USGS Open-File Report 2004-1424
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Land Resources
3.2 Land Resources 3.2 Land Resources 3.2.1 Geologic Setting The project site is located within the Coast Range Geomorphic Province of California. The topography of the province is characterized by mountain ranges with intervening valleys trending to the northwest, roughly paralleling the Pacific coastline. The project site is located in the northern portion of the Alexander Valley, which in the area is also referred to locally as the Cloverdale Valley. The Alexander Valley is likely a sediment-filled valley that has been pulled apart by the Maacama and the Healdsburg Fault Zones. Elevation of the project site ranges from approximately 302 to 332 feet above mean sea level, sloping in a southeasterly direction. The project site lies within the eastern flank of the northern Coast Ranges, which is underlain by the Franciscan Complex, an assemblage of igneous, sedimentary, and metamorphic rocks. Bedrock underlying the project area is about 50 feet to 60 feet deep and consists of fractured dark greenish-gray shale of the Franciscan Formation. Overlying the bedrock assemblages in the project region are younger (10,000 to 1.6 million years old) alluvium and river channel deposits consisting of various clay, silt, sand, and gravel mixtures. Boring logs revealed that these alluvial sediments occur generally as alternating sandy clay mixtures and gravels from the surface to the interface with the bedrock. The sediment transport and depositional history of the Russian River has controlled the placement of the alluvial sediments and the horizontal and vertical distribution of these materials (Appendix K). 3.2.2 Soils Figure 3.2-1 provides a map of soils on the project site. -
Introduction San Andreas Fault: an Overview
Introduction This volume is a general geology field guide to the San Andreas Fault in the San Francisco Bay Area. The first section provides a brief overview of the San Andreas Fault in context to regional California geology, the Bay Area, and earthquake history with emphasis of the section of the fault that ruptured in the Great San Francisco Earthquake of 1906. This first section also contains information useful for discussion and making field observations associated with fault- related landforms, landslides and mass-wasting features, and the plant ecology in the study region. The second section contains field trips and recommended hikes on public lands in the Santa Cruz Mountains, along the San Mateo Coast, and at Point Reyes National Seashore. These trips provide access to the San Andreas Fault and associated faults, and to significant rock exposures and landforms in the vicinity. Note that more stops are provided in each of the sections than might be possible to visit in a day. The extra material is intended to provide optional choices to visit in a region with a wealth of natural resources, and to support discussions and provide information about additional field exploration in the Santa Cruz Mountains region. An early version of the guidebook was used in conjunction with the Pacific SEPM 2004 Fall Field Trip. Selected references provide a more technical and exhaustive overview of the fault system and geology in this field area; for instance, see USGS Professional Paper 1550-E (Wells, 2004). San Andreas Fault: An Overview The catastrophe caused by the 1906 earthquake in the San Francisco region started the study of earthquakes and California geology in earnest. -
(Ver. 1.1): Hydrogeologic Controls and Geochemical Indicators Of
Prepared in cooperation with the East Bay Municipal Utility District, City of Hayward, and Alameda County Water District Hydrogeologic Controls and Geochemical Indicators of Groundwater Movement in the Niles Cone and Southern East Bay Plain Groundwater Subbasins, Alameda County, California Scientific Investigations Report 2018–5003 Version 1.1, February 2019 U.S. Department of the Interior U.S. Geological Survey Hydrogeologic Controls and Geochemical Indicators of Groundwater Movement in the Niles Cone and Southern East Bay Plain Groundwater Subbasins, Alameda County, California By Nick Teague, John Izbicki, Jim Borchers, Justin Kulongoski, and Bryant Jurgens Prepared in cooperation with the East Bay Municipal Utility District, City of Hayward, and Alameda County Water District Scientific Investigations Report 2018–5003 Version 1.1, February 2019 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior DAVID BERNHARDT, Acting Secretary U.S. Geological Survey William H. Werkheiser, Deputy Director exercising the authority of the Director U.S. Geological Survey, Reston, Virginia: 2019 First release: February 2018 Revised: February 2019 (ver. 1.1) For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit http://www.usgs.gov or call 1–888–ASK–USGS. For an overview of USGS information products, including maps, imagery, and publications, visit http://store.usgs.gov. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. -
Revised Plates
DRAFT BART SILICON VALLEY PHASE II SANTA CLARA EXTENSION PROJECT GEOTECHNICAL MEMORANDUM P REPARED FOR: Santa Clara Valley Transportation Authority Federal Transit Administration P REPARED BY: Company Name: PARIKH Consultants, Inc. Address: 2630 Qume Drive, Suite A, San Jose, CA 95131 February 2014 PARIKH Consultants, Inc. 2014. BART Silicon Valley Phase II Santa Clara Extension Project Geotechnical Memorandum. Draft. February. San Jose, CA. Prepared for the Santa Clara Valley Transportation Authority, San Jose, CA, and the Federal Transit Administration, Washington, D.C. This Geotechnical Memorandum was prepared in 2014 to identify mitigation strategies for the early alternatives and station plans being considered at that time. However, the mitigation measures identified in this memorandum are relevant to the current proposed project and have been incorporated into the SEIS/SEIR as appropriate. Contents Page Chapter 1 Project Description ..................................................................................................1-1 1.1 Alignment and Station Features by City ........................................................... 1-1 1.1.1 City of San Jose................................................................................................... 1-1 1.1.2 City of Santa Clara ................................................................................... 1-1 1.2 VTA's Transit-Oriented Development (CEQA Only).............................................. 1-1 Chapter 2 Previous Studies Conducted ...................................................................................2-1 -
Sonoma Gounty Residents Face Big Challenges
July 8, 2019 TAC Mtg Agenda Item #5 Attachment 1 WILL THERE BE WATER AFTER AN EARTHQUAKE? Sonoma Gounty Residents Face Big Challenges SUMMARY When the next earthquake arrives, will we have enough water? Engineers say our water supplies will probably be disrupted after a major earthquake. In Sonoma County, most people rely on water supplied by Sonoma Water (formerly known as the Sonoma County Water Agency) to nine city contractors and special districts, and they, in turn, deliver water to residents, businesses, and organizations within their areas. The Sonoma County Civil Grand Jury has investigated how well-prepared Sonoma Water is to respond to a major earthquake. Our report seeks to answer this crucial question: What plans and resources are in place in the event of a major earthquake, to provide drinking water to residents of the county who receive water from Sonoma Water? The Russian River is the primary source of water for Sonoma County and northern Marin County. Sonoma Water supplies 90%o of the pressurized water used in nine contracting cities and water agencies (Santa Rosa, Windsor, Cotati, Rohnert Park, Petaluma, City of Sonoma, Valley of the Moon Water District, Marin Municipal Water District, North Marin Water District) that together serve over 600,000 customers. Water flows through a network of pumps, pipes, and valves to its final destination in our homes, hospitals, schools, and businesses. Sonoma Water projects that a minor earthquake (5.0 or less) will not impair water supply operations or services, and will not present immediate danger to the health and welfare of the public. -
Region of the San Andreas Fault, Western Transverse Ranges, California
Thrust-Induced Collapse of Mountains— An Example from the “Big Bend” Region of the San Andreas Fault, Western Transverse Ranges, California By Karl S. Kellogg Scientific Investigations Report 2004–5206 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior Gale A. Norton, Secretary U.S. Geological Survey Charles G. Groat, Director U.S. Geological Survey, Reston, Virginia: 2004 For sale by U.S. Geological Survey, Information Services Box 25286, Denver Federal Center Denver, CO 80225 For more information about the USGS and its products: Telephone: 1-888-ASK-USGS World Wide Web: http://www.usgs.gov/ Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. iii Contents Abstract ……………………………………………………………………………………… 1 Introduction …………………………………………………………………………………… 1 Geology of the Mount Pinos and Frazier Mountain Region …………………………………… 3 Fracturing of Crystalline Rocks in the Hanging Wall of Thrusts ……………………………… 5 Worldwide Examples of Gravitational Collapse ……………………………………………… 6 A Spreading Model for Mount Pinos and Frazier Mountain ………………………………… 6 Conclusions …………………………………………………………………………………… 8 Acknowledgments …………………………………………………………………………… 8 References …………………………………………………………………………………… 8 Illustrations 1. Regional geologic map of the western Transverse Ranges of southern California …………………………………………………………………………… 2 2. Simplified geologic map of the Mount Pinos-Frazier Mountain region …………… 2 3. View looking southeast across the San Andreas rift valley toward Frazier Mountain …………………………………………………………………… 3 4. View to the northwest of Mount Pinos, the rift valley (Cuddy Valley) of the San Andreas fault, and the trace of the Lockwood Valley fault ……………… 3 5. -
4.5 Geological Resources
Cotati Downtown Specific Plan GEOLOGICAL RESOURCES Draft EIR 4.5 GEOLOGICAL RESOURCES 4.5.1 Issues Although implementation of the DSP will improve buildings in the planning area relative to geologic and seismic safety by upgrading structures or developing new structures subject to current building codes, implementation of the plan will also induce population growth and development in a seismically active area. The evaluation that follows provides a general characterization of the seismic setting, soil types, and associated hazards and risks in the planning area. This analysis is not intended as a substitute for site-specific geotechnical reports that may be required for individual projects in the DSP area under the Uniform Building Code (UBC). Additional study may be required to obtain site-specific data, and to determine the appropriate engineering recommendations based on a particular building’s size, design, and use. 4.5.2 Setting Regional (Structural) Geology California is divided geologically into several physiographic or geomorphic provinces, including the Sierra Nevada range, the Central (Great) Valley, the Transverse Ranges, the Coast Ranges, and others. Cotati lies within the Coast Ranges geomorphic province of California. The Coast Range was formed at the intersection of two tectonic plates: the Pacific to the west, and the North American to the east. The compressive and shearing motions between the tectonic plates resulted in a complex system of active strike-slip faults, reverse faults, thrust faults and related folds (bends in rock layers). Locally, the Coast Ranges are characterized by northwest trending valleys and basins. Cotati is located in the topographic area known as the Cotati Valley. -
I Final Technical Report United States Geological Survey National
Final Technical Report United States Geological Survey National Earthquake Hazards Reduction Program - External Research Grants Award Number 08HQGR0140 Third Conference on Earthquake Hazards in the Eastern San Francisco Bay Area: Science, Hazard, Engineering and Risk Conference Dates: October 22nd-26th, 2008 Location: California State University, East Bay Principal Investigator: Mitchell S. Craig Department of Earth and Environmental Sciences California State University, East Bay Submitted March 2010 Summary The Third Conference on Earthquake Hazards in the Eastern San Francisco Bay Area was held October 22nd-26th, 2008 at California State University, East Bay. The conference included three days of technical presentations attended by over 200 participants, a public forum, two days of field trips, and a one-day teacher training workshop. Over 100 technical presentations were given, including oral and poster presentations. A printed volume containing the conference program and abstracts of presentations (attached) was provided to attendees. Participants included research scientists, consultants, emergency response personnel, and lifeline agency engineers. The conference provided a rare opportunity for professionals from a wide variety of disciplines to meet and discuss common strategies to address region-specific seismic hazards. The conference provided participants with a comprehensive overview of the vast amount of new research that has been conducted and new methods that have been employed in the study of East Bay earthquake hazards since the last East Bay Earthquake Conference was held in 1992. Topics of presentations included seismic and geodetic monitoring of faults, trench-based fault studies, probabilistic seismic risk analysis, earthquake hazard mapping, and models of earthquake rupture, seismic wave propagation, and ground shaking. -
Nehrp Final Technical Report
NEHRP FINAL TECHNICAL REPORT Grant Number: G16AP00097 Term of Award: 9/2016-9/2017, extended to 12/2017 PI: Whitney Maria Behr1 Quaternary geologic slip rates along the Agua Blanca fault: implications for hazard to southern California and northern Baja California Abstract The Agua Blanca and San Miguel-Vallecitos Faults transfer ~14% of San Andreas-related Pacific-North American dextral plate motion across the Peninsular Ranges of Baja California. The Late Quaternary slip histories for the these faults are integral to mapping how strain is transferred by the southern San Andreas fault system from the Gulf of California to the western edge of the plate boundary, but have remained inadequately constrained. We present the first quantitative geologic slip rates for the Agua Blanca Fault, which of the two fault is characterized by the most prominent tectonic geomorphologic evidence of significant Late Quaternary dextral slip. Four slip rates from three sites measured using new airborne lidar and both cosmogenic 10Be exposure and optically stimulated luminescence geochronology suggest a steady along-strike rate of ~3 mm/a over 4 time frames. Specifically, the most probable Late Quaternary slip rates for the Agua Blanca Fault are 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 ~11.8 ka, and 3.0 +3.0/-1.5 mm/a since ~1.6 ka, with all uncertainties reported at 95% confidence. These rates suggest that the Agua Blanca Fault accommodates at least half of plate boundary slip across northern Baja California. -
Structural Superposition in Fault Systems Bounding Santa Clara Valley, California
A New Three-Dimensional Look at the Geology, Geophysics, and Hydrology of the Santa Clara (“Silicon”) Valley themed issue Structural superposition bounding Santa Clara Valley Structural superposition in fault systems bounding Santa Clara Valley, California R.W. Graymer, R.G. Stanley, D.A. Ponce, R.C. Jachens, R.W. Simpson, and C.M. Wentworth U.S. Geological Survey, 345 Middlefi eld Road, MS 973, Menlo Park, California 94025, USA ABSTRACT We use the term “structural superposition” to and/or reverse-oblique faults, including the emphasize that younger structural features are Silver Creek Thrust1 (Fig. 3). The reverse and/or Santa Clara Valley is bounded on the on top of older structural features as a result of reverse-oblique faults are generated by a com- southwest and northeast by active strike-slip later tectonic deformation, such that they now bination of regional fault-normal compression and reverse-oblique faults of the San Andreas conceal or obscure the older features. We use the (Page, 1982; Page and Engebretson, 1984) fault system. On both sides of the valley, these term in contrast to structural reactivation, where combined with the restraining left-step transfer faults are superposed on older normal and/or pre existing structures accommodate additional of slip between the central Calaveras fault and right-lateral normal oblique faults. The older deformation, commonly in a different sense the southern Hayward fault (Aydin and Page, faults comprised early components of the San from the original deformation (e.g., a normal 1984; Andrews et al., 1993; Kelson et al., 1993). Andreas fault system as it formed in the wake fault reactivated as a reverse fault), and in con- Approximately two-thirds of present-day right- of the northward passage of the Mendocino trast to structural overprinting, where preexisting lateral slip on the southern part of the Calaveras Triple Junction. -
A Pattern of Seismicity in Southern California: the Possibility of Earthquakes Triggered by Lunar and Solar Gravitational Tides
A Pattern of Seismicity in Southern California: The Possibility of Earthquakes Triggered by Lunar and Solar Gravitational Tides David Nabhan Helen Keller wrote that the heresy of one age is the orthodoxy of the next, giving ample proof that although sightless, she possessed extraordinary vision. Moreover, it has been said that every new fact must pass through a crucible by which first it is ignored or ridiculed, then vigorously attacked, and finally accepted as though the truth had been apparent from the beginning. Earthquake prediction is no exception but for the anomaly that the first two stages have endured far longer than what the immense populations on the U.S. West Coast might hope to expect regarding a matter so important to their safety and welfare. Residents of Southern California have been left with a bewildering set of claims and counter-claims regarding this issue for many decades. While scientific data Seismic Gap Probabilities. Author's collection. can be presented any number of ways to say any number of things, there is another arbiter that, weighed alongside the conflicting findings, may allow fair-minded observers to come to their own cogent conclusions: history. There exists a long and verifiable record of events on the Pacific Coast and elsewhere David Nabhan, SDSU alumnus, is the author of Earthquake Prediction: Answers in Plain Sight (2012) and two other books on the subject. He is directing a public opinion campaign to impel the governor of California to convene the California Earthquake Prediction Evaluation Council for the purposes of determining the viability or fallibility of a seismic safety plan. -
Geologic, Climatic, and Vegetation History of California
GEOLOGIC, CLIMATIC, AND VEGETATION HISTORY OF CALIFORNIA Constance I. Millar I ntroduction The dawning of the “Anthropocene,” the era of human-induced climate change, exposes what paleoscientists have documented for decades: earth’s environment—land, sea, air, and the organisms that inhabit these—is in a state of continual flux. Change is part of global reality, as is the relatively new and disruptive role humans superimpose on environmental and climatic flux. Historic dynamism is central to understanding how plant lineages exist in the present—their journey through time illuminates plant ecology and diversity, niche preferences, range distributions, and life-history characteristics, and is essential grounding for successful conservation planning. The editors of the current Manual recognize that the geologic, climatic, and vegetation history of California belong together as a single story, reflecting their interweaving nature. Advances in the sci- ences of geology, climatology, and paleobotany have shaken earlier interpretations of earth’s history and promoted integrated understanding of the origins of land, climate, and biota of western North America. In unraveling mysteries about the “what, where, and when” of California history, the respec- tive sciences have also clarified the “how” of processes responsible for geologic, climatic, and vegeta- tion change. This narrative of California’s prehistory emphasizes process and scale while also portraying pic- tures of the past. The goal is to foster a deeper understanding of landscape dynamics of California that will help toward preparing for changes coming in the future. This in turn will inform meaningful and effective conservation decisions to protect the remarkable diversity of rock, sky, and life that is our California heritage.