Download or read book Exploration of the Holocene Record of Fault Slip for the Mojave Section of the San Andreas Fault written by Teresa Compton O'Banion and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Measuring histories of fault slip spanning multiple (10-100) ruptures has the potential to advance understanding of fault and fault-system behavior, including temporal variations in the rate of strain release. The Mojave section of the San Andreas fault (MSAF) shows an apparent discrepancy between slip rates where reported geodetic rates are systematically slower relative to geologic rates. Resolving this discrepancy is important for determining whether or not the MSAF exhibits temporal changes in slip. Paleoseismic data along the MSAF suggest temporal variations in strain release over the last 2 ka, but more studies are needed to extend the slip history back in time. Here we address the problem of the apparent slip rate discrepancy and possible temporal variations in strain release by employing Monte Carlo analysis of previously reported displacement-time data to investigate the extent to which these data constrain the Holocene slip history. We evaluated 42 previously reported piercing lines for possible inclusion in our analysis, 15 of which were unused because they are either duplicate reports or poorly documented. The remaining 27 data points reveal that slip rates are nonexistent for five offset distances (19-27m, 33-42m, 45-63m, 65-129m, and 131-300m) and for three time periods from 10-3.9 ka, 3.9-2.8 ka, and 2.8-1.4 ka. Results of this analysis suggest slip rate along the MSAF varied between 0 and 4.5 ka, with five possible phases of strain release, 3 of which are faster than the average of ~30 mm yr−1. The oldest fast phase was from 4.5-2.9 ka with an average slip rate of 61 506/40 mm yr−1. The next fast phase, with an average rate of 81 54/3 mm yr−1, was from 1.5-1.1 ka. The youngest fast phase resulted in a rate of 38 +12/−11 mm yr−1 between 0.4 ka and the 1857 event. Slower phases of slip occurred from 2.9-1.5 ka, with an average rate of 12 +12/−5 mm yr−1, and from 1.1-0.4 ka, with a slip rate of 20 +9/− mm yr−1. These slip history findings are considered preliminary because they are based on a limited dataset that contains data gaps. To aide in our search for additional potentially dateable offsets preserved along the MSAF, we used available airborne LiDAR and virtual-reality visualization software Crusta. Crusta is a virtual globe application that supports real-time interactive visualization of large (>60GB) LiDAR digital elevation models and merges the mapping functionality of ArcMap with the terrain visualization capabilities of GoogleEarth. On a 100-km section of the MSAF we found 60 offsets ranging from 20 to 297 m, many of which show promise as potential slip-rate sites. We determined offset uncertainties using the slicer tool, which is a recently developed function in Crusta that allows the user to assign a fault plane by dropping nodes along a linear fault trace and interactively moving one fault block relative to the other in any slip direction. This functionality allows the user to incrementally restore fault slip until topographic features on opposite sides of the fault are aligned. This tool has been helpful in identifying, evaluating, and reconstructing possible landform offsets. This work provides the necessary foundation for future geochronologic measurements and thus is the critical first step in refining and completing the slip history of the MSAF.
Download or read book The Influence of Climate Variability on Records of Holocene Slip Rate written by Emery Orion Anderson-Merritt and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Slip rates on the Mojave San Andreas fault (MSAF) are not well understood, but are useful for evaluating seismic hazard and for understanding how regional fault systems develop and interact. Here I calculate a minimum slip rate at the Pearblossom site of 17 mm/yr and a maximum slip rate of 76 mm/yr by reconstructing a beheaded channel that has been offset by 34 ± 2 to 81 ± 2 m since between 1.44 ± 0.43 ka and 1.27 ± 0.18 ka, as determined by feldspar infrared stimulated luminescence dating. A pulse of aggradation at ~0.6 ka both upstream and downstream of the fault at Pearblossom suggests that in addition to fault slip, climate has influenced deposition at the site. Comparison of charcoal ages from slip rate sites, paleoseismic sites, and lake records with records of Southern California climate from sedimentological features of lake cores indicates that changes in precipitation drive sediment deposition and channel incision events on the MSAF. This relationship has two important implications for slip rate studies. First, markers of offset may not form during dry periods. Second, pulses of aggradation during wet periods may complicate site reconstructions and produce offsets that appear to be caused by fault slip but are instead caused by incision or deposition in a deflected configuration. Channel deflection morphology and upstream channel position can provide an indication of whether a site is likely to record useful information about fault slip. A deflected channel that is narrow relative to the width of its deflection is likely to have incised in a deflected configuration. For a right-lateral fault, a deflected channel incised on the left side of an alluvial fan gives a minimum offset measurement, while a deflected channel incised on the right side gives a maximum offset measurement.
Download or read book A Study of Holocene Displacement History Along the South central Reach of the San Andreas Fault written by Kerry E. Sieh and published by . This book was released on 1977 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Holocene Geologic Slip Rate for the Mission Creek Strand of the Southern San Andreas Fault CA written by Rosemarie C. Fryer and published by . This book was released on 2016 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: The San Andreas Fault is the primary structure accommodating relative plate motions between the Pacific and North American plates along the southwestern margin of North America. The northern San Andreas Fault (SAF) segment ruptured in 1906 and the central segment releases strain primarily by continuous creep. The south-central Mojave section of SAF ruptured in 1857, but the Coachella Valley section farthest south has not ruptured historically. The Coachella Valley section is therefore considered overdue for an earthquake because it has exceeded its average recurrence interval of ~150-200 years. In the northern Coachella Valley, the Southern SAF (SSAF) splays into three fault strands: the Mission Creek, Banning, and Garnet Hill strands. The NW-striking Mission Creek strand extends from the Indio Hills into the San Bernardino Mountains, whereas the Banning and Garnet Hill strands strike WNW and transfer slip into the San Gorgonio Pass region. Together, the three faults accommodate ~20 mm/yr of right-lateral motion based on geodetic measurements. Determining how slip is partitioned between these faults and how the slip rates have varied over different timescales is critical for southern California seismic hazard models. The purpose of this project was to establish a Holocene geologic slip rate for the Mission Creek strand of the SSAF at the Three Palms slip rate site in the southeast Indio Hills. At the Three Palms Site, located northwest of Biskra Palms, three alluvial fans sourced from three distinct catchments have been offset by the Mission Creek strand. The central portion of these fans is best preserved and records a right lateral displacement of ~57 ± 3 meters. Uranium-series dating of pedogenic carbonate rinds constrain the minimum depositional age of this fan. U-series dates give a standard corrected weighted mean average of 3.49 ± 0.92 ka, yielding a maximum slip rate of 16 +6.1/-3.8 mm/yr. Three samples from an individual clast give a nearly identical isochron age of 3.3 ± 0.6 ka, which provides confidence in the weighted average age. This Holocene maximum slip rate overlaps within error of the previously determined late Pleistocene slip rate measured at Biskra Palms of 12-22 mm/yr, suggesting that the Mission Creek strand slip rate has remained constant over these timescales and that it has remained the dominant fault accommodating slip at the southeast Indio Hills over the past ~50 kyr.
Download or read book The San Andreas Fault System in the Vicinity of the Central Transverse Ranges Province Southern California written by Jonathan C. Matti and published by . This book was released on 1992 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The San Andreas Fault System California written by and published by . This book was released on 1990 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overview of the history, geology, geomorphology, geophysics, and seismology of the most well known plate tectonic boundary in the world.
Download or read book Integrated Structural and Geomorphic Evolution of Displaced Fluvial Channels Along the Mojave San Andreas and Their Implications for Measurements of Slip Rate written by Mary Alice Barr and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Holocene slip history for the Mojave section of the San Andreas Fault (MSAF) currently has gaps in the available slip rate data between 2.5 kyr and 12 kyr. Additional estimates of slip rate are needed on the MSAF to construct an accurate Holocene slip history. Traditional slip rate studies use offset geomorphic features to determine the age and magnitude of offset on active faults to calculate a rate of slip. These slip rate estimates can carry large aleatoric and epistemic uncertainties and in some cases these uncertainties cannot be quantified. This study illustrates the complexities of determining age and offset measurements from fluvial systems by providing a detailed account of the age data, offset data, and sources of uncertainty at three newly identified deflected and beheaded channels (Pine Canyon, Randall Ranch, and Collins Canyon) along the northern MSAF. These three slip rate investigations include ages ranging from 0 to12376 yr CalBP (95%) and offset measurements between 27 and 400 meters. In addition to the age and offset data at the three sites, I observed particularly high rates of incision ranging from ~1.78 to 10.4 mm/yr and rates of deposition ranging from ~0.5 to ~4.75 mm/yr. To synthesize and guide my observations and interpretations, I developed a depositional and deformational model for the three sites. I use this model along with the age and offset data from deflected and beheaded channels to reconstruct the geomorphic features and fault configurations at the three sites. The offset reconstructions and geochronologic data from this analysis were used to calculate slip rate estimates. For Pine Canyon the age and offset data equated to slip rate estimates of >16 to 56.3 mm/yr and
Download or read book Holocene Slip Rate and Recurrence of Surface faulting Earthquakes on the Northern Calaveras Fault at Leyden Creek Alameda County California written by and published by . This book was released on 1994 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Geologic Slip Rates Since Early Pleistocene Initiation of the San Jacinto and San Felipe Fault Zones in the San Andreas Fault System Southern California USA written by and published by Geological Society of America. This book was released on 2010-01-01 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The San Jacinto right-lateral strike-slip fault zone is crucial for understanding plate-boundary dynamics, regional slip partitioning, and seismic hazards within the San Andreas fault system of southern California, yet its age of initiation and long-term average slip rate are controversial. This synthesis of prior and new detailed studies in the western Salton Trough documents initiation of structural segments of the San Jacinto fault zone at or slightly before the 1.07 Ma base of the Jaramillo subchron. In Special Paper 475, five new estimates of displacement are developed using offset successions of crystalline rocks; distinctive marker beds in the late Cenozoic basin fill; analysis of strike-slip-related fault-bend folds; quantification of strain in folds at the tips of dextral faults; and gravity, magnetic, and geomorphic data sets."--Publisher's website.
Download or read book Preliminary Report on the Late Holocene Slip Rate Along the Central Calaveras Fault Southern San Francisco Bay Area Gilroy California written by and published by . This book was released on 2002 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Paleoseismic and Geoarchaeologic Investigations of the Northern San Andreas Fault Fort Ross State Historic Park California written by and published by . This book was released on 1993 with total page 42 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 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 Displacement Along the San Andreas Fault California written by John C. Crowell and published by Geological Society of America. This book was released on 1962 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Paleoseismic Investigations of the Northern San Andreas Fault at the Vedanta Site Marin County California written by Nelson Timothy Hall and published by . This book was released on 1994 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Where s the San Andreas Fault written by Philip Ward Stoffer and published by . This book was released on 2006 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Publications of the Geological Survey written by Geological Survey (U.S.) and published by . This book was released on 1984 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt:
