of a lack of geologic data. This report describes a geologic slip rate from faulted alluvium in Big Morongo Canyon in Morongo Valley, California. A best-constrained strath contact between late Pleistocene alluvium (Qoa) and underlying bedrock (ggm) is offset in a left-lateral sense a total of 228 – 303 m. I obtained cosmogenic 10Be exposure ages of six monzo-granite boulders on the surface of Qoa. Assuming zero-erosion rate, boulder ages range from ~63 ka to ~88 ka. I believe that surface deflation and erosion has occurred, and therefore choose a weighted average of 86.9 +/- 4.5 ka as the preferred age for the surface of Qoa. I calculate a preferred slip rate of 3.0 +0.6/-0.4 mm/yr for western PMF system for the last ~87 ka. A fault scarp on one of the secondary splays in latest Pleistocene to Holocene alluvium (Qa) indicates that the western PMF has been active during the last

Download or read book Quaternary Slip History of the Eureka Valley Fault Northern Segment of the Eastern California Shear Zone written by Jordan D. Burkey 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 Late Quaternary Slip Histories and Geochronology Within the Southern San Andreas Fault System written by Peter Owen Gold and published by . This book was released on 2018 with total page 828 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geologic slip histories measure the frequency, rate and magnitude of past displacement along active faults. Projected into the near future, they inform potential seismic hazard over human time scales. In this dissertation I describe the results of four projects focused on developing slip histories for active faults within the complex southern San Andreas Fault plate boundary system in southern California and northern Baja California, Mexico. Slip is accommodated through this densely populated region by multiple concurrently active faults. For the Banning Fault, a primary subsidiary strand of the southern San Andreas Fault, I report the first, and only, constraint on recent geologic slip. The ~4-5 mm/a mid-Holocene slip rate shows that the Banning Fault is less dominant than previously thought, significantly clarifying how slip is partitioned between three primary structures along the section of the San Andreas Fault that is most likely to host the next major earthquake. In northern Baja California, I report the first quantitatively constrained slip history for the Agua Blanca Fault, one of two primary structures transferring dextral plate motion from the Gulf of California rift to faults that parallel the Pacific coast. I report rates from three sites along the Agua Blanca Fault that indicate time-invariant slip of 2.8 +0.8/-0.6 mm/a since ~65.1 ka, 3.0 +1.4/-0.8 mm/a since ~21.8 ka, 3.4 +0.8/-0.6 mm/a since ~11.7 ka, and 3.0 +3.0/-1.5 mm/a since ~1.6 ka. I also report the timing of 7 Holocene earthquakes that suggest maximum earthquake recurrence of ~1000 years, and I report geologic evidence of ~2.5 m of slip in the past two earthquakes, which suggests that the Agua Blanca Fault is capable of accommodating >M7 surface rupturing earthquakes. This new, comprehensive slip history significantly clarifies both on- and off-shore slip partitioning within this part of the Pacific-North American plate boundary. Finally, slip rate and earthquake timing measurements critically depend on geochronologic dating of offset geologic landforms that record past displacement. To evaluate the variability between dates measured using different methods, I report a critical comparison of independent geochronometers that informs best dating practices and demonstrates that discordance often quantifies geomorphic process.

Download or read book Oak Ridge Fault Ventura Basin California written by Robert S. Yeats and published by . This book was released on 1988 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Latest Quaternary Slip History of the Central Altyn Tagh Fault NW China Derived from Faulted Terrace Risers written by Ryan Daniel Gold and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The active, left-lateral Altyn Tagh Fault defines the northwestern margin of the Tibetan Plateau (NW China) and is one of several first order strike-slip faults within the Indo-Asian orogen. Based on its length (>1200 km), total offset (360-475 km), initiation age (ca 49 Ma), and depth (upper mantle), it is arguably the most important structure accommodating Indo-Asian convergence north of the Himalaya. To resolve the late Quaternary slip rate along the central (85-90°E) portion of this fault system and also to resolve potential secular variation in slip, I have determined its post-16 ka slip history using morphochronology (the study of dated and displaced landforms). I began by systematically characterizing the uncertainties associated with determining slip rates from laterally faulted terrace risers. One source of previously uncharacterized uncertainty centers on constraining the magnitude of lateral erosion of a displaced terrace riser. I then obtained new morphochronologic data from 8 risers at 4 slip-rate sites: Kelutelage, Tuzidun, Yukuang, and Keke Qiapu. These new data, in combination with a related result from this study at Yuemake (1 riser), tripled the morphochronologic constraints on the ATF faulting history. I analyzed this large volume of data by developing a new Monte Carlo modeling approach for determining (1) a precise average slip rate and (2) a slip history from which secular variations in slip can be quantified. Results from the modeling yield an average slip rate of 9.1 " 1.1 mm/yr from 16.6 " 3.9 ka to present, which is the most tightly constrained slip rate reported for the ATF. Furthermore, the analysis reveals a pulse of accelerated strain release in the mid Holocene that is a factor of 3 greater than the average slip rate. This accelerated strain release is interpreted to represent a cluster of 2-6,>Mw 7.2 earthquakes in an 800 yr period and is the first such clustered earthquake series detected using morphochronologic techniques. This result highlights the utility of integration and analyzing morphochronologic datasets to quantitatively resolve temporally uniform and secularly varying late Quaternary fault slip records.

Download or read book Analysis of Quaternary Faults and Associated Deformation of Sedimentary Basin Fill written by Jonathan Thomas Bennett and published by . This book was released on 2012 with total page 65 pages. Available in PDF, EPUB and Kindle. Book excerpt: The San Andreas fault system is distributed across hundreds of kilometers in southern California. This transform system includes offshore faults along the shelf, slope and across the Gulf of Santa Catalina basin (GSCB) - comprising part of the Inner California Continental Borderland. Previously, offshore faults have been interpreted as being discontinuous and striking parallel to the coast between Long Beach and San Diego. Our work, based on several thousand kilometers of deep-penetration industry multi-channel seismic reflection data (MCS) as well as high resolution U.S. Geological Survey MCS, indicates that many of the offshore faults are more geometrically continuous than previously reported including Newport-Inglewood (NI)-San Mateo-Carlsbad(SMC), and Coronado Bank Detachment(CBD)-Descanso faults. We interpret a ~18 km wide step over from the NI-SMC positive flower structure in the north to the CBD-Descanso negative flower structure in the south adjacent to San Diego. These faults and stratigraphic interpretations were gridded and depth converted for modeling slip amounts and orientation on the San Mateo-Carlsbad fault. Stratigraphic interpretations of MCS profiles included the ca. 1.8 Ma Top Lower Pico (TLP), which was correlated from wells located offshore Long Beach (Sorlien et al 2010). Based on this age constraint, four younger (Late) Quaternary unconformities (Q1,Q2,Q3,Q4) are interpreted through much of GSCB. We correlate the Q horizons to core hole data in Los Angeles harbor and constrain their ages: Q1 is 160-300; ka Q2 is 300 ka; Q3 300-450 ka; and Q4 ~600 ka. These ages are an order of magnitude older than interpretations published by Covault and Romans (2009). Assuming the ages that were used to calculate slip are correct, we estimate an average slip rate of ~0.44mm/yr on the San Mateo-Carlsbad with an average azimuth direction of 169° which is significantly less than when calculated with younger interpreted ages and indicates that the SMC fault is a right-lateral strike-slip fault. Our modeling also indicates that the SMC fault is kinematically continuous with a right stepover at its southern extent. This change in SMC strike marks a boundary between transpression in the north and transtension in the south and is significant to understanding future tectonic episodes.

Download or read book Testing for Quaternary Fault Slip Rate Variability on the Southern San Jacinto Fault Zone California written by Kimberly Diem Chi Blisniuk and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the mechanics of plate boundaries and associated seismic hazards requires evaluation of how slip is distributed over Quaternary timescales along individual faults, across fault zones, and entire fault systems. Documenting such slip distributions over multiple time scales is challenging due to the difficultly of obtaining reliable ages for offset landforms. For instance, exposure ages from cosmogenic isotopes can be significantly affected by surface processes, and U-series dating of pedogenic carbonate provides only minimum ages because carbonate accumulation occurs after deposition. Fortunately, the controlling factors for the resulting age and age uncertainties of each method are relatively independent from each other, so a combination of cosmogenic isotope and U-series dating may significantly improve the reliability of landform dating and yield more reliable slip rate estimates. To understand how deformation is shared across the Pacific and North American plate boundary, a comprehensive slip rate history is presented at multiple locations and time-intervals from 6 sites across the paired Clark and Coyote Creek faults of the southern San Jacinto fault zone. Offsets are constrained from field mapping and high-resolution LiDAR topography data, and displaced alluvial fans were dated with U-series on pedogenic carbonate clast-rinds and/or in situ cosmogenic 10Be. In general, these results show that, in an arid setting where post-depositional processes are limited and multiple dating techniques can be applied, self-consistent landform ages may be obtained to yield reliable slip rate estimates. The results from this study show that (1) the rate of deformation across the southern San Jacinto fault zone has remained uniform and constant in time and space over at least the past 40 kyr, and probably since its early Quaternary initiation, (2) pronounced slip rate gradients exist along the length of both the Clark and Coyote Creek faults, declining from the northwest to the southeast, and (3) summed slip rates of ~13 to 17 mm/yr across the bedrock portion of southern San Jacinto fault zone suggests that since at least the latest Pleistocene, deformation across the Pacific-North America plate boundary has been partitioned fairly evenly between the southern San Andreas fault zone and San Jacinto fault zone.

Download or read book Abstracts of North American Geology written by and published by . This book was released on 1968 with total page 966 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The San Andreas Fault System written by Robert E. Powell and published by Geological Society of America. This book was released on 1993 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors of the ten chapters in this volume critically examine the geologic evidence that constrains timing and magnitude of movement on various faults of the San Andreas system, and they develop and discuss paleogeologic reconstructions based on these constraints. The volume offers new insight into the evolution of the San Andreas fault system,

Download or read book Geologic Evolution of the Mojave Desert and Southwestern Basin and Range written by Allen F. Glazner and published by Geological Society of America. This book was released on 2002 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: CD-ROM contains: Electronic version of text -- Maps.

Download or read book Tectonics of Strike slip Restraining and Releasing Bends written by W. D. Cunningham and published by Geological Society of London. This book was released on 2007 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume addresses the tectonic complexity and diversity of strike-slip restraining and releasing bends with 18 contributions divided into four thematic sections: a topical review of fault bends and their global distribution; bends, sedimentary basins and earthquake hazards; restraining bends, transpressional deformation and basement controls on development; releasing bends, transtensional deformation and fluid flow.

Download or read book Mineral Resources of the Mecca Hills Wilderness Study Area Riverside County California written by Douglas M. Morton and published by . This book was released on 1988 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book California Indian Languages written by Victor Golla and published by Univ of California Press. This book was released on 2011-09-20 with total page 395 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Victor Golla has been the leading scholar of California Indian languages for most of his professional life, and this book shows why. His ability to synthesize centuries of fieldwork and writings while bringing forward new ideas and fresh ways of looking at California’s famous linguistic diversity will make this the primary text for anyone interested in California languages."--Leanne Hinton, Professor Emerita of Linguistics, University of California, Berkeley and author of How to Keep Your Language Alive “This book is a wonderful contribution that only Golla could have written. It is a perfect confluence of author and subject matter.”--Ives Goddard, Senior Linguist, Emeritus, Smithsonian Institution "Golla is a gifted polymath and California Indian Languages is certainly his landmark achievement, required reading for any linguist, archaeologist, ethnographer, or historian interested in aboriginal California."--Robert L. Bettinger, Professor of Anthropology, University of California Davis and author of Hunter-Gatherer Foraging "The preeminent figure in his field, Victor Golla has written a masterpiece filled with treasures for every audience: Indian communities working toward cultural and linguistic revival; general readers interested in the many cultures of Native California; and scholars in the fields of language, archaeology, and prehistory. The information here is so detailed that it supersedes all previous reference works."--Andrew Garrett, Professor of Linguistics, University of California Berkeley and Director, Survey of California and Other Indian Languages “This is a truly magnificent work, at once authoritative, comprehensive, accessible to a wide readership, and fascinating. Masterfully integrating linguistic, archaeological, historical, and cultural information, the author describes not just the languages, but also the major figures in the story: speakers, explorers, missionaries, and scholars. It is beautifully written, a great pleasure to read, and difficult to put down."--Marianne Mithun, author of The Languages of Native North America

Download or read book United States Earthquakes 1968 written by Jerry L. Coffman and published by . This book was released on 1984 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Climate Change Impacts on High Altitude Ecosystems written by Münir Öztürk and published by Springer. This book was released on 2015-05-05 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers studies on the systematics of plant taxa and will include general vegetational aspects and ecological characteristics of plant life at altitudes above 1000 m. from different parts of the world. This volume also addresses how upcoming climate change scenarios will impact high altitude plant life. It presents case studies from the most important mountainous areas like the Himalayas, Caucasus and South America covering the countries like Malaysia, Sri Lanka, India, Nepal, Pakistan, Kirghizia, Georgia, Russia,Turkey, Indonesia, Malaysia and the Americas. The book will serve as an invaluable resource source undergraduates, graduate students, and researchers.

Download or read book Roadside Geology of Southern California written by Arthur G. Sylvester and published by Roadside Geology. This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since Mountain Press started the Roadside Geology series forty years ago, southern Californians have been waiting for an RG of their own. During those four decades�which were punctuated by jarring earthquakes and landslides�geologists continued to unravel the complexity of the Golden State, where some of the most dramatic and diverse geology in the world erupts, crashes, and collides. With dazzling color maps, diagrams, and photographs, Roadside Geology of Southern California takes advantage of this newfound knowledge, combining the latest science with accessible stories about the rocks and landscapes visible from winding two-lane byways as well as from the region�s vast network of highways. Join Arthur Sylvester, an award-winning UC Santa Barbara geologist, and Elizabeth O�Black Gans, a geologist-illustrator, as they motor through mountains and deserts to explore the iconic features of the SoCal landscape, from boulder piles in Joshua Tree National Park and brilliant white dunes in the Channel Islands to tar seeps along the rugged coast and youthful cinder cones in the Mojave Desert. Whether you want to find precious gemstones, ponder the mysteries of the Salton Sea, or straddle the boundary between the North American and Pacific Plates, be sure to bring this book along as your tour guide.