Download or read book Determination of Paleoearthquake Age and Slip Per Event Data and Late Pleistocene Holocene Slip Rates on a Blind thrust Fault written by Shari A. Christofferson and published by . This book was released on 2002 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Consensus Preferred Recurrence interval and Vertical Slip rate Estimates written by William R. Lund and published by Utah Geological Survey. This book was released on 2005-06-30 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents the results of the Utah Quaternary Fault Parameters Working Group (hereafter referred to as the Working Group) review and evaluation of Utah’s Quaternary fault paleoseismic-trenching data. The purpose of the review was to (1) critically evaluate the accuracy and completeness of the paleoseismictrenching data, particularly regarding earthquake timing and displacement, (2) where the data permit, assign consensus, preferred recurrence-interval (RI) and vertical slip-rate (VSR) estimates with appropriate confidence limits to the faults/fault sections under review, and (3) identify critical gaps in the paleoseismic data and recommend where and what kinds of additional paleoseismic studies should be performed to ensure that Utah’s earthquake hazard is adequately documented and understood. It is important to note that, with the exception of the Great Salt Lake fault zone, the Working Group’s review was limited to faults/fault sections having paleoseismic-trenching data. Most Quaternary faults/fault sections in Utah have not been trenched, but many have RI and VSR estimates based on tectonic geomorphology or other non-trench-derived studies. Black and others compiled the RI and VSR data for Utah’s Quaternary faults, both those with and without trenches.
Download or read book Seismological Research Letters written by and published by . This book was released on 2001 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Slip rate determination for the Pittsburg blind thrust fault Pittsburg California written by Patrick Williams and published by . This book was released on 1997* with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Holocene Slip Rate and Paleoearthquake History of the Green Valley Fault at Lopes Ranch Creek Cordelia California written by John N. Baldwin and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Determination of Fault Slip Rates Paleoearthquake History and Segmentation of the Warm Springs Valley Fault System written by Craig M. DePolo and published by . This book was released on 2006 with total page 35 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 Paleoseismic Investigation of the Holocene Slip Rate on the Greenville Fault Eastern San Francisco Bay Area California written by Thomas L. Sawyer and published by . This book was released on 2002 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Late Pleistocene holocene Slip Rates in the Northwestern Zagros Mountains Kurdistan Region of Iraq Derived from Luminescence Dating of River Terraces and Structural Modeling written by Mjahid Zebari and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: A significant amount of the ongoing shortening between the Eurasian and Arabian plates is accommodated within the Zagros Fold-Thrust Belt. However, the spatial and temporal distribution of active shortening within the belt, especially in its NW part, is not yet well constrained. We determined depositional ages of uplifted river terraces crossing the belt along the Greater Zab River using luminescence dating. Kinematic modeling of the fault-related fold belt was then used to calculate long-term slip rates during the Late Pleistocene to Holocene. Our results provide new insight into the rates of active faulting and folding in the area. The Zagros Mountain Front Fault accommodates about 1.46 ± 0.60 mm a−1 of slip, while a more external basement fault further to the SW accommodates less than 0.41 ± 0.16 mm a−1. Horizontal slip rates related to detachment folding of two anticlines within the Zagros Foothills are 0.40 ± 0.10 and 1.24 ± 0.36 mm a−1. Basement thrusting and thickening of the crust are restricted to the NE part of the Zagros belt. This is also reflected in the regional topography and in the distribution of uplifted terraces. In the southwestern part, the deformation is limited mainly to folding and thrusting of the sedimentary cover above a Triassic basal detachment. In the NE, deformation is associated with slip on basement thrusts. Our study sheds light on the distribution of shortening in the Zagros Mountains and helps to understand the regional tectonic system. Our results may be the foundation for a better seismic hazard assessment of the entire area
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 Holocene Geologic Slip Rate for the Mission Creek Strand of the Southern San Andreas Fault Indio Hills written by Juan José Muñoz Zapata and published by . This book was released on 2017 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: Slip on the southern San Andreas fault in the northwestern Coachella Valley in Southern California is partitioned among three fault strands: the Mission Creek, Garnet Hill, and Banning 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 W-NW and transfer slip into the San Gorgonio Pass region. Together, these three faults accommodate ~ 20 mm/yr of right-lateral motion based on geodetic slip rate estimates. Determining which strand accommodates the majority of fault slip and how slip rates on these strands have varied over Quaternary timescales is critical to seismic hazard assessment for this region. Here I present a new Holocene geologic slip rate estimate from an offset alluvial fan complex along the Mission Creek fault at the Three Palms site in the Indio Hills. The correlation of offset fans precisely located from a satellite image, confirmed by field mapping and B4 LiDAR indicates that the Three Palms fan complex is offset 50.0 ± 5.0 meters. U-series dating on pedogenic carbonate rinds collected at 25-100 cm depth within the deposit constrain the minimum depositional age to 3.49 ± 0.92 ka (95% CI), yielding a maximum slip rate of 19.2 ± 2.0 mm/yr. Cosmogenic 10Be surface exposure dating on boulders yields a scattered dataset with high apparent inheritance and a median age of 13.6 +6.9/-6.7 ka (1[sigma] error). However, the minimum boulder age of 5.4 ± 1.0 ka (2[sigma] error) was interpreted as the maximum depositional age for the fan. This age, along with the preferred offset of 50.0 meters, yields a minimum slip rate of 7.8 ± 0.8 mm/yr. We therefore estimate a Holocene geologic slip rate of 7-21 mm/yr, with a preferred rate of 9-14 mm/yr. This rate overlaps within error with a previously published late Pleistocene slip rate on the Mission Creek strand of 12-22 mm/yr calculated at Biskra Palms Oasis a few kilometers to the southeast.
Download or read book Post Bonneville Paleoearthquake Chronology of the Salt Lake City Segment Wasatch Fault Zone from the 1999 Megatrench Site written by James McCalpin and published by Utah Geological Survey. This book was released on 2002 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents the results of a paleoseismic investigation designed to date a long series of consecutive earthquakes on the Wasatch fault zone and to measure the variability of recurrence times between the events. Geologists have long recognized that the comparatively short average recurrence interval (compared to most other basin-and-range normal faults) between large surface-faulting earthquakes on the Salt Lake City segment of the Wasatch fault zone during mid- to late-Holocene time is potentially anomalous, and possibly affected by the rise and fall of Lake Bonneville. This study extends the paleoearthquake record back to Bonneville time, nearly doubling the previous record, and provides new information on the timing and periodicity of surface faulting on the Salt Lake City segment from the latest Pleistocene through the Holocene. The trench and accompanying auger hole for this study exposed 26 meters of vertical section, roughly four times that of a typical paleoseismic trench on the Wasatch fault zone, hence the name “Megatrench.”
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 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 Probabilistic Seismic Hazard Assessment for the State of California written by and published by . This book was released on 1996 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Abstracts written by International Union for Quaternary Research. Congress and published by . This book was released on 1995 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt:
