Sample records for valley california earthquake

  1. Revisiting the 1872 Owens Valley, California, Earthquake

    USGS Publications Warehouse

    Hough, S.E.; Hutton, K.

    2008-01-01

    The 26 March 1872 Owens Valley earthquake is among the largest historical earthquakes in California. The felt area and maximum fault displacements have long been regarded as comparable to, if not greater than, those of the great San Andreas fault earthquakes of 1857 and 1906, but mapped surface ruptures of the latter two events were 2-3 times longer than that inferred for the 1872 rupture. The preferred magnitude estimate of the Owens Valley earthquake has thus been 7.4, based largely on the geological evidence. Reinterpreting macroseismic accounts of the Owens Valley earthquake, we infer generally lower intensity values than those estimated in earlier studies. Nonetheless, as recognized in the early twentieth century, the effects of this earthquake were still generally more dramatic at regional distances than the macroseismic effects from the 1906 earthquake, with light damage to masonry buildings at (nearest-fault) distances as large as 400 km. Macroseismic observations thus suggest a magnitude greater than that of the 1906 San Francisco earthquake, which appears to be at odds with geological observations. However, while the mapped rupture length of the Owens Valley earthquake is relatively low, the average slip was high. The surface rupture was also complex and extended over multiple fault segments. It was first mapped in detail over a century after the earthquake occurred, and recent evidence suggests it might have been longer than earlier studies indicated. Our preferred magnitude estimate is Mw 7.8-7.9, values that we show are consistent with the geological observations. The results of our study suggest that either the Owens Valley earthquake was larger than the 1906 San Francisco earthquake or that, by virtue of source properties and/or propagation effects, it produced systematically higher ground motions at regional distances. The latter possibility implies that some large earthquakes in California will generate significantly larger ground motions than San

  2. A public health issue related to collateral seismic hazards: The valley fever outbreak triggered by the 1994 Northridge, California earthquake

    USGS Publications Warehouse

    Jibson, R.W.

    2002-01-01

    Following the 17 January 1994 Northridge. California earthquake (M = 6.7), Ventura County, California, experienced a major outbreak of coccidioidomycosis (CM), commonly known as valley fever, a respiratory disease contracted by inhaling airborne fungal spores. In the 8 weeks following the earthquake (24 January through 15 March), 203 outbreak-associated cases were reported, which is about an order of magnitude more than the expected number of cases, and three of these cases were fatal. Simi Valley, in easternmost Ventura County, had the highest attack rate in the county, and the attack rate decreased westward across the county. The temporal and spatial distribution of CM cases indicates that the outbreak resulted from inhalation of spore-contaminated dust generated by earthquake-triggered landslides. Canyons North East of Simi Valley produced many highly disrupted, dust-generating landslides during the earthquake and its aftershocks. Winds after the earthquake were from the North East, which transported dust into Simi Valley and beyond to communities to the West. The three fatalities from the CM epidemic accounted for 4 percent of the total earthquake-related fatalities.

  3. California: Diamond Valley

    Atmospheric Science Data Center

    2014-05-15

    ... article title:  Watching the Creation of Southern California's Largest Reservoir     ... Valley Lake is designed to provide protection against drought and a six-month emergency supply in the event of earthquake damage to a ...

  4. A Public Health Issue Related To Collateral Seismic Hazards: The Valley Fever Outbreak Triggered By The 1994 Northridge, California Earthquake

    NASA Astrophysics Data System (ADS)

    Jibson, Randall W.

    Following the 17 January 1994 Northridge, California earthquake (M = 6.7), Ventura County, California, experienced a major outbreak ofcoccidioidomycosis (CM), commonly known as valley fever, a respiratory disease contracted byinhaling airborne fungal spores. In the 8 weeks following the earthquake (24 Januarythrough 15 March), 203 outbreak-associated cases were reported, which is about an order of magnitude more than the expected number of cases, and three of these cases were fatal.Simi Valley, in easternmost Ventura County, had the highest attack rate in the county,and the attack rate decreased westward across the county. The temporal and spatial distribution of CM cases indicates that the outbreak resulted from inhalation of spore-contaminated dust generated by earthquake-triggered landslides. Canyons North East of Simi Valleyproduced many highly disrupted, dust-generating landslides during the earthquake andits aftershocks. Winds after the earthquake were from the North East, which transporteddust into Simi Valley and beyond to communities to the West. The three fatalities from the CM epidemic accounted for 4 percent of the total earthquake-related fatalities.

  5. Keeping the History in Historical Seismology: The 1872 Owens Valley, California Earthquake

    NASA Astrophysics Data System (ADS)

    Hough, Susan E.

    2008-07-01

    The importance of historical earthquakes is being increasingly recognized. Careful investigations of key pre-instrumental earthquakes can provide critical information and insights for not only seismic hazard assessment but also for earthquake science. In recent years, with the explosive growth in computational sophistication in Earth sciences, researchers have developed increasingly sophisticated methods to analyze macroseismic data quantitatively. These methodological developments can be extremely useful to exploit fully the temporally and spatially rich information source that seismic intensities often represent. For example, the exhaustive and painstaking investigations done by Ambraseys and his colleagues of early Himalayan earthquakes provides information that can be used to map out site response in the Ganges basin. In any investigation of macroseismic data, however, one must stay mindful that intensity values are not data but rather interpretations. The results of any subsequent analysis, regardless of the degree of sophistication of the methodology, will be only as reliable as the interpretations of available accounts—and only as complete as the research done to ferret out, and in many cases translate, these accounts. When intensities are assigned without an appreciation of historical setting and context, seemingly careful subsequent analysis can yield grossly inaccurate results. As a case study, I report here on the results of a recent investigation of the 1872 Owen's Valley, California earthquake. Careful consideration of macroseismic observations reveals that this event was probably larger than the great San Francisco earthquake of 1906, and possibly the largest historical earthquake in California. The results suggest that some large earthquakes in California will generate significantly larger ground motions than San Andreas fault events of comparable magnitude.

  6. Keeping the History in Historical Seismology: The 1872 Owens Valley, California Earthquake

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hough, Susan E.

    2008-07-08

    The importance of historical earthquakes is being increasingly recognized. Careful investigations of key pre-instrumental earthquakes can provide critical information and insights for not only seismic hazard assessment but also for earthquake science. In recent years, with the explosive growth in computational sophistication in Earth sciences, researchers have developed increasingly sophisticated methods to analyze macroseismic data quantitatively. These methodological developments can be extremely useful to exploit fully the temporally and spatially rich information source that seismic intensities often represent. For example, the exhaustive and painstaking investigations done by Ambraseys and his colleagues of early Himalayan earthquakes provides information that can bemore » used to map out site response in the Ganges basin. In any investigation of macroseismic data, however, one must stay mindful that intensity values are not data but rather interpretations. The results of any subsequent analysis, regardless of the degree of sophistication of the methodology, will be only as reliable as the interpretations of available accounts - and only as complete as the research done to ferret out, and in many cases translate, these accounts. When intensities are assigned without an appreciation of historical setting and context, seemingly careful subsequent analysis can yield grossly inaccurate results. As a case study, I report here on the results of a recent investigation of the 1872 Owen's Valley, California earthquake. Careful consideration of macroseismic observations reveals that this event was probably larger than the great San Francisco earthquake of 1906, and possibly the largest historical earthquake in California. The results suggest that some large earthquakes in California will generate significantly larger ground motions than San Andreas fault events of comparable magnitude.« less

  7. CRUSTAL REFRACTION PROFILE OF THE LONG VALLEY CALDERA, CALIFORNIA, FROM THE JANUARY 1983 MAMMOTH LAKES EARTHQUAKE SWARM.

    USGS Publications Warehouse

    Luetgert, James H.; Mooney, Walter D.

    1985-01-01

    Seismic-refraction profiles recorded north of Mammoth Lakes, California, using earthquake sources from the January 1983 swarm complement earlier explosion refraction profiles and provide velocity information from deeper in the crust in the area of the Long Valley caldera. Eight earthquakes from a depth range of 4. 9 to 8. 0 km confirm the observation of basement rocks with seismic velocities ranging from 5. 8 to 6. 4 km/sec extending at least to depths of 20 km. The data provide further evidence for the existence of a partial melt zone beneath Long Valley caldera and constrain its geometry. Refs.

  8. Long Period Earthquakes Beneath California's Young and Restless Volcanoes

    NASA Astrophysics Data System (ADS)

    Pitt, A. M.; Dawson, P. B.; Shelly, D. R.; Hill, D. P.; Mangan, M.

    2013-12-01

    The newly established USGS California Volcano Observatory has the broad responsibility of monitoring and assessing hazards at California's potentially threatening volcanoes, most notably Mount Shasta, Medicine Lake, Clear Lake Volcanic Field, and Lassen Volcanic Center in northern California; and Long Valley Caldera, Mammoth Mountain, and Mono-Inyo Craters in east-central California. Volcanic eruptions occur in California about as frequently as the largest San Andreas Fault Zone earthquakes-more than ten eruptions have occurred in the last 1,000 years, most recently at Lassen Peak (1666 C.E. and 1914-1917 C.E.) and Mono-Inyo Craters (c. 1700 C.E.). The Long Valley region (Long Valley caldera and Mammoth Mountain) underwent several episodes of heightened unrest over the last three decades, including intense swarms of volcano-tectonic (VT) earthquakes, rapid caldera uplift, and hazardous CO2 emissions. Both Medicine Lake and Lassen are subsiding at appreciable rates, and along with Clear Lake, Long Valley Caldera, and Mammoth Mountain, sporadically experience long period (LP) earthquakes related to migration of magmatic or hydrothermal fluids. Worldwide, the last two decades have shown the importance of tracking LP earthquakes beneath young volcanic systems, as they often provide indication of impending unrest or eruption. Herein we document the occurrence of LP earthquakes at several of California's young volcanoes, updating a previous study published in Pitt et al., 2002, SRL. All events were detected and located using data from stations within the Northern California Seismic Network (NCSN). Event detection was spatially and temporally uneven across the NCSN in the 1980s and 1990s, but additional stations, adoption of the Earthworm processing system, and heightened vigilance by seismologists have improved the catalog over the last decade. LP earthquakes are now relatively well-recorded under Lassen (~150 events since 2000), Clear Lake (~60 events), Mammoth Mountain

  9. Water-level changes induced by local and distant earthquakes at Long Valley caldera, California

    USGS Publications Warehouse

    Roeloffs, Evelyn A.; Sneed, Michelle; Galloway, Devin L.; Sorey, Michael L.; Farrar, Christopher D.; Howle, James F.; Hughes, J.

    2003-01-01

    Distant as well as local earthquakes have induced groundwater-level changes persisting for days to weeks at Long Valley caldera, California. Four wells open to formations as deep as 300 m have responded to 16 earthquakes, and responses to two earthquakes in the 3-km-deep Long Valley Exploratory Well (LVEW) show that these changes are not limited to weathered or unconsolidated near-surface rocks. All five wells exhibit water-level variations in response to earth tides, indicating they can be used as low-resolution strainmeters. Earthquakes induce gradual water-level changes that increase in amplitude for as long as 30 days, then return more slowly to pre-earthquake levels. The gradual water-level changes are always drops at wells LKT, LVEW, and CH-10B, and always rises at well CW-3. At a dilatometer just outside the caldera, earthquake-induced strain responses consist of either a step followed by a contractional strain-rate increase, or a transient contractional signal that reaches a maximum in about seven days and then returns toward the pre-earthquake value. The sizes of the gradual water-level changes generally increase with earthquake magnitude and decrease with hypocentral distance. Local earthquakes in Long Valley produce coseismic water-level steps; otherwise the responses to local earthquakes and distant earthquakes are indistinguishable. In particular, water-level and strain changes in Long Valley following the 1992 M7.3 Landers earthquake, 450 km distant, closely resemble those initiated by a M4.9 local earthquake on November 22, 1997, during a seismic swarm with features indicative of fluid involvement. At the LKT well, many of the response time histories are identical for 20 days after each earthquake, and can be matched by a theoretical solution giving the pore pressure as a function of time due to diffusion of a nearby, instantaneous, pressure drop. Such pressure drops could be produced by accelerated inflation of the resurgent dome by amounts too

  10. California's restless giant: the Long Valley Caldera

    USGS Publications Warehouse

    Hill, David P.; Bailey, Roy A.; Hendley, James W.; Stauffer, Peter H.; Marcaida, Mae

    2014-01-01

    Scientists have monitored geologic unrest in the Long Valley, California, area since 1980. In that year, following a swarm of strong earthquakes, they discovered that the central part of the Long Valley Caldera had begun actively rising. Unrest in the area persists today. The U.S. Geological Survey (USGS) continues to provide the public and civil authorities with current information on the volcanic hazard at Long Valley and is prepared to give timely warnings of any impending eruption.

  11. GPS measurements of strain accumulation across the Imperial Valley, California: 1986-1989

    NASA Technical Reports Server (NTRS)

    Larsen, Shawn; Reilinger, Robert

    1989-01-01

    The Global Positioning System (GPS) data collected in southern California from 1986 to 1989 indicate considerable strain accumulation across the Imperial Valley. Displacements are computed at 29 stations in and near the valley from 1986 to 1988, and at 11 sites from 1988 to 1989. The earlier measurements indicate 5.9 +/- 1.0 cm/yr right-lateral differential velocity across the valley, although the data are heavily influenced by the 1987 Superstition Hills earthquake sequence. Some measurements, especially the east-trending displacements, are suspects for large errors. The 1988 to 1989 GPS displacements are best modeled by 5.2 +/- 0.9 cm/yr of valley crossing deformation, but rates calculated from conventional geodetic measurements (3.4 to 4.3 cm/yr) fit the data nearly as well. There is evidence from GPS and Very Long Base Interferometry (VLBI) observations that the present slip rate along the southern San Andreas fault is smaller than the long-term geologic estimate, suggesting a lower earthquake potential than is currently assumed. Correspondingly, a higher earthquake potential is indicated for the San Jacinto fault. The Imperial Valley GPS sites form part of a 183 station network in southern California and northern Baja California, which spans a cross-section of the North American-Pacific plate boundary.

  12. Scenario earthquake hazards for the Long Valley Caldera-Mono Lake area, east-central California (ver. 2.0, January 2018)

    USGS Publications Warehouse

    Chen, Rui; Branum, David M.; Wills, Chris J.; Hill, David P.

    2014-06-30

    As part of the U.S. Geological Survey’s (USGS) multi-hazards project in the Long Valley Caldera-Mono Lake area, the California Geological Survey (CGS) developed several earthquake scenarios and evaluated potential seismic hazards, including ground shaking, surface fault rupture, liquefaction, and landslide hazards associated with these earthquake scenarios. The results of these analyses can be useful in estimating the extent of potential damage and economic losses because of potential earthquakes and also for preparing emergency response plans.The Long Valley Caldera-Mono Lake area has numerous active faults. Five of these faults or fault zones are considered capable of producing magnitude ≥6.7 earthquakes according to the Uniform California Earthquake Rupture Forecast, Version 2 (UCERF 2) developed by the 2007 Working Group on California Earthquake Probabilities (WGCEP) and the USGS National Seismic Hazard Mapping Program. These five faults are the Fish Slough, Hartley Springs, Hilton Creek, Mono Lake, and Round Valley Faults. CGS developed earthquake scenarios for these five faults in the study area and for the White Mountains Fault Zone to the east of the study area.In this report, an earthquake scenario is intended to depict the potential consequences of significant earthquakes. A scenario earthquake is not necessarily the largest or most damaging earthquake possible on a recognized fault. Rather it is both large enough and likely enough that emergency planners should consider it in regional emergency response plans. In particular, the ground motion predicted for a given scenario earthquake does not represent a full probabilistic hazard assessment, and thus it does not provide the basis for hazard zoning and earthquake-resistant building design.Earthquake scenarios presented here are based on fault geometry and activity data developed by the WGCEP, and are consistent with the 2008 Update of the United States National Seismic Hazard Maps (NSHM). Alternatives

  13. Late Quaternary history of the Owens Valley fault zone, eastern California, and surface rupture associated with the 1872 earthquake

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Beanland, S.; Clark, M.M.

    1993-04-01

    The right-lateral Owens Valley fault zone (OVFZ) in eastern California extends north about 100 km from near the northwest shore of Owens Lake to beyond Big Pine. It passes through Lone Pine near the eastern base of the Alabama Hills and follows the floor of Owens Valley northward to the Poverty Hills, where it steps 3 km to the left and continues northwest across Crater Mountain and through Big Pine. Data from one site suggest an average net slip rate for the OVFZ of 1.5 [+-] 1 mm/yr for the past 300 ky. Several other sites yield an average Holocenemore » net slip rate of 2 [+-] 1 mm/yr. The OVFZ apparently has experienced three major Holocene earthquakes. The minimum average recurrence interval is 5,000 years at the subsidiary Lone Pine fault, whereas it is 3,300 to 5,000 years elsewhere along the OVFZ. The prehistoric earthquakes are not dated, so an average recurrence interval need not apply. However, roughly equal (characteristic) displacement apparently happened during each Holocene earthquake. The Owens Valley fault zone accommodates some of the relative motion (dextral shear) between the North American and Pacific plates along a discrete structure. This shear occurs in the Walker Lane belt of normal and strike-slip faults within the mainly extensional Basin and Range Province. In Owens Valley displacement is partitioned between the OVFZ and the nearby, subparallel, and purely normal range-front faults of the Sierra Nevada. Compared to the OVFZ, these range-front normal faults are very discontinuous and have smaller Holocene slip rates of 0.1 to 0.8 mm/yr, dip slip. Contemporary activity on adjacent faults of such contrasting styles suggests large temporal fluctuations in the relative magnitudes of the maximum and intermediate principal stresses while the extension direction remains consistently east-west.« less

  14. Distribution of intensity for the Westmorland, California, earthquake of April 26, 1981

    USGS Publications Warehouse

    Barnhard, L.M.; Thenhaus, P.C.; Algermissen, Sylvester Theodore

    1982-01-01

    The maximum Modified Mercalli intensity of the April 26, 1981 earthquake located 5 km northwest of Westmorland, California is VII. Twelve buildings in Westmorland were severely damaged with an additional 30 sustaining minor damage. Two brick parapets fell in Calipatria, 14 km northeast of Westmorland and 10 km from the earthquake epicenter. Significant damage in rural areas was restricted to unreinforced, concrete-lined irrigation canals. Liquefaction effects and ground slumping were widespread in rural areas and were the primary causes of road cracking. Preliminary local government estimates of property loss range from one to three million dollars (Imperial Valley Press, 1981). The earthquake was felt over an area of approximately 160,000 km2; about the same felt area of the October 15, 1979 (Reagor and others, 1980), and May 18, 1940 (Ulrich, 1941) Imperial Valley earthquakes.

  15. Surface slip during large Owens Valley earthquakes

    NASA Astrophysics Data System (ADS)

    Haddon, E. K.; Amos, C. B.; Zielke, O.; Jayko, A. S.; Bürgmann, R.

    2016-06-01

    The 1872 Owens Valley earthquake is the third largest known historical earthquake in California. Relatively sparse field data and a complex rupture trace, however, inhibited attempts to fully resolve the slip distribution and reconcile the total moment release. We present a new, comprehensive record of surface slip based on lidar and field investigation, documenting 162 new measurements of laterally and vertically displaced landforms for 1872 and prehistoric Owens Valley earthquakes. Our lidar analysis uses a newly developed analytical tool to measure fault slip based on cross-correlation of sublinear topographic features and to produce a uniquely shaped probability density function (PDF) for each measurement. Stacking PDFs along strike to form cumulative offset probability distribution plots (COPDs) highlights common values corresponding to single and multiple-event displacements. Lateral offsets for 1872 vary systematically from ˜1.0 to 6.0 m and average 3.3 ± 1.1 m (2σ). Vertical offsets are predominantly east-down between ˜0.1 and 2.4 m, with a mean of 0.8 ± 0.5 m. The average lateral-to-vertical ratio compiled at specific sites is ˜6:1. Summing displacements across subparallel, overlapping rupture traces implies a maximum of 7-11 m and net average of 4.4 ± 1.5 m, corresponding to a geologic Mw ˜7.5 for the 1872 event. We attribute progressively higher-offset lateral COPD peaks at 7.1 ± 2.0 m, 12.8 ± 1.5 m, and 16.6 ± 1.4 m to three earlier large surface ruptures. Evaluating cumulative displacements in context with previously dated landforms in Owens Valley suggests relatively modest rates of fault slip, averaging between ˜0.6 and 1.6 mm/yr (1σ) over the late Quaternary.

  16. Surface slip during large Owens Valley earthquakes

    USGS Publications Warehouse

    Haddon, E.K.; Amos, C.B.; Zielke, O.; Jayko, Angela S.; Burgmann, R.

    2016-01-01

    The 1872 Owens Valley earthquake is the third largest known historical earthquake in California. Relatively sparse field data and a complex rupture trace, however, inhibited attempts to fully resolve the slip distribution and reconcile the total moment release. We present a new, comprehensive record of surface slip based on lidar and field investigation, documenting 162 new measurements of laterally and vertically displaced landforms for 1872 and prehistoric Owens Valley earthquakes. Our lidar analysis uses a newly developed analytical tool to measure fault slip based on cross-correlation of sublinear topographic features and to produce a uniquely shaped probability density function (PDF) for each measurement. Stacking PDFs along strike to form cumulative offset probability distribution plots (COPDs) highlights common values corresponding to single and multiple-event displacements. Lateral offsets for 1872 vary systematically from ∼1.0 to 6.0 m and average 3.3 ± 1.1 m (2σ). Vertical offsets are predominantly east-down between ∼0.1 and 2.4 m, with a mean of 0.8 ± 0.5 m. The average lateral-to-vertical ratio compiled at specific sites is ∼6:1. Summing displacements across subparallel, overlapping rupture traces implies a maximum of 7–11 m and net average of 4.4 ± 1.5 m, corresponding to a geologic Mw ∼7.5 for the 1872 event. We attribute progressively higher-offset lateral COPD peaks at 7.1 ± 2.0 m, 12.8 ± 1.5 m, and 16.6 ± 1.4 m to three earlier large surface ruptures. Evaluating cumulative displacements in context with previously dated landforms in Owens Valley suggests relatively modest rates of fault slip, averaging between ∼0.6 and 1.6 mm/yr (1σ) over the late Quaternary.

  17. Instability model for recurring large and great earthquakes in southern California

    USGS Publications Warehouse

    Stuart, W.D.

    1985-01-01

    The locked section of the San Andreas fault in southern California has experienced a number of large and great earthquakes in the past, and thus is expected to have more in the future. To estimate the location, time, and slip of the next few earthquakes, an earthquake instability model is formulated. The model is similar to one recently developed for moderate earthquakes on the San Andreas fault near Parkfield, California. In both models, unstable faulting (the earthquake analog) is caused by failure of all or part of a patch of brittle, strain-softening fault zone. In the present model the patch extends downward from the ground surface to about 12 km depth, and extends 500 km along strike from Parkfield to the Salton Sea. The variation of patch strength along strike is adjusted by trial until the computed sequence of instabilities matches the sequence of large and great earthquakes since a.d. 1080 reported by Sieh and others. The last earthquake was the M=8.3 Ft. Tejon event in 1857. The resulting strength variation has five contiguous sections of alternately low and high strength. From north to south, the approximate locations of the sections are: (1) Parkfield to Bitterwater Valley, (2) Bitterwater Valley to Lake Hughes, (3) Lake Hughes to San Bernardino, (4) San Bernardino to Palm Springs, and (5) Palm Springs to the Salton Sea. Sections 1, 3, and 5 have strengths between 53 and 88 bars; sections 2 and 4 have strengths between 164 and 193 bars. Patch section ends and unstable rupture ends usually coincide, although one or more adjacent patch sections may fail unstably at once. The model predicts that the next sections of the fault to slip unstably will be 1, 3, and 5; the order and dates depend on the assumed length of an earthquake rupture in about 1700. ?? 1985 Birkha??user Verlag.

  18. Breaks in Pavement and Pipes as Indicators of Range-Front Faulting Resulting from the 1989 Loma Prieta Earthquake near the Southwest Margin of the Santa Clara Valley, California

    USGS Publications Warehouse

    Schmidt, Kevin M.; Ellen, Stephen D.; Haugerud, Ralph A.; Peterson, David M.; Phelps, Geoffery A.

    1995-01-01

    Damage to pavement and near-surface utility pipes, caused by the October 17, 1989, Loma Prieta earthquake, provide indicators for ground deformation in a 663 km2 area near the southwest margin of the Santa Clara Valley, California. The spatial distribution of 1284 sites of such damage documents the extent and distribution of detectable ground deformation. Damage was concentrated in four zones, three of which are near previously mapped faults. The zone through Los Gatos showed the highest concentration of damage, as well as evidence for pre- and post-earthquake deformation. Damage along the foot of the Santa Cruz Mountains reflected shortening that is consistent with movement along reverse faults in the region and with the hypothesis that tectonic strain is distributed widely across numerous faults in the California Coast Ranges.

  19. High-resolution seismic reflection/refraction imaging from Interstate 10 to Cherry Valley Boulevard, Cherry Valley, Riverside County, California: implications for water resources and earthquake hazards

    USGS Publications Warehouse

    Gandhok, G.; Catchings, R.D.; Goldman, M.R.; Horta, E.; Rymer, M.J.; Martin, P.; Christensen, A.

    1999-01-01

    This report is the second of two reports on seismic imaging investigations conducted by the U.S. Geological Survey (USGS) during the summers of 1997 and 1998 in the Cherry Valley area in California (Figure 1a). In the first report (Catchings et al., 1999), data and interpretations were presented for four seismic imaging profiles (CV-1, CV-2, CV-3, and CV-4) acquired during the summer of 1997 . In this report, we present data and interpretations for three additional profiles (CV-5, CV-6, and CV-7) acquired during the summer of 1998 and the combined seismic images for all seven profiles. This report addresses both groundwater resources and earthquake hazards in the San Gorgonio Pass area because the shallow (upper few hundred meters) subsurface stratigraphy and structure affect both issues. The cities of Cherry Valley and Beaumont are located approximately 130 km (~80 miles) east of Los Angeles, California along the southern alluvial fan of the San Bernardino Mountains (see Figure 1b). These cities are two of several small cities that are located within San Gorgonio Pass, a lower-lying area between the San Bernardino and the San Jacinto Mountains. Cherry Valley and Beaumont are desert cities with summer daytime temperatures often well above 100 o F. High water usage in the arid climate taxes the available groundwater supply in the region, increasing the need for efficient management of the groundwater resources. The USGS and the San Gorgonio Water District (SGWD) work cooperatively to evaluate the quantity and quality of groundwater supply in the San Gorgonio Pass region. To better manage the water supplies within the District during wet and dry periods, the SGWD sought to develop a groundwater recharge program, whereby, excess water would be stored in underground aquifers during wet periods (principally winter months) and retrieved during dry periods (principally summer months). The SGWD preferred a surface recharge approach because it could be less expensive than a

  20. Catalog of earthquakes along the San Andreas fault system in Central California: January-March, 1972

    USGS Publications Warehouse

    Wesson, R.L.; Bennett, R.E.; Meagher, K.L.

    1973-01-01

    Numerous small earthquakes occur each day in the Coast Ranges of Central California. The detailed study of these earthquakes provides a tool for gaining insight into the tectonic and physical processes responsible for the generation of damaging earthquakes. This catalog contains the fundamental parameters for earthquakes located within and adjacent to the seismograph network operated by the National Center for Earthquake Research (NCER), U.S. Geological Survey, during the period January - March, 1972. The motivation for these detailed studies has been described by Pakiser and others (1969) and by Eaton and others (1970). Similar catalogs of earthquakes for the years 1969, 1970 and 1971 have been prepared by Lee and others (1972 b,c,d). The basic data contained in these catalogs provide a foundation for further studies. This catalog contains data on 1,718 earthquakes in Central California. Of particular interest is a sequence of earthquakes in the Bear Valley area which contained single shocks with local magnitudes of S.O and 4.6. Earthquakes from this sequence make up roughly 66% of the total and are currently the subject of an interpretative study. Arrival times at 118 seismograph stations were used to locate the earthquakes listed in this catalog. Of these, 94 are telemetered stations operated by NCER. Readings from the remaining 24 stations were obtained through the courtesy of the Seismographic Stations, University of California, Berkeley (UCB); the Earthquake Mechanism Laboratory, National Oceanic and Atmospheric Administration, San Francisco (EML); and the California Department of Water Resources, Sacramento. The Seismographic Stations of the University of California, Berkeley,have for many years published a bulletin describing earthquakes in Northern California and the surrounding area, and readings at UCB Stations from more distant events. The purpose of the present catalog is not to replace the UCB Bulletin, but rather to supplement it, by describing the

  1. Catalog of earthquakes along the San Andreas fault system in Central California, April-June 1972

    USGS Publications Warehouse

    Wesson, R.L.; Bennett, R.E.; Lester, F.W.

    1973-01-01

    Numerous small earthquakes occur each day in the coast ranges of Central California. The detailed study of these earthquakes provides a tool for gaining insight into the tectonic and physical processes responsible for the generation of damaging earthquakes. This catalog contains the fundamental parameters for earthquakes located within and adjacent to the seismograph network operated by the National Center for Earthquake Research (NCER), U.S. Geological Survey, during the period April - June, 1972. The motivation for these detailed studies has been described by Pakiser and others (1969) and by Eaton and others (1970). Similar catalogs of earthquakes for the years 1969, 1970 and 1971 have been prepared by Lee and others (1972 b, c, d). A catalog for the first quarter of 1972 has been prepared by Wesson and others (1972). The basic data contained in these catalogs provide a foundation for further studies. This catalog contains data on 910 earthquakes in Central California. A substantial portion of the earthquakes reported in this catalog represents a continuation of the sequence of earthquakes in the Bear Valley area which began in February, 1972 (Wesson and others, 1972). Arrival times at 126 seismograph stations were used to locate the earthquakes listed in this catalog. Of these, 101 are telemetered stations operated by NCER. Readings from the remaining 25 stations were obtained through the courtesy of the Seismographic Stations, University of California, Berkeley (UCB); the Earthquake Mechanism Laboratory, National Oceanic and Atmospheric Administration, San Francisco (EML); and the California Department of Water Resources, Sacramento. The Seismographic Stations of the University of California, Berkeley, have for many years published a bulletin describing earthquakes in Northern California and the surrounding area, and readings at UCB Stations from more distant events. The purpose of the present catalog is not to replace the UCB Bulletin, but rather to supplement

  2. Geophysical setting of the 2000 ML 5.2 Yountville, California, earthquake: Implications for seismic Hazard in Napa Valley, California

    USGS Publications Warehouse

    Langenheim, V.E.; Graymer, R.W.; Jachens, R.C.

    2006-01-01

    The epicenter of the 2000 ML 5.2 Yountville earthquake was located 5 km west of the surface trace of the West Napa fault, as defined by Helley and Herd (1977). On the basis of the re-examination of geologic data and the analysis of potential field data, the earthquake occurred on a strand of the West Napa fault, the main basin-bounding fault along the west side of Napa Valley. Linear aeromagnetic anomalies and a prominent gravity gradient extend the length of the fault to the latitude of Calistoga, suggesting that this fault may be capable of larger-magnitude earthquakes. Gravity data indicate an ???2-km-deep basin centered on the town of Napa, where damage was concentrated during the Yountville earthquake. It most likely played a minor role in enhancing shaking during this event but may lead to enhanced shaking caused by wave trapping during a larger-magnitude earthquake.

  3. Earthquake swarms and local crustal spreading along major strike-slip faults in California

    USGS Publications Warehouse

    Weaver, C.S.; Hill, D.P.

    1978-01-01

    Earthquake swarms in California are often localized to areas within dextral offsets in the linear trend in active fault strands, suggesting a relation between earthquake swarms and local crustal spreading. Local crustal spereading is required by the geometry of dextral offsets when, as in the San Andreas system, faults have dominantly strike-slip motion with right-lateral displacement. Three clear examples of this relation occur in the Imperial Valley, Coso Hot Springs, and the Danville region, all in California. The first two of these areas are known for their Holocene volcanism and geothermal potential, which is consistent with crustal spreading and magmatic intrusion. The third example, however, shows no evidence for volcanism or geothermal activity at the surface. ?? 1978 Birkha??user Verlag.

  4. Structure and Velocities of the Northeastern Santa Cruz Mountains and the Western Santa Clara Valley, California, from the SCSI-LR Seismic Survey

    USGS Publications Warehouse

    Catchings, R.D.; Goldman, M.R.; Gandhok, G.

    2006-01-01

    Introduction: The Santa Clara Valley is located in the southern San Francisco Bay area of California and generally includes the area south of the San Francisco Bay between the Santa Cruz Mountains on the southwest and the Diablo Ranges on the northeast. The area has a population of approximately 1.7 million including the city of San Jose, numerous smaller cities, and much of the high-technology manufacturing and research area commonly referred to as the Silicon Valley. Major active strands of the San Andreas Fault system bound the Santa Clara Valley, including the San Andreas fault to the southwest and the Hayward and Calaveras faults to the northeast; related faults likely underlie the alluvium of the valley. This report focuses on subsurface structures of the western Santa Clara Valley and the northeastern Santa Cruz Mountains and their potential effects on earthquake hazards and ground-water resource management in the area. Earthquake hazards and ground-water resources in the Santa Clara Valley are important considerations to California and the Nation because of the valley's preeminence as a major technical and industrial center, proximity to major earthquakes faults, and large population. To assess the earthquake hazards of the Santa Clara Valley better, the U.S. Geological Survey (USGS) has undertaken a program to evaluate potential earthquake sources and potential effects of strong ground shaking within the valley. As part of that program, and to better assess water resources of the valley, the USGS and the Santa Clara Valley Water District (SCVWD) began conducting collaborative studies to characterize the faults, stratigraphy, and structures beneath the alluvial cover of the Santa Clara Valley in the year 2000. Such geologic features are important to both agencies because they directly influence the availability and management of groundwater resources in the valley, and they affect the severity and distribution of strong shaking from local or regional

  5. Next-Day Earthquake Forecasts for California

    NASA Astrophysics Data System (ADS)

    Werner, M. J.; Jackson, D. D.; Kagan, Y. Y.

    2008-12-01

    We implemented a daily forecast of m > 4 earthquakes for California in the format suitable for testing in community-based earthquake predictability experiments: Regional Earthquake Likelihood Models (RELM) and the Collaboratory for the Study of Earthquake Predictability (CSEP). The forecast is based on near-real time earthquake reports from the ANSS catalog above magnitude 2 and will be available online. The model used to generate the forecasts is based on the Epidemic-Type Earthquake Sequence (ETES) model, a stochastic model of clustered and triggered seismicity. Our particular implementation is based on the earlier work of Helmstetter et al. (2006, 2007), but we extended the forecast to all of Cali-fornia, use more data to calibrate the model and its parameters, and made some modifications. Our forecasts will compete against the Short-Term Earthquake Probabilities (STEP) forecasts of Gersten-berger et al. (2005) and other models in the next-day testing class of the CSEP experiment in California. We illustrate our forecasts with examples and discuss preliminary results.

  6. The Pocatello Valley, Idaho, earthquake

    USGS Publications Warehouse

    Rogers, A. M.; Langer, C.J.; Bucknam, R.C.

    1975-01-01

    A Richter magnitude 6.3 earthquake occurred at 8:31 p.m mountain daylight time on March 27, 1975, near the Utah-Idaho border in Pocatello Valley. The epicenter of the main shock was located at 42.094° N, 112.478° W, and had a focal depth of 5.5 km. This earthquake was the largest in the continental United States since the destructive San Fernando earthquake of February 1971. The main shock was preceded by a magnitude 4.5 foreshock on March 26. 

  7. Aftershocks and triggered events of the Great 1906 California earthquake

    USGS Publications Warehouse

    Meltzner, A.J.; Wald, D.J.

    2003-01-01

    The San Andreas fault is the longest fault in California and one of the longest strike-slip faults in the world, yet little is known about the aftershocks following the most recent great event on the San Andreas, the Mw 7.8 San Francisco earthquake on 18 April 1906. We conducted a study to locate and to estimate magnitudes for the largest aftershocks and triggered events of this earthquake. We examined existing catalogs and historical documents for the period April 1906 to December 1907, compiling data on the first 20 months of the aftershock sequence. We grouped felt reports temporally and assigned modified Mercalli intensities for the larger events based on the descriptions judged to be the most reliable. For onshore and near-shore events, a grid-search algorithm (derived from empirical analysis of modern earthquakes) was used to find the epicentral location and magnitude most consistent with the assigned intensities. For one event identified as far offshore, the event's intensity distribution was compared with those of modern events, in order to contrain the event's location and magnitude. The largest aftershock within the study period, an M ???6.7 event, occurred ???100 km west of Eureka on 23 April 1906. Although not within our study period, another M ???6.7 aftershock occurred near Cape Mendocino on 28 October 1909. Other significant aftershocks included an M ???5.6 event near San Juan Bautista on 17 May 1906 and an M ???6.3 event near Shelter Cove on 11 August 1907. An M ???4.9 aftershock occurred on the creeping segment of the San Andreas fault (southeast of the mainshock rupture) on 6 July 1906. The 1906 San Francisco earthquake also triggered events in southern California (including separate events in or near the Imperial Valley, the Pomona Valley, and Santa Monica Bay), in western Nevada, in southern central Oregon, and in western Arizona, all within 2 days of the mainshock. Of these trigerred events, the largest were an M ???6.1 earthquake near Brawley

  8. The California Earthquake Advisory Plan: A history

    USGS Publications Warehouse

    Roeloffs, Evelyn A.; Goltz, James D.

    2017-01-01

    Since 1985, the California Office of Emergency Services (Cal OES) has issued advisory statements to local jurisdictions and the public following seismic activity that scientists on the California Earthquake Prediction Evaluation Council view as indicating elevated probability of a larger earthquake in the same area during the next several days. These advisory statements are motivated by statistical studies showing that about 5% of moderate earthquakes in California are followed by larger events within a 10-km, five-day space-time window (Jones, 1985; Agnew and Jones, 1991; Reasenberg and Jones, 1994). Cal OES issued four earthquake advisories from 1985 to 1989. In October, 1990, the California Earthquake Advisory Plan formalized this practice, and six Cal OES Advisories have been issued since then. This article describes that protocol’s scientific basis and evolution.

  9. Earthquake education in California

    USGS Publications Warehouse

    MacCabe, M. P.

    1980-01-01

    In a survey of community response to the earthquake threat in southern California, Ralph Turner and his colleagues in the Department of Sociology at the University of California, Los Angeles, found that the public very definitely wants to be educated about the kinds of problems and hazards they can expect during and after a damaging earthquake; and they also want to know how they can prepare themselves to minimize their vulnerability. Decisionmakers, too, are recognizing this new wave of public concern. 

  10. Accessing northern California earthquake data via Internet

    NASA Astrophysics Data System (ADS)

    Romanowicz, Barbara; Neuhauser, Douglas; Bogaert, Barbara; Oppenheimer, David

    The Northern California Earthquake Data Center (NCEDC) provides easy access to central and northern California digital earthquake data. It is located at the University of California, Berkeley, and is operated jointly with the U.S. Geological Survey (USGS) in Menlo Park, Calif., and funded by the University of California and the National Earthquake Hazard Reduction Program. It has been accessible to users in the scientific community through Internet since mid-1992.The data center provides an on-line archive for parametric and waveform data from two regional networks: the Northern California Seismic Network (NCSN) operated by the USGS and the Berkeley Digital Seismic Network (BDSN) operated by the Seismographic Station at the University of California, Berkeley.

  11. WGCEP Historical California Earthquake Catalog

    USGS Publications Warehouse

    Felzer, Karen R.; Cao, Tianqing

    2008-01-01

    This appendix provides an earthquake catalog for California and the surrounding area. Our goal is to provide a listing for all known M > 5.5 earthquakes that occurred from 1850-1932 and all known M > 4.0 earthquakes that occurred from 1932-2006 within the region of 31.0 to 43.0 degrees North and -126.0 to -114.0 degrees West. Some pre-1932 earthquakes 4 5, before the Northern California network was online. Some earthquakes from 1900-1932, and particularly from 1910-1932 are also based on instrumental readings, but the quality of the instrumental record and the resulting analysis are much less precise than for later listings. A partial exception is for some of the largest earthquakes, such as the San Francisco earthquake of April 18, 1906, for which global teleseismic records (Wald et al. 1993) and geodetic measurements (Thatcher et al. 1906) have been used to help determine magnitudes.

  12. A Crustal Velocity Model for South Mexicali Valley, Baja California, México.

    NASA Astrophysics Data System (ADS)

    Ramirez, E.; Vidal-Villegas, A.; Stock, J. M.; Gonzalez-Fernandez, A.

    2016-12-01

    The northern Baja California region consists of two subregions of different geological features: the Peninsular Ranges of Baja California, of granitic composition, and the Mexicali Valley region, characterized by a series of sedimentary basins: the Laguna Salada and the Mexicali Valley. Due to the lack of an appropriate crust model for South Mexicali Valley, a refraction study was conducted. We installed 16 three-component short period stations (2 Hz) and one broadband station (100 s - 50 Hz). The stations, spaced 6 km along a refraction profile, recorded a blast performed in the southwest Arizona near the border with Sonora, Mexico. Records gathered were used to estimate a crust velocity structure model for South Mexicali Valley. The beginning of the profile is at San Luis Rio Colorado (SLRC), Sonora and its ending is at the middle of Sierra Juarez, Baja California. As a "reverse shot", for a 47 km section between SLRC and El Mayor Mountain, we used an aftershock M 3.4 of the 2010 M 7.2 El Mayor - Cucapah earthquake. Record sections show seismograms with impulsive P arrivals for nearby stations. The arrival Pn wave is observed at three stations located in Laguna Salada and Sierra Juarez. From the first arrivals of refractions and reflections of the P wave we performed direct modeling of travel times and relative amplitudes (normalized synthetic seismograms). Method based on asymptotic ray theory programed in the RAYINVR software (Zelt and Smith, 1992). We propose an average-three-layer velocity structure model: 2.9, 5.6 and 6.9 km/s, with thicknesses of 1.2, 4.4 and 9.6 km, respectively. Velocities of our model for the region under study are about 1 km/s higher than the model proposed by McMechan and Mooney (1984) for the Imperial Valley. The preliminary interpretation using the "reverse shot" indicates a crust of 15 km depth beneath the Mexicali Valley and 19 km under the El Mayor Mountain and Laguna Salada basin. On the eastern side of the El Mayor Mountain we

  13. A record of large earthquakes during the past two millennia on the southern Green Valley Fault, California

    USGS Publications Warehouse

    Lienkaemper, James J.; Baldwin, John N.; Turner, Robert; Sickler, Robert R.; Brown, Johnathan

    2013-01-01

    We document evidence for surface-rupturing earthquakes (events) at two trench sites on the southern Green Valley fault, California (SGVF). The 75-80-km long dextral SGVF creeps ~1-4 mm/yr. We identify stratigraphic horizons disrupted by upward-flowering shears and in-filled fissures unlikely to have formed from creep alone. The Mason Rd site exhibits four events from ~1013 CE to the Present. The Lopes Ranch site (LR, 12 km to the south) exhibits three events from 18 BCE to Present including the most recent event (MRE), 1610 ±52 yr CE (1σ) and a two-event interval (18 BCE-238 CE) isolated by a millennium of low deposition. Using Oxcal to model the timing of the 4-event earthquake sequence from radiocarbon data and the LR MRE yields a mean recurrence interval (RI or μ) of 199 ±82 yr (1σ) and ±35 yr (standard error of the mean), the first based on geologic data. The time since the most recent earthquake (open window since MRE) is 402 yr ±52 yr, well past μ~200 yr. The shape of the probability density function (pdf) of the average RI from Oxcal resembles a Brownian Passage Time (BPT) pdf (i.e., rather than normal) that permits rarer longer ruptures potentially involving the Berryessa and Hunting Creek sections of the northernmost GVF. The model coefficient of variation (cv, σ/μ) is 0.41, but a larger value (cv ~0.6) fits better when using BPT. A BPT pdf with μ of 250 yr and cv of 0.6 yields 30-yr rupture probabilities of 20-25% versus a Poisson probability of 11-17%.

  14. Seismicity and stress transfer studies in eastern California and Nevada: Implications for earthquake sources and tectonics

    NASA Astrophysics Data System (ADS)

    Ichinose, Gene Aaron

    The source parameters for eastern California and western Nevada earthquakes are estimated from regionally recorded seismograms using a moment tensor inversion. We use the point source approximation and fit the seismograms, at long periods. We generated a moment tensor catalog for Mw > 4.0 since 1997 and Mw > 5.0 since 1990. The catalog includes centroid depths, seismic moments, and focal mechanisms. The regions with the most moderate sized earthquakes in the last decade were in aftershock zones located in Eureka Valley, Double Spring Flat, Coso, Ridgecrest, Fish Lake Valley, and Scotty's Junction. The remaining moderate size earthquakes were distributed across the region. The 1993 (Mw 6.0) Eureka Valley earthquake occurred in the Eastern California Shear Zone. Careful aftershock relocations were used to resolve structure from aftershock clusters. The mainshock appears to rupture along the western side of the Last Change Range along a 30° to 60° west dipping fault plane, consistent with previous geodetic modeling. We estimate the source parameters for aftershocks at source-receiver distances less than 20 km using waveform modeling. The relocated aftershocks and waveform modeling results do not indicate any significant evidence of low angle faulting (dips > 30°. The results did reveal deformation along vertical faults within the hanging-wall block, consistent with observed surface rupture along the Saline Range above the dipping fault plane. The 1994 (Mw 5.8) Double Spring Flat earthquake occurred along the eastern Sierra Nevada between overlapping normal faults. Aftershock migration and cross fault triggering occurred in the following two years, producing seventeen Mw > 4 aftershocks The source parameters for the largest aftershocks were estimated from regionally recorded seismograms using moment tensor inversion. We estimate the source parameters for two moderate sized earthquakes which occurred near Reno, Nevada, the 1995 (Mw 4.4) Border Town, and the 1998 (Mw

  15. The Uniform California Earthquake Rupture Forecast, Version 2 (UCERF 2)

    USGS Publications Warehouse

    ,

    2008-01-01

    California?s 35 million people live among some of the most active earthquake faults in the United States. Public safety demands credible assessments of the earthquake hazard to maintain appropriate building codes for safe construction and earthquake insurance for loss protection. Seismic hazard analysis begins with an earthquake rupture forecast?a model of probabilities that earthquakes of specified magnitudes, locations, and faulting types will occur during a specified time interval. This report describes a new earthquake rupture forecast for California developed by the 2007 Working Group on California Earthquake Probabilities (WGCEP 2007).

  16. Seasonal Water Storage, the Resulting Deformation and Stress, and Occurrence of Earthquakes in California

    NASA Astrophysics Data System (ADS)

    Johnson, C. W.; Burgmann, R.; Fu, Y.; Dutilleul, P.

    2015-12-01

    In California the accumulated winter snow pack in the Sierra Nevada, reservoirs and groundwater water storage in the Central Valley follow an annual periodic cycle and each contribute to the resulting surface deformation, which can be observed using GPS time series. The ongoing drought conditions in the western U.S. amplify the observed uplift signal as the Earth's crust responds to the mass changes associated with the water loss. The near surface hydrological mass loss can result in annual stress changes of ~1kPa at seismogenic depths. Similarly, small static stress perturbations have previously been associated with changes in earthquake activity. Periodicity analysis of earthquake catalog time series suggest that periods of 4-, 6-, 12-, and 14.24-months are statistically significant in regions of California, and provide documentation for the modulation of earthquake populations at periods of natural loading cycles. Knowledge of what governs the timing of earthquakes is essential to understanding the nature of the earthquake cycle. If small static stress changes influence the timing of earthquakes, then one could expect that events will occur more rapidly during periods of greater external load increases. To test this hypothesis we develop a loading model using GPS derived surface water storage for California and calculate the stress change at seismogenic depths for different faulting geometries. We then evaluate the degree of correlation between the stress models and the seismicity taking into consideration the variable amplitude of stress cycles, the orientation of transient load stress with respect to the background stress field, and the geometry of active faults revealed by focal mechanisms.

  17. Geomorphic legacy of medieval Himalayan earthquakes in the Pokhara Valley

    NASA Astrophysics Data System (ADS)

    Schwanghart, Wolfgang; Bernhardt, Anne; Stolle, Amelie; Hoelzmann, Philipp; Adhikari, Basanta R.; Andermann, Christoff; Tofelde, Stefanie; Merchel, Silke; Rugel, Georg; Fort, Monique; Korup, Oliver

    2016-04-01

    The Himalayas and their foreland belong to the world's most earthquake-prone regions. With millions of people at risk from severe ground shaking and associated damages, reliable data on the spatial and temporal occurrence of past major earthquakes is urgently needed to inform seismic risk analysis. Beyond the instrumental record such information has been largely based on historical accounts and trench studies. Written records provide evidence for damages and fatalities, yet are difficult to interpret when derived from the far-field. Trench studies, in turn, offer information on rupture histories, lengths and displacements along faults but involve high chronological uncertainties and fail to record earthquakes that do not rupture the surface. Thus, additional and independent information is required for developing reliable earthquake histories. Here, we present exceptionally well-dated evidence of catastrophic valley infill in the Pokhara Valley, Nepal. Bayesian calibration of radiocarbon dates from peat beds, plant macrofossils, and humic silts in fine-grained tributary sediments yields a robust age distribution that matches the timing of nearby M>8 earthquakes in ~1100, 1255, and 1344 AD. The upstream dip of tributary valley fills and X-ray fluorescence spectrometry of their provenance rule out local sediment sources. Instead, geomorphic and sedimentary evidence is consistent with catastrophic fluvial aggradation and debris flows that had plugged several tributaries with tens of meters of calcareous sediment from the Annapurna Massif >60 km away. The landscape-changing consequences of past large Himalayan earthquakes have so far been elusive. Catastrophic aggradation in the wake of two historically documented medieval earthquakes and one inferred from trench studies underscores that Himalayan valley fills should be considered as potential archives of past earthquakes. Such valley fills are pervasive in the Lesser Himalaya though high erosion rates reduce

  18. Triggered surface slips in the Coachella Valley area associated with the 1992 Joshua Tree and Landers, California, Earthquakes

    USGS Publications Warehouse

    Rymer, M.J.

    2000-01-01

    The Coachella Valley area was strongly shaken by the 1992 Joshua Tree (23 April) and Landers (28 June) earthquakes, and both events caused triggered slip on active faults within the area. Triggered slip associated with the Joshua Tree earthquake was on a newly recognized fault, the East Wide Canyon fault, near the southwestern edge of the Little San Bernardino Mountains. Slip associated with the Landers earthquake formed along the San Andreas fault in the southeastern Coachella Valley. Surface fractures formed along the East Wide Canyon fault in association with the Joshua Tree earthquake. The fractures extended discontinuously over a 1.5-km stretch of the fault, near its southern end. Sense of slip was consistently right-oblique, west side down, similar to the long-term style of faulting. Measured offset values were small, with right-lateral and vertical components of slip ranging from 1 to 6 mm and 1 to 4 mm, respectively. This is the first documented historic slip on the East Wide Canyon fault, which was first mapped only months before the Joshua Tree earthquake. Surface slip associated with the Joshua Tree earthquake most likely developed as triggered slip given its 5 km distance from the Joshua Tree epicenter and aftershocks. As revealed in a trench investigation, slip formed in an area with only a thin (<3 m thick) veneer of alluvium in contrast to earlier documented triggered slip events in this region, all in the deep basins of the Salton Trough. A paleoseismic trench study in an area of 1992 surface slip revealed evidence of two and possibly three surface faulting events on the East Wide Canyon fault during the late Quaternary, probably latest Pleistocene (first event) and mid- to late Holocene (second two events). About two months after the Joshua Tree earthquake, the Landers earthquake then triggered slip on many faults, including the San Andreas fault in the southeastern Coachella Valley. Surface fractures associated with this event formed discontinuous

  19. Preliminary Analysis of Remote Triggered Seismicity in Northern Baja California Generated by the 2011, Tohoku-Oki, Japan Earthquake

    NASA Astrophysics Data System (ADS)

    Wong-Ortega, V.; Castro, R. R.; Gonzalez-Huizar, H.; Velasco, A. A.

    2013-05-01

    We analyze possible variations of seismicity in the northern Baja California due to the passage of seismic waves from the 2011, M9.0, Tohoku-Oki, Japan earthquake. The northwestern area of Baja California is characterized by a mountain range composed of crystalline rocks. These Peninsular Ranges of Baja California exhibits high microseismic activity and moderate size earthquakes. In the eastern region of Baja California shearing between the Pacific and the North American plates takes place and the Imperial and Cerro-Prieto faults generate most of the seismicity. The seismicity in these regions is monitored by the seismic network RESNOM operated by the Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE). This network consists of 13 three-component seismic stations. We use the seismic catalog of RESNOM to search for changes in local seismic rates occurred after the passing of surface waves generated by the Tohoku-Oki, Japan earthquake. When we compare one month of seismicity before and after the M9.0 earthquake, the preliminary analysis shows absence of triggered seismicity in the northern Peninsular Ranges and an increase of seismicity south of the Mexicali valley where the Imperial fault jumps southwest and the Cerro Prieto fault continues.

  20. Liquefaction and other ground failures in Imperial County, California, from the April 4, 2010, El Mayor-Cucapah earthquake

    USGS Publications Warehouse

    McCrink, Timothy P.; Pridmore, Cynthia L.; Tinsley, John C.; Sickler, Robert R.; Brandenberg, Scott J.; Stewart, Jonathan P.

    2011-01-01

    The Colorado River Delta region of southern Imperial Valley, California, and Mexicali Valley, Baja California, is a tectonically dynamic area characterized by numerous active faults and frequent large seismic events. Significant earthquakes that have been accompanied by surface fault rupture and/or soil liquefaction occurred in this region in 1892 (M7.1), 1915 (M6.3; M7.1), 1930 (M5.7), 1940 (M6.9), 1950 (M5.4), 1957 (M5.2), 1968 (6.5), 1979 (6.4), 1980 (M6.1), 1981 (M5.8), and 1987 (M6.2; M6.8). Following this trend, the M7.2 El Mayor-Cucapah earthquake of April 4, 2010, ruptured approximately 120 kilometers along several known faults in Baja California. Liquefaction caused by the M7.2 El Mayor-Cucapah earthquake was widespread throughout the southern Imperial Valley but concentrated in the southwest corner of the valley, southwest of the city centers of Calexico and El Centro where ground motions were highest. Although there are few strong motion recordings in the very western part of the area, the recordings that do exist indicate that ground motions were on the order of 0.3 to 0.6g where the majority of liquefaction occurrences were found. More distant liquefaction occurrences, at Fites Road southwest of Brawley and along Rosita Canal northwest of Holtville were triggered where ground motions were about 0.2 g. Damage to roads was associated mainly with liquefaction of sandy river deposits beneath bridge approach fills, and in some cases liquefaction within the fills. Liquefaction damage to canal and drain levees was not always accompanied by vented sand, but the nature of the damage leads the authors to infer that liquefaction was involved in the majority of observed cases. Liquefaction-related damage to several public facilities - Calexico Waste Water Treatment Plant, Fig Lagoon levee system, and Sunbeam Lake Dam in particular - appears to be extensive. The cost to repair these facilities to prevent future liquefaction damage will likely be prohibitive. As

  1. Hypocenter for the 1979 Imperial Valley Earthquake

    USGS Publications Warehouse

    Archuleta, Ralph J.

    1982-01-01

    Using P-and S-wave arrival times with the laterally varying P-wave velocity structure derived from analysis of a refraction survey of the Imperial Valley, a hypocenter is ascertained for the October 15, 1979, Imperial Valley earthquake: Latitude 32° 39.50′N, Longitude 115° 19.80′W, Depth 8.0 km, Time 23:16:54.40 GMT.

  2. GPS Imaging of Time-Variable Earthquake Hazard: The Hilton Creek Fault, Long Valley California

    NASA Astrophysics Data System (ADS)

    Hammond, W. C.; Blewitt, G.

    2016-12-01

    The Hilton Creek Fault, in Long Valley, California is a down-to-the-east normal fault that bounds the eastern edge of the Sierra Nevada/Great Valley microplate, and lies half inside and half outside the magmatically active caldera. Despite the dense coverage with GPS networks, the rapid and time-variable surface deformation attributable to sporadic magmatic inflation beneath the resurgent dome makes it difficult to use traditional geodetic methods to estimate the slip rate of the fault. While geologic studies identify cumulative offset, constrain timing of past earthquakes, and constrain a Quaternary slip rate to within 1-5 mm/yr, it is not currently possible to use geologic data to evaluate how the potential for slip correlates with transient caldera inflation. To estimate time-variable seismic hazard of the fault we estimate its instantaneous slip rate from GPS data using a new set of algorithms for robust estimation of velocity and strain rate fields and fault slip rates. From the GPS time series, we use the robust MIDAS algorithm to obtain time series of velocity that are highly insensitive to the effects of seasonality, outliers and steps in the data. We then use robust imaging of the velocity field to estimate a gridded time variable velocity field. Then we estimate fault slip rate at each time using a new technique that forms ad-hoc block representations that honor fault geometries, network complexity, connectivity, but does not require labor-intensive drawing of block boundaries. The results are compared to other slip rate estimates that have implications for hazard over different time scales. Time invariant long term seismic hazard is proportional to the long term slip rate accessible from geologic data. Contemporary time-invariant hazard, however, may differ from the long term rate, and is estimated from the geodetic velocity field that has been corrected for the effects of magmatic inflation in the caldera using a published model of a dipping ellipsoidal

  3. Earthquakes and faults in southern California (1970-2010)

    USGS Publications Warehouse

    Sleeter, Benjamin M.; Calzia, James P.; Walter, Stephen R.

    2012-01-01

    The map depicts both active and inactive faults and earthquakes magnitude 1.5 to 7.3 in southern California (1970–2010). The bathymetry was generated from digital files from the California Department of Fish And Game, Marine Region, Coastal Bathymetry Project. Elevation data are from the U.S. Geological Survey National Elevation Database. Landsat satellite image is from fourteen Landsat 5 Thematic Mapper scenes collected between 2009 and 2010. Fault data are reproduced with permission from 2006 California Geological Survey and U.S. Geological Survey data. The earthquake data are from the U.S. Geological Survey National Earthquake Information Center.

  4. Structure of the San Fernando Valley region, California: implications for seismic hazard and tectonic history

    USGS Publications Warehouse

    Langenheim, V.E.; Wright, T.L.; Okaya, D.A.; Yeats, R.S.; Fuis, G.S.; Thygesen, K.; Thybo, H.

    2011-01-01

    Industry seismic reflection data, oil test well data, interpretation of gravity and magnetic data, and seismic refraction deep-crustal profiles provide new perspectives on the subsurface geology of San Fernando Valley, home of two of the most recent damaging earthquakes in southern California. Seismic reflection data provide depths to Miocene–Quaternary horizons; beneath the base of the Late Miocene Modelo Formation are largely nonreflective rocks of the Middle Miocene Topanga and older formations. Gravity and seismic reflection data reveal the North Leadwell fault zone, a set of down-to-the-north faults that does not offset the top of the Modelo Formation; the zone strikes northwest across the valley, and may be part of the Oak Ridge fault system to the west. In the southeast part of the valley, the fault zone bounds a concealed basement high that influenced deposition of the Late Miocene Tarzana fan and may have localized damage from the 1994 Northridge earthquake. Gravity and seismic refraction data indicate that the basin underlying San Fernando Valley is asymmetric, the north part of the basin (Sylmar subbasin) reaching depths of 5–8 km. Magnetic data suggest a major boundary at or near the Verdugo fault, which likely started as a Miocene transtensional fault, and show a change in the dip sense of the fault along strike. The northwest projection of the Verdugo fault separates the Sylmar subbasin from the main San Fernando Valley and coincides with the abrupt change in structural style from the Santa Susana fault to the Sierra Madre fault. The Simi Hills bound the basin on the west and, as defined by gravity data, the boundary is linear and strikes ~N45°E. That northeast-trending gravity gradient follows both the part of the 1971 San Fernando aftershock distribution called the Chatsworth trend and the aftershock trends of the 1994 Northridge earthquake. These data suggest that the 1971 San Fernando and 1994 Northridge earthquakes reactivated portions of

  5. Evidence of shallow fault zone strengthening after the 1992 M7.5 Landers, California, earthquake

    USGS Publications Warehouse

    Li, Y.-G.; Vidale, J.E.; Aki, K.; Xu, Fei; Burdette, T.

    1998-01-01

    Repeated seismic surveys of the Landers, California, fault zone that ruptured in the magnitude (M) 7.5 earthquake of 1992 reveal an increase in seismic velocity with time. P, S, and fault zone trapped waves were excited by near-surface explosions in two locations in 1994 and 1996, and were recorded on two linear, three-component seismic arrays deployed across the Johnson Valley fault trace. The travel times of P and S waves for identical shot-receiver pairs decreased by 0.5 to 1.5 percent from 1994 to 1996, with the larger changes at stations located within the fault zone. These observations indicate that the shallow Johnson Valley fault is strengthening after the main shock, most likely because of closure of cracks that were opened by the 1992 earthquake. The increase in velocity is consistent with the prevalence of dry over wet cracks and with a reduction in the apparent crack density near the fault zone by approximately 1.0 percent from 1994 to 1996.

  6. Children and the San Fernando earthquake

    USGS Publications Warehouse

    Howard, S. J.

    1980-01-01

    Before dawn, on February 9, 1971, a magnitude 6.4 earthquake occurred in the San Fernando Valley of California. On the following day, theSan Fernando Valley Child Guidance Clinic, through radio and newspapers, offered mental health crises services to children frightened by the earthquake. Response to this invitation was immediate and almost overwhelming. During the first 2 weeks, the Clinic's staff counseled hundreds of children who were experiencing various degrees of anxiety. 

  7. Seismic site characterization of an urban dedimentary basin, Livermore Valley, California: Site tesponse, basin-edge-induced surface waves, and 3D simulations

    USGS Publications Warehouse

    Hartzell, Stephen; Leeds, Alena L.; Ramirez-Guzman, Leonardo; Allen, James P.; Schmitt, Robert G.

    2016-01-01

    Thirty‐two accelerometers were deployed in the Livermore Valley, California, for approximately one year to study sedimentary basin effects. Many local and near‐regional earthquakes were recorded, including the 24 August 2014 Mw 6.0 Napa, California, earthquake. The resulting ground‐motion data set is used to quantify the seismic response of the Livermore basin, a major structural depression in the California Coast Range Province bounded by active faults. Site response is calculated by two methods: the reference‐site spectral ratio method and a source‐site spectral inversion method. Longer‐period (≥1  s) amplification factors follow the same general pattern as Bouguer gravity anomaly contours. Site response spectra are inverted for shallow shear‐wave velocity profiles, which are consistent with independent information. Frequency–wavenumber analysis is used to analyze plane‐wave propagation across the Livermore Valley and to identify basin‐edge‐induced surface waves with back azimuths different from the source back azimuth. Finite‐element simulations in a 3D velocity model of the region illustrate the generation of basin‐edge‐induced surface waves and point out strips of elevated ground velocities along the margins of the basin.

  8. The October 1992 Parkfield, California, earthquake prediction

    USGS Publications Warehouse

    Langbein, J.

    1992-01-01

    A magnitude 4.7 earthquake occurred near Parkfield, California, on October 20, 992, at 05:28 UTC (October 19 at 10:28 p.m. local or Pacific Daylight Time).This moderate shock, interpreted as the potential foreshock of a damaging earthquake on the San Andreas fault, triggered long-standing federal, state and local government plans to issue a public warning of an imminent magnitude 6 earthquake near Parkfield. Although the predicted earthquake did not take place, sophisticated suites of instruments deployed as part of the Parkfield Earthquake Prediction Experiment recorded valuable data associated with an unusual series of events. this article describes the geological aspects of these events, which occurred near Parkfield in October 1992. The accompnaying article, an edited version of a press conference b Richard Andrews, the Director of the California Office of Emergency Service (OES), describes governmental response to the prediction.   

  9. Uniform California earthquake rupture forecast, version 2 (UCERF 2)

    USGS Publications Warehouse

    Field, E.H.; Dawson, T.E.; Felzer, K.R.; Frankel, A.D.; Gupta, V.; Jordan, T.H.; Parsons, T.; Petersen, M.D.; Stein, R.S.; Weldon, R.J.; Wills, C.J.

    2009-01-01

    The 2007 Working Group on California Earthquake Probabilities (WGCEP, 2007) presents the Uniform California Earthquake Rupture Forecast, Version 2 (UCERF 2). This model comprises a time-independent (Poisson-process) earthquake rate model, developed jointly with the National Seismic Hazard Mapping Program and a time-dependent earthquake-probability model, based on recent earthquake rates and stress-renewal statistics conditioned on the date of last event. The models were developed from updated statewide earthquake catalogs and fault deformation databases using a uniform methodology across all regions and implemented in the modular, extensible Open Seismic Hazard Analysis framework. The rate model satisfies integrating measures of deformation across the plate-boundary zone and is consistent with historical seismicity data. An overprediction of earthquake rates found at intermediate magnitudes (6.5 ??? M ???7.0) in previous models has been reduced to within the 95% confidence bounds of the historical earthquake catalog. A logic tree with 480 branches represents the epistemic uncertainties of the full time-dependent model. The mean UCERF 2 time-dependent probability of one or more M ???6.7 earthquakes in the California region during the next 30 yr is 99.7%; this probability decreases to 46% for M ???7.5 and to 4.5% for M ???8.0. These probabilities do not include the Cascadia subduction zone, largely north of California, for which the estimated 30 yr, M ???8.0 time-dependent probability is 10%. The M ???6.7 probabilities on major strike-slip faults are consistent with the WGCEP (2003) study in the San Francisco Bay Area and the WGCEP (1995) study in southern California, except for significantly lower estimates along the San Jacinto and Elsinore faults, owing to provisions for larger multisegment ruptures. Important model limitations are discussed.

  10. The southern California uplift and associated earthquakes

    USGS Publications Warehouse

    Castle, R.O.; Bernknopf, R.L.

    1996-01-01

    Southern California earthquakes ??? M5.5 during the period 1955/01/01-1994/01/17 were concentrated along or adjacent to the south flank of the southern California uplift, as defined both at its culmination and following its partial collapse. Spatial clustering of these earthquakes within three more-or-less distinct groups suggests either gaps along the south flank that were previously filled or are yet to be filled. Nearly all of the indicated earthquakes accompanied or followed partial collapse of the uplift, and seismic activity within this regime seems to have been increasing through at least 1994/01/17. Copyright 1996 by the American Geophysical Union.

  11. THE GREAT SOUTHERN CALIFORNIA SHAKEOUT: Earthquake Science for 22 Million People

    NASA Astrophysics Data System (ADS)

    Jones, L.; Cox, D.; Perry, S.; Hudnut, K.; Benthien, M.; Bwarie, J.; Vinci, M.; Buchanan, M.; Long, K.; Sinha, S.; Collins, L.

    2008-12-01

    Earthquake science is being communicated to and used by the 22 million residents of southern California to improve resiliency to future earthquakes through the Great Southern California ShakeOut. The ShakeOut began when the USGS partnered with the California Geological Survey, Southern California Earthquake Center and many other organizations to bring 300 scientists and engineers together to formulate a comprehensive description of a plausible major earthquake, released in May 2008, as the ShakeOut Scenario, a description of the impacts and consequences of a M7.8 earthquake on the Southern San Andreas Fault (USGS OFR2008-1150). The Great Southern California ShakeOut was a week of special events featuring the largest earthquake drill in United States history. The ShakeOut drill occurred in houses, businesses, and public spaces throughout southern California at 10AM on November 13, 2008, when southern Californians were asked to pretend that the M7.8 scenario earthquake had occurred and to practice actions that could reduce the impact on their lives. Residents, organizations, schools and businesses registered to participate in the drill through www.shakeout.org where they could get accessible information about the scenario earthquake and share ideas for better reparation. As of September 8, 2008, over 2.7 million confirmed participants had been registered. The primary message of the ShakeOut is that what we do now, before a big earthquake, will determine what our lives will be like after. The goal of the ShakeOut has been to change the culture of earthquake preparedness in southern California, making earthquakes a reality that are regularly discussed. This implements the sociological finding that 'milling,' discussing a problem with loved ones, is a prerequisite to taking action. ShakeOut milling is taking place at all levels from individuals and families, to corporations and governments. Actions taken as a result of the ShakeOut include the adoption of earthquake

  12. Triggered deformation and seismic activity under Mammoth Mountain in long Valley caldera by the 3 November 2002 Mw 7.9 Denali fault earthquake

    USGS Publications Warehouse

    Johnston, M.J.S.; Prejean, S.G.; Hill, D.P.

    2004-01-01

    The 3 November 2002 Mw 7.9 Denali fault earthquake triggered deformational offsets and microseismicity under Mammoth Mountain (MM) on the rim of Long Valley caldera, California, some 3460 km from the earthquake. Such strain offsets and microseismicity were not recorded at other borehole strain sites along the San Andreas fault system in California. The Long Valley offsets were recorded on borehole strainmeters at three sites around the western part of the caldera that includes Mammoth Mountain - a young volcano on the southwestern rim of the caldera. The largest recorded strain offsets were -0.1 microstrain at PO on the west side of MM, 0.05 microstrain at MX to the southeast of MM, and -0.025 microstrain at BS to the northeast of MM with negative strain extensional. High sample rate strain data show initial triggering of the offsets began at 22:30 UTC during the arrival of the first Rayleigh waves from the Alaskan earthquake with peak-to-peak dynamic strain amplitudes of about 2 microstrain corresponding to a stress amplitude of about 0.06 MPa. The strain offsets grew to their final values in the next 10 min. The associated triggered seismicity occurred beneath the south flank of MM and also began at 22:30 UTC and died away over the next 15 min. This relatively weak seismicity burst included some 60 small events with magnitude all less than M = 1. While poorly constrained, these strain observations are consistent with triggered slip and intrusive opening on a north-striking normal fault centered at a depth of 8 km with a moment of l016 N m, or the equivalent of a M 4.3 earthquake. The cumulative seismic moment for the associated seismicity burst was more than three orders of magnitude smaller. These observations and this model resemble those for the triggered deformation and slip that occurred beneath the north side of MM following the 16 October 1999 M 7.1 Hector Mine, California, earthquake. However, in this case, we see little post-event slip decay reflected in

  13. Discrepancy between earthquake rates implied by historic earthquakes and a consensus geologic source model for California

    USGS Publications Warehouse

    Petersen, M.D.; Cramer, C.H.; Reichle, M.S.; Frankel, A.D.; Hanks, T.C.

    2000-01-01

    We examine the difference between expected earthquake rates inferred from the historical earthquake catalog and the geologic data that was used to develop the consensus seismic source characterization for the state of California [California Department of Conservation, Division of Mines and Geology (CDMG) and U.S. Geological Survey (USGS) Petersen et al., 1996; Frankel et al., 1996]. On average the historic earthquake catalog and the seismic source model both indicate about one M 6 or greater earthquake per year in the state of California. However, the overall earthquake rates of earthquakes with magnitudes (M) between 6 and 7 in this seismic source model are higher, by at least a factor of 2, than the mean historic earthquake rates for both southern and northern California. The earthquake rate discrepancy results from a seismic source model that includes earthquakes with characteristic (maximum) magnitudes that are primarily between M 6.4 and 7.1. Many of these faults are interpreted to accommodate high strain rates from geologic and geodetic data but have not ruptured in large earthquakes during historic time. Our sensitivity study indicates that the rate differences between magnitudes 6 and 7 can be reduced by adjusting the magnitude-frequency distribution of the source model to reflect more characteristic behavior, by decreasing the moment rate available for seismogenic slip along faults, by increasing the maximum magnitude of the earthquake on a fault, or by decreasing the maximum magnitude of the background seismicity. However, no single parameter can be adjusted, consistent with scientific consensus, to eliminate the earthquake rate discrepancy. Applying a combination of these parametric adjustments yields an alternative earthquake source model that is more compatible with the historic data. The 475-year return period hazard for peak ground and 1-sec spectral acceleration resulting from this alternative source model differs from the hazard resulting from the

  14. California's Central Valley Groundwater Study: A Powerful New Tool to Assess Water Resources in California's Central Valley

    USGS Publications Warehouse

    Faunt, Claudia C.; Hanson, Randall T.; Belitz, Kenneth; Rogers, Laurel

    2009-01-01

    Competition for water resources is growing throughout California, particularly in the Central Valley. Since 1980, the Central Valley's population has nearly doubled to 3.8 million people. It is expected to increase to 6 million by 2020. Statewide population growth, anticipated reductions in Colorado River water deliveries, drought, and the ecological crisis in the Sacramento-San Joaquin Delta have created an intense demand for water. Tools and information can be used to help manage the Central Valley aquifer system, an important State and national resource.

  15. Earthquake alarm; operating the seismograph station at the University of California, Berkeley.

    USGS Publications Warehouse

    Stump, B.

    1980-01-01

    At the University of California seismographic stations, the task of locating and determining magnitudes for both local and distant earthquakes is a continuous one. Teleseisms must be located rapidly so that events that occur in the Pacific can be identified and the Pacific Tsunami Warning System alerted. For great earthquakes anywhere, there is a responsibility to notify public agencies such as the California Office of Emergency Services, the Federal Disaster Assistance Administration, the Earthquake Engineering Research Institute, the California Seismic Safety Commission, and the American Red Cross. In the case of damaging local earthquakes, it is necessary to alert also the California Department of Water Resources, California Division of Mines and Geology, U.S Army Corps of Engineers, Federal Bureau of Reclamation, and the Bay Area Rapid Transit. These days, any earthquakes that are felt in northern California cause immediate inquiries from the news media and an interested public. The series of earthquakes that jolted the Livermore area from January 24 to 26 1980, is a good case in point. 

  16. Groundwater quality in Coachella Valley, California

    USGS Publications Warehouse

    Dawson, Barbara J. Milby; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Coachella Valley is one of the study areas being evaluated. The Coachella study area is approximately 820 square miles (2,124 square kilometers) and includes the Coachella Valley groundwater basin (California Department of Water Resources, 2003). Coachella Valley has an arid climate, with average annual rainfall of about 6 inches (15 centimeters). The runoff from the surrounding mountains drains to rivers that flow east and south out of the study area to the Salton Sea. Land use in the study area is approximately 67 percent (%) natural, 21% agricultural, and 12% urban. The primary natural land cover is shrubland. The largest urban areas are the cities of Indio and Palm Springs (2010 populations of 76,000 and 44,000, respectively). Groundwater in this basin is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from surrounding mountains. The primary aquifers in Coachella Valley are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells in Coachella Valley are completed to depths between 490 and 900 feet (149 to 274 meters), consist of solid casing from the land surface to a depth of 260 to 510 feet (79 to 155 meters), and are screened or perforated below the solid casing. Recharge to the groundwater system is primarily runoff from the surrounding mountains, and by direct infiltration of irrigation. The primary sources of discharge are pumping wells, evapotranspiration, and underflow to

  17. Results of the Regional Earthquake Likelihood Models (RELM) test of earthquake forecasts in California.

    PubMed

    Lee, Ya-Ting; Turcotte, Donald L; Holliday, James R; Sachs, Michael K; Rundle, John B; Chen, Chien-Chih; Tiampo, Kristy F

    2011-10-04

    The Regional Earthquake Likelihood Models (RELM) test of earthquake forecasts in California was the first competitive evaluation of forecasts of future earthquake occurrence. Participants submitted expected probabilities of occurrence of M ≥ 4.95 earthquakes in 0.1° × 0.1° cells for the period 1 January 1, 2006, to December 31, 2010. Probabilities were submitted for 7,682 cells in California and adjacent regions. During this period, 31 M ≥ 4.95 earthquakes occurred in the test region. These earthquakes occurred in 22 test cells. This seismic activity was dominated by earthquakes associated with the M = 7.2, April 4, 2010, El Mayor-Cucapah earthquake in northern Mexico. This earthquake occurred in the test region, and 16 of the other 30 earthquakes in the test region could be associated with it. Nine complete forecasts were submitted by six participants. In this paper, we present the forecasts in a way that allows the reader to evaluate which forecast is the most "successful" in terms of the locations of future earthquakes. We conclude that the RELM test was a success and suggest ways in which the results can be used to improve future forecasts.

  18. Results of the Regional Earthquake Likelihood Models (RELM) test of earthquake forecasts in California

    PubMed Central

    Lee, Ya-Ting; Turcotte, Donald L.; Holliday, James R.; Sachs, Michael K.; Rundle, John B.; Chen, Chien-Chih; Tiampo, Kristy F.

    2011-01-01

    The Regional Earthquake Likelihood Models (RELM) test of earthquake forecasts in California was the first competitive evaluation of forecasts of future earthquake occurrence. Participants submitted expected probabilities of occurrence of M≥4.95 earthquakes in 0.1° × 0.1° cells for the period 1 January 1, 2006, to December 31, 2010. Probabilities were submitted for 7,682 cells in California and adjacent regions. During this period, 31 M≥4.95 earthquakes occurred in the test region. These earthquakes occurred in 22 test cells. This seismic activity was dominated by earthquakes associated with the M = 7.2, April 4, 2010, El Mayor–Cucapah earthquake in northern Mexico. This earthquake occurred in the test region, and 16 of the other 30 earthquakes in the test region could be associated with it. Nine complete forecasts were submitted by six participants. In this paper, we present the forecasts in a way that allows the reader to evaluate which forecast is the most “successful” in terms of the locations of future earthquakes. We conclude that the RELM test was a success and suggest ways in which the results can be used to improve future forecasts. PMID:21949355

  19. 27 CFR 9.37 - California Shenandoah Valley.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false California Shenandoah Valley. 9.37 Section 9.37 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU...) Boundaries. The Shenandoah Valley viticultural Area is located in portions of Amador and El Dorado Counties...

  20. 27 CFR 9.37 - California Shenandoah Valley.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false California Shenandoah Valley. 9.37 Section 9.37 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU...) Boundaries. The Shenandoah Valley viticultural Area is located in portions of Amador and El Dorado Counties...

  1. The Mississippi Valley earthquakes of 1811 and 1812

    USGS Publications Warehouse

    Nuttli, O.W.

    1974-01-01

    Shortly after 2 o'clock on the morning of December 16, 1811, the Mississippi River valley was convulsed by an earthquake so severe that it awakened people in cities as distant as Pittsburgh, Pennsylvania, and Norfolk, Virginia. This shock inaugurated what must have been the most frightening sequence of earthquakes ever to occur in the United States. Intermittent strong shaking continued through March 1812 and aftershocks strong enough to be felt occurred through the year 1817. The initial earthquake of December 16 was followed by other principal shocks, one on January 23, 1812, and the other on February 7, 182. Judging from newspaper accounts of damage to buildings, the February 7 earthquake was the biggest of the three. 

  2. Landslides triggered by the 1994 Northridge, California, earthquake

    USGS Publications Warehouse

    Harp, E.L.; Jibson, R.W.

    1996-01-01

    The 17 January 1994 Northridge, California, earthquake (Mw, = 6.7) triggered more than 11,000 landslides over an area of about 10,000 km2. Most of the landslides were concentrated in a 1000-km2 area that included the Santa Susana Mountains and the mountains north of the Santa Clara River valley. We mapped landslides triggered by the earthquake in the field and from 1:60,000-nominal-scale aerial photography provided by the U.S. Air Force and taken the morning of the earthquake; these mapped landslides were subsequently digitized and plotted in a GIS-based format. Most of the triggered landslides were shallow (1- to 5-m thick), highly disrupted falls and slides within weakly cemented Tertiary to Pleistocene clastic sediment. Average volumes of these types of landslides were less than 1000 m3, but many had volumes exceeding 100,000 m3. The larger disrupted slides commonly had runout paths of more than 50 m, and a few traveled as far as 200 m from the bases of steep parent slopes. Deeper (>5-m thick) rotational slumps and block slides numbered in the tens to perhaps hundreds, a few of which exceeded 100,000 m3 in volume. Most of these were reactivations of previously existing landslides. The largest single landslide triggered by the earthquake was a rotational slump/block slide having a volume of 8 ?? 106 m3. Analysis of the mapped landslide distribution with respect to variations in (1) landslide susceptibility and (2) strong shaking recorded by hundreds of instruments will form the basis of a seismic landslide hazard analysis of the Los Angeles area.

  3. Death Valley California as seen from STS-59

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This oblique handheld Hasselblad 70mm photo shows Death Valley, near California's border with Nevada. The valley -- the central feature of Death Valley National Monument -- extends north to south for some 140 miles (225 kilometers). Hemmed in to the east by the Amargosa Range and to the west by the Panamints, its width varies from 5 to 15 miles (8 to 24 kilometers).

  4. UCERF3: A new earthquake forecast for California's complex fault system

    USGS Publications Warehouse

    Field, Edward H.; ,

    2015-01-01

    With innovations, fresh data, and lessons learned from recent earthquakes, scientists have developed a new earthquake forecast model for California, a region under constant threat from potentially damaging events. The new model, referred to as the third Uniform California Earthquake Rupture Forecast, or "UCERF" (http://www.WGCEP.org/UCERF3), provides authoritative estimates of the magnitude, location, and likelihood of earthquake fault rupture throughout the state. Overall the results confirm previous findings, but with some significant changes because of model improvements. For example, compared to the previous forecast (Uniform California Earthquake Rupture Forecast 2), the likelihood of moderate-sized earthquakes (magnitude 6.5 to 7.5) is lower, whereas that of larger events is higher. This is because of the inclusion of multifault ruptures, where earthquakes are no longer confined to separate, individual faults, but can occasionally rupture multiple faults simultaneously. The public-safety implications of this and other model improvements depend on several factors, including site location and type of structure (for example, family dwelling compared to a long-span bridge). Building codes, earthquake insurance products, emergency plans, and other risk-mitigation efforts will be updated accordingly. This model also serves as a reminder that damaging earthquakes are inevitable for California. Fortunately, there are many simple steps residents can take to protect lives and property.

  5. Unrest in Long Valley Caldera, California, 1978-2004

    USGS Publications Warehouse

    Hill, David P.; ,

    2006-01-01

    Long Valley Caldera and the Mono-Inyo Domes volcanic field in eastern California lie in a left-stepping offset along the eastern escarpment of the Sierra Nevada, at the northern end of the Owens Valley and the western margin of the Basin and Range Province. Over the last 4 Ma, this volcanic field has produced multiple volcanic eruptions, including the caldera-forming eruption at 760 000 a BP and the recent Mono-Inyo Domes eruptions 500–660 a BP and 250 a BP. Beginning in the late 1970s, the caldera entered a sustained period of unrest that persisted through the end of the century without culminating in an eruption. The unrest has included recurring earthquake swarms; tumescence of the resurgent dome by nearly 80 cm; the onset of diffuse magmatic carbon dioxide emissions around the flanks of Mammoth Mountain on the southwest margin of the caldera; and other indicators of magma transport at mid- to upper-crustal depths. Although we have made substantial progress in understanding the processes driving this unrest, many key questions remain, including the distribution, size, and relation between magma bodies within the mid-to-upper crust beneath the caldera, Mammoth Mountain, and the Inyo Mono volcanic chain, and how these magma bodies are connected to the roots of the magmatic system in the lower crust or upper mantle.

  6. SRTM Perspective View with Landsat Overlay: San Fernando Valley, California

    NASA Image and Video Library

    2000-10-12

    The San Fernando Valley lower right of center is part of Los Angeles and includes well over one million people. Two major disasters have occurred here in the last few decades: the 1971 Sylmar earthquake and the 1994 Northridge earthquake.

  7. Earthquakes in Tuhinj Valley (Slovenia) In 1840

    NASA Astrophysics Data System (ADS)

    Cecić, Ina

    2015-04-01

    A less known damaging earthquake in southern part of Kamnik-Savinja Alps, Slovenia, in 1840 is described. The main shock was on 27 August 1840 with the epicentre in Tuhinj Valley. The maximum intensity was VII EMS-98 in Ljubljana, Slovenia, and in Eisenkappel, Austria. It was felt as far as Venice, Italy, 200 km away. The macroseismic magnitude of the main shock, estimated from the area of intensity VI EMS-98, was 5.0. The effects of the main shock and its aftershocks are described, and an earthquake catalogue for Slovenia in 1840 is provided. Available primary sources (newspaper articles) are presented.

  8. Recent landscape change in California's Central Valley

    NASA Astrophysics Data System (ADS)

    Soulard, C. E.; Wilson, T. S.

    2012-12-01

    Long term monitoring of land use and land cover in California's intensively farmed Central Valley reveals several key physical and socioeconomic factors driving landscape change. As part of the USGS Land Cover Trends Project, we analyzed modern land-use/land-cover change for the California Central Valley ecoregion between 2000 and 2010, monitoring annual change between 2005 and 2010, while creating two new change intervals (2000-2005 and 2005-2010) to update the existing 27-year, interval-based analysis. Between 2000 and 2010, agricultural lands fluctuated due to changes in water allocations and emerging drought conditions, or were lost permanently to development (240 square km). Land-use pressure from agriculture and development also led to a decline in grasslands and shrublands across the region (280 square km). Overall, 400 square km of new developed lands were added in the first decade of the 21st century. From 2007 to 2010, development only expanded by 50 square km, coinciding with defaults in the banking system, the onset of historic foreclosure crisis in California and the global economic downturn. Our annual LULC change estimates capture landscape-level change in response to regional policy changes, climate, and fluctuations (e.g., growth or decline) in the national and global economy. The resulting change data provide insights into the drivers of landscape change in the California Central Valley and the combination of two consistent mapping efforts represents the first continuous, 37-year endeavor of its kind.

  9. Modeling and validation of a 3D velocity structure for the Santa Clara Valley, California, for seismic-wave simulations

    USGS Publications Warehouse

    Hartzell, S.; Harmsen, S.; Williams, R.A.; Carver, D.; Frankel, A.; Choy, G.; Liu, P.-C.; Jachens, R.C.; Brocher, T.M.; Wentworth, C.M.

    2006-01-01

    A 3D seismic velocity and attenuation model is developed for Santa Clara Valley, California, and its surrounding uplands to predict ground motions from scenario earthquakes. The model is developed using a variety of geologic and geophysical data. Our starting point is a 3D geologic model developed primarily from geologic mapping and gravity and magnetic surveys. An initial velocity model is constructed by using seismic velocities from boreholes, reflection/refraction lines, and spatial autocorrelation microtremor surveys. This model is further refined and the seismic attenuation is estimated through waveform modeling of weak motions from small local events and strong-ground motion from the 1989 Loma Prieta earthquake. Waveforms are calculated to an upper frequency of 1 Hz using a parallelized finite-difference code that utilizes two regions with a factor of 3 difference in grid spacing to reduce memory requirements. Cenozoic basins trap and strongly amplify ground motions. This effect is particularly strong in the Evergreen Basin on the northeastern side of the Santa Clara Valley, where the steeply dipping Silver Creek fault forms the southwestern boundary of the basin. In comparison, the Cupertino Basin on the southwestern side of the valley has a more moderate response, which is attributed to a greater age and velocity of the Cenozoic fill. Surface waves play a major role in the ground motion of sedimentary basins, and they are seen to strongly develop along the western margins of the Santa Clara Valley for our simulation of the Loma Prieta earthquake.

  10. Groundwater availability of the Central Valley Aquifer, California

    USGS Publications Warehouse

    Faunt, Claudia C.

    2009-01-01

    California's Central Valley covers about 20,000 square miles and is one of the most productive agricultural regions in the world. More than 250 different crops are grown in the Central Valley with an estimated value of $17 billion per year. This irrigated agriculture relies heavily on surface-water diversions and groundwater pumpage. Approximately one-sixth of the Nation's irrigated land is in the Central Valley, and about one-fifth of the Nation's groundwater demand is supplied from its aquifers. The Central Valley also is rapidly becoming an important area for California's expanding urban population. Since 1980, the population of the Central Valley has nearly doubled from 2 million to 3.8 million people. The Census Bureau projects that the Central Valley's population will increase to 6 million people by 2020. This surge in population has increased the competition for water resources within the Central Valley and statewide, which likely will be exacerbated by anticipated reductions in deliveries of Colorado River water to southern California. In response to this competition for water, a number of water-related issues have gained prominence: conservation of agricultural land, conjunctive use, artificial recharge, hydrologic implications of land-use change, and effects of climate variability. To provide information to stakeholders addressing these issues, the USGS Groundwater Resources Program made a detailed assessment of groundwater availability of the Central Valley aquifer system, that includes: (1) the present status of groundwater resources; (2) how these resources have changed over time; and (3) tools to assess system responses to stresses from future human uses and climate variability and change. This effort builds on previous investigations, such as the USGS Central Valley Regional Aquifer System and Analysis (CV-RASA) project and several other groundwater studies in the Valley completed by Federal, State and local agencies at differing scales. The

  11. View of the Salinas River Valley area south of Monterey Bay, California

    NASA Image and Video Library

    1973-08-15

    SL3-88-004 (July-September 1973) --- A vertical view of the Salinas River Valley area south of Monterey Bay, California area is seen in this Skylab 3 Earth Resources Experiments Package S190-B (five-inch Earth terrain camera) photograph taken from the Skylab space station in Earth orbit. The valley is an irrigated agricultural area, and is indicated by the dark-green and light-gray rectangular patterns in the centre of the picture. The city of Salinas is barely visible under the cloud cover at the top (north) end of the valley. The dark mass on the left (west) side of the valley is the Santa Lucia mountain range. The Big Sur area is on the left and partly covered by clouds. The Diablo Range forms the dark mass in the lower right (southeast) corner of the photograph. The town of Hollister is the gray area in the dark-green rectangular farm tracts which occupy the floor of the San Benito Valley in the upper right (northeast) corner of the photograph. The Salinas River flows northwestward toward Monterey Bay. The towns of Soledad, Greenfield and King City appear as gray areas along U.S. 101 in the Salinas Valley. The geology of the area is complex, and has been racked by several earthquakes resulting from movement along the San Andreas and subsidiary faults. Here, the surface expression of the San Andreas Fault can be traced from a point just west of Hollister at the contrast of dark brown and tan to a point about one inch left of the lower right (southeast) corner of the picture. Subsidiary faults are indicated by the curving trend of the rocks along the right side. The photograph will provide detailed information on land use patterns (Dr. R. Colwell, University of California, Berkeley) and fault tectonics (Dr. P. Merifield, Earth Science Res., Inc. and Dr. M. Abdel-Gawad, Rockwell International). Federal agencies participating with NASA on the EREP project are the Departments of Agriculture, Commerce, Interior, the Environmental Protection Agency and the Corps of

  12. Groundwater quality in the Antelope Valley, California

    USGS Publications Warehouse

    Dawson, Barbara J. Milby; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Antelope Valley is one of the study areas being evaluated. The Antelope study area is approximately 1,600 square miles (4,144 square kilometers) and includes the Antelope Valley groundwater basin (California Department of Water Resources, 2003). Antelope Valley has an arid climate and is part of the Mojave Desert. Average annual rainfall is about 6 inches (15 centimeters). The study area has internal drainage, with runoff from the surrounding mountains draining towards dry lakebeds in the lower parts of the valley. Land use in the study area is approximately 68 percent (%) natural (mostly shrubland and grassland), 24% agricultural, and 8% urban. The primary crops are pasture and hay. The largest urban areas are the cities of Palmdale and Lancaster (2010 populations of 152,000 and 156,000, respectively). Groundwater in this basin is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from surrounding mountains. The primary aquifers in Antelope Valley are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells in Antelope Valley are completed to depths between 360 and 700 feet (110 to 213 meters), consist of solid casing from the land surface to a depth of 180 to 350 feet (55 to 107 meters), and are screened or perforated below the solid casing. Recharge to the groundwater system is primarily runoff from the surrounding mountains, and by direct infiltration of irrigation and sewer and septic

  13. California Earthquake Residual Transportation Capability Study

    DOT National Transportation Integrated Search

    1983-12-01

    This report addresses the ability of transportation facilities in California to survive four postulated earthquakes that are based on historical events. The survival of highways, railroads, ports, airports, and pipelines is investigated following ind...

  14. Death Valley, California

    NASA Image and Video Library

    1994-04-11

    STS059-S-026 (11 April 1994) --- This is an image of Death Valley, California, centered at 36.629 degrees north latitude, 117.069 degrees west longitude. The image shows Furnace Creek alluvial fan and Furnace Creek Ranch at the far right, and the sand dunes near Stove Pipe Wells at the center. The dark fork-shaped feature between Furnace Creek fan and the dunes is a smooth flood-plain which encloses Cottonball Basin. The SIR-C/X-SAR supersite is an area of extensive field investigations and has been visited by both Space Radar Lab astronaut crews. Elevations in the Valley range from 70 meters below sea level, the lowest in the United States, to more than 3300 meters above sea level. Scientists are using SIR-C/X-SAR data from Death Valley to help answer a number of different questions about the Earth's geology. One question concerns how alluvial fans are formed and change through time under the influence of climatic changes and earthquakes. Alluvial fans are gravel deposits that wash down from the mountains over time. They are visible in the image as circular, fan-shaped bright areas extending into the darker valley floor from the mountains. Information about the alluvial fans help scientists study Earth's ancient climate. Scientists know the fans are bulit up through climatic and tectonic processes and they will use the SIR-C/X-SAR data to understand the nature and rates of weathering processes on the fans, soil formation, and the transport of sand and dust by the wind. SIR-C/X-SAR's sensitivity to centimeter-scale (or inch-scale) roughness provides detailed maps of surface texture. Such information can be used to study the occurrence and movement of dust storms and sand dunes. the goal of these studies is to gain a better understanding of the record of past climatic changes and the effects of those changes on a sensitive environment. This may lead to a better ability to predict future response of the land to different potential global cimate-change scenarios

  15. Repeated catastrophic valley infill following medieval earthquakes in the Nepal Himalaya.

    PubMed

    Schwanghart, Wolfgang; Bernhardt, Anne; Stolle, Amelie; Hoelzmann, Philipp; Adhikari, Basanta R; Andermann, Christoff; Tofelde, Stefanie; Merchel, Silke; Rugel, Georg; Fort, Monique; Korup, Oliver

    2016-01-08

    Geomorphic footprints of past large Himalayan earthquakes are elusive, although they are urgently needed for gauging and predicting recovery times of seismically perturbed mountain landscapes. We present evidence of catastrophic valley infill following at least three medieval earthquakes in the Nepal Himalaya. Radiocarbon dates from peat beds, plant macrofossils, and humic silts in fine-grained tributary sediments near Pokhara, Nepal's second-largest city, match the timing of nearby M > 8 earthquakes in ~1100, 1255, and 1344 C.E. The upstream dip of tributary valley fills and x-ray fluorescence spectrometry of their provenance rule out local sources. Instead, geomorphic and sedimentary evidence is consistent with catastrophic fluvial aggradation and debris flows that had plugged several tributaries with tens of meters of calcareous sediment from a Higher Himalayan source >60 kilometers away. Copyright © 2016, American Association for the Advancement of Science.

  16. Two examples of earthquake- hazard reduction in southern California.

    USGS Publications Warehouse

    Kockelman, W.J.; Campbell, C.C.

    1983-01-01

    Because California is seismically active, planners and decisionmakers must try to anticipate earthquake hazards there and, where possible, to reduce the hazards. Geologic and seismologic information provides the basis for the necessary plans and actions. Two examples of how such information is used are presented. The first involves assessing the impact of a major earthquake on critical facilities in southern California, and the second involves strengthening or removing unsafe masonry buildings in the Los Angeles area. -from Authors

  17. Predicted liquefaction in the greater Oakland area and northern Santa Clara Valley during a repeat of the 1868 Hayward Fault (M6.7-7.0) earthquake

    USGS Publications Warehouse

    Holzer, Thomas L.; Noce, Thomas E.; Bennett, Michael J.

    2010-01-01

    Probabilities of surface manifestations of liquefaction due to a repeat of the 1868 (M6.7-7.0) earthquake on the southern segment of the Hayward Fault were calculated for two areas along the margin of San Francisco Bay, California: greater Oakland and the northern Santa Clara Valley. Liquefaction is predicted to be more common in the greater Oakland area than in the northern Santa Clara Valley owing to the presence of 57 km2 of susceptible sandy artificial fill. Most of the fills were placed into San Francisco Bay during the first half of the 20th century to build military bases, port facilities, and shoreline communities like Alameda and Bay Farm Island. Probabilities of liquefaction in the area underlain by this sandy artificial fill range from 0.2 to ~0.5 for a M7.0 earthquake, and decrease to 0.1 to ~0.4 for a M6.7 earthquake. In the greater Oakland area, liquefaction probabilities generally are less than 0.05 for Holocene alluvial fan deposits, which underlie most of the remaining flat-lying urban area. In the northern Santa Clara Valley for a M7.0 earthquake on the Hayward Fault and an assumed water-table depth of 1.5 m (the historically shallowest water level), liquefaction probabilities range from 0.1 to 0.2 along Coyote and Guadalupe Creeks, but are less than 0.05 elsewhere. For a M6.7 earthquake, probabilities are greater than 0.1 along Coyote Creek but decrease along Guadalupe Creek to less than 0.1. Areas with high probabilities in the Santa Clara Valley are underlain by young Holocene levee deposits along major drainages where liquefaction and lateral spreading occurred during large earthquakes in 1868 and 1906.

  18. The initial subevent of the 1994 Northridge, California, earthquake: Is earthquake size predictable?

    USGS Publications Warehouse

    Kilb, Debi; Gomberg, J.

    1999-01-01

    We examine the initial subevent (ISE) of the M?? 6.7, 1994 Northridge, California, earthquake in order to discriminate between two end-member rupture initiation models: the 'preslip' and 'cascade' models. Final earthquake size may be predictable from an ISE's seismic signature in the preslip model but not in the cascade model. In the cascade model ISEs are simply small earthquakes that can be described as purely dynamic ruptures. In this model a large earthquake is triggered by smaller earthquakes; there is no size scaling between triggering and triggered events and a variety of stress transfer mechanisms are possible. Alternatively, in the preslip model, a large earthquake nucleates as an aseismically slipping patch in which the patch dimension grows and scales with the earthquake's ultimate size; the byproduct of this loading process is the ISE. In this model, the duration of the ISE signal scales with the ultimate size of the earthquake, suggesting that nucleation and earthquake size are determined by a more predictable, measurable, and organized process. To distinguish between these two end-member models we use short period seismograms recorded by the Southern California Seismic Network. We address questions regarding the similarity in hypocenter locations and focal mechanisms of the ISE and the mainshock. We also compare the ISE's waveform characteristics to those of small earthquakes and to the beginnings of earthquakes with a range of magnitudes. We find that the focal mechanisms of the ISE and mainshock are indistinguishable, and both events may have nucleated on and ruptured the same fault plane. These results satisfy the requirements for both models and thus do not discriminate between them. However, further tests show the ISE's waveform characteristics are similar to those of typical small earthquakes in the vicinity and more importantly, do not scale with the mainshock magnitude. These results are more consistent with the cascade model.

  19. Catastrophic valley fills record large Himalayan earthquakes, Pokhara, Nepal

    NASA Astrophysics Data System (ADS)

    Stolle, Amelie; Bernhardt, Anne; Schwanghart, Wolfgang; Hoelzmann, Philipp; Adhikari, Basanta R.; Fort, Monique; Korup, Oliver

    2017-12-01

    Uncertain timing and magnitudes of past mega-earthquakes continue to confound seismic risk appraisals in the Himalayas. Telltale traces of surface ruptures are rare, while fault trenches document several events at best, so that additional proxies of strong ground motion are needed to complement the paleoseismological record. We study Nepal's Pokhara basin, which has the largest and most extensively dated archive of earthquake-triggered valley fills in the Himalayas. These sediments form a 148-km2 fan that issues from the steep Seti Khola gorge in the Annapurna Massif, invading and plugging 15 tributary valleys with tens of meters of debris, and impounding several lakes. Nearly a dozen new radiocarbon ages corroborate at least three episodes of catastrophic sedimentation on the fan between ∼700 and ∼1700 AD, coinciding with great earthquakes in ∼1100, 1255, and 1344 AD, and emplacing roughly >5 km3 of debris that forms the Pokhara Formation. We offer a first systematic sedimentological study of this formation, revealing four lithofacies characterized by thick sequences of mid-fan fluvial conglomerates, debris-flow beds, and fan-marginal slackwater deposits. New geochemical provenance analyses reveal that these upstream dipping deposits of Higher Himalayan origin contain lenses of locally derived river clasts that mark time gaps between at least three major sediment pulses that buried different parts of the fan. The spatial pattern of 14C dates across the fan and the provenance data are key to distinguishing these individual sediment pulses, as these are not evident from their sedimentology alone. Our study demonstrates how geomorphic and sedimentary evidence of catastrophic valley infill can help to independently verify and augment paleoseismological fault-trench records of great Himalayan earthquakes, while offering unparalleled insights into their long-term geomorphic impacts on major drainage basins.

  20. Groundwater quality in the Santa Clara River Valley, California

    USGS Publications Warehouse

    Burton, Carmen A.; Landon, Matthew K.; Belitz, Kenneth

    2011-01-01

    The Santa Clara River Valley (SCRV) study unit is located in Los Angeles and Ventura Counties, California, and is bounded by the Santa Monica, San Gabriel, Topatopa, and Santa Ynez Mountains, and the Pacific Ocean. The 460-square-mile study unit includes eight groundwater basins: Ojai Valley, Upper Ojai Valley, Ventura River Valley, Santa Clara River Valley, Pleasant Valley, Arroyo Santa Rosa Valley, Las Posas Valley, and Simi Valley (California Department of Water Resources, 2003; Montrella and Belitz, 2009). The SCRV study unit has hot, dry summers and cool, moist winters. Average annual rainfall ranges from 12 to 28 inches. The study unit is drained by the Ventura and Santa Clara Rivers, and Calleguas Creek. The primary aquifer system in the Ventura River Valley, Ojai Valley, Upper Ojai Valley, and Simi Valley basins is largely unconfined alluvium. The primary aquifer system in the remaining groundwater basins mainly consists of unconfined sands and gravels in the upper portion and partially confined marine and nonmarine deposits in the lower portion. The primary aquifer system in the SCRV study unit is defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health (CDPH) database. Public-supply wells typically are completed in the primary aquifer system to depths of 200 to 1,100 feet below land surface (bls). The wells contain solid casing reaching from the land surface to a depth of about 60-700 feet, and are perforated below the solid casing to allow water into the well. Water quality in the primary aquifer system may differ from the water in the shallower and deeper parts of the aquifer. Land use in the study unit is approximately 40 percent (%) natural (primarily shrubs, grassland, and wetlands), 37% agricultural, and 23% urban. The primary crops are citrus, avocados, alfalfa, pasture, strawberries, and dry beans. The largest urban areas in the study unit are the cities of

  1. The Landers earthquake; preliminary instrumental results

    USGS Publications Warehouse

    Jones, L.; Mori, J.; Hauksson, E.

    1992-01-01

    Early on the morning of June 28, 1992, millions of people in southern California were awakened by the largest earthquake to occur in the western United States in the past 40 yrs. At 4:58 a.m PDT (local time), faulting associated with the magnitude 7.3 earthquake broke through to earth's surface near the town of Landers, California. the surface rupture then propagated 70km (45 mi) to the north and northwest along a band of faults passing through the middle of the Mojave Desert. Fortunately, the strongest shaking occurred in uninhabited regions of the Mojave Desert. Still one child was killed in Yucca Valley, and about 400 people were injured in the surrounding area. the desert communities of Landers, Yucca Valley, and Joshua Tree in San Bernardino Country suffered considerable damage to buildings and roads. Damage to water and power lines caused problems in many areas. 

  2. Space Radar Image of Saline Valley, California

    NASA Image and Video Library

    1999-04-15

    This is a three-dimensional perspective view of Saline Valley, about 30 km 19 miles east of the town of Independence, California created by combining two spaceborne radar images using a technique known as interferometry.

  3. Ground water in the San Joaquin Valley, California

    USGS Publications Warehouse

    Kunkel, Fred; Hofman, Walter

    1966-01-01

    Ladies and gentlemen, it is a pleasure to be invited to attend this Irrigation Institute conference and to describe the Geological Survey's program of ground-water studies in the San Joaquin Valley. The U.S. Geological Survey has been making water-resources studies in cooperation with the State of California and other agencies in California for more than 70 years. Three of the earliest Geological Survey Water-Supply Papers--numbers 17, 18, and 19--published in 1898 and 1899, describe "Irrigation near Bakersfield," "Irrigation near Fresno," and "Irrigation near Merced." However, the first Survey report on ground-water occurrence in the San Joaquin Valley was "Ground Water in the San Joaquin Valley," by Mendenhall and others. The fieldwork was done from 1905 to 1910, and the report was published in 1916 as U.S. Geological Survey Water-Supply Paper 398.The current series of ground-water studies in the San Joaquin Valley was begun in 1952 as part of the California Department of Water Resources-U.S. Geological Survey cooperative water-resources program. The first report of this series is Geological Survey Water-Supply Paper 1469, "Ground-Water Conditions and Storage Capacity in the San Joaquin Valley." Other reports are Water-Supply Paper 1618, "Use of Ground-Water Reservoirs for Storage of Surface Water in the San Joaquin Valley;" Water-Supply Paper 1656, "Geology and Ground-Water Features of the Edison-Maricopa Area;" Water-Supply Paper 1360-G, "Ground- Water Conditions in the Mendota-Huron Area;" Water-Supply Paper 1457, "Ground-Water Conditions in the Avenal-McKittrick Area;" and an open-file report, "Geology, Hydrology, and Quality of Water in the Terra Bella-Lost Hills Area."In addition to the preceding published reports, ground-water studies currently are being made of the Kern Fan area, the Hanford- Visalia area, the Fresno area, the Merced area, and of the clays of Tulare Lake. Also, detailed studies of both shallow and deep subsidence in the southern part of

  4. Groundwater quality in the Owens Valley, California

    USGS Publications Warehouse

    Dawson, Barbara J. Milby; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Owens Valley is one of the study areas being evaluated. The Owens study area is approximately 1,030 square miles (2,668 square kilometers) and includes the Owens Valley groundwater basin (California Department of Water Resources, 2003). Owens Valley has a semiarid to arid climate, with average annual rainfall of about 6 inches (15 centimeters). The study area has internal drainage, with runoff primarily from the Sierra Nevada draining east to the Owens River, which flows south to Owens Lake dry lakebed at the southern end of the valley. Beginning in the early 1900s, the City of Los Angeles began diverting the flow of the Owens River to the Los Angeles Aqueduct, resulting in the evaporation of Owens Lake and the formation of the current Owens Lake dry lakebed. Land use in the study area is approximately 94 percent (%) natural, 5% agricultural, and 1% urban. The primary natural land cover is shrubland. The largest urban area is the city of Bishop (2010 population of 4,000). Groundwater in this basin is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from surrounding mountains. Recharge to the groundwater system is primarily runoff from the Sierra Nevada, and by direct infiltration of irrigation. The primary sources of discharge are pumping wells, evapotranspiration, and underflow to the Owens Lake dry lakebed. The primary aquifers in Owens Valley are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database

  5. Response of power systems to the San Fernando Valley earthquake of 9 February 1971. Final report

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schiff, A.J.; Yao, J.T.P.

    1972-01-01

    The impact of the San Fernando Valley earthquake on electric power systems is discussed. Particular attention focused on the following three areas; (1) the effects of an earthquake on the power network in the Western States, (2) the failure of subsystems and components of the power system, and (3) the loss of power to hospitals. The report includes sections on the description and functions of major components of a power network, existing procedures to protect the network, safety devices within the system which influence the network, a summary of the effects of the San Fernando Valley earthquake on the Westernmore » States Power Network, and present efforts to reduce the network vulnerability to faults. Also included in the report are a review of design procedures and practices prior to the San Fernando Valley earthquake and descriptions of types of damage to electrical equipment, dynamic analysis of equipment failures, equipment surviving the San Fernando Valley earthquake and new seismic design specifications. In addition, some observations and insights gained during the study, which are not directly related to power systems are discussed.« less

  6. 78 FR 45114 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-26

    ... the California State Implementation Plan, Antelope Valley Air Quality Management District AGENCY... the Antelope Valley Air Quality Management District (AVAQMD) portion of the California State... for the South Coast Air Quality Management District (SCAQMD). The Antelope Valley Air Pollution...

  7. Map of the Rinconada and Reliz Fault Zones, Salinas River Valley, California

    USGS Publications Warehouse

    Rosenberg, Lewis I.; Clark, Joseph C.

    2009-01-01

    The Rinconada Fault and its related faults constitute a major structural element of the Salinas River valley, which is known regionally, and referred to herein, as the 'Salinas Valley'. The Rinconada Fault extends 230 km from King City in the north to the Big Pine Fault in the south. At the south end of the map area near Santa Margarita, the Rinconada Fault separates granitic and metamorphic crystalline rocks of the Salinian Block to the northeast from the subduction-zone assemblage of the Franciscan Complex to the southwest. Northwestward, the Rinconada Fault lies entirely within the Salinian Block and generally divides this region into two physiographically and structurally distinct areas, the Santa Lucia Range to the west and the Salinas Valley to the east. The Reliz Fault, which continues as a right stepover from the Rinconada Fault, trends northwestward along the northeastern base of the Sierra de Salinas of the Santa Lucia Range and beyond for 60 km to the vicinity of Spreckels, where it is largely concealed. Aeromagnetic data suggest that the Reliz Fault continues northwestward another 25 km into Monterey Bay, where it aligns with a high-definition magnetic boundary. Geomorphic evidence of late Quaternary movement along the Rinconada and Reliz Fault Zones has been documented by Tinsley (1975), Dibblee (1976, 1979), Hart (1976, 1985), and Klaus (1999). Although definitive geologic evidence of Holocene surface rupture has not been found on these faults, they were regarded as an earthquake source for the California Geological Survey [formerly, California Division of Mines and Geology]/U.S. Geological Survey (CGS/USGS) Probabilistic Seismic Hazards Assessment because of their postulated slip rate of 1+-1 mm/yr and their calculated maximum magnitude of 7.3. Except for published reports by Durham (1965, 1974), Dibblee (1976), and Hart (1976), most information on these faults is unpublished or is contained in theses, field trip guides, and other types of reports

  8. SCIGN; new Southern California GPS network advances the study of earthquakes

    USGS Publications Warehouse

    Hudnut, Ken; King, Nancy

    2001-01-01

    Southern California is a giant jigsaw puzzle, and scientists are now using GPS satellites to track the pieces. These puzzle pieces are continuously moving, slowly straining the faults in between. That strain is then eventually released in earthquakes. The innovative Southern California Integrated GPS Network (SCIGN) tracks the motions of these pieces over most of southern California with unprecedented precision. This new network greatly improves the ability to assess seismic hazards and quickly measure the larger displacements that occur during and immediatelyafter earthquakes.

  9. The Long Valley Caldera GIS database

    USGS Publications Warehouse

    Battaglia, Maurizio; Williams, M.J.; Venezky, D.Y.; Hill, D.P.; Langbein, J.O.; Farrar, C.D.; Howle, J.F.; Sneed, M.; Segall, P.

    2003-01-01

    This database provides an overview of the studies being conducted by the Long Valley Observatory in eastern California from 1975 to 2001. The database includes geologic, monitoring, and topographic datasets related to Long Valley caldera. The CD-ROM contains a scan of the original geologic map of the Long Valley region by R. Bailey. Real-time data of the current activity of the caldera (including earthquakes, ground deformation and the release of volcanic gas), information about volcanic hazards and the USGS response plan are available online at the Long Valley observatory web page (http://lvo.wr.usgs.gov). If you have any comments or questions about this database, please contact the Scientist in Charge of the Long Valley observatory.

  10. Seismic calibration shots conducted in 2009 in the Imperial Valley, southern California, for the Salton Seismic Imaging Project (SSIP)

    USGS Publications Warehouse

    Murphy, Janice; Goldman, Mark; Fuis, Gary; Rymer, Michael; Sickler, Robert; Miller, Summer; Butcher, Lesley; Ricketts, Jason; Criley, Coyn; Stock, Joann; Hole, John; Chavez, Greg

    2011-01-01

    Rupture of the southern section of the San Andreas Fault, from the Coachella Valley to the Mojave Desert, is believed to be the greatest natural hazard facing California in the near future. With an estimated magnitude between 7.2 and 8.1, such an event would result in violent shaking, loss of life, and disruption of lifelines (freeways, aqueducts, power, petroleum, and communication lines) that would bring much of southern California to a standstill. As part of the Nation's efforts to prevent a catastrophe of this magnitude, a number of projects are underway to increase our knowledge of Earth processes in the area and to mitigate the effects of such an event. One such project is the Salton Seismic Imaging Project (SSIP), which is a collaborative venture between the United States Geological Survey (USGS), California Institute of Technology (Caltech), and Virginia Polytechnic Institute and State University (Virginia Tech). This project will generate and record seismic waves that travel through the crust and upper mantle of the Salton Trough. With these data, we will construct seismic images of the subsurface, both reflection and tomographic images. These images will contribute to the earthquake-hazard assessment in southern California by helping to constrain fault locations, sedimentary basin thickness and geometry, and sedimentary seismic velocity distributions. Data acquisition is currently scheduled for winter and spring of 2011. The design and goals of SSIP resemble those of the Los Angeles Region Seismic Experiment (LARSE) of the 1990's. LARSE focused on examining the San Andreas Fault system and associated thrust-fault systems of the Transverse Ranges. LARSE was successful in constraining the geometry of the San Andreas Fault at depth and in relating this geometry to mid-crustal, flower-structure-like decollements in the Transverse Ranges that splay upward into the network of hazardous thrust faults that caused the 1971 M 6.7 San Fernando and 1987 M 5

  11. The 1954 Rainbow Mountain-Fairview Peak-Dixie Valley earthquakes: A triggered normal faulting sequence

    NASA Astrophysics Data System (ADS)

    Hodgkinson, Kathleen M.; Stein, Ross S.; King, Geoffrey C. P.

    1996-11-01

    In 1954, four earthquakes of M > 6.0 occurred within a 30 km radius in a period of six months. The Rainbow Mountain-Fairview Peak-Dixie Valley earthquakes are among the largest to have been recorded geodetically in the Basin and Range province. The Fairview Peak earthquake (M = 7.2, December 12, 1954) followed two events in the Rainbow Mountains (M = 6.2, July 6, and M = 6.5, August 24, 1954) by 6 months. Four minutes later the Dixie Valley fault ruptured (M = 6.7, December 12, 1954). The changes in static stresses caused by the events are calculated using the Coulomb-Navier failure criterion and assuming uniform slip on rectangular dislocations embedded in an elastic half-space. Coulomb stress changes are resolved on optimally oriented faults and on each of the faults that ruptured in the chain of events. These calculations show that each earthquake in the Rainbow Mountain-Fairview Peak-Dixie Valley sequence was preceded by a static stress change that encouraged failure. The magnitude of the stress increases transferred from one earthquake to another ranged from 0.01 MPa (0.1 bar) to over 0.1 MPa (1 bar). Stresses were reduced by up to 0.1 MPa over most of the Rainbow Mountain-Fairview Peak area as a result of the earthquake sequence.

  12. The 1954 Rainbow Mountain-Fairview Peak-Dixie Valley earthquakes: A triggered normal faulting sequence

    USGS Publications Warehouse

    Hodgkinson, K.M.; Stein, R.S.; King, G.C.P.

    1996-01-01

    In 1954, four earthquakes of M > 6.0 occurred within a 30 km radius in a period of six months. The Rainbow Mountain-Fairview Peak-Dixie Valley earthquakes are among the largest to have been recorded geodetically in the Basin and Range province. The Fairview Peak earthquake (M=7.2, December 12, 1954) followed two events in the Rainbow Mountains (M=6.2, July 6, and M=6.5, August 24, 1954) by 6 months. Four minutes later the Dixie Valley fault ruptured (M=6.7, December 12, 1954). The changes in static stresses caused by the events are calculated using the Coulomb-Navier failure criterion and assuming uniform slip on rectangular dislocations embedded in an elastic half-space. Coulomb stress changes are resolved on optimally oriented faults and on each of the faults that ruptured in the chain of events. These calculations show that each earthquake in the Rainbow Mountain-Fairview Peak-Dixie Valley sequence was preceded by a static stress change that encouraged failure. The magnitude of the stress increases transferred from one earthquake to another ranged from 0.01 MPa (0.1 bar) to over 0.1 MPa (1 bar). Stresses were reduced by up to 0.1 MPa over most of the Rainbow Mountain-Fairview Peak area as a result of the earthquake sequence. Copyright 1996 by the American Geophysical Union.

  13. Nowcasting Earthquakes: A Comparison of Induced Earthquakes in Oklahoma and at the Geysers, California

    NASA Astrophysics Data System (ADS)

    Luginbuhl, Molly; Rundle, John B.; Hawkins, Angela; Turcotte, Donald L.

    2018-01-01

    Nowcasting is a new method of statistically classifying seismicity and seismic risk (Rundle et al. 2016). In this paper, the method is applied to the induced seismicity at the Geysers geothermal region in California and the induced seismicity due to fluid injection in Oklahoma. Nowcasting utilizes the catalogs of seismicity in these regions. Two earthquake magnitudes are selected, one large say M_{λ } ≥ 4, and one small say M_{σ } ≥ 2. The method utilizes the number of small earthquakes that occurs between pairs of large earthquakes. The cumulative probability distribution of these values is obtained. The earthquake potential score (EPS) is defined by the number of small earthquakes that has occurred since the last large earthquake, the point where this number falls on the cumulative probability distribution of interevent counts defines the EPS. A major advantage of nowcasting is that it utilizes "natural time", earthquake counts, between events rather than clock time. Thus, it is not necessary to decluster aftershocks and the results are applicable if the level of induced seismicity varies in time. The application of natural time to the accumulation of the seismic hazard depends on the applicability of Gutenberg-Richter (GR) scaling. The increasing number of small earthquakes that occur after a large earthquake can be scaled to give the risk of a large earthquake occurring. To illustrate our approach, we utilize the number of M_{σ } ≥ 2.75 earthquakes in Oklahoma to nowcast the number of M_{λ } ≥ 4.0 earthquakes in Oklahoma. The applicability of the scaling is illustrated during the rapid build-up of injection-induced seismicity between 2012 and 2016, and the subsequent reduction in seismicity associated with a reduction in fluid injections. The same method is applied to the geothermal-induced seismicity at the Geysers, California, for comparison.

  14. Death Valley, California

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is an image of Death Valley, California, centered at 36.629 degrees north latitude, 117.069 degrees west longitude. The image shows Furnace Creek alluvial fan and Furnace Creek Ranch at the far right, and the sand dunes near Stove Pipe Wells at the center. The dark fork-shaped feature between Furnace Creek fan and the dunes is a smooth flood-plain which encloses Cottonball Basin. The bright dots near the center of the image are corner refectors that have been set-up to calibrate the radar as the Shuttle passes overhead with the SIR-C/X-SAR system. The Jet Propulsion Laboratory alternative photo number is P-43883.

  15. Liquefaction sites, Imperial Valley, California.

    USGS Publications Warehouse

    Youd, T.L.; Bennett, M.J.

    1983-01-01

    Sands that did and did not liquefy at two sites during the 1979 Imperial Valley, Calif., earthquake (ML = 6.6) are identified and their properties evaluated. SPT tests were used to evaluate liquefaction susceptibility. Loose fine sands in an abandoned channel liquefied and produced sand boils, ground fissures, and a lateral spread at the Heber Road sites. Evidence of liquefaction was not observed over moderately dense over-bank sand east of the channel nor over dense point-bar sand to the west. -from ASCE Publications Information

  16. Pattern of ground deformation in Kathmandu valley during 2015 Gorkha Earthquake, central Nepal

    NASA Astrophysics Data System (ADS)

    Ghimire, S.; Dwivedi, S. K.; Acharya, K. K.

    2016-12-01

    The 25th April 2015 Gorkha Earthquake (Mw=7.8) epicentered at Barpak along with thousands of aftershocks released seismic moment nearly equivalent to an 8.0 Magnitude earthquake rupturing a 150km long fault segment. Although Kathmandu valley was supposed to be severely devastated by such major earthquake, post earthquake scenario is completely different. The observed destruction is far less than anticipated as well as the spatial pattern is different than expected. This work focuses on the behavior of Kathmandu valley sediments during the strong shaking by the 2015 Gorkha Earthquake. For this purpose spatial pattern of destruction is analyzed at heavily destructed sites. To understand characteristics of subsurface soil 2D-MASW survey was carried out using a 24-channel seismograph system. An accellerogram recorded by Nepal Seismological Center was analyzed to characterize the strong ground motion. The Kathmandu valley comprises fluvio-lacustrine deposit with gravel, sand, silt and clay along with few exposures of basement rocks within the sediments. The observations show systematic repetition of destruction at an average interval of 2.5km mostly in sand, silt and clay dominated formations. Results of 2D-MASW show the sites of destruction are characterized by static deformation of soil (liquefaction and southerly dipping cracks). Spectral analysis of the accelerogram indicates maximum power associated with frequency of 1.0Hz. The result of this study explains the observed spatial pattern of destruction in Kathmandu valley. This is correlated with the seismic energy associated with the frequency of 1Hz, which generates an average wavelength of 2.5km with an average S-wave velocity of 2.5km/s. The cumulative effect of dominant frequency and associated wavelength resulted in static deformation of surface soil layers at an average interval of 2.5km. This phenomenon clearly describes the reason for different scenario than that was anticipated in Kathmandu valley.

  17. In the shadow of 1857-the effect of the great Ft. Tejon earthquake on subsequent earthquakes in southern California

    USGS Publications Warehouse

    Harris, R.A.; Simpson, R.W.

    1996-01-01

    The great 1857 Fort Tejon earthquake is the largest earthquake to have hit southern California during the historic period. We investigated if seismicity patterns following 1857 could be due to static stress changes generated by the 1857 earthquake. When post-1857 earthquakes with unknown focal mechanisms were assigned strike-slip mechanisms with strike and rake determined by the nearest active fault, 13 of the 13 southern California M???5.5 earthquakes between 1857 and 1907 were encouraged by the 1857 rupture. When post-1857 earthquakes in the Transverse Ranges with unknown focal mechanisms were assigned reverse mechanisms and all other events were assumed strike-slip, 11 of the 13 earthquakes were encouraged by the 1857 earthquake. These results show significant correlations between static stress changes and seismicity patterns. The correlation disappears around 1907, suggesting that tectonic loading began to overwhelm the effect of the 1857 earthquake early in the 20th century.

  18. Groundwater quality in the Northern Sacramento Valley, California

    USGS Publications Warehouse

    Bennett, George L.; Fram, Miranda S.; Belitz, Kenneth

    2011-01-01

    Groundwater provides more than 40 percent of California's drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State's groundwater quality and increases public access to groundwater-quality information. The Northern Sacramento Valley is one of the study units being evaluated.

  19. Groundwater quality in the Southern Sacramento Valley, California

    USGS Publications Warehouse

    Bennett, George L.; Fram, Miranda S.; Belitz, Kenneth

    2011-01-01

    Groundwater provides more than 40 percent of California's drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State's groundwater quality and increases public access to groundwater-quality information. The Southern Sacramento Valley is one of the study units being evaluated.

  20. Catalog of earthquakes along the San Andreas fault system in Central California, July-September 1972

    USGS Publications Warehouse

    Wesson, R.L.; Meagher, K.L.; Lester, F.W.

    1973-01-01

    Numerous small earthquakes occur each day in the coast ranges of Central California. The detailed study of these earthquakes provides a tool for gaining insight into the tectonic and physical processes responsible for the generation of damaging earthquakes. This catalog contains the fundamental parameters for earthquakes located within and adjacent to the seismograph network operated by the National Center for Earthquake Research (NCER), U.S. Geological Survey, during the period July - September, 1972. The motivation for these detailed studies has been described by Pakiser and others (1969) and by Eaton and others (1970). Similar catalogs of earthquakes for the years 1969, 1970 and 1971 have been prepared by Lee and others (1972 b, c, d). Catalogs for the first and second quarters of 1972 have been prepared by Wessan and others (1972 a & b). The basic data contained in these catalogs provide a foundation for further studies. This catalog contains data on 1254 earthquakes in Central California. Arrival times at 129 seismograph stations were used to locate the earthquakes listed in this catalog. Of these, 104 are telemetered stations operated by NCER. Readings from the remaining 25 stations were obtained through the courtesy of the Seismographic Stations, University of California, Berkeley (UCB), the Earthquake Mechanism Laboratory, National Oceanic and Atmospheric Administration, San Francisco (EML); and the California Department of Water Resources, Sacramento. The Seismographic Stations of the University of California, Berkeley, have for many years published a bulletin describing earthquakes in Northern California and the surrounding area, and readings at UCB Stations from more distant events. The purpose of the present catalog is not to replace the UCB Bulletin, but rather to supplement it, by describing the seismicity of a portion of central California in much greater detail.

  1. How does the 2010 El Mayor - Cucapah Earthquake Rupture Connect to the Southern California Plate Boundary Fault System

    NASA Astrophysics Data System (ADS)

    Donnellan, A.; Ben-Zion, Y.; Arrowsmith, R.

    2016-12-01

    The Pacific - North American plate boundary in southern California is marked by several major strike slip faults. The 2010 M7.2 El Mayor - Cucapah earthquake ruptured 120 km of upper crust in Baja California to the US-Mexico border. The earthquake triggered slip along an extensive network of faults in the Salton Trough from the Mexican border to the southern end of the San Andreas fault. Earthquakes >M5 were triggered in the gap between the Laguna Salada and Elsinore faults at Ocotillo and on the Coyote Creek segment of the San Jacinto fault 20 km northwest of Borrego Springs. UAVSAR observations, collected since October of 2009, measure slip associated with the M5.7 Ocotillo aftershock with deformation continuing into 2014. The Elsinore fault has been remarkably quiet, however, with only M5.0 and M5.2 earthquakes occurring on the Coyote Mountains segment of the fault in 1940 and 1968 respectively. In contrast, the Imperial Valley has been quite active historically with numerous moderate events occurring since 1935. Moderate event activity is increasing along the San Jacinto fault zone (SJFZ), especially the trifurcation area, where 6 of 12 historic earthquakes in this 20 km long fault zone have occurred since 2000. However, no recent deformation has been detected using UAVSAR measurements in this area, including the recent M5.2 June 2016 Borrego earthquake. Does the El Mayor - Cucapah rupture connect to and transfer stress primarily to a single southern California fault or several? What is its role relative to the background plate motion? UAVSAR observations indicate that the southward extension of the Elsinore fault has recently experienced the most localized deformation. Seismicity suggests that the San Jacinto fault is more active than neighboring major faults, and geologic evidence suggests that the Southern San Andreas fault has been the major plate boundary fault in southern California. Topographic data with 3-4 cm resolution using structure from motion from

  2. Riparian valley oak (Quercus lobata) forest restoration on the middle Sacramento River, California

    Treesearch

    F. Thomas Griggs; Gregory H. Golet

    2002-01-01

    In 1989 The Nature Conservancy initiated a riparian horticultural restoration program on the floodplain of the middle Sacramento River, California. At nearly all restoration sites Valley oak (Quercus lobata Nee) comprised a major component of the planting design. Valley oaks are a keystone tree species of lowland floodplain habitats in California...

  3. Automatic 3D Moment tensor inversions for southern California earthquakes

    NASA Astrophysics Data System (ADS)

    Liu, Q.; Tape, C.; Friberg, P.; Tromp, J.

    2008-12-01

    We present a new source mechanism (moment-tensor and depth) catalog for about 150 recent southern California earthquakes with Mw ≥ 3.5. We carefully select the initial solutions from a few available earthquake catalogs as well as our own preliminary 3D moment tensor inversion results. We pick useful data windows by assessing the quality of fits between the data and synthetics using an automatic windowing package FLEXWIN (Maggi et al 2008). We compute the source Fréchet derivatives of moment-tensor elements and depth for a recent 3D southern California velocity model inverted based upon finite-frequency event kernels calculated by the adjoint methods and a nonlinear conjugate gradient technique with subspace preconditioning (Tape et al 2008). We then invert for the source mechanisms and event depths based upon the techniques introduced by Liu et al 2005. We assess the quality of this new catalog, as well as the other existing ones, by computing the 3D synthetics for the updated 3D southern California model. We also plan to implement the moment-tensor inversion methods to automatically determine the source mechanisms for earthquakes with Mw ≥ 3.5 in southern California.

  4. Probability of one or more M ≥7 earthquakes in southern California in 30 years

    USGS Publications Warehouse

    Savage, J.C.

    1994-01-01

    Eight earthquakes of magnitude greater than or equal to seven have occurred in southern California in the past 200 years. If one assumes that such events are the product of a Poisson process, the probability of one or more earthquakes of magnitude seven or larger in southern California within any 30 year interval is 67% ?? 23% (95% confidence interval). Because five of the eight M ??? 7 earthquakes in southern California in the last 200 years occurred away from the San Andreas fault system, the probability of one or more M ??? 7 earthquakes in southern California but not on the San Andreas fault system occurring within 30 years is 52% ?? 27% (95% confidence interval). -Author

  5. Late Quaternary faulting along the Death Valley-Furnace Creek fault system, California and Nevada

    USGS Publications Warehouse

    Brogan, George E.; Kellogg, Karl; Slemmons, D. Burton; Terhune, Christina L.

    1991-01-01

    The Death Valley-Furnace Creek fault system, in California and Nevada, has a variety of impressive late Quaternary neotectonic features that record a long history of recurrent earthquake-induced faulting. Although no neotectonic features of unequivocal historical age are known, paleoseismic features from multiple late Quaternary events of surface faulting are well developed throughout the length of the system. Comparison of scarp heights to amount of horizontal offset of stream channels and the relationships of both scarps and channels to the ages of different geomorphic surfaces demonstrate that Quaternary faulting along the northwest-trending Furnace Creek fault zone is predominantly right lateral, whereas that along the north-trending Death Valley fault zone is predominantly normal. These observations are compatible with tectonic models of Death Valley as a northwest-trending pull-apart basin. The largest late Quaternary scarps along the Furnace Creek fault zone, with vertical separation of late Pleistocene surfaces of as much as 64 m (meters), are in Fish Lake Valley. Despite the predominance of normal faulting along the Death Valley fault zone, vertical offset of late Pleistocene surfaces along the Death Valley fault zone apparently does not exceed about 15 m. Evidence for four to six separate late Holocene faulting events along the Furnace Creek fault zone and three or more late Holocene events along the Death Valley fault zone are indicated by rupturing of Q1B (about 200-2,000 years old) geomorphic surfaces. Probably the youngest neotectonic feature observed along the Death Valley-Furnace Creek fault system, possibly historic in age, is vegetation lineaments in southernmost Fish Lake Valley. Near-historic faulting in Death Valley, within several kilometers south of Furnace Creek Ranch, is represented by (1) a 2,000-year-old lake shoreline that is cut by sinuous scarps, and (2) a system of young scarps with free-faceted faces (representing several faulting

  6. Distribution and Characteristics of Repeating Earthquakes in Northern California

    NASA Astrophysics Data System (ADS)

    Waldhauser, F.; Schaff, D. P.; Zechar, J. D.; Shaw, B. E.

    2012-12-01

    Repeating earthquakes are playing an increasingly important role in the study of fault processes and behavior, and have the potential to improve hazard assessment, earthquake forecast, and seismic monitoring capabilities. These events rupture the same fault patch repeatedly, generating virtually identical seismograms. In California, repeating earthquakes have been found predominately along the creeping section of the central San Andreas Fault, where they are believed to represent failing asperities on an otherwise creeping fault. Here, we use the northern California double-difference catalog of 450,000 precisely located events (1984-2009) and associated database of 2 billion waveform cross-correlation measurements to systematically search for repeating earthquakes across various tectonic regions. An initial search for pairs of earthquakes with high-correlation coefficients and similar magnitudes resulted in 4,610 clusters including a total of over 26,000 earthquakes. A subsequent double-difference re-analysis of these clusters resulted in 1,879 sequences (8,640 events) where a common rupture area can be resolved to the precision of a few tens of meters or less. These repeating earthquake sequences (RES) include between 3 and 24 events with magnitudes up to ML=4. We compute precise relative magnitudes between events in each sequence from differential amplitude measurements. Differences between these and standard coda-duration magnitudes have a standard deviation of 0.09. The RES occur throughout northern California, but RES with 10 or more events (6%) only occur along the central San Andreas and Calaveras faults. We are establishing baseline characteristics for each sequence, such as recurrence intervals and their coefficient of variation (CV), in order to compare them across tectonic regions. CVs for these clusters range from 0.002 to 2.6, indicating a range of behavior between periodic occurrence (CV~0), random occurrence, and temporal clustering. 10% of the RES

  7. Moderate rates of late Quaternary slip along the northwestern margin of the Basin and Range Province, Surprise Valley fault, northeastern California

    USGS Publications Warehouse

    Personius, Stephen F.; Crone, Anthony J.; Machette, Michael N.; Mahan, Shannon; Lidke, David J.

    2009-01-01

    The 86-km-long Surprise Valley normal fault forms part of the active northwestern margin of the Basin and Range province in northeastern California. We use trench mapping and radiocarbon, luminescence, and tephra dating to estimate displacements and timing of the past five surface-rupturing earthquakes on the central part of the fault near Cedarville. A Bayesian OxCal analysis of timing constraints indicates earthquake times of 18.2 ± 2.6, 10.9 ± 3.2, 8.5 ± 0.5, 5.8 ± 1.5, and 1.2 ± 0.1 ka. These data yield recurrence intervals of 7.3 ± 4.1, 2.5 ± 3.2, 2.7 ± 1.6, and 4.5 ± 1.5 ka and an elapsed time of 1.2 ± 0.1 ka since the latest surface-rupturing earthquake. Our best estimate of latest Quaternary vertical slip rate is 0.6 ?? 0.1 mm/a. This late Quaternary rate is remarkably similar to long-term (8-14 Ma) minimum vertical slip rates (>0.4-0.5 ± 0.3 mm/a) calculated from recently acquired seismic reflection and chronologic and structural data in Surprise Valley and the adjacent Warner Mountains. However, our slip rate yields estimates of extension that are lower than recent campaign GPS determinations by factors of 1.5-4 unless the fault has an unusually shallow (30°-35°) dip as suggested by recently acquired seismic reflection data. Coseismic displacements of 2-4.5 ± 1 m documented in the trench and probable rupture lengths of 53-65 km indicate a history of latest Quaternary earthquakes of M 6.8-7.3 on the central part of the. Surprise Valley fault.

  8. Microscopic Identification of Prokaryotes in Modern and Ancient Halite, Saline Valley and Death Valley, California

    NASA Astrophysics Data System (ADS)

    Schubert, Brian A.; Lowenstein, Tim K.; Timofeeff, Michael N.

    2009-06-01

    Primary fluid inclusions in halite crystallized in Saline Valley, California, in 1980, 2004-2005, and 2007, contain rod- and coccoid-shaped microparticles the same size and morphology as archaea and bacteria living in modern brines. Primary fluid inclusions from a well-dated (0-100,000 years), 90 m long salt core from Badwater Basin, Death Valley, California, also contain microparticles, here interpreted as halophilic and halotolerant prokaryotes. Prokaryotes are distinguished from crystals on the basis of morphology, optical properties (birefringence), and uniformity of size. Electron micrographs of microparticles from filtered modern brine (Saline Valley), dissolved modern halite crystals (Saline Valley), and dissolved ancient halite crystals (Death Valley) support in situ microscopic observations that prokaryotes are present in fluid inclusions in ancient halite. In the Death Valley salt core, prokaryotes in fluid inclusions occur almost exclusively in halite precipitated in perennial saline lakes 10,000 to 35,000 years ago. This suggests that trapping and preservation of prokaryotes in fluid inclusions is influenced by the surface environment in which the halite originally precipitated. In all cases, prokaryotes in fluid inclusions in halite from the Death Valley salt core are miniaturized (<1 μm diameter cocci, <2.5 μm long, very rare rod shapes), which supports interpretations that the prokaryotes are indigenous to the halite and starvation survival may be the normal response of some prokaryotes to entrapment in fluid inclusions for millennia. These results reinforce the view that fluid inclusions in halite and possibly other evaporites are important repositories of microbial life and should be carefully examined in the search for ancient microorganisms on Earth, Mars, and elsewhere in the Solar System.

  9. Sutter Buttes-the lone volcano in California's Great Valley

    USGS Publications Warehouse

    Hausback, Brain P.; Muffler, L.J. Patrick; Clynne, Michael A.

    2011-01-01

    The volcanic spires of the Sutter Buttes tower 2,000 feet above the farms and fields of California's Great Valley, just 50 miles north-northwest of Sacramento and 11 miles northwest of Yuba City. The only volcano within the valley, the Buttes consist of a central core of volcanic domes surrounded by a large apron of fragmental volcanic debris. Eruptions at the Sutter Buttes occurred in early Pleistocene time, 1.6 to 1.4 million years ago. The Sutter Buttes are not part of the Cascade Range of volcanoes to the north, but instead are related to the volcanoes in the Coast Ranges to the west in the vicinity of Clear Lake, Napa Valley, and Sonoma Valley.

  10. Forecasting California's earthquakes: What can we expect in the next 30 years?

    USGS Publications Warehouse

    Field, Edward H.; Milner, Kevin R.; ,

    2008-01-01

    In a new comprehensive study, scientists have determined that the chance of having one or more magnitude 6.7 or larger earthquakes in the California area over the next 30 years is greater than 99%. Such quakes can be deadly, as shown by the 1989 magnitude 6.9 Loma Prieta and the 1994 magnitude 6.7 Northridge earthquakes. The likelihood of at least one even more powerful quake of magnitude 7.5 or greater in the next 30 years is 46%?such a quake is most likely to occur in the southern half of the State. Building codes, earthquake insurance, and emergency planning will be affected by these new results, which highlight the urgency to prepare now for the powerful quakes that are inevitable in California?s future.

  11. 76 FR 38589 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 52 [EPA-R09-OAR-2011-0383; FRL-9428-1] Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management District AGENCY... the Antelope Valley Air Quality Management District (AVAQMD) portion of the California State...

  12. Neogene contraction between the San Andreas fault and the Santa Clara Valley, San Francisco Bay region, California

    USGS Publications Warehouse

    McLaughlin, R.J.; Langenheim, V.E.; Schmidt, K.M.; Jachens, R.C.; Stanley, R.G.; Jayko, A.S.; McDougall, K.A.; Tinsley, J.C.; Valin, Z.C.

    1999-01-01

    In the southern San Francisco Bay region of California, oblique dextral reverse faults that verge northeastward from the San Andreas fault experienced triggered slip during the 1989 M7.1 Loma Prieta earthquake. The role of these range-front thrusts in the evolution of the San Andreas fault system and the future seismic hazard that they may pose to the urban Santa Clara Valley are poorly understood. Based on recent geologic mapping and geophysical investigations, we propose that the range-front thrust system evolved in conjunction with development of the San Andreas fault system. In the early Miocene, the region was dominated by a system of northwestwardly propagating, basin-bounding, transtensional faults. Beginning as early as middle Miocene time, however, the transtensional faulting was superseded by transpressional NE-stepping thrust and reverse faults of the range-front thrust system. Age constraints on the thrust faults indicate that the locus of contraction has focused on the Monte Vista, Shannon, and Berrocal faults since about 4.8 Ma. Fault slip and fold reconstructions suggest that crustal shortening between the San Andreas fault and the Santa Clara Valley within this time frame is ~21%, amounting to as much as 3.2 km at a rate of 0.6 mm/yr. Rates probably have not remained constant; average rates appear to have been much lower in the past few 100 ka. The distribution of coseismic surface contraction during the Loma Prieta earthquake, active seismicity, late Pleistocene to Holocene fluvial terrace warping, and geodetic data further suggest that the active range-front thrust system includes blind thrusts. Critical unresolved issues include information on the near-surface locations of buried thrusts, the timing of recent thrust earthquake events, and their recurrence in relation to earthquakes on the San Andreas fault.

  13. Sedimentary record of the 1872 earthquake and "Tsunami" at Owens Lake, southeast California

    USGS Publications Warehouse

    Smoot, J.P.; Litwin, R.J.; Bischoff, J.L.; Lund, S.J.

    2000-01-01

    In 1872, a magnitude 7.5-7.7 earthquake vertically offset the Owens Valley fault by more than a meter. An eyewitness reported a large wave on the surface of Owens Lake, presumably initiated by the earthquake. Physical evidence of this event is found in cores and trenches from Owens Lake, including soft-sediment deformation and fault offsets. A graded pebbly sand truncates these features, possibly over most of the lake floor, reflecting the "tsunami" wave. Confirmation of the timing of the event is provided by abnormally high lead concentrations in the sediment immediately above and below these proposed earthquake deposits derived from lead-smelting plants that operated near the eastern lake margin from 1869-1876. The bottom velocity in the deepest part of the lake needed to transport the coarsest grain sizes in the graded pebbly sand provides an estimate of the minimum initial 'tsunami' wave height at 37 cm. This is less than the wave height calculated from long-wave numerical models (about 55 cm) using average fault displacement during the earthquake. Two other graded sand deposits associated with soft-sediment deformation in the Owens Lake record are less than 3000 years old, and are interpreted as evidence of older earthquake and tsunami events. Offsets of the Owens Valley fault elsewhere in the valley indicate that at least two additional large earthquakes occurred during the Holocene, which is consistent with our observations in this lacustrine record.

  14. Inventory of landslides triggered by the 1994 Northridge, California earthquake

    USGS Publications Warehouse

    Harp, Edwin L.; Jibson, Randall W.

    1995-01-01

    The 17 January 1994 Northridge, California, earthquake (M=6.7) triggered more than 11,000 landslides over an area of about 10,000 km?. Most of the landslides were concentrated in a 1,000-km? area that includes the Santa Susana Mountains and the mountains north of the Santa Clara River valley. We mapped landslides triggered by the earthquake in the field and from 1:60,000-scale aerial photography provided by the U.S. Air Force and taken the morning of the earthquake; these were subsequently digitized and plotted in a GIS-based format, as shown on the accompanying maps (which also are accessible via Internet). Most of the triggered landslides were shallow (1-5 m), highly disrupted falls and slides in weakly cemented Tertiary to Pleistocene clastic sediment. Average volumes of these types of landslides were less than 1,000 m?, but many had volumes exceeding 100,000 m?. Many of the larger disrupted slides traveled more than 50 m, and a few moved as far as 200 m from the bases of steep parent slopes. Deeper ( >5 m) rotational slumps and block slides numbered in the hundreds, a few of which exceeded 100,000 m? in volume. The largest triggered landslide was a block slide having a volume of 8X10E06 m?. Triggered landslides damaged or destroyed dozens of homes, blocked roads, and damaged oil-field infrastructure. Analysis of landslide distribution with respect to variations in (1) landslide susceptibility and (2) strong shaking recorded by hundreds of instruments will form the basis of a seismic landslide hazard analysis of the Los Angeles area.

  15. Death Valley California as seen from STS-59

    NASA Image and Video Library

    1994-04-13

    STS059-86-059 (9-20 April 1994) --- This oblique handheld Hasselblad 70mm photo shows Death Valley, near California's border with Nevada. The valley -- the central feature of Death Valley National Monument -- extends north to south for some 140 miles (225 kilometers). Hemmed in to the east by the Amargosa Range and to the west by the Panamints, its width varies from 5 to 15 miles (8 to 24 kilometers). Using Spaceborne Imaging Radar (SIR-C) and X-band Synthetic Aperture Radar (X-SAR) onboard the Space Shuttle Endeavour, the crew was able to record a great deal of data on this and other sites, as part of NASA's Mission to Planet Earth.

  16. The California Post-Earthquake Information Clearinghouse: A Plan to Learn From the Next Large California Earthquake

    NASA Astrophysics Data System (ADS)

    Loyd, R.; Walter, S.; Fenton, J.; Tubbesing, S.; Greene, M.

    2008-12-01

    In the rush to remove debris after a damaging earthquake, perishable data related to a wide range of impacts on the physical, built and social environments can be lost. The California Post-Earthquake Information Clearinghouse is intended to prevent this data loss by supporting the earth scientists, engineers, and social and policy researchers who will conduct fieldwork in the affected areas in the hours and days following the earthquake to study these effects. First called for by Governor Ronald Reagan following the destructive M6.5 San Fernando earthquake in 1971, the concept of the Clearinghouse has since been incorporated into the response plans of the National Earthquake Hazard Reduction Program (USGS Circular 1242). This presentation is intended to acquaint scientists with the purpose, functions, and services of the Clearinghouse. Typically, the Clearinghouse is set up in the vicinity of the earthquake within 24 hours of the mainshock and is maintained for several days to several weeks. It provides a location where field researchers can assemble to share and discuss their observations, plan and coordinate subsequent field work, and communicate significant findings directly to the emergency responders and to the public through press conferences. As the immediate response effort winds down, the Clearinghouse will ensure that collected data are archived and made available through "lessons learned" reports and publications that follow significant earthquakes. Participants in the quarterly meetings of the Clearinghouse include representatives from state and federal agencies, universities, NGOs and other private groups. Overall management of the Clearinghouse is delegated to the agencies represented by the authors above.

  17. 77 FR 7536 - Revisions to the California State Implementation Plan, Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-13

    ... the California State Implementation Plan, Joaquin Valley Unified Air Pollution Control District AGENCY... the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portions of the California... U.S.C. 804(2). List of Subjects in 40 CFR Part 52 Environmental protection, Air pollution control...

  18. The Salton Seismic Imaging Project: Tomographic characterization of a sediment-filled rift valley and adjacent ranges, southern California

    NASA Astrophysics Data System (ADS)

    Davenport, K.; Hole, J. A.; Stock, J. M.; Fuis, G. S.; Carrick, E.; Tikoff, B.

    2011-12-01

    The Salton Trough in Southern California represents the northernmost rift of the Gulf of California extensional system. Relative motion between the Pacific and North American plates is accommodated by continental rifting in step-over zones between the San Andreas, Imperial, and Cerro Prieto transform faults. Rapid sedimentation from the Colorado River has isolated the trough from the southern portion of the Gulf of California, progressively filling the subsiding rift basin. Based on data from previous seismic surveys, the pre-existing continent has ruptured completely, and a new ~22 km thick crust has been created entirely by sedimentation overlying rift-related magmatism. The MARGINS, EarthScope, and USGS-funded Salton Seismic Imaging Project (SSIP) was designed to investigate the nature of this new crust, the ongoing process of continental rifting, and associated earthquake hazards. SSIP, acquired in March 2011, comprises 7 lines of onshore seismic refraction / wide-angle reflection data, 2 lines of refraction / reflection data in the Salton Sea, and a line of broadband stations. This presentation focuses on the refraction / wide-angle reflection line across the Imperial Valley, extending ~220 km across California from Otay Mesa, near Tijuana, to the Colorado River. The data from this line includes seventeen 100-160 kg explosive shots and receivers at 100 m spacing across the Imperial Valley to constrain the structure of the Salton Trough rift basin, including the Imperial Fault. Eight larger shots (600-920 kg) at 20-35 km spacing and receivers at 200-500 m spacing extend the line across the Peninsular Ranges and the Chocolate Mountains. These data will contrast the structure of the rift to that of the surrounding crust and provide constraints on whole-crust and uppermost mantle structure. Preliminary work has included tomographic inversion of first-arrival travel times across the Valley, emphasizing a minimum-structure approach to create a velocity model of the

  19. Reexamination of the subsurface fault structure in the vicinity of the 1989 moment-magnitude-6.9 Loma Prieta earthquake, central California, using steep-reflection, earthquake, and magnetic data

    USGS Publications Warehouse

    Zhang, Edward; Fuis, Gary S.; Catchings, Rufus D.; Scheirer, Daniel S.; Goldman, Mark; Bauer, Klaus

    2018-06-13

    We reexamine the geometry of the causative fault structure of the 1989 moment-magnitude-6.9 Loma Prieta earthquake in central California, using seismic-reflection, earthquake-hypocenter, and magnetic data. Our study is prompted by recent interpretations of a two-part dip of the San Andreas Fault (SAF) accompanied by a flower-like structure in the Coachella Valley, in southern California. Initially, the prevailing interpretation of fault geometry in the vicinity of the Loma Prieta earthquake was that the mainshock did not rupture the SAF, but rather a secondary fault within the SAF system, because network locations of aftershocks defined neither a vertical plane nor a fault plane that projected to the surface trace of the SAF. Subsequent waveform cross-correlation and double-difference relocations of Loma Prieta aftershocks appear to have clarified the fault geometry somewhat, with steeply dipping faults in the upper crust possibly connecting to the more moderately southwest-dipping mainshock rupture in the middle crust. Examination of steep-reflection data, extracted from a 1991 seismic-refraction profile through the Loma Prieta area, reveals three robust fault-like features that agree approximately in geometry with the clusters of upper-crustal relocated aftershocks. The subsurface geometry of the San Andreas, Sargent, and Berrocal Faults can be mapped using these features and the aftershock clusters. The San Andreas and Sargent Faults appear to dip northeastward in the uppermost crust and change dip continuously toward the southwest with depth. Previous models of gravity and magnetic data on profiles through the aftershock region also define a steeply dipping SAF, with an initial northeastward dip in the uppermost crust that changes with depth. At a depth 6 to 9 km, upper-crustal faults appear to project into the moderately southwest-dipping, planar mainshock rupture. The change to a planar dipping rupture at 6–9 km is similar to fault geometry seen in the

  20. Groundwater quality in the Indian Wells Valley, California

    USGS Publications Warehouse

    Dawson, Barbara J. Milby; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Indian Wells Valley is one of the study areas being evaluated. The Indian Wells study area is approximately 600 square miles (1,554 square kilometers) and includes the Indian Wells Valley groundwater basin (California Department of Water Resources, 2003). Indian Wells Valley has an arid climate and is part of the Mojave Desert. Average annual rainfall is about 6 inches (15 centimeters). The study area has internal drainage, with runoff from the surrounding mountains draining towards dry lake beds in the lower parts of the valley. Land use in the study area is approximately 97.0 percent (%) natural, 0.4% agricultural, and 2.6% urban. The primary natural land cover is shrubland. The largest urban area is the city of Ridgecrest (2010 population of 28,000). Groundwater in this basin is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from the Sierra Nevada to the west and from the other surrounding mountains. Recharge to the groundwater system is primarily runoff from the Sierra Nevada and to the west and from the other surrounding mountains. Recharge to the groundwater system is primarily runoff from the Sierra Nevada and direct infiltration from irrigation and septic systems. The primary sources of discharge are pumping wells and evapotranspiration near the dry lakebeds. The primary aquifers in the Indian Wells study area are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells in

  1. 3-D Velocity Model of the Coachella Valley, Southern California Based on Explosive Shots from the Salton Seismic Imaging Project

    NASA Astrophysics Data System (ADS)

    Persaud, P.; Stock, J. M.; Fuis, G. S.; Hole, J. A.; Goldman, M.; Scheirer, D. S.

    2014-12-01

    We have analyzed explosive shot data from the 2011 Salton Seismic Imaging Project (SSIP) across a 2-D seismic array and 5 profiles in the Coachella Valley to produce a 3-D P-wave velocity model that will be used in calculations of strong ground shaking. Accurate maps of seismicity and active faults rely both on detailed geological field mapping and a suitable velocity model to accurately locate earthquakes. Adjoint tomography of an older version of the SCEC 3-D velocity model shows that crustal heterogeneities strongly influence seismic wave propagation from moderate earthquakes (Tape et al., 2010). These authors improve the crustal model and subsequently simulate the details of ground motion at periods of 2 s and longer for hundreds of ray paths. Even with improvements such as the above, the current SCEC velocity model for the Salton Trough does not provide a match of the timing or waveforms of the horizontal S-wave motions, which Wei et al. (2013) interpret as caused by inaccuracies in the shallow velocity structure. They effectively demonstrate that the inclusion of shallow basin structure improves the fit in both travel times and waveforms. Our velocity model benefits from the inclusion of known location and times of a subset of 126 shots detonated over a 3-week period during the SSIP. This results in an improved velocity model particularly in the shallow crust. In addition, one of the main challenges in developing 3-D velocity models is an uneven stations-source distribution. To better overcome this challenge, we also include the first arrival times of the SSIP shots at the more widely spaced Southern California Seismic Network (SCSN) in our inversion, since the layout of the SSIP is complementary to the SCSN. References: Tape, C., et al., 2010, Seismic tomography of the Southern California crust based on spectral-element and adjoint methods: Geophysical Journal International, v. 180, no. 1, p. 433-462. Wei, S., et al., 2013, Complementary slip distributions

  2. Earthquake processes in the Rainbow Mountain-Fairview Peak-Dixie Valley, Nevada, region 1954-1959

    NASA Astrophysics Data System (ADS)

    Doser, Diane I.

    1986-11-01

    The 1954 Rainbow Mountain-Fairview Peak-Dixie Valley, Nevada, sequence produced the most extensive pattern of surface faults in the intermountain region in historic time. Five earthquakes of M>6.0 occurred during the first 6 months of the sequence, including the December 16, 1954, Fairview Peak (M = 7.1) and Dixie Valley (M = 6.8) earthquakes. Three 5.5≤M≤6.5 earthquakes occurred in the region in 1959, but none exhibited surface faulting. The results of the modeling suggest that the M>6.5 earthquakes of this sequence are complex events best fit by multiple source-time functions. Although the observed surface displacements for the July and August 1954 events showed only dip-slip motion, the fault plane solutions and waveform modeling suggest the earthquakes had significant components of right-lateral strike-slip motion (rakes of -135° to -145°). All of the earthquakes occurred along high-angle faults with dips of 40° to 70°. Seismic moments for individual subevents of the sequence range from 8.0 × 1017 to 2.5 × 1019 N m. Stress drops for the subevents, including the Fairview Peak subevents, were between 0.7 and 6.0 MPa.

  3. The Imperial Valley of California is critical to wintering Mountain Plovers

    USGS Publications Warehouse

    Wunder, Michael B.; Knopf, F.L.

    2003-01-01

    We surveyed Mountain Plovers (Charadrius montanus) wintering in the Imperial Valley of California in January 2001, and also recorded the types of crop fields used by plovers in this agricultural landscape. We tallied 4037 plovers in 36 flocks ranging in size from 4 to 596 birds. Plovers were more common on alfalfa and Bermudagrass fields than other field types. Further, most birds were on alfalfa fields that were currently being (or had recently been) grazed, primarily by domestic sheep. Plovers used Bermudagrass fields only after harvest and subsequent burning. Examination of Christmas Bird Count data from 1950–2000 indicated that the Mountain Plover has abandoned its historical wintering areas on the coastal plains of California. Numbers in the Central Valley seem to have undergone recent declines also. We believe that the cultivated landscape of the Imperial Valley provides wintering habitats for about half of the global population of Mountain Plovers. We attribute the current importance of the Imperial Valley for Mountain Plovers to loss of native coastal and Central Valley habitats rather than to a behavioral switching of wintering areas through time. Future changes in specific cropping or management practices in the Imperial Valley will have a major impact on the conservation status of this species.

  4. 75 FR 10690 - Revisions to the California State Implementation Plan, San Joaquin Valley Air Pollution Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-09

    ... the California State Implementation Plan, San Joaquin Valley Air Pollution Control District AGENCY... the San Joaquin Valley Air Pollution Control District (SJVAPCD) portion of the California State...)(2)). List of Subjects in 40 CFR Part 52 Environmental protection, Air pollution control...

  5. Color Image of Death Valley, California from SIR-C

    NASA Image and Video Library

    1999-09-27

    This radar image shows the area of Death Valley, California and the different surface types in the area. Radar is sensitive to surface roughness with rough areas showing up brighter than smooth areas, which appear dark.

  6. Earthquake Hazard Class Mapping by Parcel in Las Vegas Valley

    NASA Astrophysics Data System (ADS)

    Pancha, A.; Pullammanappallil, S.; Louie, J. N.; Hellmer, W. K.

    2011-12-01

    Clark County, Nevada completed the very first effort in the United States to map earthquake hazard class systematically through an entire urban area. The map is used in development and disaster response planning, in addition to its direct use for building code implementation and enforcement. The County contracted with the Nevada System of Higher Education to classify about 500 square miles including urban Las Vegas Valley, and exurban areas considered for future development. The Parcel Map includes over 10,000 surface-wave array measurements accomplished over three years using Optim's SeisOpt° ReMi measurement and processing techniques adapted for large scale data. These array measurements classify individual parcels on the NEHRP hazard scale. Parallel "blind" tests were conducted at 93 randomly selected sites. The rms difference between the Vs30 values yielded by the blind data and analyses and the Parcel Map analyses is 4.92%. Only six of the blind-test sites showed a difference with a magnitude greater than 10%. We describe a "C+" Class for sites with Class B average velocities but soft surface soil. The measured Parcel Map shows a clearly definable C+ to C boundary on the west side of the Valley. The C to D boundary is much more complex. Using the parcel map in computing shaking in the Valley for scenario earthquakes is crucial for obtaining realistic predictions of ground motions.

  7. Earthquake Education and Public Information Centers: A Collaboration Between the Earthquake Country Alliance and Free-Choice Learning Institutions in California

    NASA Astrophysics Data System (ADS)

    Degroot, R. M.; Springer, K.; Brooks, C. J.; Schuman, L.; Dalton, D.; Benthien, M. L.

    2009-12-01

    In 1999 the Southern California Earthquake Center initiated an effort to expand its reach to multiple target audiences through the development of an interpretive trail on the San Andreas fault at Wallace Creek and an earthquake exhibit at Fingerprints Youth Museum in Hemet. These projects and involvement with the San Bernardino County Museum in Redlands beginning in 2007 led to the creation of Earthquake Education and Public Information Centers (EPIcenters) in 2008. The impetus for the development of the network was to broaden participation in The Great Southern California ShakeOut. In 2009 it has grown to be more comprehensive in its scope including its evolution into a statewide network. EPIcenters constitute a variety of free-choice learning institutions, representing museums, science centers, libraries, universities, parks, and other places visited by a variety of audiences including families, seniors, and school groups. They share a commitment to demonstrating and encouraging earthquake preparedness. EPIcenters coordinate Earthquake Country Alliance activities in their county or region, lead presentations or organize events in their communities, or in other ways demonstrate leadership in earthquake education and risk reduction. The San Bernardino County Museum (Southern California) and The Tech Museum of Innovation (Northern California) serve as EPIcenter regional coordinating institutions. They interact with over thirty institutional partners who have implemented a variety of activities from displays and talks to earthquake exhibitions. While many activities are focused on the time leading up to and just after the ShakeOut, most EPIcenter members conduct activities year round. Network members at Kidspace Museum in Pasadena and San Diego Natural History Museum have formed EPIcenter focus groups on early childhood education and safety and security. This presentation highlights the development of the EPIcenter network, synergistic activities resulting from this

  8. ANALYSIS OF LOTIC MACROINVERTEBRATE ASSEMBLAGES IN CALIFORNIA'S CENTRAL VALLEY

    EPA Science Inventory

    Using multivariate and cluster analyses, we examined the relaitonships between chemical and physical characteristics and macroinvertebrate assemblages at sites sampled by R-EMAP in California's Central Valley. By contrasting results where community structure was summarized as met...

  9. Food and Environment. A Teachers' Resource Guide to California Valley Agriculture.

    ERIC Educational Resources Information Center

    Railton, Esther, Comp.

    Presented is a compilation of teaching resources prepared by teachers enrolled in a graduate-level environmental education course at California State University, Hayward. The emphasis of these materials is upon agriculture and related environmental practices in California's San Joaquin Valley. Following a description of course logistics are six…

  10. Simulated ground motion in Santa Clara Valley, California, and vicinity from M≥6.7 scenario earthquakes

    USGS Publications Warehouse

    Harmsen, Stephen C.; Hartzell, Stephen

    2008-01-01

    Models of the Santa Clara Valley (SCV) 3D velocity structure and 3D finite-difference software are used to predict ground motions from scenario earthquakes on the San Andreas (SAF), Monte Vista/Shannon, South Hayward, and Calaveras faults. Twenty different scenario ruptures are considered that explore different source models with alternative hypocenters, fault dimensions, and rupture velocities and three different velocity models. Ground motion from the full wave field up to 1 Hz is exhibited as maps of peak horizontal velocity and pseudospectral acceleration at periods of 1, 3, and 5 sec. Basin edge effects and amplification in sedimentary basins of the SCV are observed that exhibit effects from shallow sediments with relatively low shear-wave velocity (330 m/sec). Scenario earthquakes have been simulated for events with the following magnitudes: (1) M 6.8–7.4 Calaveras sources, (2) M 6.7–6.9 South Hayward sources, (3) M 6.7 Monte Vista/Shannon sources, and (4) M 7.1–7.2 Peninsula segment of the SAF sources. Ground motions are strongly influenced by source parameters such as rupture velocity, rise time, maximum depth of rupture, hypocenter, and source directivity. Cenozoic basins also exert a strong influence on ground motion. For example, the Evergreen Basin on the northeastern side of the SCV is especially responsive to 3–5-sec energy from most scenario earthquakes. The Cupertino Basin on the southwestern edge of the SCV tends to be highly excited by many Peninsula and Monte Vista fault scenarios. Sites over the interior of the Evergreen Basin can have long-duration coda that reflect the trapping of seismic energy within this basin. Plausible scenarios produce predominantly 5-sec wave trains with greater than 30 cm/sec sustained ground-motion amplitude with greater than 30 sec duration within the Evergreen Basin.

  11. Victor Valley College Agreement between the Victor Valley Community College District and the Victor Valley College California Teachers Association Chapter 1170. July 1989 - June 1992.

    ERIC Educational Resources Information Center

    Victor Valley Community Coll. District, Victorville, CA.

    The collective bargaining agreement between the Victor Valley College Board of Trustees and the Victor Valley College California Teachers Association/National Education Association is presented. This contract, covering the period from July 1989 through June 1992, deals with the following topics: bargaining agent recognition; district and…

  12. 77 FR 214 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-04

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... approval of revisions to the San Joaquin Valley Air Pollution Control District (SJVUAPCD) portion of the... used by the California Air Resources Board and air districts for evaluating air pollution control...

  13. 77 FR 58312 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-20

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control... section 307(b)(2)). List of Subjects in 40 CFR Part 52 Environmental protection, Air pollution control...

  14. FORESHOCKS AND TIME-DEPENDENT EARTHQUAKE HAZARD ASSESSMENT IN SOUTHERN CALIFORNIA.

    USGS Publications Warehouse

    Jones, Lucile M.

    1985-01-01

    The probability that an earthquake in southern California (M greater than equivalent to 3. 0) will be followed by an earthquake of larger magnitude within 5 days and 10 km (i. e. , will be a foreshock) is 6 plus or minus 0. 5 per cent (1 S. D. ), and is not significantly dependent on the magnitude of the possible foreshock between M equals 3 and M equals 5. The probability that an earthquake will be followed by an M greater than equivalent to 5. 0 main shock, however, increases with magnitude of the foreshock from less than 1 per cent at M greater than equivalent to 3 to 6. 5 plus or minus 2. 5 per cent (1 S. D. ) at M greater than equivalent to 5. The main shock will most likely occur in the first hour after the foreshock, and the probability that a main shock will occur in the first hour decreases with elapsed time from the occurrence of the possible foreshock by approximately the inverse of time. Thus, the occurrence of an earthquake of M greater than equivalent to 3. 0 in southern California increases the earthquake hazard within a small space-time window several orders of magnitude above the normal background level.

  15. Real-time forecasts of tomorrow's earthquakes in California: a new mapping tool

    USGS Publications Warehouse

    Gerstenberger, Matt; Wiemer, Stefan; Jones, Lucy

    2004-01-01

    We have derived a multi-model approach to calculate time-dependent earthquake hazard resulting from earthquake clustering. This file report explains the theoretical background behind the approach, the specific details that are used in applying the method to California, as well as the statistical testing to validate the technique. We have implemented our algorithm as a real-time tool that has been automatically generating short-term hazard maps for California since May of 2002, at http://step.wr.usgs.gov

  16. Fog and Haze in California's San Joaquin Valley

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This illustration features images of southern California and southwestern Nevada acquired on January 3, 2001 (Terra orbit 5569), and includes data from three of MISR's nine cameras. The San Joaquin Valley, which comprises the southern extent of California's Central Valley, covers much of the viewed area. Also visible are several of the Channel Islands near the bottom, and Mono and Walker Lakes, which stand out as darker patches near the top center, especially in the vertical and backward oblique images. Near the lower right of each image is the Los Angeles Basin, with the distinctive chevron shape of the Mojave Desert to its north.

    The Central Valley is a well-irrigated and richly productive agricultural area situated between the Coast Range and the snow-capped Sierra Nevadas. During the winter, the region is noted for its hazy overcasts and a low, thick ground fog known as the Tule. Owing to the effects of the atmosphere on reflected sunlight, dramatic differences in the MISR images are apparent as the angle of view changes. An area of thick, white fog in the San Joaquin Valley is visible in all three of the images. However, the pervasive haze that fills most of the valley is only slightly visible in the vertical view. At the oblique angles, the haze is highly distinguishable against the land surface background, particularly in the forward-viewing direction. Just above image center, the forward view also reveals bluish-tinged plumes near Lava Butte in Sequoia National Forest, where the National Interagency Coordination Center reported an active forest fire.

    The changing surface visibility in the multi-angle data allows us to derive the amount of atmospheric haze. In the lower right quadrant is a map of haze amount determined from automated processing of the MISR imagery. Low amounts of haze are shown in blue, and a variation in hue through shades of green, yellow, and red indicates progressively larger amounts of airborne particulates. Due to the

  17. Gravity survey and depth to bedrock in Carson Valley, Nevada-California

    USGS Publications Warehouse

    Maurer, D.K.

    1985-01-01

    Gravity data were obtained from 460 stations in Carson Valley, Nevada and California. The data have been interpreted to obtain a map of approximate depth to bedrock for use in a ground-water model of the valley. This map delineates the shape of the alluvium-filled basin and shows that the maximum depth to bedrock exceeds 5,000 feet, on the west side of the valley. A north-south trending offset in the bedrock surface shows that the Carson-Valley/Pine-Nut-Mountain block has not been tilted to the west as a simple unit, but is comprised of several smaller blocks. (USGS)

  18. Very-long-period volcanic earthquakes beneath Mammoth Mountain, California

    USGS Publications Warehouse

    Hill, D.P.; Dawson, P.; Johnston, M.J.S.; Pitt, A.M.; Biasi, G.; Smith, K.

    2002-01-01

    Detection of three very-long-period (VLP) volcanic earthquakes beneath Mammoth Mountain emphasizes that magmatic processes continue to be active beneath this young, eastern California volcano. These VLP earthquakes, which occured in October 1996 and July and August 2000, appear as bell-shaped pulses with durations of one to two minutes on a nearby borehole dilatometer and on the displacement seismogram from a nearby broadband seismometer. They are accompanied by rapid-fire sequences of high-frequency (HF) earthquakes and several long- period (LP) volcanic earthquakes. The limited VLP data are consistent with a CLVD source at a depth of ???3 km beneath the summit, which we interpret as resulting from a slug of fluid (CO2- saturated magmatic brine or perhaps basaltic magma) moving into a crack.

  19. Fault structure and kinematics of the Long Valley Caldera region, California, revealed by high-accuracy earthquake hypocenters and focal mechanism stress inversions

    NASA Astrophysics Data System (ADS)

    Prejean, Stephanie; Ellsworth, William; Zoback, Mark; Waldhauser, Felix

    2002-12-01

    We have determined high-resolution hypocenters for 45,000+ earthquakes that occurred between 1980 and 2000 in the Long Valley caldera area using a double-difference earthquake location algorithm and routinely determined arrival times. The locations reveal numerous discrete fault planes in the southern caldera and adjacent Sierra Nevada block (SNB). Intracaldera faults include a series of east/west-striking right-lateral strike-slip faults beneath the caldera's south moat and a series of more northerly striking strike-slip/normal faults beneath the caldera's resurgent dome. Seismicity in the SNB south of the caldera is confined to a crustal block bounded on the west by an east-dipping oblique normal fault and on the east by the Hilton Creek fault. Two NE-striking left-lateral strike-slip faults are responsible for most seismicity within this block. To understand better the stresses driving seismicity, we performed stress inversions using focal mechanisms with 50 or more first motions. This analysis reveals that the least principal stress direction systematically rotates across the studied region, from NE to SW in the caldera's south moat to WNW-ESE in Round Valley, 25 km to the SE. Because WNW-ESE extension is characteristic of the western boundary of the Basin and Range province, caldera area stresses appear to be locally perturbed. This stress perturbation does not seem to result from magma chamber inflation but may be related to the significant (˜20 km) left step in the locus of extension along the Sierra Nevada/Basin and Range province boundary. This implies that regional-scale tectonic processes are driving seismic deformation in the Long Valley caldera.

  20. Fault structure and kinematics of the Long Valley Caldera region, California, revealed by high-accuracy earthquake hypocenters and focal mechanism stress inversions

    USGS Publications Warehouse

    Prejean, Stephanie; Ellsworth, William L.; Zoback, Mark; Waldhauser, Felix

    2002-01-01

    We have determined high-resolution hypocenters for 45,000+ earthquakes that occurred between 1980 and 2000 in the Long Valley caldera area using a double-difference earthquake location algorithm and routinely determined arrival times. The locations reveal numerous discrete fault planes in the southern caldera and adjacent Sierra Nevada block (SNB). Intracaldera faults include a series of east/west-striking right-lateral strike-slip faults beneath the caldera's south moat and a series of more northerly striking strike-slip/normal faults beneath the caldera's resurgent dome. Seismicity in the SNB south of the caldera is confined to a crustal block bounded on the west by an east-dipping oblique normal fault and on the east by the Hilton Creek fault. Two NE-striking left-lateral strike-slip faults are responsible for most seismicity within this block. To understand better the stresses driving seismicity, we performed stress inversions using focal mechanisms with 50 or more first motions. This analysis reveals that the least principal stress direction systematically rotates across the studied region, from NE to SW in the caldera's south moat to WNW-ESE in Round Valley, 25 km to the SE. Because WNW-ESE extension is characteristic of the western boundary of the Basin and Range province, caldera area stresses appear to be locally perturbed. This stress perturbation does not seem to result from magma chamber inflation but may be related to the significant (???20 km) left step in the locus of extension along the Sierra Nevada/Basin and Range province boundary. This implies that regional-scale tectonic processes are driving seismic deformation in the Long Valley caldera.

  1. Steady, modest slip over multiple earthquake cycles on the Owens Valley and Little Lake fault zones

    NASA Astrophysics Data System (ADS)

    Amos, C. B.; Haddon, E. K.; Burgmann, R.; Zielke, O.; Jayko, A. S.

    2015-12-01

    A comprehensive picture of current plate-boundary deformation requires integration of short-term geodetic records with longer-term geologic strain. Comparing rates of deformation across these time intervals highlights potential time-dependencies in both geodetic and geologic records and yields critical insight into the earthquake deformation process. The southern Walker Lane Belt in eastern California represents one location where short-term strain recorded by geodesy apparently outpaces longer-term geologic fault slip measured from displaced rocks and landforms. This discrepancy persists both for individual structures and across the width of the deforming zone, where ~1 cm/yr of current dextral shear exceeds Quaternary slip rates summed across individual faults. The Owens Valley and Little Lake fault systems form the western boundary of the southern Walker Lane and host a range of published slip rate estimates from ~1 - 7 mm/yr over varying time intervals based on both geodetic and geologic measurements. New analysis of offset geomorphic piercing lines from airborne lidar and field measurements along the Owens Valley fault provides a snapshot of deformation during individual earthquakes and over many seismic cycles. Viewed in context of previously reported ages from pluvial and other landforms in Owens Valley, these offsets suggest slip rates of ~0.6 - 1.6 mm/yr over the past 103 - 105 years. Such rates agree with similar estimates immediately to the south on the Little Lake fault, where lidar measurements indicate dextral slip averaging ~0.6 - 1.3 mm/yr over comparable time intervals. Taken together, these results suggest steady, modest slip in the absence of significant variations over the Mid-to-Late Quaternary for a ~200 km span of the southwestern Walker Lane. Our findings argue against the presence of long-range fault interactions and slip-rate variations for this portion of the larger, regional fault network. This result also suggests that faster slip

  2. Earthquake and Tsunami planning, outreach and awareness in Humboldt County, California

    NASA Astrophysics Data System (ADS)

    Ozaki, V.; Nicolini, T.; Larkin, D.; Dengler, L.

    2008-12-01

    Humboldt County has the longest coastline in California and is one of the most seismically active areas of the state. It is at risk from earthquakes located on and offshore and from tsunamis generated locally from faults associated with the Cascadia subduction zone (CSZ), other regional fault systems, and from distant sources elsewhere in the Pacific. In 1995 the California Division of Mines and Geology published the first earthquake scenario to include both strong ground shaking effects and a tsunami. As a result of the scenario, the Redwood Coast Tsunami Work Group (RCTWG), an organization of representatives from government agencies, tribes, service groups, academia and the private sector from the three northern coastal California counties, was formed in 1996 to coordinate and promote earthquake and tsunami hazard awareness and mitigation. The RCTWG and its member agencies have sponsored a variety of projects including education/outreach products and programs, tsunami hazard mapping, signage and siren planning, and has sponsored an Earthquake - Tsunami Education Room at the Humboldt County fair for the past eleven years. Three editions of Living on Shaky Ground an earthquake-tsunami preparedness magazine for California's North Coast, have been published since 1993 and a fourth is due to be published in fall 2008. In 2007, Humboldt County was the first region in the country to participate in a tsunami training exercise at FEMA's Emergency Management Institute in Emmitsburg, MD and the first area in California to conduct a full-scale tsunami evacuation drill. The County has conducted numerous multi-agency, multi-discipline coordinated exercises using county-wide tsunami response plan. Two Humboldt County communities were recognized as TsunamiReady by the National Weather Service in 2007. Over 300 tsunami hazard zone signs have been posted in Humboldt County since March 2008. Six assessment surveys from 1993 to 2006 have tracked preparedness actions and personal

  3. The Northern California Earthquake Management System: A Unified System From Realtime Monitoring to Data Distribution

    NASA Astrophysics Data System (ADS)

    Neuhauser, D.; Dietz, L.; Lombard, P.; Klein, F.; Zuzlewski, S.; Kohler, W.; Hellweg, M.; Luetgert, J.; Oppenheimer, D.; Romanowicz, B.

    2006-12-01

    The longstanding cooperation between the USGS Menlo Park and UC Berkeley's Seismological Laboratory for monitoring earthquakes and providing data to the research community is achieving a new level of integration. While station support and data collection for each network (NC, BK, BP) remain the responsibilities of the host institution, picks, codas and amplitudes will be produced and shared between the data centers continuously. Thus, realtime earthquake processing from triggering and locating through magnitude and moment tensor calculation and Shakemap production will take place independently at both locations, improving the robustness of event reporting in the Northern California Earthquake Management Center. Parametric data will also be exchanged with the Southern California Earthquake Management System to allow statewide earthquake detection and processing for further redundancy within the California Integrated Seismic Network (CISN). The database plays an integral part in this system, providing the coordination for event processing as well as the repository for event, instrument (metadata) and waveform information. The same master database serves both realtime processing, data quality control and archival, and the data center which provides waveforms and earthquake data to users in the research community. Continuous waveforms from all BK, BP, and NC stations, event waveform gathers, and event information automatically become available at the Northern California Earthquake Data Center (NCEDC). Currently, the NCEDC is collecting and makes available over 4 TByes of data per year from the NCEMC stations and other seismic networks, as well as from GPS and and other geophysical instrumentation.

  4. 78 FR 59840 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-30

    ...] Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management District... of plan. * * * * * (c) * * * (428) * * * (i) * * * (B) Antelope Valley Air Quality Management...) * * * (i) * * * (B) Antelope Valley Air Quality Management District. (1) Rule 431.1, ``Sulfur Content of...

  5. School Safety Down to Earth: California's Earthquake-Resistant Schools.

    ERIC Educational Resources Information Center

    Progressive Architecture, 1979

    1979-01-01

    Schools in California being built to resist damage by earthquakes are part of a program to meet building standards established in 1933. The three new schools presented reflect the strengths and weaknesses of the program. (Author/MLF)

  6. Comparison of inversion models using AIRSAR data for Death Valley, California

    NASA Technical Reports Server (NTRS)

    Kierein-Young, Kathryn S.

    1993-01-01

    Polarimetric Airborne Synthetic Aperture Radar (AIRSAR) data were collected for the Geologic Remote Sensing Field Experiment (GRSFE) over Death Valley, California, USA, in September 1989. AIRSAR is a four-look, quid-polarizaiton, three frequency instrument. It collects measurements at C-band (5.66 cm), L-band (23.98 cm), and P-band (68.13 cm), and has a GIFOV of 10 meters and a swath width of 12 kilometers. Because the radar measures at three wavelengths, different scales of surface roughness are measured. Also, dielectric constants can be calculated from the data. The scene used in this study is in Death Valley, California and is located over Trail Canyon alluvial fan, the valley floor, and Artists Drive alluvial fan. The fans are very different in mineralogic makeup, size, and surface roughness. Trail Canyon fan is located on the west side of the valley at the base of the Panamint Range and is a large fan with older areas of desert pavement and younger active channels. The source for the material on southern part of the fan is mostly quartzites and there is an area of carbonate source on the northern part of the fan. Artists Drive fan is located at the base of the Black Mountains on the east side of the valley and is a smaller, young fan with its source mostly from volcanic rocks. The valley floor contains playa and salt deposits that range from smooth to Devil's Golf course type salt pinnacles.

  7. 76 FR 38572 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-01

    ... the California State Implementation Plan, Antelope Valley Air Quality Management District AGENCY... approve revisions to the Antelope Valley Air Quality Management District (AVAQMD) portion of the... approving with the dates that they were adopted by the Antelope Valley Air Quality Management District...

  8. Earthquake prediction research at the Seismological Laboratory, California Institute of Technology

    USGS Publications Warehouse

    Spall, H.

    1979-01-01

    Nevertheless, basic earthquake-related information has always been of consuming interest to the public and the media in this part of California (fig. 2.). So it is not surprising that earthquake prediction continues to be a significant reserach program at the laboratory. Several of the current spectrum of projects related to prediction are discussed below. 

  9. Color Image of Death Valley, California from SIR-C

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This radar image shows the area of Death Valley, California and the different surface types in the area. Radar is sensitive to surface roughness with rough areas showing up brighter than smooth areas, which appear dark. This is seen in the contrast between the bright mountains that surround the dark, smooth basins and valleys of Death Valley. The image shows Furnace Creek alluvial fan (green crescent feature) at the far right, and the sand dunes near Stove Pipe Wells at the center. Alluvial fans are gravel deposits that wash down from the mountains over time. Several other alluvial fans (semicircular features) can be seen along the mountain fronts in this image. The dark wrench-shaped feature between Furnace Creek fan and the dunes is a smooth flood-plain which encloses Cottonball Basin. Elevations in the valley range from 70 meters (230 feet) below sea level, the lowest in the United States, to more than 3,300 meters (10,800 feet) above sea level. Scientists are using these radar data to help answer a number of different questions about Earth's geology including how alluvial fans form and change through time in response to climatic changes and earthquakes. The image is centered at 36.629 degrees north latitude, 117.069 degrees west longitude. Colors in the image represent different radar channels as follows: red =L-band horizontally polarized transmitted, horizontally polarized received (LHH); green =L-band horizontally transmitted, vertically received (LHV) and blue = CHV.

    SIR-C/X-SAR is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground

  10. Post-Earthquake Traffic Capacity of Modern Bridges in California

    DOT National Transportation Integrated Search

    2010-03-01

    Evaluation of the capacity of a bridge to carry self-weight and traffic loads after an earthquake is essential for a : safe and timely re-opening of the bridge. In California, modern highway bridges designed using the Caltrans : Seismic Design Criter...

  11. Recent land-use/land-cover change in the Central California Valley

    USGS Publications Warehouse

    Soulard, Christopher E.; Wilson, Tamara S.

    2013-01-01

    Open access to Landsat satellite data has enabled annual analyses of modern land-use and land-cover change (LULCC) for the Central California Valley ecoregion between 2005 and 2010. Our annual LULCC estimates capture landscape-level responses to water policy changes, climate, and economic instability. From 2005 to 2010, agriculture in the region fluctuated along with regulatory-driven changes in water allocation as well as persistent drought conditions. Grasslands and shrublands declined, while developed lands increased in former agricultural and grassland/shrublands. Development rates stagnated in 2007, coinciding with the onset of the historic foreclosure crisis in California and the global economic downturn. We utilized annual LULCC estimates to generate interval-based LULCC estimates (2000–2005 and 2005–2010) and extend existing 27 year interval-based land change monitoring through 2010. Resulting change data provides insights into the drivers of landscape change in the Central California Valley ecoregion and represents the first, continuous, 37 year mapping effort of its kind.

  12. Preparing a population for an earthquake like Chi-Chi: The Great Southern California ShakeOut

    USGS Publications Warehouse

    Jones, Lucile M.; ,

    2009-01-01

    The Great Southern California ShakeOut was a week of special events featuring the largest earthquake drill in United States history. On November 13, 2008, over 5 million southern Californians pretended that a magnitude-7.8 earthquake had occurred and practiced actions that could reduce its impact on their lives. The primary message of the ShakeOut is that what we do now, before a big earthquake, will determine what our lives will be like after. The drill was based on a scenario of the impacts and consequences of such an earthquake on the Southern San Andreas Fault, developed by over 300 experts led by the U.S. Geological Survey in partnership with the California Geological Survey, the Southern California Earthquake Center, Earthquake Engineering Research Institute, lifeline operators, emergency services and many other organizations. The ShakeOut campaign was designed and implemented by earthquake scientists, emergency managers, sociologists, art designers and community participants. The means of communication were developed using results from sociological research on what encouraged people to take action. This was structured around four objectives: 1) consistent messages – people are more inclined to believe something when they hear the same thing from multiple sources; 2) visual reinforcement – people are more inclined to do something they see other people doing; 3) encourage “milling” or discussing contemplated action – people need to discuss an action with others they care about before committing to undertaking it; and 4) focus on concrete actions – people are more likely to prepare for a set of concrete consequences of a particular hazard than for an abstract concept of risk. The goals of the ShakeOut were established in Spring 2008 and were: 1) to register 5 million people to participate in the drill; 2) to change the culture of earthquake preparedness in southern California; and 3) to reduce earthquake losses in southern California. All of these

  13. Fluid-Faulting Interactions Examined Though Massive Waveform-Based Analyses of Earthquake Swarms in Volcanic and Tectonic Settings: Mammoth Mountain, Long Valley, Lassen, and Fillmore, California Swarms, 2014-2015

    NASA Astrophysics Data System (ADS)

    Shelly, D. R.; Ellsworth, W. L.; Prejean, S. G.; Hill, D. P.; Hardebeck, J.; Hsieh, P. A.

    2015-12-01

    Earthquake swarms, sequences of sustained seismicity, convey active subsurface processes that sometimes precede larger tectonic or volcanic episodes. Their extended activity and spatiotemporal migration can often be attributed to fluid pressure transients as migrating crustal fluids (typically water and CO2) interact with subsurface structures. Although the swarms analyzed here are interpreted to be natural in origin, the mechanisms of seismic activation likely mirror those observed for earthquakes induced by industrial fluid injection. Here, we use massive-scale waveform correlation to detect and precisely locate 3-10 times as many earthquakes as included in routine catalogs for recent (2014-2015) swarms beneath Mammoth Mountain, Long Valley Caldera, Lassen Volcanic Center, and Fillmore areas of California, USA. These enhanced catalogs, with location precision as good as a few meters, reveal signatures of fluid-faulting interactions, such as systematic migration, fault-valve behavior, and fracture mesh structures, not resolved in routine catalogs. We extend this analysis to characterize source mechanism similarity even for very small newly detected events using relative P and S polarity estimates. This information complements precise locations to define fault complexities that would otherwise be invisible. In particular, although swarms often consist of groups of highly similar events, some swarms contain a population of outliers with different slip and/or fault orientations. These events highlight the complexity of fluid-faulting interactions. Despite their different settings, the four swarms analyzed here share many similarities, including pronounced hypocenter migration suggestive of a fluid pressure trigger. This includes the July 2015 Fillmore swarm, which, unlike the others, occurred outside of an obvious volcanic zone. Nevertheless, it exhibited systematic westward and downdip migration on a ~1x1.5 km low-angle, NW-dipping reverse fault at midcrustal depth.

  14. Effects of Groundwater Development on Uranium: Central Valley, California, USA

    USGS Publications Warehouse

    Jurgens, Bryant C.; Fram, Miranda S.; Belitz, Kenneth; Burow, Karen R.; Landon, Matthew K.

    2009-01-01

    Uranium (U) concentrations in groundwater in several parts of the eastern San Joaquin Valley, California, have exceeded federal and state drinking water standards during the last 20 years. The San Joaquin Valley is located within the Central Valley of California and is one of the most productive agricultural areas in the world. Increased irrigation and pumping associated with agricultural and urban development during the last 100 years have changed the chemistry and magnitude of groundwater recharge, and increased the rate of downward groundwater movement. Strong correlations between U and bicarbonate suggest that U is leached from shallow sediments by high bicarbonate water, consistent with findings of previous work in Modesto, California. Summer irrigation of crops in agricultural areas and, to lesser extent, of landscape plants and grasses in urban areas, has increased Pco2 concentrations in the soil zone and caused higher temperature and salinity of groundwater recharge. Coupled with groundwater pumping, this process, as evidenced by increasing bicarbonate concentrations in groundwater over the last 100 years, has caused shallow, young groundwater with high U concentrations to migrate to deeper parts of the groundwater system that are tapped by public-supply wells. Continued downward migration of U-affected groundwater and expansion of urban centers into agricultural areas will likely be associated with increased U concentrations in public-supply wells. The results from this study illustrate the potential longterm effects of groundwater development and irrigation-supported agriculture on water quality in arid and semiarid regions around the world.

  15. Near-Surface Structure and Velocities of the Northeastern Santa Cruz Mountains and the Western Santa Clara Valley, California, From Seismic Imaging

    USGS Publications Warehouse

    Catchings, R.D.; Gandhok, G.; Goldman, M.R.; Steedman, Clare

    2007-01-01

    Introduction The Santa Clara Valley (SCV) is located in the southern San Francisco Bay area of California and is bounded by the Santa Cruz Mountains to the southwest, the Diablo Ranges to the northeast, and the San Francisco Bay to the north (Fig. 1). The SCV, which includes the City of San Jose, numerous smaller cities, and much of the high-technology manufacturing and research area commonly referred to as the Silicon Valley, has a population in excess of 1.7 million people (2000 U. S. Census;http://quickfacts.census.gov/qfd/states/06/06085.html The SCV is situated between major active faults of the San Andreas Fault system, including the San Andreas Fault to the southwest and the Hayward and Calaveras faults to the northeast, and other faults inferred to lie beneath the alluvium of the SCV (CWDR, 1967; Bortugno et al., 1991). The importance of the SCV as a major industrial center, its large population, and its proximity to major earthquake faults are important considerations with respect to earthquake hazards and water-resource management. The fault-bounded alluvial aquifer system beneath the valley is the source of about one-third of the water supply for the metropolitan area (Hanson et al., 2004). To better address the earthquake hazards of the SCV, the U.S. Geological Survey (USGS) has undertaken a program to evaluate potential seismic sources, the effects of strong ground shaking, and stratigraphy associated with the regional aquifer system. As part of that program and to better understand water resources of the valley, the USGS and the Santa Clara Valley Water District (SCVWD) began joint studies to characterize the faults, stratigraphy, and structures beneath the SCV in the year 2000. Such features are important to both agencies because they directly influence the availability and management of groundwater resources in the valley, and they affect the severity and distribution of strong shaking from local and regional earthquakes sources that may affect

  16. Post-earthquake traffic capacity of modern bridges in California.

    DOT National Transportation Integrated Search

    2010-03-01

    Evaluation of the capacity of a bridge to carry self-weight and traffic loads after an earthquake is essential for a safe and timely re-opening of the bridge. In California, modern highway bridges designed using the Caltrans Seismic Design Criteria a...

  17. Database of potential sources for earthquakes larger than magnitude 6 in Northern California

    USGS Publications Warehouse

    ,

    1996-01-01

    The Northern California Earthquake Potential (NCEP) working group, composed of many contributors and reviewers in industry, academia and government, has pooled its collective expertise and knowledge of regional tectonics to identify potential sources of large earthquakes in northern California. We have created a map and database of active faults, both surficial and buried, that forms the basis for the northern California portion of the national map of probabilistic seismic hazard. The database contains 62 potential sources, including fault segments and areally distributed zones. The working group has integrated constraints from broadly based plate tectonic and VLBI models with local geologic slip rates, geodetic strain rate, and microseismicity. Our earthquake source database derives from a scientific consensus that accounts for conflict in the diverse data. Our preliminary product, as described in this report brings to light many gaps in the data, including a need for better information on the proportion of deformation in fault systems that is aseismic.

  18. Space Radar Image of Death Valley, California

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This image shows Death Valley, California, centered at 36.629 degrees north latitude, 117.069 degrees west longitude. The image shows Furnace Creek alluvial fan and Furnace Creek Ranch at the far right, and the sand dunes near Stove Pipe Wells at the center. The dark fork-shaped feature between Furnace Creek fan and the dunes is a smooth flood-plain which encloses Cottonball Basin. This SIR-C/X-SAR supersite is an area of extensive field investigations and has been visited by both Space Radar Lab astronaut crews. Elevations in the valley range from 70 meters (230 feet) below sea level, the lowest in the United States, to more than 3,300 meters (10,800 feet) above sea level. Scientists are using SIR-C/X-SAR data from Death Valley to help answer a number of different questions about Earth's geology. One question concerns how alluvial fans are formed and change through time under the influence of climatic changes and earthquakes. Alluvial fans are gravel deposits that wash down from the mountains over time. They are visible in the image as circular, fan-shaped bright areas extending into the darker valley floor from the mountains. Information about the alluvial fans helps scientists study Earth's ancient climate. Scientists know the fans are built up through climatic and tectonic processes and they will use the SIR-C/X-SAR data to understand the nature and rates of weathering processes on the fans, soil formation and the transport of sand and dust by the wind. SIR-C/X-SAR's sensitivity to centimeter-scale (inch-scale) roughness provides detailed maps of surface texture. Such information can be used to study the occurrence and movement of dust storms and sand dunes. The goal of these studies is to gain a better understanding of the record of past climatic changes and the effects of those changes on a sensitive environment. This may lead to a better ability to predict future response of the land to different potential global climate-change scenarios. Death Valley is

  19. Images of crust beneath southern California will aid study of earthquakes and their effects

    USGS Publications Warehouse

    Fuis, G.S.; Okaya, D.A.; Clayton, R.W.; Lutter, W.J.; Ryberg, T.; Brocher, T.M.; Henyey, T.M.; Benthien, M.L.; Davis, P.M.; Mori, J.; Catchings, R.D.; ten Brink, Uri S.; Kohler, M.D.; Klitgord, Kim D.; Bohannon, R.G.

    1996-01-01

    The Whittier Narrows earthquake of 1987 and the Northridge earthquake of 1991 highlighted the earthquake hazards associated with buried faults in the Los Angeles region. A more thorough knowledge of the subsurface structure of southern California is needed to reveal these and other buried faults and to aid us in understanding how the earthquake-producing machinery works in this region.

  20. The earthquake prediction experiment at Parkfield, California

    USGS Publications Warehouse

    Roeloffs, E.; Langbein, J.

    1994-01-01

    Since 1985, a focused earthquake prediction experiment has been in progress along the San Andreas fault near the town of Parkfield in central California. Parkfield has experienced six moderate earthquakes since 1857 at average intervals of 22 years, the most recent a magnitude 6 event in 1966. The probability of another moderate earthquake soon appears high, but studies assigning it a 95% chance of occurring before 1993 now appear to have been oversimplified. The identification of a Parkfield fault "segment" was initially based on geometric features in the surface trace of the San Andreas fault, but more recent microearthquake studies have demonstrated that those features do not extend to seismogenic depths. On the other hand, geodetic measurements are consistent with the existence of a "locked" patch on the fault beneath Parkfield that has presently accumulated a slip deficit equal to the slip in the 1966 earthquake. A magnitude 4.7 earthquake in October 1992 brought the Parkfield experiment to its highest level of alert, with a 72-hour public warning that there was a 37% chance of a magnitude 6 event. However, this warning proved to be a false alarm. Most data collected at Parkfield indicate that strain is accumulating at a constant rate on this part of the San Andreas fault, but some interesting departures from this behavior have been recorded. Here we outline the scientific arguments bearing on when the next Parkfield earthquake is likely to occur and summarize geophysical observations to date.

  1. A coccidioidomycosis outbreak following the Northridge, Calif, earthquake

    USGS Publications Warehouse

    Schneider, E.; Hajjeh, R.A.; Spiegel, R.A.; Jibson, R.W.; Harp, E.L.; Marshall, G.A.; Gunn, R.A.; McNeil, M.M.; Pinner, R.W.; Baron, R.C.; Burger, R.C.; Hutwagner, L.C.; Crump, C.; Kaufman, L.; Reef, S.E.; Feldman, G.M.; Pappagianis, D.; Werner, S.B.

    1997-01-01

    Objective. - To describe a coccidioidomycosis outbreak in Ventura County following the January 1994 earthquake, centered in Northridge, Calif, and to identify factors that increased the risk for acquiring acute coccidioidomycosis infection. Design. - Epidemic investigation, population- based skin test survey, and case-control study. Setting. - Ventura County, California. Results. - In Ventura County, between January 24 and March 15, 1994, 203 outbreak-associated coccidioidomycosis cases, including 3 fatalities, were identified (attack rate [AR], 30 cases per 100 000 population). The majority of cases (56%) and the highest AR (114 per 100 000 population) occurred in the town of Simi Valley, a community located at the base of a mountain range that experienced numerous landslides associated with the earthquake. Disease onset for cases peaked 2 weeks after the earthquake. The AR was 2.8 times greater for persons 40 years of age and older than for younger persons (relative risk, 2.8; 95% confidence interval [CI], 2.1-3.7; P<.001). Environmental data indicated that large dust clouds, generated by landslides following the earthquake and strong aftershocks in the Santa Susana Mountains north of Simi Valley, were dispersed into nearby valleys by northeast winds. Simi Valley case-control study data indicated that physically being in a dust cloud (odds ratio, 3.0; 95% CI, 1.6-5.4; P<.001) and time spent in a dust cloud (P<.001) significantly increased the risk for being diagnosed with acute coccidioidomycosis. Conclusions. - Both the location and timing of cases strongly suggest that the coccidioidomycosis outbreak in Ventura County was caused when arthrospores were spread in dust clouds generated by the earthquake. This is the first report of a coccidioidomycosis outbreak following an earthquake. Public and physician awareness, especially in endemic areas following similar dust cloud- generating events, may result in prevention and early recognition of acute

  2. Increased body mass of ducks wintering in California's Central Valley

    USGS Publications Warehouse

    Fleskes, Joseph P.; Yee, Julie L.; Yarris, Gregory S.; Loughman, Daniel L.

    2016-01-01

    Waterfowl managers lack the information needed to fully evaluate the biological effects of their habitat conservation programs. We studied body condition of dabbling ducks shot by hunters at public hunting areas throughout the Central Valley of California during 2006–2008 compared with condition of ducks from 1979 to 1993. These time periods coincide with habitat increases due to Central Valley Joint Venture conservation programs and changing agricultural practices; we modeled to ascertain whether body condition differed among waterfowl during these periods. Three dataset comparisons indicate that dabbling duck body mass was greater in 2006–2008 than earlier years and the increase was greater in the Sacramento Valley and Suisun Marsh than in the San Joaquin Valley, differed among species (mallard [Anas platyrhynchos], northern pintail [Anas acuta], America wigeon [Anas americana], green-winged teal [Anas crecca], and northern shoveler [Anas clypeata]), and was greater in ducks harvested late in the season. Change in body mass also varied by age–sex cohort and month for all 5 species and by September–January rainfall for all except green-winged teal. The random effect of year nested in period, and sometimes interacting with other factors, improved models in many cases. Results indicate that improved habitat conditions in the Central Valley have resulted in increased winter body mass of dabbling ducks, especially those that feed primarily on seeds, and this increase was greater in regions where area of post-harvest flooding of rice and other crops, and wetland area, has increased. Conservation programs that continue to promote post-harvest flooding and other agricultural practices that benefit wintering waterfowl and continue to restore and conserve wetlands would likely help maintain body condition of wintering dabbling ducks in the Central Valley of California.

  3. 76 FR 41745 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-15

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... approval and limited disapproval of revisions to the San Joaquin Valley Unified Air Pollution Control... Valley Unified Air Pollution Control District (SJVUAPCD) Rule 4682, Polystyrene, Polyethylene, and...

  4. 76 FR 68103 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-03

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of the... State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District Rule 4692...

  5. Deformation from the 1989 Loma Prieta earthquake near the southwest margin of the Santa Clara Valley, California

    USGS Publications Warehouse

    Schmidt, Kevin M.; Ellen, Stephen D.; Peterson, David M.

    2014-01-01

    To gain additional measurement of any permanent ground deformation that accompanied this damage, we compiled and conducted post-earthquake surveys along two 5-km lines of horizontal control and a 15-km level line. Measurements of horizontal distortion indicate approximately 0.1 m shortening in a NE-SW direction across the valley margin, similar to the amount measured in the channel lining. Evaluation of precise leveling by the National Geodetic Survey showed a downwarp, with an amplitude of >0.1 m over a span of >12 km, that resembled regional geodetic models of coseismic deformation. Although the leveling indicates broad, regional warping, abrupt discontinuities characteristic of faulting characterize both the broad-scale distribution of damage and the local deformation of the channel lining. Reverse movement largely along preexisting faults and probably enhanced significantly by warping combined with enhanced ground shaking, produced the documented coseismic ground deformation.

  6. Earthquake geology and paleoseismology of major strands of the San Andreas fault system: Chapter 38

    USGS Publications Warehouse

    Rockwell, Thomas; Scharer, Katherine M.; Dawson, Timothy E.

    2016-01-01

    The San Andreas fault system in California is one of the best-studied faults in the world, both in terms of the long-term geologic history and paleoseismic study of past surface ruptures. In this paper, we focus on the Quaternary to historic data that have been collected from the major strands of the San Andreas fault system, both on the San Andreas Fault itself, and the major subparallel strands that comprise the plate boundary, including the Calaveras-Hayward- Rogers Creek-Maacama fault zone and the Concord-Green Valley-Bartlett Springs fault zone in northern California, and the San Jacinto and Elsinore faults in southern California. The majority of the relative motion between the Pacific and North American lithospheric plates is accommodated by these faults, with the San Andreas slipping at about 34 mm/yr in central California, decreasing to about 20 mm/yr in northern California north of its juncture with the Calaveras and Concord faults. The Calaveras-Hayward-Rogers Creek-Maacama fault zone exhibits a slip rate of 10-15 mm/yr, whereas the rate along the Concord-Green Valley-Bartlett Springs fault zone is lower at about 5 mm/yr. In southern California, the San Andreas exhibits a slip rate of about 35 mm/yr along the Mojave section, decreasing to as low as 10-15 mm/yr along its juncture with the San Jacinto fault, and about 20 mm/yr in the Coachella Valley. The San Jacinto and Elsinore fault zones exhibit rates of about 15 and 5 mm/yr, respectively. The average recurrence interval for surface-rupturing earthquakes along individual elements of the San Andreas fault system range from 100-500 years and is consistent with slip rate at those sites: higher slip rates produce more frequent or larger earthquakes. There is also evidence of short-term variations in strain release (slip rate) along various fault sections, as expressed as “flurries” or clusters of earthquakes as well as periods of relatively fewer surface ruptures in these relatively short records. This

  7. Rare earth element content of thermal fluids from Surprise Valley, California

    DOE Data Explorer

    Andrew Fowler

    2015-09-23

    Rare earth element measurements for thermal fluids from Surprise Valley, California. Samples were collected in acid washed HDPE bottles and acidified with concentrated trace element clean (Fisher Scientific) nitric acid. Samples were pre-concentratated by a factor of approximately 10 using chelating resin with and IDA functional group and measured on magnetic sector ICP-MS. Samples include Seyferth Hot Springs, Surprise Valley Resort Mineral Well, Leonard's Hot Spring, and Lake City Mud Volcano Boiling Spring.

  8. Fault-zone guided waves from explosions in the San Andreas fault at Parkfield and Cienega Valley, California

    USGS Publications Warehouse

    Li, Y.-G.; Ellsworth, W.L.; Thurber, C.H.; Malin, P.E.; Aki, K.

    1997-01-01

    Fault-zone guided waves were successfully excited by near-surface explosions in the San Andreas fault zone both at Parkfield and Cienega Valley, central California. The guided waves were observed on linear, three-component seismic arrays deployed across the fault trace. These waves were not excited by explosions located outside the fault zone. The amplitude spectra of guided waves show a maximum peak at 2 Hz at Parkfield and 3 Hz at Cienega Valley. The guided wave amplitude decays sharply with observation distance from the fault trace. The explosion-excited fault-zone guided waves are similar to those generated by earthquakes at Parkfield but have lower frequencies and travel more slowly. These observations suggest that the fault-zone wave guide has lower seismic velocities as it approaches the surface at Parkfield. We have modeled the waveforms as S waves trapped in a low-velocity wave guide sandwiched between high-velocity wall rocks, resulting in Love-type fault-zone guided waves. While the results are nonunique, the Parkfield data are adequately fit by a shallow wave guide 170 m wide with an S velocity 0.85 km/sec and an apparent Q ??? 30 to 40. At Cienega Valley, the fault-zone wave guide appears to be about 120 m wide with an S velocity 0.7 km/sec and a Q ??? 30.

  9. Southern California Earthquake Center Geologic Vertical Motion Database

    NASA Astrophysics Data System (ADS)

    Niemi, Nathan A.; Oskin, Michael; Rockwell, Thomas K.

    2008-07-01

    The Southern California Earthquake Center Geologic Vertical Motion Database (VMDB) integrates disparate sources of geologic uplift and subsidence data at 104- to 106-year time scales into a single resource for investigations of crustal deformation in southern California. Over 1800 vertical deformation rate data points in southern California and northern Baja California populate the database. Four mature data sets are now represented: marine terraces, incised river terraces, thermochronologic ages, and stratigraphic surfaces. An innovative architecture and interface of the VMDB exposes distinct data sets and reference frames, permitting user exploration of this complex data set and allowing user control over the assumptions applied to convert geologic and geochronologic information into absolute uplift rates. Online exploration and download tools are available through all common web browsers, allowing the distribution of vertical motion results as HTML tables, tab-delimited GIS-compatible text files, or via a map interface through the Google Maps™ web service. The VMDB represents a mature product for research of fault activity and elastic deformation of southern California.

  10. Effects of Groundwater Development on Uranium: Central Valley, California, USA

    USGS Publications Warehouse

    Jurgens, B.C.; Fram, M.S.; Belitz, K.; Burow, K.R.; Landon, M.K.

    2010-01-01

    Uranium (U) concentrations in groundwater in several parts of the eastern San Joaquin Valley, California, have exceeded federal and state drinking water standards during the last 20 years. The San Joaquin Valley is located within the Central Valley of California and is one of the most productive agricultural areas in the world. Increased irrigation and pumping associated with agricultural and urban development during the last 100 years have changed the chemistry and magnitude of groundwater recharge, and increased the rate of downward groundwater movement. Strong correlations between U and bicarbonate suggest that U is leached from shallow sediments by high bicarbonate water, consistent with findings of previous work in Modesto, California. Summer irrigation of crops in agricultural areas and, to lesser extent, of landscape plants and grasses in urban areas, has increased Pco2 concentrations in the soil zone and caused higher temperature and salinity of groundwater recharge. Coupled with groundwater pumping, this process, as evidenced by increasing bicarbonate concentrations in groundwater over the last 100 years, has caused shallow, young groundwater with high U concentrations to migrate to deeper parts of the groundwater system that are tapped by public-supply wells. Continued downward migration of U-affected groundwater and expansion of urban centers into agricultural areas will likely be associated with increased U concentrations in public-supply wells. The results from this study illustrate the potential long-term effects of groundwater development and irrigation-supported agriculture on water quality in arid and semiarid regions around the world. Journal compilation ?? 2009 National Ground Water Association. No claim to original US government works.

  11. Preliminary hydrogeologic assessment near the boundary of the Antelope Valley and El Mirage Valley groundwater basins, California

    USGS Publications Warehouse

    Stamos, Christina L.; Christensen, Allen H.; Langenheim, Victoria

    2017-07-19

    The increasing demands on groundwater for water supply in desert areas in California and the western United States have resulted in the need to better understand groundwater sources, availability, and sustainability. This is true for a 650-square-mile area that encompasses the Antelope Valley, El Mirage Valley, and Upper Mojave River Valley groundwater basins, about 50 miles northeast of Los Angeles, California, in the western part of the Mojave Desert. These basins have been adjudicated to ensure that groundwater rights are allocated according to legal judgments. In an effort to assess if the boundary between the Antelope Valley and El Mirage Valley groundwater basins could be better defined, the U.S. Geological Survey began a cooperative study in 2014 with the Mojave Water Agency to better understand the hydrogeology in the area and investigate potential controls on groundwater flow and availability, including basement topography.Recharge is sporadic and primarily from small ephemeral washes and streams that originate in the San Gabriel Mountains to the south; estimates range from about 400 to 1,940 acre-feet per year. Lateral underflow from adjacent basins has been considered minor in previous studies; underflow from the Antelope Valley to the El Mirage Valley groundwater basin has been estimated to be between 100 and 1,900 acre-feet per year. Groundwater discharge is primarily from pumping, mostly by municipal supply wells. Between October 2013 and September 2014, the municipal pumpage in the Antelope Valley and El Mirage Valley groundwater basins was reported to be about 800 and 2,080 acre-feet, respectively.This study was motivated by the results from a previously completed regional gravity study, which suggested a northeast-trending subsurface basement ridge and saddle approximately 3.5 miles west of the boundary between the Antelope Valley and El Mirage Valley groundwater basins that might influence groundwater flow. To better define potential basement

  12. 75 FR 4759 - Withdrawal of Proposed Rule Revising the California State Implementation Plan, San Joaquin Valley...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-29

    ... Proposed Rule Revising the California State Implementation Plan, San Joaquin Valley Unified Air Pollution... approval of revisions to the San Joaquin Valley Unified Air Pollution Control District portion of the... revisions to the San Joaquin Valley Unified Air Pollution Control District (``District'') portion of the...

  13. 75 FR 3996 - Revisions to the California State Implementation Plan, San Joaquin Valley Air Pollution Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-26

    ... the California State Implementation Plan, San Joaquin Valley Air Pollution Control District AGENCY... limited disapproval of revisions to the San Joaquin Valley Air Pollution Control District (SJVAPCD or... Valley Air Pollution Control District; letter dated and received August 17, 2009. After the close of the...

  14. 75 FR 28509 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-21

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... approve revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of... Joaquin Valley Unified Air Pollution Control District, No. 08-17309 (9th Circuit)). In that case, NAHB...

  15. 78 FR 49925 - Revisions to California State Implementation Plan, Antelope Valley Air Quality Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-16

    ... California State Implementation Plan, Antelope Valley Air Quality Management District and Ventura County Air...: EPA is taking direct final action to approve revisions to the Antelope Valley Air Quality Air Management District (AVAQMD) and Ventura County Air Pollution Control District (VCAPCD) portions of the...

  16. Blue and Valley Oak Seedling Establishment on California's Hardwood Rangelands

    Treesearch

    Theodore E. Adams Jr.; Peter B. Sands; William H. Weitkamp; Neil K. McDougald

    1991-01-01

    Factors contributing to poor establishment of blue oak (Quercus douglasii) and valley oak (Q. lobata) in California oak-grassland savannas were studied in a series of acorn seeding experiments initiated in 1985. Exclusion of large herbivores permitted examination of herbaceous interference and small mammal and insect depredation....

  17. 1957 Gobi-Altay, Mongolia, earthquake as a prototype for southern California's most devastating earthquake

    USGS Publications Warehouse

    Bayarsayhan, C.; Bayasgalan, A.; Enhtuvshin, B.; Hudnut, K.W.; Kurushin, R.A.; Molnar, P.; Olziybat, M.

    1996-01-01

    The 1957 Gobi-Altay earthquake was associated with both strike-slip and thrust faulting, processes similar to those along the San Andreas fault and the faults bounding the San Gabriel Mountains just north of Los Angeles, California. Clearly, a major rupture either on the San Andreas fault north of Los Angeles or on the thrust faults bounding the Los Angeles basin poses a serious hazard to inhabitants of that area. By analogy with the Gobi-Altay earthquake, we suggest that simultaneous rupturing of both the San Andreas fault and the thrust faults nearer Los Angeles is a real possibility that amplifies the hazard posed by ruptures on either fault system separately.

  18. Groundwater quality in the Bear Valley and Lake Arrowhead Watershed, California

    USGS Publications Warehouse

    Mathany, Timothy; Burton, Carmen; Fram, Miranda S.

    2017-06-20

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. The Bear Valley and Lake Arrowhead Watershed study areas in southern California compose one of the study units being evaluated.

  19. Effects of the New Madrid earthquake series in the Mississippi Alluvial Valley. Final report

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Saucier, R.T.

    1977-02-01

    Geological effects of the New Madrid earthquake series of 1811-12 in the upper portion of the Lower Mississippi Valley include land subsidence, uplift or doming, landslides, bank caving, fissuring, and sand blow phenomena. Features resulting from the liquefaction of sand are widespread in the alluvial valley and offer the greatest potential for definitively assessing the effects of major earthquakes on thick alluvial deposits and predicting the recurrence interval of infrequent major earthquakes in the region. However, liquefaction phenomena have not been the subject of detailed geological investigations applying knowledge of alluvial morphology and earth sciences methodology. Comparative aerial photo interpretationmore » has been used to classify liquefaction phenomena according to morphology, distribution, and relationship to major depositional environments. Surface morphology and spatial distribution of sand blows and fissures indicate basic control by drainage lines, water table position, and thickness of fine-grained topstratum deposits, Research efforts have been aimed at locating field test sites where the subsurface expression of the liquefaction phenomena can be investigated through trenching and land planing. Subsurface expression is presumed to be more permanent than surface expression and may permit the recognition of such features in older formations. Evidence of fissures and related phenomena is being sought in older Quaternary deposits to permit estimates of the frequency of past major earthquakes.« less

  20. Determining earthquake recurrence intervals from deformational structures in young lacustrine sediments

    USGS Publications Warehouse

    Sims, John D.

    1975-01-01

    Examination of the silty sediments in the lower Van Normal reservoir after the 1971 San Fernando, California earthquake revealed three zones of deformational structures in the 1-m-thick sequence of sediments exposed over about 2 km2 of the reservoir bottom. These zones are correlated with moderate earthquakes that shook the San Fernando area in 1930, 1952, and 1971. The success of this study, coupled with the experimental formation of deformational structures similar to those of the Van Norman reservoir, led to a search for similar structures in Pleistocene and Holocene lakes and lake sediments in other seismically active areas. Thus, studies have been started in Pleistocene and Holocene silty and sandy lake sediments in the Imperial Valley, southeastern California; Clear Lake, in northern California; and the Puget Sound area of Washington. The Imperial Valley study has yielded spectacular results: five zones of structures in the upper 10 m of Late Holocene sediments near Brawley have been correlated over an area of approximately 100 km2, using natural outcrops. These structures are similar to those of the Van Norman reservoir and are interpreted to represent at least five moderate to large earthquakes that affected the southern Imperial Valley area during Late Holocene time. The Clear Lake study has provided ambiguous results with respect to determination of earthquake recurrence intervals because the cores studied are in clayey rich in organic material sediments that have low liquefaction potential. A study of Late Pleistocene varved glacio-lacustrine sediments has been started in the Puget Sound area of Washington, and thirteen sites have been examined. One has yielded 18.75 m of sediments that contains 1,804 varves and fourteen deformed zones interpreted as being caused by earthquake, because they are identical to structures formed experimentally by simulated seismic shaking. Correlation of deformational structures with seismic events is based on:(1) proximity

  1. Hydrologic and geochemical monitoring in Long Valley Caldera, Mono County, California, 1982-1984

    USGS Publications Warehouse

    Farrar, C.D.; Sorey, M.L.; Rojstaczer, S.; Janik, C.J.; Mariner, R.H.; Winnett, T.L.; Clark, M.D.

    1985-01-01

    The Long Valley caldera is a potentially active volcanic area on the eastern side of the Sierra Nevada in east-central California. Hydrologic and geochemical monitoring of surface and subsurface features began in July 1982 to determine if changes were occurring in response to processes causing earthquakes and crustal deformation. Differences since 1982 in fluid chemistry of springs has been minor except at Casa Diablo, where rapid fluctuations in chemistry result from near surface boiling and mixing. Ratios of 3-He/4-He and 13-C/12-C in hot springs and fumaroles are consistent with a magnetic source for some of the carbon and helium discharged in thermal areas, and observed changes in 3-He/4-He between 1978 and 1984 suggest changes in the magmatic component. Significant fluctuations in hot spring discharge recorded at several sites since 1982 closely followed earthquake activity. Water levels in wells have been used as strain meters to detect rock deformation associated with magmatic and tectonic activity and to construct a water table contour map. Coseismic water level fluctuations of as much as 0.6 ft have been observed but no clear evidence of deformation caused by magmatic intrusions can be seen in the well records through 1984. Temperature profiles in wells, which can be used to delineate regionally continuous zones of lateral flow of hot water across parts of the caldera, have remained constant at all but two sites. (Author 's abstract)

  2. 77 FR 2469 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-18

    ... the California State Implementation Plan, Antelope Valley Air Quality Management District and Imperial... Quality Management District (AVAQMD) and Imperial County Air Pollution Control District (ICAPCD) portions... Technology (RACT),'' adopted on February 23, 2010. * * * * * (G) Antelope Valley Air Quality Management...

  3. San Andreas fault geometry at Desert Hot Springs, California, and its effects on earthquake hazards and groundwater

    USGS Publications Warehouse

    Catchings, R.D.; Rymer, M.J.; Goldman, M.R.; Gandhok, G.

    2009-01-01

    The Mission Creek and Banning faults are two of the principal strands of the San Andreas fault zone in the northern Coachella Valley of southern California. Structural characteristics of the faults affect both regional earthquake hazards and local groundwater resources. We use seismic, gravity, and geological data to characterize the San Andreas fault zone in the vicinity of Desert Hot Springs. Seismic images of the upper 500 m of the Mission Creek fault at Desert Hot Springs show multiple fault strands distributed over a 500 m wide zone, with concentrated faulting within a central 200 m wide area of the fault zone. High-velocity (up to 5000 m=sec) rocks on the northeast side of the fault are juxtaposed against a low-velocity (6.0) earthquakes in the area (in 1948 and 1986) occurred at or near the depths (~10 to 12 km) of the merged (San Andreas) fault. Large-magnitude earthquakes that nucleate at or below the merged fault will likely generate strong shaking from guided waves along both fault zones and from amplified seismic waves in the low-velocity basin between the two fault zones. The Mission Creek fault zone is a groundwater barrier with the top of the water table varying by 60 m in depth and the aquifer varying by about 50 m in thickness across a 200 m wide zone of concentrated faulting.

  4. Earthquake Rate Model 2 of the 2007 Working Group for California Earthquake Probabilities, Magnitude-Area Relationships

    USGS Publications Warehouse

    Stein, Ross S.

    2008-01-01

    The Working Group for California Earthquake Probabilities must transform fault lengths and their slip rates into earthquake moment-magnitudes. First, the down-dip coseismic fault dimension, W, must be inferred. We have chosen the Nazareth and Hauksson (2004) method, which uses the depth above which 99% of the background seismicity occurs to assign W. The product of the observed or inferred fault length, L, with the down-dip dimension, W, gives the fault area, A. We must then use a scaling relation to relate A to moment-magnitude, Mw. We assigned equal weight to the Ellsworth B (Working Group on California Earthquake Probabilities, 2003) and Hanks and Bakun (2007) equations. The former uses a single logarithmic relation fitted to the M=6.5 portion of data of Wells and Coppersmith (1994); the latter uses a bilinear relation with a slope change at M=6.65 (A=537 km2) and also was tested against a greatly expanded dataset for large continental transform earthquakes. We also present an alternative power law relation, which fits the newly expanded Hanks and Bakun (2007) data best, and captures the change in slope that Hanks and Bakun attribute to a transition from area- to length-scaling of earthquake slip. We have not opted to use the alternative relation for the current model. The selections and weights were developed by unanimous consensus of the Executive Committee of the Working Group, following an open meeting of scientists, a solicitation of outside opinions from additional scientists, and presentation of our approach to the Scientific Review Panel. The magnitude-area relations and their assigned weights are unchanged from that used in Working Group (2003).

  5. Rates and patterns of surface deformation from laser scanning following the South Napa earthquake, California

    USGS Publications Warehouse

    DeLong, Stephen B.; Lienkaemper, James J.; Pickering, Alexandra J; Avdievitch, Nikita N.

    2015-01-01

    The A.D. 2014 M6.0 South Napa earthquake, despite its moderate magnitude, caused significant damage to the Napa Valley in northern California (USA). Surface rupture occurred along several mapped and unmapped faults. Field observations following the earthquake indicated that the magnitude of postseismic surface slip was likely to approach or exceed the maximum coseismic surface slip and as such presented ongoing hazard to infrastructure. Using a laser scanner, we monitored postseismic deformation in three dimensions through time along 0.5 km of the main surface rupture. A key component of this study is the demonstration of proper alignment of repeat surveys using point cloud–based methods that minimize error imposed by both local survey errors and global navigation satellite system georeferencing errors. Using solid modeling of natural and cultural features, we quantify dextral postseismic displacement at several hundred points near the main fault trace. We also quantify total dextral displacement of initially straight cultural features. Total dextral displacement from both coseismic displacement and the first 2.5 d of postseismic displacement ranges from 0.22 to 0.29 m. This range increased to 0.33–0.42 m at 59 d post-earthquake. Furthermore, we estimate up to 0.15 m of vertical deformation during the first 2.5 d post-earthquake, which then increased by ∼0.02 m at 59 d post-earthquake. This vertical deformation is not expressed as a distinct step or scarp at the fault trace but rather as a broad up-to-the-west zone of increasing elevation change spanning the fault trace over several tens of meters, challenging common notions about fault scarp development in strike-slip systems. Integrating these analyses provides three-dimensional mapping of surface deformation and identifies spatial variability in slip along the main fault trace that we attribute to distributed slip via subtle block rotation. These results indicate the benefits of laser scanner surveys along

  6. 77 FR 12526 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-01

    ... the California State Implementation Plan, Antelope Valley Air Quality Management District and Mojave Desert Quality Management District AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule. SUMMARY: EPA is proposing to approve revisions to the Antelope Valley Air Quality Management District...

  7. 78 FR 25011 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-29

    ... the California State Implementation Plan, Antelope Valley Air Quality Management District, Santa Barbara County Air Pollution Control District, South Coast Air Quality Management District and Ventura... rule. SUMMARY: EPA is proposing to approve revisions to the Antelope Valley Air Quality Management...

  8. 78 FR 58459 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-24

    ... the California State Implementation Plan, Antelope Valley Air Quality Management District, Santa Barbara County Air Pollution Control District, South Coast Air Quality Management District and Ventura.... SUMMARY: EPA is finalizing approval of revisions to the Antelope Valley Air Quality Management District...

  9. Thin-skinned tectonics of the Upper Ojai Valley and Sulphur Mountain area, Ventura basin, California

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Huftile, G.J.

    1991-08-01

    By integrating surface mapping with subsurface well data and drawing cross sections and subsurface maps, the geometry of shallow structures and their geologic history of the Upper Ojai Valley of California can be reconstructed. The geometry of shallow structures, the geologic history, and the location of earthquake foci then offer constraints on the deep structure of this complex area. The Upper Ojai Valley is a tectonic depression between opposing reverse faults. Its northern border is formed by the active, north-dipping San Cayetano fault, which has 6.0 km of stratigraphic separation in the Silverthread area of the Ojai oil field andmore » 2.6 km of stratigraphic separation west of Sisar Creek. The fault dies out farther west in Ojai Valley, where the south-vergent shortening is transferred to a blind thrust. The southern border of the Upper Ojai Valley is formed by the Quaternary Lion fault set, which dips south and merges into the Sisar decollement within the south-dipping, ductile, lower Miocene Rincon formation. By the middle Pleistocene, the Sulphur Mountain anticlinorium and the Big Canyon syncline began forming as a fault-propagation fold; the fault-propagation fold is rooted in the Sisar decollement, a passive backthrust rising from a blind thrust at depth. The formation of the Sulphur Mountain anticlinorium was followed closely by the ramping of the south-dipping Lion fault set to the surface over the nonmarine upper Pleistocene Saugus Formation. To the east, the San Cayetano fault overrides and folds the Lion Fault set near the surface. Area-balancing of the deformation shows shortening of 15.5 km, and suggests a 17 km depth to the brittle-ductile transition.« less

  10. High-resolution seismic profiling reveals faulting associated with the 1934 Ms 6.6 Hansel Valley earthquake (Utah, USA)

    USGS Publications Warehouse

    Bruno, Pier Paolo G.; Duross, Christopher; Kokkalas, Sotirios

    2017-01-01

    The 1934 Ms 6.6 Hansel Valley, Utah, earthquake produced an 8-km-long by 3-km-wide zone of north-south−trending surface deformation in an extensional basin within the easternmost Basin and Range Province. Less than 0.5 m of purely vertical displacement was measured at the surface, although seismologic data suggest mostly strike-slip faulting at depth. Characterization of the origin and kinematics of faulting in the Hansel Valley earthquake is important to understand how complex fault ruptures accommodate regions of continental extension and transtension. Here, we address three questions: (1) How does the 1934 surface rupture compare with faults in the subsurface? (2) Are the 1934 fault scarps tectonic or secondary features? (3) Did the 1934 earthquake have components of both strike-slip and dip-slip motion? To address these questions, we acquired a 6.6-km-long, high-resolution seismic profile across Hansel Valley, including the 1934 ruptures. We observed numerous east- and west-dipping normal faults that dip 40°−70° and offset late Quaternary strata from within a few tens of meters of the surface down to a depth of ∼1 km. Spatial correspondence between the 1934 surface ruptures and subsurface faults suggests that ruptures associated with the earthquake are of tectonic origin. Our data clearly show complex basin faulting that is most consistent with transtensional tectonics. Although the kinematics of the 1934 earthquake remain underconstrained, we interpret the disagreement between surface (normal) and subsurface (strike-slip) kinematics as due to slip partitioning during fault propagation and to the effect of preexisting structural complexities. We infer that the 1934 earthquake occurred along an ∼3-km wide, off-fault damage zone characterized by distributed deformation along small-displacement faults that may be alternatively activated during different earthquake episodes.

  11. Research Spotlight: Groundwater is being depleted rapidly in California's Central Valley

    NASA Astrophysics Data System (ADS)

    Tretkoff, Ernie

    2011-03-01

    Groundwater is being depleted in California's Central Valley at a rapid rate, according to data from the Gravity Recovery and Climate Experiment (GRACE) satellite. Famiglietti et al. analyzed 78 months of GRACE data covering October 2003 to March 2010 to estimate water storage changes in California's Sacramento and San Joaquin river basins. They found that the basins are losing water at a rate of about 30 millimeters per year equivalent water height, or a total of about 30 cubic kilometers over the 78-month period. Furthermore, they found that two thirds of this loss, or a total of 20 cubic kilometers for the study period, came from groundwater depletion in the Central Valley. Quantifying groundwater depletion can be challenging in many areas because of a lack of monitoring infrastructure and reporting requirements; the study shows that satellite-based monitoring can be a useful way to track groundwater volumes. The authors warn that the current rate of groundwater depletion in the Central Valley may be unsustainable and could have “potentially dire consequences for the economic and food security of the United States.” (Geophysical Research Letters, doi:10.1029/2010GL046442, 2011)

  12. Volcanic unrest and hazard communication in Long Valley Volcanic Region, California

    USGS Publications Warehouse

    Hill, David P.; Mangan, Margaret T.; McNutt, Stephen R.

    2017-01-01

    The onset of volcanic unrest in Long Valley Caldera, California, in 1980 and the subsequent fluctuations in unrest levels through May 2016 illustrate: (1) the evolving relations between scientists monitoring the unrest and studying the underlying tectonic/magmatic processes and their implications for geologic hazards, and (2) the challenges in communicating the significance of the hazards to the public and civil authorities in a mountain resort setting. Circumstances special to this case include (1) the sensitivity of an isolated resort area to media hype of potential high-impact volcanic and earthquake hazards and its impact on potential recreational visitors and the local economy, (2) a small permanent population (~8000), which facilitates face-to-face communication between scientists monitoring the hazard, civil authorities, and the public, and (3) the relatively frequent turnover of people in positions of civil authority, which requires a continuing education effort on the nature of caldera unrest and related hazards. Because of delays associated with communication protocols between the State and Federal governments during the onset of unrest, local civil authorities and the public first learned that the U.S. Geological Survey was about to release a notice of potential volcanic hazards associated with earthquake activity and 25-cm uplift of the resurgent dome in the center of the caldera through an article in the Los Angeles Times published in May 1982. The immediate reaction was outrage and denial. Gradual acceptance that the hazard was real required over a decade of frequent meetings between scientists and civil authorities together with public presentations underscored by frequently felt earthquakes and the onset of magmatic CO2 emissions in 1990 following a 11-month long earthquake swarm beneath Mammoth Mountain on the southwest rim of the caldera. Four fatalities, one on 24 May 1998 and three on 6 April 2006, underscored the hazard posed by the CO2

  13. Rock-fall potential in the Yosemite Valley, California

    USGS Publications Warehouse

    Wieczorek, G.F.; Morrissey, M.M.; Iovine, Giulio; Godt, Jonathan

    1999-01-01

    We used two methods of estimating rock-fall potential in the Yosemite Valley, California based on (1) physical evidence of previous rock-fall travel, in which the potential extends to the base of the talus, and (2) theoretical potential energy considerations, in which the potential can extend beyond the base of the talus, herein referred to as the rock-fall shadow. Rock falls in the valley commonly range in size from individual boulders of less than 1 m3 to moderate-sized falls with volumes of about 100,000 m3. Larger rock falls exceeding 100,000 m3, referred to as rock avalanches, are considered to be much less likely to occur based on the relatively few prehistoric rock-fall avalanche deposits in the Yosemite Valley. Because the valley has steep walls and is relatively narrow, there are no areas that are absolutely safe from large rock avalanches. The map shows areas of rock-fall potential, but does not predict when or how frequently a rock fall will occur. Consequently, neither the hazard in terms of probability of a rock fall at any specific location, nor the risk to people or facilities to such events can be assessed from this map.

  14. 76 FR 67369 - Revisions to the California State Implementation Plan, Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-01

    ... the California State Implementation Plan, Joaquin Valley Unified Air Pollution Control District and Imperial County Air Pollution Control District AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: EPA is finalizing approval of revisions to the San Joaquin Valley Unified Air Pollution...

  15. Cruise report for A1-98-SC southern California Earthquake Hazards Project

    USGS Publications Warehouse

    Normark, William R.; Bohannon, Robert G.; Sliter, Ray; Dunhill, Gita; Scholl, David W.; Laursen, Jane; Reid, Jane A.; Holton, David

    1999-01-01

    The focus of the Southern California Earthquake Hazards project, within the Western Region Coastal and Marine Geology team (WRCMG), is to identify the landslide and earthquake hazards and related ground-deformation processes that can potentially impact the social and economic well-being of the inhabitants of the Southern California coastal region, the most populated urban corridor along the U.S. Pacific margin. The primary objective is to help mitigate the earthquake hazards for the Southern California region by improving our understanding of how deformation is distributed (spatially and temporally) in the offshore with respect to the onshore region. To meet this overall objective, we are investigating the distribution, character, and relative intensity of active (i.e., primarily Holocene) deformation within the basins and along the shelf adjacent to the most highly populated areas (see Fig. 1). In addition, the project will examine the Pliocene-Pleistocene record of how this deformation has shifted in space and time. The results of this study should improve our knowledge of shifting deformation for both the long-term (105 to several 106 yr) and short-term (<50 ky) time frames and enable us to identify actively deforming structures that may constitute current significant seismic hazards.

  16. History of Modern Earthquake Hazard Mapping and Assessment in California Using a Deterministic or Scenario Approach

    NASA Astrophysics Data System (ADS)

    Mualchin, Lalliana

    2011-03-01

    Modern earthquake ground motion hazard mapping in California began following the 1971 San Fernando earthquake in the Los Angeles metropolitan area of southern California. Earthquake hazard assessment followed a traditional approach, later called Deterministic Seismic Hazard Analysis (DSHA) in order to distinguish it from the newer Probabilistic Seismic Hazard Analysis (PSHA). In DSHA, seismic hazard in the event of the Maximum Credible Earthquake (MCE) magnitude from each of the known seismogenic faults within and near the state are assessed. The likely occurrence of the MCE has been assumed qualitatively by using late Quaternary and younger faults that are presumed to be seismogenic, but not when or within what time intervals MCE may occur. MCE is the largest or upper-bound potential earthquake in moment magnitude, and it supersedes and automatically considers all other possible earthquakes on that fault. That moment magnitude is used for estimating ground motions by applying it to empirical attenuation relationships, and for calculating ground motions as in neo-DSHA (Z uccolo et al., 2008). The first deterministic California earthquake hazard map was published in 1974 by the California Division of Mines and Geology (CDMG) which has been called the California Geological Survey (CGS) since 2002, using the best available fault information and ground motion attenuation relationships at that time. The California Department of Transportation (Caltrans) later assumed responsibility for printing the refined and updated peak acceleration contour maps which were heavily utilized by geologists, seismologists, and engineers for many years. Some engineers involved in the siting process of large important projects, for example, dams and nuclear power plants, continued to challenge the map(s). The second edition map was completed in 1985 incorporating more faults, improving MCE's estimation method, and using new ground motion attenuation relationships from the latest published

  17. Uncertainties in Earthquake Loss Analysis: A Case Study From Southern California

    NASA Astrophysics Data System (ADS)

    Mahdyiar, M.; Guin, J.

    2005-12-01

    Probabilistic earthquake hazard and loss analyses play important roles in many areas of risk management, including earthquake related public policy and insurance ratemaking. Rigorous loss estimation for portfolios of properties is difficult since there are various types of uncertainties in all aspects of modeling and analysis. It is the objective of this study to investigate the sensitivity of earthquake loss estimation to uncertainties in regional seismicity, earthquake source parameters, ground motions, and sites' spatial correlation on typical property portfolios in Southern California. Southern California is an attractive region for such a study because it has a large population concentration exposed to significant levels of seismic hazard. During the last decade, there have been several comprehensive studies of most regional faults and seismogenic sources. There have also been detailed studies on regional ground motion attenuations and regional and local site responses to ground motions. This information has been used by engineering seismologists to conduct regional seismic hazard and risk analysis on a routine basis. However, one of the more difficult tasks in such studies is the proper incorporation of uncertainties in the analysis. From the hazard side, there are uncertainties in the magnitudes, rates and mechanisms of the seismic sources and local site conditions and ground motion site amplifications. From the vulnerability side, there are considerable uncertainties in estimating the state of damage of buildings under different earthquake ground motions. From an analytical side, there are challenges in capturing the spatial correlation of ground motions and building damage, and integrating thousands of loss distribution curves with different degrees of correlation. In this paper we propose to address some of these issues by conducting loss analyses of a typical small portfolio in southern California, taking into consideration various source and ground

  18. On the reported ionospheric precursor of the Hector Mine, California earthquake

    USGS Publications Warehouse

    Thomas, J.N.; Love, J.J.; Komjathy, A.; Verkhoglyadova, O.P.; Butala, M.; Rivera, N.

    2012-01-01

    Using Global Positioning System (GPS) data from sites near the 16 Oct. 1999 Hector Mine, California earthquake, Pulinets et al. (2007) identified anomalous changes in the ionospheric total electron content (TEC) starting one week prior to the earthquake. Pulinets (2007) suggested that precursory phenomena of this type could be useful for predicting earthquakes. On the other hand, and in a separate analysis, Afraimovich et al. (2004) concluded that TEC variations near the epicenter were controlled by solar and geomagnetic activity that were unrelated to the earthquake. In an investigation of these very different results, we examine TEC time series of long duration from GPS stations near and far from the epicenter of the Hector Mine earthquake, and long before and long after the earthquake. While we can reproduce the essential time series results of Pulinets et al., we find that the signal they identified as being anomalous is not actually anomalous. Instead, it is just part of normal global-scale TEC variation. We conclude that the TEC anomaly reported by Pulinets et al. is unrelated to the Hector Mine earthquake.

  19. SRTM Perspective View with Landsat Overlay: San Joaquin Valley, California

    NASA Technical Reports Server (NTRS)

    2000-01-01

    San Joaquin, the name given to the southern portion of California's vast Central Valley, has been called the world's richest agricultural valley. In this perspective view generated using data from the Shuttle Radar Topography Mission and an enhanced Landsat image, we are looking toward the southwest over a checkerboard pattern of agricultural fields. Mt. Pinos, a popular location for stargazing at 2,692 meters (8,831 feet) looms above the valley floor and is visible on the left side of the image. The productive southern San Joaquin is in reality a desert, averaging less than 12.7 cm (5 inches) of rain per year. Through canals and irrigation, the region nurtures some two hundred crops including grapes, figs, apricots, oranges, and more than 4,047 square-km (1,000,000 acres) of cotton. The California Aqueduct, transporting water from the Sacramento River Delta through the San Joaquin, runs along the base of the low-lying Wheeler Ridge on the left side of the image. The valley is not all agriculture though. Kern County, near the valley's southern end, is the United States' number one oil producing county, and actually produces more crude oil than Oklahoma. For visualization purposes, topographic heights displayed in this image are exaggerated two times. Colors, from Landsat data, approximate natural color.

    The elevation data used in this image was acquired by SRTM aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of Earth's land surface. To collect the 3-D SRTM data, engineers added a mast 60 meters (about 200 feet)long, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the NASA, the National Imagery and Mapping Agency (NIMA) of the U

  20. Earthquake potential in California-Nevada implied by correlation of strain rate and seismicity

    USGS Publications Warehouse

    Zeng, Yuehua; Petersen, Mark D.; Shen, Zheng-Kang

    2018-01-01

    Rock mechanics studies and dynamic earthquake simulations show that patterns of seismicity evolve with time through (1) accumulation phase, (2) localization phase, and (3) rupture phase. We observe a similar pattern of changes in seismicity during the past century across California and Nevada. To quantify these changes, we correlate GPS strain rates with seismicity. Earthquakes of M > 6.5 are collocated with regions of highest strain rates. By contrast, smaller magnitude earthquakes of M ≥ 4 show clear spatiotemporal changes. From 1933 to the late 1980s, earthquakes of M ≥ 4 were more diffused and broadly distributed in both high and low strain rate regions (accumulation phase). From the late 1980s to 2016, earthquakes were more concentrated within the high strain rate areas focused on the major fault strands (localization phase). In the same time period, the rate of M > 6.5 events also increased significantly in the high strain rate areas. The strong correlation between current strain rate and the later period of seismicity indicates that seismicity is closely related to the strain rate. The spatial patterns suggest that before the late 1980s, the strain rate field was also broadly distributed because of the stress shadows from previous large earthquakes. As the deformation field evolved out of the shadow in the late 1980s, strain has refocused on the major fault systems and we are entering a period of increased risk for large earthquakes in California.

  1. Earthquake Potential in California-Nevada Implied by Correlation of Strain Rate and Seismicity

    NASA Astrophysics Data System (ADS)

    Zeng, Yuehua; Petersen, Mark D.; Shen, Zheng-Kang

    2018-02-01

    Rock mechanics studies and dynamic earthquake simulations show that patterns of seismicity evolve with time through (1) accumulation phase, (2) localization phase, and (3) rupture phase. We observe a similar pattern of changes in seismicity during the past century across California and Nevada. To quantify these changes, we correlate GPS strain rates with seismicity. Earthquakes of M > 6.5 are collocated with regions of highest strain rates. By contrast, smaller magnitude earthquakes of M ≥ 4 show clear spatiotemporal changes. From 1933 to the late 1980s, earthquakes of M ≥ 4 were more diffused and broadly distributed in both high and low strain rate regions (accumulation phase). From the late 1980s to 2016, earthquakes were more concentrated within the high strain rate areas focused on the major fault strands (localization phase). In the same time period, the rate of M > 6.5 events also increased significantly in the high strain rate areas. The strong correlation between current strain rate and the later period of seismicity indicates that seismicity is closely related to the strain rate. The spatial patterns suggest that before the late 1980s, the strain rate field was also broadly distributed because of the stress shadows from previous large earthquakes. As the deformation field evolved out of the shadow in the late 1980s, strain has refocused on the major fault systems and we are entering a period of increased risk for large earthquakes in California.

  2. Elastic-wave propagation and site amplification in the Salt Lake Valley, Utah, from simulated normal faulting earthquakes

    USGS Publications Warehouse

    Benz, H.M.; Smith, R.B.

    1988-01-01

    The two-dimensional seismic response of the Salt Lake valley to near- and far-field earthquakes has been investigated from simulations of vertically incident plane waves and from normal-faulting earthquakes generated on the basin-bounding Wasatch fault. The plane-wave simulations were compared with observed site amplifications in the Salt Lake valley, based on seismic recordings from nuclear explosions in southern Nevada, that show 10 times greater amplification with the basin than measured values on hard-rock sites. Synthetic seismograms suggest that in the frequency band 0.3 to 1.5 Hz at least one-half the site amplitication can be attributed to the impedance contrast between the basin sediments and higher velocity basement rocks. -from Authors

  3. Dynamic models of an earthquake and tsunami offshore Ventura, California

    USGS Publications Warehouse

    Kenny J. Ryan,; Geist, Eric L.; Barall, Michael; David D. Oglesby,

    2015-01-01

    The Ventura basin in Southern California includes coastal dip-slip faults that can likely produce earthquakes of magnitude 7 or greater and significant local tsunamis. We construct a 3-D dynamic rupture model of an earthquake on the Pitas Point and Lower Red Mountain faults to model low-frequency ground motion and the resulting tsunami, with a goal of elucidating the seismic and tsunami hazard in this area. Our model results in an average stress drop of 6 MPa, an average fault slip of 7.4 m, and a moment magnitude of 7.7, consistent with regional paleoseismic data. Our corresponding tsunami model uses final seafloor displacement from the rupture model as initial conditions to compute local propagation and inundation, resulting in large peak tsunami amplitudes northward and eastward due to site and path effects. Modeled inundation in the Ventura area is significantly greater than that indicated by state of California's current reference inundation line.

  4. Induced dynamic nonlinear ground response at Gamer Valley, California

    USGS Publications Warehouse

    Lawrence, Z.; Bodin, P.; Langston, C.A.; Pearce, F.; Gomberg, J.; Johnson, P.A.; Menq, F.-Y.; Brackman, T.

    2008-01-01

    We present results from a prototype experiment in which we actively induce, observe, and quantify in situ nonlinear sediment response in the near surface. This experiment was part of a suite of experiments conducted during August 2004 in Garner Valley, California, using a large mobile shaker truck from the Network for Earthquake Engineering Simulation (NEES) facility. We deployed a dense accelerometer array within meters of the mobile shaker truck to replicate a controlled, laboratory-style soil dynamics experiment in order to observe wave-amplitude-dependent sediment properties. Ground motion exceeding 1g acceleration was produced near the shaker truck. The wave field was dominated by Rayleigh surface waves and ground motions were strong enough to produce observable nonlinear changes in wave velocity. We found that as the force load of the shaker increased, the Rayleigh-wave phase velocity decreased by as much as ???30% at the highest frequencies used (up to 30 Hz). Phase velocity dispersion curves were inverted for S-wave velocity as a function of depth using a simple isotropic elastic model to estimate the depth dependence of changes to the velocity structure. The greatest change in velocity occurred nearest the surface, within the upper 4 m. These estimated S-wave velocity values were used with estimates of surface strain to compare with laboratory-based shear modulus reduction measurements from the same site. Our results suggest that it may be possible to characterize nonlinear soil properties in situ using a noninvasive field technique.

  5. Fluid-faulting evolution in high definition: Connecting fault structure and frequency-magnitude variations during the 2014 Long Valley Caldera, California earthquake swarm

    USGS Publications Warehouse

    Shelly, David R.; Ellsworth, William L.; Hill, David P.

    2016-01-01

    An extended earthquake swarm occurred beneath southeastern Long Valley Caldera between May and November 2014, culminating in three magnitude 3.5 earthquakes and 1145 cataloged events on 26 September alone. The swarm produced the most prolific seismicity in the caldera since a major unrest episode in 1997-1998. To gain insight into the physics controlling swarm evolution, we used large-scale cross-correlation between waveforms of cataloged earthquakes and continuous data, producing precise locations for 8494 events, more than 2.5 times the routine catalog. We also estimated magnitudes for 18,634 events (~5.5 times the routine catalog), using a principal component fit to measure waveform amplitudes relative to cataloged events. This expanded and relocated catalog reveals multiple episodes of pronounced hypocenter expansion and migration on a collection of neighboring faults. Given the rapid migration and alignment of hypocenters on narrow faults, we infer that activity was initiated and sustained by an evolving fluid pressure transient with a low-viscosity fluid, likely composed primarily of water and CO2 exsolved from underlying magma. Although both updip and downdip migration were observed within the swarm, downdip activity ceased shortly after activation, while updip activity persisted for weeks at moderate levels. Strongly migrating, single-fault episodes within the larger swarm exhibited a higher proportion of larger earthquakes (lower Gutenberg-Richter b value), which may have been facilitated by fluid pressure confined in two dimensions within the fault zone. In contrast, the later swarm activity occurred on an increasingly diffuse collection of smaller faults, with a much higher b value.

  6. 77 FR 5709 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-06

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of the... pollution control, Incorporation by reference, Intergovernmental relations, Nitrogen dioxide, Ozone...

  7. 77 FR 2496 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-18

    ... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 52 [EPA-R09-OAR-2011-0987; FRL-9617-5] Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management District and Imperial... rule. SUMMARY: EPA is proposing to approve revisions to the Antelope Valley Air Quality Management...

  8. 78 FR 49992 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-16

    ... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 52 [EPA-R09-OAR-2013-0394; FRL-9845-4] Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management District and Ventura... rule. SUMMARY: EPA is proposing to approve revisions to the Antelope Valley Air Quality Management...

  9. Rumours about the Po Valley earthquakes of 20th and 29th May 2012

    NASA Astrophysics Data System (ADS)

    La Longa, Federica; Crescimbene, Massimo; Camassi, Romano; Nostro, Concetta

    2013-04-01

    The history of rumours is as old as human history. Even in remote antiquity, rumours, gossip and hoax were always in circulation - in good or bad faith - to influence human affairs. Today with the development of mass media, rise of the internet and social networks, rumours are ubiquitous. The earthquakes, because of their characteristics of strong emotional impact and unpredictability, are among the natural events that more cause the birth and the spread of rumours. For this reason earthquakes that occurred in the Po valley the 20th and 29th May 2012 generated and still continue to generate a wide variety of rumours regarding issues related to the earthquake, its effects, the possible causes, future predictions. For this reason, as occurred during the L'Aquila earthquake sequence in 2009, following the events of May 2012 in Emilia Romagna was created a complex initiative training and information that at various stages between May and September 2012, involved population, partly present in the camp, and then the school staff of the municipalities affected by the earthquake. This experience has been organized and managed by the Department of Civil Protection (DPC), the National Institute of Geophysics and Volcanology (INGV), the Emilia Romagna region in collaboration with the Network of University Laboratories for Earthquake Engineering (RELUIS), the Health Service Emilia Romagna Regional and voluntary organizations of civil protection in the area. Within this initiative, in the period June-September 2012 were collected and catalogued over 240 rumours. In this work rumours of the Po Valley are studied in their specific characteristics and strategies and methods to fight them are also discussed. This work of collection and discussion of the rumours was particularly important to promote good communication strategies and to fight the spreading of the rumours. Only in this way it was possible to create a full intervention able to supporting both the local institutions and

  10. Strong Motion Network of Medellín and Aburrá Valley: technical advances, seismicity records and micro-earthquake monitoring

    NASA Astrophysics Data System (ADS)

    Posada, G.; Trujillo, J. C., Sr.; Hoyos, C.; Monsalve, G.

    2017-12-01

    The tectonics setting of Colombia is determined by the interaction of Nazca, Caribbean and South American plates, together with the Panama-Choco block collision, which makes a seismically active region. Regional seismic monitoring is carried out by the National Seismological Network of Colombia and the Accelerometer National Network of Colombia. Both networks calculate locations, magnitudes, depths and accelerations, and other seismic parameters. The Medellín - Aburra Valley is located in the Northern segment of the Central Cordillera of Colombia, and according to the Colombian technical seismic norm (NSR-10), is a region of intermediate hazard, because of the proximity to seismic sources of the Valley. Seismic monitoring in the Aburra Valley began in 1996 with an accelerometer network which consisted of 38 instruments. Currently, the network consists of 26 stations and is run by the Early Warning System of Medellin and Aburra Valley (SIATA). The technical advances have allowed the real-time communication since a year ago, currently with 10 stations; post-earthquake data is processed through operationally near-real-time, obtaining quick results in terms of location, acceleration, spectrum response and Fourier analysis; this information is displayed at the SIATA web site. The strong motion database is composed by 280 earthquakes; this information is the basis for the estimation of seismic hazards and risk for the region. A basic statistical analysis of the main information was carried out, including the total recorded events per station, natural frequency, maximum accelerations, depths and magnitudes, which allowed us to identify the main seismic sources, and some seismic site parameters. With the idea of a more complete seismic monitoring and in order to identify seismic sources beneath the Valley, we are in the process of installing 10 low-cost shake seismometers for micro-earthquake monitoring. There is no historical record of earthquakes with a magnitude

  11. Delineation of faulting and basin geometry along a seismic reflection transect in urbanized San Bernardino Valley, California

    USGS Publications Warehouse

    Stephenson, W.J.; Odum, J.K.; Williams, R.A.; Anderson, M.L.

    2002-01-01

    Fourteen kilometers of continuous, shallow seismic reflection data acquired through the urbanized San Bernardino Valley, California, have revealed numerous faults between the San Jacinto and San Andreas faults as well as a complex pattern of downdropped and uplifted blocks. These data also indicate that the Loma Linda fault continues northeastward at least 4.5 km beyond its last mapped location on the southern edge of the valley and to within at least 2 km of downtown San Bernardino. Previously undetected faults within the valley northeast of the San Jacinto fault are also imaged, including the inferred western extension of the Banning fault and several unnamed faults. The Rialto-Colton fault is interpreted southwest of the San Jacinto fault. The seismic data image the top of the crystalline basement complex across 70% of the profile length and show that the basement has an overall dip of roughly 10?? southwest between Perris Hill and the San Jacinto fault. Gravity and aeromagnetic data corroborate the interpreted location of the San Jacinto fault and better constrain the basin depth along the seismic profile to be as deep as 1.7 km. These data also corroborate other fault locations and the general dip of the basement surface. At least 1.2 km of apparent vertical displacement on the basement is observed across the San Jacinto fault at the profile location. The basin geometry delineated by these data was used to generate modeled ground motions that show peak horizontal amplifications of 2-3.5 above bedrock response in the 0.05- to 1.0-Hz frequency band, which is consistent with recorded earthquake data in the valley.

  12. 76 FR 70886 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-16

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of the... CFR Part 52 Environmental protection, Air pollution control, Incorporation by reference...

  13. 76 FR 33181 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-08

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... approve a revision to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of..., Air pollution control, Intergovernmental relations, Ozone, Reporting and recordkeeping requirements...

  14. 76 FR 5276 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-31

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of the... protection, Air pollution control, Incorporation by reference, Intergovernmental relations, Nitrogen dioxide...

  15. MMI attenuation and historical earthquakes in the basin and range province of western North America

    USGS Publications Warehouse

    Bakun, W.H.

    2006-01-01

    Earthquakes in central Nevada (1932-1959) were used to develop a modified Mercalli intensity (MMI) attenuation model for estimating moment magnitude M for earthquakes in the Basin and Range province of interior western North America. M is 7.4-7.5 for the 26 March 1872 Owens Valley, California, earthquake, in agreement with Beanland and Clark's (1994) M 7.6 that was estimated from geologic field observations. M is 7.5 for the 3 May 1887 Sonora, Mexico, earthquake, in agreement with Natali and Sbar's (1982) M 7.4 and Suter's (2006) M 7.5, both estimated from geologic field observations. MMI at sites in California for earthquakes in the Nevada Basin and Range apparently are not much affected by the Sierra Nevada except at sites near the Sierra Nevada where MMI is reduced. This reduction in MMI is consistent with a shadow zone produced by the root of the Sierra Nevada. In contrast, MMI assignments for earthquakes located in the eastern Sierra Nevada near the west margin of the Basin and Range are greater than predicted at sites in California. These higher MMI values may result from critical reflections due to layering near the base of the Sierra Nevada.

  16. Observation of the seismic nucleation phase in the Ridgecrest, California, earthquake sequence

    USGS Publications Warehouse

    Ellsworth, W.L.; Beroza, G.C.

    1998-01-01

    Near-source observations of five M 3.8-5.2 earthquakes near Ridgecrest, California are consistent with the presence of a seismic nucleation phase. These earthquakes start abruptly, but then slow or stop before rapidly growing again toward their maximum rate of moment release. Deconvolution of instrument and path effects by empirical Green's functions demonstrates that the initial complexity at the start of the earthquake is a source effect. The rapid growth of the P-wave arrival at the start of the seismic nucleation phase supports the conclusion of Mori and Kanamori [1996] that these earthquakes begin without a magnitude-scaled slow initial phase of the type observed by Iio [1992, 1995].

  17. Initial rupture of earthquakes in the 1995 Ridgecrest, California sequence

    USGS Publications Warehouse

    Mori, J.; Kanamori, H.

    1996-01-01

    Close examination of the P waves from earthquakes ranging in size across several orders of magnitude shows that the shape of the initiation of the velocity waveforms is independent of the magnitude of the earthquake. A model in which earthquakes of all sizes have similar rupture initiation can explain the data. This suggests that it is difficult to estimate the eventual size of an earthquake from the initial portion of the waveform. Previously reported curvature seen in the beginning of some velocity waveforms can be largely explained as the effect of anelastic attenuation; thus there is little evidence for a departure from models of simple rupture initiation that grow dynamically from a small region. The results of this study indicate that any "precursory" radiation at seismic frequencies must emanate from a source region no larger than the equivalent of a M0.5 event (i.e. a characteristic length of ???10 m). The size of the nucleation region for magnitude 0 to 5 earthquakes thus is not resolvable with the standard seismic instrumentation deployed in California. Copyright 1996 by the American Geophysical Union.

  18. Products and Services Available from the Southern California Earthquake Data Center (SCEDC) and the Southern California Seismic Network (SCSN)

    NASA Astrophysics Data System (ADS)

    Yu, E.; Chen, S.; Chowdhury, F.; Bhaskaran, A.; Hutton, K.; Given, D.; Hauksson, E.; Clayton, R. W.

    2009-12-01

    The SCEDC archives continuous and triggered data from nearly 3000 data channels from 375 SCSN recorded stations. The SCSN and SCEDC process and archive an average of 12,000 earthquakes each year, contributing to the southern California earthquake catalog that spans from 1932 to present. The SCEDC provides public, searchable access to these earthquake parametric and waveform data through its website www.data.scec.org and through client applications such as STP, NETDC and DHI. New data products: ● The SCEDC is distributing synthetic waveform data from the 2008 ShakeOut scenario (Jones et al., USGS Open File Rep., 2008-1150) and (Graves et al. 2008; Geophys. Res. Lett.) This is a M 7.8 earthquake on the southern San Andreas fault. Users will be able to download 40 sps velocity waveforms in SAC format from the SCEDC website. The SCEDC is also distributing synthetic GPS data (Crowell et al., 2009; Seismo. Res. Letters.) for this scenario as well. ● The SCEDC has added a new web page to show the latest tomographic model of Southern California. This model is based on Tape et al., 2009 Science. New data services: ● The SCEDC is exporting data in QuakeML format. This is an xml format that has been adopted by the Advanced National Seismic System (ANSS). This data will also be available as a web service. ● The SCEDC is exporting data in StationXML format. This is an xml format created by the SCEDC and adopted by ANSS to fully describe station metadata. This data will also be available as a web service. ● The stp 1.6 client can now access both the SCEDC and the Northern California Earthquake Data Center (NCEDC) earthquake and waveform archives. In progress - SCEDC to distribute 1 sps GPS data in miniSEED format: ● As part of a NASA Advanced Information Systems Technology project in collaboration with Jet Propulsion Laboratory and Scripps Institution of Oceanography, the SCEDC will receive real time 1 sps streams of GPS displacement solutions from the California

  19. Aquifer-test compilation for the San Joaquin Valley, California

    USGS Publications Warehouse

    McClelland, E.J.

    1962-01-01

    This report is the first of a series the purpose of which is to make available in standard tabular form the results of aquifer tests that have been made by various private and public agencies in California. The scope of the compilation is to describe systematically, in a form agreed upon by the California Department of Water Resources and the Geological Survey, the (1) test location, (2) pumping data, (3) well data, and (4) summary of results. The results of these tests sometimes have been published but most frequently have been used only as a step in obtaining other information, consequently the results and even the location of aquifer tests have not been readily available.This report has been prepared by the Geological Survey under the immediate supervision of Fred Kunkel, district geologist for California, in cooperation with the California Department of Water Resources, and tabulates through October 1962 all tests analyzed by the Geological Survey for the San Joaquin Valley. The report is designed to be expanded when additional tests are analyzed or new tests are made.

  20. 76 FR 37044 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-24

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... approve revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of... Glass Manufacturing'', US EPA, June 1994. 7. ``Integrated Pollution Prevention and Control (IPPC...

  1. 77 FR 66429 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-05

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... approve revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of... 1994. 11. ``Integrated Pollution Prevention and Control (IPPC) Reference Document on Best Available...

  2. 76 FR 40660 - Revisions to the California State Implementation Plan, San Joaquin Valley Air Pollution Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-11

    ... the California State Implementation Plan, San Joaquin Valley Air Pollution Control District (SJVUAPCD... approve revisions to the San Joaquin Valley Air Pollution Control District (SJVUAPCD) portion of the....0 for the following terms: Air Pollution Control Officer, Board, Environmental Protection Agency...

  3. 77 FR 24883 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-26

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... approve revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of... of Subjects in 40 CFR Part 52 Environmental protection, Air pollution control, Intergovernmental...

  4. 76 FR 52623 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-23

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... approve revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of... Subjects in 40 CFR Part 52 Environmental protection, Air pollution control, Intergovernmental relations...

  5. 76 FR 56706 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-14

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... approve revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of... of Subjects in 40 CFR Part 52 Environmental protection, Air pollution control, Intergovernmental...

  6. 77 FR 35329 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-13

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... approve revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of... of Subjects in 40 CFR Part 52 Environmental protection, Air pollution control, Intergovernmental...

  7. The Loma Prieta earthquake of October 17, 1989 : a brief geologic view of what caused the Loma Prieta earthquake and implications for future California earthquakes: What happened ... what is expected ... what can be done.

    USGS Publications Warehouse

    Ward, Peter L.; Page, Robert A.

    1990-01-01

    The San Andreas fault, in California, is the primary boundary between the North American plate and the Pacific plate. Land west of the fault has been moving northwestward relative to land on the east at an average rate of 2 inches per year for millions of years. This motion is not constant but occurs typically in sudden jumps during large earthquakes. This motion is relentless; therefore earthquakes in California are inevitable.

  8. Imperial Valley and Salton Sea, California

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Southern California's Salton Sea is a prominent visual for astronauts. This large lake supports the rich agricultural fields of the Imperial, Coachella and Mexicali Valleys in the California and Mexico desert. The Salton Sea formed by accident in 1905 when an irrigation canal ruptured, allowing the Colorado River to flood the Salton Basin. Today the Sea performs an important function as the sink for agricultural runoff; water levels are maintained by the runoff from the surrounding agricultural valleys. The Salton Sea salinity is high-nearly 1/4 saltier than ocean water-but it remains an important stopover point for migratory water birds, including several endangered species. The region also experiences several environmental problems. The recent increased demands for the limited Colorado River water threatens the amount of water allowed to flow into the Salton Sea. Increased salinity and decreased water levels could trigger several regional environmental crises. The agricultural flow into the Sea includes nutrients and agricultural by-products, increasing the productivity and likelihood of algae blooms. This image shows either a bloom, or suspended sediment (usually highly organic) in the water that has been stirred up by winds. Additional information: The Salton Sea A Brief Description of Its Current Conditions, and Potential Remediation Projects and Land Use Across the U.S.-Mexico Border Astronaut photograph STS111-E-5224 was taken by the STS-111 Space Shuttle crew that recently returned from the International Space Station. The image was taken June 12, 2002 using a digital camera. The image was provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

  9. Distributing Earthquakes Among California's Faults: A Binary Integer Programming Approach

    NASA Astrophysics Data System (ADS)

    Geist, E. L.; Parsons, T.

    2016-12-01

    Statement of the problem is simple: given regional seismicity specified by a Gutenber-Richter (G-R) relation, how are earthquakes distributed to match observed fault-slip rates? The objective is to determine the magnitude-frequency relation on individual faults. The California statewide G-R b-value and a-value are estimated from historical seismicity, with the a-value accounting for off-fault seismicity. UCERF3 consensus slip rates are used, based on geologic and geodetic data and include estimates of coupling coefficients. The binary integer programming (BIP) problem is set up such that each earthquake from a synthetic catalog spanning millennia can occur at any location along any fault. The decision vector, therefore, consists of binary variables, with values equal to one indicating the location of each earthquake that results in an optimal match of slip rates, in an L1-norm sense. Rupture area and slip associated with each earthquake are determined from a magnitude-area scaling relation. Uncertainty bounds on the UCERF3 slip rates provide explicit minimum and maximum constraints to the BIP model, with the former more important to feasibility of the problem. There is a maximum magnitude limit associated with each fault, based on fault length, providing an implicit constraint. Solution of integer programming problems with a large number of variables (>105 in this study) has been possible only since the late 1990s. In addition to the classic branch-and-bound technique used for these problems, several other algorithms have been recently developed, including pre-solving, sifting, cutting planes, heuristics, and parallelization. An optimal solution is obtained using a state-of-the-art BIP solver for M≥6 earthquakes and California's faults with slip-rates > 1 mm/yr. Preliminary results indicate a surprising diversity of on-fault magnitude-frequency relations throughout the state.

  10. Satellites measure recent rates of groundwater depletion in California's Central Valley

    NASA Astrophysics Data System (ADS)

    Famiglietti, J. S.; Lo, M.; Ho, S. L.; Bethune, J.; Anderson, K. J.; Syed, T. H.; Swenson, S. C.; de Linage, C. R.; Rodell, M.

    2011-02-01

    In highly-productive agricultural areas such as California's Central Valley, where groundwater often supplies the bulk of the water required for irrigation, quantifying rates of groundwater depletion remains a challenge owing to a lack of monitoring infrastructure and the absence of water use reporting requirements. Here we use 78 months (October, 2003-March, 2010) of data from the Gravity Recovery and Climate Experiment satellite mission to estimate water storage changes in California's Sacramento and San Joaquin River Basins. We find that the basins are losing water at a rate of 31.0 ± 2.7 mm yr-1 equivalent water height, equal to a volume of 30.9 km3 for the study period, or nearly the capacity of Lake Mead, the largest reservoir in the United States. We use additional observations and hydrological model information to determine that the majority of these losses are due to groundwater depletion in the Central Valley. Our results show that the Central Valley lost 20.4 ± 3.9 mm yr-1 of groundwater during the 78-month period, or 20.3 km3 in volume. Continued groundwater depletion at this rate may well be unsustainable, with potentially dire consequences for the economic and food security of the United States.

  11. Long-term fault creep observations in central California

    NASA Astrophysics Data System (ADS)

    Schulz, Sandra S.; Mavko, Gerald M.; Burford, Robert O.; Stuart, William D.

    1982-08-01

    The U.S. Geological Survey (USGS) has been monitoring aseismic fault slip in central California for more than 10 years as part of an earthquake prediction experiment. Since 1968, the USGS creep network has grown from one creep meter at the Cienega Winery south of Hollister to a 44-station network that stretches from Hayward, east of San Francisco Bay, to Palmdale in southern California. In general, the long-term slip pattern is most variable on sections of the faults where several magnitude 4 and larger earthquakes occurred during the recording period (e.g., Calaveras fault near Hollister and San Andreas fault between San Juan Bautista and Bear Valley). These fault sections are the most difficult to characterize with a single long-term slip rate. In contrast, sections of the faults that are seismically relatively quiet (e.g., San Andreas fault between Bear Valley and Parkfield) produce the steadiest creep records and are easiest to fit with a single long-term slip rate. Appendix is available with entire article on microfiche. Order from the American Geophysical Union, 2000 Florida Avenue, N.W., Washington, D.C. 20009. Document J82-004; $1.00. Payment must accompany order.

  12. The 1868 Hayward fault, California, earthquake: Implications for earthquake scaling relations on partially creeping faults

    USGS Publications Warehouse

    Hough, Susan E.; Martin, Stacey

    2015-01-01

    The 21 October 1868 Hayward, California, earthquake is among the best-characterized historical earthquakes in California. In contrast to many other moderate-to-large historical events, the causative fault is clearly established. Published magnitude estimates have been fairly consistent, ranging from 6.8 to 7.2, with 95% confidence limits including values as low as 6.5. The magnitude is of particular importance for assessment of seismic hazard associated with the Hayward fault and, more generally, to develop appropriate magnitude–rupture length scaling relations for partially creeping faults. The recent reevaluation of archival accounts by Boatwright and Bundock (2008), together with the growing volume of well-calibrated intensity data from the U.S. Geological Survey “Did You Feel It?” (DYFI) system, provide an opportunity to revisit and refine the magnitude estimate. In this study, we estimate the magnitude using two different methods that use DYFI data as calibration. Both approaches yield preferred magnitude estimates of 6.3–6.6, assuming an average stress drop. A consideration of data limitations associated with settlement patterns increases the range to 6.3–6.7, with a preferred estimate of 6.5. Although magnitude estimates for historical earthquakes are inevitably uncertain, we conclude that, at a minimum, a lower-magnitude estimate represents a credible alternative interpretation of available data. We further discuss implications of our results for probabilistic seismic-hazard assessment from partially creeping faults.

  13. Hydrothermal response to a volcano-tectonic earthquake swarm, Lassen, California

    USGS Publications Warehouse

    Ingebritsen, Steven E.; Shelly, David R.; Hsieh, Paul A.; Clor, Laura; P.H. Seward,; Evans, William C.

    2015-01-01

    The increasing capability of seismic, geodetic, and hydrothermal observation networks allows recognition of volcanic unrest that could previously have gone undetected, creating an imperative to diagnose and interpret unrest episodes. A November 2014 earthquake swarm near Lassen Volcanic National Park, California, which included the largest earthquake in the area in more than 60 years, was accompanied by a rarely observed outburst of hydrothermal fluids. Although the earthquake swarm likely reflects upward migration of endogenous H2O-CO2 fluids in the source region, there is no evidence that such fluids emerged at the surface. Instead, shaking from the modest sized (moment magnitude 3.85) but proximal earthquake caused near-vent permeability increases that triggered increased outflow of hydrothermal fluids already present and equilibrated in a local hydrothermal aquifer. Long-term, multiparametric monitoring at Lassen and other well-instrumented volcanoes enhances interpretation of unrest and can provide a basis for detailed physical modeling.

  14. Cascadia Earthquake and Tsunami Scenario for California's North Coast

    NASA Astrophysics Data System (ADS)

    Dengler, L.

    2006-12-01

    In 1995 the California Division of Mines and Geology (now the California Geological Survey) released a planning scenario for an earthquake on the southern portion of the Cascadia subduction zone (CSZ). This scenario was the 8th and last of the Earthquake Planning Scenarios published by CDMG. It was the largest magnitude CDMG scenario, an 8.4 earthquake rupturing the southern 200 km of the CSZ, and it was the only scenario to include tsunami impacts. This scenario event has not occurred in historic times and depicts impacts far more severe than any recent earthquake. The local tsunami hazard is new; there is no written record of significant local tsunami impact in the region. The north coast scenario received considerable attention in Humboldt and Del Norte Counties and contributed to a number of mitigation efforts. The Redwood Coast Tsunami Work Group (RCTWG), an organization of scientists, emergency managers, government agencies, and businesses from Humboldt, Mendocino, and Del Norte Counties, was formed in 1996 to assist local jurisdictions in understanding the implications of the scenario and to promote a coordinated, consistent mitigation program. The group has produced print and video materials and promoted response and evacuation planning. Since 1997 the RCTWG has sponsored an Earthquake Tsunami Education Room at county fairs featuring preparedness information, hands-on exhibits and regional tsunami hazard maps. Since the development of the TsunamiReady Program in 2001, the RCTWG facilitates community TsunamiReady certification. To assess the effectiveness of mitigation efforts, five telephone surveys between 1993 and 2001 were conducted by the Humboldt Earthquake Education Center. A sixth survey is planned for this fall. Each survey includes between 400 and 600 respondents. Over the nine year period covered by the surveys, the percent with houses secured to foundations has increased from 58 to 80 percent, respondents aware of a local tsunami hazard increased

  15. Foreshocks and aftershocks of the Great 1857 California earthquake

    USGS Publications Warehouse

    Meltzner, A.J.; Wald, D.J.

    1999-01-01

    The San Andreas fault is the longest fault in California and one of the longest strike-slip faults anywhere in the world, yet we know little about many aspects of its behavior before, during, and after large earthquakes. We conducted a study to locate and to estimate magnitudes for the largest foreshocks and aftershocks of the 1857 M 7.9 Fort Tejon earthquake on the central and southern segments of the fault. We began by searching archived first-hand accounts from 1857 through 1862, by grouping felt reports temporally, and by assigning modified Mercalli intensities to each site. We then used a modified form of the grid-search algorithm of Bakum and Wentworth, derived from empirical analysis of modern earthquakes, to find the location and magnitude most consistent with the assigned intensities for each of the largest events. The result confirms a conclusion of Sieh that at least two foreshocks ('dawn' and 'sunrise') located on or near the Parkfield segment of the San Andreas fault preceded the mainshock. We estimate their magnitudes to be M ~ 6.1 and M ~ 5.6, respectively. The aftershock rate was below average but within one standard deviation of the number of aftershocks expected based on statistics of modern southern California mainshock-aftershock sequences. The aftershocks included two significant events during the first eight days of the sequence, with magnitudes M ~ 6.25 and M ~ 6.7, near the southern half of the rupture; later aftershocks included a M ~ 6 event near San Bernardino in December 1858 and a M ~ 6.3 event near the Parkfield segment in April 1860. From earthquake logs at Fort Tejon, we conclude that the aftershock sequence lasted a minimum of 3.75 years.

  16. Using SLAM to Look For the Dog Valley Fault, Truckee Area, California

    NASA Astrophysics Data System (ADS)

    Cronin, V. S.; Ashburn, J. A.; Sverdrup, K. A.

    2014-12-01

    The Truckee earthquake (9/12/1966, ML6.0) was a left-lateral event on a previously unrecognized NW-trending fault. The Prosser Creek and Boca Dams sustained damage, and the trace of the suspected causative fault passes near or through the site of the then-incomplete Stampede Dam. Another M6 earthquake occurred along the same general trend in 1948 with an epicenter in Dog Valley ~14 km to the NW of the 1966 epicenter. This trend is called the Dog Valley Fault (DVF), and its location on the ground surface is suggested by a prominent but broad zone of geomorphic lineaments near the cloud of aftershock epicenters determined for the 1966 event. Various ground effects of the 1966 event described by Kachadoorian et al. (1967) were located within this broad zone. The upper shoreface of reservoirs in the Truckee-Prosser-Martis basin are now exposed due to persistent drought. We have examined fault strands in a roadcut and exposed upper shoreface adjacent to the NE abutment of Stampede Dam. These are interpreted to be small-displacement splays associated with the DVF -- perhaps elements of the DVF damage zone. We have used the Seismo-Lineament Analysis Method (SLAM) to help us constrain the location of the DVF, based on earthquake focal mechanisms. Seismo-lineaments were computed, using recent revisions in the SLAM code (bearspace.baylor.edu/Vince_Cronin/www/SLAM/), for the 1966 main earthquake and for the better-recorded earthquakes of 7/3/1983 (M4) and 8/30/1992 (M3.2) that are inferred to have occurred along the DVF. Associated geomorphic analysis and some field reconnaissance identified a trend that might be associated with a fault, extending from the NW end of Prosser Creek Reservoir ~32° toward the Stampede Dam area. Triangle-strain analysis using horizontal velocities of local Plate Boundary Observatory GPS sites P146, P149, P150 and SLID indicates that the area rotates clockwise ~1-2°/Myr relative to the stable craton, as might be expected because the study area is

  17. Groundwater quality in the western San Joaquin Valley, California

    USGS Publications Warehouse

    Fram, Miranda S.

    2017-06-09

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. The Western San Joaquin Valley is one of the study units being evaluated. 

  18. 76 FR 69135 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-08

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of the... of Subjects in 40 CFR Part 52 Environmental protection, Air pollution control, Incorporation by...

  19. 77 FR 64427 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-22

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of the..., Gas, and Geothermal Resources confirmed that in the Ventura County Air Pollution Control District...

  20. 76 FR 16696 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-25

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVAPCD) portion of the...)(2)). List of Subjects in 40 CFR Part 52 Environmental protection, Air pollution control...

  1. 75 FR 24408 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-05

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVAPCD) portion of the...)(2)). List of Subjects in 40 CFR Part 52 Environmental protection, Air pollution control...

  2. 75 FR 1715 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-13

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVAPCD) portion of the...)(2)). List of Subjects in 40 CFR Part 52 Environmental protection, Air pollution control...

  3. 76 FR 68106 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-03

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of the...)(2)). List of Subjects in 40 CFR Part 52 Environmental protection, Air pollution control...

  4. 76 FR 45212 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-28

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... proposing to approve San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) Rule 3170... (CAA or Act). EPA is also proposing to approve SJVUAPCD's fee-equivalent program, which includes Rule...

  5. Injuries and Traumatic Psychological Exposures Associated with the South Napa Earthquake - California, 2014.

    PubMed

    Attfield, Kathleen R; Dobson, Christine B; Henn, Jennifer B; Acosta, Meileen; Smorodinsky, Svetlana; Wilken, Jason A; Barreau, Tracy; Schreiber, Merritt; Windham, Gayle C; Materna, Barbara L; Roisman, Rachel

    2015-09-11

    On August 24, 2014, at 3:20 a.m., a magnitude 6.0 earthquake struck California, with its epicenter in Napa County (1). The earthquake was the largest to affect the San Francisco Bay area in 25 years and caused significant damage in Napa and Solano counties, including widespread power outages, five residential fires, and damage to roadways, waterlines, and 1,600 buildings (2). Two deaths resulted (2). On August 25, Napa County Public Health asked the California Department of Public Health (CDPH) for assistance in assessing postdisaster health effects, including earthquake-related injuries and effects on mental health. On September 23, Solano County Public Health requested similar assistance. A household-level Community Assessment for Public Health Emergency Response (CASPER) was conducted for these counties in two cities (Napa, 3 weeks after the earthquake, and Vallejo, 6 weeks after the earthquake). Among households reporting injuries, a substantial proportion (48% in Napa and 37% in western Vallejo) reported that the injuries occurred during the cleanup period, suggesting that increased messaging on safety precautions after a disaster might be needed. One fifth of respondents overall (27% in Napa and 9% in western Vallejo) reported one or more traumatic psychological exposures in their households. These findings were used by Napa County Mental Health to guide immediate-term mental health resource allocations and to conduct public training sessions and education campaigns to support persons with mental health risks following the earthquake. In addition, to promote community resilience and future earthquake preparedness, Napa County Public Health subsequently conducted community events on the earthquake anniversary and provided outreach workers with psychological first aid training.

  6. Structural and lithologic study of Northern Coast Range and Sacramento Valley, California

    NASA Technical Reports Server (NTRS)

    Rich, E. I. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Preliminary analysis of the data received has disclosed two potentially important northwest-trending systems of linear features within the Northern California Coast Ranges. A third system, which trends northeast, can be traced with great uncertainty across the alluviated part of the Sacramento Valley and into the foothills of the Sierra Nevada. These linear features may represent fault systems or zones of shearing. Of interest, although not yet verified, is the observation that some of the mercury concentrations and some of the geothermally active areas of California may be located at the intersection of the Central and the Valley Systems. One, perhaps two, stratigraphic unconformities within the Late Mesozoic sedimentary rocks were detected during preliminary examination of the imagery; however, more analysis is necessary in order to verify this preliminary interpretation. A heretofore unrecognized, large circular depression, about 15 km in diameter, was detected within the alluviated part of the Sacramento Valley. The depression is adjacent to a large laccolithic intrusion and may be geologically related to it. Changes in the photogeologic characteristics of this feature will continue to be monitored.

  7. The 2010 M w 7.2 El Mayor-Cucapah Earthquake Sequence, Baja California, Mexico and Southernmost California, USA: Active Seismotectonics along the Mexican Pacific Margin

    NASA Astrophysics Data System (ADS)

    Hauksson, Egill; Stock, Joann; Hutton, Kate; Yang, Wenzheng; Vidal-Villegas, J. Antonio; Kanamori, Hiroo

    2011-08-01

    The El Mayor-Cucapah earthquake sequence started with a few foreshocks in March 2010, and a second sequence of 15 foreshocks of M > 2 (up to M4.4) that occurred during the 24 h preceding the mainshock. The foreshocks occurred along a north-south trend near the mainshock epicenter. The M w 7.2 mainshock on April 4 exhibited complex faulting, possibly starting with a ~M6 normal faulting event, followed ~15 s later by the main event, which included simultaneous normal and right-lateral strike-slip faulting. The aftershock zone extends for 120 km from the south end of the Elsinore fault zone north of the US-Mexico border almost to the northern tip of the Gulf of California. The waveform-relocated aftershocks form two abutting clusters, each about 50 km long, as well as a 10 km north-south aftershock zone just north of the epicenter of the mainshock. Even though the Baja California data are included, the magnitude of completeness and the hypocentral errors increase gradually with distance south of the international border. The spatial distribution of large aftershocks is asymmetric with five M5+ aftershocks located to the south of the mainshock, and only one M5.7 aftershock, but numerous smaller aftershocks to the north. Further, the northwest aftershock cluster exhibits complex faulting on both northwest and northeast planes. Thus, the aftershocks also express a complex pattern of stress release along strike. The overall rate of decay of the aftershocks is similar to the rate of decay of a generic California aftershock sequence. In addition, some triggered seismicity was recorded along the Elsinore and San Jacinto faults to the north, but significant northward migration of aftershocks has not occurred. The synthesis of the El Mayor-Cucapah sequence reveals transtensional regional tectonics, including the westward growth of the Mexicali Valley and the transfer of Pacific-North America plate motion from the Gulf of California in the south into the southernmost San

  8. Development of a State-Wide 3-D Seismic Tomography Velocity Model for California

    NASA Astrophysics Data System (ADS)

    Thurber, C. H.; Lin, G.; Zhang, H.; Hauksson, E.; Shearer, P.; Waldhauser, F.; Hardebeck, J.; Brocher, T.

    2007-12-01

    We report on progress towards the development of a state-wide tomographic model of the P-wave velocity for the crust and uppermost mantle of California. The dataset combines first arrival times from earthquakes and quarry blasts recorded on regional network stations and travel times of first arrivals from explosions and airguns recorded on profile receivers and network stations. The principal active-source datasets are Geysers-San Pablo Bay, Imperial Valley, Livermore, W. Mojave, Gilroy-Coyote Lake, Shasta region, Great Valley, Morro Bay, Mono Craters-Long Valley, PACE, S. Sierras, LARSE 1 and 2, Loma Prieta, BASIX, San Francisco Peninsula and Parkfield. Our beta-version model is coarse (uniform 30 km horizontal and variable vertical gridding) but is able to image the principal features in previous separate regional models for northern and southern California, such as the high-velocity subducting Gorda Plate, upper to middle crustal velocity highs beneath the Sierra Nevada and much of the Coast Ranges, the deep low-velocity basins of the Great Valley, Ventura, and Los Angeles, and a high- velocity body in the lower crust underlying the Great Valley. The new state-wide model has improved areal coverage compared to the previous models, and extends to greater depth due to the data at large epicentral distances. We plan a series of steps to improve the model. We are enlarging and calibrating the active-source dataset as we obtain additional picks from investigators and perform quality control analyses on the existing and new picks. We will also be adding data from more quarry blasts, mainly in northern California, following an identification and calibration procedure similar to Lin et al. (2006). Composite event construction (Lin et al., in press) will be carried out for northern California for use in conventional tomography. A major contribution of the state-wide model is the identification of earthquakes yielding arrival times at both the Northern California Seismic

  9. Depth dependence of earthquake frequency-magnitude distributions in California: Implications for rupture initiation

    USGS Publications Warehouse

    Mori, J.; Abercrombie, R.E.

    1997-01-01

    Statistics of earthquakes in California show linear frequency-magnitude relationships in the range of M2.0 to M5.5 for various data sets. Assuming Gutenberg-Richter distributions, there is a systematic decrease in b value with increasing depth of earthquakes. We find consistent results for various data sets from northern and southern California that both include and exclude the larger aftershock sequences. We suggest that at shallow depth (???0 to 6 km) conditions with more heterogeneous material properties and lower lithospheric stress prevail. Rupture initiations are more likely to stop before growing into large earthquakes, producing relatively more smaller earthquakes and consequently higher b values. These ideas help to explain the depth-dependent observations of foreshocks in the western United States. The higher occurrence rate of foreshocks preceding shallow earthquakes can be interpreted in terms of rupture initiations that are stopped before growing into the mainshock. At greater depth (9-15 km), any rupture initiation is more likely to continue growing into a larger event, so there are fewer foreshocks. If one assumes that frequency-magnitude statistics can be used to estimate probabilities of a small rupture initiation growing into a larger earthquake, then a small (M2) rupture initiation at 9 to 12 km depth is 18 times more likely to grow into a M5.5 or larger event, compared to the same small rupture initiation at 0 to 3 km. Copyright 1997 by the American Geophysical Union.

  10. Source properties of earthquakes near the Salton Sea triggered by the 16 October 1999 M 7.1 Hector Mine, California, earthquake

    USGS Publications Warehouse

    Hough, S.E.; Kanamori, H.

    2002-01-01

    We analyze the source properties of a sequence of triggered earthquakes that occurred near the Salton Sea in southern California in the immediate aftermath of the M 7.1 Hector Mine earthquake of 16 October 1999. The sequence produced a number of early events that were not initially located by the regional network, including two moderate earthquakes: the first within 30 sec of the P-wave arrival and a second approximately 10 minutes after the mainshock. We use available amplitude and waveform data from these events to estimate magnitudes to be approximately 4.7 and 4.4, respectively, and to obtain crude estimates of their locations. The sequence of small events following the initial M 4.7 earthquake is clustered and suggestive of a local aftershock sequence. Using both broadband TriNet data and analog data from the Southern California Seismic Network (SCSN), we also investigate the spectral characteristics of the M 4.4 event and other triggered earthquakes using empirical Green's function (EGF) analysis. We find that the source spectra of the events are consistent with expectations for tectonic (brittle shear failure) earthquakes, and infer stress drop values of 0.1 to 6 MPa for six M 2.1 to M 4.4 events. The estimated stress drop values are within the range observed for tectonic earthquakes elsewhere. They are relatively low compared to typically observed stress drop values, which is consistent with expectations for faulting in an extensional, high heat flow regime. The results therefore suggest that, at least in this case, triggered earthquakes are associated with a brittle shear failure mechanism. This further suggests that triggered earthquakes may tend to occur in geothermal-volcanic regions because shear failure occurs at, and can be triggered by, relatively low stresses in extensional regimes.

  11. 76 FR 56134 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-12

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... approve revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of... preempt Tribal law. List of Subjects in 40 CFR Part 52 Environmental protection, Air pollution control...

  12. 76 FR 53640 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-29

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of the... section 307(b)(2)). List of Subjects in 40 CFR Part 52 Environmental protection, Air pollution control...

  13. 76 FR 56132 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-12

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... approve revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of... preempt Tribal law. List of Subjects in 40 CFR Part 52 Environmental protection, Air pollution control...

  14. 75 FR 57862 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-23

    ... the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District... revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of the... section 307(b)(2)). List of Subjects in 40 CFR Part 52 Environmental protection, Air pollution control...

  15. Lateral spread hazard mapping of the northern Salt Lake Valley, Utah, for a M7.0 scenario earthquake

    USGS Publications Warehouse

    Olsen, M.J.; Bartlett, S.F.; Solomon, B.J.

    2007-01-01

    This paper describes the methodology used to develop a lateral spread-displacement hazard map for northern Salt Lake Valley, Utah, using a scenario M7.0 earthquake occurring on the Salt Lake City segment of the Wasatch fault. The mapping effort is supported by a substantial amount of geotechnical, geologic, and topographic data compiled for the Salt Lake Valley, Utah. ArcGIS?? routines created for the mapping project then input this information to perform site-specific lateral spread analyses using methods developed by Bartlett and Youd (1992) and Youd et al. (2002) at individual borehole locations. The distributions of predicted lateral spread displacements from the boreholes located spatially within a geologic unit were subsequently used to map the hazard for that particular unit. The mapped displacement zones consist of low hazard (0-0.1 m), moderate hazard (0.1-0.3 m), high hazard (0.3-1.0 m), and very high hazard (> 1.0 m). As expected, the produced map shows the highest hazard in the alluvial deposits at the center of the valley and in sandy deposits close to the fault. This mapping effort is currently being applied to the southern part of the Salt Lake Valley, Utah, and probabilistic maps are being developed for the entire valley. ?? 2007, Earthquake Engineering Research Institute.

  16. Kirschenmann Road multi-well monitoring site, Cuyama Valley, Santa Barbara County, California

    USGS Publications Warehouse

    Everett, R.R.; Hanson, R.T.; Sweetkind, D.S.

    2011-01-01

    The U.S. Geological Survey (USGS), in cooperation with the Water Agency Division of the Santa Barbara County Department of Public Works, is evaluating the geohydrology and water availability of the Cuyama Valley, California (fig. 1). As part of this evaluation, the USGS installed the Cuyama Valley Kirschenmann Road multiple-well monitoring site (CVKR) in the South-Main subregion of the Cuyama Valley (fig. 1). The CVKR well site is designed to allow for the collection of depth-specific water-level and water-quality data. Data collected at this site provides information about the geology, hydrology, geophysics, and geochemistry of the local aquifer system, thus, enhancing the understanding of the geohydrologic framework of the Cuyama Valley. This report presents the construction information and initial geohydrologic data collected from the CVKR monitoring site, along with a brief comparison to selected supply and irrigation wells from the major subregions of the Cuyama Valley (fig. 1).

  17. Earthquake Rate Model 2.2 of the 2007 Working Group for California Earthquake Probabilities, Appendix D: Magnitude-Area Relationships

    USGS Publications Warehouse

    Stein, Ross S.

    2007-01-01

    Summary To estimate the down-dip coseismic fault dimension, W, the Executive Committee has chosen the Nazareth and Hauksson (2004) method, which uses the 99% depth of background seismicity to assign W. For the predicted earthquake magnitude-fault area scaling used to estimate the maximum magnitude of an earthquake rupture from a fault's length, L, and W, the Committee has assigned equal weight to the Ellsworth B (Working Group on California Earthquake Probabilities, 2003) and Hanks and Bakun (2002) (as updated in 2007) equations. The former uses a single relation; the latter uses a bilinear relation which changes slope at M=6.65 (A=537 km2).

  18. Statiscal analysis of an earthquake-induced landslide distribution - The 1989 Loma Prieta, California event

    USGS Publications Warehouse

    Keefer, D.K.

    2000-01-01

    The 1989 Loma Prieta, California earthquake (moment magnitude, M=6.9) generated landslides throughout an area of about 15,000 km2 in central California. Most of these landslides occurred in an area of about 2000 km2 in the mountainous terrain around the epicenter, where they were mapped during field investigations immediately following the earthquake. The distribution of these landslides is investigated statistically, using regression and one-way analysisof variance (ANOVA) techniques to determine how the occurrence of landslides correlates with distance from the earthquake source, slope steepness, and rock type. The landslide concentration (defined as the number of landslide sources per unit area) has a strong inverse correlation with distance from the earthquake source and a strong positive correlation with slope steepness. The landslide concentration differs substantially among the various geologic units in the area. The differences correlate to some degree with differences in lithology and degree of induration, but this correlation is less clear, suggesting a more complex relationship between landslide occurrence and rock properties. ?? 2000 Elsevier Science B.V. All rights reserved.

  19. Dilational processes accompanying earthquakes in the Long Valley Caldera

    USGS Publications Warehouse

    Dreger, Douglas S.; Tkalcic, Hrvoje; Johnston, M.

    2000-01-01

    Regional distance seismic moment tensor determinations and broadband waveforms of moment magnitude 4.6 to 4.9 earthquakes from a November 1997 Long Valley Caldera swarm, during an inflation episode, display evidence of anomalous seismic radiation characterized by non-double couple (NDC) moment tensors with significant volumetric components. Observed coseismic dilation suggests that hydrothermal or magmatic processes are directly triggering some of the seismicity in the region. Similarity in the NDC solutions implies a common source process, and the anomalous events may have been triggered by net fault-normal stress reduction due to high-pressure fluid injection or pressurization of fluid-saturated faults due to magmatic heating.

  20. 3-D View of Death Valley, California

    NASA Image and Video Library

    2001-07-21

    This 3-D perspective view looking north over Death Valley, California, was produced by draping ASTER nighttime thermal infrared data over topographic data from the US Geological Survey. The ASTER data were acquired April 7, 2000 with the multi-spectral thermal infrared channels, and cover an area of 60 by 80 km (37 by 50 miles). Bands 13, 12, and 10 are displayed in red, green and blue respectively. The data have been computer enhanced to exaggerate the color variations that highlight differences in types of surface materials. Salt deposits on the floor of Death Valley appear in shades of yellow, green, purple, and pink, indicating presence of carbonate, sulfate, and chloride minerals. The Panamint Mtns. to the west, and the Black Mtns. to the east, are made up of sedimentary limestones, sandstones, shales, and metamorphic rocks. The bright red areas are dominated by the mineral quartz, such as is found in sandstones; green areas are limestones. In the lower center part of the image is Badwater, the lowest point in North America. http://photojournal.jpl.nasa.gov/catalog/PIA02663

  1. A Comparison of Groundwater Storage Using GRACE Data, Groundwater Levels, and a Hydrological Model in Californias Central Valley

    NASA Technical Reports Server (NTRS)

    Kuss, Amber; Brandt, William; Randall, Joshua; Floyd, Bridget; Bourai, Abdelwahab; Newcomer, Michelle; Skiles, Joseph; Schmidt, Cindy

    2011-01-01

    The Gravity Recovery and Climate Experiment (GRACE) measures changes in total water storage (TWS) remotely, and may provide additional insight to the use of well-based data in California's agriculturally productive Central Valley region. Under current California law, well owners are not required to report groundwater extraction rates, making estimation of total groundwater extraction difficult. As a result, other groundwater change detection techniques may prove useful. From October 2002 to September 2009, GRACE was used to map changes in TWS for the three hydrological regions (the Sacramento River Basin, the San Joaquin River Basin, and the Tulare Lake Basin) encompassing the Central Valley aquifer. Net groundwater storage changes were calculated from the changes in TWS for each of the three hydrological regions and by incorporating estimates for additional components of the hydrological budget including precipitation, evapotranspiration, soil moisture, snow pack, and surface water storage. The calculated changes in groundwater storage were then compared to simulated values from the California Department of Water Resource's Central Valley Groundwater- Surface Water Simulation Model (C2VSIM) and their Water Data Library (WDL) Geographic Information System (GIS) change in storage tool. The results from the three methods were compared. Downscaling GRACE data into the 21 smaller Central Valley sub-regions included in C2VSIM was also evaluated. This work has the potential to improve California's groundwater resource management and use of existing hydrological models for the Central Valley.

  2. Holocene slip rates along the San Andreas Fault System in the San Gorgonio Pass and implications for large earthquakes in southern California

    NASA Astrophysics Data System (ADS)

    Heermance, Richard V.; Yule, Doug

    2017-06-01

    The San Gorgonio Pass (SGP) in southern California contains a 40 km long region of structural complexity where the San Andreas Fault (SAF) bifurcates into a series of oblique-slip faults with unknown slip history. We combine new 10Be exposure ages (Qt4: 8600 (+2100, -2200) and Qt3: 5700 (+1400, -1900) years B.P.) and a radiocarbon age (1260 ± 60 years B.P.) from late Holocene terraces with scarp displacement of these surfaces to document a Holocene slip rate of 5.7 (+2.7, -1.5) mm/yr combined across two faults. Our preferred slip rate is 37-49% of the average slip rates along the SAF outside the SGP (i.e., Coachella Valley and San Bernardino sections) and implies that strain is transferred off the SAF in this area. Earthquakes here most likely occur in very large, throughgoing SAF events at a lower recurrence than elsewhere on the SAF, so that only approximately one third of SAF ruptures penetrate or originate in the pass.Plain Language SummaryHow large are <span class="hlt">earthquakes</span> on the southern San Andreas Fault? The answer to this question depends on whether or not the <span class="hlt">earthquake</span> is contained only along individual fault sections, such as the Coachella <span class="hlt">Valley</span> section north of Palm Springs, or the rupture crosses multiple sections including the area through the San Gorgonio Pass. We have determined the age and offset of faulted stream deposits within the San Gorgonio Pass to document slip rates of these faults over the last 10,000 years. Our results indicate a long-term slip rate of 6 mm/yr, which is almost 1/2 of the rates east and west of this area. These new rates, combined with faulted geomorphic surfaces, imply that large magnitude <span class="hlt">earthquakes</span> must occasionally rupture a 300 km length of the San Andreas Fault from the Salton Sea to the Mojave Desert. Although many ( 65%) <span class="hlt">earthquakes</span> along the southern San Andreas Fault likely do not rupture through the pass, our new results suggest that large >Mw 7.5 <span class="hlt">earthquakes</span> are possible</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://archives.datapages.com/data/pacific/data/036/036001/1_ps0360001.htm','USGSPUBS'); return false;" href="http://archives.datapages.com/data/pacific/data/036/036001/1_ps0360001.htm"><span>Geological literature on the San Joaquin <span class="hlt">Valley</span> of <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Maher, J.C.; Trollman, W.M.; Denman, J.M.</p> <p>1973-01-01</p> <p>The following list of references includes most of the geological literature on the San Joaquin <span class="hlt">Valley</span> and vicinity in central <span class="hlt">California</span> (see figure 1) published prior to January 1, 1973. The San Joaquin <span class="hlt">Valley</span> comprises all or parts of 11 counties -- Alameda, Calaveras, Contra Costa, Fresno, Kern, Kings, Madera, Merced, San Joaquin, Stanislaus, and Tulare (figure 2). As a matter of convenient geographical classification the boundaries of the report area have been drawn along county lines, and to include San Benito and Santa Clara Counties on the west and Mariposa and Tuolumne Counties on the east. Therefore, this list of geological literature includes some publications on the Diablo and Temblor Ranges on the west, the Tehachapi Mountains and Mojave Desert on the south, and the Sierra Nevada Foothills and Mountains on the east.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70162360','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70162360"><span>One hundred years of <span class="hlt">earthquake</span> recording at the University of <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bolt, B. A.</p> <p>1987-01-01</p> <p>The best seismographs then available arrived from England in 1887 and were installed at Lick Observatory on Mt.Hamilton and at the Students Astronomical Observatory on the Berkeley campus. The first <span class="hlt">California</span> <span class="hlt">earthquake</span> recorded by the Lick instrument was on April 24, 1887. These seismographic stations have functioned continuously from their founding to the present day, with improvements in instruments from time to time as technology advanced. Now they are part of a sesimogrpahic network of 16 stations recording with great completeness both local and distant <span class="hlt">earthquakes</span>. </p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA13027.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA13027.html"><span>NASA Satellite Imagery Shows Sparse Population of Region Near Baja, <span class="hlt">California</span> <span class="hlt">Earthquake</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2010-04-09</p> <p>This image from NASA Terra spacecraft shows where a magnitude 7.2 <span class="hlt">earthquake</span> struck in Mexico Baja, <span class="hlt">California</span> at shallow depth along the principal plate boundary between the North American and Pacific plates on April 4, 2010.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70156901','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70156901"><span>On the reported ionospheric precursor of the 1999 Hector Mine, <span class="hlt">California</span> <span class="hlt">earthquake</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Thomas, Jeremy N.; Love, Jeffrey J.; Komjathy, Attila; Verkhoglyadova, Olga P.; Butala, Mark; Rivera, Nicholas</p> <p>2012-01-01</p> <p>Using Global Positioning System (GPS) data from sites near the 16 Oct. 1999 Hector Mine, <span class="hlt">California</span> <span class="hlt">earthquake</span>, Pulinets et al. (2007) identified anomalous changes in the ionospheric total electron content (TEC) starting one week prior to the <span class="hlt">earthquake</span>. Pulinets (2007) suggested that precursory phenomena of this type could be useful for predicting <span class="hlt">earthquakes</span>. On the other hand, and in a separate analysis, Afraimovich et al. (2004) concluded that TEC variations near the epicenter were controlled by solar and geomagnetic activity that were unrelated to the <span class="hlt">earthquake</span>. In an investigation of these very different results, we examine TEC time series of long duration from GPS stations near and far from the epicenter of the Hector Mine <span class="hlt">earthquake</span>, and long before and long after the <span class="hlt">earthquake</span>. While we can reproduce the essential time series results of Pulinets et al., we find that the signal they identify as anomalous is not actually anomalous. Instead, it is just part of normal global-scale TEC variation. We conclude that the TEC anomaly reported by Pulinets et al. is unrelated to the Hector Mine <span class="hlt">earthquake</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EP%26S...68...10T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EP%26S...68...10T"><span>Strong ground motion in the Kathmandu <span class="hlt">Valley</span> during the 2015 Gorkha, Nepal, <span class="hlt">earthquake</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Takai, Nobuo; Shigefuji, Michiko; Rajaure, Sudhir; Bijukchhen, Subeg; Ichiyanagi, Masayoshi; Dhital, Megh Raj; Sasatani, Tsutomu</p> <p>2016-01-01</p> <p>On 25 April 2015, a large <span class="hlt">earthquake</span> of Mw 7.8 occurred along the Main Himalayan Thrust fault in central Nepal. It was caused by a collision of the Indian Plate beneath the Eurasian Plate. The epicenter was near the Gorkha region, 80 km northwest of Kathmandu, and the rupture propagated toward east from the epicentral region passing through the sediment-filled Kathmandu <span class="hlt">Valley</span>. This event resulted in over 8000 fatalities, mostly in Kathmandu and the adjacent districts. We succeeded in observing strong ground motions at our four observation sites (one rock site and three sedimentary sites) in the Kathmandu <span class="hlt">Valley</span> during this devastating <span class="hlt">earthquake</span>. While the observed peak ground acceleration values were smaller than the predicted ones that were derived from the use of a ground motion prediction equation, the observed peak ground velocity values were slightly larger than the predicted ones. The ground velocities observed at the rock site (KTP) showed a simple velocity pulse, resulting in monotonic-step displacements associated with the permanent tectonic offset. The vertical ground velocities observed at the sedimentary sites had the same pulse motions that were observed at the rock site. In contrast, the horizontal ground velocities as well as accelerations observed at three sedimentary sites showed long duration with conspicuous long-period oscillations, due to the <span class="hlt">valley</span> response. The horizontal <span class="hlt">valley</span> response was characterized by large amplification (about 10) and prolonged oscillations. However, the predominant period and envelope shape of their oscillations differed from site to site, indicating a complicated basin structure. Finally, on the basis of the velocity response spectra, we show that the horizontal long-period oscillations on the sedimentary sites had enough destructive power to damage high-rise buildings with natural periods of 3 to 5 s.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/pp/1794/a/chapters/pp1794a_chapter17.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/pp/1794/a/chapters/pp1794a_chapter17.pdf"><span>Central <span class="hlt">California</span> <span class="hlt">Valley</span> Ecoregion: Chapter 17 in Status and trends of land change in the Western United States--1973 to 2000</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sleeter, Benjamin M.</p> <p>2012-01-01</p> <p>The Central <span class="hlt">California</span> <span class="hlt">Valley</span> Ecoregion, which covers approximately 45,983 km2 (17,754 mi2), is an elongated basin extending approximately 650 km north to south through central <span class="hlt">California</span> (fig. 1) (Omernik, 1987; U.S. Environmental Protection Agency, 1997). The ecoregion is surrounded entirely by the Southern and Central <span class="hlt">California</span> Chaparral and Oak Woodlands Ecoregion, which includes parts of the Coast Ranges to the west and which is bounded by the Sierra Nevada to the east. The Central <span class="hlt">California</span> <span class="hlt">Valley</span> Ecoregion accounts for more than half of California’s agricultural production value and is one of the most important agricultural regions in the country, with flat terrain, fertile soils, a favorable climate, and nearly 70 percent of its land in cultivation (Kuminoff and others, 2000; Sumner and others, 2003). Commodities produced in the region include milk and dairy, cattle and calves, cotton, almonds, citrus, and grapes, among others (U.S. Department of Agriculture, 2004; Johnston and McCalla, 2004; Kuminoff and others, 2000) (figs. 2A,B,C). Six of the top eight agricultural-producing counties in <span class="hlt">California</span> are located at least partly within the Central <span class="hlt">California</span> <span class="hlt">Valley</span> Ecoregion (Kuminoff and others, 2000) (table 1). The Central <span class="hlt">California</span> <span class="hlt">Valley</span> Ecoregion is also home to nearly 5 million people spread throughout the region, including the major cities of Sacramento (state capital), Fresno, Bakersfield, and Stockton, <span class="hlt">California</span> (U.S. Census Bureau, 2000) (fig. 1).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2004/1269/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2004/1269/"><span>Liquefaction-induced lateral spreading in Oceano, <span class="hlt">California</span>, during the 2003 San Simeon <span class="hlt">Earthquake</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Holzer, Thomas L.; Noce, Thomas E.; Bennett, Michael J.; Di Alessandro, Carola; Boatwright, John; Tinsley, John C.; Sell, Russell W.; Rosenberg, Lewis I.</p> <p>2004-01-01</p> <p>The December 22, 2003, San Simeon, <span class="hlt">California</span>, (M6.5) <span class="hlt">earthquake</span> caused damage to houses, road surfaces, and underground utilities in Oceano, <span class="hlt">California</span>. The community of Oceano is approximately 50 miles (80 km) from the <span class="hlt">earthquake</span> epicenter. Damage at this distance from a M6.5 <span class="hlt">earthquake</span> is unusual. To understand the causes of this damage, the U.S. Geological Survey conducted extensive subsurface exploration and monitoring of aftershocks in the months after the <span class="hlt">earthquake</span>. The investigation included 37 seismic cone penetration tests, 5 soil borings, and aftershock monitoring from January 28 to March 7, 2004. The USGS investigation identified two <span class="hlt">earthquake</span> hazards in Oceano that explain the San Simeon <span class="hlt">earthquake</span> damage?site amplification and liquefaction. Site amplification is a phenomenon observed in many <span class="hlt">earthquakes</span> where the strength of the shaking increases abnormally in areas where the seismic-wave velocity of shallow geologic layers is low. As a result, <span class="hlt">earthquake</span> shaking is felt more strongly than in surrounding areas without similar geologic conditions. Site amplification in Oceano is indicated by the physical properties of the geologic layers beneath Oceano and was confirmed by monitoring aftershocks. Liquefaction, which is also commonly observed during <span class="hlt">earthquakes</span>, is a phenomenon where saturated sands lose their strength during an <span class="hlt">earthquake</span> and become fluid-like and mobile. As a result, the ground may undergo large permanent displacements that can damage underground utilities and well-built surface structures. The type of displacement of major concern associated with liquefaction is lateral spreading because it involves displacement of large blocks of ground down gentle slopes or towards stream channels. The USGS investigation indicates that the shallow geologic units beneath Oceano are very susceptible to liquefaction. They include young sand dunes and clean sandy artificial fill that was used to bury and convert marshes into developable lots. Most of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.G41C..04L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.G41C..04L"><span>Groundwater withdrawal in the Central <span class="hlt">Valley</span>, <span class="hlt">California</span>: implications for San Andreas Fault stressing and lithosphere rheology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lundgren, P.; Liu, Z.; Ali, S. T.; Farr, T.; Faunt, C. C.</p> <p>2016-12-01</p> <p> <span class="hlt">earthquake</span> hazard on the nearby faults. Reference: Famiglietti, J. S., M. Lo, S. L. Ho, J. Bethune, K. J. Anderson, T. H. Syed, S. C. Swenson, C. R. de Linage, and M. Rodell, 2011, Satellites measure recent rates of groundwater depletion in <span class="hlt">California</span>'s Central <span class="hlt">Valley</span>, Geophys. Res. Lett., 38, L03403, doi:10.1029/2010GL046442.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/pp/pp1550/pp1550b/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/pp/pp1550/pp1550b/"><span>Chapter B. The Loma Prieta, <span class="hlt">California</span>, <span class="hlt">Earthquake</span> of October 17, 1989 - Forecasts</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Harris, Ruth A.</p> <p>1998-01-01</p> <p>The magnitude (Mw) 6.9 Loma Prieta <span class="hlt">earthquake</span> struck the San Francisco Bay region of central <span class="hlt">California</span> at 5:04 p.m. P.d.t. on October 17, 1989, killing 62 people and generating billions of dollars in property damage. Scientists were not surprised by the occurrence of a destructive <span class="hlt">earthquake</span> in this region and had, in fact, been attempting to forecast the location of the next large <span class="hlt">earthquake</span> in the San Francisco Bay region for decades. This paper summarizes more than 20 scientifically based forecasts made before the 1989 Loma Prieta <span class="hlt">earthquake</span> for a large <span class="hlt">earthquake</span> that might occur in the Loma Prieta area. The forecasts geographically closest to the actual <span class="hlt">earthquake</span> primarily consisted of right-lateral strike-slip motion on the San Andreas Fault northwest of San Juan Bautista. Several of the forecasts did encompass the magnitude of the actual <span class="hlt">earthquake</span>, and at least one approximately encompassed the along-strike rupture length. The 1989 Loma Prieta <span class="hlt">earthquake</span> differed from most of the forecasted events in two ways: (1) it occurred with considerable dip-slip in addition to strike-slip motion, and (2) it was much deeper than expected.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70042554','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70042554"><span>Rupture directivity of moderate <span class="hlt">earthquakes</span> in northern <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Seekins, Linda C.; Boatwright, John</p> <p>2010-01-01</p> <p>We invert peak ground velocity and acceleration (PGV and PGA) to estimate rupture direction and rupture velocity for 47 moderate <span class="hlt">earthquakes</span> (3.5≥M≥5.4) in northern <span class="hlt">California</span>. We correct sets of PGAs and PGVs recorded at stations less than 55–125 km, depending on source depth, for site amplification and source–receiver distance, then fit the residual peak motions to the unilateral directivity function of Ben-Menahem (1961). We independently invert PGA and PGV. The rupture direction can be determined using as few as seven peak motions if the station distribution is sufficient. The rupture velocity is unstable, however, if there are no takeoff angles within 30° of the rupture direction. Rupture velocities are generally subsonic (0.5β–0.9β); for stability, we limit the rupture velocity at v=0.92β, the Rayleigh wave speed. For 73 of 94 inversions, the rupture direction clearly identifies one of the nodal planes as the fault plane. The 35 strike-slip <span class="hlt">earthquakes</span> have rupture directions that range from nearly horizontal (6 events) to directly updip (5 events); the other 24 rupture partly along strike and partly updip. Two strike-slip <span class="hlt">earthquakes</span> rupture updip in one inversion and downdip in the other. All but 1 of the 11 thrust <span class="hlt">earthquakes</span> rupture predominantly updip. We compare the rupture directions for 10 M≥4.0 <span class="hlt">earthquakes</span> to the relative location of the mainshock and the first two weeks of aftershocks. Spatial distributions of 8 of 10 aftershock sequences agree well with the rupture directivity calculated for the mainshock.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMNH14A..03M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMNH14A..03M"><span>Mapping Drought Impacts on Agricultural Production in <span class="hlt">California</span>'s Central <span class="hlt">Valley</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Melton, F. S.; Guzman, A.; Johnson, L.; Rosevelt, C.; Verdin, J. P.; Dwyer, J. L.; Mueller, R.; Zakzeski, A.; Thenkabail, P. S.; Wallace, C.; Jones, J.; Windell, S.; Urness, J.; Teaby, A.; Hamblin, D.; Post, K. M.; Nemani, R. R.</p> <p>2014-12-01</p> <p>The ongoing drought in <span class="hlt">California</span> has substantially reduced surface water supplies for millions of acres of irrigated farmland in <span class="hlt">California</span>'s Central <span class="hlt">Valley</span>. Rapid assessment of drought impacts on agricultural production can aid water managers in assessing mitigation options, and guide decision making with respect to requests for local water transfers, county drought disaster designations, and allocation of emergency funds to mitigate drought impacts. Satellite remote sensing offers an efficient way to provide quantitative assessments of drought impacts on agricultural production and increases in idle acreage associated with reductions in water supply. A key advantage of satellite-based assessments is that they can provide a measure of land fallowing that is consistent across both space and time. We describe an approach for monthly and seasonal mapping of uncultivated agricultural acreage developed as part of a joint effort by USGS, USDA, NASA, and the <span class="hlt">California</span> Department of Water Resources to provide timely assessments of land fallowing during drought events. This effort has used the Central <span class="hlt">Valley</span> of <span class="hlt">California</span> as a pilot region for development and testing of an operational approach. To provide quantitative measures of uncultivated agricultural acreage from satellite data early in the season, we developed a decision tree algorithm and applied it to timeseries of data from Landsat TM, ETM+, OLI, and MODIS. Our effort has been focused on development of indicators of drought impacts in the March - August timeframe based on measures of crop development patterns relative to a reference period with average or above average rainfall. To assess the accuracy of the algorithms, monthly ground validation surveys were conducted across 640 fields from March - September, 2014. We present the algorithm along with updated results from the accuracy assessment, and discuss potential applications to other regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750012763','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750012763"><span>Overview of Reclamation's geothermal program in Imperial <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fulcher, M. K.</p> <p>1974-01-01</p> <p>The Bureau of Reclamation is presently involved in a unique Geothermal Resource Development Program in Imperial <span class="hlt">Valley</span>, <span class="hlt">California</span>. The main purpose of the investigations is to determine the feasibility of providing a source of fresh water through desalting geothermal fluids stored in the aquifers underlying the <span class="hlt">valley</span>. Significant progress in this research and development stage to date includes extensive geophysical investigations and the drilling of five geothermal wells on the Mesa anomaly. Four of the wells are for production and monitoring the anomaly, and one will be used for reinjection of waste brines from the desalting units. Two desalting units, a multistage flash unit and a vertical tube evaporator unit, have been erected at the East Mesa test site. The units have been operated on shakedown and continuous runs and have produced substantial quantities of high-quality water.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2014/5129/pdf/sir2014-5129.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2014/5129/pdf/sir2014-5129.pdf"><span>Quantitative rock-fall hazard and risk assessment for Yosemite <span class="hlt">Valley</span>, Yosemite National Park, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Stock, Greg M.; Luco, Nicolas; Collins, Brian D.; Harp, Edwin L.; Reichenbach, Paola; Frankel, Kurt L.</p> <p>2014-01-01</p> <p>Rock falls are common in Yosemite <span class="hlt">Valley</span>, <span class="hlt">California</span>, posing substantial hazard and risk to the approximately four million annual visitors to Yosemite National Park. Rock falls in Yosemite <span class="hlt">Valley</span> over the past few decades have damaged structures and caused injuries within developed regions located on or adjacent to talus slopes highlighting the need for additional investigations into rock-fall hazard and risk. This assessment builds upon previous investigations of rock-fall hazard and risk in Yosemite <span class="hlt">Valley</span> and focuses on hazard and risk to structures posed by relatively frequent fragmental-type rock falls as large as approximately 100,000 (cubic meters) in volume.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhDT........58W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhDT........58W"><span>Maximum Magnitude and Probabilities of Induced <span class="hlt">Earthquakes</span> in <span class="hlt">California</span> Geothermal Fields: Applications for a Science-Based Decision Framework</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Weiser, Deborah Anne</p> <p></p> <p>Induced seismicity is occurring at increasing rates around the country. Brodsky and Lajoie (2013) and others have recognized anthropogenic quakes at a few geothermal fields in <span class="hlt">California</span>. I use three techniques to assess if there are induced <span class="hlt">earthquakes</span> in <span class="hlt">California</span> geothermal fields; there are three sites with clear induced seismicity: Brawley, The Geysers, and Salton Sea. Moderate to strong evidence is found at Casa Diablo, Coso, East Mesa, and Susanville. Little to no evidence is found for Heber and Wendel. I develop a set of tools to reduce or cope with the risk imposed by these <span class="hlt">earthquakes</span>, and also to address uncertainties through simulations. I test if an <span class="hlt">earthquake</span> catalog may be bounded by an upper magnitude limit. I address whether the <span class="hlt">earthquake</span> record during pumping time is consistent with the past <span class="hlt">earthquake</span> record, or if injection can explain all or some of the <span class="hlt">earthquakes</span>. I also present ways to assess the probability of future <span class="hlt">earthquake</span> occurrence based on past records. I summarize current legislation for eight states where induced <span class="hlt">earthquakes</span> are of concern. Unlike tectonic <span class="hlt">earthquakes</span>, the hazard from induced <span class="hlt">earthquakes</span> has the potential to be modified. I discuss direct and indirect mitigation practices. I present a framework with scientific and communication techniques for assessing uncertainty, ultimately allowing more informed decisions to be made.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.epa.gov/publicnotices/california-antelope-valley-air-quality-management-district-vocs-motor-vehicle-assembly','PESTICIDES'); return false;" href="https://www.epa.gov/publicnotices/california-antelope-valley-air-quality-management-district-vocs-motor-vehicle-assembly"><span><span class="hlt">California</span>; Antelope <span class="hlt">Valley</span> Air Quality Management District; VOCs from Motor Vehicle Assembly Coating Operations</span></a></p> <p><a target="_blank" href="http://www.epa.gov/pesticides/search.htm">EPA Pesticide Factsheets</a></p> <p></p> <p></p> <p>EPA is proposing to approve a revision to the Antelope <span class="hlt">Valley</span> Air Quality Management District portion of the <span class="hlt">California</span> SIP concerning emissions of volatile organic compounds (VOCs) from motor vehicle assembly coating operations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.U61A0006A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.U61A0006A"><span>Archiving and Distributing Seismic Data at the Southern <span class="hlt">California</span> <span class="hlt">Earthquake</span> Data Center (SCEDC)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Appel, V. L.</p> <p>2002-12-01</p> <p>The Southern <span class="hlt">California</span> <span class="hlt">Earthquake</span> Data Center (SCEDC) archives and provides public access to <span class="hlt">earthquake</span> parametric and waveform data gathered by the Southern <span class="hlt">California</span> Seismic Network and since January 1, 2001, the TriNet seismic network, southern <span class="hlt">California</span>'s <span class="hlt">earthquake</span> monitoring network. The parametric data in the archive includes <span class="hlt">earthquake</span> locations, magnitudes, moment-tensor solutions and phase picks. The SCEDC waveform archive prior to TriNet consists primarily of short-period, 100-samples-per-second waveforms from the SCSN. The addition of the TriNet array added continuous recordings of 155 broadband stations (20 samples per second or less), and triggered seismograms from 200 accelerometers and 200 short-period instruments. Since the Data Center and TriNet use the same Oracle database system, new <span class="hlt">earthquake</span> data are available to the seismological community in near real-time. Primary access to the database and waveforms is through the Seismogram Transfer Program (STP) interface. The interface enables users to search the database for <span class="hlt">earthquake</span> information, phase picks, and continuous and triggered waveform data. Output is available in SAC, miniSEED, and other formats. Both the raw counts format (V0) and the gain-corrected format (V1) of COSMOS (Consortium of Organizations for Strong-Motion Observation Systems) are now supported by STP. EQQuest is an interface to prepackaged waveform data sets for select <span class="hlt">earthquakes</span> in Southern <span class="hlt">California</span> stored at the SCEDC. Waveform data for large-magnitude events have been prepared and new data sets will be available for download in near real-time following major events. The parametric data from 1981 to present has been loaded into the Oracle 9.2.0.1 database system and the waveforms for that time period have been converted to mSEED format and are accessible through the STP interface. The DISC optical-disk system (the "jukebox") that currently serves as the mass-storage for the SCEDC is in the process of being replaced</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2018/3026/fs20183026.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2018/3026/fs20183026.pdf"><span>Groundwater quality in the shallow aquifers of the Monterey Bay, Salinas <span class="hlt">Valley</span>, and adjacent highland areas, Southern Coast Ranges, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Burton, Carmen</p> <p>2018-05-30</p> <p>The Monterey-Salinas Shallow Aquifer study unit covers approximately 7,820 square kilometers (km2) in Santa Cruz, Monterey, and San Luis Obispo Counties in the Central Coast Hydrologic Region of <span class="hlt">California</span>. The study unit was divided into four study areas—Santa Cruz, Pajaro <span class="hlt">Valley</span>, Salinas <span class="hlt">Valley</span>, and Highlands. More than 75 percent of the water used for drinking-water supply in the Central Coast Hydrologic Region of <span class="hlt">California</span> is groundwater, and there are more than 8,000 well driller’s logs for domestic wells (<span class="hlt">California</span> Department of Water Resources, 2013).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2018/3026/fs20183026_.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2018/3026/fs20183026_.pdf"><span>Groundwater Quality in the Shallow Aquifers of the Monterey Bay, Salinas <span class="hlt">Valley</span>, and Adjacent Highland Areas, Southern Coast Ranges, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Burton, Carmen</p> <p>2018-05-30</p> <p>The Monterey-Salinas Shallow Aquifer study unit covers approximately 7,820 square kilometers (km2) in Santa Cruz, Monterey, and San Luis Obispo Counties in the Central Coast Hydrologic Region of <span class="hlt">California</span>. The study unit was divided into four study areas—Santa Cruz, Pajaro <span class="hlt">Valley</span>, Salinas <span class="hlt">Valley</span>, and Highlands. More than 75 percent of the water used for drinking-water supply in the Central Coast Hydrologic Region of <span class="hlt">California</span> is groundwater, and there are more than 8,000 well driller’s logs for domestic wells (<span class="hlt">California</span> Department of Water Resources, 2013).</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015HydJ...23.1205M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015HydJ...23.1205M"><span>Hydro-economic analysis of groundwater pumping for irrigated agriculture in <span class="hlt">California</span>'s Central <span class="hlt">Valley</span>, USA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Medellín-Azuara, Josué; MacEwan, Duncan; Howitt, Richard E.; Koruakos, George; Dogrul, Emin C.; Brush, Charles F.; Kadir, Tariq N.; Harter, Thomas; Melton, Forrest; Lund, Jay R.</p> <p>2015-09-01</p> <p>As in many places, groundwater in <span class="hlt">California</span> (USA) is the major alternative water source for agriculture during drought, so groundwater's availability will drive some inevitable changes in the state's water management. Currently, agricultural, environmental, and urban uses compete for groundwater, resulting in substantial overdraft in dry years with lowering of water tables, which in turn increases pumping costs and reduces groundwater pumping capacity. In this study, SWAP (an economic model of agricultural production and water use in <span class="hlt">California</span>) and C2VISim (the <span class="hlt">California</span> Department of Water Resources groundwater model for <span class="hlt">California</span>'s Central <span class="hlt">Valley</span>) are connected. This paper examines the economic costs of pumping replacement groundwater during drought and the potential loss of pumping capacity as groundwater levels drop. A scenario of three additional drought years continuing from 2014 show lower water tables in <span class="hlt">California</span>'s Central <span class="hlt">Valley</span> and loss of pumping capacity. Places without access to groundwater and with uncertain surface-water deliveries during drought are the most economically vulnerable in terms of crop revenues, employment and household income. This is particularly true for Tulare Lake Basin, which relies heavily on water imported from the Sacramento-San Joaquin Delta. Remote-sensing estimates of idle agricultural land between 2012 and 2014 confirm this finding. Results also point to the potential of a portfolio approach for agriculture, in which crop mixing and conservation practices have substantial roles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H52E..01F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H52E..01F"><span>Subsidence in the Central <span class="hlt">Valley</span>, <span class="hlt">California</span> 2007 - present measured by InSAR</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Farr, T. G.; Liu, Z.; Jones, C. E.</p> <p>2015-12-01</p> <p>Subsidence caused by groundwater pumping in the rich agricultural area of <span class="hlt">California</span>'s Central <span class="hlt">Valley</span> has been a problem for decades. Over the last few years, interferometric synthetic aperture radar (InSAR) observations from satellite and aircraft platforms have been used to produce maps of subsidence with ~cm accuracy. For this study, we have obtained and analyzed Japanese PALSAR data for 2006 - 2011, Canadian Radarsat-1 data for 2011 - 2013, Radarsat-2 data for 2012 - 2015, and ESA's Sentinel-1A for 2015 and produced maps of subsidence for those periods. High resolution InSAR data were also acquired along the <span class="hlt">California</span> Aqueduct by the NASA UAVSAR from 2013 - 2015. Using multiple scenes acquired by these systems, we were able to produce the time histories of subsidence at selected locations and transects showing how subsidence varies both spatially and temporally. The maps show that subsidence is continuing in areas with a history of subsidence and that the rates and areas affected have increased due to increased groundwater extraction during the extended western US drought. The high resolution maps from UAVSAR were used to identify and quantify new, highly localized areas of accelerated subsidence along the <span class="hlt">California</span> Aqueduct that occurred in 2014. The <span class="hlt">California</span> Department of Water Resources (DWR) funded this work to provide the background and an update on subsidence in the Central <span class="hlt">Valley</span> to support future policy. Geographic Information System (GIS) files are being furnished to DWR for further analysis of the 4 dimensional subsidence time-series maps. Part of this work was carried out at the Jet Propulsion Laboratory, <span class="hlt">California</span> Institute of Technology, under contract with NASA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.S13A1720V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.S13A1720V"><span>CISN ShakeAlert: Using early warnings for <span class="hlt">earthquakes</span> in <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vinci, M.; Hellweg, M.; Jones, L. M.; Khainovski, O.; Schwartz, K.; Lehrer, D.; Allen, R. M.; Neuhauser, D. S.</p> <p>2009-12-01</p> <p>Educated users who have developed response plans and procedures are just as important for an <span class="hlt">earthquake</span> early warning (EEW) system as are the algorithms and computers that process the data and produce the warnings. In Japan, for example, the implementation of the EEW system which now provides advanced alerts of ground shaking included intense outreach efforts to both institutional and individual recipients. Alerts are now used in automatic control systems that stop trains, place sensitive equipment in safe mode and isolate hazards while the public takes cover. In <span class="hlt">California</span>, the <span class="hlt">California</span> Integrated Seismic Network (CISN) is now developing and implementing components of a prototype system for EEW, ShakeAlert. As this processing system is developed, we invite a suite of perspective users from critical industries and institutions throughout <span class="hlt">California</span> to partner with us in developing useful ShakeAlert products and procedures. At the same time, we will support their efforts to determine and implement appropriate responses to an early warning of <span class="hlt">earthquake</span> shaking. As a first step, in a collaboration with BART, we have developed a basic system allowing BART’s operation center to receive realtime ground shaking information from more than 150 seismic stations operating in the San Francisco Bay Area. BART engineers are implementing a display system for this information. Later phases will include the development of improved response procedures utilizing this information. We plan to continue this collaboration to include more sophisticated information from the prototype CISN ShakeAlert system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.S34A..03K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.S34A..03K"><span>Impact of a Large San Andreas Fault <span class="hlt">Earthquake</span> on Tall Buildings in Southern <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Krishnan, S.; Ji, C.; Komatitsch, D.; Tromp, J.</p> <p>2004-12-01</p> <p>In 1857, an <span class="hlt">earthquake</span> of magnitude 7.9 occurred on the San Andreas fault, starting at Parkfield and rupturing in a southeasterly direction for more than 300~km. Such a unilateral rupture produces significant directivity toward the San Fernando and Los Angeles basins. The strong shaking in the basins due to this <span class="hlt">earthquake</span> would have had a significant long-period content (2--8~s). If such motions were to happen today, they could have a serious impact on tall buildings in Southern <span class="hlt">California</span>. In order to study the effects of large San Andreas fault <span class="hlt">earthquakes</span> on tall buildings in Southern <span class="hlt">California</span>, we use the finite source of the magnitude 7.9 2001 Denali fault <span class="hlt">earthquake</span> in Alaska and map it onto the San Andreas fault with the rupture originating at Parkfield and proceeding southward over a distance of 290~km. Using the SPECFEM3D spectral element seismic wave propagation code, we simulate a Denali-like <span class="hlt">earthquake</span> on the San Andreas fault and compute ground motions at sites located on a grid with a 2.5--5.0~km spacing in the greater Southern <span class="hlt">California</span> region. We subsequently analyze 3D structural models of an existing tall steel building designed in 1984 as well as one designed according to the current building code (Uniform Building Code, 1997) subjected to the computed ground motion. We use a sophisticated nonlinear building analysis program, FRAME3D, that has the ability to simulate damage in buildings due to three-component ground motion. We summarize the performance of these structural models on contour maps of carefully selected structural performance indices. This study could benefit the city in laying out emergency response strategies in the event of an <span class="hlt">earthquake</span> on the San Andreas fault, in undertaking appropriate retrofit measures for tall buildings, and in formulating zoning regulations for new construction. In addition, the study would provide risk data associated with existing and new construction to insurance companies, real estate developers, and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.S43D2839T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.S43D2839T"><span>Near Fault Strong Ground Motion Records in the Kathmandu <span class="hlt">Valley</span> during the 2015 Gorkha Nepal <span class="hlt">Earthquake</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Takai, N.; Shigefuji, M.; Rajaure, S.; Bijukchhen, S.; Ichiyanagi, M.; Dhital, M. R.; Sasatani, T.</p> <p>2015-12-01</p> <p>Kathmandu is the capital of Nepal and is located in the Kathmandu <span class="hlt">Valley</span>, which is formed by soft lake sediments of Plio-Pleistocene origin. Large <span class="hlt">earthquakes</span> in the past have caused significant damage as the seismic waves were amplified in the soft sediments. To understand the site effect of the <span class="hlt">valley</span> structure, we installed continuous recording accelerometers in four different parts of the <span class="hlt">valley</span>. Four stations were installed along a west-to-east profile of the <span class="hlt">valley</span> at KTP (Kirtipur; hill top), TVU (Kirtipur; hill side), PTN (Patan) and THM (Thimi). On 25 April 2015, a large interplate <span class="hlt">earthquake</span> Mw 7.8 occurred in the Himalayan Range of Nepal. The focal area estimated was about 200 km long and 150 km wide, with a large slip area under the Kathmandu <span class="hlt">Valley</span> where our strong motion observation stations were installed. The strong ground motions were observed during this large damaging <span class="hlt">earthquake</span>. The maximum horizontal peak ground acceleration at the rock site was 271 cm s-2, and the maximum horizontal peak ground velocity at the sediment sites reached 112 cm s-1. We compared these values with the empirical attenuation formula for strong ground motions. We found the peak accelerations were smaller and the peak velocities were approximately the same as the predicted values. The rock site KTP motions are less affected by site amplification and were analysed further. The horizontal components were rotated to the fault normal (N205E) and fault parallel (N115E) directions using the USGS fault model. The velocity waveforms at KTP showed about 5 s triangular pulses on the N205E and the up-down components; however the N115E component was not a triangular pulse but one cycle sinusoidal wave. The velocity waveforms at KTP were integrated to derive the displacement waveforms. The derived displacements at KTP are characterized by a monotonic step on the N205E normal and up-down components. The displacement waveforms of KTP show permanent displacements of 130 cm in the fault</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20176346','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20176346"><span>Contaminated fish consumption in <span class="hlt">California</span>'s Central <span class="hlt">Valley</span> Delta.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shilling, Fraser; White, Aubrey; Lippert, Lucas; Lubell, Mark</p> <p>2010-05-01</p> <p>Extensive mercury contamination and angler selection of the most contaminated fish species coincide in <span class="hlt">California</span>'s Central <span class="hlt">Valley</span>. This has led to a policy conundrum: how to balance the economic and cultural impact of advising subsistence anglers to eat less fish with the economic cost of reducing the mercury concentrations in fish? State agencies with regulatory and other jurisdictional authority lack sufficient data and have no consistent approach to this problem. The present study focused on a critical and contentious region in <span class="hlt">California</span>'s Central <span class="hlt">Valley</span> (the Sacramento-San Joaquin Rivers Delta) where mercury concentrations in fish and subsistence fishing rates are both high. Anglers and community members were surveyed for their fish preferences, rates of consumption, the ways that they receive health information, and basic demographic information. The rates of fish consumption for certain ethnicities were higher than the rates used by state agencies for planning pollution remediation. A broad range of ethnic groups were involved in catching and eating fish. The majority of anglers reported catching fish in order to feed to their families, including children and women of child-bearing age. There were varied preferences for receiving health information and no correlation between knowledge of fish contamination and rates of consumption. Calculated rates of mercury intake by subsistence anglers were well above the EPA reference dose. The findings here support a comprehensive policy strategy of involvement of the diverse communities in decision-making about education and clean-up and an official recognition of subsistence fishers in the region. Copyright 2010 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/pp/1552b/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/pp/1552b/report.pdf"><span>Chapter B. The Loma Prieta, <span class="hlt">California</span>, <span class="hlt">Earthquake</span> of October 17, 1989 - Highway Systems</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Yashinsky, Mark</p> <p>1998-01-01</p> <p>This paper summarizes the impact of the Loma Prieta <span class="hlt">earthquake</span> on highway systems. City streets, urban freeways, county roads, state routes, and the national highway system were all affected. There was damage to bridges, roads, tunnels, and other highway structures. The most serious damage occurred in the cities of San Francisco and Oakland, 60 miles from the fault rupture. The cost to repair and replace highways damaged by this <span class="hlt">earthquake</span> was $2 billion. About half of this cost was to replace the Cypress Viaduct, a long, elevated double-deck expressway that had a devastating collapse which resulted in 42 deaths and 108 injuries. The <span class="hlt">earthquake</span> also resulted in some positive changes for highway systems. Research on bridges and <span class="hlt">earthquakes</span> began to be funded at a much higher level. Retrofit programs were started to upgrade the seismic performance of the nation's highways. The Loma Prieta <span class="hlt">earthquake</span> changed <span class="hlt">earthquake</span> policy and engineering practice for highway departments not only in <span class="hlt">California</span>, but all over the world.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70117207','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70117207"><span>Paleoseismology of the Southern Section of the Black Mountains and Southern Death <span class="hlt">Valley</span> Fault Zones, Death <span class="hlt">Valley</span>, United States</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sohn, Marsha S.; Knott, Jeffrey R.; Mahan, Shannon</p> <p>2014-01-01</p> <p>The Death <span class="hlt">Valley</span> Fault System (DVFS) is part of the southern Walker Lane–eastern <span class="hlt">California</span> shear zone. The normal Black Mountains Fault Zone (BMFZ) and the right-lateral Southern Death <span class="hlt">Valley</span> Fault Zone (SDVFZ) are two components of the DVFS. Estimates of late Pleistocene-Holocene slip rates and recurrence intervals for these two fault zones are uncertain owing to poor relative age control. The BMFZ southernmost section (Section 1W) steps basinward and preserves multiple scarps in the Quaternary alluvial fans. We present optically stimulated luminescence (OSL) dates ranging from 27 to 4 ka of fluvial and eolian sand lenses interbedded with alluvial-fan deposits offset by the BMFZ. By cross-cutting relations, we infer that there were three separate ground-rupturing <span class="hlt">earthquakes</span> on BMFZ Section 1W with vertical displacement between 5.5 m and 2.75 m. The slip-rate estimate is ∼0.2 to 1.8 mm/yr, with an <span class="hlt">earthquake</span> recurrence interval of 4,500 to 2,000 years. Slip-per-event measurements indicate Mw 7.0 to 7.2 <span class="hlt">earthquakes</span>. The 27–4-ka OSL-dated alluvial fans also overlie the putative Cinder Hill tephra layer. Cinder Hill is offset ∼213 m by SDVFZ, which yields a tentative slip rate of 1 to 8 mm/yr for the SDVFZ.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/wsp/2370b/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wsp/2370b/report.pdf"><span>Geology and water resources of Owens <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hollett, Kenneth J.; Danskin, Wesley R.; McCaffrey, William F.; Walti, Caryl L.</p> <p>1991-01-01</p> <p>Owens <span class="hlt">Valley</span>, a long, narrow <span class="hlt">valley</span> located along the east flank of the Sierra Nevada in east-central <span class="hlt">California</span>, is the main source of water for the city of Los Angeles. The city diverts most of the surface water in the <span class="hlt">valley</span> into the Owens River-Los Angeles Aqueduct system, which transports the water more than 200 miles south to areas of distribution and use. Additionally, ground water is pumped or flows from wells to supplement the surface-water diversions to the river-aqueduct system. Pumpage from wells needed to supplement water export has increased since 1970, when a second aqueduct was put into service, and local concerns have been expressed that the increased pumpage may have had a detrimental effect on the environment and the indigenous alkaline scrub and meadow plant communities in the <span class="hlt">valley</span>. The scrub and meadow communities depend on soil moisture derived from precipitation and the unconfined part of a multilayered aquifer system. This report, which describes the hydrogeology of the aquifer system and the water resources of the <span class="hlt">valley</span>, is one in a series designed to (1) evaluate the effects that groundwater pumping has on scrub and meadow communities and (2) appraise alternative strategies to mitigate any adverse effects caused by, pumping. Two principal topographic features are the surface expression of the geologic framework--the high, prominent mountains on the east and west sides of the <span class="hlt">valley</span> and the long, narrow intermountain <span class="hlt">valley</span> floor. The mountains are composed of sedimentary, granitic, and metamorphic rocks, mantled in part by volcanic rocks as well as by glacial, talus, and fluvial deposits. The <span class="hlt">valley</span> floor is underlain by <span class="hlt">valley</span> fill that consists of unconsolidated to moderately consolidated alluvial fan, transition-zone, glacial and talus, and fluvial and lacustrine deposits. The <span class="hlt">valley</span> fill also includes interlayered recent volcanic flows and pyroclastic rocks. The bedrock surface beneath the <span class="hlt">valley</span> fill is a narrow, steep-sided graben</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006IJBm...50..174Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006IJBm...50..174Z"><span>Climate controls on <span class="hlt">valley</span> fever incidence in Kern County, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zender, Charles S.; Talamantes, Jorge</p> <p>2006-01-01</p> <p>Coccidiodomycosis (<span class="hlt">valley</span> fever) is a systemic infection caused by inhalation of airborne spores from Coccidioides immitis, a soil-dwelling fungus found in the southwestern United States, parts of Mexico, and Central and South America. Dust storms help disperse C. immitis so risk factors for <span class="hlt">valley</span> fever include conditions favorable for fungal growth (moist, warm soil) and for aeolian soil erosion (dry soil and strong winds). Here, we analyze and inter-compare the seasonal and inter-annual behavior of <span class="hlt">valley</span> fever incidence and climate risk factors for the period 1980-2002 in Kern County, <span class="hlt">California</span>, the US county with highest reported incidence. We find weak but statistically significant links between disease incidence and antecedent climate conditions. Precipitation anomalies 8 and 20 months antecedent explain only up to 4% of monthly variability in subsequent <span class="hlt">valley</span> fever incidence during the 23 year period tested. This is consistent with previous studies suggesting that C. immitis tolerates hot, dry periods better than competing soil organisms and, as a result, thrives during wet periods following droughts. Furthermore, the relatively small correlation with climate suggests that the causes of <span class="hlt">valley</span> fever in Kern County could be largely anthropogenic. Seasonal climate predictors of <span class="hlt">valley</span> fever in Kern County are similar to, but much weaker than, those in Arizona, where previous studies find precipitation explains up to 75% of incidence. Causes for this discrepancy are not yet understood. Higher resolution temporal and spatial monitoring of soil conditions could improve our understanding of climatic antecedents of severe epidemics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70036013','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70036013"><span>Nonlinear site response in medium magnitude <span class="hlt">earthquakes</span> near Parkfield, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Rubinstein, Justin L.</p> <p>2011-01-01</p> <p>Careful analysis of strong-motion recordings of 13 medium magnitude <span class="hlt">earthquakes</span> (3.7 ≤ M ≤ 6.5) in the Parkfield, <span class="hlt">California</span>, area shows that very modest levels of shaking (approximately 3.5% of the acceleration of gravity) can produce observable changes in site response. Specifically, I observe a drop and subsequent recovery of the resonant frequency at sites that are part of the USGS Parkfield dense seismograph array (UPSAR) and Turkey Flat array. While further work is necessary to fully eliminate other models, given that these frequency shifts correlate with the strength of shaking at the Turkey Flat array and only appear for the strongest shaking levels at UPSAR, the most plausible explanation for them is that they are a result of nonlinear site response. Assuming this to be true, the observation of nonlinear site response in small (M M 6.5 San Simeon <span class="hlt">earthquake</span> and the 2004 M 6 Parkfield <span class="hlt">earthquake</span>).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70022549','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70022549"><span>The 1998 <span class="hlt">earthquake</span> sequence south of Long <span class="hlt">Valley</span> Caldera, <span class="hlt">California</span>: Hints of magmatic involvement</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hough, S.E.; Dollar, R.S.; Johnson, P.</p> <p>2000-01-01</p> <p>A significant episode of seismic and geodetic unrest took place at Long <span class="hlt">Valley</span> Caldera, <span class="hlt">California</span>, beginning in the summer of 1997. Activity through late May of 1998 was concentrated in and around the south moat and the south margin of the resurgent dome. The Sierran Nevada block (SNB) region to the south/southeast remained relatively quiet until a M 5.1 event occurred there on 9 June 1998 (UT). A second M 5.1 event followed on 15 July (UT); both events were followed by appreciable aftershock sequences. An additional, distinct burst of activity began on 1 August 1998. The number of events in the August sequence (over the first week or two) was similar to the aftershock sequence of the 15 July 1998 M 5.1 event, but the later sequence was not associated with any events larger than M 4.3. All of the summer 1998 SNB activity was considered tectonic rather than magmatic; in general the SNB is considered an unlikely location for future eruptions. However, the August sequence-an 'aftershock sequence without a mainshock'-is suggestive of a strain event larger than the cumulative seismotectonic strain release. Moreover, a careful examination of waveforms from the August sequence reveals a small handful of events whose spectral signature is strikingly harmonic. We investigate the waveforms of these events using spectral, autocorrelation, and empirical Green's function techniques and conclude that they were most likely associated with a fluid-controlled source. Our observations suggest that there may have been some degree of magma or magma-derived fluid involvement in the 1998 SNB sequence.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/5341989-contrasts-between-source-parameters-earthquakes-northern-baja-california-southern-california','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/5341989-contrasts-between-source-parameters-earthquakes-northern-baja-california-southern-california"><span>Contrasts between source parameters of M [>=] 5. 5 <span class="hlt">earthquakes</span> in northern Baja <span class="hlt">California</span> and southern <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Doser, D.I.</p> <p>1993-04-01</p> <p>Source parameters determined from the body waveform modeling of large (M [>=] 5.5) historic <span class="hlt">earthquakes</span> occurring between 1915 and 1956 along the San Jacinto and Imperial fault zones of southern <span class="hlt">California</span> and the Cerro Prieto, Tres Hermanas and San Miguel fault zones of Baja <span class="hlt">California</span> have been combined with information from post-1960's events to study regional variations in source parameters. The results suggest that large <span class="hlt">earthquakes</span> along the relatively young San Miguel and Tres Hermanas fault zones have complex rupture histories, small source dimensions (< 25 km), high stress drops (60 bar average), and a high incidence of foreshock activity.more » This may be a reflection of the rough, highly segmented nature of the young faults. In contrast, Imperial-Cerro Prieto events of similar magnitude have low stress drops (16 bar average) and longer rupture lengths (42 km average), reflecting rupture along older, smoother fault planes. Events along the San Jacinto fault zone appear to lie in between these two groups. These results suggest a relationship between the structural and seismological properties of strike-slip faults that should be considered during seismic risk studies.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H23P..04F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H23P..04F"><span>Subsidence and Rebound in <span class="hlt">California</span>'s Central <span class="hlt">Valley</span>: Effects of Pumping, Geology, and Precipitation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Farr, T. G.; Fairbanks, A.</p> <p>2017-12-01</p> <p>Recent rains in <span class="hlt">California</span> caused a pause, and even a reversal in some areas, of the subsidence that has plagued the Central <span class="hlt">Valley</span> for decades. The 3 main drivers of surface deformation in the Central <span class="hlt">Valley</span> are: Subsurface hydro-geology, precipitation and surface water deliveries, and groundwater pumping. While the geology is relatively fixed in time, water inputs and outputs vary greatly both in time and space. And while subsurface geology and water inputs are reasonably well-known, information about groundwater pumping amounts and rates is virtually non-existent in <span class="hlt">California</span>. We have derived regional maps of surface deformation in the region for the period 2006 - present which allow reconstruction of seasonal and long-term changes. In order to understand the spatial and temporal patterns of subsidence and rebound in the Central <span class="hlt">Valley</span>, we have been compiling information on the geology and water inputs and have attempted to infer pumping rates using maps of fallowed fields and published pumping information derived from hydrological models. In addition, the spatial and temporal patterns of hydraulic head as measured in wells across the region allow us to infer the spatial and temporal patterns of groundwater pumping and recharge more directly. A better understanding of how different areas (overlying different stratigraphy) of the Central <span class="hlt">Valley</span> respond to water inputs and outputs will allow a predictive capability, potentially defining sustainable pumping rates related to water inputs. * work performed under contract to NASA and the CA Dept. of Water Resources</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2006/3120/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2006/3120/"><span>Ground-water modeling of the Death <span class="hlt">Valley</span> Region, Nevada and <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Belcher, W.R.; Faunt, C.C.; Sweetkind, D.S.; Blainey, J.B.; San Juan, C. A.; Laczniak, R.J.; Hill, M.C.</p> <p>2006-01-01</p> <p>The Death <span class="hlt">Valley</span> regional ground-water flow system (DVRFS) of southern Nevada and eastern <span class="hlt">California</span> covers an area of about 100,000 square kilometers and contains very complex geology and hydrology. Using a computer model to represent the complex system, the U.S. Geological Survey simulated ground-water flow in the Death <span class="hlt">Valley</span> region for use with U.S. Department of Energy projects in southern Nevada. The model was created to help address contaminant cleanup activities associated with the underground nuclear testing conducted from 1951 to 1992 at the Nevada Test Site and to support the licensing process for the proposed geologic repository for high-level nuclear waste at Yucca Mountain, Nevada.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007IJBm...51..307T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007IJBm...51..307T"><span>Statistical modeling of <span class="hlt">valley</span> fever data in Kern County, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Talamantes, Jorge; Behseta, Sam; Zender, Charles S.</p> <p>2007-03-01</p> <p>Coccidioidomycosis (<span class="hlt">valley</span> fever) is a fungal infection found in the southwestern US, northern Mexico, and some places in Central and South America. The fungus that causes it ( Coccidioides immitis) is normally soil-dwelling but, if disturbed, becomes air-borne and infects the host when its spores are inhaled. It is thus natural to surmise that weather conditions that foster the growth and dispersal of the fungus must have an effect on the number of cases in the endemic areas. We present here an attempt at the modeling of <span class="hlt">valley</span> fever incidence in Kern County, <span class="hlt">California</span>, by the implementation of a generalized auto regressive moving average (GARMA) model. We show that the number of <span class="hlt">valley</span> fever cases can be predicted mainly by considering only the previous history of incidence rates in the county. The inclusion of weather-related time sequences improves the model only to a relatively minor extent. This suggests that fluctuations of incidence rates (about a seasonally varying background value) are related to biological and/or anthropogenic reasons, and not so much to weather anomalies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA01749.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA01749.html"><span>space Radar Image of Long <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>1999-05-01</p> <p>An area near Long <span class="hlt">Valley</span>, <span class="hlt">California</span>, was mapped by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar aboard the space shuttle Endeavor on April 13, 1994, during the first flight of the radar instrument, and on October 4, 1994, during the second flight of the radar instrument. The orbital configurations of the two data sets were ideal for interferometric combination -- that is overlaying the data from one image onto a second image of the same area to create an elevation map and obtain estimates of topography. Once the topography is known, any radar-induced distortions can be removed and the radar data can be geometrically projected directly onto a standard map grid for use in a geographical information system. The 50 kilometer by 50 kilometer (31 miles by 31 miles) map shown here is entirely derived from SIR-C L-band radar (horizontally transmitted and received) results. The color shown in this image is produced from the interferometrically determined elevations, while the brightness is determined by the radar backscatter. The map is in Universal Transverse Mercator (UTM) coordinates. Elevation contour lines are shown every 50 meters (164 feet). Crowley Lake is the dark feature near the south edge of the map. The Adobe <span class="hlt">Valley</span> in the north and the Long <span class="hlt">Valley</span> in the south are separated by the Glass Mountain Ridge, which runs through the center of the image. The height accuracy of the interferometrically derived digital elevation model is estimated to be 20 meters (66 feet) in this image. http://photojournal.jpl.nasa.gov/catalog/PIA01749</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.S21C..08J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.S21C..08J"><span>Prospective Tests of Southern <span class="hlt">California</span> <span class="hlt">Earthquake</span> Forecasts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jackson, D. D.; Schorlemmer, D.; Gerstenberger, M.; Kagan, Y. Y.; Helmstetter, A.; Wiemer, S.; Field, N.</p> <p>2004-12-01</p> <p>We are testing <span class="hlt">earthquake</span> forecast models prospectively using likelihood ratios. Several investigators have developed such models as part of the Southern <span class="hlt">California</span> <span class="hlt">Earthquake</span> Center's project called Regional <span class="hlt">Earthquake</span> Likelihood Models (RELM). Various models are based on fault geometry and slip rates, seismicity, geodetic strain, and stress interactions. Here we describe the testing procedure and present preliminary results. Forecasts are expressed as the yearly rate of <span class="hlt">earthquakes</span> within pre-specified bins of longitude, latitude, magnitude, and focal mechanism parameters. We test models against each other in pairs, which requires that both forecasts in a pair be defined over the same set of bins. For this reason we specify a standard "menu" of bins and ground rules to guide forecasters in using common descriptions. One menu category includes five-year forecasts of magnitude 5.0 and larger. Contributors will be requested to submit forecasts in the form of a vector of yearly <span class="hlt">earthquake</span> rates on a 0.1 degree grid at the beginning of the test. Focal mechanism forecasts, when available, are also archived and used in the tests. Interim progress will be evaluated yearly, but final conclusions would be made on the basis of cumulative five-year performance. The second category includes forecasts of <span class="hlt">earthquakes</span> above magnitude 4.0 on a 0.1 degree grid, evaluated and renewed daily. Final evaluation would be based on cumulative performance over five years. Other types of forecasts with different magnitude, space, and time sampling are welcome and will be tested against other models with shared characteristics. Tests are based on the log likelihood scores derived from the probability that future <span class="hlt">earthquakes</span> would occur where they do if a given forecast were true [Kagan and Jackson, J. Geophys. Res.,100, 3,943-3,959, 1995]. For each pair of forecasts, we compute alpha, the probability that the first would be wrongly rejected in favor of the second, and beta, the probability</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.S12C..05M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.S12C..05M"><span>Historigraphical analysis of the 1857 Ft. Tejon <span class="hlt">earthquake</span>, San Andreas Fault, <span class="hlt">California</span>: Preliminary results</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Martindale, D.; Evans, J. P.</p> <p>2002-12-01</p> <p>Past historical analyses of the 1857 Forth Tejon <span class="hlt">earthquake</span> include Townley and Allen (1939); Wood (1955) re-examined the <span class="hlt">earthquake</span> and added some additional new material, and Agnew and Sieh (1978) published an extensive review of the previous publications and included primary sources not formerly known. Since 1978, most authors have reiterated the findings of Agnew and Sieh, with the exception of Meltzner and Wald's 1998 work that built on Sieh's foreshock research and included an extensive study of aftershocks. Approximately twenty-five years has past since the last full investigation of the event. In the last several decades, libraries and archives have continued to gather additional documents. Staff members continually inventory new and existing collections, making them accessible to researchers today. As a result, we are conducting an updated examination, with the hope of new insight regarding the 1857 Fort Tejon <span class="hlt">earthquake</span>. We use a new approached to the topic: the research skills of a historian in collaboration with a geologist to generate quantitative data on the nature and location of ground shaking associated with the <span class="hlt">earthquake</span>. We analyze documents from the Huntington Library, <span class="hlt">California</span> State Historical Society, <span class="hlt">California</span> State Library-<span class="hlt">California</span> Room, Utah Historical Association Information Center, the Church of Jesus Christ of Latter-day Saints (LDS) Archives and Historical Department, Cal Tech Archives, the National Archives, and the Fort Tejon State Park. New facilities reviewed also include Utah State University, University of Utah, and the LDS Family History Center. Each facility not only provided formerly quoted sources, but many offered new materials. For example, previous scholars examined popular, well-known newspapers; yet, publications in smaller towns and in languages other than English, also existed. Thirty newspapers published in January 1857 were located. We find records of the event at least one year after the <span class="hlt">earthquake</span>. One outcome</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70019804','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70019804"><span>Reduction of <span class="hlt">earthquake</span> risk in the united states: Bridging the gap between research and practice</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hays, W.W.</p> <p>1998-01-01</p> <p>Continuing efforts under the auspices of the National <span class="hlt">Earthquake</span> Hazards Reduction Program are under way to improve <span class="hlt">earthquake</span> risk assessment and risk management in <span class="hlt">earthquake</span>-prone regions of Alaska, <span class="hlt">California</span>, Nevada, Washington, Oregon, Arizona, Utah, Wyoming, and Idaho, the New Madrid and Wabash <span class="hlt">Valley</span> seismic zones in the central United States, the southeastern and northeastern United States, Puerto Rico, Virgin Islands, Guam, and Hawaii. Geologists, geophysicists, seismologists, architects, engineers, urban planners, emergency managers, health care specialists, and policymakers are having to work at the margins of their disciplines to bridge the gap between research and practice and to provide a social, technical, administrative, political, legal, and economic basis for changing public policies and professional practices in communities where the <span class="hlt">earthquake</span> risk is unacceptable. ?? 1998 IEEE.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730012588','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730012588"><span>Structural and lithologic study of northern coast ranges and Sacramento <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rich, E. I. (Principal Investigator)</p> <p>1973-01-01</p> <p>The author has identified the following significant results. Analysis of ERTS-1 imagery of the Northern <span class="hlt">California</span> Coast Ranges has disclosed a potential relation between a heretofore unrecognized fracture system and known deposits of mercury and geothermally active areas in the Coast Range and between oil and gas fields in the Sacramento <span class="hlt">Valley</span>. Three potentially important systems of linear elements within the Coast Ranges, detected on ERTS-1 imagery, may represent fault systems or zones of shearing because topographic offset and stratigraph disruption can be seen along one or two of the lineations. One of the systems in subparallel to the San Andreas fault and is confined to the Pacific Coastal Belt. Another set is confined to the central core of the Coast Ranges. The third set of linear features (<span class="hlt">Valley</span> System) has not heretofore been recognized. Some of the known mercury deposits and geothermally active areas near Clear Lake, in the Coast Ranges, are along the <span class="hlt">Valley</span> System or at the intersection of the Central and <span class="hlt">Valley</span> Systems. The plotted locations of some of the oil and gas fields in the Sacramento <span class="hlt">Valley</span> are associated with the <span class="hlt">Valley</span> and/or Central Systems. If these relations prove reliable, the ERTS-1 imagery may prove to be an extremely useful exploration tool.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA01808&hterms=deposit+alluvial&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddeposit%2Balluvial','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA01808&hterms=deposit+alluvial&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddeposit%2Balluvial"><span>Space Radar Image of Saline <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1999-01-01</p> <p>This is a three-dimensional perspective view of Saline <span class="hlt">Valley</span>, about 30 km (19 miles) east of the town of Independence, <span class="hlt">California</span> created by combining two spaceborne radar images using a technique known as interferometry. Visualizations like this one are helpful to scientists because they clarify the relationships of the different types of surfaces detected by the radar and the shapes of the topographic features such as mountains and <span class="hlt">valleys</span>. The view is looking southwest across Saline <span class="hlt">Valley</span>. The high peaks in the background are the Inyo Mountains, which rise more than 3,000 meters (10,000 feet) above the <span class="hlt">valley</span> floor. The dark blue patch near the center of the image is an area of sand dunes. The brighter patches to the left of the dunes are the dry, salty lake beds of Saline <span class="hlt">Valley</span>. The brown and orange areas are deposits of boulders, gravel and sand known as alluvial fans. The image was constructed by overlaying a color composite radar image on top of a digital elevation map. The radar image was taken by the Spaceborne Imaging Radar-C/X-bandSynthetic Aperture Radar (SIR-C/X-SAR) on board the space shuttleEndeavour in October 1994. The digital elevation map was producedusing radar interferometry, a process in which radar data are acquired on different passes of the space shuttle. The two data passes are compared to obtain elevation information. The elevation data were derived from a 1,500-km-long (930-mile) digital topographic map processed at JPL. Radar image data are draped over the topography to provide the color with the following assignments: red is L-band vertically transmitted, vertically received; green is C-band vertically transmitted, vetically received; and blue is the ratio of C-band vertically transmitted, vertically received to L-band vertically transmitted, vertically received. This image is centered near 36.8 degrees north latitude and 117.7 degrees west longitude. No vertical exaggeration factor has been applied to the data. SIR-C/X-SAR, a joint</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA02789&hterms=time+perspective&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dtime%2Bperspective','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA02789&hterms=time+perspective&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dtime%2Bperspective"><span>SRTM Perspective View with Landsat Overlay: Santa Paula, and Santa Clara River <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2000-01-01</p> <p>Rectangular fields of the agriculturally rich Santa Clara River <span class="hlt">Valley</span> are visible in this perspective view generated using data from the Shuttle Radar Topography Mission and an enhanced Landsat image. The Santa Clara River, which lends its name to this <span class="hlt">valley</span>, flows from headwaters near Acton, <span class="hlt">California</span>, 160 km (100 miles) to the Pacific Ocean, and is one of only two natural river systems remaining in southern <span class="hlt">California</span>. In the foreground of this image, the largely dry riverbed can be seen as a bright feature as it winds its way along the base of South Mountain. The bright region at the right end of this portion of the <span class="hlt">valley</span> is the city of Santa Paula, <span class="hlt">California</span>. Founded in 1902, this small, picturesque town at the geographic center of Ventura County is referred to as the 'Citrus Capital of the World.' The city is surrounded by orange, lemon, and avocado groves and is a major distribution point for citrus fruits in the United States. The bright, linear feature in the center of the <span class="hlt">valley</span> is State Highway 126, the <span class="hlt">valley</span>'s 'main drag.' For visualization purposes, topographic heights displayed in this image are exaggerated two times. Colors, from Landsat data, approximate natural color.<p/>The elevation data used in this image was acquired by SRTM aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of Earth's land surface. To collect the 3-D SRTM data, engineers added a mast 60 meters (about 200 feet)long, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense, and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2012-03-01/pdf/2012-4675.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2012-03-01/pdf/2012-4675.pdf"><span>77 FR 12527 - Revisions to the <span class="hlt">California</span> State Implementation Plan, Antelope <span class="hlt">Valley</span> Air Quality Management...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2012-03-01</p> <p>...EPA is proposing to approve revisions to the Antelope <span class="hlt">Valley</span> Air Quality Management District (AVAQMD) and San Joaquin <span class="hlt">Valley</span> Unified Air Pollution Control District (SJVUAPCD) portions of the <span class="hlt">California</span> State Implementation Plan (SIP). These revisions concern negative declarations for volatile organic compound (VOC) and oxides of sulfur source categories. We are proposing to approve these negative declarations under the Clean Air Act as amended in 1990 (CAA or the Act).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A53M3410P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A53M3410P"><span>Transboundary Contributions To Surface Ozone In <span class="hlt">California</span>'s Central <span class="hlt">Valley</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Post, A.; Faloona, I. C.; Conley, S. A.; Lighthall, D.</p> <p>2014-12-01</p> <p>Rising concern over the impacts of exogenous air pollution in <span class="hlt">California</span>'s Central <span class="hlt">Valley</span> has prompted the establishment of a coastal, high altitude monitoring site at the Chews Ridge Observatory (1550 m) approximately 30 km east of Point Sur in Monterey County, under the auspices of the Monterey Institute for Research in Astronomy. Two and a half years of continuous ozone data are presented in the context of long-range transport and its potential impact on surface air quality in the San Joaquin <span class="hlt">Valley</span> (SJV). Past attempts to quantify the impact of transboundary ozone on surface levels have relied on uncertain model estimates, or have been limited to weekly ozonesonde data. Here, we present an observationally derived quantification of the contribution of free tropospheric ozone to surface sites in the San Joaquin <span class="hlt">Valley</span> throughout three ozone seasons (June through September, 2012-2014). The diurnal ozone patterns at Chews Ridge, and their correlations with ozone aloft over the <span class="hlt">Valley</span>, have been presented previously. Furthermore, reanalysis data of geopotential heights indicate consistent flow from Chews Ridge to the East, directly over the SJV. In a related airborne project we quantify the vertical exchange, or entrainment, rate over the Southern SJV from a series of focused flights measuring ozone concentrations during peak photochemical hours in conjunction with local meteorological data to quantify an ozone budget for the area. By applying the entrainment rates observed in that study here we are able to quantify the seasonal contributions of free tropospheric ozone measured at Chews Ridge to surface sites in the San Joaquin <span class="hlt">Valley</span>, and compare prior model estimates to our observationally derived values.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.T43D3041W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.T43D3041W"><span>Relative Contributions of Geothermal Pumping and Long-Term <span class="hlt">Earthquake</span> Rate to Seismicity at <span class="hlt">California</span> Geothermal Fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Weiser, D. A.; Jackson, D. D.</p> <p>2015-12-01</p> <p>In a tectonically active area, a definitive discrimination between geothermally-induced and tectonic <span class="hlt">earthquakes</span> is difficult to achieve. We focus our study on <span class="hlt">California</span>'s 11 major geothermal fields: Amedee, Brawley, Casa Diablo, Coso, East Mesa, The Geysers, Heber, Litchfield, Salton Sea, Susanville, and Wendel. The Geysers geothermal field is the world's largest geothermal energy producer. <span class="hlt">California</span>'s Department of Oil Gas and Geothermal Resources provides field-wide monthly injection and production volumes for each of these sites, which allows us to study the relationship between geothermal pumping activities and seismicity. Since many of the geothermal fields began injecting and producing before nearby seismic stations were installed, we use smoothed seismicity since 1932 from the ANSS catalog as a proxy for tectonic <span class="hlt">earthquake</span> rate. We examine both geothermal pumping and long-term <span class="hlt">earthquake</span> rate as factors that may control <span class="hlt">earthquake</span> rate. Rather than focusing only on the largest <span class="hlt">earthquake</span>, which is essentially a random occurrence in time, we examine how M≥4 <span class="hlt">earthquake</span> rate density (probability per unit area, time, and magnitude) varies for each field. We estimate relative contributions to the observed <span class="hlt">earthquake</span> rate of M≥4 from both a long-term <span class="hlt">earthquake</span> rate (Kagan and Jackson, 2010) and pumping activity. For each geothermal field, respective <span class="hlt">earthquake</span> catalogs (NCEDC and SCSN) are complete above at least M3 during the test period (which we tailor to each site). We test the hypothesis that the observed <span class="hlt">earthquake</span> rate at a geothermal site during the test period is a linear combination of the long-term seismicity and pumping rates. We use a grid search to determine the confidence interval of the weighting parameters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=104902&Lab=NHEERL&keyword=UPGMA&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=104902&Lab=NHEERL&keyword=UPGMA&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>RELATIONSHIPS BETWEEN ENVIRONMENTAL VARIABLES AND BENTHIC DIATOM ASSEMBLAGES IN <span class="hlt">CALIFORNIA</span> CENTRAL <span class="hlt">VALLEY</span> STREAMS (USA)</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Streams and rivers in the <span class="hlt">California</span> Central <span class="hlt">Valley</span> Ecoregion have been substantially modified by human activities. This study examines distributional patterns of benthic diatom assemblages in relation to environmental characteristics in streams and rivers of this region. Benthic...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/20507','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/20507"><span>MANAGEMENT OF SMALL MAMMALS IN A RELICT GRASSLAND IN <span class="hlt">CALIFORNIA</span>'S CENTRAL <span class="hlt">VALLEY</span></span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>ANNE POOPATANAPONG; DOUGLAS A. KELT</p> <p>1999-01-01</p> <p>land-use patterns over the past century. In <span class="hlt">California</span>'s Central <span class="hlt">Valley</span> these changes have resulted in replacement of native grassland vegetation by non-native annual grasses. Jepson Prairie is a natural reserve that has been set aside to preserve native vernal pool and bunchgrass habitats. Jepson Prairie also provides habitat for several state and federally...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70024275','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70024275"><span>Evidence for large <span class="hlt">earthquakes</span> on the San Andreas fault at the Wrightwood, <span class="hlt">California</span> paleoseismic site: A.D. 500 to present</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fumal, T.E.; Weldon, R.J.; Biasi, G.P.; Dawson, T.E.; Seitz, G.G.; Frost, W.T.; Schwartz, D.P.</p> <p>2002-01-01</p> <p>We present structural and stratigraphic evidence from a paleoseismic site near Wrightwood, <span class="hlt">California</span>, for 14 large <span class="hlt">earthquakes</span> that occurred on the southern San Andreas fault during the past 1500 years. In a network of 38 trenches and creek-bank exposures, we have exposed a composite section of interbedded debris flow deposits and thin peat layers more than 24 m thick; fluvial deposits occur along the northern margin of the site. The site is a 150-m-wide zone of deformation bounded on the surface by a main fault zone along the northwest margin and a secondary fault zone to the southwest. Evidence for most of the 14 <span class="hlt">earthquakes</span> occurs along structures within both zones. We identify paleoearthquake horizons using infilled fissures, scarps, multiple rupture terminations, and widespread folding and tilting of beds. Ages of stratigraphic units and <span class="hlt">earthquakes</span> are constrained by historic data and 72 14C ages, mostly from samples of peat and some from plant fibers, wood, pine cones, and charcoal. Comparison of the long, well-resolved paleoseimic record at Wrightwood with records at other sites along the fault indicates that rupture lengths of past <span class="hlt">earthquakes</span> were at least 100 km long. Paleoseismic records at sites in the Coachella <span class="hlt">Valley</span> suggest that each of the past five large <span class="hlt">earthquakes</span> recorded there ruptured the fault at least as far northwest as Wrightwood. Comparisons with event chronologies at Pallett Creek and sites to the northwest suggests that approximately the same part of the fault that ruptured in 1857 may also have failed in the early to mid-sixteenth century and several other times during the past 1200 years. Records at Pallett Creek and Pitman Canyon suggest that, in addition to the 14 <span class="hlt">earthquakes</span> we document, one and possibly two other large <span class="hlt">earthquakes</span> ruptured the part of the fault including Wrightwood since about A.D. 500. These observations and elapsed times that are significantly longer than mean recurrence intervals at Wrightwood and sites to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70017543','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70017543"><span>Global positioning system surveying to monitor land subsidence in Sacramento <span class="hlt">Valley</span>, <span class="hlt">California</span>, USA</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ikehara, M.E.</p> <p>1994-01-01</p> <p>A subsidence research program began in 1985 to document the extent and magnitude of land subsidence in Sacramento <span class="hlt">Valley</span>, <span class="hlt">California</span>, an area of about 15 600 km2m, using Global Positioning System (GPS) surveying. In addition to periodic conventional spirit levelling, an examination was made of the changes in GPS-derived ellipsoidal height differences (summary differences) between pairs of adjacent bench marks in central Sacramento <span class="hlt">Valley</span> from 1986 to 1989. The average rates of land subsidence in the southern Sacramento <span class="hlt">Valley</span> for the past several decades were determined by comparing GPS-derived orthometric heights with historic published elevations. A maximum average rate of 0.053 m year-1 (0.90 m in 17 years) of subsidence has been measured. -Author</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2007/1424/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2007/1424/"><span>Geomorphology and Tectonics at the Intersection of Silurian and Death <span class="hlt">Valleys</span>, Southern <span class="hlt">California</span> - 2005 Guidebook Pacific Cell Friends of the Pleistocene</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Miller, David M.; Valin, Zenon C.</p> <p>2007-01-01</p> <p>This publication describes results from new regional and detailed surficial geologic mapping, combined with geomorphologic, geochronologic, and tectonic studies, in Silurian <span class="hlt">Valley</span> and Death <span class="hlt">Valley</span>, <span class="hlt">California</span>. The studies address a long-standing problem, the tectonic and geomorphic evolution of the intersection between three regional tectonic provinces: the eastern <span class="hlt">California</span> shear zone, the Basin and Range region of southern Nevada and adjacent <span class="hlt">California</span>, and the eastern Mojave Desert region. The chapters represent work presented on the 2005 Friends of the Pleistocene field trip and meeting as well as the field trip road log.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMNH21D..03J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMNH21D..03J"><span>A 30-year history of <span class="hlt">earthquake</span> crisis communication in <span class="hlt">California</span> and lessons for the future</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jones, L.</p> <p>2015-12-01</p> <p>The first statement from the US Geological Survey to the <span class="hlt">California</span> Office of Emergency Services quantifying the probability of a possible future <span class="hlt">earthquake</span> was made in October 1985 about the probability (approximately 5%) that a M4.7 <span class="hlt">earthquake</span> located directly beneath the Coronado Bay Bridge in San Diego would be a foreshock to a larger <span class="hlt">earthquake</span>. In the next 30 years, publication of aftershock advisories have become routine and formal statements about the probability of a larger event have been developed in collaboration with the <span class="hlt">California</span> <span class="hlt">Earthquake</span> Prediction Evaluation Council (CEPEC) and sent to CalOES more than a dozen times. Most of these were subsequently released to the public. These communications have spanned a variety of approaches, with and without quantification of the probabilities, and using different ways to express the spatial extent and the magnitude distribution of possible future events. The USGS is re-examining its approach to aftershock probability statements and to operational <span class="hlt">earthquake</span> forecasting with the goal of creating pre-vetted automated statements that can be released quickly after significant <span class="hlt">earthquakes</span>. All of the previous formal advisories were written during the <span class="hlt">earthquake</span> crisis. The time to create and release a statement became shorter with experience from the first public advisory (to the 1988 Lake Elsman <span class="hlt">earthquake</span>) that was released 18 hours after the triggering event, but was never completed in less than 2 hours. As was done for the Parkfield experiment, the process will be reviewed by CEPEC and NEPEC (National <span class="hlt">Earthquake</span> Prediction Evaluation Council) so the statements can be sent to the public automatically. This talk will review the advisories, the variations in wording and the public response and compare this with social science research about successful crisis communication, to create recommendations for future advisories</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2011/3089/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2011/3089/"><span>Groundwater quality in the Monterey Bay and Salinas <span class="hlt">Valley</span> groundwater basins, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kulongoski, Justin T.; Belitz, Kenneth</p> <p>2011-01-01</p> <p>The Monterey-Salinas study unit is nearly 1,000 square miles and consists of the Santa Cruz Purisima Formation Highlands, Felton Area, Scotts <span class="hlt">Valley</span>, Soquel <span class="hlt">Valley</span>, West Santa Cruz Terrace, Salinas <span class="hlt">Valley</span>, Pajaro <span class="hlt">Valley</span>, and Carmel <span class="hlt">Valley</span> groundwater basins (<span class="hlt">California</span> Department of Water Resources, 2003; Kulongski and Belitz, 2011). These basins were grouped into four study areas based primarily on geography. Groundwater basins in the north were grouped into the Santa Cruz study area, and those to the south were grouped into the Monterey Bay, the Salinas <span class="hlt">Valley</span>, and the Paso Robles study areas (Kulongoski and others, 2007). The study unit has warm, dry summers and cool, moist winters. Average annual rainfall ranges from 31 inches in Santa Cruz in the north to 13 inches in Paso Robles in the south. The study areas are drained by several rivers and their principal tributaries: the Salinas, Pajaro, and Carmel Rivers, and San Lorenzo Creek. The Salinas <span class="hlt">Valley</span> is a large intermontane <span class="hlt">valley</span> that extends southeastward from Monterey Bay to Paso Robles. It has been filled, up to a thickness of 2,000 feet, with Tertiary and Quaternary marine and terrestrial sediments that overlie granitic basement. The Miocene-age Monterey Formation and Pliocene- to Pleistocene-age Paso Robles Formation, and Pleistocene to Holocene-age alluvium contain freshwater used for supply. The primary aquifers in the study unit are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the <span class="hlt">California</span> Department of Public Health database. Public-supply wells are typically drilled to depths of 200 to 650 feet, consist of solid casing from the land surface to depths of about 175 to 500 feet, and are perforated below the solid casing. Water quality in the primary aquifers may differ from that in the shallower and deeper parts of the aquifer system. Groundwater movement is generally from the southern part of the Salinas <span class="hlt">Valley</span> north towards the Monterey Bay</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70018229','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70018229"><span>Three-dimensional simulations of ground motions in the San Bernardino <span class="hlt">Valley</span>, <span class="hlt">California</span>, for hypothetical <span class="hlt">earthquakes</span> on the San Andreas Fault</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Frankel, A.</p> <p>1993-01-01</p> <p>Three-dimensional finite difference simulations of elastic waves in the San Bernardino <span class="hlt">Valley</span> were performed for two hypothetical <span class="hlt">earthquakes</span> on the San Andreas fault: a point source with moment magnitude M5 and an extended rupture with M6.5. A method is presented for incorporating a source with arbitrary focal mechanism in the grid. Synthetics from the 3-D simulations are compared with those derived from 2-D (vertical cross section) and 1-D (flat-layered) models. The synthetic seismograms from the 3-D and 2-D simulations exhibit large surface waves produced by conversion of incident S waves at the edge of the basin. Seismograms from the flat-layered model do not contain these converted surface waves and underestimate the duration of shaking. Maps of maximum ground velocities occur in localized portions of the basin. The location of the largest velocities changes with the rupture propagation direction. Contours of maximum shaking are also dependent on asperity positions and radiation pattern. -from Author</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70189777','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70189777"><span>Late Holocene slip rate and ages of prehistoric <span class="hlt">earthquakes</span> along the Maacama Fault near Willits, Mendocino County, northern <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Prentice, Carol S.; Larsen, Martin C.; Kelsey, Harvey M.; Zachariasen, Judith</p> <p>2014-01-01</p> <p>The Maacama fault is the northward continuation of the Hayward–Rodgers Creek fault system and creeps at a rate of 5.7±0.1  mm/yr (averaged over the last 20 years) in Willits, <span class="hlt">California</span>. Our paleoseismic studies at Haehl Creek suggest that the Maacama fault has produced infrequent large <span class="hlt">earthquakes</span> in addition to creep. Fault terminations observed in several excavations provide evidence that a prehistoric surface‐rupturing <span class="hlt">earthquake</span> occurred between 1060 and 1180 calibrated years (cal) B.P. at the Haehl Creek site. A folding event, which we attribute to a more recent large <span class="hlt">earthquake</span>, occurred between 790 and 1060 cal B.P. In the last 560–690 years, a buried channel deposit has been offset 4.6±0.2  m, giving an average slip rate of 6.4–8.6  mm/yr, which is higher than the creep rate over the last 20 years. The difference between this slip rate and the creep rate suggests that coseismic slip up to 1.7 m could have occurred after the formation of the channel deposit and could be due to a paleoearthquake known from paleoseismic studies in the Ukiah <span class="hlt">Valley</span>, about 25 km to the southeast. Therefore, we infer that at least two, and possibly three, large <span class="hlt">earthquakes</span> have occurred at the Haehl Creek site since 1180 cal B.P. (770 C.E.), consistent with earlier studies suggesting infrequent, large <span class="hlt">earthquakes</span> on the Maacama fault. The short‐term geodetic slip rate across the Maacama fault zone is approximately twice the slip rate that we have documented at the Haehl Creek site, which is averaged over the last approximately 600 years. If the geodetic rate represents the long‐term slip accumulation across the fault zone, then we infer that, in the last ∼1200 years, additional <span class="hlt">earthquakes</span> may have occurred either on the Haehl Creek segment of the Maacama fault or on other active faults within the Maacama fault zone at this latitude.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70034408','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70034408"><span>Superficial simplicity of the 2010 El Mayorg-Cucapah <span class="hlt">earthquake</span> of Baja <span class="hlt">California</span> in Mexico</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wei, S.; Fielding, E.; Leprince, S.; Sladen, A.; Avouac, J.-P.; Helmberger, D.; Hauksson, E.; Chu, R.; Simons, M.; Hudnut, K.; Herring, T.; Briggs, R.</p> <p>2011-01-01</p> <p>The geometry of faults is usually thought to be more complicated at the surface than at depth and to control the initiation, propagation and arrest of seismic ruptures1-6. The fault system that runs from southern <span class="hlt">California</span> into Mexico is a simple strike-slip boundary: the west side of <span class="hlt">California</span> and Mexico moves northwards with respect to the east. However, the Mw 7.2 2010 El Mayorg-Cucapah <span class="hlt">earthquake</span> on this fault system produced a pattern of seismic waves that indicates a far more complex source than slip on a planar strike-slip fault. Here we use geodetic, remote-sensing and seismological data to reconstruct the fault geometry and history of slip during this <span class="hlt">earthquake</span>. We find that the <span class="hlt">earthquake</span> produced a straight 120-km-long fault trace that cut through the Cucapah mountain range and across the Colorado River delta. However, at depth, the fault is made up of two different segments connected by a small extensional fault. Both segments strike N130 ??E, but dip in opposite directions. The <span class="hlt">earthquake</span> was initiated on the connecting extensional fault and 15s later ruptured the two main segments with dominantly strike-slip motion. We show that complexities in the fault geometry at depth explain well the complex pattern of radiated seismic waves. We conclude that the location and detailed characteristics of the <span class="hlt">earthquake</span> could not have been anticipated on the basis of observations of surface geology alone. ?? 2011 Macmillan Publishers Limited. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.bssaonline.org/content/84/3/835.abstract','USGSPUBS'); return false;" href="http://www.bssaonline.org/content/84/3/835.abstract"><span>Triggered seismicity and deformation between the Landers, <span class="hlt">California</span>, and Little Skull Mountain, Nevada, <span class="hlt">earthquakes</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bodin, Paul; Gomberg, Joan</p> <p>1994-01-01</p> <p>This article presents evidence for the channeling of strain energy released by the Ms = 7.4 Landers, <span class="hlt">California</span>, <span class="hlt">earthquake</span> within the eastern <span class="hlt">California</span> shear zone (ECSZ). We document an increase in seismicity levels during the 22-hr period starting with the Landers <span class="hlt">earthquake</span> and culminating 22 hr later with the Ms = 5.4 Little Skull Mountain (LSM), Nevada, <span class="hlt">earthquake</span>. We evaluate the completeness of regional seismicity catalogs during this period and find that the continuity of post-Landers strain release within the ECSZ is even more pronounced than is evident from the catalog data. We hypothesize that regional-scale connectivity of faults within the ECSZ and LSM region is a critical ingredient in the unprecedented scale and distribution of remotely triggered <span class="hlt">earthquakes</span> and geodetically manifest strain changes that followed the Landers <span class="hlt">earthquake</span>. The viability of static strain changes as triggering agents is tested using numerical models. Modeling results illustrate that regional-scale fault connectivity can increase the static strain changes by approximately an order of magnitude at distances of at least 280 km, the distance between the Landers and LSM epicenters. This is possible for models that include both a network of connected faults that slip “sympathetically” and realistic levels of tectonic prestrain. Alternatively, if dynamic strains are a more significant triggering agent than static strains, ECSZ structure may still be important in determining the distribution of triggered seismic and aseismic deformation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160012760','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160012760"><span>Drought Impacts on Agricultural Production and Land Fallowing in <span class="hlt">California</span>'s Central <span class="hlt">Valley</span> in 2015</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rosevelt, Carolyn; Melton, Forrest S.; Johnson, Lee; Guzman, Alberto; Verdin, James P.; Thenkabail, Prasad S.; Mueller, Rick; Jones, Jeanine; Willis, Patrick</p> <p>2016-01-01</p> <p>The ongoing drought in <span class="hlt">California</span> substantially reduced surface water supplies for millions of acres of irrigated farmland in <span class="hlt">California</span>'s Central <span class="hlt">Valley</span>. Rapid assessment of drought impacts on agricultural production can aid water managers in assessing mitigation options, and guide decision making with respect to mitigation of drought impacts. Satellite remote sensing offers an efficient way to provide quantitative assessments of drought impacts on agricultural production and increases in fallow acreage associated with reductions in water supply. A key advantage of satellite-based assessments is that they can provide a measure of land fallowing that is consistent across both space and time. We describe an approach for monthly and seasonal mapping of uncultivated agricultural acreage developed as part of a joint effort by USGS, USDA, NASA, and the <span class="hlt">California</span> Department of Water Resources to provide timely assessments of land fallowing during drought events. This effort has used the Central <span class="hlt">Valley</span> of <span class="hlt">California</span> as a pilot region for development and testing of an operational approach. To provide quantitative measures of uncultivated agricultural acreage from satellite data early in the season, we developed a decision tree algorithm and applied it to time-series data from Landsat TM (Thematic Mapper), ETM+ (Enhanced Thematic Mapper Plus), OLI (Operational Land Imager), and MODIS (Moderate Resolution Imaging Spectroradiometer). Our effort has been focused on development of indicators of drought impacts in the March-August timeframe based on measures of crop development patterns relative to a reference period with average or above average rainfall. To assess the accuracy of the algorithms, monthly ground validation surveys were conducted across 650 fields from March-September in 2014 and 2015. We present the algorithm along with updated results from the accuracy assessment, and data and maps of land fallowing in the Central <span class="hlt">Valley</span> in 2015.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H53G1749R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H53G1749R"><span>Drought Impacts on Agricultural Production and Land Fallowing in <span class="hlt">California</span>'s Central <span class="hlt">Valley</span> in 2015</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rosevelt, C.; Melton, F. S.; Johnson, L.; Guzman, A.; Verdin, J. P.; Thenkabail, P. S.; Mueller, R.; Jones, J.; Willis, P.</p> <p>2015-12-01</p> <p>The ongoing drought in <span class="hlt">California</span> substantially reduced surface water supplies for millions of acres of irrigated farmland in <span class="hlt">California</span>'s Central <span class="hlt">Valley</span>. Rapid assessment of drought impacts on agricultural production can aid water managers in assessing mitigation options, and guide decision making with respect to mitigation of drought impacts. Satellite remote sensing offers an efficient way to provide quantitative assessments of drought impacts on agricultural production and increases in fallow acreage associated with reductions in water supply. A key advantage of satellite-based assessments is that they can provide a measure of land fallowing that is consistent across both space and time. We describe an approach for monthly and seasonal mapping of uncultivated agricultural acreage developed as part of a joint effort by USGS, USDA, NASA, and the <span class="hlt">California</span> Department of Water Resources to provide timely assessments of land fallowing during drought events. This effort has used the Central <span class="hlt">Valley</span> of <span class="hlt">California</span> as a pilot region for development and testing of an operational approach. To provide quantitative measures of uncultivated agricultural acreage from satellite data early in the season, we developed a decision tree algorithm and applied it to timeseries of data from Landsat TM, ETM+, OLI, and MODIS. Our effort has been focused on development of indicators of drought impacts in the March - August timeframe based on measures of crop development patterns relative to a reference period with average or above average rainfall. To assess the accuracy of the algorithms, monthly ground validation surveys were conducted across 650 fields from March - September in 2014 and 2015. We present the algorithm along with updated results from the accuracy assessment, and data and maps of land fallowing in the Central <span class="hlt">Valley</span> in 2015.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/1994/4208/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/1994/4208/report.pdf"><span>Land use and water use in the Antelope <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Templin, William E.; Phillips, Steven P.; Cherry, Daniel E.; DeBortoli, Myrna L.; Haltom, T.C.; McPherson, Kelly R.; Mrozek, C.A.</p> <p>1995-01-01</p> <p>Urban land use and water use in the Antelope <span class="hlt">Valley</span>, <span class="hlt">California</span>, have increased significantly since development of the <span class="hlt">valley</span> began in the late 1800's.. Ground water has been a major source of water in this area because of limited local surface-water resources. Ground-water pumpage is reported to have increased from about 29,000 acre-feet in 1919 to about 400,000 acre-feet in the 1950's. Completion of the <span class="hlt">California</span> Aqueduct to this area in the early 1970's conveyed water from the Sacramento-San Joaquin Delta, about 400 miles to the north. Declines in groundwater levels and increased costs of electrical power in the 1970's resulted in a reduction in the quantity of ground water that was pumped annually for irrigation uses. Total annual reported ground-water pumpage decreased to a low of about 53,200 acre-feet in 1983 and increased to about 91,700 acre-feet in 1991 as a result of rapid urban development and the 1987-92 drought. This increased urban development, in combination with several years of drought, renewed concern about a possible return to extensive depletion of ground-water storage and increased land subsidence.Increased water demands are expected to continue as a result of increased urban development. Water-demand forecasts in 1980 for the Antelope <span class="hlt">Valley</span> indicated that total annual water demand by 2020 was expected to be about 250,000 acre-feet, with agricultural demand being about 65 percent of this total. In 1990, total water demand was projected to be about 175,000 acre-feet by 2010; however, agricultural water demand was expected to account for only 37 percent of the total demand. New and existing land- and water-use data were collected and compiled during 1992-93 to identify present and historical land and water uses. In 1993, preliminary forecasts for total water demand by 2010 ranged from about 127,500 to 329,000 acre-feet. These wide-ranging estimates indicate that forecasts can change with time as factors that affect water demand change and</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017WRR....53.5756M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017WRR....53.5756M"><span>Drought impacts to water footprints and virtual water transfers of the Central <span class="hlt">Valley</span> of <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marston, Landon; Konar, Megan</p> <p>2017-07-01</p> <p>The Central <span class="hlt">Valley</span> of <span class="hlt">California</span> is one of the most productive agricultural locations in the world, which is made possible by a complex and vast irrigation system. Beginning in 2012, <span class="hlt">California</span> endured one of the worst droughts in its history. Local impacts of the drought have been evaluated, but it is not yet well understood how the drought reverberated through the global food system. Here we quantify drought impacts to the water footprint (WF) of agricultural production and virtual water transfers (VWT) from the Central <span class="hlt">Valley</span> of <span class="hlt">California</span>. To do this, we utilize high-resolution spatial and temporal data sets and a crop model from predrought conditions (2011) through 3 years of exceptional drought (2012-2014). Despite a 12% reduction in harvested area, the WF of agricultural production in the Central <span class="hlt">Valley</span> increased by 3%. This was due to greater crop water requirements from higher temperatures and a shift to more water-intensive orchard and vine crops. The groundwater WF increased from 7.00 km3 in 2011 to 13.63 km3 in 2014, predominantly in the Tulare Basin. Transfers of food commodities declined by 1% during the drought, yet total VWT increased by 3% (0.51 km3). From 2011 to 2014, groundwater VWT increased by 3.42 km3, offsetting the 0.94 km3 reduction in green VWT and the 1.96 km3 decrease in surface VWT. During the drought, local and global consumers nearly doubled their reliance on the Central <span class="hlt">Valley</span> Aquifer. These results indicate that drought may strengthen the telecoupling between groundwater withdrawals and distant consumers of agricultural commodities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMPA51A1800L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMPA51A1800L"><span>Next-Level ShakeZoning for <span class="hlt">Earthquake</span> Hazard Definition in Nevada</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Louie, J. N.; Savran, W. H.; Flinchum, B. A.; Dudley, C.; Prina, N.; Pullammanappallil, S.; Pancha, A.</p> <p>2011-12-01</p> <p>We are developing "Next-Level ShakeZoning" procedures tailored for defining <span class="hlt">earthquake</span> hazards in Nevada. The current Federally sponsored tools- the USGS hazard maps and ShakeMap, and FEMA HAZUS- were developed as statistical summaries to match <span class="hlt">earthquake</span> data from <span class="hlt">California</span>, Japan, and Taiwan. The 2008 Wells and Mogul events in Nevada showed in particular that the generalized statistical approach taken by ShakeMap cannot match actual data on shaking from <span class="hlt">earthquakes</span> in the Intermountain West, even to first order. Next-Level ShakeZoning relies on physics and geology to define <span class="hlt">earthquake</span> shaking hazards, rather than statistics. It follows theoretical and computational developments made over the past 20 years, to capitalize on detailed and specific local data sets to more accurately model the propagation and amplification of <span class="hlt">earthquake</span> waves through the multiple geologic basins of the Intermountain West. Excellent new data sets are now available for Las Vegas <span class="hlt">Valley</span>. Clark County, Nevada has completed the nation's very first effort to map <span class="hlt">earthquake</span> hazard class systematically through an entire urban area using Optim's SeisOpt° ReMi technique, which was adapted for large-scale data collection. Using the new Parcel Map in computing shaking in the <span class="hlt">Valley</span> for scenario <span class="hlt">earthquakes</span> is crucial for obtaining realistic predictions of ground motions. In an educational element of the project, a dozen undergraduate students have been computing 50 separate <span class="hlt">earthquake</span> scenarios affecting Las Vegas <span class="hlt">Valley</span>, using the Next-Level ShakeZoning process. Despite affecting only the upper 30 meters, the Vs30 geotechnical shear-velocity from the Parcel Map shows clear effects on 3-d shaking predictions computed so far at frequencies from 0.1 Hz up to 1.0 Hz. The effect of the Parcel Map on even the 0.1-Hz waves is prominent even with the large mismatch of wavelength to geotechnical depths. Amplifications and de-amplifications affected by the Parcel Map exceed a factor of two, and are</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMNH23B..08D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMNH23B..08D"><span>The Redwood Coast Tsunami Work Group: Promoting <span class="hlt">Earthquake</span> and Tsunami Resilience on <span class="hlt">California</span>'s North Coast</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dengler, L. A.; Henderson, C.; Larkin, D.; Nicolini, T.; Ozaki, V.</p> <p>2014-12-01</p> <p>In historic times, Northern <span class="hlt">California</span> has suffered the greatest losses from tsunamis in the U.S. contiguous 48 states. 39 tsunamis have been recorded in the region since 1933, including five that caused damage. This paper describes the Redwood Coast Tsunami Work Group (RCTWG), an organization formed in 1996 to address the tsunami threat from both near and far sources. It includes representatives from government agencies, public, private and volunteer organizations, academic institutions, and individuals interested in working to reduce tsunami risk. The geographic isolation and absence of scientific agencies such as the USGS and CGS in the region, and relatively frequent occurrence of both <span class="hlt">earthquakes</span> and tsunami events has created a unique role for the RCTWG, with activities ranging from basic research to policy and education and outreach programs. Regional interest in tsunami issues began in the early 1990s when there was relatively little interest in tsunamis elsewhere in the state. As a result, the group pioneered tsunami messaging and outreach programs. Beginning in 2008, the RCTWG has partnered with the National Weather Service and the <span class="hlt">California</span> Office of Emergency Services in conducting the annual "live code" tsunami communications tests, the only area outside of Alaska to do so. In 2009, the RCTWG joined with the Southern <span class="hlt">California</span> <span class="hlt">Earthquake</span> Alliance and the Bay Area <span class="hlt">Earthquake</span> Alliance to form the <span class="hlt">Earthquake</span> Country Alliance to promote a coordinated and consistent approach to both <span class="hlt">earthquake</span> and tsunami preparedness throughout the state. The RCTWG has produced and promoted a variety of preparedness projects including hazard mapping and sign placement, an annual "<span class="hlt">Earthquake</span> - Tsunami Room" at County Fairs, public service announcements and print material, assisting in TsunamiReady community recognition, and facilitating numerous multi-agency, multidiscipline coordinated exercises, and community evacuation drills. Nine assessment surveys from 1993 to 2013</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.6918P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.6918P"><span>The 2014 Napa <span class="hlt">valley</span> <span class="hlt">earthquake</span> constrained by InSAR and GNSS observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Polcari, Marco; Fernández, José; Palano, Mimmo; Albano, Matteo; Samsonov, Sergey; Stramondo, Salvatore; Zerbini, Susanna</p> <p>2015-04-01</p> <p>In this work InSAR and GNSS data have been exploited to evaluate the 3D displacement field produced by the Mw 6.0 <span class="hlt">earthquake</span> occurred on August 24th, 2014, southwest of Napa <span class="hlt">Valley</span>, <span class="hlt">California</span>. The <span class="hlt">earthquake</span> epicenter is located within the San Andreas Fault system, which forms the boundary between the North American and Pacific plates. As the Pacific plate moves to the northwest, relative to North America, deformation occurs between the major faults in the System. The InSAR data are those of the Sentinel-1 satellite recently launched on April 3rd, 2014. This satellite is capable of acquiring data in several modes such as Interferometric Wide (IW), Extra Wide (EW) swath mode or the Stripmap mode, thus varying area coverage and pixel resolution. Here a pair of SAR images, acquired in Stripmap mode with an incidence angle of about 23° and a pixel resolution of about 4 meters in both directions, covering an area of 70x180 Km have been used. The pre- and post-<span class="hlt">earthquake</span> images have been acquired on August 7th and August 31st, 2014 respectively. They are characterized by a perpendicular baseline of 2 meters and have been cut around the epicenter and multi-looked by a factor of 15x15 in range and azimuth to obtain a pixel size of about 60x60 m. The Digital Elevation Model (DEM) provided by the SRTM mission has been used to remove the topographic phase. Moreover, the Goldstein filtering and the Minimum Cost Flow (MCF) phase unwrapping algorithm were also applied. The analyzed GNSS dataset, spanning the 1st August 2014 - 2nd September 2014 period, includes 32 stations belonging to the Bay Area Regional Deformation Network and 301 additional continuous stations available from the UNAVCO and the CDDIS archives. The whole network of stations has been organized into seven sub-networks of about 50 sites each. The sub-networks were processed sharing a number of common sites to provide the necessary ties between them. The results of this processing step are daily estimates of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19900012177','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19900012177"><span>Age constraints for the present fault configuration in the Imperial <span class="hlt">Valley</span>, <span class="hlt">California</span>: Evidence for northwestward propagation of the Gulf of <span class="hlt">California</span> rift system</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Larsen, Shawn; Reilinger, Robert</p> <p>1990-01-01</p> <p>Releveling and other geophysical data for the Imperial <span class="hlt">Valley</span> of southern <span class="hlt">California</span> suggest the northern section of the Imperial-Brawley fault system, which includes the Mesquite Basin and Brawley Seismic Zone, is much younger than the 4 to 5 million year age of the <span class="hlt">valley</span> itself. A minimum age of 3000 years is calculated for the northern segment of the Imperial fault from correlations between surface topography and geodetically observed seismic/interseismic vertical movements. Calculations of a maximum age of 80,000 years is based upon displacements in the crystalline basement along the Imperial fault, inferred from seismic refraction surveys. This young age supports recent interpretations of heat flow measurements, which also suggest that the current patterns of seismicity and faults in the Imperial <span class="hlt">Valley</span> are not long lived. The current fault geometry and basement morphology suggest northwestward growth of the Imperial fault and migration of the Brawley Seismic Zone. It is suggested that this migration is a manifestation of the propagation of the Gulf of <span class="hlt">California</span> rift system into the North American continent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70035188','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70035188"><span>Potential <span class="hlt">earthquake</span> faults offshore Southern <span class="hlt">California</span>, from the eastern Santa Barbara Channel south to Dana Point</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fisher, M.A.; Sorlien, C.C.; Sliter, R.W.</p> <p>2009-01-01</p> <p>Urban areas in Southern <span class="hlt">California</span> are at risk from major <span class="hlt">earthquakes</span>, not only quakes generated by long-recognized onshore faults but also ones that occur along poorly understood offshore faults. We summarize recent research findings concerning these lesser known faults. Research by the U.S. Geological Survey during the past five years indicates that these faults from the eastern Santa Barbara Channel south to Dana Point pose a potential <span class="hlt">earthquake</span> threat. Historical seismicity in this area indicates that, in general, offshore faults can unleash <span class="hlt">earthquakes</span> having at least moderate (M 5-6) magnitude. Estimating the <span class="hlt">earthquake</span> hazard in Southern <span class="hlt">California</span> is complicated by strain partitioning and by inheritance of structures from early tectonic episodes. The three main episodes are Mesozoic through early Miocene subduction, early Miocene crustal extension coeval with rotation of the Western Transverse Ranges, and Pliocene and younger transpression related to plate-boundary motion along the San Andreas Fault. Additional complication in the analysis of <span class="hlt">earthquake</span> hazards derives from the partitioning of tectonic strain into strike-slip and thrust components along separate but kinematically related faults. The eastern Santa Barbara Basin is deformed by large active reverse and thrust faults, and this area appears to be underlain regionally by the north-dipping Channel Islands thrust fault. These faults could produce moderate to strong <span class="hlt">earthquakes</span> and destructive tsunamis. On the Malibu coast, <span class="hlt">earthquakes</span> along offshore faults could have left-lateral-oblique focal mechanisms, and the Santa Monica Mountains thrust fault, which underlies the oblique faults, could give rise to large (M ??7) <span class="hlt">earthquakes</span>. Offshore faults near Santa Monica Bay and the San Pedro shelf are likely to produce both strike-slip and thrust <span class="hlt">earthquakes</span> along northwest-striking faults. In all areas, transverse structures, such as lateral ramps and tear faults, which crosscut the main faults, could</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.T41C0633A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.T41C0633A"><span>Shallow Crustal Structure in the Northern Salton Trough, <span class="hlt">California</span>: Insights from a Detailed 3-D Velocity Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ajala, R.; Persaud, P.; Stock, J. M.; Fuis, G. S.; Hole, J. A.; Goldman, M.; Scheirer, D. S.</p> <p>2017-12-01</p> <p>The Coachella <span class="hlt">Valley</span> is the northern extent of the Gulf of <span class="hlt">California</span>-Salton Trough. It contains the southernmost segment of the San Andreas Fault (SAF) for which a magnitude 7.8 <span class="hlt">earthquake</span> rupture was modeled to help produce <span class="hlt">earthquake</span> planning scenarios. However, discrepancies in ground motion and travel-time estimates from the current Southern <span class="hlt">California</span> <span class="hlt">Earthquake</span> Center (SCEC) velocity model of the Salton Trough highlight inaccuracies in its shallow velocity structure. An improved 3-D velocity model that better defines the shallow basin structure and enables the more accurate location of <span class="hlt">earthquakes</span> and identification of faults is therefore essential for seismic hazard studies in this area. We used recordings of 126 explosive shots from the 2011 Salton Seismic Imaging Project (SSIP) to SSIP receivers and Southern <span class="hlt">California</span> Seismic Network (SCSN) stations. A set of 48,105 P-wave travel time picks constituted the highest-quality input to a 3-D tomographic velocity inversion. To improve the ray coverage, we added network-determined first arrivals at SCSN stations from 39,998 recently relocated local <span class="hlt">earthquakes</span>, selected to a maximum focal depth of 10 km, to develop a detailed 3-D P-wave velocity model for the Coachella <span class="hlt">Valley</span> with 1-km grid spacing. Our velocity model shows good resolution ( 50 rays/cubic km) down to a minimum depth of 7 km. Depth slices from the velocity model reveal several interesting features. At shallow depths ( 3 km), we observe an elongated trough of low velocity, attributed to sediments, located subparallel to and a few km SW of the SAF, and a general velocity structure that mimics the surface geology of the area. The persistence of the low-velocity sediments to 5-km depth just north of the Salton Sea suggests that the underlying basement surface, shallower to the NW, dips SE, consistent with interpretation from gravity studies (Langenheim et al., 2005). On the western side of the Coachella <span class="hlt">Valley</span>, we detect depth-restricted regions of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/28408','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/28408"><span>Wildlife Diversity in <span class="hlt">Valley</span>-Foothill Riparian Habitat: North Central vs. Central Coast <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>William D. Tietje; Reginald H. Barrett; Eric B. Kleinfelter; Brett T. Carré</p> <p>1991-01-01</p> <p>Habitat characteristics and diversity of terrestrial vertebrates were studied September 1989 to August 1990 in <span class="hlt">valley</span>-foothill riparian habitat on two study areas: Dye Creek, Tehama County, and Avenales Ranch, San Luis Obispo County, <span class="hlt">California</span>. The assumption considered was that differences between study areas in physical and vegetation characteristics would be...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750012770','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750012770"><span>Measuring ground movement in geothermal areas of Imperial <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lofgren, B. E.</p> <p>1974-01-01</p> <p>Significant ground movement may accompany the extraction of large quantities of fluids from the subsurface. In Imperial <span class="hlt">Valley</span>, <span class="hlt">California</span>, one of the potential hazards of geothermal development is the threat of both subsidence and horizontal movement of the land surface. Regional and local survey nets are being monitored to detect and measure possible ground movement caused by future geothermal developments. Precise measurement of surface and subsurface changes will be required to differentiate man-induced changes from natural processes in this tectonically active region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70188535','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70188535"><span>Tomographic Rayleigh-wave group velocities in the Central <span class="hlt">Valley</span>, <span class="hlt">California</span> centered on the Sacramento/San Joaquin Delta</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fletcher, Jon Peter B.; Erdem, Jemile; Seats, Kevin; Lawrence, Jesse</p> <p>2016-01-01</p> <p>If shaking from a local or regional <span class="hlt">earthquake</span> in the San Francisco Bay region were to rupture levees in the Sacramento/San Joaquin Delta then brackish water from San Francisco Bay would contaminate the water in the Delta: the source of fresh water for about half of <span class="hlt">California</span>. As a prelude to a full shear-wave velocity model that can be used in computer simulations and further seismic hazard analysis, we report on the use of ambient noise tomography to build a fundamental-mode, Rayleigh-wave group velocity model for the region around the Sacramento/San Joaquin Delta in the western Central <span class="hlt">Valley</span>, <span class="hlt">California</span>. Recordings from the vertical component of about 31 stations were processed to compute the spatial distribution of Rayleigh wave group velocities. Complex coherency between pairs of stations were stacked over 8 months to more than a year. Dispersion curves were determined from 4 to about 18 seconds. We calculated average group velocities for each period and inverted for deviations from the average for a matrix of cells that covered the study area. Smoothing using the first difference is applied. Cells of the model were about 5.6 km in either dimension. Checkerboard tests of resolution, which is dependent on station density, suggest that the resolving ability of the array is reasonably good within the middle of the array with resolution between 0.2 and 0.4 degrees. Overall, low velocities in the middle of each image reflect the deeper sedimentary syncline in the Central <span class="hlt">Valley</span>. In detail, the model shows several centers of low velocity that may be associated with gross geologic features such as faulting along the western margin of the Central <span class="hlt">Valley</span>, oil and gas reservoirs, and large cross cutting features like the Stockton arch. At shorter periods around 5.5s, the model’s western boundary between low and high velocities closely follows regional fault geometry and the edge of a residual isostatic gravity low. In the eastern part of the <span class="hlt">valley</span>, the boundaries</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRB..121.2429F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRB..121.2429F"><span>Tomographic Rayleigh wave group velocities in the Central <span class="hlt">Valley</span>, <span class="hlt">California</span>, centered on the Sacramento/San Joaquin Delta</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fletcher, Jon B.; Erdem, Jemile; Seats, Kevin; Lawrence, Jesse</p> <p>2016-04-01</p> <p>If shaking from a local or regional <span class="hlt">earthquake</span> in the San Francisco Bay region were to rupture levees in the Sacramento/San Joaquin Delta, then brackish water from San Francisco Bay would contaminate the water in the Delta: the source of freshwater for about half of <span class="hlt">California</span>. As a prelude to a full shear-wave velocity model that can be used in computer simulations and further seismic hazard analysis, we report on the use of ambient noise tomography to build a fundamental mode, Rayleigh wave group velocity model for the region around the Sacramento/San Joaquin Delta in the western Central <span class="hlt">Valley</span>, <span class="hlt">California</span>. Recordings from the vertical component of about 31 stations were processed to compute the spatial distribution of Rayleigh wave group velocities. Complex coherency between pairs of stations was stacked over 8 months to more than a year. Dispersion curves were determined from 4 to about 18 s. We calculated average group velocities for each period and inverted for deviations from the average for a matrix of cells that covered the study area. Smoothing using the first difference is applied. Cells of the model were about 5.6 km in either dimension. Checkerboard tests of resolution, which are dependent on station density, suggest that the resolving ability of the array is reasonably good within the middle of the array with resolution between 0.2 and 0.4°. Overall, low velocities in the middle of each image reflect the deeper sedimentary syncline in the Central <span class="hlt">Valley</span>. In detail, the model shows several centers of low velocity that may be associated with gross geologic features such as faulting along the western margin of the Central <span class="hlt">Valley</span>, oil and gas reservoirs, and large crosscutting features like the Stockton arch. At shorter periods around 5.5 s, the model's western boundary between low and high velocities closely follows regional fault geometry and the edge of a residual isostatic gravity low. In the eastern part of the <span class="hlt">valley</span>, the boundaries of the low</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/677055','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/677055"><span>Winnetka deformation zone: Surface expression of coactive slip on a blind fault during the Northridge <span class="hlt">earthquake</span> sequence, <span class="hlt">California</span>. Evidence that coactive faulting occurred in the Canoga Park, Winnetka, and Northridge areas during the 17 January 1994, Northridge, <span class="hlt">California</span> <span class="hlt">earthquake</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Cruikshank, K.M.; Johnson, A.M.; Fleming, R.W.</p> <p>1996-12-31</p> <p>Measurements of normalized length changes of streets over an area of 9 km{sup 2} in San Fernando <span class="hlt">Valley</span> of Los Angeles, <span class="hlt">California</span>, define a distinctive strain pattern that may well reflect blind faulting during the 1994 Northridge <span class="hlt">earthquake</span>. Strain magnitudes are about 3 {times} 10{sup {minus}4}, locally 10{sup {minus}3}. They define a deformation zone trending diagonally from near Canoga Park in the southwest, through Winnetka, to near Northridge in the northeast. The deformation zone is about 4.5 km long and 1 km wide. The northwestern two-thirds of the zone is a belt of extension of streets, and the southeastern one-thirdmore » is a belt of shortening of streets. On the northwest and southeast sides of the deformation zone the magnitude of the strains is too small to measure, less than 10{sup {minus}4}. Complete states of strain measured in the northeastern half of the deformation zone show that the directions of principal strains are parallel and normal to the walls of the zone, so the zone is not a strike-slip zone. The magnitudes of strains measured in the northeastern part of the Winnetka area were large enough to fracture concrete and soils, and the area of larger strains correlates with the area of greater damage to such roads and sidewalks. All parts of the pattern suggest a blind fault at depth, most likely a reverse fault dipping northwest but possibly a normal fault dipping southeast. The magnitudes of the strains in the Winnetka area are consistent with the strains produced at the ground surface by a blind fault plane extending to depth on the order of 2 km and a net slip on the order of 1 m, within a distance of about 100 to 500 m of the ground surface. The pattern of damage in the San Fernando <span class="hlt">Valley</span> suggests a fault segment much longer than the 4.5 km defined by survey data in the Winnetka area. The blind fault segment may extend several kilometers in both directions beyond the Winnetka area. This study of the Winnetka area further supports</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2001/0408/pdf/of01-408.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2001/0408/pdf/of01-408.pdf"><span>Report for borehole explosion data acquired in the 1999 Los Angeles Region Seismic Experiment (LARSE II), Southern <span class="hlt">California</span>: Part I, description of the survey</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fuis, Gary S.; Murphy, Janice M.; Okaya, David A.; Clayton, Robert W.; Davis, Paul M.; Thygesen, Kristina; Baher, Shirley A.; Ryberg, Trond; Benthien, Mark L.; Simila, Gerry; Perron, J. Taylor; Yong, Alan K.; Reusser, Luke; Lutter, William J.; Kaip, Galen; Fort, Michael D.; Asudeh, Isa; Sell, Russell; Van Schaack, John R.; Criley, Edward E.; Kaderabek, Ronald; Kohler, Will M.; Magnuski, Nickolas H.</p> <p>2001-01-01</p> <p>The Los Angeles Region Seismic Experiment (LARSE) is a joint project of the U.S. Geological Survey (USGS) and the Southern <span class="hlt">California</span> <span class="hlt">Earthquake</span> Center (SCEC). The purpose of this project is to produce seismic images of the subsurface of the Los Angeles region down to the depths at which <span class="hlt">earthquakes</span> occur, and deeper, in order to remedy a deficit in our knowledge of the deep structure of this region. This deficit in knowledge has persisted despite over a century of oil exploration and nearly 70 years of recording <span class="hlt">earthquakes</span> in southern <span class="hlt">California</span>. Understanding the deep crustal structure and tectonics of southern <span class="hlt">California</span> is important to <span class="hlt">earthquake</span> hazard assessment. Specific imaging targets of LARSE include (a) faults, especially blind thrust faults, which cannot be reliably detected any other way; and (b) the depths and configurations of sedimentary basins. Imaging of faults is important in both <span class="hlt">earthquake</span> hazard assessment but also in modeling <span class="hlt">earthquake</span> occurrence. <span class="hlt">Earthquake</span> occurrence cannot be understood unless the <span class="hlt">earthquake</span>-producing "machinery" (tectonics) is known (Fuis and others, 2001). Imaging the depths and configurations of sedimentary basins is important because <span class="hlt">earthquake</span> shaking at the surface is enhanced by basin depth and by the presence of sharp basin edges (Wald and Graves, 1998, Working Group on <span class="hlt">California</span> <span class="hlt">Earthquake</span> Probabilities, 1995; Field and others, 2001). (Sedimentary basins are large former <span class="hlt">valleys</span> now filled with sediment eroded from nearby mountains.) Sedimentary basins in the Los Angeles region that have been investigated by LARSE include the Los Angeles, San Gabriel <span class="hlt">Valley</span>, San Fernando <span class="hlt">Valley</span>, and Santa Clarita <span class="hlt">Valley</span> basins. The seismic imaging surveys of LARSE include recording of <span class="hlt">earthquakes</span> (both local and distant <span class="hlt">earthquakes</span>) along several corridors (or transects) through the Los Angeles region and also recording of man-made sources along these same corridors. Man-made sources have included airguns offshore and borehole</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70017949','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70017949"><span>An episode of reinflation of the Long <span class="hlt">Valley</span> Caldera, eastern <span class="hlt">California</span>: 1989-1991</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Langbein, J.; Hill, D.P.; Parker, T.N.; Wilkinson, S.K.</p> <p>1993-01-01</p> <p>Following the episodes of inflation of the resurgent dome associated with the May 1980 <span class="hlt">earthquake</span> sequence (four M 6 <span class="hlt">earthquakes</span>) and the January 1983 <span class="hlt">earthquake</span> swarm (two M 5.2 events), 7 years of frequently repeated two-color geodimeter measurements spanning the Long <span class="hlt">Valley</span> caldera document gradually decreasing extensional strain rates from 5 ppm/yr in mid-1983, when the measurements began, to near zero in mid-1989. Early October 1989 marked a change in activity when measurements of the two-color geodimeter network showed a significant increase in extensional strain rate (9 ppm/yr) across the caldera. The seismic activity began exceeding 10 M ??? 1..2 per week in early December 1989 and rapidly increased to a sustained level of tens of M ??? 1.2 per week with bursts having hundreds of events per day. The episode of inflation can be modeled by a single Mogi point source located about 7 km beneath the center of the resurgent dome. -from Authors</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMEP43A0828O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMEP43A0828O"><span>Coho Salmon Habitat in a Changing Environment-Green <span class="hlt">Valley</span> Creek, Graton, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>O'Connor, M. D.; Kobor, J. S.; Sherwood, M. N.</p> <p>2013-12-01</p> <p>Green <span class="hlt">Valley</span> Creek (GVC) is a small (101 sq km) aquatic habitat refugium in the Russian River watershed (3,840 sq km) in coastal northern <span class="hlt">California</span>. Coho salmon (Onchorhynchus kisutch) is endangered per the Federal Endangered Species Act, and GVC is one stream where coho have persisted. Fish surveys in GVC have found high species diversity, growth rates, and over-summer survival. The upper portion of GVC comprises a principal tributary (20 sq km) that provides spawning and rearing habitat for coho. The second principal tributary, Atascadero Creek, is comparable in size, but has few fish. Atascadero Creek and lower GVC have broad, densely vegetated floodplains. A Recovery Plan for the Central Coastal <span class="hlt">California</span> coho Evolutionarily Significant Unit has been developed by the National Marine Fisheries Service (NMFS), which applies to the Russian River and its tributaries. Cooperative research regarding fish populations and habitat, a captive breeding and release program for native coho salmon, and efforts to plan for and restore habitat are ongoing. These regional efforts are particularly active in GVC, and participants include NMFS, the <span class="hlt">California</span> Department of Fish and Wildlife, the Gold Ridge Resource Conservation District, the <span class="hlt">California</span> Coastal Conservancy, the University of <span class="hlt">California</span> Cooperative Extension, and the National Fish and Wildlife Foundation, among others. Our research focuses on hydrologic, geomorphic and hydrogeologic characteristics of the watershed in relation to aquatic habitat. Natural watershed factors contributing to habitat for coho include proximity to the coastal summer fog belt with cool temperatures, the Wilson Grove Formation aquifer that maintains dry season stream flow, and structural geology favorable for active floodplain morphology. Human impacts include water use and agriculture and rural residential development. Historic human impacts include stream clearing and draining of wetlands and floodplain for agriculture, which likely</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016HydJ...24..675F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016HydJ...24..675F"><span>Water availability and land subsidence in the Central <span class="hlt">Valley</span>, <span class="hlt">California</span>, USA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Faunt, Claudia C.; Sneed, Michelle; Traum, Jon; Brandt, Justin T.</p> <p>2016-05-01</p> <p>The Central <span class="hlt">Valley</span> in <span class="hlt">California</span> (USA) covers about 52,000 km2 and is one of the most productive agricultural regions in the world. This agriculture relies heavily on surface-water diversions and groundwater pumpage to meet irrigation water demand. Because the <span class="hlt">valley</span> is semi-arid and surface-water availability varies substantially, agriculture relies heavily on local groundwater. In the southern two thirds of the <span class="hlt">valley</span>, the San Joaquin <span class="hlt">Valley</span>, historic and recent groundwater pumpage has caused significant and extensive drawdowns, aquifer-system compaction and subsidence. During recent drought periods (2007-2009 and 2012-present), groundwater pumping has increased owing to a combination of decreased surface-water availability and land-use changes. Declining groundwater levels, approaching or surpassing historical low levels, have caused accelerated and renewed compaction and subsidence that likely is mostly permanent. The subsidence has caused operational, maintenance, and construction-design problems for water-delivery and flood-control canals in the San Joaquin <span class="hlt">Valley</span>. Planning for the effects of continued subsidence in the area is important for water agencies. As land use, managed aquifer recharge, and surface-water availability continue to vary, long-term groundwater-level and subsidence monitoring and modelling are critical to understanding the dynamics of historical and continued groundwater use resulting in additional water-level and groundwater storage declines, and associated subsidence. Modeling tools such as the Central <span class="hlt">Valley</span> Hydrologic Model, can be used in the evaluation of management strategies to mitigate adverse impacts due to subsidence while also optimizing water availability. This knowledge will be critical for successful implementation of recent legislation aimed toward sustainable groundwater use.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED355978.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED355978.pdf"><span>Communication/Culture Study for Victor <span class="hlt">Valley</span> College, Victorville, <span class="hlt">California</span>, November 1991-April 1992.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Caldwell, Patricia F.</p> <p></p> <p>In November 1991, a study was conducted to assess the corporate culture and state of communication at Victor <span class="hlt">Valley</span> College (VVC), in Victorville, <span class="hlt">California</span>. The study was designed to determine the extent to which "trust" or "distrust" existed at VVC, and whether the lack of communication on campus was real or perceived. Study…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70025926','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70025926"><span>An empirical model for <span class="hlt">earthquake</span> probabilities in the San Francisco Bay region, <span class="hlt">California</span>, 2002-2031</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Reasenberg, P.A.; Hanks, T.C.; Bakun, W.H.</p> <p>2003-01-01</p> <p>The moment magnitude M 7.8 <span class="hlt">earthquake</span> in 1906 profoundly changed the rate of seismic activity over much of northern <span class="hlt">California</span>. The low rate of seismic activity in the San Francisco Bay region (SFBR) since 1906, relative to that of the preceding 55 yr, is often explained as a stress-shadow effect of the 1906 <span class="hlt">earthquake</span>. However, existing elastic and visco-elastic models of stress change fail to fully account for the duration of the lowered rate of <span class="hlt">earthquake</span> activity. We use variations in the rate of <span class="hlt">earthquakes</span> as a basis for a simple empirical model for estimating the probability of M ≥6.7 <span class="hlt">earthquakes</span> in the SFBR. The model preserves the relative magnitude distribution of sources predicted by the Working Group on <span class="hlt">California</span> <span class="hlt">Earthquake</span> Probabilities' (WGCEP, 1999; WGCEP, 2002) model of characterized ruptures on SFBR faults and is consistent with the occurrence of the four M ≥6.7 <span class="hlt">earthquakes</span> in the region since 1838. When the empirical model is extrapolated 30 yr forward from 2002, it gives a probability of 0.42 for one or more M ≥6.7 in the SFBR. This result is lower than the probability of 0.5 estimated by WGCEP (1988), lower than the 30-yr Poisson probability of 0.60 obtained by WGCEP (1999) and WGCEP (2002), and lower than the 30-yr time-dependent probabilities of 0.67, 0.70, and 0.63 obtained by WGCEP (1990), WGCEP (1999), and WGCEP (2002), respectively, for the occurrence of one or more large <span class="hlt">earthquakes</span>. This lower probability is consistent with the lack of adequate accounting for the 1906 stress-shadow in these earlier reports. The empirical model represents one possible approach toward accounting for the stress-shadow effect of the 1906 <span class="hlt">earthquake</span>. However, the discrepancy between our result and those obtained with other modeling methods underscores the fact that the physics controlling the timing of <span class="hlt">earthquakes</span> is not well understood. Hence, we advise against using the empirical model alone (or any other single probability model) for estimating the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMNH13B1929M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMNH13B1929M"><span><span class="hlt">California</span>'s Vulnerability to Volcanic Hazards: What's at Risk?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mangan, M.; Wood, N. J.; Dinitz, L.</p> <p>2015-12-01</p> <p><span class="hlt">California</span> is a leader in comprehensive planning for devastating <span class="hlt">earthquakes</span>, landslides, floods, and tsunamis. Far less attention, however, has focused on the potentially devastating impact of volcanic eruptions, despite the fact that they occur in the State about as frequently as the largest <span class="hlt">earthquakes</span> on the San Andreas Fault Zone. At least 10 eruptions have occurred in the past 1,000 years—most recently in northern <span class="hlt">California</span> (Lassen Peak 1914 to 1917)—and future volcanic eruptions are inevitable. The likelihood of renewed volcanism in <span class="hlt">California</span> is about one in a few hundred to one in a few thousand annually. Eight young volcanoes, ranked as Moderate to Very High Threat [1] are dispersed throughout the State. Partially molten rock (magma) resides beneath at least seven of these—Medicine Lake Volcano, Mount Shasta, Lassen Volcanic Center, Clear Lake Volcanic Field, Long <span class="hlt">Valley</span> Volcanic Region, Coso Volcanic Field, and Salton Buttes— causing <span class="hlt">earthquakes</span>, toxic gas emissions, hydrothermal activity, and (or) ground deformation. Understanding the hazards and identifying what is at risk are the first steps in building community resilience to volcanic disasters. This study, prepared in collaboration with the State of <span class="hlt">California</span> Governor's Office of Emergency Management and the <span class="hlt">California</span> Geological Survey, provides a broad perspective on the State's exposure to volcano hazards by integrating mapped volcano hazard zones with geospatial data on at-risk populations, infrastructure, and resources. The study reveals that ~ 16 million acres fall within <span class="hlt">California</span>'s volcano hazard zones, along with ~ 190 thousand permanent and 22 million transitory populations. Additionally, far-field disruption to key water delivery systems, agriculture, utilities, and air traffic is likely. Further site- and sector-specific analyses will lead to improved hazard mitigation efforts and more effective disaster response and recovery. [1] "Volcanic Threat and Monitoring Capabilities</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA01809&hterms=deposit+alluvial&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddeposit%2Balluvial','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA01809&hterms=deposit+alluvial&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddeposit%2Balluvial"><span>Space Radar Image of Owens <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1999-01-01</p> <p>This is a three-dimensional perspective view of Owens <span class="hlt">Valley</span>, near the town of Bishop, <span class="hlt">California</span> that was created by combining two spaceborne radar images using a technique known as interferometry. Visualizations like this one are helpful to scientists because they clarify the relationships of the different types of surfaces detected by the radar and the shapes of the topographic features such as mountains and <span class="hlt">valleys</span>. The view is looking southeast along the eastern edge of Owens <span class="hlt">Valley</span>. The White Mountains are in the center of the image, and the Inyo Mountains loom in the background. The high peaks of the White Mountains rise more than 3,000 meters (10,000 feet) above the <span class="hlt">valley</span> floor. The runways of the Bishop airport are visible at the right edge of the image. The meandering course of the Owens River and its tributaries appear light blue on the <span class="hlt">valley</span> floor. Blue areas in the image are smooth, yellow areas are rock outcrops, and brown areas near the mountains are deposits of boulders, gravel and sand known as alluvial fans. The image was constructed by overlaying a color composite radar image on top of a digital elevation map. The radar data were taken by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on board the space shuttle Endeavour in October 1994. The digital elevation map was produced using radar interferometry, a process in which radar data are acquired on different passes of the space shuttle. The two data passes are compared to obtain elevation information. The elevation data were derived from a 1,500-km-long (930-mile) digital topographic map processed at JPL. Radar image data are draped over the topography to provide the color with the following assignments: red is L-band vertically transmitted, vertically received; green is C-band vertically transmitted, vertically received; and blue is the ratio of C-band vertically transmitted, vertically received to L-band vertically transmitted, vertically received. This image is</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/27987','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/27987"><span>A Test of the <span class="hlt">California</span> Wildlife-Habitat Relationship System for Breeding Birds in <span class="hlt">Valley</span>-Foothill Riparian Habitat</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Stephen A. Laymon</p> <p>1989-01-01</p> <p>The <span class="hlt">California</span> Wildlife-Habitat Relationship (WHR) system was tested for birds breeding in the <span class="hlt">Valley</span>-Foothill Riparian habitat along <span class="hlt">California</span>'s Sacramento and South Fork Kern rivers. The model performed poorly with 33 pct and 21 pct correct predictions respectively at the two locations. Changes to the model for 60 species on the Sacramento River and 66 species...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70014926','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70014926"><span>PERFORMANCE OF AN <span class="hlt">EARTHQUAKE</span> EXCITED ROOF DIAPHRAGM.</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Celebi, M.; Brady, G.; Safak, E.; Converse, A.; ,</p> <p>1986-01-01</p> <p>The objective of this paper is to study the <span class="hlt">earthquake</span> performance of the roof diaphragm of the West <span class="hlt">Valley</span> College gymnasium in Saratoga, <span class="hlt">California</span> through a complete set of acceleration records obtained during the 24 April 1984 Morgan Hill <span class="hlt">Earthquake</span> (M equals 6. 1). The roof diaphragm of the 112 ft. multiplied by 144 ft. rectangular, symmetric gymnasium consists of 3/8 in. plywood over tongue-and-groove sheathing attached to steel trusses supported by reinforced concrete columns and walls. Three sensors placed in the direction of each of the axes of the diaphragm facilitate the evaluation of in-plane deformation of the diaphragm. Other sensors placed at ground level measure vertical and horizontal motion of the building floor, and consequently allow the calculation of the relative motion of the diaphragm with respect to the ground level.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018GeoJI.tmp..178C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018GeoJI.tmp..178C"><span>Radiated Seismic Energy of <span class="hlt">Earthquakes</span> in the South-Central Region of the Gulf of <span class="hlt">California</span>, Mexico</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Castro, Raúl R.; Mendoza-Camberos, Antonio; Pérez-Vertti, Arturo</p> <p>2018-05-01</p> <p>We estimated the radiated seismic energy (ES) of 65 <span class="hlt">earthquakes</span> located in the south-central region of the Gulf of <span class="hlt">California</span>. Most of these events occurred along active transform faults that define the Pacific-North America plate boundary and have magnitudes between M3.3 and M5.9. We corrected the spectral records for attenuation using nonparametric S-wave attenuation functions determined with the whole data set. The path effects were isolated from the seismic source using a spectral inversion. We computed radiated seismic energy of the <span class="hlt">earthquakes</span> by integrating the square velocity source spectrum and estimated their apparent stresses. We found that most events have apparent stress between 3 × 10-4 and 3 MPa. Model independent estimates of the ratio between seismic energy and moment (ES/M0) indicates that this ratio is independent of <span class="hlt">earthquake</span> size. We conclude that in general the apparent stress is low (σa < 3 MPa) in the south-central and southern Gulf of <span class="hlt">California</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70027735','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70027735"><span>Miocene rapakivi granites in the southern Death <span class="hlt">Valley</span> region, <span class="hlt">California</span>, USA</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Calzia, J.P.; Ramo, O.T.</p> <p>2005-01-01</p> <p>Rapakivi granites in the southern Death <span class="hlt">Valley</span> region, <span class="hlt">California</span>, include the 12.4-Ma granite of Kingston Peak, the ca. 10.6-Ma Little Chief stock, and the 9.8-Ma Shoshone pluton. All of these granitic rocks are texturally zoned from a porphyritic rim facies, characterized by rapakivi textures and miarolitic cavities, to an equigranular aplite core. These granites crystallized from anhydrous and peraluminous to metaluminous magmas that were more oxidized and less alkalic than type rapakivi granites from southern Finland. Chemical and isotope (Nd-Sr-Pb) data suggest that rapakivi granites of the southern Death <span class="hlt">Valley</span> region were derived by partial melting of lower crustal rocks (possibly including Mesozoic plutonic component) with some mantle input as well; they were emplaced at shallow crustal levels (4 km) in an actively extending orogen.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70180922','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70180922"><span>Miocene rapakivi granites in the southern Death <span class="hlt">Valley</span> region, <span class="hlt">California</span>, USA</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Calzia, James P.; Ramo, O.T.</p> <p>2005-01-01</p> <p>Rapakivi granites in the southern Death <span class="hlt">Valley</span> region, <span class="hlt">California</span>, include the 12.4-Ma granite of Kingston Peak, the ca. 10.6-Ma Little Chief stock, and the 9.8-Ma Shoshone pluton. All of these granitic rocks are texturally zoned from a porphyritic rim facies, characterized by rapakivi textures and miarolitic cavities, to an equigranular aplite core. These granites crystallized from anhydrous and peraluminous to metaluminous magmas that were more oxidized and less alkalic than type rapakivi granites from southern Finland. Chemical and isotope (Nd–Sr–Pb) data suggest that rapakivi granites of the southern Death <span class="hlt">Valley</span> region were derived by partial melting of lower crustal rocks (possibly including Mesozoic plutonic component) with some mantle input as well; they were emplaced at shallow crustal levels (4 km) in an actively extending orogen.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.S31B2240M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.S31B2240M"><span>Three-Dimensional P-wave Velocity Structure Beneath Long <span class="hlt">Valley</span> Caldera, <span class="hlt">California</span>, Using Local-Regional Double-Difference Tomography</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Menendez, H. M.; Thurber, C. H.</p> <p>2011-12-01</p> <p>Eastern <span class="hlt">California</span>'s Long <span class="hlt">Valley</span> Caldera (LVC) and the Mono-Inyo Crater volcanic systems have been active for the past ~3.6 million years. Long <span class="hlt">Valley</span> is known to produce very large silicic eruptions, the last of which resulted in the formation of a 17 km by 32 km wide, east-west trending caldera. Relatively recent unrest began between 1978-1980 with five ML ≥ 5.7 non-double-couple (NDC) <span class="hlt">earthquakes</span> and associated aftershock swarms. Similar shallow seismic swarms have continued south of the resurgent dome and beneath Mammoth Mountain, surrounding sites of increased CO2 gas emissions. Nearly two decades of increased volcanic activity led to the 1997 installation of a temporary three-component array of 69 seismometers. This network, deployed by the Durham University, the USGS, and Duke University, recorded over 4,000 high-frequency events from May to September. A local tomographic inversion of 283 events surrounding Mammoth Mountain yielded a velocity structure with low Vp and Vp/Vs anomalies at 2-3 km bsl beneath the resurgent dome and Casa Diablo hot springs. These anomalies were interpreted to be CO2 reservoirs (Foulger et al., 2003). Several teleseismic and regional tomography studies have also imaged low Vp anomalies beneath the caldera at ~5-15 km depth, interpreted to be the underlying magma reservoir (Dawson et al., 1990; Weiland et al., 1995; Thurber et al., 2009). This study aims to improve the resolution of the LVC regional velocity model by performing tomographic inversions using the local events from 1997 in conjunction with regional events recorded by the Northern <span class="hlt">California</span> Seismic Network (NCSN) between 1980 and 2010 and available refraction data. Initial tomographic inversions reveal a low velocity zone at ~2 to 6 km depth beneath the caldera. This structure may simply represent the caldera fill. Further iterations and the incorporation of teleseismic data may better resolve the overall shape and size of the underlying magma reservoir.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.S41C0800X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.S41C0800X"><span>Frequency-Dependent Tidal Triggering of Low Frequency <span class="hlt">Earthquakes</span> Near Parkfield, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xue, L.; Burgmann, R.; Shelly, D. R.</p> <p>2017-12-01</p> <p>The effect of small periodic stress perturbations on <span class="hlt">earthquake</span> generation is not clear, however, the rate of low-frequency <span class="hlt">earthquakes</span> (LFEs) near Parkfield, <span class="hlt">California</span> has been found to be strongly correlated with solid earth tides. Laboratory experiments and theoretical analyses show that the period of imposed forcing and source properties affect the sensitivity to triggering and the phase relation of the peak seismicity rate and the periodic stress, but frequency-dependent triggering has not been quantitatively explored in the field. Tidal forcing acts over a wide range of frequencies, therefore the sensitivity to tidal triggering of LFEs provides a good probe to the physical mechanisms affecting <span class="hlt">earthquake</span> generation. In this study, we consider the tidal triggering of LFEs near Parkfield, <span class="hlt">California</span> since 2001. We find the LFEs rate is correlated with tidal shear stress, normal stress rate and shear stress rate. The occurrence of LFEs can also be independently modulated by groups of tidal constituents at semi-diurnal, diurnal and fortnightly frequencies. The strength of the response of LFEs to the different tidal constituents varies between LFE families. Each LFE family has an optimal triggering frequency, which does not appear to be depth dependent or systematically related to other known properties. This suggests the period of the applied forcing plays an important role in the triggering process, and the interaction of periods of loading history and source region properties, such as friction, effective normal stress and pore fluid pressure, produces the observed frequency-dependent tidal triggering of LFEs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2012-03-01/pdf/2012-4974.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2012-03-01/pdf/2012-4974.pdf"><span>77 FR 12495 - Revisions to the <span class="hlt">California</span> State Implementation Plan, Antelope <span class="hlt">Valley</span> Air Quality Management...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2012-03-01</p> <p>... the <span class="hlt">California</span> State Implementation Plan, Antelope <span class="hlt">Valley</span> Air Quality Management District and Mojave Desert Quality Management District AGENCY: Environmental Protection Agency (EPA). ACTION: Direct final... Quality Management District (AVAQMD) and Mojave Desert Air Quality Management District (MDAQMD) portion of...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/6697844-consortium-three-brings-real-geothermal-power-california-imperial-valley-last','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/6697844-consortium-three-brings-real-geothermal-power-california-imperial-valley-last"><span>A consortium of three brings real geothermal power for <span class="hlt">California</span>'s Imperial <span class="hlt">valley</span> -- at last</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Wehlage, E.F.</p> <p>1983-04-01</p> <p>Imperial <span class="hlt">Valley</span>'s geothermal history gets a whole new chapter with dedication ceremony for southern <span class="hlt">California</span>'s unusual 10,000 kilowatt power station-SCE in joint corporate venture with Southern Pacific and Union Oil. America's newest and unique electric power generation facility, The Salton Sea Geothermal-Electric Project, was the the site of a formal dedication ceremony while the sleek and stainless jacketed piping and machinery were displayed against a flawlessly brilliant January sky - blue and flecked with a few whisps of high white clouds, while plumes of geothermal steam rose across the desert. The occasion was the January 19, 1983, ceremonial dedication ofmore » the unique U.S.A. power generation facility constructed by an energy consortium under private enterprise, to make and deliver electricity, using geothermal steam released (with special cleaning and treatment) from magma-heated fluids produced at depths of 3,000 to 6,000 feet beneath the floor of the Imperial <span class="hlt">Valley</span> near Niland and Brawley, <span class="hlt">California</span>.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.5335S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.5335S"><span>Integrated <span class="hlt">Earthquake</span> Risk Assessment in the Kathmandu <span class="hlt">Valley</span> - A Case Study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schaper, Julia; Anhorn, Johannes; Khazai, Bijan; Nüsser, Marcus</p> <p>2013-04-01</p> <p>Rapid urban growth is a process which can be observed in cities worldwide. Managing these growing urban areas has become a major challenge for both governing bodies and citizens. Situated not only in a highly <span class="hlt">earthquake</span> and landslide-prone area, but comprising also the cultural and political capital of Nepal, the fast expanding Kathmandu <span class="hlt">Valley</span> in the Himalayan region is of particular interest. Vulnerability assessment has been an important tool for spatial planning in this already densely populated area. The magnitude 8.4 <span class="hlt">earthquake</span> of Bihar in 1934 cost 8600 Nepalis their lives, destroyed 20% of the Kathmandu building stock and heavily damaged another 40%. Since then, Kathmandu has grown into a hub with over a million inhabitants. Rapid infrastructure and population growth aggravate the vulnerability conditions, particularly in the core area of Metropolitan Kathmandu. We propose an integrative framework for vulnerability and risk in Kathmandu <span class="hlt">Valley</span>. In order to move towards a more systemic and integrated approach, we focus on interactions between natural hazards, physically engineered systems and society. High resolution satellite images are used to identify structural vulnerability of the building stock within the study area. Using object-based image analysis, the spatial dynamics of urban growth are assessed and validated using field data. Complementing this is the analysis of socio-economic attributes gained from databases and field surveys. An indicator-based vulnerability and resilience index will be operationalized using multi-attribute value theory and statistical methods such as principal component analysis. The results allow for a socio-economic comparison of places and their relative potential for harm and loss. The objective in this task is to better understand the interactions between nature and society, engineered systems and built environments through the development of an interdisciplinary framework on systemic seismic risk and vulnerability. Data</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.epa.gov/publicnotices/proposed-approval-california-air-plan-revision-san-joaquin-valley-unified-air','PESTICIDES'); return false;" href="https://www.epa.gov/publicnotices/proposed-approval-california-air-plan-revision-san-joaquin-valley-unified-air"><span>Proposed Approval of <span class="hlt">California</span> Air Plan Revision; San Joaquin <span class="hlt">Valley</span> Unified Air Pollution Control District; Reasonably Available Control Technology Demonstration</span></a></p> <p><a target="_blank" href="http://www.epa.gov/pesticides/search.htm">EPA Pesticide Factsheets</a></p> <p></p> <p></p> <p>EPA isproposing to approve revisions to the SJVUAPCD portion of the <span class="hlt">California</span> SIP applying to the San Joaquin <span class="hlt">Valley</span> of <span class="hlt">California</span> concerning demonstration regarding RACT requirements for the 2008 8-hour ozone National Ambient Air Quality Standard (NAAQS)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT.......308S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT.......308S"><span>Provenance, Offset Equivalent and Palinspastic Reconstruction of the Miocene Cajon <span class="hlt">Valley</span> Formation, Southern <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stang, Dallon Michael</p> <p></p> <p>Petrographic, conglomerate and detrital-zircon analyses of formations in southern <span class="hlt">California</span> can determine consanguineous petrofacies and lithofacies that help constrain paleotectonic and paleogeographic reconstructions of the southwestern United States. Arkosic sandstone of the lower Middle Miocene Cajon <span class="hlt">Valley</span> formation is exposed on the southwest edge of the Mojave block and juxtaposed against Mesozoic and Paleozoic rocks by the San Andreas fault (SAf). Early work in Cajon <span class="hlt">Valley</span> referred to the formation as Punchbowl, due to its similar appearance to the Punchbowl Formation at Devil's Punchbowl (northwest along the SAf). However, paleontological work placed Cajon <span class="hlt">Valley</span> strata in the Hemingfordian-Barstovian (18-14 Ma), as opposed to the Clarendonian-Hemphillian (13-9 Ma) Punchbowl Formation. Since the Cajon <span class="hlt">Valley</span> formation was deposited prior to being truncated by the San Andreas fault, the 2400m-thick, laterally extensive subaerial deposits likely were deposited across what is now the fault trace. Restoring 310 km of dextral slip on the SAf system should indicate the location of offset equivalent sandstone. Restoration of slip on the SAf system places Cajon <span class="hlt">Valley</span> adjacent to the Caliente and La Panza Ranges, east of San Luis Obispo. Although analysis of detrital zircon from Cenozoic sandstone throughout southern <span class="hlt">California</span> has been crucial in establishing paleodrainage areas, detrital zircon from the Cajon <span class="hlt">Valley</span> and equivalent formations had not been analyzed prior to this study. Paleocurrents measured throughout the Cajon <span class="hlt">Valley</span> formation indicate a source to the NE, in the Mojave Desert. Sandstone samples analyzed in thin section using the Gazzi-Dickinson method of point-counting are homogeneously arkosic, with slight compositional variability, making differentiation of the Cajon <span class="hlt">Valley</span> formation and potential offset equivalents problematic. However, Branch Canyon Sandstone and Santa Margarita Formation samples are compositionally the best match for the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730019521','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730019521"><span>ERTS Applications in <span class="hlt">earthquake</span> research and mineral exploration in <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Abdel-Gawad, M.; Silverstein, J.</p> <p>1973-01-01</p> <p>Examples that ERTS imagery can be effectively utilized to identify, locate, and map faults which show geomorphic evidence of geologically recent breakage are presented. Several important faults not previously known have been identified. By plotting epicenters of historic <span class="hlt">earthquakes</span> in parts of <span class="hlt">California</span>, Sonora, Mexico, Arizona, and Nevada, we found that areas known for historic seismicity are often characterized by abundant evidence of recent fault and crustal movements. There are many examples of seismically quiet areas where outstanding evidence of recent fault movements is observed. One application is clear: ERTS-1 imagery could be effectively utilized to delineate areas susceptible to <span class="hlt">earthquake</span> recurrence which, on the basis of seismic data alone, may be misleadingly considered safe. ERTS data can also be utilized in planning new sites in the geophysical network of fault movement monitoring and strain and tilt measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730004626','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730004626"><span><span class="hlt">Earthquake</span> epicenters and fault intersections in central and southern <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Abdel-Gawad, M. (Principal Investigator); Silverstein, J.</p> <p>1972-01-01</p> <p>The author has identifed the following significant results. ERTS-1 imagery provided evidence for the existence of short transverse fault segments lodged between faults of the San Andreas system in the Coast Ranges, <span class="hlt">California</span>. They indicate that an early episode of transverse shear has affected the Coast Ranges prior to the establishment of the present San Andreas fault. The fault has been offset by transverse faults of the Transverse Ranges. It appears feasible to identify from ERTS-1 imagery geomorphic criteria of recent fault movements. Plots of historic <span class="hlt">earthquakes</span> in the Coast Ranges and western Transverse Ranges show clusters in areas where structures are complicated by interaction of tow active fault systems. A fault lineament apparently not previously mapped was identified in the Uinta Mountains, Utah. Part of the lineament show evidence of recent faulting which corresponds to a moderate <span class="hlt">earthquake</span> cluster.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70026886','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70026886"><span>Losses to single-family housing from ground motions in the 1994 Northridge, <span class="hlt">California</span>, <span class="hlt">earthquake</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wesson, R.L.; Perkins, D.M.; Leyendecker, E.V.; Roth, R.J.; Petersen, M.D.</p> <p>2004-01-01</p> <p>The distributions of insured losses to single-family housing following the 1994 Northridge, <span class="hlt">California</span>, <span class="hlt">earthquake</span> for 234 ZIP codes can be satisfactorily modeled with gamma distributions. Regressions of the parameters in the gamma distribution on estimates of ground motion, derived from ShakeMap estimates or from interpolated observations, provide a basis for developing curves of conditional probability of loss given a ground motion. Comparison of the resulting estimates of aggregate loss with the actual aggregate loss gives satisfactory agreement for several different ground-motion parameters. Estimates of loss based on a deterministic spatial model of the <span class="hlt">earthquake</span> ground motion, using standard attenuation relationships and NEHRP soil factors, give satisfactory results for some ground-motion parameters if the input ground motions are increased about one and one-half standard deviations above the median, reflecting the fact that the ground motions for the Northridge <span class="hlt">earthquake</span> tended to be higher than the median ground motion for other <span class="hlt">earthquakes</span> with similar magnitude. The results give promise for making estimates of insured losses to a similar building stock under future <span class="hlt">earthquake</span> loading. ?? 2004, <span class="hlt">Earthquake</span> Engineering Research Institute.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://rosap.ntl.bts.gov/view/dot/28828','DOTNTL'); return false;" href="https://rosap.ntl.bts.gov/view/dot/28828"><span>Great East Japan <span class="hlt">earthquake</span>, JR East mitigation successes, and lessons for <span class="hlt">California</span> high-speed rail.</span></a></p> <p><a target="_blank" href="http://ntlsearch.bts.gov/tris/index.do">DOT National Transportation Integrated Search</a></p> <p></p> <p>2015-04-01</p> <p><span class="hlt">California</span> and Japan both experience frequent seismic activity, which is often damaging to infrastructure. Seismologists have : developed systems for detecting and analyzing <span class="hlt">earthquakes</span> in real-time. JR East has developed systems to mitigate the : da...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.A43B0130W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.A43B0130W"><span>Thirty Years of Cloud Cover Patterns from Satellite Data: Fog in <span class="hlt">California</span>'s Central <span class="hlt">Valley</span> and Coast</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Waller, E.; Baldocchi, D. D.</p> <p>2012-12-01</p> <p>In an effort to assess long term trends in winter fog in the Central <span class="hlt">Valley</span> of <span class="hlt">California</span>, custom maps of daily cloud cover from an approximately 30 year record of AVHRR (1981-1999) and MODIS (2000-2012) satellite data were generated. Spatial rules were then used to differentiate between fog and general cloud cover. Differences among the sensors (e.g., spectral content, spatial resolution, overpass time) presented problems of consistency, but concurrent climate station data were used to resolve systematic differences in products, and to confirm long term trends. The frequency and extent of Central <span class="hlt">Valley</span> ("Tule") fog appear to have some periodic oscillation, but also appear to be on the decline, especially in the Sacramento <span class="hlt">Valley</span> and in the "shoulder" months of November and February. These results may have strong implications for growers of fruit and nut trees in the Central <span class="hlt">Valley</span> dependent on winter chill hours that are augmented by the foggy daytime conditions. Conclusions about long term trends in fog are limited to daytime patterns, as results are primarily derived from reflectance-based products. Similar analyses of daytime cloud cover are performed on other areas of concern, such as the coastal fog belt of <span class="hlt">California</span>. Large area and long term patterns here appear to have periodic oscillation similar to that for the Central <span class="hlt">Valley</span>. However, the relatively coarse spatial resolution of the AVHRR LTDR (Long Term Data Record) data (~5-km) may be limiting for fine-scale analysis of trends.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=inclusion&pg=3&id=EJ1139067','ERIC'); return false;" href="https://eric.ed.gov/?q=inclusion&pg=3&id=EJ1139067"><span>Constrained Inclusion: Access and Persistence Among Undocumented Community College Students in <span class="hlt">California</span>'s Central <span class="hlt">Valley</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Negrón-Gonzales, Genevieve</p> <p>2017-01-01</p> <p>This article examines the ways in which citizenship status uniquely shapes both the access and persistence of undocumented community college students in the Central <span class="hlt">Valley</span> of <span class="hlt">California</span>. Drawing on more than 2 years of qualitative fieldwork, it is argued that undocumented community college students navigate an institutional landscape of…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.S51C2429N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.S51C2429N"><span>Web Services and Other Enhancements at the Northern <span class="hlt">California</span> <span class="hlt">Earthquake</span> Data Center</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Neuhauser, D. S.; Zuzlewski, S.; Allen, R. M.</p> <p>2012-12-01</p> <p>The Northern <span class="hlt">California</span> <span class="hlt">Earthquake</span> Data Center (NCEDC) provides data archive and distribution services for seismological and geophysical data sets that encompass northern <span class="hlt">California</span>. The NCEDC is enhancing its ability to deliver rapid information through Web Services. NCEDC Web Services use well-established web server and client protocols and REST software architecture to allow users to easily make queries using web browsers or simple program interfaces and to receive the requested data in real-time rather than through batch or email-based requests. Data are returned to the user in the appropriate format such as XML, RESP, or MiniSEED depending on the service, and are compatible with the equivalent IRIS DMC web services. The NCEDC is currently providing the following Web Services: (1) Station inventory and channel response information delivered in StationXML format, (2) Channel response information delivered in RESP format, (3) Time series availability delivered in text and XML formats, (4) Single channel and bulk data request delivered in MiniSEED format. The NCEDC is also developing a rich <span class="hlt">Earthquake</span> Catalog Web Service to allow users to query <span class="hlt">earthquake</span> catalogs based on selection parameters such as time, location or geographic region, magnitude, depth, azimuthal gap, and rms. It will return (in QuakeML format) user-specified results that can include simple <span class="hlt">earthquake</span> parameters, as well as observations such as phase arrivals, codas, amplitudes, and computed parameters such as first motion mechanisms, moment tensors, and rupture length. The NCEDC will work with both IRIS and the International Federation of Digital Seismograph Networks (FDSN) to define a uniform set of web service specifications that can be implemented by multiple data centers to provide users with a common data interface across data centers. The NCEDC now hosts <span class="hlt">earthquake</span> catalogs and waveforms from the US Department of Energy (DOE) Enhanced Geothermal Systems (EGS) monitoring networks. These</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70168841','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70168841"><span><span class="hlt">Earthquakes</span>, September-October 1984</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Person, W.J.</p> <p>1985-01-01</p> <p>In the United States, Wyoming experienced a couple of moderate <span class="hlt">earthquakes</span>, and off the coast of northern <span class="hlt">California</span>, a strong <span class="hlt">earthquake</span> shook much of the northern coast of <span class="hlt">California</span> and parts of the Oregon coast. </p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.T21B2806F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.T21B2806F"><span>Structure of the San Andreas Fault Zone in the Salton Trough Region of Southern <span class="hlt">California</span>: A Comparison with San Andreas Fault Structure in the Loma Prieta Area of Central <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fuis, G. S.; Catchings, R.; Scheirer, D. S.; Goldman, M.; Zhang, E.; Bauer, K.</p> <p>2016-12-01</p> <p>The San Andreas fault (SAF) in the northern Salton Trough, or Coachella <span class="hlt">Valley</span>, in southern <span class="hlt">California</span>, appears non-vertical and non-planar. In cross section, it consists of a steeply dipping segment (75 deg dip NE) from the surface to 6- to 9-km depth, and a moderately dipping segment below 6- to 9-km depth (50-55 deg dip NE). It also appears to branch upward into a flower-like structure beginning below about 10-km depth. Images of the SAF zone in the Coachella <span class="hlt">Valley</span> have been obtained from analysis of steep reflections, <span class="hlt">earthquakes</span>, modeling of potential-field data, and P-wave tomography. Review of seismological and geodetic research on the 1989 M 6.9 Loma Prieta <span class="hlt">earthquake</span>, in central <span class="hlt">California</span> (e.g., U.S. Geological Survey Professional Paper 1550), shows several features of SAF zone structure similar to those seen in the northern Salton Trough. Aftershocks in the Loma Prieta epicentral area form two chief clusters, a tabular zone extending from 18- to 9-km depth and a complex cluster above 5-km depth. The deeper cluster has been interpreted to surround the chief rupture plane, which dips 65-70 deg SW. When double-difference <span class="hlt">earthquake</span> locations are plotted, the shallower cluster contains tabular subclusters that appear to connect the main rupture with the surface traces of the Sargent and Berrocal faults. In addition, a diffuse cluster may surround a steep to vertical fault connecting the main rupture to the surface trace of the SAF. These interpreted fault connections from the main rupture to surface fault traces appear to define a flower-like structure, not unlike that seen above the moderately dipping segment of the SAF in the Coachella <span class="hlt">Valley</span>. But importantly, the SAF, interpreted here to include the main rupture plane, appears segmented, as in the Coachella <span class="hlt">Valley</span>, with a moderately dipping segment below 9-km depth and a steep to vertical segment above that depth. We hope to clarify fault-zone structure in the Loma Prieta area by reanalyzing active</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70160541','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70160541"><span>Water availability and land subsidence in the Central <span class="hlt">Valley</span>, <span class="hlt">California</span>, USA</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Faunt, Claudia; Sneed, Michelle; Traum, Jonathan A.; Brandt, Justin</p> <p>2016-01-01</p> <p>The Central <span class="hlt">Valley</span> in <span class="hlt">California</span> (USA) covers about 52,000 km2 and is one of the most productive agricultural regions in the world. This agriculture relies heavily on surface-water diversions and groundwater pumpage to meet irrigation water demand. Because the <span class="hlt">valley</span> is semi-arid and surface-water availability varies substantially, agriculture relies heavily on local groundwater. In the southern two thirds of the <span class="hlt">valley</span>, the San Joaquin <span class="hlt">Valley</span>, historic and recent groundwater pumpage has caused significant and extensive drawdowns, aquifer-system compaction and subsidence. During recent drought periods (2007–2009 and 2012-present), groundwater pumping has increased owing to a combination of decreased surface-water availability and land-use changes. Declining groundwater levels, approaching or surpassing historical low levels, have caused accelerated and renewed compaction and subsidence that likely is mostly permanent. The subsidence has caused operational, maintenance, and construction-design problems for water-delivery and flood-control canals in the San Joaquin <span class="hlt">Valley</span>. Planning for the effects of continued subsidence in the area is important for water agencies. As land use, managed aquifer recharge, and surface-water availability continue to vary, long-term groundwater-level and subsidence monitoring and modelling are critical to understanding the dynamics of historical and continued groundwater use resulting in additional water-level and groundwater storage declines, and associated subsidence. Modeling tools such as the Central <span class="hlt">Valley</span> Hydrologic Model, can be used in the evaluation of management strategies to mitigate adverse impacts due to subsidence while also optimizing water availability. This knowledge will be critical for successful implementation of recent legislation aimed toward sustainable groundwater use.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.S41A2415B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.S41A2415B"><span>What to Expect from the Virtual Seismologist: Delay Times and Uncertainties of Initial <span class="hlt">Earthquake</span> Alerts in <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Behr, Y.; Cua, G. B.; Clinton, J. F.; Racine, R.; Meier, M.; Cauzzi, C.</p> <p>2013-12-01</p> <p>The Virtual Seismologist (VS) method is a Bayesian approach to regional network-based <span class="hlt">earthquake</span> early warning (EEW) originally formulated by Cua and Heaton (2007). Implementation of VS into real-time EEW codes has been an on-going effort of the Swiss Seismological Service at ETH Zürich since 2006, with support from ETH Zürich, various European projects, and the United States Geological Survey (USGS). VS is one of three EEW algorithms that form the basis of the <span class="hlt">California</span> Integrated Seismic Network (CISN) ShakeAlert system, a USGS-funded prototype end-to-end EEW system that could potentially be implemented in <span class="hlt">California</span>. In Europe, VS is currently operating as a real-time test system in Switzerland, western Greece and Istanbul. As part of the on-going EU project REAKT (Strategies and Tools for Real-Time <span class="hlt">Earthquake</span> Risk Reduction), VS installations in southern Italy, Romania, and Iceland are planned or underway. The possible use cases for an EEW system will be determined by the speed and reliability of <span class="hlt">earthquake</span> source parameter estimates. A thorough understanding of both is therefore essential to evaluate the usefulness of VS. For <span class="hlt">California</span>, we present state-wide theoretical alert times for hypothetical <span class="hlt">earthquakes</span> by analyzing time delays introduced by the different components in the VS EEW system. Taking advantage of the fully probabilistic formulation of the VS algorithm we further present an improved way to describe the uncertainties of every magnitude estimate by evaluating the width and shape of the probability density function that describes the relationship between waveform envelope amplitudes and magnitude. We evaluate these new uncertainty values for past seismicity in <span class="hlt">California</span> through off-line playbacks and compare them to the previously defined static definitions of uncertainty based on real-time detections. Our results indicate where VS alerts are most useful in <span class="hlt">California</span> and also suggest where most effective improvements to the VS EEW system</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70014060','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70014060"><span>Monitoring unrest in a large silicic caldera, the long <span class="hlt">Valley</span>-inyo craters volcanic complex in east-central <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hill, D.P.</p> <p>1984-01-01</p> <p>Recent patterns of geologic unrest in long <span class="hlt">Valley</span> caldera in east-central <span class="hlt">California</span> emphasize that this large, silicic volcanic system and the adjacent, geologically youthful Inyo-Mono Craters volcanic chain are still active and capable of producing locally hazardous volcanic eruptions. A series of four magnitude -6 <span class="hlt">earthquakes</span> in May 1980 called attention to this current episode of unrest, and subsequent activity has included numerous <span class="hlt">earthquake</span> swarms in the south moat of the caldera accompanied by inflation of the resurgent dome by more than 50 cm over the last five years. The seismicity associated with this unrest is currently monitored by a network of 31 telemetered seismic stations with an automatic processing system that yelds hypocentral locations and <span class="hlt">earthquake</span> magnitudes in near-real time. Deformation of the ground is monitored by a) a series of overlapping trilateration networks that provide coverage ranging from annual measurements of regional deformation to daily measurements of deformation local to the active, southern section of the caldera, b) a regional network of level lines surveyed annually, c) a regional network of precise gravity stations occupied annually, d) local, L-shaped level figures surveyed every few months, and e) a network of fourteen borehole tiltmeter clusters (two instruments in each cluster) and a borehole dilatometer, the telemetered signals from which provide continuous data on deformation rates. Additional telemetered data provide continuous information on fluctuations in the local magnetic field, hydrogen gas emission rates at three sites, and water level and temperatures in three wells. Continuous data on disharge rates and temperatures from hot springs and fumaroles are collected by several on-site recorders within the caldera, and samples for liquid and gas chemistry are collected several times per year from selected hot springs and fumaroles. ?? 1984 Intern. Association of Volcanology and Chemistry of the Earth</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1984BVol...47..371H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1984BVol...47..371H"><span>Monitoring unrest in a large silicic caldera, the long <span class="hlt">Valley</span>-inyo craters volcanic complex in east-central <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hill, D. P.</p> <p>1984-06-01</p> <p>Recent patterns of geologic unrest in long <span class="hlt">Valley</span> caldera in east-central <span class="hlt">California</span> emphasize that this large, silicic volcanic system and the adjacent, geologically youthful Inyo-Mono Craters volcanic chain are still active and capable of producing locally hazardous volcanic eruptions. A series of four magnitude -6 <span class="hlt">earthquakes</span> in May 1980 called attention to this current episode of unrest, and subsequent activity has included numerous <span class="hlt">earthquake</span> swarms in the south moat of the caldera accompanied by inflation of the resurgent dome by more than 50 cm over the last five years. The seismicity associated with this unrest is currently monitored by a network of 31 telemetered seismic stations with an automatic processing system that yelds hypocentral locations and <span class="hlt">earthquake</span> magnitudes in near-real time. Deformation of the ground is monitored by a) a series of overlapping trilateration networks that provide coverage ranging from annual measurements of regional deformation to daily measurements of deformation local to the active, southern section of the caldera, b) a regional network of level lines surveyed annually, c) a regional network of precise gravity stations occupied annually, d) local, L-shaped level figures surveyed every few months, and e) a network of fourteen borehole tiltmeter clusters (two instruments in each cluster) and a borehole dilatometer, the telemetered signals from which provide continuous data on deformation rates. Additional telemetered data provide continuous information on fluctuations in the local magnetic field, hydrogen gas emission rates at three sites, and water level and temperatures in three wells. Continuous data on disharge rates and temperatures from hot springs and fumaroles are collected by several on-site recorders within the caldera, and samples for liquid and gas chemistry are collected several times per year from selected hot springs and fumaroles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.S33F4902E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.S33F4902E"><span>Co- and post-seismic deformation for the 2014 Napa <span class="hlt">Valley</span> <span class="hlt">Earthquake</span> from Sentinel-1A interferometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Elliott, J. R.; Wright, T. J.; Elliott, A. J.; González, P. J.; Hooper, A. J.; Larsen, Y.; Marinkovic, P.; Plain, M.; Walters, R. J.</p> <p>2014-12-01</p> <p>Here we present analysis of co- and post-seismic deformation for the 24 August 2014 Napa <span class="hlt">Valley</span> <span class="hlt">Earthquake</span> derived from Sentinel-1A interferometry. We use these to derive the co-seismic slip distribution and map the evolution of post-seismic afterslip. The 24 August 2014 Napa <span class="hlt">Valley</span> <span class="hlt">earthquake</span> was the first <span class="hlt">earthquake</span> for which surface deformation was measured by Sentinel-1A, a new radar satellite launched by the European Space Agency on 3 April 2014, and operated by the European Commission's Copernicus program. Sentinel-1A reached its final operational orbit on 7 August, and fortuitously acquired a pre-<span class="hlt">earthquake</span> image of the San Francisco Bay area on that day in StripMap mode. By comparing it with an image acquired on 31 August, we formed a co-seismic interferogram, which reveals the surface deformation that occurred during the <span class="hlt">earthquake</span> and the first 7 days of the post-seismic period. We use this to constrain a simple elastic model of the co-seismic slip distribution; preliminary inversion results show that the slip at depth reached a peak of >1.5 m at a depth of ~4 km. Following the <span class="hlt">earthquake</span>, Sentinel-1A has acquired further acquisitions in both StripMap and Interferometric Wide Swath modes. The first 12-day post-seismic StripMap interferogram shows a sharp discontinuity along the entire fault rupture, consistent with field observations of rapid afterslip. We will use the full time series from August to December to measure the spatio-temporal behaviour of the afterslip, and discuss the implications for the frictional properties of the fault. The results from Napa point to an exciting and impactful future for the Sentinel-1 radar constellation. By mid-2014, Sentinel-1A will be acquiring data systematically over all the seismic belts, and the launch of Sentinel-1B in 2016 will increase the temporal frequency of acquisitions. The data will be available free of charge and will transform our ability to conduct tectonic geodesy, particularly in remote areas of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.T53B2124G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.T53B2124G"><span>GPS coseismic and postseismic surface displacements of the El Mayor-Cucapah <span class="hlt">earthquake</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gonzalez, A.; Gonzalez-Garcia, J. J.; Sandwell, D. T.; Fialko, Y.; Agnew, D. C.; Lipovsky, B.; Fletcher, J. M.; Nava Pichardo, F. A.</p> <p>2010-12-01</p> <p>GPS surveys were performed after the El Mayor Cucapah <span class="hlt">earthquake</span> Mw 7.2 in northern Baja <span class="hlt">California</span> by scientists from CICESE, UCSD, and UCR. Six of the sites were occupied for several weeks to capture the postseismic deformation within a day of the <span class="hlt">earthquake</span>. We calculated the coseismic displacement for 22 sites with previous secular velocity in ITRF2005 reference frame and found 1.160±0.016 m of maximum horizontal displacement near the epicentral area at La Puerta location, and 0.636±0.036 m of vertical offset near Ejido Durango. Most of the GPS sites are located East of the main rupture in Mexicali <span class="hlt">Valley</span>, 5 are located West at Sierra Juarez and South near San Felipe. We present a velocity field before, along with coseismic displacements and early postseismic features related to the El Mayor-Cucapah <span class="hlt">earthquake</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70026246','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70026246"><span>Remotely triggered seismicity on the United States west coast following the Mw 7.9 Denali fault <span class="hlt">earthquake</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Prejean, S.G.; Hill, D.P.; Brodsky, E.E.; Hough, S.E.; Johnston, M.J.S.; Malone, S.D.; Oppenheimer, D.H.; Pitt, A.M.; Richards-Dinger, K. B.</p> <p>2004-01-01</p> <p>The Mw 7.9 Denali fault <span class="hlt">earthquake</span> in central Alaska of 3 November 2002 triggered <span class="hlt">earthquakes</span> across western North America at epicentral distances of up to at least 3660 km. We describe the spatial and temporal development of triggered activity in <span class="hlt">California</span> and the Pacific Northwest, focusing on Mount Rainier, the Geysers geothermal field, the Long <span class="hlt">Valley</span> caldera, and the Coso geothermal field.The onset of triggered seismicity at each of these areas began during the Love and Raleigh waves of the Mw 7.9 wave train, which had dominant periods of 15 to 40 sec, indicating that <span class="hlt">earthquakes</span> were triggered locally by dynamic stress changes due to low-frequency surface wave arrivals. Swarms during the wave train continued for ∼4 min (Mount Rainier) to ∼40 min (the Geysers) after the surface wave arrivals and were characterized by spasmodic bursts of small (M ≤ 2.5) <span class="hlt">earthquakes</span>. Dynamic stresses within the surface wave train at the time of the first triggered <span class="hlt">earthquakes</span> ranged from 0.01 MPa (Coso) to 0.09 MPa (Mount Rainier). In addition to the swarms that began during the surface wave arrivals, Long <span class="hlt">Valley</span> caldera and Mount Rainier experienced unusually large seismic swarms hours to days after the Denali fault <span class="hlt">earthquake</span>. These swarms seem to represent a delayed response to the Denali fault <span class="hlt">earthquake</span>. The occurrence of spatially and temporally distinct swarms of triggered seismicity at the same site suggests that <span class="hlt">earthquakes</span> may be triggered by more than one physical process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/pp/1551c/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/pp/1551c/report.pdf"><span>Chapter C. The Loma Prieta, <span class="hlt">California</span>, <span class="hlt">Earthquake</span> of October 17, 1989 - Landslides</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Keefer, David K.</p> <p>1998-01-01</p> <p>Central <span class="hlt">California</span>, in the vicinity of San Francisco and Monterey Bays, has a history of fatal and damaging landslides, triggered by heavy rainfall, coastal and stream erosion, construction activity, and <span class="hlt">earthquakes</span>. The great 1906 San Francisco <span class="hlt">earthquake</span> (MS=8.2-8.3) generated more than 10,000 landslides throughout an area of 32,000 km2; these landslides killed at least 11 people and caused substantial damage to buildings, roads, railroads, and other civil works. Smaller numbers of landslides, which caused more localized damage, have also been reported from at least 20 other <span class="hlt">earthquakes</span> that have occurred in the San Francisco Bay-Monterey Bay region since 1838. Conditions that make this region particularly susceptible to landslides include steep and rugged topography, weak rock and soil materials, seasonally heavy rainfall, and active seismicity. Given these conditions and history, it was no surprise that the 1989 Loma Prieta <span class="hlt">earthquake</span> generated thousands of landslides throughout the region. Landslides caused one fatality and damaged at least 200 residences, numerous roads, and many other structures. Direct damage from landslides probably exceeded $30 million; additional, indirect economic losses were caused by long-term landslide blockage of two major highways and by delays in rebuilding brought about by concern over the potential long-term instability of some <span class="hlt">earthquake</span>-damaged slopes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=233214','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=233214"><span>Biology and Molecular Characterization of Cucurbit leaf crumple virus, an Emergent Cucurbit-Infecting Begomovirus in the Imperial <span class="hlt">Valley</span> of <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Cucurbit leaf crumple virus (CuLCrV) is an emergent and potentially economically important bipartite begomovirus first identified in volunteer watermelon plants in the Imperial <span class="hlt">Valley</span> of southern <span class="hlt">California</span> in 1998. Field surveys indicated that CuLCrV has become established in the Imperial <span class="hlt">Valley</span>; a...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/1985/0401/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/1985/0401/report.pdf"><span>Water budgets for major streams in the Central <span class="hlt">Valley</span>, <span class="hlt">California</span>, 1961-77</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Mullen, J.R.; Nady, Paul</p> <p>1985-01-01</p> <p>A compilation of annual streamflow data for 20 major stream systems in the central <span class="hlt">Valley</span> of <span class="hlt">California</span>, for water years 1961-77, is presented. The water-budget tables list gaged and ungaged inflow from tributaries and canals, diversions, and gaged outflow. Theoretical outflow and gain or loss in a reach are computed. A schematic diagram and explanation of the data are provided for each water-budget table. (USGS)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70025561','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70025561"><span>Deformation of the Long <span class="hlt">Valley</span> Caldera, <span class="hlt">California</span>: Inferences from measurements from 1988 to 2001</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Langbein, J.O.</p> <p>2003-01-01</p> <p>Two periods of volcanic unrest occurred between 1989 and 1998 in the Long <span class="hlt">Valley</span> Caldera, eastern <span class="hlt">California</span>. Numerous <span class="hlt">earthquakes</span> were recorded, and these periods of unrest were documented with high-precision geodetic measurements. The first round of unrest started rapidly in late 1989 and slowly decreased in rate through the early 1990s. For this interval there are both leveling and two-color electronic distance meter (EDM) measurements. The second round of unrest started slowly in mid-1997, climaxed in late 1997, and rapidly returned to quiescence by mid-1998. Deformation was recorded by both the two-color EDM and continuous GPS. Both episodes require inflation at 6-7 km beneath the resurgent dome, and both episodes had roughly 0.1 m extension across the resurgent dome. In addition, the data presented here suggest that there is a deeper, 10-20 km, inflation source beneath the south moat of the caldera. For both episodes, the better-resolved inflation beneath the resurgent dome is a near-vertical, prolate spheroid rather than an isotropic source, which suggests that magma came up through vertical cracks. However, the modeling suggests that the location changed with the depth from 6.0 to 6.7 km for the later episode. In contrast to the earlier episode, the 1997-1998 episode has additional deformation in the south moat, where the simplest model is that of a right-lateral slip on a steeply dipping plane that is defined by the location of <span class="hlt">earthquakes</span> in the south moat. Models of the time-dependent behavior suggest that slip on this fault occurred from late November through December 1997, corresponding to the time of greatest moment release by the <span class="hlt">earthquake</span> swarm in the south moat. Confounding the interpretation of these data is an active geothermal field near the center of the EDM network and adjacent to the south moat and resurgent dome. Additional modeling of leveling and EDM data within the geothermal field during a period of low rate of inflation of the dome</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeoJI.200..322Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeoJI.200..322Y"><span>Maximum magnitude estimations of induced <span class="hlt">earthquakes</span> at Paradox <span class="hlt">Valley</span>, Colorado, from cumulative injection volume and geometry of seismicity clusters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yeck, William L.; Block, Lisa V.; Wood, Christopher K.; King, Vanessa M.</p> <p>2015-01-01</p> <p>The Paradox <span class="hlt">Valley</span> Unit (PVU), a salinity control project in southwest Colorado, disposes of brine in a single deep injection well. Since the initiation of injection at the PVU in 1991, <span class="hlt">earthquakes</span> have been repeatedly induced. PVU closely monitors all seismicity in the Paradox <span class="hlt">Valley</span> region with a dense surface seismic network. A key factor for understanding the seismic hazard from PVU injection is the maximum magnitude <span class="hlt">earthquake</span> that can be induced. The estimate of maximum magnitude of induced <span class="hlt">earthquakes</span> is difficult to constrain as, unlike naturally occurring <span class="hlt">earthquakes</span>, the maximum magnitude of induced <span class="hlt">earthquakes</span> changes over time and is affected by injection parameters. We investigate temporal variations in maximum magnitudes of induced <span class="hlt">earthquakes</span> at the PVU using two methods. First, we consider the relationship between the total cumulative injected volume and the history of observed largest <span class="hlt">earthquakes</span> at the PVU. Second, we explore the relationship between maximum magnitude and the geometry of individual seismicity clusters. Under the assumptions that: (i) elevated pore pressures must be distributed over an entire fault surface to initiate rupture and (ii) the location of induced events delineates volumes of sufficiently high pore-pressure to induce rupture, we calculate the largest allowable vertical penny-shaped faults, and investigate the potential <span class="hlt">earthquake</span> magnitudes represented by their rupture. Results from both the injection volume and geometrical methods suggest that the PVU has the potential to induce events up to roughly MW 5 in the region directly surrounding the well; however, the largest observed <span class="hlt">earthquake</span> to date has been about a magnitude unit smaller than this predicted maximum. In the seismicity cluster surrounding the injection well, the maximum potential <span class="hlt">earthquake</span> size estimated by these methods and the observed maximum magnitudes have remained steady since the mid-2000s. These observations suggest that either these methods</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/mf/2002/mf-2381/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/mf/2002/mf-2381/"><span>Isostatic gravity map of the Death <span class="hlt">Valley</span> ground-water model area, Nevada and <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ponce, D.A.; Blakely, R.J.; Morin, R.L.; Mankinen, E.A.</p> <p>2001-01-01</p> <p>An isostatic gravity map of the Death <span class="hlt">Valley</span> groundwater model area was prepared from over 40,0000 gravity stations as part of an interagency effort by the U.S. Geological Survey and the U.S. Department of Energy to help characterize the geology and hydrology of southwest Nevada and parts of <span class="hlt">California</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17738534','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17738534"><span><span class="hlt">Earthquake</span> Swarm Along the San Andreas Fault near Palmdale, Southern <span class="hlt">California</span>, 1976 to 1977.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McNally, K C; Kanamori, H; Pechmann, J C; Fuis, G</p> <p>1978-09-01</p> <p>Between November 1976 and November 1977 a swarm of small <span class="hlt">earthquakes</span> (local magnitude </= 3) occurred on or near the San Andreas fault near Palmdale, <span class="hlt">California</span>. This swarm was the first observed along this section of the San Andreas since cataloging of instrumental data began in 1932. The activity followed partial subsidence of the 35-centimeter vertical crustal uplift known as the Palmdale bulge along this "locked" section of the San Andreas, which last broke in the great (surface-wave magnitude = 8(1/4)+) 1857 Fort Tejon <span class="hlt">earthquake</span>. The swarm events exhibit characteristics previously observed for some foreshock sequences, such as tight clustering of hypocenters and time-dependent rotations of stress axes inferred from focal mechanisms. However, because of our present lack of understanding of the processes that precede <span class="hlt">earthquake</span> faulting, the implications of the swarm for future large <span class="hlt">earthquakes</span> on the San Andreas fault are unknown.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70012399','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70012399"><span><span class="hlt">Earthquake</span> swarm along the San Andreas fault near Palmdale, Southern <span class="hlt">California</span>, 1976 to 1977</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Mcnally, K.C.; Kanamori, H.; Pechmann, J.C.; Fuis, G.</p> <p>1978-01-01</p> <p>Between November 1976 and November 1977 a swarm of small <span class="hlt">earthquakes</span> (local magnitude ??? 3) occurred on or near the San Andreas fault near Palmdale, <span class="hlt">California</span>. This swarm was the first observed along this section of the San Andreas since cataloging of instrumental data began in 1932. The activity followed partial subsidence of the 35-centimeter vertical crustal uplift known as the Palmdale bulge along this "locked" section of the San Andreas, which last broke in the great (surface-wave magnitude = 81/4+) 1857 Fort Tejon <span class="hlt">earthquake</span>. The swarm events exhibit characteristics previously observed for some foreshock sequences, such as tight clustering of hypocenters and time-dependent rotations of stress axes inferred from focal mechanisms. However, because of our present lack of understanding of the processes that precede <span class="hlt">earthquake</span> faulting, the implications of the swarm for future large <span class="hlt">earthquakes</span> on the San Andreas fault are unknown. Copyright ?? 1978 AAAS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70188363','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70188363"><span>ViscoSim <span class="hlt">Earthquake</span> Simulator</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Pollitz, Fred</p> <p>2012-01-01</p> <p>Synthetic seismicity simulations have been explored by the Southern <span class="hlt">California</span> <span class="hlt">Earthquake</span> Center (SCEC) <span class="hlt">Earthquake</span> Simulators Group in order to guide long‐term forecasting efforts related to the Unified <span class="hlt">California</span> <span class="hlt">Earthquake</span> Rupture Forecast (Tullis et al., 2012a). In this study I describe the viscoelastic <span class="hlt">earthquake</span> simulator (ViscoSim) of Pollitz, 2009. Recapitulating to a large extent material previously presented by Pollitz (2009, 2011) I describe its implementation of synthetic ruptures and how it differs from other simulators being used by the group.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2010/1010/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2010/1010/"><span>The Quaternary Silver Creek Fault Beneath the Santa Clara <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wentworth, Carl M.; Williams, Robert A.; Jachens, Robert C.; Graymer, Russell W.; Stephenson, William J.</p> <p>2010-01-01</p> <p>The northwest-trending Silver Creek Fault is a 40-km-long strike-slip fault in the eastern Santa Clara <span class="hlt">Valley</span>, <span class="hlt">California</span>, that has exhibited different behaviors within a changing San Andreas Fault system over the past 10-15 Ma. Quaternary alluvium several hundred meters thick that buries the northern half of the Silver Creek Fault, and that has been sampled by drilling and imaged in a detailed seismic reflection profile, provides a record of the Quaternary history of the fault. We assemble evidence from areal geology, stratigraphy, paleomagnetics, ground-water hydrology, potential-field geophysics, and reflection and <span class="hlt">earthquake</span> seismology to determine the long history of the fault in order to evaluate its current behavior. The fault formed in the Miocene more than 100 km to the southeast, as the southwestern fault in a 5-km-wide right step to the Hayward Fault, within which the 40-km-long Evergreen pull-apart basin formed. Later, this basin was obliquely cut by the newly recognized Mt. Misery Fault to form a more direct connection to the Hayward Fault, although continued growth of the basin was sufficient to accommodate at least some late Pliocene alluvium. Large offset along the San Andreas-Calaveras-Mt Misery-Hayward Faults carried the basin northwestward almost to its present position when, about 2 Ma, the fault system was reorganized. This led to near abandonment of the faults bounding the pull-apart basin in favor of right slip extending the Calaveras Fault farther north before stepping west to the Hayward Fault, as it does today. Despite these changes, the Silver Creek Fault experienced a further 200 m of dip slip in the early Quaternary, from which we infer an associated 1.6 km or so of right slip, based on the ratio of the 40-km length of the strike-slip fault to a 5-km depth of the Evergreen Basin. This dip slip ends at a mid-Quaternary unconformity, above which the upper 300 m of alluvial cover exhibits a structural sag at the fault that we interpret as</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70023270','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70023270"><span>Site response, shallow shear-wave velocity, and damage in Los Gatos, <span class="hlt">California</span>, from the 1989 Loma Prieta <span class="hlt">earthquake</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hartzell, S.; Carver, D.; Williams, R.A.</p> <p>2001-01-01</p> <p>Aftershock records of the 1989 Loma Prieta <span class="hlt">earthquake</span> are used to calculate site response in the frequency band of 0.5-10 Hz at 24 locations in Los Gatos, <span class="hlt">California</span>, on the edge of the Santa Clara <span class="hlt">Valley</span>. Two different methods are used: spectral ratios relative to a reference site on rock and a source/site spectral inversion method. These two methods complement each other and give consistent results. Site amplification factors are compared with surficial geology, thickness of alluvium, shallow shear-wave velocity measurements, and ground deformation and structural damage resulting from the Loma Prieta <span class="hlt">earthquake</span>. Higher values of site amplification are seen on Quaternary alluvium compared with older Miocene and Cretaceous units of Monterey and Franciscan Formation. However, other more detailed correlations with surficial geology are not evident. A complex pattern of alluvial sediment thickness, caused by crosscutting thrust faults, is interpreted as contributing to the variability in site response and the presence of spectral resonance peaks between 2 and 7 Hz at some sites. Within the range of our field measurements, there is a correlation between lower average shear-wave velocity of the top 30 m and 50% higher values of site amplification. An area of residential homes thrown from their foundations correlates with high site response. This damage may also have been aggravated by local ground deformation. Severe damage to commercial buildings in the business district, however, is attributed to poor masonry construction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/9641','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/9641"><span>Land subsidence in the San Joaquin <span class="hlt">Valley</span>, <span class="hlt">California</span>, as of 1980</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ireland, R.L.; Poland, J.F.; Riley, F.S.</p> <p>1982-01-01</p> <p>Land subsidence due to ground-water overdraft in the San Joaquin <span class="hlt">Valley</span> began in the mid-1920 's and continued at alarming rates until surface was imported through major canals and aqueducts in the 1950 's and late 1960's. In areas where surface water replaced withdrawal of ground-water, water levels in the confined system rose sharply and subsidence slowed. In the late 1960 's and early 1970 's water levels in wells recovered to levels of the 1940 's and 1950 's throughout most of the western and southern parts of the <span class="hlt">Valley</span>, in response to the importation of surface water through the <span class="hlt">California</span> aqueduct. During the 1976-77 drought data collected at water-level and extensometer sites showed the effect of heavy demand on the ground-water resevoir. With the ' water of compaction ' gone, artesian head declined 10 to 20 times as fast as during the first cycle of long-term drawdown that ended in the late 1960's. In the 1978-79 water levels recovered to or above the 1976 pre-drought levels. The report suggests continued monitoring of land subsidence in the San Joaquin <span class="hlt">Valley</span>. (USGS)</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70047132','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70047132"><span>Structural evolution of the east Sierra <span class="hlt">Valley</span> system (Owens <span class="hlt">Valley</span> and vicinity), <span class="hlt">California</span>: a geologic and geophysical synthesis</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Stevens, Calvin H.; Stone, Paul; Blakely, Richard J.</p> <p>2013-01-01</p> <p>The tectonically active East Sierra <span class="hlt">Valley</span> System (ESVS), which comprises the westernmost part of the Walker Lane-Eastern <span class="hlt">California</span> Shear Zone, marks the boundary between the highly extended Basin and Range Province and the largely coherent Sierra Nevada-Great <span class="hlt">Valley</span> microplate (SN-GVm), which is moving relatively NW. The recent history of the ESVS is characterized by oblique extension partitioned between NNW-striking normal and strike-slip faults oriented at an angle to the more northwesterly relative motion of the SN-GVm. Spatially variable extension and right-lateral shear have resulted in a longitudinally segmented <span class="hlt">valley</span> system composed of diverse geomorphic and structural elements, including a discontinuous series of deep basins detected through analysis of isostatic gravity anomalies. Extension in the ESVS probably began in the middle Miocene in response to initial westward movement of the SN-GVm relative to the Colorado Plateau. At ca. 3-3.5 Ma, the SN-GVm became structurally separated from blocks directly to the east, resulting in significant basin-forming deformation in the ESVS. We propose a structural model that links high-angle normal faulting in the ESVS with coeval low-angle detachment faulting in adjacent areas to the east.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70024230','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70024230"><span>Timing of large <span class="hlt">earthquakes</span> since A.D. 800 on the Mission Creek strand of the San Andreas fault zone at Thousand Palms Oasis, near Palm Springs, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fumal, T.E.; Rymer, M.J.; Seitz, G.G.</p> <p>2002-01-01</p> <p>Paleoseismic investigations across the Mission Creek strand of the San Andreas fault at Thousand Palms Oasis indicate that four and probably five surface-rupturing <span class="hlt">earthquakes</span> occurred during the past 1200 years. Calendar age estimates for these <span class="hlt">earthquakes</span> are based on a chronological model that incorporates radio-carbon dates from 18 in situ burn layers and stratigraphic ordering constraints. These five <span class="hlt">earthquakes</span> occurred in about A.D. 825 (770-890) (mean, 95% range), A.D. 982 (840-1150), A.D. 1231 (1170-1290), A.D. 1502 (1450-1555), and after a date in the range of A.D. 1520-1680. The most recent surface-rupturing <span class="hlt">earthquake</span> at Thousand Palms is likely the same as the A.D. 1676 ?? 35 event at Indio reported by Sieh and Williams (1990). Each of the past five <span class="hlt">earthquakes</span> recorded on the San Andreas fault in the Coachella <span class="hlt">Valley</span> strongly overlaps in time with an event at the Wrightwood paleoseismic site, about 120 km northwest of Thousand Palms Oasis. Correlation of events between these two sites suggests that at least the southernmost 200 km of the San Andreas fault zone may have ruptured in each <span class="hlt">earthquake</span>. The average repeat time for surface-rupturing <span class="hlt">earthquakes</span> on the San Andreas fault in the Coachella <span class="hlt">Valley</span> is 215 ?? 25 years, whereas the elapsed time since the most recent event is 326 ?? 35 years. This suggests the southernmost San Andreas fault zone likely is very near failure. The Thousand Palms Oasis site is underlain by a series of six channels cut and filled since about A.D. 800 that cross the fault at high angles. A channel margin about 900 years old is offset right laterally 2.0 ?? 0.5 m, indicating a slip rate of 4 ?? 2 mm/yr. This slip rate is low relative to geodetic and other geologic slip rate estimates (26 ?? 2 mm/yr and about 23-35 mm/yr, respectively) on the southernmost San Andreas fault zone, possibly because (1) the site is located in a small step-over in the fault trace and so the rate is not be representative of the Mission Creek fault</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=perception+AND+risk&pg=7&id=EJ835537','ERIC'); return false;" href="https://eric.ed.gov/?q=perception+AND+risk&pg=7&id=EJ835537"><span>Pesticide Risk Communication, Risk Perception, and Self-Protective Behaviors among Farmworkers in <span class="hlt">California</span>'s Salinas <span class="hlt">Valley</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Cabrera, Nolan L.; Leckie, James O.</p> <p>2009-01-01</p> <p>Agricultural pesticide use is the highest of any industry, yet there is little research evaluating farmworkers' understandings of the health risks chemical exposure poses. This study examines pesticide education, risk perception, and self-protective behaviors among farmworkers in <span class="hlt">California</span>'s Salinas <span class="hlt">Valley</span>. Fifty current and former farmworkers…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/pp/pp1551/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/pp/pp1551/"><span>The Loma Prieta, <span class="hlt">California</span>, <span class="hlt">Earthquake</span> of October 17, 1989: Strong Ground Motion and Ground Failure</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Coordinated by Holzer, Thomas L.</p> <p>1992-01-01</p> <p>Professional Paper 1551 describes the effects at the land surface caused by the Loma Prieta <span class="hlt">earthquake</span>. These effects: include the pattern and characteristics of strong ground shaking, liquefaction of both floodplain deposits along the Pajaro and Salinas Rivers in the Monterey Bay region and sandy artificial fills along the margins of San Francisco Bay, landslides in the epicentral region, and increased stream flow. Some significant findings and their impacts were: * Strong shaking that was amplified by a factor of about two by soft soils caused damage at up to 100 kilometers (60 miles) from the epicenter. * Instrumental recordings of the ground shaking have been used to improve how building codes consider site amplification effects from soft soils. * Liquefaction at 134 locations caused $99.2 million of the total <span class="hlt">earthquake</span> loss of $5.9 billion. Liquefaction of floodplain deposits and sandy artificial fills was similar in nature to that which occurred in the 1906 San Francisco <span class="hlt">earthquake</span> and indicated that many areas remain susceptible to liquefaction damage in the San Francisco and Monterey Bay regions. * Landslides caused $30 million in <span class="hlt">earthquake</span> losses, damaging at least 200 residences. Many landslides showed evidence of movement in previous <span class="hlt">earthquakes</span>. * Recognition of the similarities between liquefaction and landslides in 1906 and 1989 and research in intervening years that established methodologies to map liquefaction and landslide hazards prompted the <span class="hlt">California</span> legislature to pass in 1990 the Seismic Hazards Mapping Act that required the <span class="hlt">California</span> Geological Survey to delineate regulatory zones of areas potentially susceptible to these hazards. * The <span class="hlt">earthquake</span> caused the flow of many streams in the epicentral region to increase. Effects were noted up to 88 km from the epicenter. * Post-<span class="hlt">earthquake</span> studies of the Marina District of San Francisco provide perhaps the most comprehensive case history of <span class="hlt">earthquake</span> effects at a specific site developed for</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29520761','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29520761"><span>Mapping Aquifer Systems with Airborne Electromagnetics in the Central <span class="hlt">Valley</span> of <span class="hlt">California</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Knight, Rosemary; Smith, Ryan; Asch, Ted; Abraham, Jared; Cannia, Jim; Viezzoli, Andrea; Fogg, Graham</p> <p>2018-03-09</p> <p>The passage of the Sustainable Groundwater Management Act in <span class="hlt">California</span> has highlighted a need for cost-effective ways to acquire the data used in building conceptual models of the aquifer systems in the Central <span class="hlt">Valley</span> of <span class="hlt">California</span>. One approach would be the regional implementation of the airborne electromagnetic (AEM) method. We acquired 104 line-kilometers of data in the Tulare Irrigation District, in the Central <span class="hlt">Valley</span>, to determine the depth of investigation (DOI) of the AEM method, given the abundance of electrically conductive clays, and to assess the usefulness of the method for mapping the hydrostratigraphy. The data were high quality providing, through inversion of the data, models displaying the variation in electrical resistivity to a depth of approximately 500 m. In order to transform the resistivity models to interpreted sections displaying lithology, we established the relationship between resistivity and lithology using collocated lithology logs (from drillers' logs) and AEM data. We modeled the AEM response and employed a bootstrapping approach to solve for the range of values in the resistivity model corresponding to sand and gravel, mixed coarse and fine, and clay in the unsaturated and saturated regions. The comparison between the resulting interpretation and an existing cross section demonstrates that AEM can be an effective method for mapping the large-scale hydrostratigraphy of aquifer systems in the Central <span class="hlt">Valley</span>. The methods employed and developed in this study have widespread application in the use of the AEM method for groundwater management in similar geologic settings. © 2018 The Authors. Groundwater published by Wiley Periodicals, Inc. on behalf of National Ground Water Association.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/0172-96/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/0172-96/report.pdf"><span>Invisible CO2 gas killing trees at Mammoth Mountain, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sorey, Michael L.; Farrar, Christopher D.; Evans, William C.; Hill, David P.; Bailey, Roy A.; Hendley, James W.; Stauffer, Peter H.</p> <p>1996-01-01</p> <p>Since 1980, scientists have monitored geologic unrest in Long <span class="hlt">Valley</span> Caldera and at adjacent Mammoth Mountain, <span class="hlt">California</span>. After a persistent swarm of <span class="hlt">earthquakes</span> beneath Mammoth Mountain in 1989, earth scientists discovered that large volumes of carbon dioxide (CO2) gas were seeping from beneath this volcano. This gas is killing trees on the mountain and also can be a danger to people. The USGS continues to study the CO2 emissions to help protect the public from this invisible potential hazard.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70018804','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70018804"><span>Optimal pumping strategies for managing shallow, poorquality groundwater, western San Joaquin <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Barlow, P.; Wagner, B.; Belitz, K.</p> <p>1995-01-01</p> <p>Continued agricultural productivity in the western San Joaquin <span class="hlt">Valley</span>, <span class="hlt">California</span>, is threatened by the presence of shallow, poor-quality groundwater that can cause soil salinization. We evaluate the management alternative of using groundwater pumping to control the altitude of the water table and provide irrigation water requirements. A transient, three-dimensional, groundwater flow model was linked with nonlinear optimization to simulate management alternatives for the groundwater flow system. Optimal pumping strategies have been determined that substantially reduce the area subject to a shallow water table and bare-soil evaporation (that is, areas with a water table within 2.1 m of land surface) and the rate of drainflow to on-farm drainage systems. Optimal pumping strategies are constrained by the existing distribution of wells between the semiconfined and confined zones of the aquifer, by the distribution of sediment types (and associated hydraulic conductivities) in the western <span class="hlt">valley</span>, and by the historical distribution of pumping throughout the western <span class="hlt">valley</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998JGR...103..869R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998JGR...103..869R"><span>Persistent water level changes in a well near Parkfield, <span class="hlt">California</span>, due to local and distant <span class="hlt">earthquakes</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Roeloffs, Evelyn A.</p> <p>1998-01-01</p> <p>Coseismic water level rises in the 30-m deep Bourdieu <span class="hlt">Valley</span> (BV) well near Parkfield, <span class="hlt">California</span>, have occurred in response to three local and five distant <span class="hlt">earthquakes</span>. Coseismic changes in static strain cannot explain these water level rises because (1) the well is insensitive to strain at tidal periods; (2) for the distant <span class="hlt">earthquakes</span>, the expected coseismic static strain is extremely small; and (3) the water level response is of the incorrect sign for the local <span class="hlt">earthquakes</span>. These water level changes must therefore be caused by seismic waves, but unlike seismic water level oscillations, they are monotonic, persist for days or weeks, and seem to be caused by waves with periods of several seconds rather than long-period surface waves. Other investigators have reported a similar phenomenon in Japan. Certain wells consistently exhibit this type of coseismic water level change, which is always in the same direction, regardless of the <span class="hlt">earthquake</span>'s azimuth or focal mechanism, and approximately proportional to the inverse square of hypocentral distance. To date, the coseismic water level rises in the B V well have never exceeded the seasonal water level maximum, although their sizes are relatively well correlated with <span class="hlt">earthquake</span> magnitude and distance. The frequency independence of the well's response to barometric pressure in the frequency band 0.1 to 0.7 cpd implies that the aquifer is fairly well confined. High aquifer compressibility, probably due to a gas phase in the pore space, is the most likely reason why the well does not respond to Earth tides. The phase and amplitude relationships between the seasonal water level and precipitation cycles constrain the horizontal hydraulic diffusivity to within a factor of 4.5, bounding hypothetical <span class="hlt">earthquake</span>-induced changes in aquifer hydraulic properties. Moreover, changes of hydraulic conductivity and/or diffusivity throughout the aquifer would not be expected to change the water level in the same direction at every time</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70020658','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70020658"><span>Persistent water level changes in a well near Parkfield, <span class="hlt">California</span>, due to local and distant <span class="hlt">earthquakes</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Roeloffs, E.A.</p> <p>1998-01-01</p> <p>Coseismic water level rises in the 30-m deep Bourdieu <span class="hlt">Valley</span> (BV) well near Parkfield, <span class="hlt">California</span>, have occurred in response to three local and five distant <span class="hlt">earthquakes</span>. Coseismic changes in static strain cannot explain these water level rises because (1) the well is insensitive to strain at tidal periods; (2) for the distant <span class="hlt">earthquakes</span>, the expected coseismic static strain is extremely small; and (3) the water level response is of the incorrect sign for the local <span class="hlt">earthquakes</span>. These water level changes must therefore be caused by seismic waves, but unlike seismic water level oscillations, they are monotonic, persist for days or weeks, and seem to be caused by waves with periods of several seconds rather than long-period surface waves. Other investigators have reported a similar phenomenon in Japan. Certain wells consistently exhibit this type of coseismic water level change, which is always in the same direction, regardless of the <span class="hlt">earthquake</span>'s azimuth or focal mechanism, and approximately proportional to the inverse square of hypocentral distance. To date, the coseismic water level rises in the BV well have never exceeded the seasonal water level maximum, although their sizes are relatively well correlated with <span class="hlt">earthquake</span> magnitude and distance. The frequency independence of the well's response to barometric pressure in the frequency band 0.1 to 0.7 cpd implies that the aquifer is fairly well confined. High aquifer compressibility, probably due to a gas phase in the pore space, is the most likely reason why the well does not respond to Earth tides. The phase and amplitude relationships between the seasonal water level and precipitation cycles constrain the horizontal hydraulic diffusivity to within a factor of 4.5, bounding hypothetical <span class="hlt">earthquake</span>-induced changes in aquifer hydraulic properties. Moreover, changes of hydraulic conductivity and/or diffusivity throughout the aquifer would not be expected to change the water level in the same direction at every time</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70018794','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70018794"><span>Stress/strain changes and triggered seismicity following the MW7.3 Landers, <span class="hlt">California</span>, <span class="hlt">earthquake</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Gomberg, J.</p> <p>1996-01-01</p> <p>Calculations of dynamic stresses and strains, constrained by broadband seismograms, are used to investigate their role in generating the remotely triggered seismicity that followed the June 28, 1992, MW7.3 Landers, <span class="hlt">California</span> <span class="hlt">earthquake</span>. I compare straingrams and dynamic Coulomb failure functions calculated for the Landers <span class="hlt">earthquake</span> at sites that did experience triggered seismicity with those at sites that did not. Bounds on triggering thresholds are obtained from analysis of dynamic strain spectra calculated for the Landers and MW,6.1 Joshua Tree, <span class="hlt">California</span>, <span class="hlt">earthquakes</span> at various sites, combined with results of static strain investigations by others. I interpret three principal results of this study with those of a companion study by Gomberg and Davis [this issue]. First, the dynamic elastic stress changes themselves cannot explain the spatial distribution of triggered seismicity, particularly the lack of triggered activity along the San Andreas fault system. In addition to the requirement to exceed a Coulomb failure stress level, this result implies the need to invoke and satisfy the requirements of appropriate slip instability theory. Second, results of this study are consistent with the existence of frequency- or rate-dependent stress/strain triggering thresholds, inferred from the companion study and interpreted in terms of <span class="hlt">earthquake</span> initiation involving a competition of processes, one promoting failure and the other inhibiting it. Such competition is also part of relevant instability theories. Third, the triggering threshold must vary from site to site, suggesting that the potential for triggering strongly depends on site characteristics and response. The lack of triggering along the San Andreas fault system may be correlated with the advanced maturity of its fault gouge zone; the strains from the Landers <span class="hlt">earthquake</span> were either insufficient to exceed its larger critical slip distance or some other critical failure parameter; or the faults failed stably as</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21785858','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21785858"><span>Prevalence of hepatitis B infection among young and unsuspecting Hmong blood donors in the Central <span class="hlt">California</span> <span class="hlt">Valley</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sheikh, Muhammad Y; Atla, Pradeep R; Raoufi, Rahim; Sadiq, Humaira; Sadler, Patrick C</p> <p>2012-02-01</p> <p>Chronic hepatitis B virus (HBV) infection may result in cirrhosis and/or hepatocellular carcinoma and is one of the leading causes of mortality in Asian Americans including Hmong Americans. The Central <span class="hlt">California</span> <span class="hlt">Valley</span> is home to a huge Hmong population. To date, the true prevalence of HBV among Hmong is largely unknown. The aim of this study was to contribute to the limited data on HBV prevalence and its trends in Hmong population in the Central <span class="hlt">California</span> <span class="hlt">Valley</span>. Between fiscal years 2006 and 2010, a total of 219, 450 voluntary donors were identified at Central <span class="hlt">California</span> Blood Center in Fresno. Of these, 821 (399 males and 422 females) were Hmong donors. A cross-sectional review of the HBV (hepatitis B surface antigen) positivity among all donors was carried out. Prevalence estimates with 95% confidence intervals (CI) were calculated. Ninety-two percent of Hmong donors were between age groups 16 and 35 years, and only 8% were ≥36 years. The overall prevalence in Hmong was noted at 3.41% (95%CI 2.3-4.9) compared to 0.06% (95%CI 0.05-0.07) in donors of all ethnicities. The calculated prevalence could be an underestimate of the true HBV prevalence in Hmong as the study enrolled only healthy blood donors with predominant younger age (≤35 years) population. These results underscore the persistent burden of HBV infection and potentially increased risk of premature death even in the second generation Hmong community of the Central <span class="hlt">California</span> <span class="hlt">Valley</span>. This study reemphasizes the unequivocal need to develop robust preventive and treatment strategies for HBV in Hmong community.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2007/1437/a/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2007/1437/a/"><span><span class="hlt">California</span> Fault Parameters for the National Seismic Hazard Maps and Working Group on <span class="hlt">California</span> <span class="hlt">Earthquake</span> Probabilities 2007</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wills, Chris J.; Weldon, Ray J.; Bryant, W.A.</p> <p>2008-01-01</p> <p>This report describes development of fault parameters for the 2007 update of the National Seismic Hazard Maps and the Working Group on <span class="hlt">California</span> <span class="hlt">Earthquake</span> Probabilities (WGCEP, 2007). These reference parameters are contained within a database intended to be a source of values for use by scientists interested in producing either seismic hazard or deformation models to better understand the current seismic hazards in <span class="hlt">California</span>. These parameters include descriptions of the geometry and rates of movements of faults throughout the state. These values are intended to provide a starting point for development of more sophisticated deformation models which include known rates of movement on faults as well as geodetic measurements of crustal movement and the rates of movements of the tectonic plates. The values will be used in developing the next generation of the time-independent National Seismic Hazard Maps, and the time-dependant seismic hazard calculations being developed for the WGCEP. Due to the multiple uses of this information, development of these parameters has been coordinated between USGS, CGS and SCEC. SCEC provided the database development and editing tools, in consultation with USGS, Golden. This database has been implemented in Oracle and supports electronic access (e.g., for on-the-fly access). A GUI-based application has also been developed to aid in populating the database. Both the continually updated 'living' version of this database, as well as any locked-down official releases (e.g., used in a published model for calculating <span class="hlt">earthquake</span> probabilities or seismic shaking hazards) are part of the USGS Quaternary Fault and Fold Database http://<span class="hlt">earthquake</span>.usgs.gov/regional/qfaults/ . CGS has been primarily responsible for updating and editing of the fault parameters, with extensive input from USGS and SCEC scientists.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.6014O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.6014O"><span>Multi-sensor Integration of Space and Ground Observations of Pre-<span class="hlt">earthquake</span> Anomalies Associated with M6.0, August 24, 2014 Napa, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ouzounov, Dimitar; Tramutoli, Valerio; Pulinets, Sergey; Liu, Tiger; Filizzola, Carolina; Genzano, Nicola; Lisi, Mariano; Petrov, Leonid; Kafatos, Menas</p> <p>2015-04-01</p> <p>We integrate multiple space-born and ground sensors for monitoring pre-<span class="hlt">earthquake</span> geophysical anomalies that can provide significant early notification for <span class="hlt">earthquakes</span> higher than M5.5 worldwide. The latest M6.0 event of August 24, 2014 in South Napa, <span class="hlt">California</span> generated pre-<span class="hlt">earthquake</span> signatures during our outgoing tests for <span class="hlt">California</span>, and an experimental warning was documented about 17 days in advance. We process in controlled environment different satellite and ground data for <span class="hlt">California</span> (and several other test areas) by using: a) data from the NPOES sensors recording OLR (Outgoing Longwave Radiation) in the infrared; b) 2/GNSS, FORMOSAT (GPS/TEC); c) Earth Observing System assimilation models from NASA; d) ground-based gas observations and meteorological data; e) TIR (Thermal Infrared) data from geostationary satellite (GOES). On Aug 4th, we detected (prospectively) a large anomaly of OLR transient field at the TOA over Northern <span class="hlt">California</span>. The location was shifted in the northeast direction about 150 km from the Aug 23rd epicentral area. Compared to the reference field of August 2004 to 2014 the hotspot anomaly was the largest energy flux anomaly over the entire continental United States at this time. Based on the temporal and spatial estimates of the anomaly, on August 4th we issued an internal warning for a M5.5+ <span class="hlt">earthquake</span> in Northern <span class="hlt">California</span> within the next 1-4 weeks. TIR retrospective analysis showed significant (spatially extended and temporally persistent) sequences of TIR anomalies starting August 1st just in the future epicenter area and approximately in the same area affected by OLR anomalies in the following days. GPS/TEC retrospective analysis based on GIM and TGIM products show anomalies TEC variations 1-3 days, over region north form the Napa <span class="hlt">earthquake</span> epicenter. The calculated index of atmospheric chemical potential based on the NASA numerical Assimilation weather model GEOS5 indicates for abnormal variations near the epicentral area days</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.S11B0578G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.S11B0578G"><span>Conditional Probabilities of Large <span class="hlt">Earthquake</span> Sequences in <span class="hlt">California</span> from the Physics-based Rupture Simulator RSQSim</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gilchrist, J. J.; Jordan, T. H.; Shaw, B. E.; Milner, K. R.; Richards-Dinger, K. B.; Dieterich, J. H.</p> <p>2017-12-01</p> <p>Within the SCEC Collaboratory for Interseismic Simulation and Modeling (CISM), we are developing physics-based forecasting models for <span class="hlt">earthquake</span> ruptures in <span class="hlt">California</span>. We employ the 3D boundary element code RSQSim (Rate-State <span class="hlt">Earthquake</span> Simulator of Dieterich & Richards-Dinger, 2010) to generate synthetic catalogs with tens of millions of events that span up to a million years each. This code models rupture nucleation by rate- and state-dependent friction and Coulomb stress transfer in complex, fully interacting fault systems. The Uniform <span class="hlt">California</span> <span class="hlt">Earthquake</span> Rupture Forecast Version 3 (UCERF3) fault and deformation models are used to specify the fault geometry and long-term slip rates. We have employed the Blue Waters supercomputer to generate long catalogs of simulated <span class="hlt">California</span> seismicity from which we calculate the forecasting statistics for large events. We have performed probabilistic seismic hazard analysis with RSQSim catalogs that were calibrated with system-wide parameters and found a remarkably good agreement with UCERF3 (Milner et al., this meeting). We build on this analysis, comparing the conditional probabilities of sequences of large events from RSQSim and UCERF3. In making these comparisons, we consider the epistemic uncertainties associated with the RSQSim parameters (e.g., rate- and state-frictional parameters), as well as the effects of model-tuning (e.g., adjusting the RSQSim parameters to match UCERF3 recurrence rates). The comparisons illustrate how physics-based rupture simulators might assist forecasters in understanding the short-term hazards of large aftershocks and multi-event sequences associated with complex, multi-fault ruptures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/767622','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/767622"><span>Water resources development in Santa Clara <span class="hlt">Valley</span>, <span class="hlt">California</span>: insights into the human-hydrologic relationship</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Reynolds, Jesse L.</p> <p>2000-06-01</p> <p>Groundwater irrigation is critical to food production and, in turn, to humankind's relationship with its environment. The development of groundwater in Santa Clara <span class="hlt">Valley</span>, <span class="hlt">California</span> during the early twentieth century is instructive because (1) responses to unsustainable resource use were largely successful; (2) the proposals for the physical management of the water, although not entirely novel, incorporated new approaches which reveal an evolving relationship between humans and the hydrologic cycle; and (3) the <span class="hlt">valley</span> serves as a natural laboratory where natural (groundwater basin, surface watershed) and human (county, water district) boundaries generally coincide. Here, I investigate how water resources developmentmore » and management in Santa Clara <span class="hlt">Valley</span> was influenced by, and reflective of, a broad understanding of water as a natural resource, including scientific and technological innovations, new management approaches, and changing perceptions of the hydrologic cycle. Market demands and technological advances engendered reliance on groundwater. This, coupled with a series of dry years and laissez faire government policies, led to overdraft. Faith in centralized management and objective engineering offered a solution to concerns over resource depletion, and a group dominated by orchardists soon organized, fought for a water conservation district, and funded an investigation to halt the decline of well levels. Engineer Fred Tibbetts authored an elaborate water salvage and recharge plan that optimized the local water resources by integrating multiple components of the hydrologic cycle. Informed by government investigations, groundwater development in Southern <span class="hlt">California</span>, and local water law cases, it recognized the limited surface storage possibilities, the spatial and temporal variability, the relatively closed local hydrology, the interconnection of surface and subsurface waters, and the value of the groundwater basin for its storage, transportation, and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA02795&hterms=time+perspective&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dtime%2Bperspective','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA02795&hterms=time+perspective&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dtime%2Bperspective"><span>SRTM Perspective View with Landsat Overlay: Caliente Range and Cuyama <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2001-01-01</p> <p>Before the arrival of Europeans, <span class="hlt">California</span>'s Cuyama <span class="hlt">Valley</span> was inhabited by Native Americans who were culturally and politically tied to the Chumash tribes of coastal Santa Barbara County. Centuries later, the area remains the site of noted Native American rock art paintings. In the 1800s, when Europeans established large cattle and horse-breeding ranches in the <span class="hlt">valley</span>, the early settlers reported the presence of small villages along the Cuyama River. This perspective view looks upstream toward the southeast through the Cuyama <span class="hlt">Valley</span>. The Caliente Range, with maximum elevations of 1,550 meters (5,085 feet), borders the <span class="hlt">valley</span> on the left. The Cuyama River, seen as a bright meandering line on the <span class="hlt">valley</span> floor, enters the <span class="hlt">valley</span> from headwaters more than 2,438 meters (8,000 feet) above sea level near Mount Abel and flows 154 kilometers (96 miles) before emptying into the Pacific Ocean. The river's course has been determined in large part by displacement along numerous faults.<p/>Today, the Cuyama <span class="hlt">Valley</span> is the home of large ranches and small farms. The area has a population of 1,120 and is more than an hour and a half drive from the nearest city in the county.<p/>This image was generated by draping an enhanced Landsat satellite image over elevation data from the Shuttle Radar Topography Mission (SRTM). Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter resolution of most Landsat images and will substantially help in analyses of the large and growing Landsat image archive. For visualization purposes, topographic heights displayed in this image are exaggerated two times. Colors approximate natural colors.<p/>The elevation data used in this image was acquired by SRTM aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on Endeavour in 1994. SRTM</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title27-vol1/pdf/CFR-2011-title27-vol1-sec9-194.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title27-vol1/pdf/CFR-2011-title27-vol1-sec9-194.pdf"><span>27 CFR 9.194 - San Antonio <span class="hlt">Valley</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-04-01</p> <p>... significance. (b) Approved Maps. The appropriate maps for determining the boundary of the San Antonio <span class="hlt">Valley</span>...) Hames <span class="hlt">Valley</span>, <span class="hlt">California</span>, 1949, photorevised 1978; (2) Tierra Redonda Mountain, <span class="hlt">California</span>, 1949... southeast corner of section 14, T23S, R9E, on the Hames <span class="hlt">Valley</span> map; (2) From the beginning point, proceed...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRB..120.5013M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRB..120.5013M"><span>Seismogeodesy of the 2014 Mw6.1 Napa <span class="hlt">earthquake</span>, <span class="hlt">California</span>: Rapid response and modeling of fast rupture on a dipping strike-slip fault</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Melgar, Diego; Geng, Jianghui; Crowell, Brendan W.; Haase, Jennifer S.; Bock, Yehuda; Hammond, William C.; Allen, Richard M.</p> <p>2015-07-01</p> <p>Real-time high-rate geodetic data have been shown to be useful for rapid <span class="hlt">earthquake</span> response systems during medium to large events. The 2014 Mw6.1 Napa, <span class="hlt">California</span> <span class="hlt">earthquake</span> is important because it provides an opportunity to study an event at the lower threshold of what can be detected with GPS. We show the results of GPS-only <span class="hlt">earthquake</span> source products such as peak ground displacement magnitude scaling, centroid moment tensor (CMT) solution, and static slip inversion. We also highlight the retrospective real-time combination of GPS and strong motion data to produce seismogeodetic waveforms that have higher precision and longer period information than GPS-only or seismic-only measurements of ground motion. We show their utility for rapid kinematic slip inversion and conclude that it would have been possible, with current real-time infrastructure, to determine the basic features of the <span class="hlt">earthquake</span> source. We supplement the analysis with strong motion data collected close to the source to obtain an improved postevent image of the source process. The model reveals unilateral fast propagation of slip to the north of the hypocenter with a delayed onset of shallow slip. The source model suggests that the multiple strands of observed surface rupture are controlled by the shallow soft sediments of Napa <span class="hlt">Valley</span> and do not necessarily represent the intersection of the main faulting surface and the free surface. We conclude that the main dislocation plane is westward dipping and should intersect the surface to the east, either where the easternmost strand of surface rupture is observed or at the location where the West Napa fault has been mapped in the past.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70073949','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70073949"><span>Common features and peculiarities of the seismic activity at Phlegraean Fields, Long <span class="hlt">Valley</span>, and Vesuvius</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Marzocchi, W.; Vilardo, G.; Hill, D.P.; Ricciardi, G.P.; Ricco, C.</p> <p>2001-01-01</p> <p>We analyzed and compared the seismic activity that has occurred in the last two to three decades in three distinct volcanic areas: Phlegraean Fields, Italy; Vesuvius, Italy; and Long <span class="hlt">Valley</span>, <span class="hlt">California</span>. Our main goal is to identify and discuss common features and peculiarities in the temporal evolution of <span class="hlt">earthquake</span> sequences that may reflect similarities and differences in the generating processes between these volcanic systems. In particular, we tried to characterize the time series of the number of events and of the seismic energy release in terms of stochastic, deterministic, and chaotic components. The time sequences from each area consist of thousands of <span class="hlt">earthquakes</span> that allow a detailed quantitative analysis and comparison. The results obtained showed no evidence for either deterministic or chaotic components in the <span class="hlt">earthquake</span> sequences in Long <span class="hlt">Valley</span> caldera, which appears to be dominated by stochastic behavior. In contrast, <span class="hlt">earthquake</span> sequences at Phlegrean Fields and Mount Vesuvius show a deterministic signal mainly consisting of a 24-hour periodicity. Our analysis suggests that the modulation in seismicity is in some way related to thermal diurnal processes, rather than luni-solar tidal effects. Independently from the process that generates these periodicities on the seismicity., it is suggested that the lack (or presence) of diurnal cycles is seismic swarms of volcanic areas could be closely linked to the presence (or lack) of magma motion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70178688','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70178688"><span>Potential effects of drought on carrying capacity for wintering waterfowl in the Central <span class="hlt">Valley</span> of <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Petrie, Mark J.; Fleskes, Joseph P.; Wolder, Mike A.; Isola, Craig R.; Yarris, Gregory S.; Skalos, Daniel A.</p> <p>2016-01-01</p> <p>We used the bioenergetics model TRUEMET to evaluate potential effects of <span class="hlt">California</span>'s recent drought on food supplies for waterfowl wintering in the Central <span class="hlt">Valley</span> under a range of habitat and waterfowl population scenarios. In nondrought years in the current Central <span class="hlt">Valley</span> landscape, food supplies are projected to be adequate for waterfowl from fall through early spring (except late March) even if waterfowl populations reach North American Waterfowl Management Plan goals. However, in all drought scenarios that we evaluated, food supplies were projected to be exhausted for ducks by mid- to late winter and by late winter or early spring for geese. For ducks, these results were strongly related to projected declines in winter-flooded rice fields that provide 45% of all the food energy available to ducks in the Central <span class="hlt">Valley</span> in nondrought water years. Delayed flooding of some managed wetlands may help alleviate food shortages by providing wetland food resources better timed with waterfowl migration and abundance patterns in the Central <span class="hlt">Valley</span>, as well as reducing the amount of water needed to manage these habitats. However, future research is needed to evaluate the impacts of delayed flooding on waterfowl hunting, and whether <span class="hlt">California</span>'s existing water delivery system would make delayed flooding feasible. Securing adequate water supplies for waterfowl and other wetland-dependent birds is among the greatest challenges facing resource managers in coming years, especially in the increasingly arid western United States.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70168594','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70168594"><span>Seismology program; <span class="hlt">California</span> Division of Mines and Geology</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sherburne, R. W.</p> <p>1981-01-01</p> <p>The year 1980 marked the centennial of the <span class="hlt">California</span> Division of Mines and Geology (CDMG) and a decade of the Division's involvement in seismology. Factors which contributed to the formation of a Seismology Group within CDMG included increased concerns for environmental and <span class="hlt">earthquake</span> safety, interest in <span class="hlt">earthquake</span> prediction, the 1971 San Fernando <span class="hlt">earthquake</span> and the 1973 publication by CDMG of an urban geology master plan for <span class="hlt">California</span>. Reasons to be concerned about <span class="hlt">California</span>'s <span class="hlt">earthquake</span> problem are demonstrated by the accompanying table and the figures. Recent seismicity in <span class="hlt">California</span>, the Southern <span class="hlt">California</span> uplift reflecting changes in crustal strain, and other possible <span class="hlt">earthquake</span> precursors have heightened concern among scientific and governmental groups about the possible occurrence of a major damaging <span class="hlt">earthquake</span> )M>7) in <span class="hlt">California</span>. </p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2011-06-16/pdf/2011-15000.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2011-06-16/pdf/2011-15000.pdf"><span>76 FR 35167 - Revisions to the <span class="hlt">California</span> State Implementation Plan, San Joaquin <span class="hlt">Valley</span> Unified Air Pollution...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2011-06-16</p> <p>... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 52 [EPA-R09-OAR-2011-0312; FRL-9319-8] Revisions to the <span class="hlt">California</span> State Implementation Plan, San Joaquin <span class="hlt">Valley</span> Unified Air Pollution Control District... Subjects in 40 CFR Part 52 Environmental protection, Air pollution control, Intergovernmental relations...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/1988/4003/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/1988/4003/report.pdf"><span>Preliminary evaluation of the hydrogeologic system in Owens <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Danskin, W.R.</p> <p>1988-01-01</p> <p>A preliminary, two-layer, steady-state, groundwater flow model was used to evaluate present data and hydrologic concepts of Owens <span class="hlt">Valley</span>, <span class="hlt">California</span>. Simulations of the groundwater system indicate that areas where water levels are most affected by changes in recharge and discharge are near toes of alluvial fans and along the edge of permeable volcanic deposits. Sensitivity analysis for each model parameter shows that steady state simulations are most sensitive to uncertainties in evapotranspiration rates. Tungsten Hills, Poverty Hills, and Alabama Hills were found to act as virtually impermeable barriers to groundwater flow. Accurate simulation of the groundwater system between Bishop and Lone Pine appears to be possible without simulating the groundwater system in Round <span class="hlt">Valley</span>, near Owens Lake, or in aquifer materials more than 1,000 ft below land surface. Although vast amounts of geologic and hydrologic data have been collected for Owens <span class="hlt">Valley</span>, many parts of the hydrogeologic system have not been defined with sufficient detail to answer present water management questions. Location and extent of geologic materials that impede the vertical movement of water are poorly documented. The likely range of aquifer characteristics, except vertical hydraulic conductivity, is well known, but spatial distribution of these characteristics is not well documented. A set of consistent water budgets is needed, including one for surface water, groundwater, and the entire <span class="hlt">valley</span>. The largest component of previous water budgets (evapotranspiration) is largely unverified. More definitive estimates of local gains and losses for Owens River are needed. Although groundwater pumpage from each well is measured, the quantity of withdrawal from different zones of permeable material has not been defined. (USGS)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70037204','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70037204"><span>Abundance and sexual size dimorphism of the giant gartersnake (Thamnophis gigas) in the Sacramento <span class="hlt">valley</span> of <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wylie, G.D.; Casazza, Michael L.; Gregory, C.J.; Halstead, B.J.</p> <p>2010-01-01</p> <p>The Giant Gartersnake (Thamnophis gigas) is restricted to wetlands of the Central <span class="hlt">Valley</span> of <span class="hlt">California</span>. Because of wetland loss in this region, the Giant Gartersnake is both federally and state listed as threatened. We conducted markrecapture studies of four populations of the Giant Gartersnake in the Sacramento <span class="hlt">Valley</span> (northern Central <span class="hlt">Valley</span>), <span class="hlt">California</span>, to obtain baseline data on abundance and density to assist in recovery planning for this species. We sampled habitats that ranged from natural, unmanaged marsh to constructed managed marshes and habitats associated with rice agriculture. Giant Gartersnake density in a natural wetland (1.90 individuals/ha) was an order of magnitude greater than in a managed wetland subject to active season drying (0.17 individuals/ha). Sex ratios at all sites were not different from 1 1, and females were longer and heavier than males. Females had greater body condition than males, and individuals at the least disturbed sites had significantly greater body condition than individuals at the managed wetland. The few remaining natural wetlands in the Central <span class="hlt">Valley</span> are important, productive habitat for the Giant Gartersnake, and should be conserved and protected. Wetlands constructed and restored for the Giant Gartersnake should be modeled after the permanent, shallow wetlands representative of historic Giant Gartersnake habitat. ?? 2010 Society for the Study of Amphibians and Reptiles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70046870','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70046870"><span>Geometry and <span class="hlt">earthquake</span> potential of the shoreline fault, central <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hardebeck, Jeanne L.</p> <p>2013-01-01</p> <p>The Shoreline fault is a vertical strike‐slip fault running along the coastline near San Luis Obispo, <span class="hlt">California</span>. Much is unknown about the Shoreline fault, including its slip rate and the details of its geometry. Here, I study the geometry of the Shoreline fault at seismogenic depth, as well as the adjacent section of the offshore Hosgri fault, using seismicity relocations and <span class="hlt">earthquake</span> focal mechanisms. The Optimal Anisotropic Dynamic Clustering (OADC) algorithm (Ouillon et al., 2008) is used to objectively identify the simplest planar fault geometry that fits all of the <span class="hlt">earthquakes</span> to within their location uncertainty. The OADC results show that the Shoreline fault is a single continuous structure that connects to the Hosgri fault. Discontinuities smaller than about 1 km may be undetected, but would be too small to be barriers to <span class="hlt">earthquake</span> rupture. The Hosgri fault dips steeply to the east, while the Shoreline fault is essentially vertical, so the Hosgri fault dips towards and under the Shoreline fault as the two faults approach their intersection. The focal mechanisms generally agree with pure right‐lateral strike‐slip on the OADC planes, but suggest a non‐planar Hosgri fault or another structure underlying the northern Shoreline fault. The Shoreline fault most likely transfers strike‐slip motion between the Hosgri fault and other faults of the Pacific–North America plate boundary system to the east. A hypothetical <span class="hlt">earthquake</span> rupturing the entire known length of the Shoreline fault would have a moment magnitude of 6.4–6.8. A hypothetical <span class="hlt">earthquake</span> rupturing the Shoreline fault and the section of the Hosgri fault north of the Hosgri–Shoreline junction would have a moment magnitude of 7.2–7.5.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EP%26S...69...97B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EP%26S...69...97B"><span>Estimation of 1-D velocity models beneath strong-motion observation sites in the Kathmandu <span class="hlt">Valley</span> using strong-motion records from moderate-sized <span class="hlt">earthquakes</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bijukchhen, Subeg M.; Takai, Nobuo; Shigefuji, Michiko; Ichiyanagi, Masayoshi; Sasatani, Tsutomu; Sugimura, Yokito</p> <p>2017-07-01</p> <p>The Himalayan collision zone experiences many seismic activities with large <span class="hlt">earthquakes</span> occurring at certain time intervals. The damming of the proto-Bagmati River as a result of rapid mountain-building processes created a lake in the Kathmandu <span class="hlt">Valley</span> that eventually dried out, leaving thick unconsolidated lacustrine deposits. Previous studies have shown that the sediments are 600 m thick in the center. A location in a seismically active region, and the possible amplification of seismic waves due to thick sediments, have made Kathmandu <span class="hlt">Valley</span> seismically vulnerable. It has suffered devastation due to <span class="hlt">earthquakes</span> several times in the past. The development of the Kathmandu <span class="hlt">Valley</span> into the largest urban agglomerate in Nepal has exposed a large population to seismic hazards. This vulnerability was apparent during the Gorkha <span class="hlt">Earthquake</span> (Mw7.8) on April 25, 2015, when the main shock and ensuing aftershocks claimed more than 1700 lives and nearly 13% of buildings inside the <span class="hlt">valley</span> were completely damaged. Preparing safe and up-to-date building codes to reduce seismic risk requires a thorough study of ground motion amplification. Characterizing subsurface velocity structure is a step toward achieving that goal. We used the records from an array of strong-motion accelerometers installed by Hokkaido University and Tribhuvan University to construct 1-D velocity models of station sites by forward modeling of low-frequency S-waves. Filtered records (0.1-0.5 Hz) from one of the accelerometers installed at a rock site during a moderate-sized (mb4.9) <span class="hlt">earthquake</span> on August 30, 2013, and three moderate-sized (Mw5.1, Mw5.1, and Mw5.5) aftershocks of the 2015 Gorkha <span class="hlt">Earthquake</span> were used as input motion for modeling of low-frequency S-waves. We consulted available geological maps, cross-sections, and borehole data as the basis for initial models for the sediment sites. This study shows that the basin has an undulating topography and sediment sites have deposits of varying thicknesses</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70025513','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70025513"><span>Summary of recent research in Long <span class="hlt">Valley</span> Caldera, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sorey, M.L.; McConnell, V.S.; Roeloffs, E.</p> <p>2003-01-01</p> <p>Since 1978, volcanic unrest in the form of <span class="hlt">earthquakes</span> and ground deformation has persisted in the Long <span class="hlt">Valley</span> caldera and adjacent parts of the Sierra Nevada. The papers in this special volume focus on periods of accelerated seismicity and deformation in 1980, 1983, 1989-1990, and 1997-1998 to delineate relations between geologic, tectonic, and hydrologic processes. The results distinguish between <span class="hlt">earthquake</span> sequences that result from relaxation of existing stress accumulation through brittle failure and those in which brittle failure is driven by active intrusion. They also indicate that in addition to a relatively shallow (7-10-km) source beneath the resurgent dome, there exists a deeper (???15-km) source beneath the south moat. Analysis of microgravimety and deformation data indicates that the composition of the shallower source may involve a combination of silicic magma and hydrothermal fluid. Pressure and temperature fluctuations in wells have accompanied periods of crustal unrest, and additional pressure and temperature changes accompanying ongoing geothermal power production have resulted in land subsidence. The completion in 1998 of a 3000-m-deep drill hole on the resurgent dome has provided useful information on present and past periods of circulation of water at temperatures of 100-200??C within the crystalline basement rocks that underlie the post-caldera volcanics. The well is now being converted to a permanent geophysical monitoring station. ?? 2003 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/pp/pp1550/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/pp/pp1550/"><span>The Loma Prieta, <span class="hlt">California</span>, <span class="hlt">Earthquake</span> of October 17, 1989: <span class="hlt">Earthquake</span> Occurrence</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Coordinated by Bakun, William H.; Prescott, William H.</p> <p>1993-01-01</p> <p>Professional Paper 1550 seeks to understand the M6.9 Loma Prieta <span class="hlt">earthquake</span> itself. It examines how the fault that generated the <span class="hlt">earthquake</span> ruptured, searches for and evaluates precursors that may have indicated an <span class="hlt">earthquake</span> was coming, reviews forecasts of the <span class="hlt">earthquake</span>, and describes the geology of the <span class="hlt">earthquake</span> area and the crustal forces that affect this geology. Some significant findings were: * Slip during the <span class="hlt">earthquake</span> occurred on 35 km of fault at depths ranging from 7 to 20 km. Maximum slip was approximately 2.3 m. The <span class="hlt">earthquake</span> may not have released all of the strain stored in rocks next to the fault and indicates a potential for another damaging <span class="hlt">earthquake</span> in the Santa Cruz Mountains in the near future may still exist. * The <span class="hlt">earthquake</span> involved a large amount of uplift on a dipping fault plane. Pre-<span class="hlt">earthquake</span> conventional wisdom was that large <span class="hlt">earthquakes</span> in the Bay area occurred as horizontal displacements on predominantly vertical faults. * The fault segment that ruptured approximately coincided with a fault segment identified in 1988 as having a 30% probability of generating a M7 <span class="hlt">earthquake</span> in the next 30 years. This was one of more than 20 relevant <span class="hlt">earthquake</span> forecasts made in the 83 years before the <span class="hlt">earthquake</span>. * Calculations show that the Loma Prieta <span class="hlt">earthquake</span> changed stresses on nearby faults in the Bay area. In particular, the <span class="hlt">earthquake</span> reduced stresses on the Hayward Fault which decreased the frequency of small <span class="hlt">earthquakes</span> on it. * Geological and geophysical mapping indicate that, although the San Andreas Fault can be mapped as a through going fault in the epicentral region, the southwest dipping Loma Prieta rupture surface is a separate fault strand and one of several along this part of the San Andreas that may be capable of generating <span class="hlt">earthquakes</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/fs172-96/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/fs172-96/"><span>Invisible CO2 gas killing trees at Mammoth Mountain, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sorey, Michael L.; Farrar, Christopher D.; Gerlach, Terrance M.; McGee, Kenneth A.; Evans, William C.; Colvard, Elizabeth M.; Hill, David P.; Bailey, Roy A.; Rogie, John D.; Hendley, James W.; Stauffer, Peter H.</p> <p>2000-01-01</p> <p>Since 1980, scientists have monitored geologic unrest in Long <span class="hlt">Valley</span> Caldera and at adjacent Mammoth Mountain, <span class="hlt">California</span>. After a persistent swarm of <span class="hlt">earthquakes</span> beneath Mammoth Mountain in 1989, geologists discovered that large volumes of carbon dioxide (CO2 ) gas were seeping from beneath this volcano. This gas is killing trees on the mountain and also can be a danger to people. The U.S. Geological Survey (USGS) continues to study the CO2 emissions to help protect the public from this invisible potential hazard.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70035505','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70035505"><span>Recent developments in understanding the tectonic evolution of the Southern <span class="hlt">California</span> offshore area: Implications for <span class="hlt">earthquake</span>-hazard analysis</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fisher, M.A.; Langenheim, V.E.; Nicholson, C.; Ryan, H.F.; Sliter, R.W.</p> <p>2009-01-01</p> <p>During late Mesozoic and Cenozoic time, three main tectonic episodes affected the Southern <span class="hlt">California</span> offshore area. Each episode imposed its unique structural imprint such that early-formed structures controlled or at least influenced the location and development of later ones. This cascaded structural inheritance greatly complicates analysis of the extent, orientation, and activity of modern faults. These fault attributes play key roles in estimates of <span class="hlt">earthquake</span> magnitude and recurrence interval. Hence, understanding the <span class="hlt">earthquake</span> hazard posed by offshore and coastal faults requires an understanding of the history of structural inheritance and modifi-cation. In this report we review recent (mainly since 1987) findings about the tectonic development of the Southern <span class="hlt">California</span> offshore area and use analog models of fault deformation as guides to comprehend the bewildering variety of offshore structures that developed over time. This report also provides a background in regional tectonics for other chapters in this section that deal with the threat from offshore geologic hazards in Southern <span class="hlt">California</span>. ?? 2009 The Geological Society of America.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2018/3026/fs20183026_v1.1.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2018/3026/fs20183026_v1.1.pdf"><span>Groundwater quality in the shallow aquifers of the Monterey Bay, Salinas <span class="hlt">Valley</span>, and adjacent highland areas, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Burton, Carmen</p> <p>2018-05-30</p> <p>Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of <span class="hlt">California</span> created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. The shallow aquifers of the groundwater basins around Monterey Bay, the Salinas <span class="hlt">Valley</span>, and the highlands adjacent to the Salinas <span class="hlt">Valley</span> constitute one of the study units.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/sim/3377/sim3377.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sim/3377/sim3377.pdf"><span>Predicted pH at the domestic and public supply drinking water depths, Central <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Rosecrans, Celia Z.; Nolan, Bernard T.; Gronberg, Jo Ann M.</p> <p>2017-03-08</p> <p>This scientific investigations map is a product of the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) project modeling and mapping team. The prediction grids depicted in this map are of continuous pH and are intended to provide an understanding of groundwater-quality conditions at the domestic and public supply drinking water zones in the groundwater of the Central <span class="hlt">Valley</span> of <span class="hlt">California</span>. The chemical quality of groundwater and the fate of many contaminants is often influenced by pH in all aquifers. These grids are of interest to water-resource managers, water-quality researchers, and groundwater modelers concerned with the occurrence of natural and anthropogenic contaminants related to pH. In this work, the median well depth categorized as domestic supply was 30 meters below land surface, and the median well depth categorized as public supply is 100 meters below land surface. Prediction grids were created using prediction modeling methods, specifically boosted regression trees (BRT) with a Gaussian error distribution within a statistical learning framework within the computing framework of R (http://www.r-project.org/). The statistical learning framework seeks to maximize the predictive performance of machine learning methods through model tuning by cross validation. The response variable was measured pH from 1,337 wells and was compiled from two sources: USGS National Water Information System (NWIS) database (all data are publicly available from the USGS: http://waterdata.usgs.gov/ca/nwis/nwis) and the <span class="hlt">California</span> State Water Resources Control Board Division of Drinking Water (SWRCB-DDW) database (water quality data are publicly available from the SWRCB: http://www.waterboards.ca.gov/gama/geotracker_gama.shtml). Only wells with measured pH and well depth data were selected, and for wells with multiple records, only the most recent sample in the period 1993–2014 was used. A total of 1,003 wells (training dataset) were used to train the BRT</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23216262','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23216262"><span>Hospital compliance with a state unfunded mandate: the case of <span class="hlt">California</span>'s <span class="hlt">Earthquake</span> Safety Law.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McCue, Michael J; Thompson, Jon M</p> <p>2012-01-01</p> <p>Abstract In recent years, community hospitals have experienced heightened regulation with many unfunded mandates. The authors assessed the market, organizational, operational, and financial characteristics of general acute care hospitals in <span class="hlt">California</span> that have a main acute care hospital building that is noncompliant with state requirements and at risk of major structural collapse from <span class="hlt">earthquakes</span>. Using <span class="hlt">California</span> hospital data from 2007 to 2009, and employing logistic regression analysis, the authors found that hospitals having buildings that are at the highest risk of collapse are located in larger population markets, possess smaller market share, have a higher percentage of Medicaid patients, and have less liquidity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.A32B..09G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.A32B..09G"><span>New observations of VOC emissions and concentrations in, above, and around the Central <span class="hlt">Valley</span> of <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goldstein, A. H.; Fares, S.; Gentner, D. R.; Park, J.; Weber, R.; Ormeno, E.; Holzinger, R.; Misztal, P. K.; Karl, T. R.; Guenther, A. B.; Fischer, M. L.; Harley, R. A.; Karlik, J. F.</p> <p>2011-12-01</p> <p>Large portions of the Central <span class="hlt">Valley</span> of <span class="hlt">California</span> are out of compliance with current state and federal air quality standards for ozone and particulate matter, and the relative importance of biogenic and anthropogenic VOC emissions to their photochemical production in this region remains uncertain. In 2009-2011 multiple measurement campaigns were completed investigating the VOC emission inventory and concentration distributions. In 2009 BVOC emissions from more than 20 species of major agricultural crops in <span class="hlt">California</span> were measured in a greenhouse using branch enclosures by both PTRMS and in-situ GC. Overall, crops were found to emit low amounts of BVOC compared to the natural forests surrounding the <span class="hlt">valley</span>. Crops mainly emitted methanol and terpenes, with a broad array of other species emitted at lower levels, and all the measured crops showed negligible emissions of isoprene. Navel oranges were the largest crop BVOC emitters measured so a full year of flux measurements were made in an orange grove near Visalia in 2010 by eddy covariance(EC)-PTRMS with two multi-week periods of concentration measurements by hourly in-situ GC, and one month of high mass resolution flux measurements by EC-PTR-TOF-MS. The dominant BVOC emissions from the orange grove were methanol and terpenes, followed by acetone, acetaldehyde, and a low level of emissions for many other species. In 2011 aircraft eddy covariance measurements of BVOC fluxes were made by EC-PTRMS covering a large area of <span class="hlt">California</span> as part of the <span class="hlt">California</span> Airborne Bvoc Emission Research in Natural Ecosystem Transects (CABERNET) campaign aimed at improving BVOC emission models on regional scales, mainly profiling BVOC emissions from oak woodlands surrounding the Central <span class="hlt">Valley</span>. In 2010, hourly in-situ VOC measurements were made via in-situ GC in Bakersfield, CA as part of the CalNex experiment. Additionally, in-situ measurements of fresh motor vehicle exhaust were made in Oakland's Caldecott tunnel. Measurements by</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFMED13A1213P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFMED13A1213P"><span>The Southern <span class="hlt">California</span> <span class="hlt">Earthquake</span> Center/Undergraduate Studies in <span class="hlt">Earthquake</span> Information Technology (SCEC/UseIT) Internship Program</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Perry, S.; Jordan, T.</p> <p>2006-12-01</p> <p>Our undergraduate research program, SCEC/UseIT, an NSF Research Experience for Undergraduates site, provides software for <span class="hlt">earthquake</span> researchers and educators, movies for outreach, and ways to strengthen the technical career pipeline. SCEC/UseIT motivates diverse undergraduates towards science and engineering careers through team-based research in the exciting field of <span class="hlt">earthquake</span> information technology. UseIT provides the cross-training in computer science/information technology (CS/IT) and geoscience needed to make fundamental progress in <span class="hlt">earthquake</span> system science. Our high and increasing participation of women and minority students is crucial given the nation"s precipitous enrollment declines in CS/IT undergraduate degree programs, especially among women. UseIT also casts a "wider, farther" recruitment net that targets scholars interested in creative work but not traditionally attracted to summer science internships. Since 2002, SCEC/UseIT has challenged 79 students in three dozen majors from as many schools with difficult, real-world problems that require collaborative, interdisciplinary solutions. Interns design and engineer open-source software, creating increasingly sophisticated visualization tools (see "SCEC-VDO," session IN11), which are employed by SCEC researchers, in new curricula at the University of Southern <span class="hlt">California</span>, and by outreach specialists who make animated movies for the public and the media. SCEC-VDO would be a valuable tool for research-oriented professional development programs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/7090976-spatio-temporal-variation-seismicity-before-san-fernando-earthquake-california','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/7090976-spatio-temporal-variation-seismicity-before-san-fernando-earthquake-california"><span>Spatio-temporal variation of seismicity before the 1971 San Fernando <span class="hlt">earthquake</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Ishida, M.; Kanamori, H.</p> <p>1977-08-01</p> <p>The spatio-temporal variation of seismicity prior to the 1971 San Fernando, <span class="hlt">California</span>, <span class="hlt">earthquake</span> is studied for the area within 35 km of the epicenter. During the period from 1932 to 1961, the seismicity in this area was relatively low and random. A remarkable NE-SW trending alignment of activity occurred during the period from 1961 to 1964, the period corresponding to the inferred onset of the Palmdale uplift. During the period from 1965 to 1968, the seismicity around the epicentral area became extremely low; no event was located within 13 km from the epicenter. During the period from 1969 to themore » occurrence of the San Fernando <span class="hlt">earthquake</span>, activity around the epicentral area increased. This activity may be considered to be foreshock activity in a broad sense.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70041343','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70041343"><span>Remotely triggered microearthquakes and tremor in central <span class="hlt">California</span> following the 2010 Mw 8.8 Chile <span class="hlt">earthquake</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Peng, Zhigang; Hill, David P.; Shelly, David R.; Aiken, Chastity</p> <p>2010-01-01</p> <p>We examine remotely triggered microearthquakes and tectonic tremor in central <span class="hlt">California</span> following the 2010 Mw 8.8 Chile <span class="hlt">earthquake</span>. Several microearthquakes near the Coso Geothermal Field were apparently triggered, with the largest <span class="hlt">earthquake</span> (Ml 3.5) occurring during the large-amplitude Love surface waves. The Chile mainshock also triggered numerous tremor bursts near the Parkfield-Cholame section of the San Andreas Fault (SAF). The locally triggered tremor bursts are partially masked at lower frequencies by the regionally triggered <span class="hlt">earthquake</span> signals from Coso, but can be identified by applying high-pass or matched filters. Both triggered tremor along the SAF and the Ml 3.5 <span class="hlt">earthquake</span> in Coso are consistent with frictional failure at different depths on critically-stressed faults under the Coulomb failure criteria. The triggered tremor, however, appears to be more phase-correlated with the surface waves than the triggered <span class="hlt">earthquakes</span>, likely reflecting differences in constitutive properties between the brittle, seismogenic crust and the underlying lower crust.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/misc/tl/0001/tl0001.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/misc/tl/0001/tl0001.pdf"><span>The Parkfield-Cholame, <span class="hlt">California</span>, <span class="hlt">earthquakes</span> of June-August, 1966; instrumental seismic studies</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Eaton, Jerry P.</p> <p>1967-01-01</p> <p>U.S. Geological Survey instrumental seismic studies in the Parkfield-Cholame area consist of three related parts that were undertaken as pilot studies in a program designed to develop improved tools and concepts for investigating the properties and behavior of the San Andreas fault. These studies include: 1. The long=term monitoring of the seismic background on the San Andreas fault in Cholame <span class="hlt">Valley</span> by means of a short-period Benioff seismograph station at Gold Hill. 2. The investigation of the geometry of the zone of aftershocks of the June 27 <span class="hlt">earthquakes</span> by means of a small portable cluster of short-period, primarily vertical-component seismographs. 3. The seismic-refraction calibration of the region enclosing the aftershock source by means of three short reversed refraction profiles and a "calibration shot" near the epicenter of the main June 27 <span class="hlt">earthquake</span>. This brief report outlines the work that has been completed and presents some preliminary results obtained from analysis of records from Gold Hill and the portable cluster.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70021865','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70021865"><span>TriNet "ShakeMaps": Rapid generation of peak ground motion and intensity maps for <span class="hlt">earthquakes</span> in southern <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wald, D.J.; Quitoriano, V.; Heaton, T.H.; Kanamori, H.; Scrivner, C.W.; Worden, C.B.</p> <p>1999-01-01</p> <p>Rapid (3-5 minutes) generation of maps of instrumental ground-motion and shaking intensity is accomplished through advances in real-time seismographic data acquisition combined with newly developed relationships between recorded ground-motion parameters and expected shaking intensity values. Estimation of shaking over the entire regional extent of southern <span class="hlt">California</span> is obtained by the spatial interpolation of the measured ground motions with geologically based frequency and amplitude-dependent site corrections. Production of the maps is automatic, triggered by any significant <span class="hlt">earthquake</span> in southern <span class="hlt">California</span>. Maps are now made available within several minutes of the <span class="hlt">earthquake</span> for public and scientific consumption via the World Wide Web; they will be made available with dedicated communications for emergency response agencies and critical users.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.T53B2137S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.T53B2137S"><span>Damage from the El Mayor-Cucapah <span class="hlt">earthquake</span>, April 2010: Why society cannot afford to ignore seismic risks to agricultural regions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stenner, H. D.; Mathieson, E. L.; Okubo, S.; Anderson, R.; Rodriguez C., M. A.</p> <p>2010-12-01</p> <p>The M7.2 El Mayor-Cucapah <span class="hlt">earthquake</span> of April 4, 2010 in Mexico’s Baja <span class="hlt">California</span> caused extensive damage to the agricultural area of Mexicali <span class="hlt">Valley</span>. The damage included wide-spread liquefaction and lateral spreading which destroyed or damaged irrigation canals. Without water, wheat, alfalfa, and other crops were lost. Fields were cut by fissures and partially buried by massive sand blows. Regional tilting from the <span class="hlt">earthquake</span> was a serious issue for the gravity-controlled irrigation system. Ruptured canals and groundwater from sand blows flooded fields, roads, and towns. Flooding further damaged crops and brought contamination with it. Fissures and scarps through farm communities cracked buildings; ruptured water, sewer, and other pipelines; and made roads temporarily difficult to pass. Economically, farmers, seasonal farm workers, and agricultural suppliers were affected; reducing their ability to consume the goods and services of businesses unrelated to agriculture. Similar damage was observed in earlier <span class="hlt">earthquakes</span> over the past 100 years. Society quickly forgets how the earth responds to strong shaking. We hope to provide a vivid portrait of this agricultural disaster so that other farming communities prone to strong seismic shaking may visualize what can happen from their own inevitable future <span class="hlt">earthquake</span>. Fissure and sand blows southeast of Cucapah, Baja <span class="hlt">California</span>, April 16, 2010. Heavily damaged irrigation canal northwest of Zacamoto, Baja <span class="hlt">California</span>, April 15, 2010.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28469673','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28469673"><span>Understanding Public Views about Air Quality and Air Pollution Sources in the San Joaquin <span class="hlt">Valley</span>, <span class="hlt">California</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cisneros, Ricardo; Brown, Paul; Cameron, Linda; Gaab, Erin; Gonzalez, Mariaelena; Ramondt, Steven; Veloz, David; Song, Anna; Schweizer, Don</p> <p>2017-01-01</p> <p>The San Joaquin <span class="hlt">Valley</span> of <span class="hlt">California</span> has poor air quality and high rates of asthma. Surveys were collected from 744 residents of the San Joaquin <span class="hlt">Valley</span> from November 2014 to January 2015 to examine the public's views about air quality. The results of this study suggest that participants exposed to high PM 2.5 (particulate matter less than 2.5 microns in size) concentrations perceived air pollution to be of the worst quality. Air quality in the San Joaquin <span class="hlt">Valley</span> was primarily perceived as either moderate or unhealthy for sensitive groups. Females perceived air pollution to be of worse quality compared to males. Participants perceived unemployment, crime, and obesity to be the top three most serious community problems in the San Joaquin <span class="hlt">Valley</span>. Participants viewed cars and trucks, windblown dust, and factories as the principle contributors to air pollution in the area. There is a need to continue studying public perceptions of air quality in the San Joaquin <span class="hlt">Valley</span> with a more robust survey with more participants over several years and seasons.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5392406','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5392406"><span>Understanding Public Views about Air Quality and Air Pollution Sources in the San Joaquin <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Brown, Paul; Cameron, Linda; Gaab, Erin; Gonzalez, Mariaelena; Ramondt, Steven; Veloz, David; Song, Anna; Schweizer, Don</p> <p>2017-01-01</p> <p>The San Joaquin <span class="hlt">Valley</span> of <span class="hlt">California</span> has poor air quality and high rates of asthma. Surveys were collected from 744 residents of the San Joaquin <span class="hlt">Valley</span> from November 2014 to January 2015 to examine the public's views about air quality. The results of this study suggest that participants exposed to high PM2.5 (particulate matter less than 2.5 microns in size) concentrations perceived air pollution to be of the worst quality. Air quality in the San Joaquin <span class="hlt">Valley</span> was primarily perceived as either moderate or unhealthy for sensitive groups. Females perceived air pollution to be of worse quality compared to males. Participants perceived unemployment, crime, and obesity to be the top three most serious community problems in the San Joaquin <span class="hlt">Valley</span>. Participants viewed cars and trucks, windblown dust, and factories as the principle contributors to air pollution in the area. There is a need to continue studying public perceptions of air quality in the San Joaquin <span class="hlt">Valley</span> with a more robust survey with more participants over several years and seasons. PMID:28469673</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/ofr02369/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/ofr02369/"><span>Santa Clara <span class="hlt">Valley</span> water district multi-aquifer monitoring-well site, Coyote Creek Outdoor Classroom, San Jose, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hanson, R.T.; Newhouse, M.W.; Wentworth, C.M.; Williams, C.F.; Noce, T.E.; Bennett, M.J.</p> <p>2002-01-01</p> <p>The U.S. Geological Survey (USGS), in cooperation with the Santa Clara <span class="hlt">Valley</span> Water District (SCVWD), has completed the first of several multiple-aquifer monitoring-well sites in the Santa Clara <span class="hlt">Valley</span>. This site monitors ground-water levels and chemistry in the one of the major historic subsidence regions south of San Jose, <span class="hlt">California</span>, at the Coyote Creek Outdoor Classroom (CCOC) (fig. 1) and provides additional basic information about the geology, hydrology, geochemistry, and subsidence potential of the upper- and lower-aquifer systems that is a major source of public water supply in the Santa Clara <span class="hlt">Valley</span>. The site also serves as a science education exhibit at the outdoor classroom operated by SCVWD.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=redistricting&pg=2&id=EJ475279','ERIC'); return false;" href="https://eric.ed.gov/?q=redistricting&pg=2&id=EJ475279"><span>Asian Americans and Latinos in San Gabriel <span class="hlt">Valley</span>, <span class="hlt">California</span>: Ethnic Political Cooperation and Redistricting 1990-92.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Saito, Leland T.</p> <p>1993-01-01</p> <p>Examines political relationships between Asian Americans and Latinos in the San Gabriel <span class="hlt">Valley</span>, Los Angeles (<span class="hlt">California</span>), focusing on an Asian-American organization dealing with redistricting and reapportioning, and reviews how this group allied with its Latino counterpart. The importance of federal law and legal precedent is demonstrated. (SLD)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2012-01-06/pdf/C1-2011-33660.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2012-01-06/pdf/C1-2011-33660.pdf"><span>77 FR 745 - Revisions to the <span class="hlt">California</span> State Implementation Plan, San Joaquin <span class="hlt">Valley</span> Unified Air Pollution...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2012-01-06</p> <p>... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 52 [EPA-R09-OAR-2011-0547; FRL-9480-1] Revisions to the <span class="hlt">California</span> State Implementation Plan, San Joaquin <span class="hlt">Valley</span> Unified Air Pollution Control District (SJVUAPCD) Correction In rule document 2011-33660 appearing on pages 214-217 in the issue of Wednesday...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.V13C3137C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.V13C3137C"><span>Monitoring the Thermal Regime at Hot Creek and Vicinity, Long <span class="hlt">Valley</span> Caldera, Eastern <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Clor, L. E.; Hurwitz, S.; Howle, J.</p> <p>2015-12-01</p> <p>Hot Creek Gorge contains the most obvious surface expression of the hydrothermal system in Long <span class="hlt">Valley</span> Caldera, <span class="hlt">California</span>, discharging 200-300 L/s of thermal water according to USGS measurements made since 1988. Formerly, Hot Creek was a popular public swimming area, but it was closed in 2006 due to unpredictable temperature fluctuations and sporadic geysering of thermal water within the creek (Farrar et al. USGS Fact Sheet2007-3045). The USGS has monitored the thermal regime in the area since the mid-1980s, including a long-term series of studies 0.6 km away at well CH-10b. Temperature measurements in the ~100 m deep well, which have been performed on an intermittent basis since it was drilled in 1983, reveal a complex temperature profile. Temperatures increase with depth to a maximum at about 45 meters below the ground surface, and then decrease steadily to the bottom of the well. The depth of the temperature maximum in the well (~45 m) corresponds to an elevation of ~2,120 m, roughly equivalent to the elevation of Hot Creek, and appears to sample the same hydrothermal flow system that supplies thermal features at the surface in the gorge. Starting in the early 1990s, the maximum temperature in CH-10b rose from 93.4°C to its peak in 2007 at 101.0°C. A cooling trend was observed beginning in 2009 and continues to present (99.3°C in June 2015). As the input into CH-10b is at the elevation of the creek, it exhibits the potential for response to thermal events at Hot Creek, and could provide a useful tool for monitoring future hazards. On short timescales, CH-10b also responds to large global <span class="hlt">earthquakes</span>, greater than ~M7. These responses are captured with continuously logged high-frequency data (5s), and are usually characterized by a co-seismic water level drop of up to ten centimeters. Water levels tend to recover to pre-<span class="hlt">earthquake</span> levels within a few hours to days.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70036411','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70036411"><span>Winter habitat associations of diurnal raptors in <span class="hlt">Californias</span> Central <span class="hlt">Valley</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Pandolrno, E.R.; Herzog, M.P.; Hooper, S.L.; Smith, Z.</p> <p>2011-01-01</p> <p>The wintering raptors of <span class="hlt">California</span>'s Central <span class="hlt">Valley</span> are abundant and diverse. Despite this, little information exists on the habitats used by these birds in winter. We recorded diurnal raptors along 19 roadside survey routes throughout the Central <span class="hlt">Valley</span> for three consecutive winters between 2007 and 2010. We obtained data sufficient to determine significant positive and negative habitat associations for the White-tailed Kite (Elanus leucurus), Bald Eagle {Haliaeetus leucocephalus), Northern Harrier (Circus cyaneus), Red-tailed Hawk (Buteo jamaicensis), Ferruginous Hawk (Buteo regalis), Rough-legged Hawk (Buteo lagopus), American Kestrel (Falco sparverius), and Prairie Falcon (Falco mexicanus). The Prairie Falcon and Ferruginous and Rough-legged hawks showed expected strong positive associations with grasslands. The Bald Eagle and Northern Harrier were positively associated not only with wetlands but also with rice. The strongest positive association for the White-tailed Kite was with wetlands. The Red-tailed Hawk was positively associated with a variety of habitat types but most strongly with wetlands and rice. The American Kestrel, Northern Harrier, and White-tailed Kite were positively associated with alfalfa. Nearly all species were negatively associated with urbanized landscapes, orchards, and other intensive forms of agriculture. The White-tailed Kite, Northern Harrier, Redtailed Hawk, Ferruginous Hawk, and American Kestrel showed significant negative associations with oak savanna. Given the rapid conversion of the Central <span class="hlt">Valley</span> to urban and intensive agricultural uses over the past few decades, these results have important implications for conservation of these wintering raptors in this region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20120015869&hterms=Time+series&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DTime%2Bseries','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20120015869&hterms=Time+series&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DTime%2Bseries"><span>GPS Time Series Analysis of Southern <span class="hlt">California</span> Associated with the 2010 M7.2 El Mayor/Cucapah <span class="hlt">Earthquake</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Granat, Robert; Donnellan, Andrea</p> <p>2011-01-01</p> <p>The Magnitude 7.2 El-Mayor/Cucapah <span class="hlt">earthquake</span> the occurred in Mexico on April 4, 2012 was well instrumented with continuous GPS stations in <span class="hlt">California</span>. Large Offsets were observed at the GPS stations as a result of deformation from the <span class="hlt">earthquake</span> providing information about the co-seismic fault slip as well as fault slip from large aftershocks. Information can also be obtained from the position time series at each station.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2008/1222/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2008/1222/"><span>Potential Effects of a Scenario <span class="hlt">Earthquake</span> on the Economy of Southern <span class="hlt">California</span>: Small Business Exposure and Sensitivity Analysis to a Magnitude 7.8 <span class="hlt">Earthquake</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sherrouse, Benson C.; Hester, David J.; Wein, Anne M.</p> <p>2008-01-01</p> <p>The Multi-Hazards Demonstration Project (MHDP) is a collaboration between the U.S. Geological Survey (USGS) and various partners from the public and private sectors and academia, meant to improve Southern <span class="hlt">California</span>'s resiliency to natural hazards (Jones and others, 2007). In support of the MHDP objectives, the ShakeOut Scenario was developed. It describes a magnitude 7.8 (M7.8) <span class="hlt">earthquake</span> along the southernmost 300 kilometers (200 miles) of the San Andreas Fault, identified by geoscientists as a plausible event that will cause moderate to strong shaking over much of the eight-county (Imperial, Kern, Los Angeles, Orange, Riverside, San Bernardino, San Diego, and Ventura) Southern <span class="hlt">California</span> region. This report contains an exposure and sensitivity analysis of small businesses in terms of labor and employment statistics. Exposure is measured as the absolute counts of labor market variables anticipated to experience each level of Instrumental Intensity (a proxy measure of damage). Sensitivity is the percentage of the exposure of each business establishment size category to each Instrumental Intensity level. The analysis concerns the direct effect of the <span class="hlt">earthquake</span> on small businesses. The analysis is inspired by the Bureau of Labor Statistics (BLS) report that analyzed the labor market losses (exposure) of a M6.9 <span class="hlt">earthquake</span> on the Hayward fault by overlaying geocoded labor market data on Instrumental Intensity values. The method used here is influenced by the ZIP-code-level data provided by the <span class="hlt">California</span> Employment Development Department (CA EDD), which requires the assignment of Instrumental Intensities to ZIP codes. The ZIP-code-level labor market data includes the number of business establishments, employees, and quarterly payroll categorized by business establishment size.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70191708','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70191708"><span>Connecting crustal seismicity and <span class="hlt">earthquake</span>-driven stress evolution in Southern <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Pollitz, Fred; Cattania, Camilla</p> <p>2017-01-01</p> <p>Tectonic stress in the crust evolves during a seismic cycle, with slow stress accumulation over interseismic periods, episodic stress steps at the time of <span class="hlt">earthquakes</span>, and transient stress readjustment during a postseismic period that may last months to years. Static stress transfer to surrounding faults has been well documented to alter regional seismicity rates over both short and long time scales. While static stress transfer is instantaneous and long lived, postseismic stress transfer driven by viscoelastic relaxation of the ductile lower crust and mantle leads to additional, slowly varying stress perturbations. Both processes may be tested by comparing a decade-long record of regional seismicity to predicted time-dependent seismicity rates based on a stress evolution model that includes viscoelastic stress transfer. Here we explore crustal stress evolution arising from the seismic cycle in Southern <span class="hlt">California</span> from 1981 to 2014 using five M≥6.5 source quakes: the M7.3 1992 Landers, M6.5 1992 Big Bear, M6.7 1994 Big Bear, M7.1 1999 Hector Mine, and M7.2 2010 El Mayor-Cucapah <span class="hlt">earthquakes</span>. We relate the stress readjustment in the surrounding crust generated by each quake to regional seismicity using rate-and-state friction theory. Using a log likelihood approach, we quantify the potential to trigger seismicity of both static and viscoelastic stress transfer, finding that both processes have systematically shaped the spatial pattern of Southern <span class="hlt">California</span> seismicity since 1992.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.S51A2326N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.S51A2326N"><span>Web Services and Data Enhancements at the Northern <span class="hlt">California</span> <span class="hlt">Earthquake</span> Data Center</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Neuhauser, D. S.; Zuzlewski, S.; Lombard, P. N.; Allen, R. M.</p> <p>2013-12-01</p> <p>The Northern <span class="hlt">California</span> <span class="hlt">Earthquake</span> Data Center (NCEDC) provides data archive and distribution services for seismological and geophysical data sets that encompass northern <span class="hlt">California</span>. The NCEDC is enhancing its ability to deliver rapid information through Web Services. NCEDC Web Services use well-established web server and client protocols and REST software architecture to allow users to easily make queries using web browsers or simple program interfaces and to receive the requested data in real-time rather than through batch or email-based requests. Data are returned to the user in the appropriate format such as XML, RESP, simple text, or MiniSEED depending on the service and selected output format. The NCEDC offers the following web services that are compliant with the International Federation of Digital Seismograph Networks (FDSN) web services specifications: (1) fdsn-dataselect: time series data delivered in MiniSEED format, (2) fdsn-station: station and channel metadata and time series availability delivered in StationXML format, (3) fdsn-event: <span class="hlt">earthquake</span> event information delivered in QuakeML format. In addition, the NCEDC offers the the following IRIS-compatible web services: (1) sacpz: provide channel gains, poles, and zeros in SAC format, (2) resp: provide channel response information in RESP format, (3) dataless: provide station and channel metadata in Dataless SEED format. The NCEDC is also developing a web service to deliver timeseries from pre-assembled event waveform gathers. The NCEDC has waveform gathers for ~750,000 northern and central <span class="hlt">California</span> events from 1984 to the present, many of which were created by the USGS NCSN prior to the establishment of the joint NCSS (Northern <span class="hlt">California</span> Seismic System). We are currently adding waveforms to these older event gathers with time series from the UCB networks and other networks with waveforms archived at the NCEDC, and ensuring that the waveform for each channel in the event gathers have the highest</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title27-vol1/pdf/CFR-2011-title27-vol1-sec9-191.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title27-vol1/pdf/CFR-2011-title27-vol1-sec9-191.pdf"><span>27 CFR 9.191 - Ramona <span class="hlt">Valley</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-04-01</p> <p>... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Ramona <span class="hlt">Valley</span>. 9.191 Section 9.191 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT...) Borrego <span class="hlt">Valley</span>, <span class="hlt">California</span>, 1982 edition; and (2) El Cajon, <span class="hlt">California</span>, 1979 edition. (c) Boundary. The...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title27-vol1/pdf/CFR-2010-title27-vol1-sec9-191.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title27-vol1/pdf/CFR-2010-title27-vol1-sec9-191.pdf"><span>27 CFR 9.191 - Ramona <span class="hlt">Valley</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-04-01</p> <p>... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Ramona <span class="hlt">Valley</span>. 9.191 Section 9.191 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT...) Borrego <span class="hlt">Valley</span>, <span class="hlt">California</span>, 1982 edition; and (2) El Cajon, <span class="hlt">California</span>, 1979 edition. (c) Boundary. The...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/50012','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/50012"><span>Phenotypic variation in <span class="hlt">California</span> populations of <span class="hlt">valley</span> oak (Quercus lobata Née) sampled along elevational gradients</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Ana L. Albarrán-Lara; Jessica W. Wright; Paul F. Gugger; Annette Delfino-Mix; Juan Manuel Peñaloza-Ramírez; Victoria L. Sork</p> <p>2015-01-01</p> <p><span class="hlt">California</span> oaks exhibit tremendous phenotypic variation throughout their range. This variation reflects phenotypic plasticity in tree response to local environmental conditions as well as genetic differences underlying those phenotypes. In this study, we analyze phenotypic variation in leaf traits for <span class="hlt">valley</span> oak adults sampled along three elevational transects and in...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JGRD..117.0V25P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JGRD..117.0V25P"><span>Airborne observations of methane emissions from rice cultivation in the Sacramento <span class="hlt">Valley</span> of <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peischl, J.; Ryerson, T. B.; Holloway, J. S.; Trainer, M.; Andrews, A. E.; Atlas, E. L.; Blake, D. R.; Daube, B. C.; Dlugokencky, E. J.; Fischer, M. L.; Goldstein, A. H.; Guha, A.; Karl, T.; Kofler, J.; Kosciuch, E.; Misztal, P. K.; Perring, A. E.; Pollack, I. B.; Santoni, G. W.; Schwarz, J. P.; Spackman, J. R.; Wofsy, S. C.; Parrish, D. D.</p> <p>2012-12-01</p> <p>Airborne measurements of methane (CH4) and carbon dioxide (CO2) were taken over the rice growing region of <span class="hlt">California</span>'s Sacramento <span class="hlt">Valley</span> in the late spring of 2010 and 2011. From these and ancillary measurements, we show that CH4 mixing ratios were higher in the planetary boundary layer above the Sacramento <span class="hlt">Valley</span> during the rice growing season than they were before it, which we attribute to emissions from rice paddies. We derive daytime emission fluxes of CH4 between 0.6 and 2.0% of the CO2 taken up by photosynthesis on a per carbon, or mole to mole, basis. We also use a mixing model to determine an average CH4/CO2 flux ratio of -0.6% for one day early in the growing season of 2010. We conclude the CH4/CO2 flux ratio estimates from a single rice field in a previous study are representative of rice fields in the Sacramento <span class="hlt">Valley</span>. If generally true, the <span class="hlt">California</span> Air Resources Board (CARB) greenhouse gas inventory emission rate of 2.7 × 1010 g CH4/yr is approximately three times lower than the range of probable CH4 emissions (7.8-9.3 × 1010 g CH4/yr) from rice cultivation derived in this study. We attribute this difference to decreased burning of the residual rice crop since 1991, which leads to an increase in CH4 emissions from rice paddies in succeeding years, but which is not accounted for in the CARB inventory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA12091.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA12091.html"><span>Death <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2009-06-29</p> <p>Death <span class="hlt">Valley</span>, Calif., has the lowest point in North America, Badwater at 85.5 meters 282 feet below sea level. It is also the driest and hottest location in North America. This image is from NASA Terra spacecraft.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.A21C0257Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.A21C0257Y"><span>Comparison of Oxygenate Mixing Ratios Observed in the San Joaquin <span class="hlt">Valley</span>, <span class="hlt">California</span>, as a Consequence of Dairy Farming</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, M. M.; Blake, D. R.</p> <p>2009-12-01</p> <p>The San Joaquin <span class="hlt">Valley</span> Air Basin in Central <span class="hlt">California</span> is plagued with air quality problems, and is classified by the U.S. Environmental Protection Agency (EPA) as a serious non-attainment area for health-based eight-hour federal ozone (smog) standard (1). One of the main sources of Volatile Organic Compounds (VOCs), and indirect sources of ozone in the <span class="hlt">Valley</span>, has been identified as dairy farming (2). Among these compounds, we have found that several OVOCs such as ethanol, methanol, acetone and acetaldehyde are produced in major quantities throughout the San Joaquin <span class="hlt">valley</span> as by-products of yeast fermentation of silage and photochemical oxidation. These oxygenates, especially ethanol, play an important role in ozone (O3) formation within the <span class="hlt">valley</span>. Since 2008, several different types of sampling protocols have been employed by our group in order to determine the degree of enhancement of the four oxygenates in the <span class="hlt">valley</span> air shed, as well as to determine their sources, emission profiles and emission rates (2). In 2008 and 2009, samples were in early summer, allowing us to compare the difference in concentration levels between both years.The photochemical production of ozone was calculated for each of the four oxygenates and approximately one hundred other quantified VOCs. Based on the Maximum Incremental Reactivity (MIR) scale and concentrations of each oxygenate in the atmosphere, for both 2008 and 2009, as much as 15% of O3 production in the <span class="hlt">valley</span> is from ethanol and its photochemical by-product acetaldehyde. Our findings suggest that the data observed in 2008 is consistent with that observed in 2009, with a slight decrease in concentrations overall for 2009. 1. Lindberg, J. Analysis of the San Joaquin <span class="hlt">Valley</span> 2007 Ozone Plan. State of <span class="hlt">California</span> Air Resources Board. Final Draft Staff Report. 5/30/2007. 2. M. Yang, S. Meinardi, C. Krauter, D.R. Blake. Characterization of VOC Emissions from Various Components of Dairy Farming and their effect on San Joaquin</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70189617','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70189617"><span>Unusual downhole and surface free-field records near the Carquinez Strait bridges during the 24 August 2014 Mw6.0 South Napa, <span class="hlt">California</span> <span class="hlt">earthquake</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Çelebi, Mehmet; Ghahari, S. Farid; Taciroglu, Ertugrul</p> <p>2015-01-01</p> <p>This paper reports the results of Part A of a study of the recorded strong-motion accelerations at the well-instrumented network of the two side-by-side parallel bridges over the Carquinez Strait during the 24 August 2014 (Mw6.0 ) South Napa, Calif. <span class="hlt">earthquake</span> that occurred at 03:20:44 PDT with epicentral coordinates 38.22N, 122.31W. (http://<span class="hlt">earthquake.usgs.gov/earthquakes</span>/eqarchives/poster/2014/20140824.php, last accessed on October 17, 2014). Both bridges and two boreholes were instrumented by the <span class="hlt">California</span> Strong motion Instrumentation Program (CSMIP) of <span class="hlt">California</span> Geological Survey (CGS) (Shakal et al., 2014). A comprehensive comparison of several ground motion prediction equations as they relate to recorded ground motions of the <span class="hlt">earthquake</span> is provided by Baltay and Boatright (2015).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMNG13A1860S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMNG13A1860S"><span>The Virtual Quake <span class="hlt">Earthquake</span> Simulator: <span class="hlt">Earthquake</span> Probability Statistics for the El Mayor-Cucapah Region and Evidence of Predictability in Simulated <span class="hlt">Earthquake</span> Sequences</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schultz, K.; Yoder, M. R.; Heien, E. M.; Rundle, J. B.; Turcotte, D. L.; Parker, J. W.; Donnellan, A.</p> <p>2015-12-01</p> <p>We introduce a framework for developing <span class="hlt">earthquake</span> forecasts using Virtual Quake (VQ), the generalized successor to the perhaps better known Virtual <span class="hlt">California</span> (VC) <span class="hlt">earthquake</span> simulator. We discuss the basic merits and mechanics of the simulator, and we present several statistics of interest for <span class="hlt">earthquake</span> forecasting. We also show that, though the system as a whole (in aggregate) behaves quite randomly, (simulated) <span class="hlt">earthquake</span> sequences limited to specific fault sections exhibit measurable predictability in the form of increasing seismicity precursory to large m > 7 <span class="hlt">earthquakes</span>. In order to quantify this, we develop an alert based forecasting metric similar to those presented in Keilis-Borok (2002); Molchan (1997), and show that it exhibits significant information gain compared to random forecasts. We also discuss the long standing question of activation vs quiescent type <span class="hlt">earthquake</span> triggering. We show that VQ exhibits both behaviors separately for independent fault sections; some fault sections exhibit activation type triggering, while others are better characterized by quiescent type triggering. We discuss these aspects of VQ specifically with respect to faults in the Salton Basin and near the El Mayor-Cucapah region in southern <span class="hlt">California</span> USA and northern Baja <span class="hlt">California</span> Norte, Mexico.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70011954','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70011954"><span>Reservoir properties of submarine- fan facies: Great <span class="hlt">Valley</span> sequence, <span class="hlt">California</span>.</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>McLean, H.</p> <p>1981-01-01</p> <p>Submarine-fan sandstones of the Great <span class="hlt">Valley</span> sequence west of the Sacramento <span class="hlt">Valley</span>, <span class="hlt">California</span>, have low porosities and permeabilities. However, petrography and scanning electron microscope studies indicate that most sands in almost all submarine-fan environments are originally porous and permeable. Thin turbidite sandstones deposited in areas dominated by shale in the outer-fan and basin-plain are cemented mainly by calcite; shale dewatering is inferred to contribute to rapid cementation early in the burial process. Sands deposited in inner- and middle-fan channels with only thin shale beds have small percentrages of intergranular cement. The original porosity is reduced mechanically at shallow depths and by pressure solution at deeperlevels. Permeability decreases with increasing age of the rocks, as a result of increasing burial depths. Computer-run stepwise regression analyses show that the porosity is inversely related to the percentage of calcite cement. The results reported here indicate original porosity and permeability can be high in deep-water submarine fans and that fan environments dominated by sand (with high sand/shale ratios) are more likely to retain higher porosity and permeability to greater depths than sand interbedded with thick shale sequences.-from Author</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014GeoRL..41.3251B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GeoRL..41.3251B"><span>Winter fog is decreasing in the fruit growing region of the Central <span class="hlt">Valley</span> of <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baldocchi, Dennis; Waller, Eric</p> <p>2014-05-01</p> <p>The Central <span class="hlt">Valley</span> of <span class="hlt">California</span> is home to a variety of fruit and nut trees. These trees account for 95% of the U.S. production, but they need a sufficient amount of winter chill to achieve rest and quiescence for the next season's buds and flowers. In prior work, we reported that the accumulation of winter chill is declining in the Central <span class="hlt">Valley</span>. We hypothesize that a reduction in winter fog is cooccurring and is contributing to the reduction in winter chill. We examined a 33 year record of satellite remote sensing to develop a fog climatology for the Central <span class="hlt">Valley</span>. We find that the number of winter fog events, integrated spatially, decreased 46%, on average, over 32 winters, with much year to year variability. Less fog means warmer air and an increase in the energy balance on buds, which amplifies their warming, reducing their chill accumulation more.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ1164751.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ1164751.pdf"><span>Introducing Teachers to Geospatial Technology While Helping Them to Discover Vegetation Patterns in Owens <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Sherman-Morris, Kathleen; Morris, John; Thompson, Keith</p> <p>2009-01-01</p> <p>A field course attended by science teachers in <span class="hlt">California</span>'s Owens <span class="hlt">Valley</span> incorporated geospatial technology to reinforce the relationship between elevation, aspect, or the direction a mountain slope faces, and vegetation. Teachers were provided GPS units to record locations and plant communities throughout the 9-day field course. At the end of the…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70027809','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70027809"><span>Magmatic unrest beneath Mammoth Mountain, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hill, D.P.; Prejean, S.</p> <p>2005-01-01</p> <p>Mammoth Mountain, which stands on the southwest rim of Long <span class="hlt">Valley</span> caldera in eastern <span class="hlt">California</span>, last erupted ???57,000 years BP. Episodic volcanic unrest detected beneath the mountain since late 1979, however, emphasizes that the underlying volcanic system is still active and capable of producing future volcanic eruptions. The unrest symptoms include swarms of small (M ??? 3) <span class="hlt">earthquakes</span>, spasmodic bursts (rapid-fire sequences of brittle-failure <span class="hlt">earthquakes</span> with overlapping coda), long-period (LP) and very-long-period (VLP) volcanic <span class="hlt">earthquakes</span>, ground deformation, diffuse emission of magmatic CO2, and fumarole gases with elevated 3He/4He ratios. Spatial-temporal relations defined by the multi-parameter monitoring data together with <span class="hlt">earthquake</span> source mechanisms suggest that this Mammoth Mountain unrest is driven by the episodic release of a volume of CO2-rich hydrous magmatic fluid derived from the upper reaches of a plexus of basaltic dikes and sills at mid-crustal depths (10-20 km). As the mobilized fluid ascends through the brittle-plastic transition zone and into overlying brittle crust, it triggers <span class="hlt">earthquake</span> swarm activity and, in the case of the prolonged, 11-month-long <span class="hlt">earthquake</span> swarm of 1989, crustal deformation and the onset of diffuse CO2 emissions. Future volcanic activity from this system would most likely involve steam explosions or small-volume, basaltic, strombolian or Hawaiaan style eruptions. The impact of such an event would depend critically on vent location and season.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/pp/pp1550/pp1550f/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/pp/pp1550/pp1550f/"><span>Chapter F. The Loma Prieta, <span class="hlt">California</span>, <span class="hlt">Earthquake</span> of October 17, 1989 - Tectonic Processes and Models</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Simpson, Robert W.</p> <p>1994-01-01</p> <p>If there is a single theme that unifies the diverse papers in this chapter, it is the attempt to understand the role of the Loma Prieta <span class="hlt">earthquake</span> in the context of the <span class="hlt">earthquake</span> 'machine' in northern <span class="hlt">California</span>: as the latest event in a long history of shocks in the San Francisco Bay region, as an incremental contributor to the regional deformation pattern, and as a possible harbinger of future large <span class="hlt">earthquakes</span>. One of the surprises generated by the <span class="hlt">earthquake</span> was the rather large amount of uplift that occurred as a result of the reverse component of slip on the southwest-dipping fault plane. Preearthquake conventional wisdom had been that large <span class="hlt">earthquakes</span> in the region would probably be caused by horizontal, right-lateral, strike-slip motion on vertical fault planes. In retrospect, the high topography of the Santa Cruz Mountains and the elevated marine terraces along the coast should have provided some clues. With the observed ocean retreat and the obvious uplift of the coast near Santa Cruz that accompanied the <span class="hlt">earthquake</span>, Mother Nature was finally caught in the act. Several investigators quickly saw the connection between the <span class="hlt">earthquake</span> uplift and the long-term evolution of the Santa Cruz Mountains and realized that important insights were to be gained by attempting to quantify the process of crustal deformation in terms of Loma Prieta-type increments of northward transport and fault-normal shortening.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2012/1011/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2012/1011/"><span>Logs and data from trenches across and near the Green <span class="hlt">Valley</span> Fault at the Mason Road site, Fairfield, Solano County, <span class="hlt">California</span>, 2006-2009</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lienkaemper, James J.; Sickler, Robert R.; Mahan, Shannon; Brown, Johnathan; Reidy, Liam M.; Kimball, Mindy A.</p> <p>2012-01-01</p> <p>The primary purpose of this report is to provide drafted field logs of exploratory trenches excavated across the Green <span class="hlt">Valley</span> Fault in 2007 and 2009 that show evidence for four surface rupturing <span class="hlt">earthquakes</span> in the past one thousand years. The site location and site detail are shown on sheet 1. The trench logs are shown on sheets 1, 2, and 3. We also provide radiocarbon laboratory dates used for chronological modeling of the <span class="hlt">earthquake</span> history. Sheets 4 and 5 show additional data obtained in 2006–2009 to document data obtained in our studies of the long-term geologic slip rate on the Green <span class="hlt">Valley</span> Fault. However, that effort ultimately did not prove feasible and no slip rate estimate resulted.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70168760','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70168760"><span><span class="hlt">Earthquakes</span>, May-June 1991</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Person, W.J.</p> <p>1992-01-01</p> <p>In the United States, a magnitude 5.8 <span class="hlt">earthquake</span> in southern <span class="hlt">California</span> on June 28 killed two people and caused considerable damage. Strong <span class="hlt">earthquakes</span> hit Alaska on May 1 and May 30; the May 1 <span class="hlt">earthquake</span> caused some minor damage. </p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70023577','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70023577"><span>Observations of basin ground motions from a dense seismic array in San Jose, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Frankel, A.; Carver, D.; Cranswick, E.; Bice, T.; Sell, R.; Hanson, S.</p> <p>2001-01-01</p> <p>We installed a dense array of 41 digital seismographs in San Jose, <span class="hlt">California</span>, to evaluate in detail the effects of a deep sedimentary basin and shallow sedimentary deposits on <span class="hlt">earthquake</span> ground motions. This urban array is located near the eastern edge of the Santa Clara <span class="hlt">Valley</span> and spans the Evergreen sedimentary basin identified by gravity data. Average station spacing is 1 km, with three stations initially spaced 110 m apart. Despite the high-noise urban environment, the stations of the array successfully triggered on and recorded small local <span class="hlt">earthquakes</span> (M 2.5-2.8 at 10-25 km distance) and larger regional events such as the M 5.0 Bolinas <span class="hlt">earthquake</span> (90 km distance), M 4.6-5.6 <span class="hlt">earthquakes</span> near Mammoth Lakes (270 km distance), M 4.9-5.6 events in western Nevada (420 km distance) and the M 7.1 Hector Mine <span class="hlt">earthquake</span> (590 km distance). Maps of spectral ratios across the array show that the highest amplitudes in all frequency bands studied (0.125-8 Hz) are generally observed at stations farther from the eastern edge of the Santa Clara <span class="hlt">Valley</span>. Larger spectral amplitudes are often observed above the western edge of the Evergreen Basin. Snapshots of the recorded wavefield crossing the array for regional events to the east reveal that large, low-frequency (0.125-0.5 Hz) arrivals after the S-wave travel from south to north across the array. A moving-window, cross-correlation analysis finds that these later arrivals are surface waves traveling from the south. The timing and propagation direction of these arrivals indicates that they were likely produced by scattering of incident S waves at the border of the Santa Clara <span class="hlt">Valley</span> to the south of the array. It is remarkable that the largest low-frequency phases at many of the <span class="hlt">valley</span> sites for regional events to the east are basin surface waves coming from a direction about 70 degrees different from that of the epicenters. Basin surface waves emanating from the eastern edge of the <span class="hlt">valley</span> are also identified by the cross</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2013/5127/pdf/sir2013-5127.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2013/5127/pdf/sir2013-5127.pdf"><span>Construction of 3-D geologic framework and textural models for Cuyama <span class="hlt">Valley</span> groundwater basin, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sweetkind, Donald S.; Faunt, Claudia C.; Hanson, Randall T.</p> <p>2013-01-01</p> <p>Groundwater is the sole source of water supply in Cuyama <span class="hlt">Valley</span>, a rural agricultural area in Santa Barbara County, <span class="hlt">California</span>, in the southeasternmost part of the Coast Ranges of <span class="hlt">California</span>. Continued groundwater withdrawals and associated water-resource management concerns have prompted an evaluation of the hydrogeology and water availability for the Cuyama <span class="hlt">Valley</span> groundwater basin by the U.S. Geological Survey, in cooperation with the Water Agency Division of the Santa Barbara County Department of Public Works. As a part of the overall groundwater evaluation, this report documents the construction of a digital three-dimensional geologic framework model of the groundwater basin suitable for use within a numerical hydrologic-flow model. The report also includes an analysis of the spatial variability of lithology and grain size, which forms the geologic basis for estimating aquifer hydraulic properties. The geologic framework was constructed as a digital representation of the interpreted geometry and thickness of the principal stratigraphic units within the Cuyama <span class="hlt">Valley</span> groundwater basin, which include younger alluvium, older alluvium, and the Morales Formation, and underlying consolidated bedrock. The framework model was constructed by creating gridded surfaces representing the altitude of the top of each stratigraphic unit from various input data, including lithologic and electric logs from oil and gas wells and water wells, cross sections, and geologic maps. Sediment grain-size data were analyzed in both two and three dimensions to help define textural variations in the Cuyama <span class="hlt">Valley</span> groundwater basin and identify areas with similar geologic materials that potentially have fairly uniform hydraulic properties. Sediment grain size was used to construct three-dimensional textural models that employed simple interpolation between drill holes and two-dimensional textural models for each stratigraphic unit that incorporated spatial structure of the textural data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70176199','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70176199"><span>Characterizing potentially induced <span class="hlt">earthquake</span> rate changes in the Brawley Seismic Zone, southern <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Llenos, Andrea L.; Michael, Andrew J.</p> <p>2016-01-01</p> <p>The Brawley seismic zone (BSZ), in the Salton trough of southern <span class="hlt">California</span>, has a history of <span class="hlt">earthquake</span> swarms and geothermal energy exploitation. Some <span class="hlt">earthquake</span> rate changes may have been induced by fluid extraction and injection activity at local geothermal fields, particularly at the North Brawley Geothermal Field (NBGF) and at the Salton Sea Geothermal Field (SSGF). We explore this issue by examining <span class="hlt">earthquake</span> rate changes and interevent distance distributions in these fields. In Oklahoma and Arkansas, where considerable wastewater injection occurs, increases in background seismicity rate and aftershock productivity and decreases in interevent distance were indicative of fluid‐injection‐induced seismicity. Here, we test if similar changes occur that may be associated with fluid injection and extraction in geothermal areas. We use stochastic epidemic‐type aftershock sequence models to detect changes in the underlying seismogenic processes, shown by statistically significant changes in the model parameters. The most robust model changes in the SSGF roughly occur when large changes in net fluid production occur, but a similar correlation is not seen in the NBGF. Also, although both background seismicity rate and aftershock productivity increased for fluid‐injection‐induced <span class="hlt">earthquake</span> rate changes in Oklahoma and Arkansas, the background rate increases significantly in the BSZ only, roughly corresponding with net fluid production rate increases. Moreover, in both fields the interevent spacing does not change significantly during active energy projects. This suggests that, although geothermal field activities in a tectonically active region may not significantly change the physics of <span class="hlt">earthquake</span> interactions, <span class="hlt">earthquake</span> rates may still be driven by fluid injection or extraction rates, particularly in the SSGF.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70169183','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70169183"><span><span class="hlt">Earthquakes</span>; July-August, 1978</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Person, W.J.</p> <p>1979-01-01</p> <p><span class="hlt">Earthquake</span> activity during this period was about normal. Deaths from <span class="hlt">earthquakes</span> were reported from Greece and Guatemala. Three major <span class="hlt">earthquakes</span> (magnitude 7.0-7.9) occurred in Taiwan, Chile, and Costa Rica. In the United States, the most significant <span class="hlt">earthquake</span> was a magnitude 5.6 on August 13 in southern <span class="hlt">California</span>. </p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013Fract..2150001S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013Fract..2150001S"><span>Multifractal Fluctuations of Jiuzhaigou Tourists Before and after Wenchuan <span class="hlt">Earthquake</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shi, Kai; Li, Wen-Yong; Liu, Chun-Qiong; Huang, Zheng-Wen</p> <p>2013-03-01</p> <p>In this work, multifractal methods have been successfully used to characterize the temporal fluctuations of daily Jiuzhai <span class="hlt">Valley</span> domestic and foreign tourists before and after Wenchuan <span class="hlt">earthquake</span> in China. We used multifractal detrending moving average method (MF-DMA). It showed that Jiuzhai <span class="hlt">Valley</span> tourism markets are characterized by long-term memory and multifractal nature in. Moreover, the major sources of multifractality are studied. Based on the concept of sliding window, the time evolutions of the multifractal behavior of domestic and foreign tourists were analyzed and the influence of Wenchuan <span class="hlt">earthquake</span> on Jiuzhai <span class="hlt">Valley</span> tourism system dynamics were evaluated quantitatively. The study indicates that the inherent dynamical mechanism of Jiuzhai <span class="hlt">Valley</span> tourism system has not been fundamentally changed from long views, although Jiuzhai <span class="hlt">Valley</span> tourism system was seriously affected by the Wenchuan <span class="hlt">earthquake</span>. Jiuzhai <span class="hlt">Valley</span> tourism system has the ability to restore to its previous state in the short term.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.water.usgs.gov/ofr2004-1214/','USGSPUBS'); return false;" href="http://pubs.water.usgs.gov/ofr2004-1214/"><span>Dissolved Pesticide and Organic Carbon Concentrations Detected in Surface Waters, Northern Central <span class="hlt">Valley</span>, <span class="hlt">California</span>, 2001-2002</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Orlando, James L.; Jacobson, Lisa A.; Kuivila, Kathryn</p> <p>2004-01-01</p> <p>Field and laboratory studies were conducted to determine the effects of pesticide mixtures on Chinook salmon under various environmental conditions in surface waters of the northern Central <span class="hlt">Valley</span> of <span class="hlt">California</span>. This project was a collaborative effort between the U.S. Geological Survey (USGS) and the University of <span class="hlt">California</span>. The project focused on understanding the environmental factors that influence the toxicity of pesticides to juvenile salmon and their prey. During the periods January through March 2001 and January through May 2002, water samples were collected at eight surface water sites in the northern Central <span class="hlt">Valley</span> of <span class="hlt">California</span> and analyzed by the USGS for dissolved pesticide and dissolved organic carbon concentrations. Water samples were also collected by the USGS at the same sites for aquatic toxicity testing by the Aquatic Toxicity Laboratory at the University of <span class="hlt">California</span> Davis; however, presentation of the results of these toxicity tests is beyond the scope of this report. Samples were collected to characterize dissolved pesticide and dissolved organic carbon concentrations, and aquatic toxicity, associated with winter storm runoff concurrent with winter run Chinook salmon out-migration. Sites were selected that represented the primary habitat of juvenile Chinook salmon and included major tributaries within the Sacramento and San Joaquin River Basins and the Sacramento?San Joaquin Delta. Water samples were collected daily for a period of seven days during two winter storm events in each year. Additional samples were collected weekly during January through April or May in both years. Concentrations of 31 currently used pesticides were measured in filtered water samples using solid-phase extraction and gas chromatography-mass spectrometry at the U.S. Geological Survey's organic chemistry laboratory in Sacramento, <span class="hlt">California</span>. Dissolved organic carbon concentrations were analyzed in filtered water samples using a Shimadzu TOC-5000A total organic carbon</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.H44A..05M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.H44A..05M"><span>Nitrate Contamination of Deep Aquifers in the Salinas <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moran, J. E.; Esser, B. K.; Hillegonds, D. J.; Holtz, M.; Roberts, S. K.; Singleton, M. J.; Visser, A.; Kulongoski, J. T.; Belitz, K.</p> <p>2011-12-01</p> <p>The Salinas <span class="hlt">Valley</span>, known as 'the salad bowl of the world', has been an agricultural center for more than 100 years. Irrigated row crops such as lettuce and strawberries dominate both land use and water use. Groundwater is the exclusive supply for both irrigation and drinking water. Some irrigation wells and most public water supply wells in the Salinas <span class="hlt">Valley</span> are constructed to draw water from deep portions of the aquifer system, where contamination by nitrate is less likely than in the shallow portions of the aquifer system. However, a number of wells with top perforations greater than 75 m deep, screened below confining or semi-confining units, have nitrate concentrations greater than the Maximum Contaminant Limit (MCL) of 45 mg/L as NO3-. This study uses nitrate concentrations from several hundred irrigation, drinking water, and monitoring wells (Monterey County Water Resources Agency, 1997), along with tritium-helium groundwater ages acquired at Lawrence Livermore National Laboratory through the State of <span class="hlt">California</span> Groundwater Monitoring and Assessment (GAMA) program (reported in Kulongoski et al., 2007 and in Moran et al., in press), to identify nitrate 'hot spots' in the deep aquifer and to examine possible modes of nitrate transport to the deep aquifer. In addition, observed apparent groundwater ages are compared with the results of transport simulations that use particle tracking and a stochastic-geostatistical framework to incorporate aquifer heterogeneity to determine the distribution of travel times from the water table to each well (Fogg et al., 1999). The combined evidence from nitrate, tritium, tritiogenic 3He, and radiogenic 4He concentrations, reveals complex recharge and flow to the capture zone of the deep drinking water wells. Widespread groundwater pumping for irrigation accelerates vertical groundwater flow such that high nitrate groundwater reaches some deep drinking water wells. Deeper portions of the wells often draw in water that recharged</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2003/0006/pdf/of03-6.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2003/0006/pdf/of03-6.pdf"><span>Principal facts for gravity stations in the Dry <span class="hlt">Valley</span> area, west-central Nevada and east-central <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sanger, Elizabeth A.; Ponce, David A.</p> <p>2003-01-01</p> <p>In June, 2002, the U.S. Geological Survey (USGS) established 143 new gravity stations and 12 new rock samples in the Dry <span class="hlt">Valley</span> area, 30 miles north of Reno, Nevada, on the <span class="hlt">California</span> - Nevada border (see fig. 1). This study reports on gravity, magnetic, and physical property data intended for use in modeling the geometry and depth of Dry <span class="hlt">Valley</span> for groundwater analysis. It is part of a larger study that aims to characterize the hydrologic framework of several basins in Washoe County. Dry <span class="hlt">Valley</span> is located south of the Fort Sage Mountains and south-east of Long <span class="hlt">Valley</span>, on USGS 7.5’ quadrangles Constantia and Seven Lakes (fig. 2). The Cretaceous granitic rocks and Tertiary volcanic rocks that bound the sediment filled basin (fig. 3) may be especially important to future modeling because of their impact on groundwater flow. The granitic and volcanic rocks of Dry <span class="hlt">Valley</span> exhibit densities and magnetic susceptibilities higher than the overlaying sediments, and create a distinguishable pattern of gravity and magnetic anomalies that reflect these properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70189164','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70189164"><span>A spatiotemporal clustering model for the Third Uniform <span class="hlt">California</span> <span class="hlt">Earthquake</span> Rupture Forecast (UCERF3‐ETAS): Toward an operational <span class="hlt">earthquake</span> forecast</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Field, Edward; Milner, Kevin R.; Hardebeck, Jeanne L.; Page, Morgan T.; van der Elst, Nicholas; Jordan, Thomas H.; Michael, Andrew J.; Shaw, Bruce E.; Werner, Maximillan J.</p> <p>2017-01-01</p> <p>We, the ongoing Working Group on <span class="hlt">California</span> <span class="hlt">Earthquake</span> Probabilities, present a spatiotemporal clustering model for the Third Uniform <span class="hlt">California</span> <span class="hlt">Earthquake</span> Rupture Forecast (UCERF3), with the goal being to represent aftershocks, induced seismicity, and otherwise triggered events as a potential basis for operational <span class="hlt">earthquake</span> forecasting (OEF). Specifically, we add an epidemic‐type aftershock sequence (ETAS) component to the previously published time‐independent and long‐term time‐dependent forecasts. This combined model, referred to as UCERF3‐ETAS, collectively represents a relaxation of segmentation assumptions, the inclusion of multifault ruptures, an elastic‐rebound model for fault‐based ruptures, and a state‐of‐the‐art spatiotemporal clustering component. It also represents an attempt to merge fault‐based forecasts with statistical seismology models, such that information on fault proximity, activity rate, and time since last event are considered in OEF. We describe several unanticipated challenges that were encountered, including a need for elastic rebound and characteristic magnitude–frequency distributions (MFDs) on faults, both of which are required to get realistic triggering behavior. UCERF3‐ETAS produces synthetic catalogs of M≥2.5 events, conditioned on any prior M≥2.5 events that are input to the model. We evaluate results with respect to both long‐term (1000 year) simulations as well as for 10‐year time periods following a variety of hypothetical scenario mainshocks. Although the results are very plausible, they are not always consistent with the simple notion that triggering probabilities should be greater if a mainshock is located near a fault. Important factors include whether the MFD near faults includes a significant characteristic <span class="hlt">earthquake</span> component, as well as whether large triggered events can nucleate from within the rupture zone of the mainshock. Because UCERF3‐ETAS has many sources of uncertainty, as</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2010-11-30/pdf/2010-29248.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2010-11-30/pdf/2010-29248.pdf"><span>75 FR 74517 - Approval and Promulgation of Implementation Plans; State of <span class="hlt">California</span>; 2008 San Joaquin <span class="hlt">Valley</span>...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2010-11-30</p> <p>...EPA is proposing to approve in part and disapprove in part state implementation plan (SIP) revisions submitted by <span class="hlt">California</span> to provide for attainment of the 1997 annual and 24-hour fine particulate matter (PM2.5) national ambient air quality standards (NAAQS) in the San Joaquin <span class="hlt">Valley</span> (SJV) nonattainment area. The SIP revisions are the SJV 2008 PM2.5 Plan (revised 2010) and portions of the 2007 State Strategy (revised 2009). Specifically, EPA is proposing to approve the emissions inventories as meeting the requirements of the Clean Air Act and EPA's fine particle implementing rule and to approve commitments to implement specific measures and meet specific aggregate emissions reductions by the San Joaquin <span class="hlt">Valley</span> Air Pollution Control District and the <span class="hlt">California</span> Air Resource Board. In addition, we are proposing to find that volatile organic compounds are a PM2.5 attainment plan precursor in the SJV for which controls should be evaluated. EPA is proposing to disapprove the attainment demonstration. EPA is also proposing to disapprove the reasonably available control measures/reasonably available control technology demonstration, the air quality modeling, the reasonable further progress (RFP) demonstration, the contingency measures, and the attainment and RFP conformity motor vehicle emissions budgets. EPA is also proposing to not grant <span class="hlt">California</span>'s request to extend to April 5, 2015 the deadline for the SJV nonattainment area to attain the 1997 PM2.5 NAAQS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70013681','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70013681"><span>WHITTIER NARROWS, <span class="hlt">CALIFORNIA</span> <span class="hlt">EARTHQUAKE</span> OF OCTOBER 1, 1987-PRELIMINARY ASSESSMENT OF STRONG GROUND MOTION RECORDS.</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Brady, A.G.; Etheredge, E.C.; Porcella, R.L.</p> <p>1988-01-01</p> <p>More than 250 strong-motion accelerograph stations were triggered by the Whittier Narrows, <span class="hlt">California</span> <span class="hlt">earthquake</span> of 1 October 1987. Considering the number of multichannel structural stations in the area of strong shaking, this set of records is one of the more significant in history. Three networks, operated by the U. S. Geological Survey, the <span class="hlt">California</span> Division of Mines and Geology, and the University of Southern <span class="hlt">California</span> produced the majority of the records. The excellent performance of the instruments in these and the smaller arrays is attributable to the quality of the maintenance programs. Readiness for a magnitude 8 event is directly related to these maintenance programs. Prior to computer analysis of the analog film records, a number of important structural resonant modes can be identified, and frequencies and simple mode shapes have been scaled.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70193551','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70193551"><span>Transtensional deformation and structural control of contiguous but independent magmatic systems: Mono-Inyo Craters, Mammoth Mountain, and Long <span class="hlt">Valley</span> Caldera, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Riley, P.; Tikoff, B.; Hildreth, Wes</p> <p>2012-01-01</p> <p>The Long <span class="hlt">Valley</span> region of eastern <span class="hlt">California</span> (United States) is the site of abundant late Tertiary–present magmatism, including three geochemically distinct stages of magmatism since ca. 3 Ma: Mammoth Mountain, the Mono-Inyo volcanic chain, and Long <span class="hlt">Valley</span> Caldera. We propose two tectonic models, one explaining the Mammoth Mountain–Mono-Inyo magmatism and the other explaining the presence of Long <span class="hlt">Valley</span> Caldera. First, the ongoing Mammoth Mountain–Mono-Inyo volcanic chain magmatism is explained by a ridge-transform-ridge system, with the Mono-Inyo volcanic chain acting as one ridge segment and the South Moat fault acting as a transform fault. Implicit in this first model is that this region of eastern <span class="hlt">California</span> is beginning to act as an incipient plate boundary. Second, the older Long <span class="hlt">Valley</span> Caldera system is hypothesized to occur in a region of enhanced extension resulting from regional fault block rotation, specifically involving activation of the sinistral faults of the Mina deflection. The tectonic models are consistent with observed spatial and temporal differences in the geochemistry of the regional magmas, and the westward progression of magmatism since ca. 12 Ma.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/pp/1795/a/pp1795a.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/pp/1795/a/pp1795a.pdf"><span>History of <span class="hlt">earthquakes</span> and tsunamis along the eastern Aleutian-Alaska megathrust, with implications for tsunami hazards in the <span class="hlt">California</span> Continental Borderland</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ryan, Holly F.; von Huene, Roland E.; Wells, Ray E.; Scholl, David W.; Kirby, Stephen; Draut, Amy E.; Dumoulin, Julie A.; Dusel-Bacon, C.</p> <p>2012-01-01</p> <p>During the past several years, devastating tsunamis were generated along subduction zones in Indonesia, Chile, and most recently Japan. Both the Chile and Japan tsunamis traveled across the Pacific Ocean and caused localized damage at several coastal areas in <span class="hlt">California</span>. The question remains as to whether coastal <span class="hlt">California</span>, in particular the <span class="hlt">California</span> Continental Borderland, is vulnerable to more extensive damage from a far-field tsunami sourced along a Pacific subduction zone. Assuming that the coast of <span class="hlt">California</span> is at risk from a far-field tsunami, its coastline is most exposed to a trans-Pacific tsunami generated along the eastern Aleutian-Alaska subduction zone. We present the background geologic constraints that could control a possible giant (Mw ~9) <span class="hlt">earthquake</span> sourced along the eastern Aleutian-Alaska megathrust. Previous great <span class="hlt">earthquakes</span> (Mw ~8) in 1788, 1938, and 1946 ruptured single segments of the eastern Aleutian-Alaska megathrust. However, in order to generate a giant <span class="hlt">earthquake</span>, it is necessary to rupture through multiple segments of the megathrust. Potential barriers to a throughgoing rupture, such as high-relief fracture zones or ridges, are absent on the subducting Pacific Plate between the Fox and Semidi Islands. Possible asperities (areas on the megathrust that are locked and therefore subject to infrequent but large slip) are identified by patches of high moment release observed in the historical <span class="hlt">earthquake</span> record, geodetic studies, and the location of forearc basin gravity lows. Global Positioning System (GPS) data indicate that some areas of the eastern Aleutian-Alaska megathrust, such as that beneath Sanak Island, are weakly coupled. We suggest that although these areas will have reduced slip during a giant <span class="hlt">earthquake</span>, they are not really large enough to form a barrier to rupture. A key aspect in defining an <span class="hlt">earthquake</span> source for tsunami generation is determining the possibility of significant slip on the updip end of the megathrust near</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70182774','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70182774"><span>Responses of a tall building in Los Angeles, <span class="hlt">California</span> as inferred from local and distant <span class="hlt">earthquakes</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Çelebi, Mehmet; Hasan Ulusoy,; Nori Nakata,</p> <p>2016-01-01</p> <p>Increasing inventory of tall buildings in the United States and elsewhere may be subjected to motions generated by near and far seismic sources that cause long-period effects. Multiple sets of records that exhibited such effects were retrieved from tall buildings in Tokyo and Osaka ~ 350 km and 770 km from the epicenter of the 2011 Tohoku <span class="hlt">earthquake</span>. In <span class="hlt">California</span>, very few tall buildings have been instrumented. An instrumented 52-story building in downtown Los Angeles recorded seven local and distant <span class="hlt">earthquakes</span>. Spectral and system identification methods exhibit significant low frequencies of interest (~0.17 Hz, 0.56 Hz and 1.05 Hz). These frequencies compare well with those computed by transfer functions; however, small variations are observed between the significant low frequencies for each of the seven <span class="hlt">earthquakes</span>. The torsional and translational frequencies are very close and are coupled. Beating effect is observed in at least two of the seven <span class="hlt">earthquake</span> data.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/7188866-next-new-madrid-earthquake','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/7188866-next-new-madrid-earthquake"><span>The next new Madrid <span class="hlt">earthquake</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Atkinson, W.</p> <p>1988-01-01</p> <p>Scientists who specialize in the study of Mississippi <span class="hlt">Valley</span> <span class="hlt">earthquakes</span> say that the region is overdue for a powerful tremor that will cause major damage and undoubtedly some casualties. The inevitability of a future quake and the lack of preparation by both individuals and communities provided the impetus for this book. It brings together applicable information from many disciplines: history, geology and seismology, engineering, zoology, politics and community planning, economics, environmental science, sociology, and psychology and mental health to provide a perspective of the myriad impacts of a major <span class="hlt">earthquake</span> on the Mississippi <span class="hlt">Valley</span>. The author addresses such basic questionsmore » as What, actually, are <span class="hlt">earthquakes</span> How do they occur Can they be predicted, perhaps even prevented He also addresses those steps that individuals can take to improve their chances for survival both during and after an <span class="hlt">earthquake</span>.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70168881','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70168881"><span><span class="hlt">Earthquakes</span>, September-October, 1979</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Person, W.J.</p> <p>1980-01-01</p> <p>In the United States, <span class="hlt">California</span> experienced the strongest <span class="hlt">earthquake</span> in that State since 1971. The quake, a M=6.8, occurred on October 15, in Baja <span class="hlt">California</span>, Mexico, near the <span class="hlt">California</span> border and caused injuries and damage. </p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70012500','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70012500"><span>Chemical and isotopic prediction of aquifer temperatures in the geothermal system at Long <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fournier, R.O.; Sorey, M.L.; Mariner, R.H.; Truesdell, A.H.</p> <p>1979-01-01</p> <p>Temperatures of aquifers feeding thermal springs and wells in Long <span class="hlt">Valley</span>, <span class="hlt">California</span>, estimated using silica and Na-K-Ca geothermometers and warm spring mixing models, range from 160/dg to about 220??C. This information was used to construct a diagram showing enthalpy-chloride relations for the various thermal waters in the Long <span class="hlt">Valley</span> region. The enthalpy-chloride information suggests that a 282 ?? 10??C aquifer with water containing about 375 mg chloride per kilogram of water is present somewhere deep in the system. That deep water would be related to ??? 220??C Casa Diablo water by mixing with cold water, and to Hot Creek water by first boiling with steam loss and then mixing with cold water. Oxygen and deuterium isotopic data are consistent with that interpretation. An aquifer at 282??C with 375 mg/kg chloride implies a convective heat flow in Long <span class="hlt">Valley</span> of 6.6 ?? 107 cal/s. ?? 1979.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.S21A2146L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.S21A2146L"><span>The Active Fault Parameters for Time-Dependent <span class="hlt">Earthquake</span> Hazard Assessment in Taiwan</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Y.; Cheng, C.; Lin, P.; Shao, K.; Wu, Y.; Shih, C.</p> <p>2011-12-01</p> <p>Taiwan is located at the boundary between the Philippine Sea Plate and the Eurasian Plate, with a convergence rate of ~ 80 mm/yr in a ~N118E direction. The plate motion is so active that <span class="hlt">earthquake</span> is very frequent. In the Taiwan area, disaster-inducing <span class="hlt">earthquakes</span> often result from active faults. For this reason, it's an important subject to understand the activity and hazard of active faults. The active faults in Taiwan are mainly located in the Western Foothills and the Eastern longitudinal <span class="hlt">valley</span>. Active fault distribution map published by the Central Geological Survey (CGS) in 2010 shows that there are 31 active faults in the island of Taiwan and some of which are related to <span class="hlt">earthquake</span>. Many researchers have investigated these active faults and continuously update new data and results, but few people have integrated them for time-dependent <span class="hlt">earthquake</span> hazard assessment. In this study, we want to gather previous researches and field work results and then integrate these data as an active fault parameters table for time-dependent <span class="hlt">earthquake</span> hazard assessment. We are going to gather the seismic profiles or <span class="hlt">earthquake</span> relocation of a fault and then combine the fault trace on land to establish the 3D fault geometry model in GIS system. We collect the researches of fault source scaling in Taiwan and estimate the maximum magnitude from fault length or fault area. We use the characteristic <span class="hlt">earthquake</span> model to evaluate the active fault <span class="hlt">earthquake</span> recurrence interval. In the other parameters, we will collect previous studies or historical references and complete our parameter table of active faults in Taiwan. The WG08 have done the time-dependent <span class="hlt">earthquake</span> hazard assessment of active faults in <span class="hlt">California</span>. They established the fault models, deformation models, <span class="hlt">earthquake</span> rate models, and probability models and then compute the probability of faults in <span class="hlt">California</span>. Following these steps, we have the preliminary evaluated probability of <span class="hlt">earthquake</span>-related hazards in certain</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/1995/4056/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/1995/4056/report.pdf"><span>Precipitation depth-duration and frequency characteristics for Antelope <span class="hlt">Valley</span>, Mojave Desert, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Blodgett, J.C.</p> <p>1995-01-01</p> <p>Methods to evaluate changes in the volume of storm runoff from drainage basins that are likely to be urbanized are needed by land-use planning agencies to establish criteria for the design of flood-control systems. To document the changes in runoff volume of basins that may be urbanized, nine small basins that are considered representative of varying hydrologic conditions in Antelope <span class="hlt">Valley</span>, <span class="hlt">California</span>, were selected for detailed study. Precipitation and stream-gaging stations were established and data were collected for the period 1990-93. The data collected at these U.S. Geological Survey stations were supplemented by data collected at 35 Long-term precipitation stations operated by the National Oceanic and Atmospheric Administration and the Los Angeles County Department of Public Works. These data will be used to calibrate and verify rainfall-runoff models for the nine basins. Results of the model runs will then be used as a guide for estimating basin runoff characteristics throughout Antelope <span class="hlt">Valley</span>. Annual precipitation in Antelope <span class="hlt">Valley</span> ranges from more than 20 inches in the mountains to less than 4 inches on the <span class="hlt">valley</span> floor. Most precipitation in the <span class="hlt">valley</span> falls during the months of December through March, but cyclonic storms in the fall and convectional storms in the summer sometimes occur. The duration of most storms ranges from 1 to 8 days, but most of the precipitation usually occurs within the first 2 days. Many parts of the <span class="hlt">valley</span> have been affected by storms with precipitation depths that equal or exceed 0.60 inch per hour. The storms of January 1943 and March 1983 were the most intense storms of record, with recurrence intervals greater than 100 years in some parts of the <span class="hlt">valley</span>. Depth-duration ratios were calculated by disaggregating daily total precipitation data for intervals of 1, 2, 3, 4, 6, 12, and 18 hours for storms that occurred during 1990-93. The hourly total precipitation data were then disaggregated at 5-minute intervals. A comparison</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70024737','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70024737"><span>Fish communities of the Sacramento River Basin: Implications for conservation of native fishes in the Central <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>May, J.T.; Brown, L.R.</p> <p>2002-01-01</p> <p>The associations of resident fish communities with environmental variables and stream condition were evaluated at representative sites within the Sacramento River Basin, <span class="hlt">California</span> between 1996 and 1998 using multivariate ordination techniques and by calculating six fish community metrics. In addition, the results of the current study were compared with recent studies in the San Joaquin River drainage to provide a wider perspective of the condition of resident fish communities in the Central <span class="hlt">Valley</span> of <span class="hlt">California</span> as a whole. Within the Sacramento drainage, species distributions were correlated with elevational and substrate size gradients; however, the elevation of a sampling site was correlated with a suite of water-quality and habitat variables that are indicative of land use effects on physiochemical stream parameters. Four fish community metrics - percentage of native fish, percentage of intolerant fish, number of tolerant species, and percentage of fish with external anomalies - were responsive to environmental quality. Comparisons between the current study and recent studies in the San Joaquin River drainage suggested that differences in water-management practices may have significant effects on native species fish community structure. Additionally, the results of the current study suggest that index of biotic integrity-type indices can be developed for the Sacramento River Basin and possibly the entire Central <span class="hlt">Valley</span>, <span class="hlt">California</span>. The protection of native fish communities in the Central <span class="hlt">Valley</span> and other arid environments continues to be a conflict between human needs for water resources and the requirements of aquatic ecosystems; preservation of these ecosystems will require innovative management strategies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.S21A2157C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.S21A2157C"><span>Using focal mechanism solutions to correlate <span class="hlt">earthquakes</span> with faults in the Lake Tahoe-Truckee area, <span class="hlt">California</span> and Nevada, and to help design LiDAR surveys for active-fault reconnaissance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cronin, V. S.; Lindsay, R. D.</p> <p>2011-12-01</p> <p>Geomorphic analysis of hillshade images produced from aerial LiDAR data has been successful in identifying youthful fault traces. For example, the recently discovered Polaris fault just northwest of Lake Tahoe, <span class="hlt">California</span>/Nevada, was recognized using LiDAR data that had been acquired by local government to assist land-use planning. Subsequent trenching by consultants under contract to the US Army Corps of Engineers has demonstrated Holocene displacement. The Polaris fault is inferred to be capable of generating a magnitude 6.4-6.9 <span class="hlt">earthquake</span>, based on its apparent length and offset characteristics (Hunter and others, 2011, BSSA 101[3], 1162-1181). Dingler and others (2009, GSA Bull 121[7/8], 1089-1107) describe paleoseismic or geomorphic evidence for late Neogene displacement along other faults in the area, including the West Tahoe-Dollar Point, Stateline-North Tahoe, and Incline Village faults. We have used the seismo-lineament analysis method (SLAM; Cronin and others, 2008, Env Eng Geol 14[3], 199-219) to establish a tentative spatial correlation between each of the previously mentioned faults, as well as with segments of the Dog <span class="hlt">Valley</span> fault system, and one or more <span class="hlt">earthquake(s</span>). The ~18 <span class="hlt">earthquakes</span> we have tentatively correlated with faults in the Tahoe-Truckee area occurred between 1966 and 2008, with magnitudes between 3 and ~6. Given the focal mechanism solution for a well-located shallow-focus <span class="hlt">earthquake</span>, the nodal planes can be projected to Earth's surface as represented by a DEM, plus-or-minus the vertical and horizontal uncertainty in the focal location, to yield two seismo-lineament swaths. The trace of the fault that generated the <span class="hlt">earthquake</span> is likely to be found within one of the two swaths [1] if the fault surface is emergent, and [2] if the fault surface is approximately planar in the vicinity of the focus. Seismo-lineaments from several of the <span class="hlt">earthquakes</span> studied overlap in a manner that suggests they are associated with the same fault. The surface</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22493106','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22493106"><span>Hematology and plasma biochemistry values for the giant garter snake (Thamnophis gigas) and <span class="hlt">valley</span> garter snake (Thamnophis sirtalis fitchi) in the Central <span class="hlt">Valley</span> of <span class="hlt">California</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wack, Raymund F; Hansen, Eric; Small, Marilyn; Poppenga, Robert; Bunn, David; Johnson, Christine K</p> <p>2012-04-01</p> <p>Hematology and plasma biochemistry parameters are useful in the assessment and management of threatened and endangered species. Although reference ranges are readily available for many mammalian species, reference ranges for snakes are lacking for most species. We determined hematology and plasma biochemistry reference ranges for giant garter snakes (Thamnophis gigas) and <span class="hlt">valley</span> garter snakes (Thamnophis sirtalis fitchi) living in four management areas in the Central <span class="hlt">Valley</span> of <span class="hlt">California</span>. White blood cell, heterophil, lymphocyte, and azurophil counts in giant garter snakes were approximately twice the values of <span class="hlt">valley</span> garter snakes. Statistically significant differences in aspartate aminotransferase, globulin, and potassium between the two species did not appear clinically significant. No significant differences were found in the measured parameters between male and female giant garter snakes. Some differences were found among collection sites. These reference ranges provide baseline data for comparisons over time and between collection sites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=SL2-04-179&hterms=Sacramento+CA&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DSacramento%252C%2BCA','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=SL2-04-179&hterms=Sacramento+CA&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DSacramento%252C%2BCA"><span>Sacramento <span class="hlt">Valley</span>, CA, USA</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1973-01-01</p> <p>The Sacramento <span class="hlt">Valley</span> (40.5N, 121.5W) of <span class="hlt">California</span> is the northern extension of the Central <span class="hlt">Valley</span>, main agriculture region of the state. Hundreds of truck farms, vineyards and orchards can be seen throughout the length and breadth of the <span class="hlt">valley</span> which was reclaimed from the desert by means of intensive and extensive irrigation projects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.H23H1397C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.H23H1397C"><span>Subsidence due to Excessive Groundwater Withdrawal in the San Joaquin <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Corbett, F.; Harter, T.; Sneed, M.</p> <p>2011-12-01</p> <p>Francis Corbett1, Thomas Harter1 and Michelle Sneed2 1Department of Land Air and Water Resources, University of <span class="hlt">California</span>, Davis. 2U.S. Geological Survey Western Remote Sensing and Visualization Center, Sacramento. Abstract: Groundwater development within the Central <span class="hlt">Valley</span> of <span class="hlt">California</span> began approximately a century ago. Water was needed to supplement limited surface water supplies for the burgeoning population and agricultural industries, especially within the arid but fertile San Joaquin <span class="hlt">Valley</span>. Groundwater levels have recovered only partially during wet years from drought-induced lows creating long-term groundwater storage overdraft. Surface water deliveries from Federal and State sources led to a partial alleviation of these pressure head declines from the late 1960s. However, in recent decades, surface water deliveries have declined owing to increasing environmental pressures, whilst water demands have remained steady. Today, a large portion of the San Joaquin <span class="hlt">Valley</span> population, and especially agriculture, rely upon groundwater. Groundwater levels are again rapidly declining except in wet years. There is significant concern that subsidence due to groundwater withdrawal, first observed at a large scale in the middle 20th century, will resume as groundwater resources continue to be depleted. Previous subsidence has led to problems such as infrastructure damage and flooding. To provide a support tool for groundwater management on a naval air station in the southern San Joaquin <span class="hlt">Valley</span> (Tulare Lake Basin), a one-dimensional MODFLOW subsidence model covering the period 1925 to 2010 was developed incorporating extensive reconstruction of historical subsidence and water level data from various sources. The stratigraphy used for model input was interpreted from geophysical logs and well completion reports. Gaining good quality data proved problematic, and often values needed to be estimated. In part, this was due to the historical lack of awareness/understanding of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.S13C2020Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.S13C2020Y"><span>Products and Services Available from the Southern <span class="hlt">California</span> <span class="hlt">Earthquake</span> Data Center (SCEDC) and the Southern <span class="hlt">California</span> Seismic Network (SCSN)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yu, E.; Bhaskaran, A.; Chen, S.; Chowdhury, F. R.; Meisenhelter, S.; Hutton, K.; Given, D.; Hauksson, E.; Clayton, R. W.</p> <p>2010-12-01</p> <p>Currently the SCEDC archives continuous and triggered data from nearly 5000 data channels from 425 SCSN recorded stations, processing and archiving an average of 12,000 <span class="hlt">earthquakes</span> each year. The SCEDC provides public access to these <span class="hlt">earthquake</span> parametric and waveform data through its website www.data.scec.org and through client applications such as STP and DHI. This poster will describe the most significant developments at the SCEDC in the past year. Updated hardware: ● The SCEDC has more than doubled its waveform file storage capacity by migrating to 2 TB disks. New data holdings: ● Waveform data: Beginning Jan 1, 2010 the SCEDC began continuously archiving all high-sample-rate strong-motion channels. All seismic channels recorded by SCSN are now continuously archived and available at SCEDC. ● Portable data from El Mayor Cucapah 7.2 sequence: Seismic waveforms from portable stations installed by researchers (contributed by Elizabeth Cochran, Jamie Steidl, and Octavio Lazaro-Mancilla) have been added to the archive and are accessible through STP either as continuous data or associated with events in the SCEDC <span class="hlt">earthquake</span> catalog. This additional data will help SCSN analysts and researchers improve event locations from the sequence. ● Real time GPS solutions from El Mayor Cucapah 7.2 event: Three component 1Hz seismograms of <span class="hlt">California</span> Real Time Network (CRTN) GPS stations, from the April 4, 2010, magnitude 7.2 El Mayor-Cucapah <span class="hlt">earthquake</span> are available in SAC format at the SCEDC. These time series were created by Brendan Crowell, Yehuda Bock, the project PI, and Mindy Squibb at SOPAC using data from the CRTN. The El Mayor-Cucapah <span class="hlt">earthquake</span> demonstrated definitively the power of real-time high-rate GPS data: they measure dynamic displacements directly, they do not clip and they are also able to detect the permanent (coseismic) surface deformation. ● Triggered data from the Quake Catcher Network (QCN) and Community Seismic Network (CSN): The SCEDC in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.earthquakeconference.org','SCIGOVWS'); return false;" href="http://www.earthquakeconference.org"><span>2016 National <span class="hlt">Earthquake</span> Conference</span></a></p> <p><a target="_blank" href="http://www.science.gov/aboutsearch.html">Science.gov Websites</a></p> <p></p> <p></p> <p>Thank you to our Presenting Sponsor, <span class="hlt">California</span> <em><span class="hlt">Earthquake</span></em> Authority. What's New? What's Next ? What's Your Role in Building a National Strategy? The National <em><span class="hlt">Earthquake</span></em> Conference (NEC) is a , state government leaders, social science practitioners, U.S. State and Territorial <em><span class="hlt">Earthquake</span></em> Managers</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70178933','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70178933"><span>Hydrogeologic framework of the Santa Clara <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hanson, Randall T.</p> <p>2015-01-01</p> <p>The hydrologic framework of the Santa Clara <span class="hlt">Valley</span> in northern <span class="hlt">California</span> was redefined on the basis of new data and a new hydrologic model. The regional groundwater flow systems can be subdivided into upper-aquifer and lower-aquifer systems that form a convergent flow system within a basin bounded by mountains and hills on three sides and discharge to pumping wells and the southern San Francisco Bay. Faults also control the flow of groundwater within the Santa Clara <span class="hlt">Valley</span> and subdivide the aquifer system into three subregions.After decades of development and groundwater depletion that resulted in substantial land subsidence, Santa Clara <span class="hlt">Valley</span> Water District (SCVWD) and the local water purveyors have refilled the basin through conservation and importation of water for direct use and artificial recharge. The natural flow system has been altered by extensive development with flow paths toward major well fields. Climate has not only affected the cycles of sedimentation during the glacial periods over the past million years, but interannual to interdecadal climate cycles also have affected the supply and demand components of the natural and anthropogenic inflows and outflows of water in the <span class="hlt">valley</span>. Streamflow has been affected by development of the aquifer system and regulated flow from reservoirs, as well as conjunctive use of groundwater and surface water. Interaquifer flow through water-supply wells screened across multiple aquifers is an important component to the flow of groundwater and recapture of artificial recharge in the Santa Clara <span class="hlt">Valley</span>. Wellbore flow and depth-dependent chemical and isotopic data indicate that flow into wells from multiple aquifers, as well as capture of artificial recharge by pumping of water-supply wells, predominantly is occurring in the upper 500 ft (152 m) of the aquifer system. Artificial recharge represents about one-half of the inflow of water into the <span class="hlt">valley</span> for the period 1970–1999. Most subsidence is occurring below 250 ft</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V13G2695D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V13G2695D"><span>Mammoth Mountain, <span class="hlt">California</span> broadband seismic experiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dawson, P. B.; Pitt, A. M.; Wilkinson, S. K.; Chouet, B. A.; Hill, D. P.; Mangan, M.; Prejean, S. G.; Read, C.; Shelly, D. R.</p> <p>2013-12-01</p> <p>Mammoth Mountain is a young cumulo-volcano located on the southwest rim of Long <span class="hlt">Valley</span> caldera, <span class="hlt">California</span>. Current volcanic processes beneath Mammoth Mountain are manifested in a wide range of seismic signals, including swarms of shallow volcano-tectonic <span class="hlt">earthquakes</span>, upper and mid-crustal long-period <span class="hlt">earthquakes</span>, swarms of brittle-failure <span class="hlt">earthquakes</span> in the lower crust, and shallow (3-km depth) very-long-period <span class="hlt">earthquakes</span>. Diffuse emissions of C02 began after a magmatic dike injection beneath the volcano in 1989, and continue to present time. These indications of volcanic unrest drive an extensive monitoring effort of the volcano by the USGS Volcano Hazards Program. As part of this effort, eleven broadband seismometers were deployed on Mammoth Mountain in November 2011. This temporary deployment is expected to run through the fall of 2013. These stations supplement the local short-period and broadband seismic stations of the Northern <span class="hlt">California</span> Seismic Network (NCSN) and provide a combined network of eighteen broadband stations operating within 4 km of the summit of Mammoth Mountain. Data from the temporary stations are not available in real-time, requiring the merging of the data from the temporary and permanent networks, timing of phases, and relocation of seismic events to be accomplished outside of the standard NCSN processing scheme. The timing of phases is accomplished through an interactive Java-based phase-picking routine, and the relocation of seismicity is achieved using the probabilistic non-linear software package NonLinLoc, distributed under the GNU General Public License by Alomax Scientific. Several swarms of shallow volcano-tectonic <span class="hlt">earthquakes</span>, spasmodic bursts of high-frequency <span class="hlt">earthquakes</span>, a few long-period events located within or below the edifice of Mammoth Mountain and numerous mid-crustal long-period events have been recorded by the network. To date, about 900 of the ~2400 events occurring beneath Mammoth Mountain since November 2011 have</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70036440','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70036440"><span>Migrating swarms of brittle-failure <span class="hlt">earthquakes</span> in the lower crust beneath Mammoth Mountain, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Shelly, D.R.; Hill, D.P.</p> <p>2011-01-01</p> <p>Brittle-failure <span class="hlt">earthquakes</span> in the lower crust, where high pressures and temperatures would typically promote ductile deformation, are relatively rare but occasionally observed beneath active volcanic centers. Where they occur, these <span class="hlt">earthquakes</span> provide a rare opportunity to observe volcanic processes in the lower crust, such as fluid injection and migration, which may induce brittle faulting under these conditions. Here, we examine recent short-duration <span class="hlt">earthquake</span> swarms deep beneath the southwestern margin of Long <span class="hlt">Valley</span> Caldera, near Mammoth Mountain. We focus in particular on a swarm that occurred September 29-30, 2009. To maximally illuminate the spatial-temporal progression, we supplement catalog events by detecting additional small events with similar waveforms in the continuous data, achieving up to a 10-fold increase in the number of locatable events. We then relocate all events, using cross-correlation and a double-difference algorithm. We find that the 2009 swarm exhibits systematically decelerating upward migration, with hypocenters shallowing from 21 to 19 km depth over approximately 12 hours. This relatively high migration rate, combined with a modest maximum magnitude of 1.4 in this swarm, suggests the trigger might be ascending CO2 released from underlying magma.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70024789','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70024789"><span>The 1999 Mw 7.1 Hector Mine, <span class="hlt">California</span>, <span class="hlt">earthquake</span>: A test of the stress shadow hypothesis?</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Harris, R.A.; Simpson, R.W.</p> <p>2002-01-01</p> <p>We test the stress shadow hypothesis for large <span class="hlt">earthquake</span> interactions by examining the relationship between two large <span class="hlt">earthquakes</span> that occurred in the Mojave Desert of southern <span class="hlt">California</span>, the 1992 Mw 7.3 Landers and 1999 Mw 7.1 Hector Mine <span class="hlt">earthquakes</span>. We want to determine if the 1999 Hector Mine <span class="hlt">earthquake</span> occurred at a location where the Coulomb stress was increased (<span class="hlt">earthquake</span> advance, stress trigger) or decreased (<span class="hlt">earthquake</span> delay, stress shadow) by the previous large <span class="hlt">earthquake</span>. Using four models of the Landers rupture and a range of possible hypocentral planes for the Hector Mine <span class="hlt">earthquake</span>, we discover that most scenarios yield a Landers-induced relaxation (stress shadow) on the Hector Mine hypocentral plane. Although this result would seem to weigh against the stress shadow hypothesis, the results become considerably more uncertain when the effects of a nearby Landers aftershock, the 1992 ML 5.4 Pisgah <span class="hlt">earthquake</span>, are taken into account. We calculate the combined static Coulomb stress changes due to the Landers and Pisgah <span class="hlt">earthquakes</span> to range from -0.3 to +0.3 MPa (- 3 to +3 bars) at the possible Hector Mine hypocenters, depending on choice of rupture model and hypocenter. These varied results imply that the Hector Mine <span class="hlt">earthquake</span> does not provide a good test of the stress shadow hypothesis for large <span class="hlt">earthquake</span> interactions. We use a simple approach, that of static dislocations in an elastic half-space, yet we still obtain a wide range of both negative and positive Coulomb stress changes. Our findings serve as a caution that more complex models purporting to explain the triggering or shadowing relationship between the 1992 Landers and 1999 Hector Mine <span class="hlt">earthquakes</span> need to also consider the parametric and geometric uncertainties raised here.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70176033','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70176033"><span>Spatial-temporal variation of low-frequency <span class="hlt">earthquake</span> bursts near Parkfield, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wu, Chunquan; Guyer, Robert; Shelly, David R.; Trugman, D.; Frank, William; Gomberg, Joan S.; Johnson, P.</p> <p>2015-01-01</p> <p>Tectonic tremor (TT) and low-frequency <span class="hlt">earthquakes</span> (LFEs) have been found in the deeper crust of various tectonic environments globally in the last decade. The spatial-temporal behaviour of LFEs provides insight into deep fault zone processes. In this study, we examine recurrence times from a 12-yr catalogue of 88 LFE families with ∼730 000 LFEs in the vicinity of the Parkfield section of the San Andreas Fault (SAF) in central <span class="hlt">California</span>. We apply an automatic burst detection algorithm to the LFE recurrence times to identify the clustering behaviour of LFEs (LFE bursts) in each family. We find that the burst behaviours in the northern and southern LFE groups differ. Generally, the northern group has longer burst duration but fewer LFEs per burst, while the southern group has shorter burst duration but more LFEs per burst. The southern group LFE bursts are generally more correlated than the northern group, suggesting more coherent deep fault slip and relatively simpler deep fault structure beneath the locked section of SAF. We also found that the 2004 Parkfield <span class="hlt">earthquake</span> clearly increased the number of LFEs per burst and average burst duration for both the northern and the southern groups, with a relatively larger effect on the northern group. This could be due to the weakness of northern part of the fault, or the northwesterly rupture direction of the Parkfield <span class="hlt">earthquake</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70021052','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70021052"><span>Integration of high-resolution seismic and aeromagnetic data for <span class="hlt">earthquake</span> hazards evaluations: An example from the Willamette <span class="hlt">Valley</span>, Oregon</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Liberty, L.M.; Trehu, A.M.; Blakely, R.J.; Dougherty, M.E.</p> <p>1999-01-01</p> <p>Aeromagnetic and high-resolution seismic reflection data were integrated to place constraints on the history of seismic activity and to determine the continuity of the possibly active, yet largely concealed Mount Angel fault in the Willamette <span class="hlt">Valley</span>, Oregon. Recent seismic activity possibly related to the 20-km-long fault includes a swarm of small <span class="hlt">earthquakes</span> near Woodburn in 1990 and the magnitude 5.6 Scotts Mills <span class="hlt">earthquake</span> in 1993. Newly acquired aeromagnetic data show several large northwest-trending anomalies, including one associated with the Mount Angel fault. The magnetic signature indicates that the fault may actually extend 70 km across the Willamette <span class="hlt">Valley</span> to join the Newberg and Gales Creek faults in the Oregon Coast Range. We collected 24-fold high-resolution seismic reflection data along two transects near Woodburn, Oregon, to image the offset of the Miocene-age Columbia River Basalts (CRB) and overlying sediments at and northwest of the known mapped extent of the Mount Angel fault. The seismic data show a 100-200-m offset in the CRB reflector at depths from 300 to 700 m. Folded or offset sediments appear above the CRB with decreasing amplitude to depths as shallow as were imaged (approximately 40 m). Modeling experiments based on the magnetic data indicate, however, that the anomaly associated with the Mount Angel fault is not caused solely by an offset of the CRB and overlying sediments. Underlying magnetic sources, which we presume to be volcanic rocks of the Siletz terrane, must have vertical offsets of at least 500 m to fit the observed data. We conclude that the Mount Angel fault appears to have been active since Eocene age and that the Gales Creek, Newberg, and Mount Angel faults should be considered a single potentially active fault system. This fault, as well as other parallel northwest-trending faults in the Willamette <span class="hlt">Valley</span>, should be considered as risks for future potentially damaging <span class="hlt">earthquakes</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70025135','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70025135"><span>Relations between seismicity and deformation during unrest in Long <span class="hlt">Valley</span> Caldera, <span class="hlt">California</span>, from 1995 through 1999</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hill, D.P.; Langbein, J.O.; Prejean, S.</p> <p>2003-01-01</p> <p>Unrest in Long <span class="hlt">Valley</span> Caldera and the adjacent Sierra Nevada from 1995 through 2000 was dominated by three major episodes: (1) the March-April 1996 <span class="hlt">earthquake</span> swarm in the east lobe of the south moat; (2) the July 1997-January 1998 caldera-wide unrest; and (3) a sequence of three M>5 <span class="hlt">earthquakes</span> (9 June 1998, 13 July 1998, and 15 May 1999 UT) located in the Sierra Nevada block immediately south of the caldera. These three unrest episodes each had distinct characteristics with distinct implications for associated hazards. Seismicity developed as <span class="hlt">earthquake</span> swarms for the 1996 and 1997-98 episodes, both of which were within the caldera. In contrast, the series of three M>5 <span class="hlt">earthquakes</span> south of the caldera in 1998-99 each developed as a mainshock-aftershock sequence. Marginal deformation within the caldera associated with the 1996 swarm and the 1998-99 M>5 <span class="hlt">earthquakes</span> is consistent with the cumulative seismic moments for the respective sequences. Deformation associated with the 1997-98 episode, however, was roughly five times larger than can be accounted for by the cumulative seismic moment of the associated <span class="hlt">earthquake</span> swarm. We conclude that the 1997-98 episode was associated with mass transport (local intrusion of magma or magmatic brine) and that the associated <span class="hlt">earthquake</span> swarm activity, which had a relatively high b -value of 1.2, was largely driven by the intrusive process. In contrast, the 1996 <span class="hlt">earthquake</span> swarm and the 1998-99 M>5 mainshock-aftershock sequences, both with 'normal' b -values of ???0.9, represent brittle relaxation to previously accumulated stresses associated with little or no mass transport. These relations emphasize the importance of simultaneous, real-time monitoring of both seismicity and deformation as a basis for judging whether an evolving unrest episode has the potential for culminating in a volcanic eruption. ?? 2003 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA01757.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA01757.html"><span>Space Radar Image of Long <span class="hlt">Valley</span>, <span class="hlt">California</span> - 3-D view</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>1999-05-01</p> <p>This is a three-dimensional perspective view of Long <span class="hlt">Valley</span>, <span class="hlt">California</span> by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar on board the space shuttle Endeavour. This view was constructed by overlaying a color composite SIR-C image on a digital elevation map. The digital elevation map was produced using radar interferometry, a process by which radar data are acquired on different passes of the space shuttle and, which then, are compared to obtain elevation information. The data were acquired on April 13, 1994 and on October 3, 1994, during the first and second flights of the SIR-C/X-SAR radar instrument. The color composite radar image was produced by assigning red to the C-band (horizontally transmitted and vertically received) polarization; green to the C-band (vertically transmitted and received) polarization; and blue to the ratio of the two data sets. Blue areas in the image are smooth and yellow areas are rock outcrops with varying amounts of snow and vegetation. The view is looking north along the northeastern edge of the Long <span class="hlt">Valley</span> caldera, a volcanic collapse feature created 750,000 years ago and the site of continued subsurface activity. Crowley Lake is off the image to the left. http://photojournal.jpl.nasa.gov/catalog/PIA01757</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.S52A0127J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.S52A0127J"><span>Finite Moment Tensors of Southern <span class="hlt">California</span> <span class="hlt">Earthquakes</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jordan, T. H.; Chen, P.; Zhao, L.</p> <p>2003-12-01</p> <p>We have developed procedures for inverting broadband waveforms for the finite moment tensors (FMTs) of regional <span class="hlt">earthquakes</span>. The FMT is defined in terms of second-order polynomial moments of the source space-time function and provides the lowest order representation of a finite fault rupture; it removes the fault-plane ambiguity of the centroid moment tensor (CMT) and yields several additional parameters of seismological interest: the characteristic length L{c}, width W{c}, and duration T{c} of the faulting, as well as the directivity vector {v}{d} of the fault slip. To formulate the inverse problem, we follow and extend the methods of McGuire et al. [2001, 2002], who have successfully recovered the second-order moments of large <span class="hlt">earthquakes</span> using low-frequency teleseismic data. We express the Fourier spectra of a synthetic point-source waveform in its exponential (Rytov) form and represent the observed waveform relative to the synthetic in terms two frequency-dependent differential times, a phase delay δ τ {p}(ω ) and an amplitude-reduction time δ τ {q}(ω ), which we measure using Gee and Jordan's [1992] isolation-filter technique. We numerically calculate the FMT partial derivatives in terms of second-order spatiotemporal gradients, which allows us to use 3D finite-difference seismograms as our isolation filters. We have applied our methodology to a set of small to medium-sized <span class="hlt">earthquakes</span> in Southern <span class="hlt">California</span>. The errors in anelastic structure introduced perturbations larger than the signal level caused by finite source effect. We have therefore employed a joint inversion technique that recovers the CMT parameters of the aftershocks, as well as the CMT and FMT parameters of the mainshock, under the assumption that the source finiteness of the aftershocks can be ignored. The joint system of equations relating the δ τ {p} and δ τ {q} data to the source parameters of the mainshock-aftershock cluster is denuisanced for path anomalies in both observables</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.S33F4938J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.S33F4938J"><span>The 2014 Mw 6.0 Napa <span class="hlt">Earthquake</span>, <span class="hlt">California</span>: Observations from Real-time GPS-enhanced <span class="hlt">Earthquake</span> Early Warning</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Johanson, I. A.; Grapenthin, R.; Allen, R. M.</p> <p>2014-12-01</p> <p>Recently, progress has been made to demonstrate feasibility and benefits of including real-time GPS (rtGPS) in <span class="hlt">earthquake</span> early warning and rapid response systems. While most concepts have yet to be integrated into operational environments, the Berkeley Seismological Laboratory is currently running an rtGPS based finite fault inversion scheme in true real-time, which is triggered by the seismic-based ShakeAlert system and then sends updated <span class="hlt">earthquake</span> alerts to a test receiver. The Geodetic Alarm System (G-larmS) was online and responded to the 2014 Mw6.0 South Napa <span class="hlt">earthquake</span> in <span class="hlt">California</span>. We review G-larmS' performance during this event and for 13 aftershocks, and we present rtGPS observations and real-time modeling results for the main shock. The first distributed slip model and a magnitude estimate of Mw5.5 were available 24 s after the event origin time, which could be reduced to 14 s after a bug fix (~8 s S-wave travel time, ~6 s data latency). The system continued to re-estimate the magnitude once every second: it increased to Mw5.9 3 s after the first alert and stabilized at Mw5.8 after 15 s. G-larmS' solutions for the subsequent small magnitude aftershocks demonstrate that Mw~6.0 is the current limit for alert updates to contribute back to the seismic-based early warning system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018CG....115..198A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018CG....115..198A"><span><span class="hlt">Earthquake</span> prediction in <span class="hlt">California</span> using regression algorithms and cloud-based big data infrastructure</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Asencio-Cortés, G.; Morales-Esteban, A.; Shang, X.; Martínez-Álvarez, F.</p> <p>2018-06-01</p> <p><span class="hlt">Earthquake</span> magnitude prediction is a challenging problem that has been widely studied during the last decades. Statistical, geophysical and machine learning approaches can be found in literature, with no particularly satisfactory results. In recent years, powerful computational techniques to analyze big data have emerged, making possible the analysis of massive datasets. These new methods make use of physical resources like cloud based architectures. <span class="hlt">California</span> is known for being one of the regions with highest seismic activity in the world and many data are available. In this work, the use of several regression algorithms combined with ensemble learning is explored in the context of big data (1 GB catalog is used), in order to predict <span class="hlt">earthquakes</span> magnitude within the next seven days. Apache Spark framework, H2 O library in R language and Amazon cloud infrastructure were been used, reporting very promising results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23423771','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23423771"><span>Seroprevalence of Hepatitis B and C Infections among Healthy Volunteer Blood Donors in the Central <span class="hlt">California</span> <span class="hlt">Valley</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sheikh, Muhammad Y; Atla, Pradeep R; Ameer, Adnan; Sadiq, Humaira; Sadler, Patrick C</p> <p>2013-01-01</p> <p>The Central <span class="hlt">California</span> <span class="hlt">Valley</span> has a diverse population with significant proportions of Hispanics and Asians. This cross-sectional study was conducted to evaluate the prevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) in healthy blood donors in the <span class="hlt">Valley</span>. A total of 217,738 voluntary blood donors were identified between 2006 and 2010 (36,795 first-time donors; 180,943 repeat donors). Among the first-time donors, the HBV and HCV prevalence was 0.28% and 0.52%, respectively. Higher HBV prevalence seen in Asians (3%) followed by Caucasians (0.05%), African Americans (0.15%), and Hispanics (0.05%). Hmong had a HBV prevalence of 7.63% with a peak prevalence of 8.76% among the 16- to 35-year-old age group. Highest HCV prevalence in Native Americans (2.8) followed by Caucasians (0.59%), Hispanics (0.45%), African Americans (0.38%), and Asians (0.2%). Ethnic disparities persist with regard to the prevalence of HBV and HCV in the Central <span class="hlt">California</span> <span class="hlt">Valley</span>. The reported prevalence may be an underestimate because our study enrolled healthy volunteer blood donors only. The development of aggressive public health measures to evaluate the true prevalence of HBV and HCV and to identify those in need of HBV and HCV prevention measures and therapy is critically important.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3572322','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3572322"><span>Seroprevalence of Hepatitis B and C Infections among Healthy Volunteer Blood Donors in the Central <span class="hlt">California</span> <span class="hlt">Valley</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Atla, Pradeep R.; Ameer, Adnan; Sadiq, Humaira; Sadler, Patrick C.</p> <p>2013-01-01</p> <p>Background/Aims The Central <span class="hlt">California</span> <span class="hlt">Valley</span> has a diverse population with significant proportions of Hispanics and Asians. This cross-sectional study was conducted to evaluate the prevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) in healthy blood donors in the <span class="hlt">Valley</span>. Methods A total of 217,738 voluntary blood donors were identified between 2006 and 2010 (36,795 first-time donors; 180,943 repeat donors). Results Among the first-time donors, the HBV and HCV prevalence was 0.28% and 0.52%, respectively. Higher HBV prevalence seen in Asians (3%) followed by Caucasians (0.05%), African Americans (0.15%), and Hispanics (0.05%). Hmong had a HBV prevalence of 7.63% with a peak prevalence of 8.76% among the 16- to 35-year-old age group. Highest HCV prevalence in Native Americans (2.8) followed by Caucasians (0.59%), Hispanics (0.45%), African Americans (0.38%), and Asians (0.2%). Conclusions Ethnic disparities persist with regard to the prevalence of HBV and HCV in the Central <span class="hlt">California</span> <span class="hlt">Valley</span>. The reported prevalence may be an underestimate because our study enrolled healthy volunteer blood donors only. The development of aggressive public health measures to evaluate the true prevalence of HBV and HCV and to identify those in need of HBV and HCV prevention measures and therapy is critically important. PMID:23423771</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70193722','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70193722"><span>A new strategy for <span class="hlt">earthquake</span> focal mechanisms using waveform-correlation-derived relative polarities and cluster analysis: Application to the 2014 Long <span class="hlt">Valley</span> Caldera <span class="hlt">earthquake</span> swarm</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Shelly, David R.; Hardebeck, Jeanne L.; Ellsworth, William L.; Hill, David P.</p> <p>2016-01-01</p> <p>In microseismicity analyses, reliable focal mechanisms can typically be obtained for only a small subset of located events. We address this limitation here, presenting a framework for determining robust focal mechanisms for entire populations of very small events. To achieve this, we resolve relative P and S wave polarities between pairs of waveforms by using their signed correlation coefficients—a by-product of previously performed precise <span class="hlt">earthquake</span> relocation. We then use cluster analysis to group events with similar patterns of polarities across the network. Finally, we apply a standard mechanism inversion to the grouped data, using either catalog or correlation-derived P wave polarity data sets. This approach has great potential for enhancing analyses of spatially concentrated microseismicity such as <span class="hlt">earthquake</span> swarms, mainshock-aftershock sequences, and industrial reservoir stimulation or injection-induced seismic sequences. To demonstrate its utility, we apply this technique to the 2014 Long <span class="hlt">Valley</span> Caldera <span class="hlt">earthquake</span> swarm. In our analysis, 85% of the events (7212 out of 8494 located by Shelly et al. [2016]) fall within five well-constrained mechanism clusters, more than 12 times the number with network-determined mechanisms. Of the <span class="hlt">earthquakes</span> we characterize, 3023 (42%) have magnitudes smaller than 0.0. We find that mechanism variations are strongly associated with corresponding hypocentral structure, yet mechanism heterogeneity also occurs where it cannot be resolved by hypocentral patterns, often confined to small-magnitude events. Small (5–20°) rotations between mechanism orientations and <span class="hlt">earthquake</span> location trends persist when we apply 3-D velocity models and might reflect a geometry of en echelon, interlinked shear, and dilational faulting.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2003/0449/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2003/0449/"><span>Photomosaics and logs of trenches on the San Andreas Fault, Thousand Palms Oasis, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fumal, Thomas E.; Frost, William T.; Garvin, Christopher; Hamilton, John C.; Jaasma, Monique; Rymer, Michael J.</p> <p>2004-01-01</p> <p>We present photomosaics and logs of the walls of trenches excavated for a paleoseismic study at Thousand Palms Oasis (Fig. 1). The site is located on the Mission Creek strand of the San Andreas fault zone, one of two major active strands of the fault in the Indio Hills along the northeast margin of the Coachella <span class="hlt">Valley</span> (Fig. 2). The Coachella <span class="hlt">Valley</span> section is the most poorly understood major part of the San Andreas fault with regard to slip rate and timing of past large-magnitude <span class="hlt">earthquakes</span>, and therefore <span class="hlt">earthquake</span> hazard. No large <span class="hlt">earthquakes</span> have occurred for more than three centuries, the longest elapsed time for any part of the southern San Andreas fault. In spite of this, the Working Group on <span class="hlt">California</span> <span class="hlt">Earthquake</span> Probabilities (1995) assigned the lowest 30-year conditional probability on the southern San Andreas fault to the Coachella <span class="hlt">Valley</span>. Models of the behavior of this part of the fault, however, have been based on very limited geologic data. The Thousand Palms Oasis is an attractive location for paleoseismic study primarily because of the well-bedded late Holocene sedimentary deposits with abundant layers of organic matter for radiocarbon dating necessary to constrain the timing of large prehistoric <span class="hlt">earthquakes</span>. Previous attempts to develop a chronology of paleoearthquakes for the region have been hindered by the scarcity of in-situ 14C-dateable material for age control in this desert environment. Also, the fault in the vicinity of Thousand Palms Oasis consists of a single trace that is well expressed, both geomorphically and as a vegetation lineament (Figs. 2, 3). Results of our investigations are discussed in Fumal et al. (2002) and indicate that four and probably five surface-rupturing <span class="hlt">earthquakes</span> occurred along this part of the fault during the past 1200 years. The average recurrence time for these <span class="hlt">earthquakes</span> is 215 ± 25 years, although interevent times may have been as short as a few decades or as long as 400 years. Thus, although the elapsed</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ERL....12h4009K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ERL....12h4009K"><span>Availability of high-magnitude streamflow for groundwater banking in the Central <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kocis, Tiffany N.; Dahlke, Helen E.</p> <p>2017-08-01</p> <p>California’s climate is characterized by the largest precipitation and streamflow variability observed within the conterminous US This, combined with chronic groundwater overdraft of 0.6-3.5 km3 yr-1, creates the need to identify additional surface water sources available for groundwater recharge using methods such as agricultural groundwater banking, aquifer storage and recovery, and spreading basins. High-magnitude streamflow, i.e. flow above the 90th percentile, that exceeds environmental flow requirements and current surface water allocations under <span class="hlt">California</span> water rights, could be a viable source of surface water for groundwater banking. Here, we present a comprehensive analysis of the magnitude, frequency, duration and timing of high-magnitude streamflow (HMF) for 93 stream gauges covering the Sacramento, San Joaquin and Tulare basins in <span class="hlt">California</span>. The results show that in an average year with HMF approximately 3.2 km3 of high-magnitude flow is exported from the entire Central <span class="hlt">Valley</span> to the Sacramento-San Joaquin Delta often at times when environmental flow requirements of the Delta and major rivers are exceeded. High-magnitude flow occurs, on average, during 7 and 4.7 out of 10 years in the Sacramento River and the San Joaquin-Tulare Basins, respectively, from just a few storm events (5-7 1-day peak events) lasting for 25-30 days between November and April. The results suggest that there is sufficient unmanaged surface water physically available to mitigate long-term groundwater overdraft in the Central <span class="hlt">Valley</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2011-03-15/pdf/2011-5883.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2011-03-15/pdf/2011-5883.pdf"><span>76 FR 14047 - Notice of Intent to Repatriate Cultural Items: <span class="hlt">California</span> Department of Transportation (Caltrans...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2011-03-15</p> <p>... of <span class="hlt">California</span>; <span class="hlt">California</span> <span class="hlt">Valley</span> Miwok Tribe, <span class="hlt">California</span>; Chicken Ranch Rancheria of Me-Wuk Indians...; <span class="hlt">California</span> <span class="hlt">Valley</span> Miwok Tribe, <span class="hlt">California</span>; Chicken Ranch Rancheria of Me-Wuk Indians of <span class="hlt">California</span>; Ione Band...; <span class="hlt">California</span> <span class="hlt">Valley</span> Miwok Tribe, <span class="hlt">California</span>; Chicken Ranch Rancheria of Me-Wuk Indians of <span class="hlt">California</span>; Ione Band...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2004/1083/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2004/1083/"><span>Cross-sections and maps showing double-difference relocated <span class="hlt">earthquakes</span> from 1984-2000 along the Hayward and Calaveras faults, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Simpson, Robert W.; Graymer, Russell W.; Jachens, Robert C.; Ponce, David A.; Wentworth, Carl M.</p> <p>2004-01-01</p> <p>We present cross-section and map views of <span class="hlt">earthquakes</span> that occurred from 1984 to 2000 in the vicinity of the Hayward and Calaveras faults in the San Francisco Bay region, <span class="hlt">California</span>. These <span class="hlt">earthquakes</span> came from a catalog of events relocated using the double-difference technique, which provides superior relative locations of nearby events. As a result, structures such as fault surfaces and alignments of events along these surfaces are more sharply defined than in previous catalogs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ACP....14.4955G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ACP....14.4955G"><span>Emissions of organic carbon and methane from petroleum and dairy operations in <span class="hlt">California</span>'s San Joaquin <span class="hlt">Valley</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gentner, D. R.; Ford, T. B.; Guha, A.; Boulanger, K.; Brioude, J.; Angevine, W. M.; de Gouw, J. A.; Warneke, C.; Gilman, J. B.; Ryerson, T. B.; Peischl, J.; Meinardi, S.; Blake, D. R.; Atlas, E.; Lonneman, W. A.; Kleindienst, T. E.; Beaver, M. R.; St. Clair, J. M.; Wennberg, P. O.; VandenBoer, T. C.; Markovic, M. Z.; Murphy, J. G.; Harley, R. A.; Goldstein, A. H.</p> <p>2014-05-01</p> <p>Petroleum and dairy operations are prominent sources of gas-phase organic compounds in <span class="hlt">California</span>'s San Joaquin <span class="hlt">Valley</span>. It is essential to understand the emissions and air quality impacts of these relatively understudied sources, especially for oil/gas operations in light of increasing US production. Ground site measurements in Bakersfield and regional aircraft measurements of reactive gas-phase organic compounds and methane were part of the CalNex (<span class="hlt">California</span> Research at the Nexus of Air Quality and Climate Change) project to determine the sources contributing to regional gas-phase organic carbon emissions. Using a combination of near-source and downwind data, we assess the composition and magnitude of emissions, and provide average source profiles. To examine the spatial distribution of emissions in the San Joaquin <span class="hlt">Valley</span>, we developed a statistical modeling method using ground-based data and the FLEXPART-WRF transport and meteorological model. We present evidence for large sources of paraffinic hydrocarbons from petroleum operations and oxygenated compounds from dairy (and other cattle) operations. In addition to the small straight-chain alkanes typically associated with petroleum operations, we observed a wide range of branched and cyclic alkanes, most of which have limited previous in situ measurements or characterization in petroleum operation emissions. Observed dairy emissions were dominated by ethanol, methanol, acetic acid, and methane. Dairy operations were responsible for the vast majority of methane emissions in the San Joaquin <span class="hlt">Valley</span>; observations of methane were well correlated with non-vehicular ethanol, and multiple assessments of the spatial distribution of emissions in the San Joaquin <span class="hlt">Valley</span> highlight the dominance of dairy operations for methane emissions. The petroleum operations source profile was developed using the composition of non-methane hydrocarbons in unrefined natural gas associated with crude oil. The observed source profile is</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.S31C2778S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.S31C2778S"><span>Expanding CyberShake Physics-Based Seismic Hazard Calculations to Central <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Silva, F.; Callaghan, S.; Maechling, P. J.; Goulet, C. A.; Milner, K. R.; Graves, R. W.; Olsen, K. B.; Jordan, T. H.</p> <p>2016-12-01</p> <p>As part of its program of <span class="hlt">earthquake</span> system science, the Southern <span class="hlt">California</span> <span class="hlt">Earthquake</span> Center (SCEC) has developed a simulation platform, CyberShake, to perform physics-based probabilistic seismic hazard analysis (PSHA) using 3D deterministic wave propagation simulations. CyberShake performs PSHA by first simulating a tensor-valued wavefield of Strain Green Tensors. CyberShake then takes an <span class="hlt">earthquake</span> rupture forecast and extends it by varying the hypocenter location and slip distribution, resulting in about 500,000 rupture variations. Seismic reciprocity is used to calculate synthetic seismograms for each rupture variation at each computation site. These seismograms are processed to obtain intensity measures, such as spectral acceleration, which are then combined with probabilities from the <span class="hlt">earthquake</span> rupture forecast to produce a hazard curve. Hazard curves are calculated at seismic frequencies up to 1 Hz for hundreds of sites in a region and the results interpolated to obtain a hazard map. In developing and verifying CyberShake, we have focused our modeling in the greater Los Angeles region. We are now expanding the hazard calculations into Central <span class="hlt">California</span>. Using workflow tools running jobs across two large-scale open-science supercomputers, NCSA Blue Waters and OLCF Titan, we calculated 1-Hz PSHA results for over 400 locations in Central <span class="hlt">California</span>. For each location, we produced hazard curves using both a 3D central <span class="hlt">California</span> velocity model created via tomographic inversion, and a regionally averaged 1D model. These new results provide low-frequency exceedance probabilities for the rapidly expanding metropolitan areas of Santa Barbara, Bakersfield, and San Luis Obispo, and lend new insights into the effects of directivity-basin coupling associated with basins juxtaposed to major faults such as the San Andreas. Particularly interesting are the basin effects associated with the deep sediments of the southern San Joaquin <span class="hlt">Valley</span>. We will compare hazard</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70176398','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70176398"><span>Prototype operational <span class="hlt">earthquake</span> prediction system</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Spall, Henry</p> <p>1986-01-01</p> <p>An objective if the U.S. <span class="hlt">Earthquake</span> Hazards Reduction Act of 1977 is to introduce into all regions of the country that are subject to large and moderate <span class="hlt">earthquakes</span>, systems for predicting <span class="hlt">earthquakes</span> and assessing <span class="hlt">earthquake</span> risk. In 1985, the USGS developed for the Secretary of the Interior a program for implementation of a prototype operational <span class="hlt">earthquake</span> prediction system in southern <span class="hlt">California</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.A11M0192F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A11M0192F"><span>Ozone Laminae and Their Entrainment Into a <span class="hlt">Valley</span> Boundary Layer, as Observed From a Mountaintop Monitoring Station, Ozonesondes, and Aircraft Over <span class="hlt">California</span>'s San Joaquin <span class="hlt">Valley</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Faloona, I. C.; Conley, S. A.; Caputi, D.; Trousdell, J.; Chiao, S.; Eiserloh, A. J., Jr.; Clark, J.; Iraci, L. T.; Yates, E. L.; Marrero, J. E.; Ryoo, J. M.; McNamara, M. E.</p> <p>2016-12-01</p> <p>The San Joaquin <span class="hlt">Valley</span> of <span class="hlt">California</span> is wide ( 75 km) and long ( 400 km), and is situated under strong atmospheric subsidence due, in part, to the proximity of the midlatitude anticyclone of the Pacific High. The capping effect of this subsidence is especially prominent during the warm season when ground level ozone is a serious air quality concern across the region. While relatively clean marine boundary layer air is primarily funneled into the <span class="hlt">valley</span> below the strong subsidence inversion at significant gaps in the upwind Coast Range mountains, airflow aloft also spills over these barriers and mixes into the <span class="hlt">valley</span> from above. Because this transmountain flow occurs under the influence of synoptic subsidence it tends to present discrete, laminar sheets of differing air composition above the <span class="hlt">valley</span> boundary layer. Meanwhile, although the boundary layers tend to remain shallow due to the prevailing subsidence, orographic and anabatic venting of <span class="hlt">valley</span> boundary layer air around the basin whips up a complex admixture of regional air masses into a "buffer layer" just above the boundary layer (zi) and below the lower free troposphere. We present scalar data of widely varying lifetimes including ozone, methane, NOx, and thermodynamic observations from upwind and within the San Joaquin <span class="hlt">Valley</span> to better explain this layering and its subsequent erosion into the <span class="hlt">valley</span> boundary layer via entrainment. Data collected at a mountaintop monitoring station on Chews Ridge in the Coast Range, by coastal ozonesondes, and aircraft are analyzed to document the dynamic layering processes around the complex terrain surrounding the <span class="hlt">valley</span>. Particular emphasis will be made on observational methods whereby distal ozone can be distinguished from the regional ozone to better understand the influence of exogenous sources on air quality in the <span class="hlt">valley</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.S33F4933W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.S33F4933W"><span>Seismo-Lineament Analysis Method (SLAM) Applied to the South Napa <span class="hlt">Earthquake</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Worrell, V. E.; Cronin, V. S.</p> <p>2014-12-01</p> <p>We used the seismo-lineament analysis method (SLAM; http://bearspace.baylor.edu/Vince_Cronin/www/SLAM/) to "predict" the location of the fault that produced the M 6.0 South Napa <span class="hlt">earthquake</span> of 24 August 2014, using hypocenter and focal mechanism data from NCEDC (http://www.ncedc.org/ncedc/catalog-search.html) and a digital elevation model from the USGS National Elevation Dataset (http://viewer.nationalmap.gov/viewer/). The ground-surface trace of the causative fault (i.e., the Browns <span class="hlt">Valley</span> strand of the West Napa fault zone; Bryant, 2000, 1982) and virtually all of the ground-rupture sites reported by the USGS and <span class="hlt">California</span> Geological Survey (http://www.eqclearinghouse.org/2014-08-24-south-napa/) were located within the north-striking seismo-lineament. We also used moment tensors published online by the USGS and GCMT (http://comcat.cr.usgs.gov/<span class="hlt">earthquakes</span>/eventpage/nc72282711#scientific_moment-tensor) as inputs to SLAM and found that their northwest-striking seismo-lineaments correlated spatially with the causative fault. We concluded that SLAM could have been used as soon as these mechanism solutions were available to help direct the search for the trace of the causative fault and possible rupture-related damage. We then considered whether the seismogenic fault could have been identified using SLAM prior to the 24 August event, based on the focal mechanisms of smaller prior <span class="hlt">earthquakes</span> reported by the NCEDC or ISC (http://www.isc.ac.uk). Seismo-lineaments from three M~3.5 events from 1990 and 2012, located in the Vallejo-Crockett area, correlate spatially with the Napa County Airport strand of the West Napa fault and extend along strike toward the Browns <span class="hlt">Valley</span> strand (Bryant, 2000, 1982). Hence, we might have used focal mechanisms from smaller <span class="hlt">earthquakes</span> to establish that the West Napa fault is likely seismogenic prior to the South Napa <span class="hlt">earthquake</span>. Early recognition that a fault with a mapped ground-surface trace is seismogenic, based on smaller <span class="hlt">earthquakes</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70027372','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70027372"><span>Structure and regional significance of the Late Permian(?) Sierra Nevada - Death <span class="hlt">Valley</span> thrust system, east-central <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Stevens, C.H.; Stone, P.</p> <p>2005-01-01</p> <p>An imbricate system of north-trending, east-directed thrust faults of late Early Permian to middle Early Triassic (most likely Late Permian) age forms a belt in east-central <span class="hlt">California</span> extending from the Mount Morrison roof pendant in the eastern Sierra Nevada to Death <span class="hlt">Valley</span>. Six major thrust faults typically with a spacing of 15-20 km, original dips probably of 25-35??, and stratigraphic throws of 2-5 km compose this structural belt, which we call the Sierra Nevada-Death <span class="hlt">Valley</span> thrust system. These thrusts presumably merge into a de??collement at depth, perhaps at the contact with crystalline basement, the position of which is unknown. We interpret the deformation that produced these thrusts to have been related to the initiation of convergent plate motion along a southeast-trending continental margin segment probably formed by Pennsylvanian transform truncation. This deformation apparently represents a period of tectonic transition to full-scale convergence and arc magmatism along the continental margin beginning in the Late Triassic in central <span class="hlt">California</span>. ?? 2005 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1261941','SCIGOV-DOEDE'); return false;" href="https://www.osti.gov/servlets/purl/1261941"><span>PoroTomo Subtask 3.2 Data files from the Distributed Acoustic Sensing experiment at Garner <span class="hlt">Valley</span>, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/dataexplorer">DOE Data Explorer</a></p> <p>Chelsea Lancelle</p> <p>2013-09-11</p> <p>In September 2013, an experiment using Distributed Acoustic Sensing (DAS) was conducted at Garner <span class="hlt">Valley</span>, a test site of the University of <span class="hlt">California</span> Santa Barbara (Lancelle et al., 2014). This submission includes all DAS data recorded during the experiment. The sampling rate for all files is 1000 samples per second. Any files with the same filename but ending in _01, _02, etc. represent sequential files from the same test. Locations of the sources are plotted on the basemap in GDR submission 481, titled: "PoroTomo Subtask 3.2 Sample data from a Distributed Acoustic Sensing experiment at Garner <span class="hlt">Valley</span>, <span class="hlt">California</span> (PoroTomo Subtask 3.2)." Lancelle, C., N. Lord, H. Wang, D. Fratta, R. Nigbor, A. Chalari, R. Karaulanov, J. Baldwin, and E. Castongia (2014), Directivity and Sensitivity of Fiber-Optic Cable Measuring Ground Motion using a Distributed Acoustic Sensing Array (abstract # NS31C-3935), AGU Fall Meeting. 
https://agu.confex.com/agu/fm1/meetingapp.cgi#Paper/19828 The e-poster is available at: https://agu.confex.com/data/handout/agu/fm14/Paper_19828_handout_696_0.pdf</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.epa.gov/publicnotices/final-approval-california-air-plan-revision-antelope-valley-air-quality-management','PESTICIDES'); return false;" href="https://www.epa.gov/publicnotices/final-approval-california-air-plan-revision-antelope-valley-air-quality-management"><span>Final Approval of <span class="hlt">California</span> Air Plan Revision; Antelope <span class="hlt">Valley</span> Air Quality Management District; VOCs From Motor Vehicle Assembly Coating Operations</span></a></p> <p><a target="_blank" href="http://www.epa.gov/pesticides/search.htm">EPA Pesticide Factsheets</a></p> <p></p> <p></p> <p>EPA is taking final action to approve a revision to the Antelope <span class="hlt">Valley</span> Air Quality Management District (AVAQMD) portion of the <span class="hlt">California</span> SIP concerning the emissions of volatile organic compounds (VOCs) from motor vehicle assembly coating operations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ngmdb.usgs.gov/Prodesc/proddesc_82885.htm','USGSPUBS'); return false;" href="http://ngmdb.usgs.gov/Prodesc/proddesc_82885.htm"><span>Logs and Scarp Data from a Paloseismic Investigation of the Surprise <span class="hlt">Valley</span> Fault Zone, Modoc County, <span class="hlt">California</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Personius, Stephen F.; Crone, Anthony J.; Machette, Michael N.; Lidke, David J.; Bradley, Lee-Ann; Mahan, Shannon</p> <p>2007-01-01</p> <p>This report contains field and laboratory data from a paleoseismic study of the Surprise <span class="hlt">Valley</span> fault zone near Cedarville, <span class="hlt">California</span>. The 85-km-long Surprise <span class="hlt">Valley</span> fault zone forms the western active margin of the Basin and Range province in northeastern <span class="hlt">California</span>. The down-to-the-east normal fault is marked by Holocene fault scarps along most of its length, from Fort Bidwell on the north to near the southern end of Surprise <span class="hlt">Valley</span>. We studied the central section of the fault to determine ages of paleoearthquakes and to better constrain late Quaternary slip rates, which we hope to compare to deformation rates derived from a recently established geodetic network in the region (Hammond and Thatcher, 2005; 2007). We excavated a trench in June 2005 across a prominent fault scarp on pluvial Lake Surprise deltaic sediments near the mouth of Cooks Canyon, 4 km north of Cedarville. This site was chosen because of the presence of a well-preserved fault scarp and its development on lacustrine deposits thought to be suitable for luminescence dating. We also logged a natural exposure of the fault in similar deltaic sediments near the mouth of Steamboat Canyon, 11 km south of Cedarville, to better understand the along-strike extent of surface ruptures. The purpose of this report is to present photomosaics, trench, drill hole, and stream exposure logs; scarp profiles; and fault slip, tephrochronologic, radiocarbon, luminescence, and unit description data obtained during this investigation. We do not attempt to use the data presented herein to construct a paleoseismic history of this part of the Surprise <span class="hlt">Valley</span> fault zone; that history will be the subject of a future report.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMED21C..03D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMED21C..03D"><span>Simulating <span class="hlt">Earthquakes</span> for Science and Society: <span class="hlt">Earthquake</span> Visualizations Ideal for use in Science Communication and Education</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de Groot, R.</p> <p>2008-12-01</p> <p>The Southern <span class="hlt">California</span> <span class="hlt">Earthquake</span> Center (SCEC) has been developing groundbreaking computer modeling capabilities for studying <span class="hlt">earthquakes</span>. These visualizations were initially shared within the scientific community but have recently gained visibility via television news coverage in Southern <span class="hlt">California</span>. Computers have opened up a whole new world for scientists working with large data sets, and students can benefit from the same opportunities (Libarkin & Brick, 2002). For example, The Great Southern <span class="hlt">California</span> ShakeOut was based on a potential magnitude 7.8 <span class="hlt">earthquake</span> on the southern San Andreas fault. The visualization created for the ShakeOut was a key scientific and communication tool for the <span class="hlt">earthquake</span> drill. This presentation will also feature SCEC Virtual Display of Objects visualization software developed by SCEC Undergraduate Studies in <span class="hlt">Earthquake</span> Information Technology interns. According to Gordin and Pea (1995), theoretically visualization should make science accessible, provide means for authentic inquiry, and lay the groundwork to understand and critique scientific issues. This presentation will discuss how the new SCEC visualizations and other <span class="hlt">earthquake</span> imagery achieve these results, how they fit within the context of major themes and study areas in science communication, and how the efficacy of these tools can be improved.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <div class="footer-extlink text-muted" style="margin-bottom:1rem; text-align:center;">Some links on this page may take you to non-federal websites. 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