Stress diffusion along the san andreas fault at parkfield, california.

Science.gov (United States)

Malin, P E; Alvarez, M G

1992-05-15

Beginning in January 1990, the epicenters of microearthquakes associated with a 12-month increase in seismicity near Parkfield, California, moved northwest to southeast along the San Andreas fault. During this sequence of events, the locally variable rate of cumulative seismic moment increased. This increase implies a local increase in fault slip. These data suggest that a southeastwardly diffusing stress front propagated along the San Andreas fault at a speed of 30 to 50 kilometers per year. Evidently, this front did not load the Parkfield asperities fast enough to produce a moderate earthquake; however, a future front might do so.

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

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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 earthquakes on the southern San Andreas Fault? The answer to this question depends on whether or not the earthquake is contained only along individual fault sections, such as the Coachella Valley 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 earthquakes must occasionally rupture a 300 km length of the San Andreas Fault from the Salton Sea to the Mojave Desert. Although many ( 65%) earthquakes along the southern San Andreas Fault likely do not rupture through the pass, our new results suggest that large >Mw 7.5 earthquakes are possible on the southern San Andreas Fault and likely

Local geomagnetic events associated with displacements on the san andreas fault.

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Breiner, S; Kovach, R L

1967-10-06

The piezomagnetic properties of rock suggest that a change in subsurface stress will manifest itself as a change in the magnetic susceptibility and remanent magnetization and hence the local geomagnetic field. A differential array of magnetometers has been operating since late 1965 on the San Andreas fault in the search for piezomagnetic signals under conditions involving active fault stress. Local changes in the geomagnetic field have been observed near Hollister, California, some tens of hours preceding the onset of abrupt creep displacement on the San Andreas fault.

Loading of the San Andreas fault by flood-induced rupture of faults beneath the Salton Sea

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Brothers, Daniel; Kilb, Debi; Luttrell, Karen; Driscoll, Neal W.; Kent, Graham

2011-01-01

The southern San Andreas fault has not experienced a large earthquake for approximately 300 years, yet the previous five earthquakes occurred at ~180-year intervals. Large strike-slip faults are often segmented by lateral stepover zones. Movement on smaller faults within a stepover zone could perturb the main fault segments and potentially trigger a large earthquake. The southern San Andreas fault terminates in an extensional stepover zone beneath the Salton Sea—a lake that has experienced periodic flooding and desiccation since the late Holocene. Here we reconstruct the magnitude and timing of fault activity beneath the Salton Sea over several earthquake cycles. We observe coincident timing between flooding events, stepover fault displacement and ruptures on the San Andreas fault. Using Coulomb stress models, we show that the combined effect of lake loading, stepover fault movement and increased pore pressure could increase stress on the southern San Andreas fault to levels sufficient to induce failure. We conclude that rupture of the stepover faults, caused by periodic flooding of the palaeo-Salton Sea and by tectonic forcing, had the potential to trigger earthquake rupture on the southern San Andreas fault. Extensional stepover zones are highly susceptible to rapid stress loading and thus the Salton Sea may be a nucleation point for large ruptures on the southern San Andreas fault.

Coulomb Stress Accumulation along the San Andreas Fault System

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Smith, Bridget; Sandwell, David

2003-01-01

Stress accumulation rates along the primary segments of the San Andreas Fault system are computed using a three-dimensional (3-D) elastic half-space model with realistic fault geometry. The model is developed in the Fourier domain by solving for the response of an elastic half-space due to a point vector body force and analytically integrating the force from a locking depth to infinite depth. This approach is then applied to the San Andreas Fault system using published slip rates along 18 major fault strands of the fault zone. GPS-derived horizontal velocity measurements spanning the entire 1700 x 200 km region are then used to solve for apparent locking depth along each primary fault segment. This simple model fits remarkably well (2.43 mm/yr RMS misfit), although some discrepancies occur in the Eastern California Shear Zone. The model also predicts vertical uplift and subsidence rates that are in agreement with independent geologic and geodetic estimates. In addition, shear and normal stresses along the major fault strands are used to compute Coulomb stress accumulation rate. As a result, we find earthquake recurrence intervals along the San Andreas Fault system to be inversely proportional to Coulomb stress accumulation rate, in agreement with typical coseismic stress drops of 1 - 10 MPa. This 3-D deformation model can ultimately be extended to include both time-dependent forcing and viscoelastic response.

Structure of the 1906 near-surface rupture zone of the San Andreas Fault, San Francisco Peninsula segment, near Woodside, California

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Rosa, C.M.; Catchings, R.D.; Rymer, M.J.; Grove, Karen; Goldman, M.R.

2016-07-08

High-resolution seismic-reflection and refraction images of the 1906 surface rupture zone of the San Andreas Fault near Woodside, California reveal evidence for one or more additional near-surface (within about 3 meters [m] depth) fault strands within about 25 m of the 1906 surface rupture. The 1906 surface rupture above the groundwater table (vadose zone) has been observed in paleoseismic trenches that coincide with our seismic profile and is seismically characterized by a discrete zone of low P-wave velocities (Vp), low S-wave velocities (Vs), high Vp/Vs ratios, and high Poisson’s ratios. A second near-surface fault strand, located about 17 m to the southwest of the 1906 surface rupture, is inferred by similar seismic anomalies. Between these two near-surface fault strands and below 5 m depth, we observed a near-vertical fault strand characterized by a zone of high Vp, low Vs, high Vp/Vs ratios, and high Poisson’s ratios on refraction tomography images and near-vertical diffractions on seismic-reflection images. This prominent subsurface zone of seismic anomalies is laterally offset from the 1906 surface rupture by about 8 m and likely represents the active main (long-term) strand of the San Andreas Fault at 5 to 10 m depth. Geometries of the near-surface and subsurface (about 5 to 10 m depth) fault zone suggest that the 1906 surface rupture dips southwestward to join the main strand of the San Andreas Fault at about 5 to 10 m below the surface. The 1906 surface rupture forms a prominent groundwater barrier in the upper 3 to 5 m, but our interpreted secondary near-surface fault strand to the southwest forms a weaker barrier, suggesting that there has been less or less-recent near-surface slip on that strand. At about 6 m depth, the main strand of the San Andreas Fault consists of water-saturated blue clay (collected from a hand-augered borehole), which is similar to deeply weathered serpentinite observed within the main strand of the San Andreas Fault at

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

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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

Correlation of clayey gouge in a surface exposure of serpentinite in the San Andreas Fault with gouge from the San Andreas Fault Observatory at Depth (SAFOD)

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Moore, Diane E.; Rymer, Michael J.

2012-05-01

Magnesium-rich clayey gouge similar to that comprising the two actively creeping strands of the San Andreas Fault in drill core from the San Andreas Fault Observatory at Depth (SAFOD) has been identified in a nearby outcrop of serpentinite within the fault zone at Nelson Creek. Each occurrence of the gouge consists of porphyroclasts of serpentinite and sedimentary rocks dispersed in a fine-grained, foliated matrix of Mg-rich smectitic clays. The clay minerals in all three gouges are interpreted to be the product of fluid-assisted, shear-enhanced reactions between quartzofeldspathic wall rocks and serpentinite that was tectonically entrained in the fault from a source in the Coast Range Ophiolite. We infer that the gouge at Nelson Creek connects to one or both of the gouge zones in the SAFOD core, and that similar gouge may occur at depths in between. The special significance of the outcrop is that it preserves the early stages of mineral reactions that are greatly advanced at depth, and it confirms the involvement of serpentinite and the Mg-rich phyllosilicate minerals that replace it in promoting creep along the central San Andreas Fault.

Migrating tremors illuminate complex deformation beneath the seismogenic San Andreas fault.

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Shelly, David R

2010-02-04

The San Andreas fault is one of the most extensively studied faults in the world, yet its physical character and deformation mode beneath the relatively shallow earthquake-generating portion remain largely unconstrained. Tectonic 'non-volcanic' tremor, a recently discovered seismic signal probably generated by shear slip on the deep extension of some major faults, can provide new insight into the deep fate of such faults, including that of the San Andreas fault near Parkfield, California. Here I examine continuous seismic data from mid-2001 to 2008, identifying tremor and decomposing the signal into different families of activity based on the shape and timing of the waveforms at multiple stations. This approach allows differentiation between activities from nearby patches of the deep fault and begins to unveil rich and complex patterns of tremor occurrence. I find that tremor exhibits nearly continuous migration, with the most extensive episodes propagating more than 20 kilometres along fault strike at rates of 15-80 kilometres per hour. This suggests that the San Andreas fault remains a localized through-going structure, at least to the base of the crust, in this area. Tremor rates and recurrence behaviour changed markedly in the wake of the 2004 magnitude-6.0 Parkfield earthquake, but these changes were far from uniform within the tremor zone, probably reflecting heterogeneous fault properties and static and dynamic stresses decaying away from the rupture. The systematic recurrence of tremor demonstrated here suggests the potential to monitor detailed time-varying deformation on this portion of the deep San Andreas fault, deformation which unsteadily loads the shallower zone that last ruptured in the 1857 magnitude-7.9 Fort Tejon earthquake.

Synthetic seismicity for the San Andreas fault

Directory of Open Access Journals (Sweden)

S. N. Ward

1994-06-01

Full Text Available Because historical catalogs generally span only a few repetition intervals of major earthquakes, they do not provide much constraint on how regularly earthquakes recur. In order to obtain better recurrence statistics and long-term probability estimates for events M ? 6 on the San Andreas fault, we apply a seismicity model to this fault. The model is based on the concept of fault segmentation and the physics of static dislocations which allow for stress transfer between segments. Constraints are provided by geological and seismological observations of segment lengths, characteristic magnitudes and long-term slip rates. Segment parameters slightly modified from the Working Group on California Earthquake Probabilities allow us to reproduce observed seismicity over four orders of magnitude. The model yields quite irregular earthquake recurrence patterns. Only the largest events (M ? 7.5 are quasi-periodic; small events cluster. Both the average recurrence time and the aperiodicity are also a function of position along the fault. The model results are consistent with paleoseismic data for the San Andreas fault as well as a global set of historical and paleoseismic recurrence data. Thus irregular earthquake recurrence resulting from segment interaction is consistent with a large range of observations.

Conductivity Structure of the San Andreas Fault, Parkfield, Revisited

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Park, S. K.; Roberts, J. J.

2003-12-01

Laboratory measurements of samples of sedimentary rocks from the Parkfield syncline reveal resistivities as low as 1 ohm m when saturated with fluids comparable to those found in nearby wells. The syncline lies on the North American side of the San Andreas fault at Parkfield and plunges northwestward into the fault zone. A previous interpretation of a high resolution magnetotelluric profile across the San Andreas fault at Parkfield identified an anomalously conductive (1-3 ohm m) region just west of the fault and extending to depths of 3 km. These low resistivity rocks were inferred to be crushed rock in the fault zone that was saturated with brines. As an alternative to this interpretation, we suggest that this anomalous region is actually the Parkfield syncline and that the current trace of the San Andreas fault at Middle Mountain does not form the boundary between the Salinian block and the North American plate. Instead, that boundary is approximately 1 km west and collocated with current seismicity. This work was performed under the auspices of the U.S. Department of Energy by the University of California Lawrence Livermore National Laboratory under contract W-7405-ENG-48 and supported specifically by the Office of Basic Energy Science. Additional support was provided by the U.S. Geological Survey (USGS), Department of the Interior, under USGS Award number 03HQGR0041. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government.

Impact of a Large San Andreas Fault Earthquake on Tall Buildings in Southern California

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Krishnan, S.; Ji, C.; Komatitsch, D.; Tromp, J.

2004-12-01

In 1857, an earthquake 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 earthquake 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 California. In order to study the effects of large San Andreas fault earthquakes on tall buildings in Southern California, we use the finite source of the magnitude 7.9 2001 Denali fault earthquake 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 earthquake 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 California 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 earthquake 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

The Eastern California Shear Zone as the northward extension of the southern San Andreas Fault

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Thatcher, Wayne R.; Savage, James C.; Simpson, Robert W.

2016-01-01

Cluster analysis offers an agnostic way to organize and explore features of the current GPS velocity field without reference to geologic information or physical models using information only contained in the velocity field itself. We have used cluster analysis of the Southern California Global Positioning System (GPS) velocity field to determine the partitioning of Pacific-North America relative motion onto major regional faults. Our results indicate the large-scale kinematics of the region is best described with two boundaries of high velocity gradient, one centered on the Coachella section of the San Andreas Fault and the Eastern California Shear Zone and the other defined by the San Jacinto Fault south of Cajon Pass and the San Andreas Fault farther north. The ~120 km long strand of the San Andreas between Cajon Pass and Coachella Valley (often termed the San Bernardino and San Gorgonio sections) is thus currently of secondary importance and carries lesser amounts of slip over most or all of its length. We show these first order results are present in maps of the smoothed GPS velocity field itself. They are also generally consistent with currently available, loosely bounded geologic and geodetic fault slip rate estimates that alone do not provide useful constraints on the large-scale partitioning we show here. Our analysis does not preclude the existence of smaller blocks and more block boundaries in Southern California. However, attempts to identify smaller blocks along and adjacent to the San Gorgonio section were not successful.

Constraints on the stress state of the San Andreas Fault with analysis based on core and cuttings from San Andreas Fault Observatory at Depth (SAFOD) drilling phases 1 and 2

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Tembe, S.; Lockner, D.; Wong, T.-F.

2009-01-01

Analysis of field data has led different investigators to conclude that the San Andreas Fault (SAF) has either anomalously low frictional sliding strength (?? 0.6). Arguments for the apparent weakness of the SAF generally hinge on conceptual models involving intrinsically weak gouge or elevated pore pressure within the fault zone. Some models assert that weak gouge and/or high pore pressure exist under static conditions while others consider strength loss or fluid pressure increase due to rapid coseismic fault slip. The present paper is composed of three parts. First, we develop generalized equations, based on and consistent with the Rice (1992) fault zone model to relate stress orientation and magnitude to depth-dependent coefficient of friction and pore pressure. Second, we present temperature-and pressure-dependent friction measurements from wet illite-rich fault gouge extracted from San Andreas Fault Observatory at Depth (SAFOD) phase 1 core samples and from weak minerals associated with the San Andreas Fault. Third, we reevaluate the state of stress on the San Andreas Fault in light of new constraints imposed by SAFOD borehole data. Pure talc (?????0.1) had the lowest strength considered and was sufficiently weak to satisfy weak fault heat flow and stress orientation constraints with hydrostatic pore pressure. Other fault gouges showed a systematic increase in strength with increasing temperature and pressure. In this case, heat flow and stress orientation constraints would require elevated pore pressure and, in some cases, fault zone pore pressure in excess of vertical stress. Copyright 2009 by the American Geophysical Union.

Chemical and Physical Characteristics of Pulverized Granitic Rock Adjacent to the San Andreas, Garlock and San Jacinto Faults: Implications for Earthquake Physics

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Rockwell, T. K.; Sisk, M.; Stillings, M.; Girty, G.; Dor, O.; Wechsler, N.; Ben-Zion, Y.

2008-12-01

We present new detailed analyses of pulverized granitic rocks from sections adjacent to the San Andreas, Garlock and San Jacinto faults in southern California. Along the San Andreas and Garlock faults, the Tejon Lookout Granite is pulverized in all exposures within about 100 m of both faults. Along the Clark strand of the San Jacinto fault in Horse Canyon, the pulverization of granitic rocks is highly asymmetric, with a much broader zone of pulverization along the southwest side of the Clark fault. In areas where the granite is injected as dyke rock into schist, only the granitic rock shows pulverization, demonstrating the control of rock type on the pulverization process. Chemical analyses indicate little or no weathering in the bulk of the rock, although XRD analysis shows the presence of smectite, illite, and minor kaolinite in the clay-sized fraction. Weathering products may dominate in the less than 1 micron fraction. The average grain size in all samples of pulverized granitic rock range between about 20 and 200 microns (silt to fine sand), with the size distribution in part a function of proximity to the primary slip zone. The San Andreas fault samples are generally finer than those collected from along the Garlock or San Jacinto faults. The particle size distribution for all samples is non-fractal, with a distinct slope break in the 60-100 micron range, which suggests that pulverization is not a consequence of direct shear. This average particle size is quite coarser than previous reports, which we attribute to possible measurement errors in the prior work. Our data and observations suggest that dynamic fracturing in the wall rock of these three major faults only accounts for 1% or less of the earthquake energy budget.

A simulation of the San Andreas fault experiment

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Agreen, R. W.; Smith, D. E.

1974-01-01

The San Andreas fault experiment (Safe), which employs two laser tracking systems for measuring the relative motion of two points on opposite sides of the fault, has been simulated for an 8-yr observation period. The two tracking stations are located near San Diego on the western side of the fault and near Quincy on the eastern side; they are roughly 900 km apart. Both will simultaneously track laser reflector equipped satellites as they pass near the stations. Tracking of the Beacon Explorer C spacecraft has been simulated for these two stations during August and September for 8 consecutive years. An error analysis of the recovery of the relative location of Quincy from the data has been made, allowing for model errors in the mass of the earth, the gravity field, solar radiation pressure, atmospheric drag, errors in the position of the San Diego site, and biases and noise in the laser systems. The results of this simulation indicate that the distance of Quincy from San Diego will be determined each year with a precision of about 10 cm. Projected improvements in these model parameters and in the laser systems over the next few years will bring the precision to about 1-2 cm by 1980.

A critical evaluation of crustal dehydration as the cause of an overpressured and weak San Andreas Fault

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Fulton, P.M.; Saffer, D.M.; Bekins, B.A.

2009-01-01

Many plate boundary faults, including the San Andreas Fault, appear to slip at unexpectedly low shear stress. One long-standing explanation for a "weak" San Andreas Fault is that fluid release by dehydration reactions during regional metamorphism generates elevated fluid pressures that are localized within the fault, reducing the effective normal stress. We evaluate this hypothesis by calculating realistic fluid production rates for the San Andreas Fault system, and incorporating them into 2-D fluid flow models. Our results show that for a wide range of permeability distributions, fluid sources from crustal dehydration are too small and short-lived to generate, sustain, or localize fluid pressures in the fault sufficient to explain its apparent mechanical weakness. This suggests that alternative mechanisms, possibly acting locally within the fault zone, such as shear compaction or thermal pressurization, may be necessary to explain a weak San Andreas Fault. More generally, our results demonstrate the difficulty of localizing large fluid pressures generated by regional processes within near-vertical fault zones. ?? 2009 Elsevier B.V.

San Andreas Fault in the Carrizo Plain

Science.gov (United States)

2000-01-01

The 1,200-kilometer (800-mile)San Andreas is the longest fault in California and one of the longest in North America. This perspective view of a portion of the fault was generated using data from the Shuttle Radar Topography Mission (SRTM), which flew on NASA's Space Shuttle last February, and an enhanced, true-color Landsat satellite image. The view shown looks southeast along the San Andreas where it cuts along the base of the mountains in the Temblor Range near Bakersfield. The fault is the distinctively linear feature to the right of the mountains. To the left of the range is a portion of the agriculturally rich San Joaquin Valley. In the background is the snow-capped peak of Mt. Pinos at an elevation of 2,692 meters (8,831 feet). The complex topography in the area is some of the most spectacular along the course of the fault. To the right of the fault is the famous Carrizo Plain. Dry conditions on the plain have helped preserve the surface trace of the fault, which is scrutinized by both amateur and professional geologists. In 1857, one of the largest earthquakes ever recorded in the United States occurred just north of the Carrizo Plain. With an estimated magnitude of 8.0, the quake severely shook buildings in Los Angeles, caused significant surface rupture along a 350-kilometer (220-mile) segment of the fault, and was felt as far away as Las Vegas, Nev. This portion of the San Andreas is an important area of study for seismologists. For visualization purposes, topographic heights displayed in this image are exaggerated two times.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

Stress near geometrically complex strike-slip faults - Application to the San Andreas fault at Cajon Pass, southern California

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Saucier, Francois; Humphreys, Eugene; Weldon, Ray, II

1992-01-01

A model is presented to rationalize the state of stress near a geometrically complex major strike-slip fault. Slip on such a fault creates residual stresses that, with the occurrence of several slip events, can dominate the stress field near the fault. The model is applied to the San Andreas fault near Cajon Pass. The results are consistent with the geological features, seismicity, the existence of left-lateral stress on the Cleghorn fault, and the in situ stress orientation in the scientific well, found to be sinistral when resolved on a plane parallel to the San Andreas fault. It is suggested that the creation of residual stresses caused by slip on a wiggle San Andreas fault is the dominating process there.

Expression of San Andreas fault on Seasat radar image

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Sabins, F. F., Jr.; Blom, R.; Elachi, C.

1980-01-01

A Seasat image (23.5 cm wavelength) of the Durmid Hills in southern California, the San Andreas Fault was analyzed. It is shown that a prominent southeast trending tonal lineament exists that is bright on the southwest side and dark on the northeast side. The cause of the contrasting signatures on opposite sides of the lineament was determined and the geologic signficance of the lineament was evaluated.

Scientific drilling into the San Andreas Fault Zone - an overview of SAFOD's first five years

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Zoback, Mark; Hickman, Stephen; Ellsworth, William; ,

2011-01-01

The San Andreas Fault Observatory at Depth (SAFOD) was drilled to study the physical and chemical processes controlling faulting and earthquake generation along an active, plate-bounding fault at depth. SAFOD is located near Parkfield, California and penetrates a section of the fault that is moving due to a combination of repeating microearthquakes and fault creep. Geophysical logs define the San Andreas Fault Zone to be relatively broad (~200 m), containing several discrete zones only 2–3 m wide that exhibit very low P- and S-wave velocities and low resistivity. Two of these zones have progressively deformed the cemented casing at measured depths of 3192 m and 3302 m. Cores from both deforming zones contain a pervasively sheared, cohesionless, foliated fault gouge that coincides with casing deformation and explains the observed extremely low seismic velocities and resistivity. These cores are being now extensively tested in laboratories around the world, and their composition, deformation mechanisms, physical properties, and rheological behavior are studied. Downhole measurements show that within 200 m (maximum) of the active fault trace, the direction of maximum horizontal stress remains at a high angle to the San Andreas Fault, consistent with other measurements. The results from the SAFOD Main Hole, together with the stress state determined in the Pilot Hole, are consistent with a strong crust/weak fault model of the San Andreas. Seismic instrumentation has been deployed to study physics of faulting—earthquake nucleation, propagation, and arrest—in order to test how laboratory-derived concepts scale up to earthquakes occurring in nature.

Data Files for Ground-Motion Simulations of the 1906 San Francisco Earthquake and Scenario Earthquakes on the Northern San Andreas Fault

Science.gov (United States)

Aagaard, Brad T.; Barall, Michael; Brocher, Thomas M.; Dolenc, David; Dreger, Douglas; Graves, Robert W.; Harmsen, Stephen; Hartzell, Stephen; Larsen, Shawn; McCandless, Kathleen; Nilsson, Stefan; Petersson, N. Anders; Rodgers, Arthur; Sjogreen, Bjorn; Zoback, Mary Lou

2009-01-01

This data set contains results from ground-motion simulations of the 1906 San Francisco earthquake, seven hypothetical earthquakes on the northern San Andreas Fault, and the 1989 Loma Prieta earthquake. The bulk of the data consists of synthetic velocity time-histories. Peak ground velocity on a 1/60th degree grid and geodetic displacements from the simulations are also included. Details of the ground-motion simulations and analysis of the results are discussed in Aagaard and others (2008a,b).

Strain on the san andreas fault near palmdale, california: rapid, aseismic change.

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Savage, J C; Prescott, W H; Lisowski, M; King, N E

1981-01-02

Frequently repeated strain measurements near Palmdale, California, during the period from 1971 through 1980 indicate that, in addition to a uniform accumulation of right-lateral shear strain (engineering shear, 0.35 microradian per year) across the San Andreas fault, a 1-microstrain contraction perpendicular to the fault that accumulated gradually during the interval 1974 through 1978 was aseismically released between February and November 1979. Subsequently (November 1979 to March 1980), about half of the contraction was recovered. This sequence of strain changes can be explained in terms of south-southwestward migration of a slip event consisting of the south-southwestward movement of the upper crust on a horizontal detachment surface at a depth of 10 to 30 kilometers. The large strain change in 1979 corresponds to the passage of the slip event beneath the San Andreas fault.

Nonvolcanic tremors deep beneath the San Andreas Fault.

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Nadeau, Robert M; Dolenc, David

2005-01-21

We have discovered nonvolcanic tremor activity (i.e., long-duration seismic signals with no clear P or S waves) within a transform plate boundary zone along the San Andreas Fault near Cholame, California, the inferred epicentral region of the 1857 Fort Tejon earthquake (moment magnitude approximately 7.8). The tremors occur between 20 to 40 kilometers' depth, below the seismogenic zone (the upper approximately 15 kilometers of Earth's crust where earthquakes occur), and their activity rates may correlate with variations in local earthquake activity.

Neotectonics of the San Andreas Fault system, basin and range province juncture

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Estes, J. E.; Crowell, J. C.

1982-01-01

The development, active processes, and tectonic interplay of the southern San Andreas fault system and the basin and range province were studied. The study consist of data acquisition and evaluation, technique development, and image interpretation and mapping. Potentially significant geologic findings are discussed.

Perspective View, San Andreas Fault

Science.gov (United States)

2000-01-01

The prominent linear feature straight down the center of this perspective view is California's famous San Andreas Fault. The image, created with data from NASA's Shuttle Radar Topography Mission (SRTM), will be used by geologists studying fault dynamics and landforms resulting from active tectonics. This segment of the fault lies west of the city of Palmdale, Calif., about 100 kilometers (about 60 miles) northwest of Los Angeles. The fault is the active tectonic boundary between the North American plate on the right, and the Pacific plate on the left. Relative to each other, the Pacific plate is moving away from the viewer and the North American plate is moving toward the viewer along what geologists call a right lateral strike-slip fault. Two large mountain ranges are visible, the San Gabriel Mountains on the left and the Tehachapi Mountains in the upper right. Another fault, the Garlock Fault lies at the base of the Tehachapis; the San Andreas and the Garlock Faults meet in the center distance near the town of Gorman. In the distance, over the Tehachapi Mountains is California's Central Valley. Along the foothills in the right hand part of the image is the Antelope Valley, including the Antelope Valley California Poppy Reserve. The data used to create this image were acquired by SRTM aboard the Space Shuttle Endeavour, launched on February 11, 2000.This type of display adds the important dimension of elevation to the study of land use and environmental processes as observed in satellite images. The perspective view was created by draping a Landsat satellite image over an SRTM elevation model. Topography is exaggerated 1.5 times vertically. The Landsat image was provided by the United States Geological Survey's Earth Resources Observations Systems (EROS) Data Center, Sioux Falls, South Dakota.SRTM uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour

Correlation of data on strain accumulation adjacent to the San Andreas Fault with available models

Science.gov (United States)

Turcotte, Donald L.

1986-01-01

Theoretical and numerical studies of deformation on strike slip faults were performed and the results applied to geodetic observations performed in the vicinity of the San Andreas Fault in California. The initial efforts were devoted to an extensive series of finite element calculations of the deformation associated with cyclic displacements on a strike-slip fault. Measurements of strain accumulation adjacent to the San Andreas Fault indicate that the zone of strain accumulation extends only a few tens of kilometers away from the fault. There is a concern about the tendency to make geodetic observations along the line to the source. This technique has serious problems for strike slip faults since the vector velocity is also along the fault. Use of a series of stations lying perpendicular to the fault whose positions are measured relative to a reference station are suggested to correct the problem. The complexity of faulting adjacent to the San Andreas Fault indicated that the homogeneous elastic and viscoelastic approach to deformation had serious limitations. These limitation led to the proposal of an approach that assumes a fault is composed of a distribution of asperities and barriers on all scales. Thus, an earthquake on a fault is treated as a failure of a fractal tree. Work continued on the development of a fractal based model for deformation in the western United States. In order to better understand the distribution of seismicity on the San Andreas Fault system a fractal analog was developed. The fractal concept also provides a means of testing whether clustering in time or space is a scale-invariant process.

Resurvey of site stability quadrilaterals, Otay Mountain and Quincy, California. [San Andreas fault experiment

Science.gov (United States)

Scholz, C. H.

1977-01-01

Trilateration quadrilaterals established across two faults near the San Andreas Fault Experiment laser/satellite ranging sites were resurveyed after four years. No evidence of significant tectonic motion was found.

Evaluation of hypotheses for right-lateral displacement of Neogene strata along the San Andreas Fault between Parkfield and Maricopa, California

Science.gov (United States)

Stanley, Richard G.; Barron, John A.; Powell, Charles L.

2017-12-22

We used geological field studies and diatom biostratigraphy to test a published hypothesis that Neogene marine siliceous strata in the Maricopa and Parkfield areas, located on opposite sides of the San Andreas Fault, were formerly contiguous and then were displaced by about 80–130 kilometers (km) of right-lateral slip along the fault. In the Maricopa area on the northeast side of the San Andreas Fault, the upper Miocene Bitterwater Creek Shale consists of hard, siliceous shale with dolomitic concretions and turbidite sandstone interbeds. Diatom assemblages indicate that the Bitterwater Creek Shale was deposited about 8.0–6.7 million years before present (Ma) at the same time as the uppermost part of the Monterey Formation in parts of coastal California. In the Parkfield area on the southwest side of the San Andreas Fault, the upper Miocene Pancho Rico Formation consists of soft to indurated mudstone and siltstone and fossiliferous, bioturbated sandstone. Diatom assemblages from the Pancho Rico indicate deposition about 6.7–5.7 Ma (latest Miocene), younger than the Bitterwater Creek Shale and at about the same time as parts of the Sisquoc Formation and Purisima Formation in coastal California. Our results show that the Bitterwater Creek Shale and Pancho Rico Formation are lithologically unlike and of different ages and therefore do not constitute a cross-fault tie that can be used to estimate rightlateral displacement along the San Andreas Fault.In the Maricopa area northeast of the San Andreas Fault, the Bitterwater Creek Shale overlies conglomeratic fan-delta deposits of the upper Miocene Santa Margarita Formation, which in turn overlie siliceous shale of the Miocene Monterey Formation from which we obtained a diatom assemblage dated at about 10.0–9.3 Ma. Previous investigations noted that the Santa Margarita Formation in the Maricopa area contains granitic and metamorphic clasts derived from sources in the northern Gabilan Range, on the opposite side of

Habitat information in the region on the underwater San Andreas Fault - Topic: Exploring the Undersea San Andreas Fault: Revealing the Past, Present, and Future at the Centennial of the Great 1906 Earthquake

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — During this exploration, the first comprehensive high-resolution multi-beam sonar and seismic reflection survey of the Northern San Andreas Fault (NSAF) was...

Monitoring microearthquakes with the San Andreas fault observatory at depth

Science.gov (United States)

Oye, V.; Ellsworth, W.L.

2007-01-01

In 2005, the San Andreas Fault Observatory at Depth (SAFOD) was drilled through the San Andreas Fault zone at a depth of about 3.1 km. The borehole has subsequently been instrumented with high-frequency geophones in order to better constrain locations and source processes of nearby microearthquakes that will be targeted in the upcoming phase of SAFOD. The microseismic monitoring software MIMO, developed by NORSAR, has been installed at SAFOD to provide near-real time locations and magnitude estimates using the high sampling rate (4000 Hz) waveform data. To improve the detection and location accuracy, we incorporate data from the nearby, shallow borehole (???250 m) seismometers of the High Resolution Seismic Network (HRSN). The event association algorithm of the MIMO software incorporates HRSN detections provided by the USGS real time earthworm software. The concept of the new event association is based on the generalized beam forming, primarily used in array seismology. The method requires the pre-computation of theoretical travel times in a 3D grid of potential microearthquake locations to the seismometers of the current station network. By minimizing the differences between theoretical and observed detection times an event is associated and the location accuracy is significantly improved.

Scientific Drilling Into the San Andreas Fault Zone —An Overview of SAFOD’s First Five Years

Directory of Open Access Journals (Sweden)

Stephen Hickman

2011-03-01

Full Text Available The San Andreas Fault Observatory at Depth (SAFODwas drilled to study the physical and chemical processes controlling faulting and earthquake generation along an active, plate-bounding fault at depth. SAFOD is located near Parkfield, California and penetrates a section of the fault that is moving due to a combination of repeating microearthquakes and fault creep. Geophysical logs define the SanAndreas Fault Zone to be relatively broad (~200 m, containing several discrete zones only 2–3 m wide that exhibit very low P- and S-wave velocities and low resistivity. Two of these zones have progressively deformed the cemented casing at measured depths of 3192 m and 3302 m. Cores from both deforming zones contain a pervasively sheared, cohesionless, foliated fault gouge that coincides with casing deformation and explains the observed extremely low seismic velocities and resistivity. These cores are being now extensivelytested in laboratories around the world, and their composition, deformation mechanisms, physical properties, and rheological behavior are studied. Downhole measurements show that within 200 m (maximum of the active fault trace, the direction of maximum horizontal stress remains at a high angle to the San Andreas Fault, consistent with other measurements. The results from the SAFOD Main Hole, together with the stress state determined in the Pilot Hole, are consistent with a strong crust/weak fault model of the San Andreas. Seismic instrumentation has been deployed to study physics of faulting—earthquake nucleation, propagation, and arrest—in order to test how laboratory-derived concepts scale up to earthquakes occurring in nature.

Slip in the 1857 and earlier large earthquakes along the Carrizo Plain, San Andreas Fault.

Science.gov (United States)

Zielke, Olaf; Arrowsmith, J Ramón; Grant Ludwig, Lisa; Akçiz, Sinan O

2010-02-26

The moment magnitude (Mw) 7.9 Fort Tejon earthquake of 1857, with a approximately 350-kilometer-long surface rupture, was the most recent major earthquake along the south-central San Andreas Fault, California. Based on previous measurements of its surface slip distribution, rupture along the approximately 60-kilometer-long Carrizo segment was thought to control the recurrence of 1857-like earthquakes. New high-resolution topographic data show that the average slip along the Carrizo segment during the 1857 event was 5.3 +/- 1.4 meters, eliminating the core assumption for a linkage between Carrizo segment rupture and recurrence of major earthquakes along the south-central San Andreas Fault. Earthquake slip along the Carrizo segment may recur in earthquake clusters with cumulative slip of approximately 5 meters.

Climate-modulated channel incision and rupture history of the San Andreas Fault in the Carrizo Plain.

Science.gov (United States)

Grant Ludwig, Lisa; Akçiz, Sinan O; Noriega, Gabriela R; Zielke, Olaf; Arrowsmith, J Ramón

2010-02-26

The spatial and temporal distribution of fault slip is a critical parameter in earthquake source models. Previous geomorphic and geologic studies of channel offset along the Carrizo section of the south central San Andreas Fault assumed that channels form more frequently than earthquakes occur and suggested that repeated large-slip earthquakes similar to the 1857 Fort Tejon earthquake illustrate typical fault behavior. We found that offset channels in the Carrizo Plain incised less frequently than they were offset by earthquakes. Channels have been offset by successive earthquakes with variable slip since ~1400. This nonuniform slip history reveals a more complex rupture history than previously assumed for the structurally simplest section of the San Andreas Fault.

Geophysical Characterization of Groundwater-Fault Dynamics at San Andreas Oasis

Science.gov (United States)

Faherty, D.; Polet, J.; Osborn, S. G.

2017-12-01

The San Andreas Oasis has historically provided a reliable source of fresh water near the northeast margin of the Salton Sea, although since the recent completion of the Coachella Canal Lining Project and persistent drought in California, surface water at the site has begun to disappear. This may be an effect of the canal lining, however, the controls on groundwater are complicated by the presence of the Hidden Springs Fault (HSF), a northeast dipping normal fault that trends near the San Andreas Oasis. Its surface expression is apparent as a lineation against which all plant growth terminates, suggesting that it may form a partial barrier to subsurface groundwater flow. Numerous environmental studies have detailed the chemical evolution of waters resources at San Andreas Spring, although there remains a knowledge gap on the HSF and its relation to groundwater at the site. To better constrain flow paths and characterize groundwater-fault interactions, we have employed resistivity surveys near the surface trace of the HSF to generate profiles of lateral and depth-dependent variations in resistivity. The survey design is comprised of lines installed in Wenner Arrays, using an IRIS Syscal Kid, with 24 electrodes, at a maximum electrode spacing of 5 meters. In addition, we have gathered constraints on the geometry of the HSF using a combination of ground-based magnetic and gravity profiles, conducted with a GEM walking Proton Precession magnetometer and a Lacoste & Romberg gravimeter. Seventeen gravity measurements were acquired across the surface trace of the fault. Preliminary resistivity results depict a shallow conductor localized at the oasis and discontinuous across the HSF. Magnetic data reveal a large contrast in subsurface magnetic susceptibility that appears coincident with the surface trace and trend of the HSF, while gravity data suggests a shallow, relatively high density anomaly centered near the oasis. These data also hint at a second, previously

Re-evaluating fault zone evolution, geometry, and slip rate along the restraining bend of the southern San Andreas Fault Zone

Science.gov (United States)

Blisniuk, K.; Fosdick, J. C.; Balco, G.; Stone, J. O.

2017-12-01

This study presents new multi-proxy data to provide an alternative interpretation of the late -to-mid Quaternary evolution, geometry, and slip rate of the southern San Andreas fault zone, comprising of the Garnet Hill, Banning, and Mission Creek fault strands, along its restraining bend near the San Bernardino Mountains and San Gorgonio Pass. Present geologic and geomorphic studies in the region indicate that as the Mission Creek and Banning faults diverge from one another in the southern Indio Hills, the Banning Fault Strand accommodates the majority of lateral displacement across the San Andreas Fault Zone. In this currently favored kinematic model of the southern San Andreas Fault Zone, slip along the Mission Creek Fault Strand decreases significantly northwestward toward the San Gorgonio Pass. Along this restraining bend, the Mission Creek Fault Strand is considered to be inactive since the late -to-mid Quaternary ( 500-150 kya) due to the transfer of plate boundary strain westward to the Banning and Garnet Hills Fault Strands, the Jacinto Fault Zone, and northeastward, to the Eastern California Shear Zone. Here, we present a revised geomorphic interpretation of fault displacement, initial 36Cl/10Be burial ages, sediment provenance data, and detrital geochronology from modern catchments and displaced Quaternary deposits that improve across-fault correlations. We hypothesize that continuous large-scale translation of this structure has occurred throughout its history into the present. Accordingly, the Mission Creek Fault Strand is active and likely a primary plate boundary fault at this latitude.

1855 and 1991 Surveys of the San Andreas Fault: Implications for Fault Machanics

Science.gov (United States)

Grant, Lisa B.; Donnellan, Andrea

1993-01-01

Two monuments from an 1855 survey that spans the San Andreas fault in the Carrizo Plain have been displaced 11.0+/-2.5m right-laterally by the 1857 Fort Tejon earthquake and associated seismicity and afterslip by the 1857 Fort Tejon earthquake and associated seismicity and afterslip.

Evolution of the northern santa cruz mountains by advection of crust past a san andreas fault bend.

Science.gov (United States)

Anderson, R S

1990-07-27

The late Quaternary marine terraces near Santa Cruz, California, reflect uplift associated with the nearby restraining bend on the San Andreas fault. Excellent correspondence of the coseismic vertical displacement field caused by the 17 October 1989 magnitude 7.1 Loma Prieta earthquake and the present elevations of these terraces allows calculation of maximum long-term uplift rates 1 to 2 kilometers west of the San Andreas fault of 0.8 millimeters per year. Over several million years, this uplift, in concert with the right lateral translation of the resulting topography, and with continual attack by geomorphic processes, can account for the general topography of the northern Santa Cruz Mountains.

Correlation between deep fluids, tremor and creep along the central San Andreas fault.

Science.gov (United States)

Becken, Michael; Ritter, Oliver; Bedrosian, Paul A; Weckmann, Ute

2011-11-30

The seismicity pattern along the San Andreas fault near Parkfield and Cholame, California, varies distinctly over a length of only fifty kilometres. Within the brittle crust, the presence of frictionally weak minerals, fault-weakening high fluid pressures and chemical weakening are considered possible causes of an anomalously weak fault northwest of Parkfield. Non-volcanic tremor from lower-crustal and upper-mantle depths is most pronounced about thirty kilometres southeast of Parkfield and is thought to be associated with high pore-fluid pressures at depth. Here we present geophysical evidence of fluids migrating into the creeping section of the San Andreas fault that seem to originate in the region of the uppermost mantle that also stimulates tremor, and evidence that along-strike variations in tremor activity and amplitude are related to strength variations in the lower crust and upper mantle. Interconnected fluids can explain a deep zone of anomalously low electrical resistivity that has been imaged by magnetotelluric data southwest of the Parkfield-Cholame segment. Near Cholame, where fluids seem to be trapped below a high-resistivity cap, tremor concentrates adjacent to the inferred fluids within a mechanically strong zone of high resistivity. By contrast, subvertical zones of low resistivity breach the entire crust near the drill hole of the San Andreas Fault Observatory at Depth, northwest of Parkfield, and imply pathways for deep fluids into the eastern fault block, coincident with a mechanically weak crust and the lower tremor amplitudes in the lower crust. Fluid influx to the fault system is consistent with hypotheses of fault-weakening high fluid pressures in the brittle crust.

A nonlinear least-squares inverse analysis of strike-slip faulting with application to the San Andreas fault

Science.gov (United States)

Williams, Charles A.; Richardson, Randall M.

1988-01-01

A nonlinear weighted least-squares analysis was performed for a synthetic elastic layer over a viscoelastic half-space model of strike-slip faulting. Also, an inversion of strain rate data was attempted for the locked portions of the San Andreas fault in California. Based on an eigenvector analysis of synthetic data, it is found that the only parameter which can be resolved is the average shear modulus of the elastic layer and viscoelastic half-space. The other parameters were obtained by performing a suite of inversions for the fault. The inversions on data from the northern San Andreas resulted in predicted parameter ranges similar to those produced by inversions on data from the whole fault.

Electrical resistivity variations associated with earthquakes on the san andreas fault.

Science.gov (United States)

Mazzella, A; Morrison, H F

1974-09-06

A 24 percent precursory change in apparent electrical resistivity was observed before a magnitude 3.9 earthquake of strike-slip nature on the San Andreas fault in central California. The experimental configuration and numerical calculations suggest that the change is associated with a volume at depth rather than some near-surface phenomenon. The character and duration of the precursor period agree well with those of other earthquake studies and support a dilatant earthquake mechanism model.

Quasi-periodic recurrence of large earthquakes on the southern San Andreas fault

Science.gov (United States)

Scharer, Katherine M.; Biasi, Glenn P.; Weldon, Ray J.; Fumal, Tom E.

2010-01-01

It has been 153 yr since the last large earthquake on the southern San Andreas fault (California, United States), but the average interseismic interval is only ~100 yr. If the recurrence of large earthquakes is periodic, rather than random or clustered, the length of this period is notable and would generally increase the risk estimated in probabilistic seismic hazard analyses. Unfortunately, robust characterization of a distribution describing earthquake recurrence on a single fault is limited by the brevity of most earthquake records. Here we use statistical tests on a 3000 yr combined record of 29 ground-rupturing earthquakes from Wrightwood, California. We show that earthquake recurrence there is more regular than expected from a Poisson distribution and is not clustered, leading us to conclude that recurrence is quasi-periodic. The observation of unimodal time dependence is persistent across an observationally based sensitivity analysis that critically examines alternative interpretations of the geologic record. The results support formal forecast efforts that use renewal models to estimate probabilities of future earthquakes on the southern San Andreas fault. Only four intervals (15%) from the record are longer than the present open interval, highlighting the current hazard posed by this fault.

The accommodation of relative motion at depth on the San Andreas fault system in California

Science.gov (United States)

Prescott, W. H.; Nur, A.

1981-01-01

Plate motion below the seismogenic layer along the San Andreas fault system in California is assumed to form by aseismic slip along a deeper extension of the fault or may result from lateral distribution of deformation below the seismogenic layer. The shallow depth of California earthquakes, the depth of the coseismic slip during the 1906 San Francisco earthquake, and the presence of widely separated parallel faults indicate that relative motion is distributed below the seismogenic zone, occurring by inelastic flow rather than by aseismic slip on discrete fault planes.

Mantle strength of the San Andreas fault system and the role of mantle-crust feedbacks

NARCIS (Netherlands)

Chatzaras, V.; Tikoff, B.; Newman, J.; Withers, A.C.; Drury, M.R.

2015-01-01

In lithospheric-scale strike-slip fault zones, upper crustal strength is well constrained from borehole observations and fault rock deformation experiments, but mantle strength is less well known. Using peridotite xenoliths, we show that the upper mantle below the San Andreas fault system

Geomorphology, denudation rates, and stream channel profiles reveal patterns of mountain building adjacent to the San Andreas fault in northern California, USA

Science.gov (United States)

DeLong, Stephen B.; Hilley, George E.; Prentice, Carol S.; Crosby, Christopher J.; Yokelson, Intan N.

2017-01-01

Relative horizontal motion along strike-slip faults can build mountains when motion is oblique to the trend of the strike-slip boundary. The resulting contraction and uplift pose off-fault seismic hazards, which are often difficult to detect because of the poor vertical resolution of satellite geodesy and difficulty of locating offset datable landforms in active mountain ranges. Sparse geomorphic markers, topographic analyses, and measurement of denudation allow us to map spatiotemporal patterns of uplift along the northern San Andreas fault. Between Jenner and Mendocino, California, emergent marine terraces found southwest of the San Andreas fault record late Pleistocene uplift rates between 0.20 and 0.45 mm yr–1 along much of the coast. However, on the northeast side of the San Andreas fault, a zone of rapid uplift (0.6–1.0 mm yr–1) exists adjacent to the San Andreas fault, but rates decay northeastward as the coast becomes more distant from the San Andreas fault. A newly dated 4.5 Ma shallow-marine deposit located at ∼500 m above sea level (masl) adjacent to the San Andreas fault is warped down to just 150 masl 15 km northeast of the San Andreas fault, and it is exposed at just 60–110 masl to the west of the fault. Landscape denudation rates calculated from abundance of cosmogenic radionuclides in fluvial sediment northeast of, and adjacent to, the San Andreas fault are 0.16–0.29 mm yr–1, but they are only 0.03–0.07 mm yr–1 west of the fault. Basin-average channel steepness and the denudation rates can be used to infer the erosive properties of the underlying bedrock. Calibrated erosion rates can then be estimated across the entire landscape using the spatial distribution of channel steepness with these erosive properties. The lower-elevation areas of this landscape that show high channel steepness (and hence calibrated erosion rate) are distinct from higher-elevation areas with systematically lower channel steepness and denudation rates

Interaction of the san jacinto and san andreas fault zones, southern california: triggered earthquake migration and coupled recurrence intervals.

Science.gov (United States)

Sanders, C O

1993-05-14

Two lines of evidence suggest that large earthquakes that occur on either the San Jacinto fault zone (SJFZ) or the San Andreas fault zone (SAFZ) may be triggered by large earthquakes that occur on the other. First, the great 1857 Fort Tejon earthquake in the SAFZ seems to have triggered a progressive sequence of earthquakes in the SJFZ. These earthquakes occurred at times and locations that are consistent with triggering by a strain pulse that propagated southeastward at a rate of 1.7 kilometers per year along the SJFZ after the 1857 earthquake. Second, the similarity in average recurrence intervals in the SJFZ (about 150 years) and in the Mojave segment of the SAFZ (132 years) suggests that large earthquakes in the northern SJFZ may stimulate the relatively frequent major earthquakes on the Mojave segment. Analysis of historic earthquake occurrence in the SJFZ suggests little likelihood of extended quiescence between earthquake sequences.

Periodic pulsing of characteristic microearthquakes on the San Andreas fault.

Science.gov (United States)

Nadeau, Robert M; McEvilly, Thomas V

2004-01-09

Deep fault slip information from characteristically repeating microearthquakes reveals previously unrecognized patterns of extensive, large-amplitude, long-duration, quasiperiodic repetition of aseismic events along much of a 175-kilometer segment of the central San Andreas fault. Pulsing occurs both in conjunction with and independent of transient slip from larger earthquakes. It extends to depths of approximately 10 to 11 kilometers but may be deeper, and it may be related to similar phenomena occurring in subduction zones. Over much of the study area, pulse onset periods also show a higher probability of larger earthquakes, which may provide useful information for earthquake forecasting.

The San Andreas Fault and a Strike-slip Fault on Europa

Science.gov (United States)

1998-01-01

The mosaic on the right of the south polar region of Jupiter's moon Europa shows the northern 290 kilometers (180 miles) of a strike-slip fault named Astypalaea Linea. The entire fault is about 810 kilometers (500 miles) long, the size of the California portion of the San Andreas fault on Earth which runs from the California-Mexico border north to the San Francisco Bay. The left mosaic shows the portion of the San Andreas fault near California's san Francisco Bay that has been scaled to the same size and resolution as the Europa image. Each covers an area approximately 170 by 193 kilometers(105 by 120 miles). The red line marks the once active central crack of the Europan fault (right) and the line of the San Andreas fault (left). A strike-slip fault is one in which two crustal blocks move horizontally past one another, similar to two opposing lanes of traffic. The overall motion along the Europan fault seems to have followed a continuous narrow crack along the entire length of the feature, with a path resembling stepson a staircase crossing zones which have been pulled apart. The images show that about 50 kilometers (30 miles) of displacement have taken place along the fault. Opposite sides of the fault can be reconstructed like a puzzle, matching the shape of the sides as well as older individual cracks and ridges that had been broken by its movements. Bends in the Europan fault have allowed the surface to be pulled apart. This pulling-apart along the fault's bends created openings through which warmer, softer ice from below Europa's brittle ice shell surface, or frozen water from a possible subsurface ocean, could reach the surface. This upwelling of material formed large areas of new ice within the boundaries of the original fault. A similar pulling apart phenomenon can be observed in the geological trough surrounding California's Salton Sea, and in Death Valley and the Dead Sea. In those cases, the pulled apart regions can include upwelled materials, but may

Simulations of tremor-related creep reveal a weak crustal root of the San Andreas Fault

Science.gov (United States)

Shelly, David R.; Bradley, Andrew M.; Johnson, Kaj M.

2013-01-01

Deep aseismic roots of faults play a critical role in transferring tectonic loads to shallower, brittle crustal faults that rupture in large earthquakes. Yet, until the recent discovery of deep tremor and creep, direct inference of the physical properties of lower-crustal fault roots has remained elusive. Observations of tremor near Parkfield, CA provide the first evidence for present-day localized slip on the deep extension of the San Andreas Fault and triggered transient creep events. We develop numerical simulations of fault slip to show that the spatiotemporal evolution of triggered tremor near Parkfield is consistent with triggered fault creep governed by laboratory-derived friction laws between depths of 20–35 km on the fault. Simulated creep and observed tremor northwest of Parkfield nearly ceased for 20–30 days in response to small coseismic stress changes of order 104 Pa from the 2003 M6.5 San Simeon Earthquake. Simulated afterslip and observed tremor following the 2004 M6.0 Parkfield earthquake show a coseismically induced pulse of rapid creep and tremor lasting for 1 day followed by a longer 30 day period of sustained accelerated rates due to propagation of shallow afterslip into the lower crust. These creep responses require very low effective normal stress of ~1 MPa on the deep San Andreas Fault and near-neutral-stability frictional properties expected for gabbroic lower-crustal rock.

Crustal Deformation along San Andreas Fault System revealed by GPS and Sentinel-1 InSAR

Science.gov (United States)

Xu, X.; Sandwell, D. T.

2017-12-01

We present a crustal deformation velocity map along the San Andreas Fault System by combining measurements from Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR) and Global Positioning System (GPS) velocity models (CGM V1). We assembled 5 tracks of descending Sentinel-1 InSAR data spanning 2014.11-2017.02, and produced 545 interferograms, each of which covers roughly 250km x 420km area ( 60 bursts). These interferograms are unwrapped using SNAPHU [Chen & Zebker, 2002], with the 2Npi unwrapping ambiguity corrected with a sparse recovery method. We used coherence-based small baseline subset (SBAS) method [Tong & Schmidt, 2016] together with atmospheric correction by common-point stacking [Tymofyeyeva and Fialko, 2015] to construct deformation time series [Xu et. al., 2017]. Then we project the horizontal GPS model and vertical GPS data into satellite line-of-sight directions separately. We first remove the horizontal GPS model from InSAR measurements and perform elevation-dependent atmospheric phase correction. Then we compute the discrepancy between the remaining InSAR measurements and vertical GPS data. We interpolate this discrepancy and remove it from the residual InSAR measurements. Finally, we restore the horizontal GPS model. Preliminary results show that fault creep over the San Jacinto fault, the Elsinore fault, and the San Andreas creeping section is clearly resolved. During the period of drought, the Central Valley of California was subsiding at a high rate (up to 40 cm/yr), while the city of San Jose is uplifting due to recharge, with a quaternary fault acting as a ground water barrier. These findings will be reported during the meeting.

Earthquake Swarm Along the San Andreas Fault near Palmdale, Southern California, 1976 to 1977.

Science.gov (United States)

McNally, K C; Kanamori, H; Pechmann, J C; Fuis, G

1978-09-01

Between November 1976 and November 1977 a swarm of small earthquakes (local magnitude 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 earthquake faulting, the implications of the swarm for future large earthquakes on the San Andreas fault are unknown.

Cradle of the Earthquake: Exploring the Underwater San Andreas Fault on the R/V Pacific Storm and the SRV Derek M. Baylis between 20100910 and 20101003

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Over one hundred years after the devastating Great 1906 Earthquake that nearly destroyed San Francisco, this expedition explored the Northern San Andreas Fault, the...

The San Andreas fault experiment. [gross tectonic plates relative velocity

Science.gov (United States)

Smith, D. E.; Vonbun, F. O.

1973-01-01

A plan was developed during 1971 to determine gross tectonic plate motions along the San Andreas Fault System in California. Knowledge of the gross motion along the total fault system is an essential component in the construction of realistic deformation models of fault regions. Such mathematical models will be used in the future for studies which will eventually lead to prediction of major earthquakes. The main purpose of the experiment described is the determination of the relative velocity of the North American and the Pacific Plates. This motion being so extremely small, cannot be measured directly but can be deduced from distance measurements between points on opposite sites of the plate boundary taken over a number of years.

(U-Th)/He thermochronometry reveals Pleistocene punctuated deformation and synkinematic hematite mineralization in the Mecca Hills, southernmost San Andreas Fault zone

Science.gov (United States)

Moser, Amy C.; Evans, James P.; Ault, Alexis K.; Janecke, Susanne U.; Bradbury, Kelly K.

2017-10-01

The timing, tempo, and processes of punctuated deformation in strike-slip fault systems are challenging to resolve in the rock record. Faults in the Mecca Hills, adjacent to the southernmost San Andreas Fault, California, accommodate active deformation and exhumation in the Plio-Pleistocene sedimentary rocks and underlying crystalline basement. We document the spatiotemporal patterns of San Andreas Fault-related deformation as recorded in crystalline basement rocks of the Mecca Hills using fault microstructural observations, geochemical data, and hematite (n = 24) and apatite (n = 44) (U-Th)/He (hematite He, apatite He) thermochronometry data. Reproducible mean hematite He dates from minor hematite-coated fault surfaces in the Painted Canyon Fault damage zone range from ∼0.7-0.4 Ma and are younger than ∼1.2 Ma apatite He dates from adjacent crystalline basement host rock. These data reveal concomitant Pleistocene pulses of fault slip, fluid flow, and synkinematic hematite mineralization. Hematite textures, crystal morphology, and hematite He data patterns imply some damage zone deformation occurred via cyclic crack-seal and creep processes. Apatite He data from crystalline basement define distinct date-eU patterns and indicate cooling across discrete fault blocks in the Mecca Hills. Uniform ∼1.2 Ma apatite He dates regardless of eU are located exclusively between the Painted Canyon and Platform faults. Outside of this fault block, samples yield individual apatite He dates from ∼30-1 Ma that define a positive apatite He date-eU correlation. These patterns reveal focused exhumation away from the main trace of the San Andreas Fault at ∼1.2 Ma. Low-temperature thermochronometry of fault-related rocks provides an unprecedented window into the 105-106-yr record of San Andreas Fault-related deformation in the Mecca Hills and documents hematite deformation mechanisms that may be operative in other strike-slip faults world-wide.

Tremor-tide correlations and near-lithostatic pore pressure on the deep San Andreas fault.

Science.gov (United States)

Thomas, Amanda M; Nadeau, Robert M; Bürgmann, Roland

2009-12-24

Since its initial discovery nearly a decade ago, non-volcanic tremor has provided information about a region of the Earth that was previously thought incapable of generating seismic radiation. A thorough explanation of the geologic process responsible for tremor generation has, however, yet to be determined. Owing to their location at the plate interface, temporal correlation with geodetically measured slow-slip events and dominant shear wave energy, tremor observations in southwest Japan have been interpreted as a superposition of many low-frequency earthquakes that represent slip on a fault surface. Fluids may also be fundamental to the failure process in subduction zone environments, as teleseismic and tidal modulation of tremor in Cascadia and Japan and high Poisson ratios in both source regions are indicative of pressurized pore fluids. Here we identify a robust correlation between extremely small, tidally induced shear stress parallel to the San Andreas fault and non-volcanic tremor activity near Parkfield, California. We suggest that this tremor represents shear failure on a critically stressed fault in the presence of near-lithostatic pore pressure. There are a number of similarities between tremor in subduction zone environments, such as Cascadia and Japan, and tremor on the deep San Andreas transform, suggesting that the results presented here may also be applicable in other tectonic settings.

The morphology of strike-slip faults - Examples from the San Andreas Fault, California

Science.gov (United States)

Bilham, Roger; King, Geoffrey

1989-01-01

The dilatational strains associated with vertical faults embedded in a horizontal plate are examined in the framework of fault kinematics and simple displacement boundary conditions. Using boundary element methods, a sequence of examples of dilatational strain fields associated with commonly occurring strike-slip fault zone features (bends, offsets, finite rupture lengths, and nonuniform slip distributions) is derived. The combinations of these strain fields are then used to examine the Parkfield region of the San Andreas fault system in central California.

San Andreas-sized Strike-slip Fault on Europa

Science.gov (United States)

1998-01-01

This mosaic of the south polar region of Jupiter's moon Europa shows the northern 290 kilometers (180 miles) of a strike-slip fault named Astypalaea Linea. The entire fault is about 810 kilometers (500 miles) long, about the size of the California portion of the San Andreas fault, which runs from the California-Mexico border north to the San Francisco Bay. In a strike-slip fault, two crustal blocks move horizontally past one another, similar to two opposing lanes of traffic. Overall motion along the fault seems to have followed a continuous narrow crack along the feature's entire length, with a path resembling steps on a staircase crossing zones that have been pulled apart. The images show that about 50 kilometers (30 miles) of displacement have taken place along the fault. The fault's opposite sides can be reconstructed like a puzzle, matching the shape of the sides and older, individual cracks and ridges broken by its movements. [figure removed for brevity, see original site] The red line marks the once active central crack of the fault. The black line outlines the fault zone, including material accumulated in the regions which have been pulled apart. Bends in the fault have allowed the surface to be pulled apart. This process created openings through which warmer, softer ice from below Europa's brittle ice shell surface, or frozen water from a possible subsurface ocean, could reach the surface. This upwelling of material formed large areas of new ice within the boundaries of the original fault. A similar pulling-apart phenomenon can be observed in the geological trough surrounding California's Salton Sea, in Death Valley and the Dead Sea. In those cases, the pulled-apart regions can include upwelled materials, but may be filled mostly by sedimentary and eroded material from above. One theory is that fault motion on Europa is induced by the pull of variable daily tides generated by Jupiter's gravitational tug on Europa. Tidal tension opens the fault and

Constraints on the stress state of the San Andreas fault with analysis based on core and cuttings from SAFOD drilling phases I and II

Science.gov (United States)

Lockner, David A.; Tembe, Cheryl; Wong, Teng-fong

2009-01-01

Analysis of field data has led different investigators to conclude that the San Andreas Fault (SAF) has either anomalously low frictional sliding strength (m 0.6). Arguments for the apparent weakness of the SAF generally hinge on conceptual models involving intrinsically weak gouge or elevated pore pressure within the fault zone. Some models assert that weak gouge and/or high pore pressure exist under static conditions while others consider strength loss or fluid pressure increase due to rapid coseismic fault slip. The present paper is composed of three parts. First, we develop generalized equations, based on and consistent with the Rice (1992) fault zone model to relate stress orientation and magnitude to depth-dependent coefficient of friction and pore pressure. Second, we present temperature- and pressure-dependent friction measurements from wet illite-rich fault gouge extracted from San Andreas Fault Observatory at Depth (SAFOD) phase 1 core samples and from weak minerals associated with the San Andreas Fault. Third, we reevaluate the state of stress on the San Andreas Fault in light of new constraints imposed by SAFOD borehole data. Pure talc (m0.1) had the lowest strength considered and was sufficiently weak to satisfy weak fault heat flow and stress orientation constraints with hydrostatic pore pressure. Other fault gouges showed a systematic increase in strength with increasing temperature and pressure. In this case, heat flow and stress orientation constraints would require elevated pore pressure and, in some cases, fault zone pore pressure in excess of vertical stress.

Impulsive radon emanation on a creeping segment of the San Andreas fault, California

International Nuclear Information System (INIS)

King, C.-Y.

1984-01-01

Radon emanation was continuously monitored for several months at two locations along a creeping segment of the San Andreas fault in central California. The recorded emanations showed several impulsive increases that lasted as much as five hours with amplitudes considerably larger than meteorologically induced diurnal variations. Some of the radon increases were accompanied or followed by earthquakes or fault-creep events. They were possibly the result of some sudden outbursts of relatively radon-rich ground gas, sometimes triggered by crustal deformation or vibration. (Auth.)

Geomorphic evidence of active tectonics in the San Gorgonio Pass region of the San Andreas Fault system: an example of discovery-based research in undergraduate teaching

Science.gov (United States)

Reinen, L. A.; Yule, J. D.

2014-12-01

Student-conducted research in courses during the first two undergraduate years can increase learning and improve student self-confidence in scientific study, and is recommended for engaging and retaining students in STEM fields (PCAST, 2012). At Pomona College, incorporating student research throughout the geology curriculum tripled the number of students conducting research prior to their senior year that culminated in a professional conference presentation (Reinen et al., 2006). Here we present an example of discovery-based research in Neotectonics, a second-tier course predominantly enrolling first-and second-year students; describe the steps involved in the four week project; and discuss early outcomes of student confidence, engagement and retention. In the San Gorgonio Pass region (SGPR) in southern California, the San Andreas fault undergoes a transition from predominantly strike-slip to a complex system of faults with significant dip-slip, resulting in diffuse deformation and raising the question of whether a large earthquake on the San Andreas could propagate through the region (Yule, 2009). In spring 2014, seven students in the Neotectonics course conducted original research investigating quantifiable geomorphic evidence of tectonic activity in the SGPR. Students addressed questions of [1] unequal uplift in the San Bernardino Mountains, [2] fault activity indicated by stream knick points, [3] the role of fault style on mountain front sinuosity, and [4] characteristic earthquake slip determined via fault scarp degradation models. Students developed and revised individual projects, collaborated with each other on methods, and presented results in a public forum. A final class day was spent reviewing the projects and planning future research directions. Pre- and post-course surveys show increases in students' self-confidence in the design, implementation, and presentation of original scientific inquiries. 5 of 6 eligible students participated in research the

Tilt Precursors before Earthquakes on the San Andreas Fault, California.

Science.gov (United States)

Johnston, M J; Mortensen, C E

1974-12-13

An array of 14 biaxial shallow-borehole tiltmeters (at 1O(-7) radian sensitivity) has been installed along 85 kilometers of the San Andreas fault during the past year. Earthquake-related changes in tilt have been simultaneously observed on up to four independent instruments. At earthquake distances greater than 10 earthquake source dimensions, there are few clear indications of tilt change. For the four instruments with the longest records (> 10 months), 26 earthquakes have occurred since July 1973 with at least one instrument closer than 10 source dimensions and 8 earthquakes with more than one instrument within that distance. Precursors in tilt direction have been observed before more than 10 earthquakes or groups of earthquakes, and no similar effect has yet been seen without the occurrence of an earthquake.

Sawtooth segmentation and deformation processes on the southern San Andreas fault, California

Science.gov (United States)

Bilham, R.; Williams, P.

1985-01-01

Five contiguous 12-13 km fault segments form a sawtooth geometry on the southernmost San Andreas fault. The kinematic and morphologic properties of each segment depend on fault strike, despite differences of strike between segments of as little as 3 degrees. Oblique slip (transpression) of fault segments within the Indio Hills, Mecca Hills and Durmid Hill results from an inferred 8:1 ratio of dextral slip to convergence across the fault zone. Triggered slip and creep are confined almost entirely to transpressive segments of the fault. Durmid Hill has been formed in the last 28 + or - 6 ka by uplift at an average rate of 3 + or - 1 mm/a.

Fault rocks from the SAFOD core samples : implications for weakening at shallow depths along the San Andreas Fault, California

NARCIS (Netherlands)

Holdsworth, R.E.; van Diggelen, E.W.E.; Spiers, C.J.; Bresser, J.H.P. de; Walker, R.J.; Bown, L.

2011-01-01

The drilling of a deep borehole across the actively creeping Parkfield segment of the San Andreas Fault Zone (SAFZ), California, and collection of core materials permit direct geological study of fault zone processes at 2–3 km depth. The three drill cores sample both host and fault rocks and pass

Pleistocene Brawley and Ocotillo Formations: Evidence for initial strike-slip deformation along the San Felipe and San Jacinto fault zonez, Southern California

Science.gov (United States)

Kirby, S.M.; Janecke, S.U.; Dorsey, R.J.; Housen, B.A.; Langenheim, V.E.; McDougall, K.A.; Steeley, A.N.

2007-01-01

We examine the Pleistocene tectonic reorganization of the Pacific-North American plate boundary in the Salton Trough of southern California with an integrated approach that includes basin analysis, magnetostratigraphy, and geologic mapping of upper Pliocene to Pleistocene sedimentary rocks in the San Felipe Hills. These deposits preserve the earliest sedimentary record of movement on the San Felipe and San Jacinto fault zones that replaced and deactivated the late Cenozoic West Salton detachment fault. Sandstone and mudstone of the Brawley Formation accumulated between ???1.1 and ???0.6-0.5 Ma in a delta on the margin of an arid Pleistocene lake, which received sediment from alluvial fans of the Ocotillo Formation to the west-southwest. Our analysis indicates that the Ocotillo and Brawley formations prograded abruptly to the east-northeast across a former mud-dominated perennial lake (Borrego Formation) at ???1.1 Ma in response to initiation of the dextral-oblique San Felipe fault zone. The ???25-km-long San Felipe anticline initiated at about the same time and produced an intrabasinal basement-cored high within the San Felipe-Borrego basin that is recorded by progressive unconformities on its north and south limbs. A disconformity at the base of the Brawley Formation in the eastern San Felipe Hills probably records initiation and early blind slip at the southeast tip of the Clark strand of the San Jacinto fault zone. Our data are consistent with abrupt and nearly synchronous inception of the San Jacinto and San Felipe fault zones southwest of the southern San Andreas fault in the early Pleistocene during a pronounced southwestward broadening of the San Andreas fault zone. The current contractional geometry of the San Jacinto fault zone developed after ???0.5-0.6 Ma during a second, less significant change in structural style. ?? 2007 by The University of Chicago. All rights reserved.

Steep-dip seismic imaging of the shallow San Andreas fault near Parkfield.

Science.gov (United States)

Hole, J A; Catchings, R D; St Clair, K C; Rymer, M J; Okaya, D A; Carney, B J

2001-11-16

Seismic reflection and refraction images illuminate the San Andreas Fault to a depth of 1 kilometer. The prestack depth-migrated reflection image contains near-vertical reflections aligned with the active fault trace. The fault is vertical in the upper 0.5 kilometer, then dips about 70 degrees to the southwest to at least 1 kilometer subsurface. This dip reconciles the difference between the computed locations of earthquakes and the surface fault trace. The seismic velocity cross section shows strong lateral variations. Relatively low velocity (10 to 30%), high electrical conductivity, and low density indicate a 1-kilometer-wide vertical wedge of porous sediment or fractured rock immediately southwest of the active fault trace.

San Andreas Fault, Southern California , Radar Image, Wrapped Color as Height

Science.gov (United States)

2000-01-01

This topographic radar image vividly displays California's famous San Andreas Fault along the southwestern edge of the Mojave Desert, 75 kilometers (46 miles) north of downtown Los Angeles. The entire segment of the fault shown in this image last ruptured during the Fort Tejon earthquake of 1857. This was one of the greatest earthquakes ever recorded in the U.S., and it left an amazing surface rupture scar over 350 kilometers in length along the San Andreas. Were the Fort Tejon shock to happen today, the damage would run into billions of dollars, and the loss of life would likely be substantial, as the communities of Wrightwood, Palmdale, and Lancaster (among others) all lie upon or near the 1857 rupture area. The Lancaster/Palmdale area appears as bright patches just below the center of the image and the San Gabriel Mountains fill the lower left half of the image. At the extreme lower left is Pasadena. High resolution topographic data such as these are used by geologists to study the role of active tectonics in shaping the landscape, and to produce earthquake hazard maps.This image combines two types of data from the Shuttle Radar Topography Mission. The image brightness corresponds to the strength of the radar signal reflected from the ground, while colors show the elevation as measured by SRTM. Each cycle of colors (from pink through blue back to pink) represents an equal amount of elevation difference (400 meters, or 1300 feet) similar to contour lines on a standard topographic map. This image contains about 2400 meters (8000 feet) of total relief.The Shuttle Radar Topography Mission (SRTM), launched on February 11,2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an

Subsurface geometry of the San Andreas-Calaveras fault junction: influence of serpentinite and the Coast Range Ophiolite

Science.gov (United States)

Watt, Janet Tilden; Ponce, David A.; Graymer, Russell W.; Jachens, Robert C.; Simpson, Robert W.

2014-01-01

While an enormous amount of research has been focused on trying to understand the geologic history and neotectonics of the San Andreas-Calaveras fault (SAF-CF) junction, fundamental questions concerning fault geometry and mechanisms for slip transfer through the junction remain. We use potential-field, geologic, geodetic, and seismicity data to investigate the 3-D geologic framework of the SAF-CF junction and identify potential slip-transferring structures within the junction. Geophysical evidence suggests that the San Andreas and Calaveras fault zones dip away from each other within the northern portion of the junction, bounding a triangular-shaped wedge of crust in cross section. This wedge changes shape to the south as fault geometries change and fault activity shifts between fault strands, particularly along the Calaveras fault zone (CFZ). Potential-field modeling and relocated seismicity suggest that the Paicines and San Benito strands of the CFZ dip 65° to 70° NE and form the southwest boundary of a folded 1 to 3 km thick tabular body of Coast Range Ophiolite (CRO) within the Vallecitos syncline. We identify and characterize two steeply dipping, seismically active cross structures within the junction that are associated with serpentinite in the subsurface. The architecture of the SAF-CF junction presented in this study may help explain fault-normal motions currently observed in geodetic data and help constrain the seismic hazard. The abundance of serpentinite and related CRO in the subsurface is a significant discovery that not only helps constrain the geometry of structures but may also help explain fault behavior and the tectonic evolution of the SAF-CF junction.

Fracture surface energy of the Punchbowl fault, San Andreas system.

Science.gov (United States)

Chester, Judith S; Chester, Frederick M; Kronenberg, Andreas K

2005-09-01

Fracture energy is a form of latent heat required to create an earthquake rupture surface and is related to parameters governing rupture propagation and processes of slip weakening. Fracture energy has been estimated from seismological and experimental rock deformation data, yet its magnitude, mechanisms of rupture surface formation and processes leading to slip weakening are not well defined. Here we quantify structural observations of the Punchbowl fault, a large-displacement exhumed fault in the San Andreas fault system, and show that the energy required to create the fracture surface area in the fault is about 300 times greater than seismological estimates would predict for a single large earthquake. If fracture energy is attributed entirely to the production of fracture surfaces, then all of the fracture surface area in the Punchbowl fault could have been produced by earthquake displacements totalling <1 km. But this would only account for a small fraction of the total energy budget, and therefore additional processes probably contributed to slip weakening during earthquake rupture.

Electromagnetic Imaging of Fluids in the San Andreas Fault; FINAL

International Nuclear Information System (INIS)

Martyn Unsworth

2002-01-01

OAK 270 - Magnetotelluric data were collected on six profiles across the san Andreas Fault at Cholame,Parkfield, and Hollister in Central California. On each profile, high electrical resistivities were imaged west of the fault, and are due to granitic rocks of the Salinian block. East of the fault, lower electrical resistivities are associated with rocks of the Fanciscan formation. On the seismically active Parkfield and Hollister segments, a region of low resistivity was found in the fault zone that extends to a depth of several kilometers. This is due to a zone of fracturing (the damaged zone) that has been infiltrated by saline ground water. The shallowest micro-earthquakers occur at a depth that is coincident with the base of the low resistivity wedge. This strongly suggests that above this depth, the fault rocks are too weak to accumulate sufficient stress for earthquake rupture to occur and fault motion is accommodated through aseismic creep

Overview of SAFOD Phases 1 and 2: Drilling, Sampling and Measurements in the San Andreas Fault Zone at Seismogenic Depth

Science.gov (United States)

Zoback, M. D.; Hickman, S.; Ellsworth, W.

2005-12-01

In this talk we provide an overview of on-site drilling, sampling and downhole measurement activities associated with the first two Phases of the San Andreas Fault Observatory at Depth. SAFOD is located at the transition between the creeping and locked sections of the fault, 9 km NW of Parkfield, CA. A 2.1 km deep vertical pilot hole was drilled at the site in 2002. The SAFOD main borehole was drilled vertically to a depth of 1.5 km and then deviated at an average angle of 55° to vertical, passing beneath the surface trace of the San Andreas fault, 1.8 km to the NW at a depth of 3.2 km. Repeating microearthquakes on the San Andreas define the main active fault trace at depth, as well as a secondary active fault about 250 m to the SW (i.e., closer to SAFOD). The hole was rotary drilled, comprehensive cuttings were obtained and a real-time analysis of gases in the drilling mud was carried out. Spot cores were obtained at three depths (at casing set points) in the shallow granite and deeper sedimentary rocks penetrated by the hole, augmented by over fifty side-wall cores. Continuous coring of the San Andreas Fault Zone will be carried out in Phase 3 of the project in the summer of 2007. In addition to sampling mud gas, discrete fluid and gas samples were obtained at several depths for geochemical analysis. Real-time geophysical measurements were made while drilling through most of the San Andreas Fault Zone. A suite of "open hole" geophysical measurements were also made over essentially the entire depth of the hole. Construction of the multi-component SAFOD observatory is well underway, with a seismometer and tiltmeter operating at 1 km depth in the pilot hole and a fiber-optic laser strainmeter cemented behind casing in the main hole. A seismometer deployed at depth in the hole between Phases 1 and 2 detected one of the target earthquakes. A number of surface-to-borehole seismic experiments have been carried out to characterize seismic velocities and structures at

Southern San Andreas Fault evaluation field activity: approaches to measuring small geomorphic offsets--challenges and recommendations for active fault studies

Science.gov (United States)

Scharer, Katherine M.; Salisbury, J. Barrett; Arrowsmith, J. Ramon; Rockwell, Thomas K.

2014-01-01

In southern California, where fast slip rates and sparse vegetation contribute to crisp expression of faults and microtopography, field and high‐resolution topographic data (fault, analyze the offset values for concentrations or trends along strike, and infer that the common magnitudes reflect successive surface‐rupturing earthquakes along that fault section. Wallace (1968) introduced the use of such offsets, and the challenges in interpreting their “unique complex history” with offsets on the Carrizo section of the San Andreas fault; these were more fully mapped by Sieh (1978) and followed by similar field studies along other faults (e.g., Lindvall et al., 1989; McGill and Sieh, 1991). Results from such compilations spurred the development of classic fault behavior models, notably the characteristic earthquake and slip‐patch models, and thus constitute an important component of the long‐standing contrast between magnitude–frequency models (Schwartz and Coppersmith, 1984; Sieh, 1996; Hecker et al., 2013). The proliferation of offset datasets has led earthquake geologists to examine the methods and approaches for measuring these offsets, uncertainties associated with measurement of such features, and quality ranking schemes (Arrowsmith and Rockwell, 2012; Salisbury, Arrowsmith, et al., 2012; Gold et al., 2013; Madden et al., 2013). In light of this, the Southern San Andreas Fault Evaluation (SoSAFE) project at the Southern California Earthquake Center (SCEC) organized a combined field activity and workshop (the “Fieldshop”) to measure offsets, compare techniques, and explore differences in interpretation. A thorough analysis of the measurements from the field activity will be provided separately; this paper discusses the complications presented by such offset measurements using two channels from the San Andreas fault as illustrative cases. We conclude with best approaches for future data collection efforts based on input from the Fieldshop.

San Andreas Fault, Southern California, Shaded relief, wrapped color as height

Science.gov (United States)

2000-01-01

This topographic image vividly displays California's famous San Andreas Fault along the southwestern edge of the Mojave Desert, 75 kilometers (46 miles) north of downtown Los Angeles. The entire segment of the fault shown in this image last ruptured during the Fort Tejon earthquake of 1857. This was one of the greatest earthquakes ever recorded in the U.S., and it left an amazing surface rupture scar over 350 kilometers in length along the San Andreas. Were the Fort Tejon shock to happen today, the damage would run into billions of dollars, and the loss of life would likely be substantial, as the communities of Wrightwood, Palmdale, and Lancaster (among others) all lie upon or near the 1857 rupture area. The San Gabriel Mountains fill the lower left half of the image. At the extreme lower left is Pasadena. High resolution topographic data such as these are used by geologists to study the role of active tectonics in shaping the landscape, and to produce earthquake hazard maps.This image was generated using topographic data from the Shuttle Radar Topography Mission. Colors show the elevation as measured by SRTM. Each cycle of colors (from pink through blue back to pink) represents an equal amount of elevation difference (400 meters, or 1300 feet) similar to contour lines on a standard topographic map. This image contains about 2400 meters (8000 feet) of total relief. For the shading, a computer-generated artificial light source illuminates the elevation data to produce a pattern of light and shadows. Slopes facing the light appear bright, while those facing away are shaded. Shaded relief maps are commonly used in applications such as geologic mapping and land use planning.The Shuttle Radar Topography Mission (SRTM), launched on February 11,2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three

Periodic, chaotic, and doubled earthquake recurrence intervals on the deep San Andreas fault.

Science.gov (United States)

Shelly, David R

2010-06-11

Earthquake recurrence histories may provide clues to the timing of future events, but long intervals between large events obscure full recurrence variability. In contrast, small earthquakes occur frequently, and recurrence intervals are quantifiable on a much shorter time scale. In this work, I examine an 8.5-year sequence of more than 900 recurring low-frequency earthquake bursts composing tremor beneath the San Andreas fault near Parkfield, California. These events exhibit tightly clustered recurrence intervals that, at times, oscillate between approximately 3 and approximately 6 days, but the patterns sometimes change abruptly. Although the environments of large and low-frequency earthquakes are different, these observations suggest that similar complexity might underlie sequences of large earthquakes.

Periodic, chaotic, and doubled earthquake recurrence intervals on the deep San Andreas Fault

Science.gov (United States)

Shelly, David R.

2010-01-01

Earthquake recurrence histories may provide clues to the timing of future events, but long intervals between large events obscure full recurrence variability. In contrast, small earthquakes occur frequently, and recurrence intervals are quantifiable on a much shorter time scale. In this work, I examine an 8.5-year sequence of more than 900 recurring low-frequency earthquake bursts composing tremor beneath the San Andreas fault near Parkfield, California. These events exhibit tightly clustered recurrence intervals that, at times, oscillate between ~3 and ~6 days, but the patterns sometimes change abruptly. Although the environments of large and low-frequency earthquakes are different, these observations suggest that similar complexity might underlie sequences of large earthquakes.

Magnitude of shear stress on the san andreas fault: implications of a stress measurement profile at shallow depth.

Science.gov (United States)

Zoback, M D; Roller, J C

1979-10-26

A profile of measurements of shear stress perpendicular to the San Andreas fault near Palmdale, California, shows a marked increase in stress with distance from the fault. The pattern suggests that shear stress on the fault increases slowly with depth and reaches a value on the order of the average stress released during earthquakes. This result has important implications for both long- and shortterm prediction of large earthquakes.

Correlation of clayey gouge in a surface exposure of the San Andreas fault with gouge at depth from SAFOD: Implications for the role of serpentinite in fault mechanics

Science.gov (United States)

Moore, Diane E.; Rymer, Michael J.

2012-01-01

Magnesium-rich clayey gouge similar to that comprising the two actively creeping strands of the San Andreas Fault in drill core from the San Andreas Fault Observatory at Depth (SAFOD) has been identified in a nearby outcrop of serpentinite within the fault zone at Nelson Creek. Each occurrence of the gouge consists of porphyroclasts of serpentinite and sedimentary rocks dispersed in a fine-grained, foliated matrix of Mg-rich smectitic clays. The clay minerals in all three gouges are interpreted to be the product of fluid-assisted, shear-enhanced reactions between quartzofeldspathic wall rocks and serpentinite that was tectonically entrained in the fault from a source in the Coast Range Ophiolite. We infer that the gouge at Nelson Creek connects to one or both of the gouge zones in the SAFOD core, and that similar gouge may occur at depths in between. The special significance of the outcrop is that it preserves the early stages of mineral reactions that are greatly advanced at depth, and it confirms the involvement of serpentinite and the Mg-rich phyllosilicate minerals that replace it in promoting creep along the central San Andreas Fault.

Detection of aseismic creep along the San Andreas fault near Parkfield, California with ERS-1 radar interferometry

Science.gov (United States)

Werner, Charles L.; Rosen, Paul; Hensley, Scott; Fielding, Eric; Buckley, Sean

1997-01-01

The differential interferometric analysis of ERS data from Parkfield (CA) observations revealed the wide area distribution of creep along the moving fault segment of the San Andreas fault over a 15 month interval. The removal of the interferometric phase related to the surface topography was carried out. The fault was clearly visible in the differential interferogram. The magnitude of the tropospheric water vapor phase distortions is greater than the signal and hinders quantitative analysis beyond order of magnitude calculations.

Changes in state of stress on the southern san andreas fault resulting from the california earthquake sequence of april to june 1992.

Science.gov (United States)

Jaumé, S C; Sykes, L R

1992-11-20

The April to June 1992 Landers earthquake sequence in southern California modified the state of stress along nearby segments of the San Andreas fault, causing a 50-kilometer segment of the fault to move significantly closer to failure where it passes through a compressional bend near San Gorgonio Pass. The decrease in compressive normal stress may also have reduced fluid pressures along that fault segment. As pressures are reequilibrated by diffusion, that fault segment should move closer to failure with time. That fault segment and another to the southeast probably have not ruptured in a great earthquake in about 300 years.

Variations in strength and slip rate along the san andreas fault system.

Science.gov (United States)

Jones, C H; Wesnousky, S G

1992-04-03

Convergence across the San Andreas fault (SAF) system is partitioned between strike-slip motion on the vertical SAF and oblique-slip motion on parallel dip-slip faults, as illustrated by the recent magnitude M(s) = 6.0 Palm Springs, M(s) = 6.7 Coalinga, and M(s) = 7.1 Loma Prieta earthquakes. If the partitioning of slip minimizes the work done against friction, the direction of slip during these recent earthquakes depends primarily on fault dip and indicates that the normal stress coefficient and frictional coefficient (micro) vary among the faults. Additionally, accounting for the active dip-slip faults reduces estimates of fault slip rates along the vertical trace of the SAF by about 50 percent in the Loma Prieta and 100 percent in the North Palm Springs segments.

Tidal Sensitivity of Declustered Low Frequency Earthquake Families and Inferred Creep Episodes on the San Andreas Fault

Science.gov (United States)

Babb, A.; Thomas, A.; Bletery, Q.

2017-12-01

Low frequency earthquakes (LFEs) are detected at depths of 16-30 km on a 150 km section of the San Andreas Fault centered at Parkfield, CA. The LFEs are divided into 88 families based on waveform similarity. Each family is thought to represent a brittle asperity on the fault surface that repeatedly slips during aseismic slip of the surrounding fault. LFE occurrence is irregular which allows families to be divided into continuous and episodic. In continuous families a burst of a few LFE events recurs every few days while episodic families experience essentially quiescent periods often lasting months followed by bursts of hundreds of events over a few days. The occurrence of LFEs has also been shown to be sensitive to extremely small ( 1kPa) tidal stress perturbations. However, the clustered nature of LFE occurrence could potentially bias estimates of tidal sensitivity. Here we re-evaluate the tidal sensitivity of LFE families on the deep San Andreas using a declustered catalog. In this catalog LFE bursts are isolated based on the recurrence intervals between individual LFE events for each family. Preliminary analysis suggests that declustered LFE families are still highly sensitive to tidal stress perturbations, primarily right-lateral shear stress (RLSS) and to a lesser extent fault normal stress (FNS). We also find inferred creep episodes initiate preferentially during times of positive RLSS.

Vibroseis Monitoring of San Andreas Fault in California

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Korneev, Valeri; Nadeau, Robert

2004-06-11

A unique data set of seismograms for 720 source-receiver paths has been collected as part of a controlled source Vibroseis experiment San Andreas Fault (SAF) at Parkfield. In the experiment, seismic waves repeatedly illuminated the epicentral region of the expected M6 event at Parkfield from June 1987 until November 1996. For this effort, a large shear-wave vibrator was interfaced with the 3-component (3-C) borehole High-Resolution Seismic Network (HRSN), providing precisely timed collection of data for detailed studies of changes in wave propagation associated with stress and strain accumulation in the fault zone (FZ). Data collected by the borehole network were examined for evidence of changes associated with the nucleation process of the anticipated M6 earthquake at Parkfield. These investigations reported significant traveltime changes in the S coda for paths crossing the fault zone southeast of the epicenter and above the rupture zone of the 1966 M6 earthquake. Analysis and modeling of these data and comparison with observed changes in creep, water level, microseismicity, slip-at-depth and propagation from characteristic repeating microearthquakes showed temporal variations in a variety of wave propagation attributes that were synchronous with changes in deformation and local seismicity patterns. Numerical modeling suggests 200 meters as an effective thickness of SAF. The observed variations can be explained by velocity 6 percent velocity variation within SAF core. Numerical modeling studies and a growing number of observations have argued for the propagation of fault-zone guided waves (FZGW) within a SAF zone that is 100 to 200 m wide at seismogenic depths and with 20 to 40 percent lower shear-wave velocity than the adjacent unfaulted rock. Guided wave amplitude tomographic inversion for SAF using microearthquakes, shows clearly that FZGW are significantly less attenuated in a well-defined region of the FZ. This region plunges to the northwest along the

Deep-water turbidites as Holocene earthquake proxies: the Cascadia subduction zone and Northern San Andreas Fault systems

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J. E. Johnson

2003-06-01

Full Text Available New stratigraphic evidence from the Cascadia margin demonstrates that 13 earthquakes ruptured the margin from Vancouver Island to at least the California border following the catastrophic eruption of Mount Mazama. These 13 events have occurred with an average repeat time of ?? 600 years since the first post-Mazama event ?? 7500 years ago. The youngest event ?? 300 years ago probably coincides with widespread evidence of coastal subsidence and tsunami inundation in buried marshes along the Cascadia coast. We can extend the Holocene record to at least 9850 years, during which 18 events correlate along the same region. The pattern of repeat times is consistent with the pattern observed at most (but not all localities onshore, strengthening the contention that both were produced by plate-wide earthquakes. We also observe that the sequence of Holocene events in Cascadia may contain a repeating pattern, a tantalizing look at what may be the long-term behavior of a major fault system. Over the last ?? 7500 years, the pattern appears to have repeated at least three times, with the most recent A.D. 1700 event being the third of three events following a long interval of 845 years between events T4 and T5. This long interval is one that is also recognized in many of the coastal records, and may serve as an anchor point between the offshore and onshore records. Similar stratigraphic records are found in two piston cores and one box core from Noyo Channel, adjacent to the Northern San Andreas Fault, which show a cyclic record of turbidite beds, with thirty- one turbidite beds above a Holocene/.Pleistocene faunal «datum». Thus far, we have determined ages for 20 events including the uppermost 5 events from these cores. The uppermost event returns a «modern» age, which we interpret is likely the 1906 San Andreas earthquake. The penultimate event returns an intercept age of A.D. 1664 (2 ?? range 1505- 1822. The third event and fourth event

A 100-year average recurrence interval for the san andreas fault at wrightwood, california.

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Fumal, T E; Schwartz, D P; Pezzopane, S K; Weldon, R J

1993-01-08

Evidence for five large earthquakes during the past five centuries along the San Andreas fault zone 70 kilometers northeast of Los Angeles, California, indicates that the average recurrence interval and the temporal variability are significantly smaller than previously thought. Rapid sedimentation during the past 5000 years in a 150-meter-wide structural depression has produced a greater than 21-meter-thick sequence of debris flow and stream deposits interbedded with more than 50 datable peat layers. Fault scarps, colluvial wedges, fissure infills, upward termination of ruptures, and tilted and folded deposits above listric faults provide evidence for large earthquakes that occurred in A.D. 1857, 1812, and about 1700, 1610, and 1470.

Low resistivity and permeability in actively deforming shear zones on the San Andreas Fault at SAFOD

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Morrow, Carolyn A.; Lockner, David A.; Hickman, Stephen H.

2015-01-01

The San Andreas Fault Observatory at Depth (SAFOD) scientific drillhole near Parkfield, California crosses the San Andreas Fault at a depth of 2.7 km. Downhole measurements and analysis of core retrieved from Phase 3 drilling reveal two narrow, actively deforming zones of smectite-clay gouge within a roughly 200 m-wide fault damage zone of sandstones, siltstones and mudstones. Here we report electrical resistivity and permeability measurements on core samples from all of these structural units at effective confining pressures up to 120 MPa. Electrical resistivity (~10 ohm-m) and permeability (10-21 to 10-22 m2) in the actively deforming zones were one to two orders of magnitude lower than the surrounding damage zone material, consistent with broader-scale observations from the downhole resistivity and seismic velocity logs. The higher porosity of the clay gouge, 2 to 8 times greater than that in the damage zone rocks, along with surface conduction were the principal factors contributing to the observed low resistivities. The high percentage of fine-grained clay in the deforming zones also greatly reduced permeability to values low enough to create a barrier to fluid flow across the fault. Together, resistivity and permeability data can be used to assess the hydrogeologic characteristics of the fault, key to understanding fault structure and strength. The low resistivities and strength measurements of the SAFOD core are consistent with observations of low resistivity clays that are often found in the principal slip zones of other active faults making resistivity logs a valuable tool for identifying these zones.

Crustal Density Variation Along the San Andreas Fault Controls Its Secondary Faults Distribution and Dip Direction

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Yang, H.; Moresi, L. N.

2017-12-01

The San Andreas fault forms a dominant component of the transform boundary between the Pacific and the North American plate. The density and strength of the complex accretionary margin is very heterogeneous. Based on the density structure of the lithosphere in the SW United States, we utilize the 3D finite element thermomechanical, viscoplastic model (Underworld2) to simulate deformation in the San Andreas Fault system. The purpose of the model is to examine the role of a big bend in the existing geometry. In particular, the big bend of the fault is an initial condition of in our model. We first test the strength of the fault by comparing the surface principle stresses from our numerical model with the in situ tectonic stress. The best fit model indicates the model with extremely weak fault (friction coefficient 200 kg/m3) than surrounding blocks. In contrast, the Mojave block is detected to find that it has lost its mafic lower crust by other geophysical surveys. Our model indicates strong strain localization at the jointer boundary between two blocks, which is an analogue for the Garlock fault. High density lower crust material of the Great Valley tends to under-thrust beneath the Transverse Range near the big bend. This motion is likely to rotate the fault plane from the initial vertical direction to dip to the southwest. For the straight section, north to the big bend, the fault is nearly vertical. The geometry of the fault plane is consistent with field observations.

Geomorphic and geologic evidence for slip along the San Bernardino strand of the San Andreas Fault System through the San Gorgonio Pass structural knot, southern California

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Kendrick, K. J.; Matti, J. C.

2017-12-01

The San Gorgonio Pass (SGP) region of southern California represents an extraordinarily complex section of the San Andreas Fault (SAF) zone, often referred to as a structural knot. Complexity is expressed both structurally and geomorphically, and arises because multiple strands of the SAF have evolved here in Quaternary time. Our integration of geologic and geomorphic analyses led to recognition of multiple fault-bounded blocks characterized by crystalline rocks that have similar physical properties. Hence, any morphometric differences in hypsometric analysis, slope, slope distribution, texture, and stream-power measurements and discontinuities reflect landscape response to tectonic processes rather than differences in lithology. We propose that the differing morphometry of the two blocks on either side of the San Bernardino strand (SBS) of the SAF, the high-standing Kitching Peak block to the east and the lower, more subdued Pisgah Peak block to the west, strongly suggests that the blocks experienced different uplift histories. This difference in uplift histories, in turn suggests that dextral slip occurred over a long time interval on the SBS—despite long-lived controversy raised by the fact that, at the surface, a throughgoing trace of the SBS is not present at this location. A different tectonic history between the two blocks is consistent with the gravity data which indicate that low-density rocks underthrusting the Kitching Peak block are absent below the Pisgah Peak block (Langenheim et al., 2015). Throughgoing slip on the SBS implied by geomorphic differences between the two blocks is also consistent with displaced geologic and geomorphic features. We find compelling evidence for discrete offsets of between 0.6 and 6 km of dextral slip on the SBS, including offset of fluvial and landslide deposits, and beheaded drainages. Although we lack numerical age control for the offset features, the degree of soil development associated with displaced landforms

The Ash of Ohlson Ranch: A well-dated Stratigraphic Marker for Constraining Deformation Across the Northern San Andreas Fault

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McLaughlin, R. J.; Vazquez, J. A.; Fleck, R. J.; DeLong, S.; Sarna-Wojcicki, A.; Wan, E.; Powell, C., II; Prentice, C. S.

2012-12-01

The marine to non-marine transgressional - regressional Ohlson Ranch Formation of northern California was deposited mainly east of the San Andreas Fault and the Gualala structural block during Pliocene sea level high stands. The formation transitions eastward from marine to fluvial deposits and the marine strata are deposited on a mildly warped, pholad-bored erosional surface cut near Pliocene sea level (probably above storm wave-base), on rocks of the Coastal and Central belts of the Franciscan Complex. West of the San Andreas fault near Point Arena, a right-laterally displaced remnant of the wave-cut surface occurs at ca. 100m above modern sea level. East of the fault this surface varies in elevation from ca. 200-350m and a 12-15 cm thick light gray silicic tephra, the ash of Ohlson Ranch (AOR) locally occurs ~10m above the base of the marine section. The AOR consists of very fine-grained glass shards with conspicuous brown biotite in the upper 2 cm and rare co-magmatic clinopyroxene, hornblende and euhedral, weakly zoned zircons. The zircons are relatively uniform in size and little abraded, suggesting they are primary and not re-worked. The fine-grained nature of the AOR deposit suggests it is water lain and chemical analysis of the volcanic glass indicates that the eruptive source was in the southern Cascade Range. We analyzed both polished section mounts of zircon crystals and unpolished rims by ion microprobe (SHRIMP-RG) and LA-ICPMS in order to establish a precise U-Pb age for the AOR. Ages were adjusted for initial 230Th deficiency in the U-Pb chain using Th/U measured in zircon and host glass shards. Thirty-two zircon grains measured by LA-ICPMS at the University of Arizona LaserChron Center yield a mean U-Pb age of 4.58 ± 0.30 Ma (2σ , MSWD=0.53, n=23). SHRIMP analyses of zircon interiors exposed in polished epoxy-mounts yield a mean U-Pb age of 4.36 ± 0.11 Ma (2σ, MSWD 0.72, n=19). To further refine the likely eruption age of the AOR, the SHRIMP was

Geodetic measurement of deformation east of the San Andreas Fault in Central California

Science.gov (United States)

Sauber, Jeanne; Solomon, Sean C.; Lisowski, Michael

1988-01-01

The shear strain rates in the Diablo Range of California have been calculated, and the slip rate along the Calaveras and Paicines faults in Central California have been estimated, on the basis of triangulation and trilateration data from two geodetic networks located between the western edge of the Great Valley and the San Andreas Fault. The orientation of the principal compressive strain predicted from the azimuth of the major structures in the region is N 25 deg E, leading to an average shear strain value that corresponds to a relative shortening rate of 4.5 + or - 2.4 mm/yr. It is inferred that the measured strain is due to compression across the fold of this area. The hypothesized uniform, fault-normal compression within the Coast Ranges is not supported by these results.

A rheologically layered three-dimensional model of the San Andreas fault in central and southern California

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Williams, Charles A.; Richardson, Randall M.

1991-01-01

The effects of rheological parameters and the fault slip distribution on the horizontal and vertical deformation in the vicinity of the fault are investigated using 3D kinematic finite element models of the San Andreas fault in central and southern California. It is shown that fault models with different rheological stratification schemes and slip distributions predict characteristic deformation patterns. Models that do not include aseismic slip below the fault locking depth predict deformation patterns that are strongly dependent on time since the last earthquake, while models that incorporate the aseismic slip below the locking depth depend on time to a significantly lesser degree.

Incipient Evolution of the Eastern California Shear Zone through a Transpressional Zone along the San Andreas Fault in the San Bernardino Mountains, California

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Cochran, W. J.; Spotila, J. A.

2017-12-01

Measuring long-term accumulation of strike-slip displacements and transpressional uplift is difficult where strain is accommodated across wide shear zones, as opposed to a single major fault. The Eastern California Shear Zone (ECSZ) in southern California accommodates dextral shear across several strike-slip faults, and is potentially migrating and cutting through a formerly convergent zone of the San Bernardino Mountains (SBM). The advection of crust along the San Andreas fault to the SE has forced these two tectonic regimes into creating a nexus of interacting strike-slip faults north of San Gorgonio Pass. These elements make this region ideal for studying complex fault interactions, evolving fault geometries, and deformational overprinting within a wide shear zone. Using high-resolution topography and field mapping, this study aims to test whether diffuse, poorly formed strike-slip faults within the uplifted SBM block are nascent elements of the ECSZ. Topographic resolution of ≤ 1m was achieved using both lidar and UAV surveys along two Quaternary strike-slip faults, namely the Lake Peak fault and Lone Valley faults. Although the Lone Valley fault cuts across Quaternary alluvium, the geomorphic expression is obscured, and may be the result of slow slip rates. In contrast, the Lake Peak fault is located high elevations north of San Gorgonio Peak in the SBM, and displaces Quaternary glacial deposits. The deposition of large boulders along the escarpment also obscures the apparent magnitude of slip along the fault. Although determining fault offset is difficult, the Lake Peak fault does display evidence for minor right-lateral displacement, where the magnitude of slip would be consistent with individual faults within the ECSZ (i.e. ≤ 1 mm/yr). Compared to the preservation of displacement along strike-slip faults located within the Mojave Desert, the upland region of the SBM adds complexity for measuring fault offset. The distribution of strain across the entire

Observations of strain accumulation across the san andreas fault near palmdale, california, with a two-color geodimeter.

Science.gov (United States)

Langbein, J O; Linker, M F; McGarr, A; Slater, L E

1982-12-17

Two-color laser ranging measurements during a 15-month period over a geodetic network spanning the San Andreas fault near Palmdale, California, indicate that the crust expands and contracts aseismically in episodes as short as 2 weeks. Shear strain parallel to the fault has accumulated monotonically since November 1980, but at a variable rate. Improvements in measurement precision and temporal resolution over those of previous geodetic studies near Palmdale have resulted in the definition of a time history of crustal deformation that is much more complex than formerly realized.

Shallow deformation of the San Andreas fault 5 years following the 2004 Parkfield earthquake (Mw6) combining ERS2 and Envisat InSAR.

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Bacques, Guillaume; de Michele, Marcello; Raucoules, Daniel; Aochi, Hideo; Rolandone, Frédérique

2018-04-16

This study focuses on the shallow deformation that occurred during the 5 years following the Parkfield earthquake (28/09/2004, Mw 6, San Andreas Fault, California). We use Synthetic Aperture Radar interferometry (InSAR) to provide precise measurements of transient deformations after the Parkfield earthquake between 2005 and 2010. We propose a method to combine both ERS2 and ENVISAT interferograms to increase the temporal data sampling. Firstly, we combine 5 years of available Synthetic Aperture Radar (SAR) acquisitions including both ERS-2 and Envisat. Secondly, we stack selected interferograms (both from ERS2 and Envisat) for measuring the temporal evolution of the ground velocities at given time intervals. Thanks to its high spatial resolution, InSAR could provide new insights on the surface fault motion behavior over the 5 years following the Parkfield earthquake. As a complement to previous studies in this area, our results suggest that shallow transient deformations affected the Creeping-Parkfield-Cholame sections of the San Andreas Fault after the 2004 Mw6 Parkfield earthquake.

Fault Creep along the Southern San Andreas from Interferometric Synthetic Aperture Radar, Permanent Scatterers, and Stacking

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Lyons, Suzanne; Sandwell, David

2003-01-01

Interferometric synthetic aperture radar (InSAR) provides a practical means of mapping creep along major strike-slip faults. The small amplitude of the creep signal (less than 10 mm/yr), combined with its short wavelength, makes it difficult to extract from long time span interferograms, especially in agricultural or heavily vegetated areas. We utilize two approaches to extract the fault creep signal from 37 ERS SAR images along the southem San Andreas Fault. First, amplitude stacking is utilized to identify permanent scatterers, which are then used to weight the interferogram prior to spatial filtering. This weighting improves correlation and also provides a mask for poorly correlated areas. Second, the unwrapped phase is stacked to reduce tropospheric and other short-wavelength noise. This combined processing enables us to recover the near-field (approximately 200 m) slip signal across the fault due to shallow creep. Displacement maps fiom 60 interferograms reveal a diffuse secular strain buildup, punctuated by localized interseismic creep of 4-6 mm/yr line of sight (LOS, 12-18 mm/yr horizontal). With the exception of Durmid Hill, this entire segment of the southern San Andreas experienced right-lateral triggered slip of up to 10 cm during the 3.5-year period spanning the 1992 Landers earthquake. The deformation change following the 1999 Hector Mine earthquake was much smaller (4 cm) and broader than for the Landers event. Profiles across the fault during the interseismic phase show peak-to-trough amplitude ranging from 15 to 25 mm/yr (horizontal component) and the minimum misfit models show a range of creeping/locking depth values that fit the data.

A large mantle water source for the northern San Andreas Fault System: A ghost of subduction past

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Kirby, Stephen H.; Wang, Kelin; Brocher, Thomas M.

2014-01-01

Recent research indicates that the shallow mantle of the Cascadia subduction margin under near-coastal Pacific Northwest U.S. is cold and partially serpentinized, storing large quantities of water in this wedge-shaped region. Such a wedge probably formed to the south in California during an earlier period of subduction. We show by numerical modeling that after subduction ceased with the creation of the San Andreas Fault System (SAFS), the mantle wedge warmed, slowly releasing its water over a period of more than 25 Ma by serpentine dehydration into the crust above. This deep, long-term water source could facilitate fault slip in San Andreas System at low shear stresses by raising pore pressures in a broad region above the wedge. Moreover, the location and breadth of the water release from this model gives insights into the position and breadth of the SAFS. Such a mantle source of water also likely plays a role in the occurrence of Non-Volcanic Tremor (NVT) that has been reported along the SAFS in central California. This process of water release from mantle depths could also mobilize mantle serpentinite from the wedge above the dehydration front, permitting upward emplacement of serpentinite bodies by faulting or by diapiric ascent. Specimens of serpentinite collected from tectonically emplaced serpentinite blocks along the SAFS show mineralogical and structural evidence of high fluid pressures during ascent from depth. Serpentinite dehydration may also lead to tectonic mobility along other plate boundaries that succeed subduction, such as other continental transforms, collision zones, or along present-day subduction zones where spreading centers are subducting.

Seismic trapped modes in the oroville and san andreas fault zones.

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Li, Y G; Leary, P; Aki, K; Malin, P

1990-08-17

Three-component borehole seismic profiling of the recently active Oroville, California, normal fault and microearthquake event recording with a near-fault three-component borehole seismometer on the San Andreas fault at Parkfield, California, have shown numerous instances of pronounced dispersive wave trains following the shear wave arrivals. These wave trains are interpreted as fault zone-trapped seismic modes. Parkfield earthquakes exciting trapped modes have been located as deep as 10 kilometers, as shallow as 4 kilometers, and extend 12 kilometers along the fault on either side of the recording station. Selected Oroville and Parkfield wave forms are modeled as the fundamental and first higher trapped SH modes of a narrow low-velocity layer at the fault. Modeling results suggest that the Oroville fault zone is 18 meters wide at depth and has a shear wave velocity of 1 kilometer per second, whereas at Parkfield, the fault gouge is 100 to 150 meters wide and has a shear wave velocity of 1.1 to 1.8 kilometers per second. These low-velocity layers are probably the rupture planes on which earthquakes occur.

Tidal triggering of earthquakes suggests poroelastic behavior on the San Andreas Fault

International Nuclear Information System (INIS)

Delorey, Andrew A.; Elst, Nicholas J. van der; Johnson, Paul Allan

2016-01-01

Tidal triggering of earthquakes is hypothesized to provide quantitative information regarding the fault's stress state, poroelastic properties, and may be significant for our understanding of seismic hazard. To date, studies of regional or global earthquake catalogs have had only modest successes in identifying tidal triggering. We posit that the smallest events that may provide additional evidence of triggering go unidentified and thus we developed a technique to improve the identification of very small magnitude events. We identify events applying a method known as inter-station seismic coherence where we prioritize detection and discrimination over characterization. Here we show tidal triggering of earthquakes on the San Andreas Fault. We find the complex interaction of semi-diurnal and fortnightly tidal periods exposes both stress threshold and critical state behavior. Lastly, our findings reveal earthquake nucleation processes and pore pressure conditions – properties of faults that are difficult to measure, yet extremely important for characterizing earthquake physics and seismic hazards.

Tidal triggering of earthquakes suggests poroelastic behavior on the San Andreas Fault

Science.gov (United States)

Delorey, Andrew; Van Der Elst, Nicholas; Johnson, Paul

2017-01-01

Tidal triggering of earthquakes is hypothesized to provide quantitative information regarding the fault's stress state, poroelastic properties, and may be significant for our understanding of seismic hazard. To date, studies of regional or global earthquake catalogs have had only modest successes in identifying tidal triggering. We posit that the smallest events that may provide additional evidence of triggering go unidentified and thus we developed a technique to improve the identification of very small magnitude events. We identify events applying a method known as inter-station seismic coherence where we prioritize detection and discrimination over characterization. Here we show tidal triggering of earthquakes on the San Andreas Fault. We find the complex interaction of semi-diurnal and fortnightly tidal periods exposes both stress threshold and critical state behavior. Our findings reveal earthquake nucleation processes and pore pressure conditions – properties of faults that are difficult to measure, yet extremely important for characterizing earthquake physics and seismic hazards.

Clustering and periodic recurrence of microearthquakes on the san andreas fault at parkfield, california.

Science.gov (United States)

Nadeau, R M; Foxall, W; McEvilly, T V

1995-01-27

The San Andreas fault at Parkfield, California, apparently late in an interval between repeating magnitude 6 earthquakes, is yielding to tectonic loading partly by seismic slip concentrated in a relatively sparse distribution of small clusters (<20-meter radius) of microearthquakes. Within these clusters, which account for 63% of the earthquakes in a 1987-92 study interval, virtually identical small earthquakes occurred with a regularity that can be described by the statistical model used previously in forecasting large characteristic earthquakes. Sympathetic occurrence of microearthquakes in nearby clusters was observed within a range of about 200 meters at communication speeds of 10 to 100 centimeters per second. The rate of earthquake occurrence, particularly at depth, increased significantly during the study period, but the fraction of earthquakes that were cluster members decreased.

Holocene geologic slip rate for the Banning strand of the southern San Andreas Fault, southern California

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Gold, Peter O.; Behr, Whitney M.; Rood, Dylan; Sharp, Warren D.; Rockwell, Thomas; Kendrick, Katherine J.; Salin, Aaron

2015-01-01

Northwest directed slip from the southern San Andreas Fault is transferred to the Mission Creek, Banning, and Garnet Hill fault strands in the northwestern Coachella Valley. How slip is partitioned between these three faults is critical to southern California seismic hazard estimates but is poorly understood. In this paper, we report the first slip rate measured for the Banning fault strand. We constrain the depositional age of an alluvial fan offset 25 ± 5 m from its source by the Banning strand to between 5.1 ± 0.4 ka (95% confidence interval (CI)) and 6.4 + 3.7/−2.1 ka (95% CI) using U-series dating of pedogenic carbonate clast coatings and 10Be cosmogenic nuclide exposure dating of surface clasts. We calculate a Holocene geologic slip rate for the Banning strand of 3.9 + 2.3/−1.6 mm/yr (median, 95% CI) to 4.9 + 1.0/−0.9 mm/yr (median, 95% CI). This rate represents only 25–35% of the total slip accommodated by this section of the southern San Andreas Fault, suggesting a model in which slip is less concentrated on the Banning strand than previously thought. In rejecting the possibility that the Banning strand is the dominant structure, our results highlight an even greater need for slip rate and paleoseismic measurements along faults in the northwestern Coachella Valley in order to test the validity of current earthquake hazard models. In addition, our comparison of ages measured with U-series and 10Be exposure dating demonstrates the importance of using multiple geochronometers when estimating the depositional age of alluvial landforms.

Tremor reveals stress shadowing, deep postseismic creep, and depth-dependent slip recurrence on the lower-crustal San Andreas fault near Parkfield

Science.gov (United States)

Shelly, David R.; Johnson, Kaj M.

2011-01-01

The 2003 magnitude 6.5 San Simeon and the 2004 magnitude 6.0 Parkfield earthquakes induced small, but significant, static stress changes in the lower crust on the central San Andreas fault, where recently detected tectonic tremor sources provide new constraints on deep fault creep processes. We find that these earthquakes affect tremor rates very differently, consistent with their differing transferred static shear stresses. The San Simeon event appears to have cast a "stress shadow" north of Parkfield, where tremor activity was stifled for 3-6 weeks. In contrast, the 2004 Parkfield earthquake dramatically increased tremor activity rates both north and south of Parkfield, allowing us to track deep postseismic slip. Following this event, rates initially increased by up to two orders of magnitude for the relatively shallow tremor sources closest to the rupture, with activity in some sources persisting above background rates for more than a year. We also observe strong depth dependence in tremor recurrence patterns, with shallower sources generally exhibiting larger, less-frequent bursts, possibly signaling a transition toward steady creep with increasing temperature and depth. Copyright 2011 by the American Geophysical Union.

Evidence for chaotic fault interactions in the seismicity of the San Andreas fault and Nankai trough

Science.gov (United States)

Huang, Jie; Turcotte, D. L.

1990-01-01

The dynamical behavior introduced by fault interactions is examined here using a simple spring-loaded, slider-block model with velocity-weakening friction. The model consists of two slider blocks coupled to each other and to a constant-velocity driver by elastic springs. For an asymmetric system in which the frictional forces on the two blocks are not equal, the solutions exhibit chaotic behavior. The system's behavior over a range of parameter values seems to be generally analogous to that of weakly coupled segments of an active fault. Similarities between the model simulations and observed patterns of seismicity on the south central San Andreas fault in California and in the Nankai trough along the coast of southwestern Japan.

The Evergreen basin and the role of the Silver Creek fault in the San Andreas fault system, San Francisco Bay region, California

Science.gov (United States)

Jachens, Robert C.; Wentworth, Carl M.; Graymer, Russell W.; Williams, Robert; Ponce, David A.; Mankinen, Edward A.; Stephenson, William J.; Langenheim, Victoria

2017-01-01

The Evergreen basin is a 40-km-long, 8-km-wide Cenozoic sedimentary basin that lies mostly concealed beneath the northeastern margin of the Santa Clara Valley near the south end of San Francisco Bay (California, USA). The basin is bounded on the northeast by the strike-slip Hayward fault and an approximately parallel subsurface fault that is structurally overlain by a set of west-verging reverse-oblique faults which form the present-day southeastward extension of the Hayward fault. It is bounded on the southwest by the Silver Creek fault, a largely dormant or abandoned fault that splays from the active southern Calaveras fault. We propose that the Evergreen basin formed as a strike-slip pull-apart basin in the right step from the Silver Creek fault to the Hayward fault during a time when the Silver Creek fault served as a segment of the main route by which slip was transferred from the central California San Andreas fault to the Hayward and other East Bay faults. The dimensions and shape of the Evergreen basin, together with palinspastic reconstructions of geologic and geophysical features surrounding it, suggest that during its lifetime, the Silver Creek fault transferred a significant portion of the ∼100 km of total offset accommodated by the Hayward fault, and of the 175 km of total San Andreas system offset thought to have been accommodated by the entire East Bay fault system. As shown previously, at ca. 1.5–2.5 Ma the Hayward-Calaveras connection changed from a right-step, releasing regime to a left-step, restraining regime, with the consequent effective abandonment of the Silver Creek fault. This reorganization was, perhaps, preceded by development of the previously proposed basin-bisecting Mount Misery fault, a fault that directly linked the southern end of the Hayward fault with the southern Calaveras fault during extinction of pull-apart activity. Historic seismicity indicates that slip below a depth of 5 km is mostly transferred from the Calaveras

Modeling of periodic great earthquakes on the San Andreas fault: Effects of nonlinear crustal rheology

Science.gov (United States)

Reches, Ze'ev; Schubert, Gerald; Anderson, Charles

1994-01-01

We analyze the cycle of great earthquakes along the San Andreas fault with a finite element numerical model of deformation in a crust with a nonlinear viscoelastic rheology. The viscous component of deformation has an effective viscosity that depends exponentially on the inverse absolute temperature and nonlinearity on the shear stress; the elastic deformation is linear. Crustal thickness and temperature are constrained by seismic and heat flow data for California. The models are for anti plane strain in a 25-km-thick crustal layer having a very long, vertical strike-slip fault; the crustal block extends 250 km to either side of the fault. During the earthquake cycle that lasts 160 years, a constant plate velocity v(sub p)/2 = 17.5 mm yr is applied to the base of the crust and to the vertical end of the crustal block 250 km away from the fault. The upper half of the fault is locked during the interseismic period, while its lower half slips at the constant plate velocity. The locked part of the fault is moved abruptly 2.8 m every 160 years to simulate great earthquakes. The results are sensitive to crustal rheology. Models with quartzite-like rheology display profound transient stages in the velocity, displacement, and stress fields. The predicted transient zone extends about 3-4 times the crustal thickness on each side of the fault, significantly wider than the zone of deformation in elastic models. Models with diabase-like rheology behave similarly to elastic models and exhibit no transient stages. The model predictions are compared with geodetic observations of fault-parallel velocities in northern and central California and local rates of shear strain along the San Andreas fault. The observations are best fit by models which are 10-100 times less viscous than a quartzite-like rheology. Since the lower crust in California is composed of intermediate to mafic rocks, the present result suggests that the in situ viscosity of the crustal rock is orders of magnitude

Crustal structure of the coastal and marine San Francisco Bay region, California

Science.gov (United States)

Parsons, Tom

2002-01-01

As of the time of this writing, the San Francisco Bay region is home to about 6.8 million people, ranking fifth among population centers in the United States. Most of these people live on the coastal lands along San Francisco Bay, the Sacramento River delta, and the Pacific coast. The region straddles the tectonic boundary between the Pacific and North American Plates and is crossed by several strands of the San Andreas Fault system. These faults, which are stressed by about 4 cm of relative plate motion each year, pose an obvious seismic hazard.

Quaternary landscape development, alluvial fan chronology and erosion of the Mecca Hills at the southern end of the San Andreas Fault zone

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Gray, Harrison J.; Owen, Lewis A.; Dietsch, Craig; Beck, Richard A.; Caffee, Marc A.; Finkelman, Robert B.; Mahan, Shannon

2014-01-01

Quantitative geomorphic analysis combined with cosmogenic nuclide 10Be-based geochronology and denudation rates have been used to further the understanding of the Quaternary landscape development of the Mecca Hills, a zone of transpressional uplift along the southern end of the San Andreas Fault, in southern California. The similar timing of convergent uplifts along the San Andreas Fault with the initiation of the sub-parallel San Jacinto Fault suggest a possible link between the two tectonic events. The ages of alluvial fans and the rates of catchment-wide denudation have been integrated to assess the relative influence of climate and tectonic uplift on the development of catchments within the Mecca Hills. Ages for major geomorphic surfaces based on 10Be surface exposure dating of boulders and 10Be depth profiles define the timing of surface stabilization to 2.6 +5.6/–1.3 ka (Qyf1 surface), 67.2 ± 5.3 ka (Qvof2 surface), and 280 ± 24 ka (Qvof1 surface). Comparison of 10Be measurements from active channel deposits (Qac) and fluvial terraces (Qt) illustrate a complex history of erosion, sediment storage, and sediment transport in this environment. Beryllium-10 catchment-wide denudation rates range from 19.9 ± 3.2 to 149 ± 22.5 m/Ma and demonstrate strong correlations with mean catchment slope and with total active fault length normalized by catchment area. The lack of strong correlation with other geomorphic variables suggests that tectonic uplift and rock weakening have the greatest control. The currently measured topography and denudation rates across the Mecca Hills may be most consistent with a model of radial topographic growth in contrast to a model based on the rapid uplift and advection of crust.

Searching for geodetic transient slip signals along the Parkfield segment of the San Andreas Fault

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Rousset, B.; Burgmann, R.

2017-12-01

The Parkfield section of the San Andreas fault is at the transition between a segment locked since the 1857 Mw 7.9 Fort Tejon earthquake to its south and a creeping segment to the north. It is particularly well instrumented since it is the many previous studies have focused on studying the coseismic and postseismic phases of the two most recent earthquake cycles, the interseismic phase is exhibiting interesting dynamics at the down-dip edge of the seismogenic zone, characterized by a very large number of low frequency earthquakes (LFE) with different behaviors depending on location. Interseismic fault creep rates appear to vary over a wide range of spatial and temporal scales, from the Earth's surface to the base of crust. In this study, we take advantage of the dense Global Positioning System (GPS) network, with 77 continuous stations located within a circle of radius 80 km centered on Parkfield. We correct these time series for the co- and postseismic signals of the 2003 Mw 6.3 San Simeon and 2004 Mw 6.0 Parkfield earthquakes. We then cross-correlate the residual time series with synthetic slow-slip templates following the approach of Rousset et al. (2017). Synthetic tests with transient events contained in GPS time series with realistic noise show the limit of detection of the method. In the application with real GPS time series, the highest correlation amplitudes are compared with micro-seismicity rates, as well as tremor and LFE observations.

Seismic Evidence for Conjugate Slip and Block Rotation Within the San Andreas Fault System, Southern California

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Nicholson, Craig; Seeber, Leonardo; Williams, Patrick; Sykes, Lynn R.

1986-08-01

The pattern of seismicity in southern California indicates that much of the activity is presently occurring on secondary structures, several of which are oriented nearly orthogonal to the strikes of the major through-going faults. Slip along these secondary transverse features is predominantly left-lateral and is consistent with the reactivation of conjugate faults by the current regional stress field. Near the intersection of the San Jacinto and San Andreas faults, however, these active left-lateral faults appear to define a set of small crustal blocks, which in conjunction with both normal and reverse faulting earthquakes, suggests contemporary clockwise rotation as a result of regional right-lateral shear. Other left-lateral faults representing additional rotating block systems are identified in adjacent areas from geologic and seismologic data. Many of these structures predate the modern San Andreas system and may control the pattern of strain accumulation in southern California. Geodetic and paleomagnetic evidence confirm that block rotation by strike-slip faulting is nearly ubiquitous, particularly in areas where shear is distributed, and that it accommodates both short-term elastic and long-term nonelastic strain. A rotating block model accounts for a number of structural styles characteristic of strike-slip deformation in California, including: variable slip rates and alternating transtensional and transpressional features observed along strike of major wrench faults; domains of evenly-spaced antithetic faults that terminate against major fault boundaries; continued development of bends in faults with large lateral displacements; anomalous focal mechanisms; and differential uplift in areas otherwise expected to experience extension and subsidence. Since block rotation requires a detachment surface at depth to permit rotational movement, low-angle structures like detachments, of either local or regional extent, may be involved in the contemporary strike

Photomosaics and event evidence from the Frazier Mountain paleoseismic site, trench 1, cuts 1–4, San Andreas Fault Zone, southern California (2007–2009)

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Scharer, Katherine M.; Fumal, Tom E.; Weldon, Ray J.; Streig, Ashley R.

2014-01-01

The Frazier Mountain paleoseismic site is located at the northwest end of the Mojave section of the San Andreas Fault, in a small, closed depression at the base of Frazier Mountain near Tejon Pass, California (lat 34.8122° N., long 118.9034° W.). The site was known to contain a good record of earthquakes due to previous excavations by Lindvall and others (2002). This report provides data resulting from four nested excavations, or cuts, along trench 1 (T1) in 2007 and 2009 at the Frazier Mountain site. The four cuts were excavated progressively deeper and wider in an orientation perpendicular to the San Andreas Fault, exposing distal fan and marsh sediments deposited since ca. A.D. 1200. The results of the trenching show that earthquakes that ruptured the site have repeatedly produced a small depression or sag on the surface, which is subsequently infilled with sand and silt deposits. This report provides high-resolution photomosaics and logs for the T1 cuts, a detailed stratigraphic column for the deposits, and a table summarizing all of the evidence for ground rupturing paleoearthquakes logged in the trenches.

EFFECTS OF THE 1983 COALINGA, CALIFORNIA, EARTHQUAKE ONCREEP ALONG THE SAN ADREAS FAULT.

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Mavko, Gerald M.; Schulz, Sandra; Brown, Beth D.

1985-01-01

The M//L approximately equals 6. 5 earthquake that occurred near Coalinga, California, on May 2, 1983 induced changes in near-surface fault slip along the San Andreas fault. Coseismic steps were observed by creepmeters along a 200-km section of the San Andreas. some of the larger aftershocks induced additional steps, both right-lateral and left-lateral, and in general the sequence disrupted observed creep at several sites from preseismic long-term patterns. Static dislocation models can approximately explain the magnitudes and distribution of the larger coseismic steps on May 2. The smaller, more distant steps appear to be the abrupt release of accumulated slip, triggered by the coseismic strain changes, but independent of the strain change amplitudes.

Ground-rupturing earthquakes on the northern Big Bend of the San Andreas Fault, California, 800 A.D. to Present

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Scharer, Katherine M.; Weldon, Ray; Biasi, Glenn; Streig, Ashley; Fumal, Thomas E.

2017-01-01

Paleoseismic data on the timing of ground-rupturing earthquakes constrain the recurrence behavior of active faults and can provide insight on the rupture history of a fault if earthquakes dated at neighboring sites overlap in age and are considered correlative. This study presents the evidence and ages for 11 earthquakes that occurred along the Big Bend section of the southern San Andreas Fault at the Frazier Mountain paleoseismic site. The most recent earthquake to rupture the site was the Mw7.7–7.9 Fort Tejon earthquake of 1857. We use over 30 trench excavations to document the structural and sedimentological evolution of a small pull-apart basin that has been repeatedly faulted and folded by ground-rupturing earthquakes. A sedimentation rate of 0.4 cm/yr and abundant organic material for radiocarbon dating contribute to a record that is considered complete since 800 A.D. and includes 10 paleoearthquakes. Earthquakes have ruptured this location on average every ~100 years over the last 1200 years, but individual intervals range from ~22 to 186 years. The coefficient of variation of the length of time between earthquakes (0.7) indicates quasiperiodic behavior, similar to other sites along the southern San Andreas Fault. Comparison with the earthquake chronology at neighboring sites along the fault indicates that only one other 1857-size earthquake could have occurred since 1350 A.D., and since 800 A.D., the Big Bend and Mojave sections have ruptured together at most 50% of the time in Mw ≥ 7.3 earthquakes.

Late Quaternary slip history of the Mill Creek strand of the San Andreas fault in San Gorgonio Pass, southern California: The role of a subsidiary left-lateral fault in strand switching

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Kendrick, Katherine J.; Matti, Jonathan; Mahan, Shannon

2015-01-01

The fault history of the Mill Creek strand of the San Andreas fault (SAF) in the San Gorgonio Pass region, along with the reconstructed geomorphology surrounding this fault strand, reveals the important role of the left-lateral Pinto Mountain fault in the regional fault strand switching. The Mill Creek strand has 7.1–8.7 km total slip. Following this displacement, the Pinto Mountain fault offset the Mill Creek strand 1–1.25 km, as SAF slip transferred to the San Bernardino, Banning, and Garnet Hill strands. An alluvial complex within the Mission Creek watershed can be linked to palinspastic reconstruction of drainage segments to constrain slip history of the Mill Creek strand. We investigated surface remnants through detailed geologic mapping, morphometric and stratigraphic analysis, geochronology, and pedogenic analysis. The degree of soil development constrains the duration of surface stability when correlated to other regional, independently dated pedons. This correlation indicates that the oldest surfaces are significantly older than 500 ka. Luminescence dates of 106 ka and 95 ka from (respectively) 5 and 4 m beneath a younger fan surface are consistent with age estimates based on soil-profile development. Offset of the Mill Creek strand by the Pinto Mountain fault suggests a short-term slip rate of ∼10–12.5 mm/yr for the Pinto Mountain fault, and a lower long-term slip rate. Uplift of the Yucaipa Ridge block during the period of Mill Creek strand activity is consistent with thermochronologic modeled uplift estimates.

Southern San Andreas Fault Slip History Refined Using Pliocene Colorado River Deposits in the Western Salton Trough

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Dorsey, R. J.; Bennett, S. E. K.; Housen, B. A.

2016-12-01

Tectonic reconstructions of Pacific-North America plate motion in the Salton Trough region (Bennett et al., 2016) are constrained by: (1) late Miocene volcanic rocks that record 255 +/-10 km of transform offset across the northern Gulf of California since 6 Ma (average 42 mm/yr; Oskin and Stock, 2003); and (2) GPS data that show modern rates of 50-52 mm/yr between Pacific and North America plates, and 46-48 mm/yr between Baja California (BC) and North America (NAM) (Plattner et al., 2007). New data from Pliocene Colorado River deposits in the Salton Trough provide an important additional constraint on the geologic history of slip on the southern San Andreas Fault (SAF). The Arroyo Diablo Formation (ADF) in the San Felipe Hills SW of the Salton Sea contains abundant cross-bedded channel sandstones deformed in the dextral Clark fault zone. The ADF ranges in age from 4.3 to 2.8 Ma in the Fish Creek-Vallecito basin, and in the Borrego Badlands its upper contact with the Borrego Formation is 2.9 Ma based on our new magnetostratigraphy. ADF paleocurrent data from a 20-km wide, NW-oriented belt near Salton City record overall transport to the SW (corrected for bedding dip, N=165), with directions ranging from NW to SE. Spatial domain analysis reveals radial divergence of paleoflow to the: W and NW in the NW domain; SW in the central domain; and S in the SE domain. Data near Borrego Sink, which restores to south of Salton City after removing offset on the San Jacinto fault zone, show overall transport to the SE. Pliocene patterns of radial paleoflow divergence strongly resemble downstream bifurcation of fluvial distributary channels on the modern Colorado River delta SW of Yuma, and indicate that Salton City has translated 120-130 km NW along the SAF since 3 Ma. We propose a model in which post-6 Ma BC-NAM relative motion gradually accelerated to 50 mm/yr by 4 Ma, continued at 50 mm/yr from 4-1 Ma, and decreased to 46 mm/yr from 1-0 Ma (split equally between the SAF and

Break of slope in earthquake size distribution and creep rate along the San Andreas Fault system

Science.gov (United States)

Shebalin, P.; Narteau, C.; Vorobieva, I.

2017-12-01

Crustal faults accommodate slip either by a succession of earthquakes or continuous slip, andin most instances, both these seismic and aseismic processes coexist. Recorded seismicity and geodeticmeasurements are therefore two complementary data sets that together document ongoing deformationalong active tectonic structures. Here we study the influence of stable sliding on earthquake statistics.We show that creep along the San Andreas Fault is responsible for a break of slope in the earthquake sizedistribution. This slope increases with an increasing creep rate for larger magnitude ranges, whereas itshows no systematic dependence on creep rate for smaller magnitude ranges. This is interpreted as a deficitof large events under conditions of faster creep where seismic ruptures are less likely to propagate. Theseresults suggest that the earthquake size distribution does not only depend on the level of stress but also onthe type of deformation.

A 15 year catalog of more than 1 million low-frequency earthquakes: Tracking tremor and slip along the deep San Andreas Fault

Science.gov (United States)

Shelly, David R.

2017-05-01

Low-frequency earthquakes (LFEs) are small, rapidly recurring slip events that occur on the deep extensions of some major faults. Their collective activation is often observed as a semicontinuous signal known as tectonic (or nonvolcanic) tremor. This manuscript presents a catalog of more than 1 million LFEs detected along the central San Andreas Fault from 2001 to 2016. These events have been detected via a multichannel matched-filter search, cross-correlating waveform templates representing 88 different LFE families with continuous seismic data. Together, these source locations span nearly 150 km along the central San Andreas Fault, ranging in depth from 16 to 30 km. This accumulating catalog has been the source for numerous studies examining the behavior of these LFE sources and the inferred slip behavior of the deep fault. The relatively high temporal and spatial resolutions of the catalog have provided new insights into properties such as tremor migration, recurrence, and triggering by static and dynamic stress perturbations. Collectively, these characteristics are inferred to reflect a very weak fault likely under near-lithostatic fluid pressure, yet the physical processes controlling the stuttering rupture observed as tremor and LFE signals remain poorly understood. This paper aims to document the LFE catalog assembly process and associated caveats, while also updating earlier observations and inferred physical constraints. The catalog itself accompanies this manuscript as part of the electronic supplement, with the goal of providing a useful resource for continued future investigations.

Slip deficit on the san andreas fault at parkfield, california, as revealed by inversion of geodetic data.

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Segall, P; Harris, R

1986-09-26

A network of geodetic lines spanning the San Andreas fault near the rupture zone of the 1966 Parkfield, California, earthquake (magnitude M = 6) has been repeatedly surveyed since 1959. In the study reported here the average rates of line-length change since 1966 were inverted to determine the distribution of interseismic slip rate on the fault. These results indicate that the Parkfield rupture surface has not slipped significantly since 1966. Comparison of the geodetically determined seismic moment of the 1966 earthquake with the interseismic slip-deficit rate suggests that the strain released by the latest shock will most likely be restored between 1984 and 1989, although this may not occur until 1995. These results lend independent support to the earlier forecast of an M = 6 earthquake near Parkfield within 5 years of 1988.

Perspective view, Landsat overlay San Andreas Fault, Palmdale, California

Science.gov (United States)

2000-01-01

The prominent linear feature straight down the center of this perspective view is the San Andreas Fault. This segment of the fault lies near the city of Palmdale, California (the flat area in the right half of the image) about 60 kilometers (37 miles) north of Los Angeles. The fault is the active tectonic boundary between the North American plate on the right, and the Pacific plate on the left. Relative to each other, the Pacific plate is moving away from the viewer and the North American plate is moving toward the viewer along what geologists call a right lateral strike-slip fault. Two large mountain ranges are visible, the San Gabriel Mountains on the left and the Tehachapi Mountains in the upper right. The Lake Palmdale Reservoir, approximately 1.5 kilometers (0.9 miles) across, sits in the topographic depression created by past movement along the fault. Highway 14 is the prominent linear feature starting at the lower left edge of the image and continuing along the far side of the reservoir. The patterns of residential and agricultural development around Palmdale are seen in the Landsat imagery in the right half of the image. SRTM topographic data will be used by geologists studying fault dynamics and landforms resulting from active tectonics.This type of display adds the important dimension of elevation to the study of land use and environmental processes as observed in satellite images. The perspective view was created by draping a Landsat satellite image over an SRTM elevation model. Topography is exaggerated 1.5 times vertically. The Landsat image was provided by the United States Geological Survey's Earth Resources Observations Systems (EROS) Data Center, Sioux Falls, South Dakota.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (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

Precise tremor source locations and amplitude variations along the lower-crustal central San Andreas Fault

Science.gov (United States)

Shelly, David R.; Hardebeck, Jeanne L.

2010-01-01

We precisely locate 88 tremor families along the central San Andreas Fault using a 3D velocity model and numerous P and S wave arrival times estimated from seismogram stacks of up to 400 events per tremor family. Maximum tremor amplitudes vary along the fault by at least a factor of 7, with by far the strongest sources along a 25 km section of the fault southeast of Parkfield. We also identify many weaker tremor families, which have largely escaped prior detection. Together, these sources extend 150 km along the fault, beneath creeping, transitional, and locked sections of the upper crustal fault. Depths are mostly between 18 and 28 km, in the lower crust. Epicenters are concentrated within 3 km of the surface trace, implying a nearly vertical fault. A prominent gap in detectible activity is located directly beneath the region of maximum slip in the 2004 magnitude 6.0 Parkfield earthquake.

Does paleoseismology forecast the historic rates of large earthquakes on the San Andreas fault system?

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Biasi, Glenn; Scharer, Katherine M.; Weldon, Ray; Dawson, Timothy E.

2016-01-01

The 98-year open interval since the most recent ground-rupturing earthquake in the greater San Andreas boundary fault system would not be predicted by the quasi-periodic recurrence statistics from paleoseismic data. We examine whether the current hiatus could be explained by uncertainties in earthquake dating. Using seven independent paleoseismic records, 100 year intervals may have occurred circa 1150, 1400, and 1700 AD, but they occur in a third or less of sample records drawn at random. A second method sampling from dates conditioned on the existence of a gap of varying length suggests century-long gaps occur 3-10% of the time. A combined record with more sites would lead to lower probabilities. Systematic data over-interpretation is considered an unlikely explanation. Instead some form of non-stationary behaviour seems required, perhaps through long-range fault interaction. Earthquake occurrence since 1000 AD is not inconsistent with long-term cyclicity suggested from long runs of earthquake simulators.

Analysis of regional deformation and strain accumulation data adjacent to the San Andreas fault

Science.gov (United States)

Turcotte, Donald L.

1991-01-01

A new approach to the understanding of crustal deformation was developed under this grant. This approach combined aspects of fractals, chaos, and self-organized criticality to provide a comprehensive theory for deformation on distributed faults. It is hypothesized that crustal deformation is an example of comminution: Deformation takes place on a fractal distribution of faults resulting in a fractal distribution of seismicity. Our primary effort under this grant was devoted to developing an understanding of distributed deformation in the continental crust. An initial effort was carried out on the fractal clustering of earthquakes in time. It was shown that earthquakes do not obey random Poisson statistics, but can be approximated in many cases by coupled, scale-invariant fractal statistics. We applied our approach to the statistics of earthquakes in the New Hebrides region of the southwest Pacific because of the very high level of seismicity there. This work was written up and published in the Bulletin of the Seismological Society of America. This approach was also applied to the statistics of the seismicity on the San Andreas fault system.

San Francisco folio, California, Tamalpais, San Francisco, Concord, San Mateo, and Haywards quadrangles

Science.gov (United States)

Lawson, Andrew Cowper

1914-01-01

The five sheets of the San Francisco folio the Tamalpais, Ban Francisco, Concord, Ban Mateo, and Haywards sheets map a territory lying between latitude 37° 30' and 38° and longitude 122° and 122° 45'. Large parts of four of these sheets cover the waters of the Bay of San Francisco or of the adjacent Pacific Ocean. (See fig. 1.) Within the area mapped are the cities of San Francisco, Oakland, Berkeley, Alameda, Ban Rafael, and San Mateo, and many smaller towns and villages. These cities, which have a population aggregating about 750,000, together form the largest and most important center of commercial and industrial activity on the west coast of the United States. The natural advantages afforded by a great harbor, where the railways from the east meet the ships from all ports of the world, have determined the site of a flourishing cosmopolitan, commercial city on the shores of San Francisco Bay. The bay is encircled by hilly and mountainous country diversified by fertile valley lands and divides the territory mapped into two rather contrasted parts, the western part being again divided by the Golden Gate. It will therefore be convenient to sketch the geographic features under four headings (1) the area east of San Francisco Bay; (2) the San Francisco Peninsula; (3) the Marin Peninsula; (4) San Francisco Bay. (See fig. 2.)

A deep crustal fluid channel into the San Andreas Fault system near Parkfield, California

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Becken, M.; Ritter, O.; Park, S.K.; Bedrosian, P.A.; Weckmann, U.; Weber, M.

2008-01-01

Magnetotelluric (MT) data from 66 sites along a 45-km-long profile across the San Andreas Fault (SAF) were inverted to obtain the 2-D electrical resistivity structure of the crust near the San Andreas Fault Observatory at Depth (SAFOD). The most intriguing feature of the resistivity model is a steeply dipping upper crustal high-conductivity zone flanking the seismically defined SAF to the NE, that widens into the lower crust and appears to be connected to a broad conductivity anomaly in the upper mantle. Hypothesis tests of the inversion model suggest that upper and lower crustal and upper-mantle anomalies may be interconnected. We speculate that the high conductivities are caused by fluids and may represent a deep-rooted channel for crustal and/or mantle fluid ascent. Based on the chemical analysis of well waters, it was previously suggested that fluids can enter the brittle regime of the SAF system from the lower crust and mantle. At high pressures, these fluids can contribute to fault-weakening at seismogenic depths. These geochemical studies predicted the existence of a deep fluid source and a permeable pathway through the crust. Our resistivity model images a conductive pathway, which penetrates the entire crust, in agreement with the geochemical interpretation. However, the resistivity model also shows that the upper crustal branch of the high-conductivity zone is located NE of the seismically defined SAF, suggesting that the SAF does not itself act as a major fluid pathway. This interpretation is supported by both, the location of the upper crustal high-conductivity zone and recent studies within the SAFOD main hole, which indicate that pore pressures within the core of the SAF zone are not anomalously high, that mantle-derived fluids are minor constituents to the fault-zone fluid composition and that both the volume of mantle fluids and the fluid pressure increase to the NE of the SAF. We further infer from the MT model that the resistive Salinian block

California State Waters Map Series: offshore of San Gregorio, California

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Cochrane, Guy R.; Dartnell, Peter; Greene, H. Gary; Watt, Janet T.; Golden, Nadine E.; Endris, Charles A.; Phillips, Eleyne L.; Hartwell, Stephen R.; Johnson, Samuel Y.; Kvitek, Rikk G.; Erdey, Mercedes D.; Bretz, Carrie K.; Manson, Michael W.; Sliter, Ray W.; Ross, Stephanie L.; Dieter, Bryan E.; Chin, John L.; Cochran, Susan A.; Cochrane, Guy R.; Cochran, Susan A.

2014-01-01

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California's State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Offshore of San Gregorio map area is located in northern California, on the Pacific coast of the San Francisco Peninsula about 50 kilometers south of the Golden Gate. The map area lies offshore of the Santa Cruz Mountains, part of the northwest-trending Coast Ranges that run roughly parallel to the San Andreas Fault Zone. The Santa Cruz Mountains lie between the San Andreas Fault Zone and the San Gregorio Fault system. The nearest significant onshore cultural centers in the map area are San Gregorio and Pescadero, both unincorporated communities with populations well under 1,000. Both communities are situated inland of state beaches that share their names. No harbor facilities are within the Offshore of San Gregorio map area. The hilly coastal area is virtually undeveloped grazing land for sheep and cattle. The coastal geomorphology is controlled by late Pleistocene and Holocene slip in the San Gregorio Fault system. A westward bend in the San Andreas Fault Zone, southeast of the map area, coupled with right-lateral movement along the San Gregorio Fault system have caused regional folding and uplift. The coastal area consists of high coastal bluffs and vertical sea cliffs. Coastal promontories in

Telegraph Canyon Creek, City of Chula Vista, San Diego County, California. Detailed Report for Flood Control. Volume 1. Main Report.

Science.gov (United States)

1983-07-01

SECURITY CLASS. (of chi* report) Los Angeles District, Corps of Engineers Ucasfe P.O. Box 2711, Los Angeles, CA 90053 15&. DEL SI F1CATION/OWNGRAOI...greater potential for the possible occurrence of a large earthquake include the Whittier-Elsinore, Agua Caliente, San Jacinto, and the San Andreas...about 900,000 motor vehicles used within the county. 2.20 Air contaminants monitored within the San Diego Bay air basin include carbon monoxide (CO

A new perspective on the geometry of the San Andreas Fault in southern California and its relationship to lithospheric structure

Science.gov (United States)

Fuis, Gary S.; Scheirer, Daniel S.; Langenheim, Victoria; Kohler, Monica D.

2012-01-01

The widely held perception that the San Andreas fault (SAF) is vertical or steeply dipping in most places in southern California may not be correct. From studies of potential‐field data, active‐source imaging, and seismicity, the dip of the SAF is significantly nonvertical in many locations. The direction of dip appears to change in a systematic way through the Transverse Ranges: moderately southwest (55°–75°) in the western bend of the SAF in the Transverse Ranges (Big Bend); vertical to steep in the Mojave Desert; and moderately northeast (37°–65°) in a region extending from San Bernardino to the Salton Sea, spanning the eastern bend of the SAF in the Transverse Ranges. The shape of the modeled SAF is crudely that of a propeller. If confirmed by further studies, the geometry of the modeled SAF would have important implications for tectonics and strong ground motions from SAF earthquakes. The SAF can be traced or projected through the crust to the north side of a well documented high‐velocity body (HVB) in the upper mantle beneath the Transverse Ranges. The north side of this HVB may be an extension of the plate boundary into the mantle, and the HVB would appear to be part of the Pacific plate.

Slip rates and spatially variable creep on faults of the northern San Andreas system inferred through Bayesian inversion of Global Positioning System data

Science.gov (United States)

Murray, Jessica R.; Minson, Sarah E.; Svarc, Jerry L.

2014-01-01

Fault creep, depending on its rate and spatial extent, is thought to reduce earthquake hazard by releasing tectonic strain aseismically. We use Bayesian inversion and a newly expanded GPS data set to infer the deep slip rates below assigned locking depths on the San Andreas, Maacama, and Bartlett Springs Faults of Northern California and, for the latter two, the spatially variable interseismic creep rate above the locking depth. We estimate deep slip rates of 21.5 ± 0.5, 13.1 ± 0.8, and 7.5 ± 0.7 mm/yr below 16 km, 9 km, and 13 km on the San Andreas, Maacama, and Bartlett Springs Faults, respectively. We infer that on average the Bartlett Springs fault creeps from the Earth's surface to 13 km depth, and below 5 km the creep rate approaches the deep slip rate. This implies that microseismicity may extend below the locking depth; however, we cannot rule out the presence of locked patches in the seismogenic zone that could generate moderate earthquakes. Our estimated Maacama creep rate, while comparable to the inferred deep slip rate at the Earth's surface, decreases with depth, implying a slip deficit exists. The Maacama deep slip rate estimate, 13.1 mm/yr, exceeds long-term geologic slip rate estimates, perhaps due to distributed off-fault strain or the presence of multiple active fault strands. While our creep rate estimates are relatively insensitive to choice of model locking depth, insufficient independent information regarding locking depths is a source of epistemic uncertainty that impacts deep slip rate estimates.

Relating seismicity to the velocity structure of the San Andreas Fault near Parkfield, CA

Science.gov (United States)

Lippoldt, Rachel; Porritt, Robert W.; Sammis, Charles G.

2017-06-01

The central section of the San Andreas Fault (SAF) displays a range of seismic phenomena including normal earthquakes, low-frequency earthquakes (LFE), repeating microearthquakes (REQ) and aseismic creep. Although many lines of evidence suggest that LFEs are tied to the presence of fluids, their geological setting is still poorly understood. Here, we map the seismic velocity structures associated with LFEs beneath the central SAF using surface wave tomography from ambient seismic noise to provide constraints on the physical conditions that control LFE occurrence. Fault perpendicular sections show that the SAF, as revealed by lateral contrasts in relative velocities, is contiguous to depths of 50 km and appears to be relatively localized at depths between about 15 and 30 km. This is consistent with the hypothesis that LFEs are shear-slip events on a deep extension of the SAF. We find that along strike variations in seismic behaviour correspond to changes in the seismic structure, which support proposed connections between fluids and seismicity. LFEs and REQs occur within low-velocity structures, suggesting that the presence of fluids, weaker minerals, or hydrous phase minerals may play an important role in the generation of slow-slip phenomena.

75 FR 38412 - Safety Zone; San Diego POPS Fireworks, San Diego, CA

Science.gov (United States)

2010-07-02

...-AA00 Safety Zone; San Diego POPS Fireworks, San Diego, CA AGENCY: Coast Guard, DHS. ACTION: Temporary... waters of San Diego Bay in support of the San Diego POPS Fireworks. This safety zone is necessary to... San Diego POPS Fireworks, which will include fireworks presentations conducted from a barge in San...

Origin and spatial distribution of gas at seismogenic depths of the San Andreas Fault from drill-mud gas analysis

International Nuclear Information System (INIS)

Wiersberg, Thomas; Erzinger, Joerg

2008-01-01

Data are presented on the molecular composition of drill-mud gas from the lower sedimentary section (1800-3987 m) of the SAFOD (San Andreas Fault Observatory at Depth) Main Hole measured on-line during drilling, as well as C and H isotope data from off-line mud gas samples. Hydrocarbons, H 2 and CO 2 are the most abundant non-atmospheric gases in drill-mud when drilling seismogenic zones. Gas influx into the well at depth is related to the lithology and permeability of the drilled strata: larger formation gas influx was detected when drilling through organic-rich shales and permeable sandstones. The SAF (San Andreas Fault), encountered between approximately 3100 m and 3450 m borehole depth, is generally low in gas, but is encompassed by two gas-rich zones (2700-2900 m and below 3550 m) at the fault margins with enhanced 222 Rn activities and distinct gas compositions. Within the fault, two interstratified gas-rich lenses (3150-3200 m and 3310-3340 m) consist of CO 2 and hydrocarbons (upper zone), but almost exclusively of hydrocarbons (lower zone). The isotopic composition indicates an organic source of hydrocarbons and CO 2 in the entire sedimentary section of the well. Hydrocarbons in sedimentary strata are partly of microbial origin down to ∼2500 m borehole depth. The contribution of thermogenic gas increases between ∼2500 m and 3200 m. Below ∼3200 m, hydrocarbons fully derive from thermal degradation of organic matter. The lack of H 2 in the center of the fault and the high concentration of H 2 in the fractured zones at the fault margins are consistent with H 2 formation by interaction of water with fresh silica mineral surfaces generated by tectonic activities, however, this needs to be verified by laboratory experiments. Based on these studies, it is concluded that the fault zone margins consist of strata with enhanced permeability, separated by a low-permeability fault center

Photomosaics and event evidence from the Frazier Mountain paleoseismic site, trench 1, cuts 5–24, San Andreas Fault Zone, southern California (2010–2012)

Science.gov (United States)

Scharer, Katherine M.; Fumal, Tom E.; Weldon, Ray J.; Streig, Ashley R.

2015-08-24

The Frazier Mountain paleoseismic site is located within the northern Big Bend of the southern San Andreas Fault (lat 34.8122° N., lon 118.9034° W.), in a small structural basin formed by the fault (fig. 1). The site has been the focus of over a decade of paleoseismic study due to high stratigraphic resolution and abundant dateable material. Trench 1 (T1) was initially excavated as a 50-m long, fault-perpendicular trench crossing the northern half of the basin (Lindvall and others, 2002; Scharer and others, 2014a). Owing to the importance of a high-resolution trench site at this location on a 200-km length of the fault with no other long paleoseismic records, later work progressively lengthened and deepened T1 in a series of excavations, or cuts, that enlarged the original excavation. Scharer and others (2014a) provide the photomosaics and event evidence for the first four cuts, which largely show the upper section of the site, represented by alluvial deposits that date from about A.D. 1500 to present. Scharer and others (2014b) discuss the earthquake evidence and dating at the site within the context of prehistoric rupture lengths and magnitudes on the southern San Andreas Fault. Here we present the photomosaics and event evidence for a series of cuts from the lower section, covering sediments that were deposited from about A.D. 500 to 1500 (fig. 2).

Locating Very-Low-Frequency Earthquakes in the San Andreas Fault.

Science.gov (United States)

Peña-Castro, A. F.; Harrington, R. M.; Cochran, E. S.

2016-12-01

The portion of tectonic fault where rheological properties transtition from brittle to ductile hosts a variety of seismic signals suggesting a range of slip velocities. In subduction zones, the two dominantly observed seismic signals include very-low frequency earthquakes ( VLFEs), and low-frequency earthquakes (LFEs) or tectonic tremor. Tremor and LFE are also commonly observed in transform faults, however, VLFEs have been reported dominantly in subduction zone environments. Here we show some of the first known observations of VLFEs occurring on a plate boundary transform fault, the San Andreas Fault (SAF) between the Cholame-Parkfield segment in California. We detect VLFEs using both permanent and temporary stations in 2010-2011 within approximately 70 km of Cholame, California. We search continous waveforms filtered from 0.02-0.05 Hz, and remove time windows containing teleseismic events and local earthquakes, as identified in the global Centroid Moment Tensor (CMT) and the Northern California Seismic Network (NCSN) catalog. We estimate the VLFE locations by converting the signal into envelopes, and cross-correlating them for phase-picking, similar to procedures used for locating tectonic tremor. We first perform epicentral location using a grid search method and estimate a hypocenter location using Hypoinverse and a shear-wave velocity model when the epicenter is located close to the SAF trace. We account for the velocity contrast across the fault using separate 1D velocity models for stations on each side. Estimated hypocentral VLFE depths are similar to tremor catalog depths ( 15-30 km). Only a few VLFEs produced robust hypocentral locations, presumably due to the difficulty in picking accurate phase arrivals with such a low-frequency signal. However, for events for which no location could be obtained, the moveout of phase arrivals across the stations were similar in character, suggesting that other observed VLFEs occurred in close proximity.

Ground motion modeling of the 1906 San Francisco earthquake II: Ground motion estimates for the 1906 earthquake and scenario events

Energy Technology Data Exchange (ETDEWEB)

Aagaard, B; Brocher, T; Dreger, D; Frankel, A; Graves, R; Harmsen, S; Hartzell, S; Larsen, S; McCandless, K; Nilsson, S; Petersson, N A; Rodgers, A; Sjogreen, B; Tkalcic, H; Zoback, M L

2007-02-09

We estimate the ground motions produced by the 1906 San Francisco earthquake making use of the recently developed Song et al. (2008) source model that combines the available geodetic and seismic observations and recently constructed 3D geologic and seismic velocity models. Our estimates of the ground motions for the 1906 earthquake are consistent across five ground-motion modeling groups employing different wave propagation codes and simulation domains. The simulations successfully reproduce the main features of the Boatwright and Bundock (2005) ShakeMap, but tend to over predict the intensity of shaking by 0.1-0.5 modified Mercalli intensity (MMI) units. Velocity waveforms at sites throughout the San Francisco Bay Area exhibit characteristics consistent with rupture directivity, local geologic conditions (e.g., sedimentary basins), and the large size of the event (e.g., durations of strong shaking lasting tens of seconds). We also compute ground motions for seven hypothetical scenarios rupturing the same extent of the northern San Andreas fault, considering three additional hypocenters and an additional, random distribution of slip. Rupture directivity exerts the strongest influence on the variations in shaking, although sedimentary basins do consistently contribute to the response in some locations, such as Santa Rosa, Livermore, and San Jose. These scenarios suggest that future large earthquakes on the northern San Andreas fault may subject the current San Francisco Bay urban area to stronger shaking than a repeat of the 1906 earthquake. Ruptures propagating southward towards San Francisco appear to expose more of the urban area to a given intensity level than do ruptures propagating northward.

Locating non-volcanic tremor along the San Andreas Fault using a multiple array source imaging technique

Science.gov (United States)

Ryberg, T.; Haberland, C.H.; Fuis, G.S.; Ellsworth, W.L.; Shelly, D.R.

2010-01-01

Non-volcanic tremor (NVT) has been observed at several subduction zones and at the San Andreas Fault (SAF). Tremor locations are commonly derived by cross-correlating envelope-transformed seismic traces in combination with source-scanning techniques. Recently, they have also been located by using relative relocations with master events, that is low-frequency earthquakes that are part of the tremor; locations are derived by conventional traveltime-based methods. Here we present a method to locate the sources of NVT using an imaging approach for multiple array data. The performance of the method is checked with synthetic tests and the relocation of earthquakes. We also applied the method to tremor occurring near Cholame, California. A set of small-aperture arrays (i.e. an array consisting of arrays) installed around Cholame provided the data set for this study. We observed several tremor episodes and located tremor sources in the vicinity of SAF. During individual tremor episodes, we observed a systematic change of source location, indicating rapid migration of the tremor source along SAF. ?? 2010 The Authors Geophysical Journal International ?? 2010 RAS.

78 FR 19103 - Safety Zone; Spanish Navy School Ship San Sebastian El Cano Escort; Bahia de San Juan; San Juan, PR

Science.gov (United States)

2013-03-29

...-AA00 Safety Zone; Spanish Navy School Ship San Sebastian El Cano Escort; Bahia de San Juan; San Juan... temporary moving safety zone on the waters of Bahia de San Juan during the transit of the Spanish Navy... Channel entrance, and to protect the high ranking officials on board the Spanish Navy School Ship San...

Ground-motion modeling of the 1906 San Francisco Earthquake, part II: Ground-motion estimates for the 1906 earthquake and scenario events

Science.gov (United States)

Aagaard, Brad T.; Brocher, T.M.; Dolenc, D.; Dreger, D.; Graves, R.W.; Harmsen, S.; Hartzell, S.; Larsen, S.; McCandless, K.; Nilsson, S.; Petersson, N.A.; Rodgers, A.; Sjogreen, B.; Zoback, M.L.

2008-01-01

We estimate the ground motions produce by the 1906 San Francisco earthquake making use of the recently developed Song et al. (2008) source model that combines the available geodetic and seismic observations and recently constructed 3D geologic and seismic velocity models. Our estimates of the ground motions for the 1906 earthquake are consistent across five ground-motion modeling groups employing different wave propagation codes and simulation domains. The simulations successfully reproduce the main features of the Boatwright and Bundock (2005) ShakeMap, but tend to over predict the intensity of shaking by 0.1-0.5 modified Mercalli intensity (MMI) units. Velocity waveforms at sites throughout the San Francisco Bay Area exhibit characteristics consistent with rupture directivity, local geologic conditions (e.g., sedimentary basins), and the large size of the event (e.g., durations of strong shaking lasting tens of seconds). We also compute ground motions for seven hypothetical scenarios rupturing the same extent of the northern San Andreas fault, considering three additional hypocenters and an additional, random distribution of slip. Rupture directivity exerts the strongest influence on the variations in shaking, although sedimentary basins do consistently contribute to the response in some locations, such as Santa Rosa, Livermore, and San Jose. These scenarios suggest that future large earthquakes on the northern San Andreas fault may subject the current San Francisco Bay urban area to stronger shaking than a repeat of the 1906 earthquake. Ruptures propagating southward towards San Francisco appear to expose more of the urban area to a given intensity level than do ruptures propagating northward.

Compact High Resolution SANS using very cold neutrons (VCN-SANS)

International Nuclear Information System (INIS)

Kennedy, S.; Yamada, M.; Iwashita, Y.; Geltenbort, P.; Bleuel, M.; Shimizu, H.

2011-01-01

SANS (Small Angle Neutron Scattering) is a popular method for elucidation of nano-scale structures. However science continually challenges SANS for higher performance, prompting exploration of ever-more exotic and expensive technologies. We propose a compact high resolution SANS, using very cold neutrons, magnetic focusing lens and a wide-angle spherical detector. This system will compete with modern 40 m pinhole SANS in one tenth of the length, matching minimum Q, Q-resolution and dynamic range. It will also probe dynamics using the MIEZE method. Our prototype lens (a rotating permanent-magnet sextupole), focuses a pulsed neutron beam over 3-5 nm wavelength and has measured SANS from micelles and polymer blends. (authors)

Paleoearthquakes at Frazier Mountain, California delimit extent and frequency of past San Andreas Fault ruptures along 1857 trace

Science.gov (United States)

Scharer, Katherine M.; Weldon, Ray; Streig, Ashley; Fumal, Thomas

2014-01-01

Large earthquakes are infrequent along a single fault, and therefore historic, well-characterized earthquakes exert a strong influence on fault behavior models. This is true of the 1857 Fort Tejon earthquake (estimated M7.7–7.9) on the southern San Andreas Fault (SSAF), but an outstanding question is whether the 330 km long rupture was typical. New paleoseismic data for six to seven ground-rupturing earthquakes on the Big Bend of the SSAF restrict the pattern of possible ruptures on the 1857 stretch of the fault. In conjunction with existing sites, we show that over the last ~650 years, at least 75% of the surface ruptures are shorter than the 1857 earthquake, with estimated rupture lengths of 100 to <300 km. These results suggest that the 1857 rupture was unusual, perhaps leading to the long open interval, and that a return to pre-1857 behavior would increase the rate of M7.3–M7.7 earthquakes.

76 FR 45693 - Safety Zone; San Diego POPS Fireworks, San Diego, CA

Science.gov (United States)

2011-08-01

...-AA00 Safety Zone; San Diego POPS Fireworks, San Diego, CA AGENCY: Coast Guard, DHS. ACTION: Temporary... San Diego Bay in support of the San Diego POPS Fireworks. This safety zone is necessary to provide for... of the waterway during scheduled fireworks events. Persons and vessels will be prohibited from...

Implications of Microstructural Studies of the SAFOD Gouge for the Strength and Deformation Mechanisms in the Creeping Segment of the San Andreas Fault

Science.gov (United States)

Hadizadeh, J.; Gratier, J. L.; Mittempergher, S.; Renard, F.; Richard, J.; di Toro, G.; Babaie, H. A.

2010-12-01

The San Andreas Fault zone (SAF) in the vicinity of the San Andreas Fault Observatory at Depth (SAFOD)in central California is characterized by an average 21 mm/year aseismic creep and strain release through repeating Mmicroscopy, cathodoluminescence imaging, X-ray fluorescence mapping, and energy dispersive X-ray spectroscopy. The microstructural and analytical data suggest that deformation is by a coupling of cataclastic flow and pressure solution accompanied by widespread alteration of feldspar to clay minerals and other neomineralizations. The clay contents of the gouge and streaks of serpentinite are not uniformly distributed, but weakness of the creeping segment is likely to be due to intrinsically low frictional strength of the fault material. This conclusion, which is based on the overall ratio of clay/non-clay constituents and the presence of talc in the actively deforming zones, is consistent with the 0.3-0.45 coefficient of friction for the drill cuttings tested by others. We also considered weakening by diffusion-accommodated grain boundary sliding. There are two main trends in the microstructural data that provide a basis for explaining the creep rate and seismic activity: 1. Clay content of the gouge including serpentinite and talc increases toward the 1-3m wide borehole casing deformation zones, which are expected to be deforming at above the average creep rate 2. Evidence of pressure solution creep and fracture sealing is more abundant in the siltstone cataclasites than in the shale. Such rocks could act as rigid inclusions that are repeatedly loaded to seismic failure by creep of the surrounding clay gouge. Regular cycles of fracture and restrengthening by fracture sealing in and around the inclusions are thus expected. The inclusions may be viewed as asperity patches (or cluster of patches) that predominantly deform by pressure solution at below the average creep rate.

33 CFR 165.754 - Safety Zone: San Juan Harbor, San Juan, PR.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Safety Zone: San Juan Harbor, San Juan, PR. 165.754 Section 165.754 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Zone: San Juan Harbor, San Juan, PR. (a) Regulated area. A moving safety zone is established in the...

Monitoring of crustal movements in the San Andreas fault zone by a satellite-borne ranging system. Ph.D. Thesis

Science.gov (United States)

Kumar, M.

1976-01-01

The Close Grid Geodynamic Measurement System is conceived as an orbiting ranging device with a ground base grid of reflectors or transponders (spacing 1.0 to 30 km), which are projected to be of low cost (maintenance free and unattended), and which will permit the saturation of a local area to obtain data useful to monitor crustal movements in the San Andreas fault zone. The system includes a station network of 75 stations covering an area between 36 deg N and 38 deg N latitudes, and 237 deg E and 239 deg E longitudes, with roughly half of the stations on either side of the faults. In addition, the simulation of crustal movements through the introduction of changes in the relative positions between grid stations, weather effect for intervisibility between satellite and station and loss of observations thereof, and comparative evaluation of various observational scheme-patterns have been critically studied.

Using surface creep rate to infer fraction locked for sections of the San Andreas fault system in northern California from alignment array and GPS data

Science.gov (United States)

Lienkaemper, James J.; McFarland, Forrest S.; Simpson, Robert W.; Caskey, S. John

2014-01-01

Surface creep rate, observed along five branches of the dextral San Andreas fault system in northern California, varies considerably from one section to the next, indicating that so too may the depth at which the faults are locked. We model locking on 29 fault sections using each section’s mean long‐term creep rate and the consensus values of fault width and geologic slip rate. Surface creep rate observations from 111 short‐range alignment and trilateration arrays and 48 near‐fault, Global Positioning System station pairs are used to estimate depth of creep, assuming an elastic half‐space model and adjusting depth of creep iteratively by trial and error to match the creep observations along fault sections. Fault sections are delineated either by geometric discontinuities between them or by distinctly different creeping behaviors. We remove transient rate changes associated with five large (M≥5.5) regional earthquakes. Estimates of fraction locked, the ratio of moment accumulation rate to loading rate, on each section of the fault system provide a uniform means to inform source parameters relevant to seismic‐hazard assessment. From its mean creep rates, we infer the main branch (the San Andreas fault) ranges from only 20%±10% locked on its central creeping section to 99%–100% on the north coast. From mean accumulation rates, we infer that four urban faults appear to have accumulated enough seismic moment to produce major earthquakes: the northern Calaveras (M 6.8), Hayward (M 6.8), Rodgers Creek (M 7.1), and Green Valley (M 7.1). The latter three faults are nearing or past their mean recurrence interval.

Scientific drilling into the San Andreas fault and site characterization research: Planning and coordination efforts. Final technical report

Energy Technology Data Exchange (ETDEWEB)

Zoback, M.D.

1998-08-30

The fundamental scientific issue addressed in this proposal, obtaining an improved understanding of the physical and chemical processes responsible for earthquakes along major fault zones, is clearly of global scientific interest. By sampling the San Andreas fault zone and making direct measurements of fault zone properties to 4.0 km at Parkfield they will be studying an active plate-boundary fault at a depth where aseismic creep and small earthquakes occur and where a number of the scientific questions associated with deeper fault zone drilling can begin to be addressed. Also, the technological challenges associated with drilling, coring, downhole measurements and borehole instrumentation that may eventually have to be faced in deeper drilling can first be addressed at moderate depth and temperature in the Parkfield hole. Throughout the planning process leading to the development of this proposal they have invited participation by scientists from around the world. As a result, the workshops and meetings they have held for this project have involved about 350 scientists and engineers from about a dozen countries.

Using Low-Frequency Earthquake Families on the San Andreas Fault as Deep Creepmeters

Science.gov (United States)

Thomas, A. M.; Beeler, N. M.; Bletery, Q.; Burgmann, R.; Shelly, D. R.

2018-01-01

The central section of the San Andreas Fault hosts tectonic tremor and low-frequency earthquakes (LFEs) similar to subduction zone environments. LFEs are often interpreted as persistent regions that repeatedly fail during the aseismic shear of the surrounding fault allowing them to be used as creepmeters. We test this idea by using the recurrence intervals of individual LFEs within LFE families to estimate the timing, duration, recurrence interval, slip, and slip rate associated with inferred slow slip events. We formalize the definition of a creepmeter and determine whether this definition is consistent with our observations. We find that episodic families reflect surrounding creep over the interevent time, while the continuous families and the short time scale bursts that occur as part of the episodic families do not. However, when these families are evaluated on time scales longer than the interevent time these events can also be used to meter slip. A straightforward interpretation of episodic families is that they define sections of the fault where slip is distinctly episodic in well-defined slow slip events that slip 16 times the long-term rate. In contrast, the frequent short-term bursts of the continuous and short time scale episodic families likely do not represent individual creep events but rather are persistent asperities that are driven to failure by quasi-continuous creep on the surrounding fault. Finally, we find that the moment-duration scaling of our inferred creep events are inconsistent with the proposed linear moment-duration scaling. However, caution must be exercised when attempting to determine scaling with incomplete knowledge of scale.

Shallow soil CO2 flow along the San Andreas and Calaveras Faults, California

Science.gov (United States)

Lewicki, J.L.; Evans, William C.; Hilley, G.E.; Sorey, M.L.; Rogie, J.D.; Brantley, S.L.

2003-01-01

We evaluate a comprehensive soil CO2 survey along the San Andreas fault (SAF) in Parkfield, and the Calaveras fault (CF) in Hollister, California, in the context of spatial and temporal variability, origin, and transport of CO2 in fractured terrain. CO2 efflux was measured within grids with portable instrumentation and continously with meteorological parameters at a fixed station, in both faulted and unfaulted areas. Spatial and temporal variability of surface CO2 effluxes was observed to be higher at faulted SAF and CF sites, relative to comparable background areas. However, ??13C (-23.3 to - 16.4???) and ??14C (75.5 to 94.4???) values of soil CO2 in both faulted and unfaulted areas are indicative of biogenic CO2, even though CO2 effluxes in faulted areas reached values as high as 428 g m-2 d-1. Profiles of soil CO2 concentration as a function of depth were measured at multiple sites within SAF and CF grids and repeatedly at two locations at the SAF grid. Many of these profiles suggest a surprisingly high component of advective CO2 flow. Spectral and correlation analysis of SAF CO2 efflux and meteorological parameter time series indicates that effects of wind speed variations on atmospheric air flow though fractures modulate surface efflux of biogenic CO2. The resulting areal patterns in CO2 effluxes could be erroneously attributed to a deep gas source in the absence of isotopic data, a problem that must be addressed in fault zone soil gas studies.

Minería, conflicto y mediadores locales: Minera San Xavier en Cerro de San Pedro, México Mineira, conflito e mediadores locais: Minera San Xavier em Cerro de San Pedro Mining, conflict and local brokers: Minera San Xavier in Cerro de San Pedro

Directory of Open Access Journals (Sweden)

Hernán Horacio Schiaffini

2011-12-01

Full Text Available Este trabajo indaga en las instancias de mediación que intervienen en la articulación de procesos económicos de gran escala y su puesta en práctica local. Basándonos en el conflicto que se produjo en el Municipio de Cerro de San Pedro (San Luis Potosí, México entre la empresa Minera San Xavier y el Frente Amplio Opositor (FAO a la misma, aplicamos el método etnográfico con el objetivo de describir las estructuras locales de mediación política y analizar sus prácticas y racionalidad. Intentamos demostrar así la importancia de los factores políticos locales en las vinculaciones entre estado, empresa y población.Este trabalho indaga nas instâncias de mediação que intervêm em processos econômicos de grande escala e sua posta em prática local. Baseando-nos no conflito no Cerro de San Pedro (San Luis Potosí, México entre a empresa Minera San Xavier e a Frente Amplio Opositor (FAO aplicamos o método etnográfico pra descrever as estruturas de mediação política locais e analisar suas práticas e racionalidade. Tenta-se demonstrar assim a importância dos fatores políticos locais nas vinculações entre estado, empresa e população.This paper investigates in instances of mediation involved in large-scale economic processes and local implementation. Analyzing the conflict in Cerro de San Pedro (San Luis Potosí, México among San Xavier mining company and the Frente Amplio Opositor (FAO, it applies an ethnographic approach to describe the local structures of political mediation and its practices and rationality. The work shows the relevance of local factors in the relationships between State, company and people.

Understanding strain transfer and basin evolution complexities in the Salton pull-apart basin near the Southern San Andreas Fault

Science.gov (United States)

Kell, A. M.; Sahakian, V. J.; Kent, G. M.; Driscoll, N. W.; Harding, A. J.; Baskin, R. L.; Barth, M.; Hole, J. A.; Stock, J. M.; Fuis, G. S.

2015-12-01

Active source seismic data in the Salton Sea provide insight into the complexity of the pull-apart system development. Seismic reflection data combined with tomographic cross sections give constraints on the timing of basin development and strain partitioning between the two dominant dextral faults in the region; the Imperial fault to the southwest and the Southern San Andreas fault (SSAF) to the northeast. Deformation associated with this step-over appears young, having formed in the last 20-40 k.a. The complexity seen in the Salton Sea is similar to that seen in pull-apart basins worldwide. In the southern basin of the Salton Sea, a zone of transpression is noted near the southern termination of the San Andreas fault, though this stress regime quickly transitions to a region of transtension in the northern reaches of the sea. The evolution seen in the basin architecture is likely related to a transition of the SSAF dying to the north, and giving way to youthful segments of the Brawley seismic zone and Imperial fault. Stratigraphic signatures seen in seismic cross-sections also reveal a long-term component of slip to the southwest on a fault 1-2 km west of the northeastern Salton Sea shoreline. Numerous lines of evidence, including seismic reflection data, high-resolution bathymetry within the Salton Sea, and folding patterns in the Borrego Formation to the east of the sea support an assertion of a previously unmapped fault, the Salton Trough fault (STF), parallel to the SAF and just offshore within the Salton Sea. Seismic observations are seen consistently within two datasets of varying vertical resolutions, up to depths of 4-5 km, suggesting that this fault strand is much longer-lived than the evolution seen in the southern sub-basin. The existence of the STF unifies discrepancies between the onshore seismic studies and data collected within the sea. The STF likely serves as the current bounding fault to the active pull-apart system, as it aligns with the "rung

A microstructural study of fault rocks from the SAFOD: Implications for the deformation mechanisms and strength of the creeping segment of the San Andreas Fault

Science.gov (United States)

Hadizadeh, Jafar; Mittempergher, Silvia; Gratier, Jean-Pierre; Renard, Francois; Di Toro, Giulio; Richard, Julie; Babaie, Hassan A.

2012-09-01

The San Andreas Fault zone in central California accommodates tectonic strain by stable slip and microseismic activity. We study microstructural controls of strength and deformation in the fault using core samples provided by the San Andreas Fault Observatory at Depth (SAFOD) including gouge corresponding to presently active shearing intervals in the main borehole. The methods of study include high-resolution optical and electron microscopy, X-ray fluorescence mapping, X-ray powder diffraction, energy dispersive X-ray spectroscopy, white light interferometry, and image processing. The fault zone at the SAFOD site consists of a strongly deformed and foliated core zone that includes 2-3 m thick active shear zones, surrounded by less deformed rocks. Results suggest deformation and foliation of the core zone outside the active shear zones by alternating cataclasis and pressure solution mechanisms. The active shear zones, considered zones of large-scale shear localization, appear to be associated with an abundance of weak phases including smectite clays, serpentinite alteration products, and amorphous material. We suggest that deformation along the active shear zones is by a granular-type flow mechanism that involves frictional sliding of microlithons along phyllosilicate-rich Riedel shear surfaces as well as stress-driven diffusive mass transfer. The microstructural data may be interpreted to suggest that deformation in the active shear zones is strongly displacement-weakening. The fault creeps because the velocity strengthening weak gouge in the active shear zones is being sheared without strong restrengthening mechanisms such as cementation or fracture sealing. Possible mechanisms for the observed microseismicity in the creeping segment of the SAF include local high fluid pressure build-ups, hard asperity development by fracture-and-seal cycles, and stress build-up due to slip zone undulations.

Southern San Andreas Fault seismicity is consistent with the Gutenberg-Richter magnitude-frequency distribution

Science.gov (United States)

Page, Morgan T.; Felzer, Karen

2015-01-01

The magnitudes of any collection of earthquakes nucleating in a region are generally observed to follow the Gutenberg-Richter (G-R) distribution. On some major faults, however, paleoseismic rates are higher than a G-R extrapolation from the modern rate of small earthquakes would predict. This, along with other observations, led to formulation of the characteristic earthquake hypothesis, which holds that the rate of small to moderate earthquakes is permanently low on large faults relative to the large-earthquake rate (Wesnousky et al., 1983; Schwartz and Coppersmith, 1984). We examine the rate difference between recent small to moderate earthquakes on the southern San Andreas fault (SSAF) and the paleoseismic record, hypothesizing that the discrepancy can be explained as a rate change in time rather than a deviation from G-R statistics. We find that with reasonable assumptions, the rate changes necessary to bring the small and large earthquake rates into alignment agree with the size of rate changes seen in epidemic-type aftershock sequence (ETAS) modeling, where aftershock triggering of large earthquakes drives strong fluctuations in the seismicity rates for earthquakes of all magnitudes. The necessary rate changes are also comparable to rate changes observed for other faults worldwide. These results are consistent with paleoseismic observations of temporally clustered bursts of large earthquakes on the SSAF and the absence of M greater than or equal to 7 earthquakes on the SSAF since 1857.

Heterogeneous slip and rupture models of the San Andreas fault zone based upon three-dimensional earthquake tomography

Energy Technology Data Exchange (ETDEWEB)

Foxall, William [Univ. of California, Berkeley, CA (United States)

1992-11-01

Crystal fault zones exhibit spatially heterogeneous slip behavior at all scales, slip being partitioned between stable frictional sliding, or fault creep, and unstable earthquake rupture. An understanding the mechanisms underlying slip segmentation is fundamental to research into fault dynamics and the physics of earthquake generation. This thesis investigates the influence that large-scale along-strike heterogeneity in fault zone lithology has on slip segmentation. Large-scale transitions from the stable block sliding of the Central 4D Creeping Section of the San Andreas, fault to the locked 1906 and 1857 earthquake segments takes place along the Loma Prieta and Parkfield sections of the fault, respectively, the transitions being accomplished in part by the generation of earthquakes in the magnitude range 6 (Parkfield) to 7 (Loma Prieta). Information on sub-surface lithology interpreted from the Loma Prieta and Parkfield three-dimensional crustal velocity models computed by Michelini (1991) is integrated with information on slip behavior provided by the distributions of earthquakes located using, the three-dimensional models and by surface creep data to study the relationships between large-scale lithological heterogeneity and slip segmentation along these two sections of the fault zone.

Anomalous hydrogen emissions from the San Andreas fault observed at the Cienega Winery, central California

Science.gov (United States)

Sato, Motoaki; Sutton, A. J.; McGee, K. A.

1984-03-01

We began continuous monitoring of H2 concentration in soil along the San Andreas and Calaveras faults in central California in December 1980, using small H2/O2 fuel-cell sensors. Ten monitoring stations deployed to date have shown that anomalous H2 emissions take place occasionally in addition to diurnal changes. Among the ten sites, the Cienega Winery site has produced data that are characterized by very small diurnal changes, a stable baseline, and remarkably distinct spike-like H2 anomalies since its installation in July 1982. A major peak appeared on 1 10 November 1982, and another on 3 April 1983, and a medium peak on 1 November 1983. The occurrences of these peaks coincided with periods of very low seismicity within a radius of 50 km from the site. In order to methodically assess how these peaks are related to earthquakes, three H2 degassing models were examined. A plausible correlational pattern was obtained by using a model that (1) adopts a hemicircular spreading pattern of H2 along an incipient fracture plane from the hypocenter of an earthquake, (2) relies on the FeO-H2O reaction for H2 generation, and (3) relates the accumulated amount of H2 to the mass of serpentinization of underlying ophiolitic rocks; the mass was tentatively assumed to be proportional to the seismic energy of the earthquake.

Looking for Off-Fault Deformation and Measuring Strain Accumulation During the Past 70 years on a Portion of the Locked San Andreas Fault

Science.gov (United States)

Vadman, M.; Bemis, S. P.

2017-12-01

Even at high tectonic rates, detection of possible off-fault plastic/aseismic deformation and variability in far-field strain accumulation requires high spatial resolution data and likely decades of measurements. Due to the influence that variability in interseismic deformation could have on the timing, size, and location of future earthquakes and the calculation of modern geodetic estimates of strain, we attempt to use historical aerial photographs to constrain deformation through time across a locked fault. Modern photo-based 3D reconstruction techniques facilitate the creation of dense point clouds from historical aerial photograph collections. We use these tools to generate a time series of high-resolution point clouds that span 10-20 km across the Carrizo Plain segment of the San Andreas fault. We chose this location due to the high tectonic rates along the San Andreas fault and lack of vegetation, which may obscure tectonic signals. We use ground control points collected with differential GPS to establish scale and georeference the aerial photograph-derived point clouds. With a locked fault assumption, point clouds can be co-registered (to one another and/or the 1.7 km wide B4 airborne lidar dataset) along the fault trace to calculate relative displacements away from the fault. We use CloudCompare to compute 3D surface displacements, which reflect the interseismic strain accumulation that occurred in the time interval between photo collections. As expected, we do not observe clear surface displacements along the primary fault trace in our comparisons of the B4 lidar data against the aerial photograph-derived point clouds. However, there may be small scale variations within the lidar swath area that represent near-fault plastic deformation. With large-scale historical photographs available for the Carrizo Plain extending back to at least the 1940s, we can potentially sample nearly half the interseismic period since the last major earthquake on this portion of

76 FR 1386 - Safety Zone; Centennial of Naval Aviation Kickoff, San Diego Bay, San Diego, CA

Science.gov (United States)

2011-01-10

...-AA00 Safety Zone; Centennial of Naval Aviation Kickoff, San Diego Bay, San Diego, CA AGENCY: Coast... zone on the navigable waters of San Diego Bay in San Diego, CA in support of the Centennial of Naval... February 12, 2010, the Centennial of Naval Aviation Kickoff will take place in San Diego Bay. In support of...

San Marino.

Science.gov (United States)

1985-02-01

San Marino, an independent republic located in north central Italy, in 1983 had a population of 22,206 growing at an annual rate of .9%. The literacy rate is 97% and the infant mortality rate is 9.6/1000. The terrain is mountainous and the climate is moderate. According to local tradition, San Marino was founded by a Christian stonecutter in the 4th century A.D. as a refuge against religious persecution. Its recorded history began in the 9th century, and it has survived assaults on its independence by the papacy, the Malatesta lords of Rimini, Cesare Borgia, Napoleon, and Mussolini. An 1862 treaty with the newly formed Kingdom of Italy has been periodically renewed and amended. The present government is an alliance between the socialists and communists. San Marino has had its own statutes and governmental institutions since the 11th century. Legislative authority at present is vested in a 60-member unicameral parliament. Executive authority is exercised by the 11-member Congress of State, the members of which head the various administrative departments of the goverment. The posts are divided among the parties which form the coalition government. Judicial authority is partly exercised by Italian magistrates in civil and criminal cases. San Marino's policies are tied to Italy's and political organizations and labor unions active in Italy are also active in San Marino. Since World War II, there has been intense rivalry between 2 political coalitions, the Popular Alliance composed of the Christian Democratic Party and the Independent Social Democratic Party, and the Liberty Committee, coalition of the Communist Party and the Socialist Party. San Marino's gross domestic product was $137 million and its per capita income was $6290 in 1980. The principal economic activities are farming and livestock raising, along with some light manufacturing. Foreign transactions are dominated by tourism. The government derives most of its revenue from the sale of postage stamps to

San Francisco District Laboratory (SAN)

Data.gov (United States)

Federal Laboratory Consortium — Program CapabilitiesFood Analysis SAN-DO Laboratory has an expert in elemental analysis who frequently performs field inspections of materials. A recently acquired...

Constraints on the source parameters of low-frequency earthquakes on the San Andreas Fault

Science.gov (United States)

Thomas, Amanda M.; Beroza, Gregory C.; Shelly, David R.

2016-01-01

Low-frequency earthquakes (LFEs) are small repeating earthquakes that occur in conjunction with deep slow slip. Like typical earthquakes, LFEs are thought to represent shear slip on crustal faults, but when compared to earthquakes of the same magnitude, LFEs are depleted in high-frequency content and have lower corner frequencies, implying longer duration. Here we exploit this difference to estimate the duration of LFEs on the deep San Andreas Fault (SAF). We find that the M ~ 1 LFEs have typical durations of ~0.2 s. Using the annual slip rate of the deep SAF and the average number of LFEs per year, we estimate average LFE slip rates of ~0.24 mm/s. When combined with the LFE magnitude, this number implies a stress drop of ~104 Pa, 2 to 3 orders of magnitude lower than ordinary earthquakes, and a rupture velocity of 0.7 km/s, 20% of the shear wave speed. Typical earthquakes are thought to have rupture velocities of ~80–90% of the shear wave speed. Together, the slow rupture velocity, low stress drops, and slow slip velocity explain why LFEs are depleted in high-frequency content relative to ordinary earthquakes and suggest that LFE sources represent areas capable of relatively higher slip speed in deep fault zones. Additionally, changes in rheology may not be required to explain both LFEs and slow slip; the same process that governs the slip speed during slow earthquakes may also limit the rupture velocity of LFEs.

76 FR 9709 - Water Quality Challenges in the San Francisco Bay/Sacramento-San Joaquin Delta Estuary

Science.gov (United States)

2011-02-22

... Water Quality Challenges in the San Francisco Bay/Sacramento-San Joaquin Delta Estuary AGENCY... the San Francisco Bay/ Sacramento-San Joaquin Delta Estuary (Bay Delta Estuary) in California. EPA is... programs to address recent significant declines in multiple aquatic species in the Bay Delta Estuary. EPA...

33 CFR 165.776 - Security Zone; Coast Guard Base San Juan, San Juan Harbor, Puerto Rico

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone; Coast Guard Base San Juan, San Juan Harbor, Puerto Rico 165.776 Section 165.776 Navigation and Navigable Waters COAST... Guard District § 165.776 Security Zone; Coast Guard Base San Juan, San Juan Harbor, Puerto Rico (a...

The ShakeOut scenario: A hypothetical Mw7.8 earthquake on the Southern San Andreas Fault

Science.gov (United States)

Porter, K.; Jones, L.; Cox, D.; Goltz, J.; Hudnut, K.; Mileti, D.; Perry, S.; Ponti, D.; Reichle, M.; Rose, A.Z.; Scawthorn, C.R.; Seligson, H.A.; Shoaf, K.I.; Treiman, J.; Wein, A.

2011-01-01

In 2008, an earthquake-planning scenario document was released by the U.S. Geological Survey (USGS) and California Geological Survey that hypothesizes the occurrence and effects of a Mw7.8 earthquake on the southern San Andreas Fault. It was created by more than 300 scientists and engineers. Fault offsets reach 13 m and up to 8 m at lifeline crossings. Physics-based modeling was used to generate maps of shaking intensity, with peak ground velocities of 3 m/sec near the fault and exceeding 0.5 m/sec over 10,000 km2. A custom HAZUS??MH analysis and 18 special studies were performed to characterize the effects of the earthquake on the built environment. The scenario posits 1,800 deaths and 53,000 injuries requiring emergency room care. Approximately 1,600 fires are ignited, resulting in the destruction of 200 million square feet of the building stock, the equivalent of 133,000 single-family homes. Fire contributes $87 billion in property and business interruption loss, out of the total $191 billion in economic loss, with most of the rest coming from shakerelated building and content damage ($46 billion) and business interruption loss from water outages ($24 billion). Emergency response activities are depicted in detail, in an innovative grid showing activities versus time, a new format introduced in this study. ?? 2011, Earthquake Engineering Research Institute.

Data from theodolite measurements of creep rates on San Francisco Bay region faults, California, 1979-2012

Science.gov (United States)

McFarland, Forrest S.; Lienkaemper, James J.; Caskey, S. John

2009-01-01

Our purpose is to annually update our creep-data archive on San Francisco Bay region active faults for use by the scientific research community. Earlier data (1979-2001) were reported in Galehouse (2002) and were analyzed and described in detail in a summary report (Galehouse and Lienkaemper, 2003). A complete analysis of our earlier results obtained on the Hayward Fault was presented in Lienkaemper, Galehouse and Simpson (2001) and updated in Lienkaemper and others (2012). Lienkaemper and others (2014a) provide a new overview and analysis of fault creep along all sections of the northern San Andreas Fault system, from which they estimate by how much fault creep reduces the seismic hazard for each fault section.

Enhanced Preliminary Assessment Report: Presidio of San Francisco Military Reservation, San Francisco, California

Science.gov (United States)

1989-11-01

CAD981415656 Filmore Steiner Bay San Francisco 24 PG&E Gas Plant SanFran 502-IG CAD981415714 Bay North Point Buchanan Laguna 25 PG&E Gas Plant SanFran 502-1H...76-ioV /5,JO /0.7 /,230 PSF Water PSF, Main U.N. Lagunda Honda Analvte Plant Clearwell Reservoir Plaza Reservoi- Chlordane inetab. ə.2 ə.2 (1.2 ə.2

Remote triggering of fault-strength changes on the San Andreas fault at Parkfield.

Science.gov (United States)

Taira, Taka'aki; Silver, Paul G; Niu, Fenglin; Nadeau, Robert M

2009-10-01

Fault strength is a fundamental property of seismogenic zones, and its temporal changes can increase or decrease the likelihood of failure and the ultimate triggering of seismic events. Although changes in fault strength have been suggested to explain various phenomena, such as the remote triggering of seismicity, there has been no means of actually monitoring this important property in situ. Here we argue that approximately 20 years of observation (1987-2008) of the Parkfield area at the San Andreas fault have revealed a means of monitoring fault strength. We have identified two occasions where long-term changes in fault strength have been most probably induced remotely by large seismic events, namely the 2004 magnitude (M) 9.1 Sumatra-Andaman earthquake and the earlier 1992 M = 7.3 Landers earthquake. In both cases, the change possessed two manifestations: temporal variations in the properties of seismic scatterers-probably reflecting the stress-induced migration of fluids-and systematic temporal variations in the characteristics of repeating-earthquake sequences that are most consistent with changes in fault strength. In the case of the 1992 Landers earthquake, a period of reduced strength probably triggered the 1993 Parkfield aseismic transient as well as the accompanying cluster of four M > 4 earthquakes at Parkfield. The fault-strength changes produced by the distant 2004 Sumatra-Andaman earthquake are especially important, as they suggest that the very largest earthquakes may have a global influence on the strength of the Earth's fault systems. As such a perturbation would bring many fault zones closer to failure, it should lead to temporal clustering of global seismicity. This hypothesis seems to be supported by the unusually high number of M >or= 8 earthquakes occurring in the few years following the 2004 Sumatra-Andaman earthquake.

76 FR 10945 - San Luis Trust Bank, FSB, San Luis Obispo, CA; Notice of Appointment of Receiver

Science.gov (United States)

2011-02-28

... DEPARTMENT OF THE TREASURY Office of Thrift Supervision San Luis Trust Bank, FSB, San Luis Obispo, CA; Notice of Appointment of Receiver Notice is hereby given that, pursuant to the authority... appointed the Federal Deposit Insurance Corporation as sole Receiver for San Luis Trust Bank, FSB, San Luis...

Inferring fault rheology from low-frequency earthquakes on the San Andreas

Science.gov (United States)

Beeler, Nicholas M.; Thomas, Amanda; Bürgmann, Roland; Shelly, David R.

2013-01-01

Families of recurring low-frequency earthquakes (LFEs) within nonvolcanic tremor (NVT) on the San Andreas fault in central California show strong sensitivity to shear stress induced by the daily tidal cycle. LFEs occur at all levels of the tidal shear stress and are in phase with the very small, ~400 Pa, stress amplitude. To quantitatively explain the correlation, we use a model from the existing literature that assumes the LFE sources are small, persistent regions that repeatedly fail during shear of a much larger scale, otherwise aseismically creeping fault zone. The LFE source patches see tectonic loading, creep of the surrounding fault which may be modulated by the tidal stress, and direct tidal loading. If the patches are small relative to the surrounding creeping fault then the stressing is dominated by fault creep, and if patch failure occurs at a threshold stress, then the resulting seismicity rate is proportional to the fault creep rate or fault zone strain rate. Using the seismicity rate as a proxy for strain rate and the tidal shear stress, we fit the data with possible fault rheologies that produce creep in laboratory experiments at temperatures of 400 to 600°C appropriate for the LFE source depth. The rheological properties of rock-forming minerals for dislocation creep and dislocation glide are not consistent with the observed fault creep because strong correlation between small stress perturbations and strain rate requires perturbation on the order of the ambient stress. The observed tidal modulation restricts ambient stress to be at most a few kilopascal, much lower than rock strength. A purely rate dependent friction is consistent with the observations only if the product of the friction rate dependence and effective normal stress is ~ 0.5 kPa. Extrapolating the friction rate strengthening dependence of phyllosilicates (talc) to depth would require the effective normal stress to be ~50 kPa, implying pore pressure is lithostatic. If the LFE

Structural Mapping Along the Central San Andreas Fault-zone Using Airborne Electromagnetics

Science.gov (United States)

Zamudio, K. D.; Bedrosian, P.; Ball, L. B.

2017-12-01

Investigations of active fault zones typically focus on either surface expressions or the associated seismogenic zones. However, the largely aseismic upper kilometer can hold significant insight into fault-zone architecture, strain partitioning, and fault-zone permeability. Geophysical imaging of the first kilometer provides a link between surface fault mapping and seismically-defined fault zones and is particularly important in geologically complex regions with limited surface exposure. Additionally, near surface imaging can provide insight into the impact of faulting on the hydrogeology of the critical zone. Airborne electromagnetic (AEM) methods offer a unique opportunity to collect a spatially-large, detailed dataset in a matter of days, and are used to constrain subsurface resistivity to depths of 500 meters or more. We present initial results from an AEM survey flown over a 60 kilometer long segment of the central San Andreas Fault (SAF). The survey is centered near Parkfield, California, the site of the SAFOD drillhole, which marks the transition between a creeping fault segment to the north and a locked zone to the south. Cross sections with a depth of investigation up to approximately 500 meters highlight the complex Tertiary and Mesozoic geology that is dismembered by the SAF system. Numerous fault-parallel structures are imaged across a more than 10 kilometer wide zone centered on the surface trace. Many of these features can be related to faults and folds within Plio-Miocene sedimentary rocks found on both sides of the fault. Northeast of the fault, rocks of the Mesozoic Franciscan and Great Valley complexes are extremely heterogeneous, with highly resistive volcanic rocks within a more conductive background. The upper 300 meters of a prominent fault-zone conductor, previously imaged to 1-3 kilometers depth by magnetotellurics, is restricted to a 20 kilometer long segment of the fault, but is up to 4 kilometers wide in places. Elevated fault

76 FR 22809 - Safety Zone; Bay Ferry II Maritime Security Exercise; San Francisco Bay, San Francisco, CA

Science.gov (United States)

2011-04-25

... DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 165 [Docket No. USCG-2011-0196] RIN 1625-AA00 Safety Zone; Bay Ferry II Maritime Security Exercise; San Francisco Bay, San Francisco, CA AGENCY... Security Exercise; San Francisco Bay, San Francisco, CA. (a) Location. The limits of this safety zone...

Off-fault seismicity suggests creep below 10 km on the northern San Jacinto Fault

Science.gov (United States)

Cooke, M. L.; Beyer, J. L.

2017-12-01

Within the San Bernardino basin, CA, south of the juncture of the San Jacinto (SJF) and San Andreas faults (SAF), focal mechanisms show normal slip events that are inconsistent with the interseismic strike-slip loading of the region. High-quality (nodal plane uncertainty faults [Anderson et al., 2004]. However, the loading of these normal slip events remains enigmatic because the region is expected to have dextral loading between large earthquake events. These enigmatic normal slip events may be loaded by deep (> 10 km depth) spatially creep along the northern SJF. Steady state models show that over many earthquake cycles, the dextral slip rate on the northern SJF increases southward, placing the San Bernardino basin in extension. In the absence of recent large seismic events that could produce off-fault normal focal mechanisms in the San Bernardino basin, non-uniform deep aseismic slip on the SJF could account for this seismicity. We develop interseismic models that incorporate spatially non-uniform creep below 10 km on the SJF based on steady-state slip distribution. These model results match the pattern of deep normal slip events within the San Bernardino basin. Such deep creep on the SJF may not be detectable from the geodetic signal due to the close proximity of the SAF, whose lack of seismicity suggests that it is locked to 20 km. Interseismic models with 15 km locking depth on both faults are indistinguishable from models with 10 km locking depth on the SJF and 20 km locking depth on the SAF. This analysis suggests that the microseismicity in our multi-decadal catalog may record both the interseismic dextral loading of the region as well as off-fault deformation associated with deep aseismic creep on the northern SJF. If the enigmatic normal slip events of the San Bernardino basin are included in stress inversions from the seismic catalog used to assess seismic hazard, the results may provide inaccurate information about fault loading in this region.

The San Bernabe power substation; La subestacion San Bernabe

Energy Technology Data Exchange (ETDEWEB)

Chavez Sanudo, Andres D. [Luz y Fuerza del Centro, Mexico, D. F. (Mexico)

1997-12-31

The first planning studies that gave rise to the San Bernabe substation go back to year 1985. The main circumstance that supports this decision is the gradual restriction for electric power generation that has been suffering the Miguel Aleman Hydro System, until its complete disappearance, to give priority to the potable water supply through the Cutzamala pumping system, that feeds in an important way Mexico City and the State of Mexico. In this document the author describes the construction project of the San Bernabe Substation; mention is made of the technological experiences obtained during the construction and its geographical location is shown, as well as the one line diagram of the same [Espanol] Los primeros estudios de planeacion que dieron origen a la subestacion San Bernabe se remontan al ano de 1985. La circunstancia principal que soporta esta decision es la restriccion paulatina para generar energia que ha venido experimentando el Sistema Hidroelectrico Miguel Aleman, hasta su desaparicion total, para dar prioridad al suministro de agua potable por medio del sistema de bombeo Cutzamala, que alimenta en forma importante a la Ciudad de Mexico y al Estado de Mexico. En este documento el autor describe el proyecto de construccion de la subestacion San Bernabe; se mencionan las experiencias tecnologicas obtenidas durante su construccion y se ilustra su ubicacion geografica, asi como un diagrama unifilar de la misma

Description of gravity cores from San Pablo Bay and Carquinez Strait, San Francisco Bay, California

Science.gov (United States)

Woodrow, Donald L.; John L. Chin,; Wong, Florence L.; Fregoso, Theresa A.; Jaffe, Bruce E.

2017-06-27

Seventy-two gravity cores were collected by the U.S. Geological Survey in 1990, 1991, and 2000 from San Pablo Bay and Carquinez Strait, California. The gravity cores collected within San Pablo Bay contain bioturbated laminated silts and sandy clays, whole and broken bivalve shells (mostly mussels), fossil tube structures, and fine-grained plant or wood fragments. Gravity cores from the channel wall of Carquinez Strait east of San Pablo Bay consist of sand and clay layers, whole and broken bivalve shells (less than in San Pablo Bay), trace fossil tubes, and minute fragments of plant material.

Geophysical and isotopic mapping of preexisting crustal structures that influenced the location and development of the San Jacinto fault zone, southern California

Science.gov (United States)

Langenheim, V.E.; Jachens, R.C.; Morton, D.M.; Kistler, R.W.; Matti, J.C.

2004-01-01

We examine the role of preexisting crustal structure within the Peninsular Ranges batholith on determining the location of the San Jacinto fault zone by analysis of geophysical anomalies and initial strontium ratio data. A 1000-km-long boundary within the Peninsular Ranges batholith, separating relatively mafic, dense, and magnetic rocks of the western Peninsular Ranges batholith from the more felsic, less dense, and weakly magnetic rocks of the eastern Peninsular Ranges batholith, strikes north-northwest toward the San Jacinto fault zone. Modeling of the gravity and magnetic field anomalies caused by this boundary indicates that it extends to depths of at least 20 km. The anomalies do not cross the San Jacinto fault zone, but instead trend northwesterly and coincide with the fault zone. A 75-km-long gradient in initial strontium ratios (Sri) in the eastern Peninsular Ranges batholith coincides with the San Jacinto fault zone. Here rocks east of the fault are characterized by Sri greater than 0.706, indicating a source of largely continental crust, sedimentary materials, or different lithosphere. We argue that the physical property contrast produced by the Peninsular Ranges batholith boundary provided a mechanically favorable path for the San Jacinto fault zone, bypassing the San Gorgonio structural knot as slip was transferred from the San Andreas fault 1.0-1.5 Ma. Two historical M6.7 earthquakes may have nucleated along the Peninsular Ranges batholith discontinuity in San Jacinto Valley, suggesting that Peninsular Ranges batholith crustal structure may continue to affect how strain is accommodated along the San Jacinto fault zone. ?? 2004 Geological Society of America.

78 FR 34123 - Notice of Inventory Completion: San Francisco State University NAGPRA Program, San Francisco, CA

Science.gov (United States)

2013-06-06

... completion of an inventory of human remains and associated funerary objects under the control of the San....R50000] Notice of Inventory Completion: San Francisco State University NAGPRA Program, San Francisco, CA... NAGPRA Program has completed an inventory of human remains and associated funerary objects, in...

78 FR 21403 - Notice of Inventory Completion: San Francisco State University NAGPRA Program, San Francisco, CA

Science.gov (United States)

2013-04-10

... completion of an inventory of human remains and associated funerary objects under the control of the San....R50000] Notice of Inventory Completion: San Francisco State University NAGPRA Program, San Francisco, CA... NAGPRA Program has completed an inventory of human remains and associated funerary objects, in...

75 FR 15611 - Safety Zone; United Portuguese SES Centennial Festa, San Diego Bay, San Diego, CA

Science.gov (United States)

2010-03-30

...-AA00 Safety Zone; United Portuguese SES Centennial Festa, San Diego Bay, San Diego, CA AGENCY: Coast... navigable waters of the San Diego Bay in support of the United Portuguese SES Centennial Festa. This... Centennial Festa, which will include a fireworks presentation originating from a tug and barge combination in...

Deformation mechanisms in the San Andreas Fault zone - a comparison between natural and experimentally deformed microstructures

Science.gov (United States)

van Diggelen, Esther; Holdsworth, Robert; de Bresser, Hans; Spiers, Chris

2010-05-01

The San Andreas Fault (SAF) in California marks the boundary between the Pacific plate and the North American plate. The San Andreas Fault Observatory at Depth (SAFOD) is located 9 km northwest of the town of Parkfield, CA and provide an extensive set of samples through the SAF. The SAFOD drill hole encountered different lithologies, including arkosic sediments from the Salinian block (Pacific plate) and claystones and siltstones from the Great Valley block (North American plate). Fault deformation in the area is mainly by a combination of micro-earthquakes and fault creep. Deformation of the borehole casing indicated that the SAFOD drill hole cross cuts two actively deforming strands of the SAF. In order to determine the deformation mechanisms in the actively creeping fault segments, we have studied thin sections obtained from SAFOD phase 3 core material using optical and electron microscopy, and we have compared these natural SAFOD microstructures with microstructures developed in simulated fault gouges deformed in laboratory shear experiments. The phase 3 core material is divided in three different core intervals consisting of different lithologies. Core interval 1 consists of mildly deformed Salinian rocks that show evidence of cataclasis, pressure solution and reaction of feldspar to form phyllosilicates, all common processes in upper crustal rocks. Most of Core interval 3 (Great Valley) is also only mildly deformed and very similar to Core interval 1. Bedding and some sedimentary features are still visible, together with limited evidence for cataclasis and pressure solution, and reaction of feldspar to form phyllosilicates. However, in between the relatively undeformed rocks, Core interval 3 encountered a zone of foliated fault gouge, consisting mostly of phyllosilicates. This zone is correlated with one of the zones of localized deformation of the borehole casing, i.e. with an actively deforming strand of the SAF. The fault gouge zone shows a strong, chaotic

Performance of BATAN-SANS instrument

Energy Technology Data Exchange (ETDEWEB)

Ikram, Abarrul; Insani, Andon [National Nuclear Energy Agency, P and D Centre for Materials Science and Technology, Serpong (Indonesia)

2003-03-01

SANS data from some standard samples have been obtained using BATAN-SANS instrument in Serpong. The experiments were performed for various experimental set-ups that involve different detector positions and collimator lengths. This paper describes the BATAN-SANS instrument briefly as well as the data taken from those experiments and followed with discussion of the results concerning the performance and calibration of the instrument. The standard samples utilized in these experiments include porous silica, polystyrene-poly isoprene, silver behenate, poly ball and polystyrene-poly (ethylene-alt-propylene). Even though the results show that BATAN-SANS instrument is in good shape, but rooms for improvements are still widely open especially for the velocity selector and its control system. (author)

Structural features of the San Andreas fault at Tejon Pass, California

Science.gov (United States)

Dewers, T. A.; Reches, Z.; Brune, J. N.

2002-12-01

We mapped a 2 km belt along the San Andreas fault (SAF) in the Tejon Pass area where road cuts provide fresh exposures of the fault zone and surrounding rocks. Our 1:2,000 structural mapping is focused on analysis of faulting processes and is complementary to regional mapping at 1:12,000 scale by Ramirez (M.Sc., UC Santa Barbara, 1984). The dominant rock units are the Hungry Valley Formation of Pliocene age (clastic sediments) exposed south of the SAF, and the Tejon Lookout granite (Cretaceous) and Neenach Volcanic Formation exposed north of it. Ramirez (1983) deduced ~220 km of post-Miocene lateral slip. The local trend of the SAF is about N60W and it includes at least three main, subparallel segments that form a 200 m wide zone. The traces of the segments are quasi-linear, discontinuous, and they are stepped with respect to each other, forming at least five small pull-aparts and sag ponds in the mapping area. The three segments were not active semi-contemporaneously and the southern segment is apparently the oldest. The largest pull-apart, 60-70 m wide, displays young (Quaternary?) silt and shale layers. We found two rock bodies that are suspected as fault-rocks. One is a 1-2 m thick sheet-like body that separates the Tejon Lookout granite from young (Recent?) clastic rocks. In the field, it appears as a gouge zone composed of poorly cemented, dark clay size grains; however, the microstructure of this rock does not reveal clear shear features. The second body is the 80-120 m wide zone of Tejon Lookout granite that extends for less than 1 km along the SAF in the mapped area. It is characterized by three structural features: (1) pulverization into friable, granular material by multitude of grain-crossing fractures; (2) abundance of dip-slip small faults that are gently dipping toward and away from the SAF; and (3) striking lack of evidence for shear parallel to the SAF. The relationships between these features and the large right-lateral shear along the SAF are

On the origin of mixed-layered clay minerals from the San Andreas Fault at 2.5-3 km vertical depth (SAFOD drillhole at Parkfield, California)

Science.gov (United States)

Schleicher, A. M.; Warr, L. N.; van der Pluijm, B. A.

2009-02-01

A detailed mineralogical study is presented of the matrix of mudrocks sampled from spot coring at three key locations along the San Andreas Fault Observatory at depth (SAFOD) drill hole. The characteristics of authigenic illite-smectite (I-S) and chlorite-smectite (C-S) mixed-layer mineral clays indicate a deep diagenetic origin. A randomly ordered I-S mineral with ca. 20-25% smectite layers is one of the dominant authigenic clay species across the San Andreas Fault zone (sampled at 3,066 and 3,436 m measured depths/MD), whereas an authigenic illite with ca. 2-5% smectite layers is the dominant phase beneath the fault (sampled at 3,992 m MD). The most smectite-rich mixed-layered assemblage with the highest water content occurs in the actively deforming creep zone at ca. 3,300-3,353 m (true vertical depth of ca. 2.7 km), with I-S (70:30) and C-S (50:50). The matrix of all mudrock samples show extensive quartz and feldspar (both plagioclase and K-feldspar) dissolution associated with the crystallization of pore-filling clay minerals. However, the effect of rock deformation in the matrix appears only minor, with weak flattening fabrics defined largely by kinked and fractured mica grains. Adopting available kinetic models for the crystallization of I-S in burial sedimentary environments and the current borehole depths and thermal structure, the conditions and timing of I-S growth can be evaluated. Assuming a typical K+ concentration of 100-200 ppm for sedimentary brines, a present-day geothermal gradient of 35°C/km and a borehole temperature of ca. 112°C for the sampled depths, most of the I-S minerals can be predicted to have formed over the last 4-11 Ma and are probably still in equilibrium with circulating fluids. The exception to this simple burial pattern is the occurrence of the mixed layered phases with higher smectite content than predicted by the burial model. These minerals, which characterize the actively creeping section of the fault and local thin film

Characterizing the Relationship Between Lithospheric Deformation and Seismic Anisotropy in the Basin and Range Province and San Andreas Fault System using Ps Receiver Function Analysis

Science.gov (United States)

Ford, H. A.; Schnorr, E.

2017-12-01

The presence of complex and spatially variable anisotropy in many parts of the western U.S. has been tied to regional tectonic and dynamic processes that go beyond the (frequently) assumed plate motion oriented shear. In the Basin and Range, a well-imaged "swirl" of shear wave splitting observations has been explained via a number of different dynamic processes, including a lithospheric drip and toroidal flow. In central California, rapid variations in splitting direction across the plate boundary have been attributed to a relatively narrow, well-defined shear zone. Ambient noise tomography has further complicated the picture, indicating that some of the observed complexity can be explained by incorporating multiple layers of anisotropy. The goal of this study is to place firm constraints on vertical variations in anisotropy over two tectonically distinct, yet related, regions- the Basin and Range province and the San Andreas fault system, in order to better understand how deformation of the lithosphere is accommodated. To do this, radial and transverse component Ps receiver functions have been calculated for 14 stations within the two regions. Within both study areas, variability exists between most stations at crust and lithospheric mantle depths. This is particularly true for stations located near the San Andreas Fault system. These differences may be attributed to variations in the provenance of the lithospheric "packages" in some areas, however several stations are located near or within the plate boundary system and may be sampling multiple regions with varying deformation fabrics. To account for this, future work will include binning as a function of piercing point. One notable exception to the generally observed variability is along the western margin of the Basin and Range, where several stations show similarities in back azimuthal variations at lower crust and uppermost mantle depths. Preliminary forwarding modeling of two of these stations indicates that

Hydrothermal frictional strengths of rock and mineral samples relevant to the creeping section of the San Andreas Fault

Science.gov (United States)

Moore, Diane E.; Lockner, David A.; Hickman, Stephen H.

2016-01-01

We compare frictional strengths in the temperature range 25–250 °C of fault gouge from SAFOD (CDZ and SDZ) with quartzofeldspathic wall rocks typical of the central creeping section of the San Andreas Fault (Great Valley sequence and Franciscan Complex). The Great Valley and Franciscan samples have coefficients of friction, μ > 0.35 at all experimental conditions. Strength is unchanged between 25° and 150 °C, but μ increases at higher temperatures, exceeding 0.50 at 250 °C. Both samples are velocity strengthening at room temperature but show velocity-weakening behavior beginning at 150 °C and stick-slip motion at 250 °C. These rocks, therefore, have the potential for unstable seismic slip at depth. The CDZ gouge, with a high saponite content, is weak (μ = 0.09–0.17) and velocity strengthening in all experiments, and μ decreases at temperatures above 150 °C. Behavior of the SDZ is intermediate between the CDZ and wall rocks: μ < 0.2 and does not vary with temperature. Although saponite is probably not stable at depths greater than ∼3 km, substitution of the frictionally similar minerals talc and Mg-rich chlorite for saponite at higher temperatures could potentially extend the range of low strength and stable slip down to the base of the seismogenic zone.

San Marco C-2 (San Marco-4) Post Launch Report No. 1

Science.gov (United States)

1974-01-01

The San Marco C-2 spacecraft, now designated San Marco-4, was successfully launched by a Scout vehicle from the San Marco Platform on 18 February 1974 at 6:05 a.m. EDT. The launch occurred 2 hours 50 minutes into the 3-hour window due co low cloud cover at the launch site. All spacecraft subsystems have been checked and are functioning normally. The protective caps for the two U.S. experiments were ejected and the Omegatron experiment activated on 19 February. The neutral mass spectrometer was activated as scheduled on 22 February after sufficient time to allow for spacecraft outgassing and to avoid the possibility of corona occurring. Both instruments are performing properly and worthwhile scientific data is being acquired.

77 FR 34988 - Notice of Inventory Completion: San Diego State University, San Diego, CA

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2012-06-12

.... ACTION: Notice. SUMMARY: San Diego State University Archeology Collections Management Program has... that believes itself to be culturally affiliated with the human remains and associated funerary objects may contact San Diego State University Archeology Collections Management Program. Repatriation of the...

Fractal properties and simulation of micro-seismicity for seismic hazard analysis: a comparison of North Anatolian and San Andreas Fault Zones

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Naside Ozer

2012-02-01

Full Text Available We analyzed statistical properties of earthquakes in western Anatolia as well as the North Anatolian Fault Zone (NAFZ in terms of spatio-temporal variations of fractal dimensions, p- and b-values. During statistically homogeneous periods characterized by closer fractal dimension values, we propose that occurrence of relatively larger shocks (M >= 5.0 is unlikely. Decreases in seismic activity in such intervals result in spatial b-value distributions that are primarily stable. Fractal dimensions decrease with time in proportion to increasing seismicity. Conversely, no spatiotemporal patterns were observed for p-value changes. In order to evaluate failure probabilities and simulate earthquake occurrence in the western NAFZ, we applied a modified version of the renormalization group method. Assuming an increase in small earthquakes is indicative of larger shocks, we apply the mentioned model to micro-seismic (M<= 3.0 activity, and test our results using San Andreas Fault Zone (SAFZ data. We propose that fractal dimension is a direct indicator of material heterogeneity and strength. Results from a model suggest simulated and observed earthquake occurrences are coherent, and may be used for seismic hazard estimation on creeping strike-slip fault zones.

Zoogeography of the San Andreas Fault system: Great Pacific Fracture Zones correspond with spatially concordant phylogeographic boundaries in western North America.

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Gottscho, Andrew D

2016-02-01

The purpose of this article is to provide an ultimate tectonic explanation for several well-studied zoogeographic boundaries along the west coast of North America, specifically, along the boundary of the North American and Pacific plates (the San Andreas Fault system). By reviewing 177 references from the plate tectonics and zoogeography literature, I demonstrate that four Great Pacific Fracture Zones (GPFZs) in the Pacific plate correspond with distributional limits and spatially concordant phylogeographic breaks for a wide variety of marine and terrestrial animals, including invertebrates, fish, amphibians, reptiles, birds, and mammals. These boundaries are: (1) Cape Mendocino and the North Coast Divide, (2) Point Conception and the Transverse Ranges, (3) Punta Eugenia and the Vizcaíno Desert, and (4) Cabo Corrientes and the Sierra Transvolcanica. However, discussion of the GPFZs is mostly absent from the zoogeography and phylogeography literature likely due to a disconnect between biologists and geologists. I argue that the four zoogeographic boundaries reviewed here ultimately originated via the same geological process (triple junction evolution). Finally, I suggest how a comparative phylogeographic approach can be used to test the hypothesis presented here. © 2014 Cambridge Philosophical Society.

Magnetic profiling of the San Andreas Fault using a dual magnetometer UAV aerial survey system.

Science.gov (United States)

Abbate, J. A.; Angelopoulos, V.; Masongsong, E. V.; Yang, J.; Medina, H. R.; Moon, S.; Davis, P. M.

2017-12-01

Aeromagnetic survey methods using planes are more time-effective than hand-held methods, but can be far more expensive per unit area unless large areas are covered. The availability of low cost UAVs and low cost, lightweight fluxgate magnetometers (FGMs) allows, with proper offset determination and stray fields correction, for low-cost magnetic surveys. Towards that end, we have developed a custom multicopter UAV for magnetic mapping using a dual 3-axis fluxgate magnetometer system: the GEOphysical Drone Enhanced Survey Instrument (GEODESI). A high precision sensor measures the UAV's position and attitude (roll, pitch, and yaw) and is recorded using a custom Arduino data processing system. The two FGMs (in-board and out-board) are placed on two ends of a vertical 1m boom attached to the base of the UAV. The in-board FGM is most sensitive to stray fields from the UAV and its signal is used, after scaling, to clean the signal of the out-board FGM from the vehicle noise. The FGMs record three orthogonal components of the magnetic field in the UAV body coordinates which are then transformed into a north-east-down coordinate system using a rotation matrix determined from the roll-pitch-yaw attitude data. This ensures knowledge of the direction of all three field components enabling us to perform inverse modeling of magnetic anomalies with greater accuracy than total or vertical field measurements used in the past. Field tests were performed at Dragon's Back Pressure Ridge in the Carrizo Plain of California, where there is a known crossing of the San Andreas Fault. Our data and models were compared to previously acquired LiDAR and hand-held magnetometer measurements. Further tests will be carried out to solidify our results and streamline our processing for educational use in the classroom and student field training.

78 FR 53243 - Safety Zone; TriRock San Diego, San Diego Bay, San Diego, CA

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2013-08-29

... this rule because the logistical details of the San Diego Bay triathlon swim were not finalized nor... September 22, 2013. (c) Definitions. The following definition applies to this section: Designated...

Structure of the San Andreas Fault Zone in the Salton Trough Region of Southern California: A Comparison with San Andreas Fault Structure in the Loma Prieta Area of Central California

Science.gov (United States)

Fuis, G. S.; Catchings, R.; Scheirer, D. S.; Goldman, M.; Zhang, E.; Bauer, K.

2016-12-01

The San Andreas fault (SAF) in the northern Salton Trough, or Coachella Valley, in southern California, 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 Valley have been obtained from analysis of steep reflections, earthquakes, modeling of potential-field data, and P-wave tomography. Review of seismological and geodetic research on the 1989 M 6.9 Loma Prieta earthquake, in central California (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 earthquake 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 Valley. But importantly, the SAF, interpreted here to include the main rupture plane, appears segmented, as in the Coachella Valley, 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

Delayed dynamic triggering of deep tremor along the Parkfield-Cholame section of the San Andreas Fault following the 2014 M6.0 South Napa earthquake

Science.gov (United States)

Peng, Zhigang; Shelly, David R.; Ellsworth, William L.

2015-01-01

Large, distant earthquakes are known to trigger deep tectonic tremor along the San Andreas Fault and in subduction zones. However, there are relatively few observations of triggering from regional distance earthquakes. Here we show that a small tremor episode about 12–18 km NW of Parkfield was triggered during and immediately following the passage of surface waves from the 2014 Mw 6.0 South Napa main shock. More notably, a major tremor episode followed, beginning about 12 h later, and centered SE of Parkfield near Cholame. This major episode is one of the largest seen over the past several years, containing intense activity for ~3 days and taking more than 3 weeks to return to background levels. This episode showed systematic along-strike migration at ~5 km/d, suggesting that it was driven by a slow-slip event. Our results suggest that moderate-size earthquakes are capable of triggering major tremor and deep slow slip at regional distances.

77 FR 59969 - Notice of Inventory Completion: San Francisco State University, Department of Anthropology, San...

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2012-10-01

... Inventory Completion: San Francisco State University, Department of Anthropology, San Francisco, CA... Francisco State University, NAGPRA Program (formerly in the Department of Anthropology). The human remains... State University Department of Anthropology records. In the Federal Register (73 FR 30156-30158, May 23...

33 CFR 165.1182 - Safety/Security Zone: San Francisco Bay, San Pablo Bay, Carquinez Strait, and Suisun Bay, CA.

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2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Safety/Security Zone: San... Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY... Areas Eleventh Coast Guard District § 165.1182 Safety/Security Zone: San Francisco Bay, San Pablo Bay...

SAN MICHELE. ENTRE CIELO Y MAR / San Michele, between sky and sea

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Pablo Blázquez Jesús

2012-11-01

Full Text Available RESUMEN El cementerio es uno de los tipos arquitectónicos más profundos y metafóricos. El concurso para la ampliación del cementerio de San Michele, convocado en 1998 por la administración Municipal de Venecia, se convierte en un excelente campo de pruebas sobre el que poder analizar el contexto histórico en torno a esta tipología, y su relación con la ciudad y el territorio. El estudio de este caso concreto nos permite descubrir personajes, relaciones casuales y hallazgos que se despliegan a lo largo del texto. La historia del cementerio de San Michele es también la crónica de la transformación de la ciudad de Venecia y su Laguna. Interpretando este concurso como un instrumento de investigación, el objetivo del artículo es el de comprender la realidad contemporánea de la arquitectura funeraria a través de la isla de San Michele, Venecia, y las propuestas finalistas de Carlos Ferrater, Enric Miralles y David Chipperfield. Una historia bajo la cual se vislumbran claves que nos sirven para reflexionar acerca del cementerio contemporáneo, la ciudad y el territorio. SUMMARY The cemetery is one of the most profound and metaphorical kinds of architecture. The competition for the extension of the San Michele Cemetery, called in 1998 by the Venice municipal administration, is an excellent testing ground on which to analyse the historical context surrounding this type of architecture, and its relationship with the city and the region. The study of this particular case allows us to uncover characters, casual relationships and findings that unfold throughout the text. The history of the San Michele cemetery is also the chronicle of the transformation of the city of Venice and its Lagoon. Interpreting this competition as a research tool, the aim of the paper is to understand the contemporary reality of funerary architecture through the island of San Michele, Venice, and the finalist proposals of Carlos Ferrater, Enric Miralles and David

Deep rock damage in the San Andreas Fault revealed by P- and S-type fault-zone-guided waves

Science.gov (United States)

Ellsworth, William L.; Malin, Peter E.

2011-01-01

Damage to fault-zone rocks during fault slip results in the formation of a channel of low seismic-wave velocities. Within such channels guided seismic waves, denoted by Fg, can propagate. Here we show with core samples, well logs and Fg-waves that such a channel is crossed by the SAFOD (San Andreas Fault Observatory at Depth) borehole at a depth of 2.7 km near Parkfield, California, USA. This laterally extensive channel extends downwards to at least half way through the seismogenic crust, more than about 7 km. The channel supports not only the previously recognized Love-type- (FL) and Rayleigh-type- (FR) guided waves, but also a new fault-guided wave, which we name FF. As recorded 2.7 km underground, FF is normally dispersed, ends in an Airy phase, and arrives between the P- and S-waves. Modelling shows that FF travels as a leaky mode within the core of the fault zone. Combined with the drill core samples, well logs and the two other types of guided waves, FF at SAFOD reveals a zone of profound, deep, rock damage. Originating from damage accumulated over the recent history of fault movement, we suggest it is maintained either by fracturing near the slip surface of earthquakes, such as the 1857 Fort Tejon M 7.9, or is an unexplained part of the fault-creep process known to be active at this site.

Using low-frequency earthquake families on the San Andreas fault as deep creepmeters

Science.gov (United States)

Thomas, A.; Beeler, N. M.; Bletery, Q.; Burgmann, R.; Shelly, D. R.

2017-12-01

The San Andreas fault hosts tectonic tremor and low-frequency earthquakes (LFEs) similar to those in subduction zone environments. These LFEs are grouped into families based on waveform similarity and locate between 16 and 29 km depth along a 150-km-long section of the fault centered on Parkfield, CA. ­Within individual LFE families event occurrence is not steady. In some families, bursts of a few events recur on timescales of days while in other families there are nearly quiescent periods that often last for months followed by episodes where hundreds of events occur over the course of a few days. These two different styles of LFE occurrence are called continuous and episodic respectively. LFEs are often assumed to reflect persistent regions that periodically fail during the aseismic shear of the surrounding fault allowing them to be used as creepmeters. We test this idea by formalizing the definition of a creepmeter (the LFE occurrence rate is proportional to the local fault slip rate), determining whether this definition is consistent with the observations, and over what timescale. We use the recurrence intervals of LFEs within individual families to create a catalog of LFE bursts. For the episodic families, we consider both longer duration (multiday) inferred creep episodes (dubbed long-timescale episodic) as well as the frequent short-term bursts of events that occur many times during inferred creep episodes (dubbed short-timescale episodic). We then use the recurrence intervals of LFE bursts to estimate the timing, duration, recurrence interval, slip, and slip rate associated with inferred slow slip events. We find that continuous families and the short-timescale episodic families appear to be inconsistent with our definition of a creepmeter (defined on the recurrence interval timescale) because their estimated durations are not physically meaningful. A straight-forward interpretation of the frequent short-term bursts of the continuous and short

Frictional strength and heat flow of southern San Andreas Fault

Science.gov (United States)

Zhu, P. P.

2016-01-01

Frictional strength and heat flow of faults are two related subjects in geophysics and seismology. To date, the investigation on regional frictional strength and heat flow still stays at the stage of qualitative estimation. This paper is concentrated on the regional frictional strength and heat flow of the southern San Andreas Fault (SAF). Based on the in situ borehole measured stress data, using the method of 3D dynamic faulting analysis, we quantitatively determine the regional normal stress, shear stress, and friction coefficient at various seismogenic depths. These new data indicate that the southern SAF is a weak fault within the depth of 15 km. As depth increases, all the regional normal and shear stresses and friction coefficient increase. The former two increase faster than the latter. Regional shear stress increment per kilometer equals 5.75 ± 0.05 MPa/km for depth ≤15 km; regional normal stress increment per kilometer is equal to 25.3 ± 0.1 MPa/km for depth ≤15 km. As depth increases, regional friction coefficient increment per kilometer decreases rapidly from 0.08 to 0.01/km at depths less than ~3 km. As depth increases from ~3 to ~5 km, it is 0.01/km and then from ~5 to 15 km, and it is 0.002/km. Previously, frictional strength could be qualitatively determined by heat flow measurements. It is difficult to obtain the quantitative heat flow data for the SAF because the measured heat flow data exhibit large scatter. However, our quantitative results of frictional strength can be employed to investigate the heat flow in the southern SAF. We use a physical quantity P f to describe heat flow. It represents the dissipative friction heat power per unit area generated by the relative motion of two tectonic plates accommodated by off-fault deformation. P f is called "fault friction heat." On the basis of our determined frictional strength data, utilizing the method of 3D dynamic faulting analysis, we quantitatively determine the regional long-term fault

Vegetation - San Felipe Valley [ds172

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California Natural Resource Agency — This Vegetation Map of the San Felipe Valley Wildlife Area in San Diego County, California is based on vegetation samples collected in the field in 2002 and 2005 and...

El urbanismo de Santiago de Compostela : un plano con las plazuelas de San Martín y de San Miguel de 1709

Directory of Open Access Journals (Sweden)

Miguel Taín Guzmán

1998-01-01

Full Text Available El presente artículo está dedicado al estudio de un plano inédito de 1709 donde se representan las plazuelas de San Martín y de San Miguel, en el barrio intramuros de la Puerta de la Peña de Santiago de Compostela. Gracias al referido dibujo, analizo al detalle el entramado urbano de ambos espacios públicos y los edificios que los delimitan, particularmente la iglesia de San Martín Pinario, el desaparecido Palacio del Tribunal de la Santa Inquisición y la iglesia parroquial de San Miguel dos Agros.The article focuses on the study of a 1709 inpublished street plan of two squares —San Martín and San Miguel— in the Puerta de la Peña quarter (Santiago de Compostela. This oíd drawing shows the urban framework of both public spaces and also the buildings around: San Martín Pinario, the lost Palacio del Tribunal de la Santa Inquisición and the paroquial church of San Miguel de los Agros.

78 FR 57482 - Safety Zone; America's Cup Aerobatic Box, San Francisco Bay, San Francisco, CA

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2013-09-19

...-AA00 Safety Zone; America's Cup Aerobatic Box, San Francisco Bay, San Francisco, CA AGENCY: Coast Guard... America's Cup air shows. These safety zones are established to provide a clear area on the water for... announced by America's Cup Race Management. ADDRESSES: Documents mentioned in this preamble are part of...

77 FR 42649 - Safety Zone: Sea World San Diego Fireworks, Mission Bay; San Diego, CA

Science.gov (United States)

2012-07-20

... 1625-AA00 Safety Zone: Sea World San Diego Fireworks, Mission Bay; San Diego, CA AGENCY: Coast Guard... authorized by the Captain of the Port, or his designated representative. DATES: This rule is effective from 8... to ensure the public's safety. B. Basis and Purpose The Ports and Waterways Safety Act gives the...

The disappearing San of southeastern Africa and their genetic affinities.

Science.gov (United States)

Schlebusch, Carina M; Prins, Frans; Lombard, Marlize; Jakobsson, Mattias; Soodyall, Himla

2016-12-01

Southern Africa was likely exclusively inhabited by San hunter-gatherers before ~2000 years ago. Around that time, East African groups assimilated with local San groups and gave rise to the Khoekhoe herders. Subsequently, Bantu-speaking farmers, arriving from the north (~1800 years ago), assimilated and displaced San and Khoekhoe groups, a process that intensified with the arrival of European colonists ~350 years ago. In contrast to the western parts of southern Africa, where several Khoe-San groups still live today, the eastern parts are largely populated by Bantu speakers and individuals of non-African descent. Only a few scattered groups with oral traditions of Khoe-San ancestry remain. Advances in genetic research open up new ways to understand the population history of southeastern Africa. We investigate the genomic variation of the remaining individuals from two South African groups with oral histories connecting them to eastern San groups, i.e., the San from Lake Chrissie and the Duma San of the uKhahlamba-Drakensberg. Using ~2.2 million genetic markers, combined with comparative published data sets, we show that the Lake Chrissie San have genetic ancestry from both Khoe-San (likely the ||Xegwi San) and Bantu speakers. Specifically, we found that the Lake Chrissie San are closely related to the current southern San groups (i.e., the Karretjie people). Duma San individuals, on the other hand, were genetically similar to southeastern Bantu speakers from South Africa. This study illustrates how genetic tools can be used to assess hypotheses about the ancestry of people who seemingly lost their historic roots, only recalling a vague oral tradition of their origin.

Prediction of maximum earthquake intensities for the San Francisco Bay region

Science.gov (United States)

Borcherdt, Roger D.; Gibbs, James F.

1975-01-01

The intensity data for the California earthquake of April 18, 1906, are strongly dependent on distance from the zone of surface faulting and the geological character of the ground. Considering only those sites (approximately one square city block in size) for which there is good evidence for the degree of ascribed intensity, the empirical relation derived between 1906 intensities and distance perpendicular to the fault for 917 sites underlain by rocks of the Franciscan Formation is: Intensity = 2.69 - 1.90 log (Distance) (km). For sites on other geologic units intensity increments, derived with respect to this empirical relation, correlate strongly with the Average Horizontal Spectral Amplifications (AHSA) determined from 99 three-component recordings of ground motion generated by nuclear explosions in Nevada. The resulting empirical relation is: Intensity Increment = 0.27 +2.70 log (AHSA), and average intensity increments for the various geologic units are -0.29 for granite, 0.19 for Franciscan Formation, 0.64 for the Great Valley Sequence, 0.82 for Santa Clara Formation, 1.34 for alluvium, 2.43 for bay mud. The maximum intensity map predicted from these empirical relations delineates areas in the San Francisco Bay region of potentially high intensity from future earthquakes on either the San Andreas fault or the Hazard fault.

Prediction of maximum earthquake intensities for the San Francisco Bay region

Energy Technology Data Exchange (ETDEWEB)

Borcherdt, R.D.; Gibbs, J.F.

1975-01-01

The intensity data for the California earthquake of Apr 18, 1906, are strongly dependent on distance from the zone of surface faulting and the geological character of the ground. Considering only those sites (approximately one square city block in size) for which there is good evidence for the degree of ascribed intensity, the empirical relation derived between 1906 intensities and distance perpendicular to the fault for 917 sites underlain by rocks of the Franciscan formation is intensity = 2.69 - 1.90 log (distance) (km). For sites on other geologic units, intensity increments, derived with respect to this empirical relation, correlate strongly with the average horizontal spectral amplifications (AHSA) determined from 99 three-component recordings of ground motion generated by nuclear explosions in Nevada. The resulting empirical relation is intensity increment = 0.27 + 2.70 log (AHSA), and average intensity increments for the various geologic units are -0.29 for granite, 0.19 for Franciscan formation, 0.64 for the Great Valley sequence, 0.82 for Santa Clara formation, 1.34 for alluvium, and 2.43 for bay mud. The maximum intensity map predicted from these empirical relations delineates areas in the San Francisco Bay region of potentially high intensity from future earthquakes on either the San Andreas fault or the Hayward fault.

75 FR 27432 - Security Zone; Golden Guardian 2010 Regional Exercise; San Francisco Bay, San Francisco, CA

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2010-05-17

... can better evaluate its effects on them and participate in the rulemaking process. Small businesses... DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 165 [Docket No. USCG-2010-0221] RIN 1625-AA87 Security Zone; Golden Guardian 2010 Regional Exercise; San Francisco Bay, San Francisco, CA AGENCY...

Three-Dimensional Investigation of a 5 m Deflected Swale along the San Andreas Fault in the Carrizo Plain

KAUST Repository

Akciz, S. O.; Ludwig, L. G.; Zielke, Olaf; Arrowsmith, J. R.

2014-01-01

Topographic maps produced from Light Detection and Ranging (LiDAR) data are useful for paleoseismic and neotectonic research because they provide submeter representation of faulting-related surface features. Offset measurements of geomorphic features, made in the field or on a remotely sensed imagery, commonly assume a straight or smooth (i.e., undeflected) pre-earthquake geometry. Here, we present results from investigation of an ∼20 cm deep and >5 m wide swale with a sharp bend along the San Andreas fault (SAF) at the Bidart fan site in the Carrizo Plain, California. From analysis of LiDAR topography images and field measurements, the swale was initially interpreted as a channel tectonically offset ∼4:7 m. Our observations from exposures in four backhoe excavations and 25 hand-dug trenchettes show that even though a sharp bend in the swale coincides with the trace of the A.D. 1857 fault rupture, the swale formed after the 1857 earthquake and was not tectonically offset. Subtle fractures observed within a surficial gravel unit overlying the 1857 rupture trace are similar to fractures previously documented at the Phelan fan and LY4 paleoseismic sites 3 and 35 km northwest of Bidart fan, respectively. Collectively, the fractures suggest that a post-1857 moderate-magnitude earthquake caused ground cracking in the Carrizo and Cholame stretches of the SAF. Our observations emphasize the importance of excavation at key locations to validate remote and ground-based measurements, and we advocate more geomorphic characterization for each site if excavation is not possible.

A reevaluation of the Pallett Creek earthquake chronology based on new AMS radiocarbon dates, San Andreas fault, California

Science.gov (United States)

Scharer, K.M.; Biasi, G.P.; Weldon, R.J.

2011-01-01

The Pallett Creek paleoseismic record occupies a keystone position in most attempts to develop rupture histories for the southern San Andreas fault. Previous estimates of earthquake ages at Pallett Creek were determined by decay counting radiocarbon methods. That method requires large samples which can lead to unaccounted sources of uncertainty in radiocarbon ages because of the heterogeneous composition of organic layers. In contrast, accelerator mass spectrometry (AMS) radiocarbon dates may be obtained from small samples that have known carbon sources and also allow for a more complete sampling of the section. We present 65 new AMS radiocarbon dates that span nine ground-rupturing earthquakes at Pallett Creek. Overall, the AMS dates are similar to and reveal no dramatic bias in the conventional dates. For many layers, however, individual charcoal samples were younger than the conventional dates, leading to earthquake ages that are overall slightly younger than previously reported. New earthquake ages are determined by Bayesian refinement of the layer ages based on stratigraphic ordering and sedimentological constraints. The new chronology is more regular than previously published records in large part due to new samples constraining the age of event R. The closed interval from event C to 1857 has a mean recurrence of 135years (?? = 83.2 years) and a quasiperiodic coefficient of variation (COV) of 0.61. We show that the new dates and resultant earthquake chronology have a stronger effect on COV than the specific membership of this long series and dating precision improvements from sedimentation rates. Copyright 2011 by the American Geophysical Union.

Helium measurements of pore fluids obtained from the San Andreas Fault Observatory at Depth (SAFOD, USA) drill cores

Science.gov (United States)

Ali, S.; Stute, M.; Torgersen, T.; Winckler, G.; Kennedy, B. M.

2011-02-01

4He accumulated in fluids is a well established geochemical tracer used to study crustal fluid dynamics. Direct fluid samples are not always collectable; therefore, a method to extract rare gases from matrix fluids of whole rocks by diffusion has been adapted. Helium was measured on matrix fluids extracted from sandstones and mudstones recovered during the San Andreas Fault Observatory at Depth (SAFOD) drilling in California, USA. Samples were typically collected as subcores or from drillcore fragments. Helium concentration and isotope ratios were measured 4-6 times on each sample, and indicate a bulk 4He diffusion coefficient of 3.5 ± 1.3 × 10-8 cm2 s-1 at 21°C, compared to previously published diffusion coefficients of 1.2 × 10-18 cm2 s-1 (21°C) to 3.0 × 10-15 cm2 s-1 (150°C) in the sands and clays. Correcting the diffusion coefficient of 4Hewater for matrix porosity (˜3%) and tortuosity (˜6-13) produces effective diffusion coefficients of 1 × 10-8 cm2 s-1 (21°C) and 1 × 10-7 (120°C), effectively isolating pore fluid 4He from the 4He contained in the rock matrix. Model calculations indicate that <6% of helium initially dissolved in pore fluids was lost during the sampling process. Complete and quantitative extraction of the pore fluids provide minimum in situ porosity values for sandstones 2.8 ± 0.4% (SD, n = 4) and mudstones 3.1 ± 0.8% (SD, n = 4).

Three-Dimensional Investigation of a 5 m Deflected Swale along the San Andreas Fault in the Carrizo Plain

KAUST Repository

Akciz, S. O.

2014-10-21

Topographic maps produced from Light Detection and Ranging (LiDAR) data are useful for paleoseismic and neotectonic research because they provide submeter representation of faulting-related surface features. Offset measurements of geomorphic features, made in the field or on a remotely sensed imagery, commonly assume a straight or smooth (i.e., undeflected) pre-earthquake geometry. Here, we present results from investigation of an ∼20 cm deep and >5 m wide swale with a sharp bend along the San Andreas fault (SAF) at the Bidart fan site in the Carrizo Plain, California. From analysis of LiDAR topography images and field measurements, the swale was initially interpreted as a channel tectonically offset ∼4:7 m. Our observations from exposures in four backhoe excavations and 25 hand-dug trenchettes show that even though a sharp bend in the swale coincides with the trace of the A.D. 1857 fault rupture, the swale formed after the 1857 earthquake and was not tectonically offset. Subtle fractures observed within a surficial gravel unit overlying the 1857 rupture trace are similar to fractures previously documented at the Phelan fan and LY4 paleoseismic sites 3 and 35 km northwest of Bidart fan, respectively. Collectively, the fractures suggest that a post-1857 moderate-magnitude earthquake caused ground cracking in the Carrizo and Cholame stretches of the SAF. Our observations emphasize the importance of excavation at key locations to validate remote and ground-based measurements, and we advocate more geomorphic characterization for each site if excavation is not possible.

Toxic phytoplankton in San Francisco Bay

Science.gov (United States)

Rodgers, Kristine M.; Garrison, David L.; Cloern, James E.

1996-01-01

The Regional Monitoring Program (RMP) was conceived and designed to document the changing distribution and effects of trace substances in San Francisco Bay, with focus on toxic contaminants that have become enriched by human inputs. However, coastal ecosystems like San Francisco Bay also have potential sources of naturally-produced toxic substances that can disrupt food webs and, under extreme circumstances, become threats to public health. The most prevalent source of natural toxins is from blooms of algal species that can synthesize metabolites that are toxic to invertebrates or vertebrates. Although San Francisco Bay is nutrient-rich, it has so far apparently been immune from the epidemic of harmful algal blooms in the world’s nutrient-enriched coastal waters. This absence of acute harmful blooms does not imply that San Francisco Bay has unique features that preclude toxic blooms. No sampling program has been implemented to document the occurrence of toxin-producing algae in San Francisco Bay, so it is difficult to judge the likelihood of such events in the future. This issue is directly relevant to the goals of RMP because harmful species of phytoplankton have the potential to disrupt ecosystem processes that support animal populations, cause severe illness or death in humans, and confound the outcomes of toxicity bioassays such as those included in the RMP. Our purpose here is to utilize existing data on the phytoplankton community of San Francisco Bay to provide a provisional statement about the occurrence, distribution, and potential threats of harmful algae in this Estuary.

ASTER Flyby of San Francisco

Science.gov (United States)

2002-01-01

The Advanced Spaceborne Thermal Emission and Reflection radiometer, ASTER, is an international project: the instrument was supplied by Japan's Ministry of International Trade and Industry. A joint US/Japan science team developed algorithms for science data products, and is validating instrument performance. With its 14 spectral bands, extremely high spatial resolution, and 15 meter along-track stereo capability, ASTER is the zoom lens of the Terra satellite. The primary mission goals are to characterize the Earth's surface; and to monitor dynamic events and processes that influence habitability at human scales. ASTER's monitoring and mapping capabilities are illustrated by this series of images of the San Francisco area. The visible and near infrared image reveals suspended sediment in the bays, vegetation health, and details of the urban environment. Flying over San Francisco (3.2MB) (high-res (18.3MB)), we see the downtown, and shadows of the large buildings. Past the Golden Gate Bridge and Alcatraz Island, we cross San Pablo Bay and enter Suisun Bay. Turning south, we fly over the Berkeley and Oakland Hills. Large salt evaporation ponds come into view at the south end of San Francisco Bay. We turn northward, and approach San Francisco Airport. Rather than landing and ending our flight, we see this is as only the beginning of a 6 year mission to better understand the habitability of the world on which we live. For more information: ASTER images through Visible Earth ASTER Web Site Image courtesy of MITI, ERSDAC, JAROS, and the U.S./Japan ASTER Science Team

The Effect of Bangpungtongsung-san Extracts on Adipocyte Metabolism

Directory of Open Access Journals (Sweden)

Sang Min, Lee

2008-03-01

Full Text Available Objective : The purpose of this study is to investigate the effects of Bangpungtongsung-san extracts on the preadipocytes proliferation, of 3T3-L1 cell line. lipolysis of adipocytes in rat's epididymis and localized fat accumulation of porcine by extraction methods(alcohol and water. Methods : Diminish 3T3-L1 proliferation and lipogenesis do primary role to reduce obesity. So, 3T3-L1 preadipocyte and adipocytes were performed on cell cultures, and using Sprague-Dawley rats for the lipogenesis, and treated with 0.01-1 ㎎/㎖ Bangpungtongsung-san Extracts depend on concentrations. Porcine skin including fat tissue after treated Bangpungtongsung-san Extracts by means of the dosage dependent variation are investigated the histologic changes after injection of these extracts. Results : Following results were obtained from the 3T3-L1 preadipocyte proliferation and lipolysis of adipocyte in rats and histologic investigation of fat tissue. 1. Bangpungtongsung-san extracts were showed the effect of decreased preadipocyte proliferation on the high dosage(1.0㎎/㎖. 2. Bangpungtongsung-san extracts were showed the effect of decreased the activity of glycerol-3-phosphate dehydrogenase(GPDH on the high dosage(1.0㎎/㎖ and Specially, alcohol extract of Bangpungtongsung -san was clear as time goes by high concentration. 3. Bangpungtongsung-san extracts were showed tries to compare the effect of lipolysis, alcohol extract of Bangpungtongsung-san on the high dosage(1.0㎎/㎖ was observed the effect is higher than water extract. 4. Investigated the histological changes in porcine fat tissue after treated Bangpungtongsung-san extracts, we knew that water extract of Bangpungtongsung-san was showed the effect of lipolysis on the high dosage(10.0㎎/㎖ and alcohol extract of Bangpungtongsung-san was showed significant activity to the lysis of cell membranes in all concentration. Conclusion : These results suggest that Bangpungtongsung-san extracts efficiently

SANS studies of polymers

International Nuclear Information System (INIS)

Wignall, G.D.

1984-10-01

Before small-angle neutron scattering (SANS), chain conformation studies were limited to light and small angle x-ray scattering techniques, usually in dilute solution. SANS from blends of normal and labeled molecules could give direct information on chain conformation in bulk polymers. Water-soluble polymers may be examined in H 2 O/D 2 O mixtures using contrast variation methods to provide further information on polymer structure. This paper reviews some of the information provided by this technique using examples of experiments performed at the National Center for Small-Angle Scattering Research (NCSASR)

Modeling pesticide loadings from the San Joaquin watershed into the Sacramento-San Joaquin Delta using SWAT

Science.gov (United States)

Chen, H.; Zhang, M.

2016-12-01

The Sacramento-San Joaquin Delta is an ecologically rich, hydrologically complex area that serves as the hub of California's water supply. However, pesticides have been routinely detected in the Delta waterways, with concentrations exceeding the benchmark for the protection of aquatic life. Pesticide loadings into the Delta are partially attributed to the San Joaquin watershed, a highly productive agricultural watershed located upstream. Therefore, this study aims to simulate pesticide loadings to the Delta by applying the Soil and Water Assessment Tool (SWAT) model to the San Joaquin watershed, under the support of the USDA-ARS Delta Area-Wide Pest Management Program. Pesticide use patterns in the San Joaquin watershed were characterized by combining the California Pesticide Use Reporting (PUR) database and GIS analysis. Sensitivity/uncertainty analyses and multi-site calibration were performed in the simulation of stream flow, sediment, and pesticide loads along the San Joaquin River. Model performance was evaluated using a combination of graphic and quantitative measures. Preliminary results indicated that stream flow was satisfactorily simulated along the San Joaquin River and the major eastern tributaries, whereas stream flow was less accurately simulated in the western tributaries, which are ephemeral small streams that peak during winter storm events and are mainly fed by irrigation return flow during the growing season. The most sensitive parameters to stream flow were CN2, SOL_AWC, HRU_SLP, SLSUBBSN, SLSOIL, GWQMN and GW_REVAP. Regionalization of parameters is important as the sensitivity of parameters vary significantly spatially. In terms of evaluation metric, NSE tended to overrate model performance when compared to PBIAS. Anticipated results will include (1) pesticide use pattern analysis, (2) calibration and validation of stream flow, sediment, and pesticide loads, and (3) characterization of spatial patterns and temporal trends of pesticide yield.

Butterfly fauna in Mount Gariwang-san, Korea

Directory of Open Access Journals (Sweden)

Cheol Min Lee

2016-06-01

Full Text Available The aim of this study is to elucidate butterfly fauna in Mt. Gariwang-san, Korea. A field survey was conducted from 2010 to 2015 using the line transect method. A literature survey was also conducted. A total of 2,037 butterflies belonging to 105 species were recorded. In the estimation of species richness of butterfly, 116 species were estimated to live in Mt. Gariwang-san. In butterfly fauna in Mt. Gariwang-san, the percentage of northern species was very high and the percentage of grassland species was relatively higher than that of forest edge species and forest interior species. Sixteen red list species were found. In particular, Mimathyma nycteis was only recorded in Mt. Gariwang-san. When comparing the percentage of northern species and southern species including those recorded in previous studies, the percentage of northern species was found to have decreased significantly whereas that of southern species increased. We suggest that the butterfly community, which is distributed at relatively high altitudes on Mt. Gariwang-san, will gradually change in response to climate change.

Distribution and demography of San Francisco gartersnakes (Thamnophis sirtalis tetrataenia) at Mindego Ranch, Russian Ridge Open Space Preserve, San Mateo County, California

Science.gov (United States)

Kim, Richard; Halstead, Brian J.; Wylie, Glenn D.; Casazza, Michael L.

2018-04-26

San Francisco gartersnakes (Thamnophis sirtalis tetrataenia) are a subspecies of common gartersnakes endemic to the San Francisco Peninsula of northern California. Because of habitat loss and collection for the pet trade, San Francisco gartersnakes were listed as endangered under the precursor to the Federal Endangered Species Act. A population of San Francisco gartersnakes resides at Mindego Ranch, San Mateo County, which is part of the Russian Ridge Open Space Preserve owned and managed by the Midpeninsula Regional Open Space District (MROSD). Because the site contained non-native fishes and American bullfrogs (Lithobates catesbeianus), MROSD implemented management to eliminate or reduce the abundance of these non-native species in 2014. We monitored the population using capture-mark-recapture techniques to document changes in the population during and following management actions. Although drought confounded some aspects of inference about the effects of management, prey and San Francisco gartersnake populations generally increased following draining of Aquatic Feature 3. Continued management of the site to keep invasive aquatic predators from recolonizing or increasing in abundance, as well as vegetation management that promotes heterogeneous grassland/shrubland near wetlands, likely would benefit this population of San Francisco gartersnakes.

San Francisco Bay Long Term Management Strategy for Dredging

Science.gov (United States)

The San Francisco Bay Long Term Management Strategy (LTMS) is a cooperative effort to develop a new approach to dredging and dredged material disposal in the San Francisco Bay area. The LTMS serves as the Regional Dredging Team for the San Francisco area.

San Juan Uchucuanicu: évolution historique

Directory of Open Access Journals (Sweden)

1975-01-01

Full Text Available La communauté de San Juan est reconnue depuis 1939. Une première partie concerne l’organisation de la reducción de San Juan vers le milieu du XVIe siècle. Le poids fiscal s’exerce durement sur le village et la crise est générale dans toute la vallée du Chancay au XVIIe. siècle. La christianisation des habitants est définitive au milieu de ce même siècle. C’est vers la fin du XVIIe siècle et durant tout le XVIIIe que se multiplient les conflits entre San Juan et les villages voisins liés aux terrains de pâture et à la possession de l’eau. La deuxième partie du travail concerne les rapports de la communauté de San Juan avec le Pérou contemporain : contrainte fiscale toujours très lourde durant la fin de l’époque coloniale, exactions des militaires juste avant l’indépendance. La période républicaine voit toujours les conflits avec les villages voisins mais aussi la naissance de familles qui cherchent à retirer le maximum de la communauté. Les terres sont divisées et attribuées : la détérioration de l’organisation communale traditionnelle est manifeste. L4es conflits se multiplient entre petits propriétaires, mais aussi avec les haciendas voisines : c’est l’apparition d’une véritable lutte de classes. La situation actuelle est incertaine, le poids de l’économie marchande se développe avec l’exode des jeunes. Que sera la communauté San Juan à la fin de ce siècle? La comunidad de San Juan está reconocida desde 1939. La primera parte concierne a la organización de la 'reducción' de San Juan hacia mediados del siglo XVI. El peso fiscal se ejerce duramente sobre el pueblo y en el siglo XVII la crisis es general en todo el valle de Chancay. Hacia mediados del mismo siglo la cristianización de los habitantes es definitiva. Es hacia fines del siglo XVII y durante todo el siglo XVIII que se multiplican los conflictos entre San Juan y los pueblos vecinos, los que están relacionados con los terrenos de

Quaternary geology of Alameda County, and parts of Contra Costa, Santa Clara, San Mateo, San Francisco, Stanislaus, and San Joaquin counties, California: a digital database

Science.gov (United States)

Helley, E.J.; Graymer, R.W.

1997-01-01

Alameda County is located at the northern end of the Diablo Range of Central California. It is bounded on the north by the south flank of Mount Diablo, one of the highest peaks in the Bay Area, reaching an elevation of 1173 meters (3,849 ft). San Francisco Bay forms the western boundary, the San Joaquin Valley borders it on the east and an arbitrary line from the Bay into the Diablo Range forms the southern boundary. Alameda is one of the nine Bay Area counties tributary to San Francisco Bay. Most of the country is mountainous with steep rugged topography. Alameda County is covered by twenty-eight 7.5' topographic Quadrangles which are shown on the index map. The Quaternary deposits in Alameda County comprise three distinct depositional environments. One, forming a transgressive sequence of alluvial fan and fan-delta facies, is mapped in the western one-third of the county. The second, forming only alluvial fan facies, is mapped in the Livermore Valley and San Joaquin Valley in the eastern part of the county. The third, forming a combination of Eolian dune and estuarine facies, is restricted to the Alameda Island area in the northwestern corner of the county.

San Francisco Bay Water Quality Improvement Fund

Science.gov (United States)

EPAs grant program to protect and restore San Francisco Bay. The San Francisco Bay Water Quality Improvement Fund (SFBWQIF) has invested in 58 projects along with 70 partners contributing to restore wetlands, water quality, and reduce polluted runoff.,

Development of 40m SANS and Its Utilization Techniques

International Nuclear Information System (INIS)

Choi, Sung Min; Kim, Tae Hwan

2010-06-01

Small angle neutron scattering (SANS) has been a very powerful tool to study nanoscale (1-100 nm) bulk structures in various materials such as polymer, self assembled materials, nano-porous materials, nano-magnetic materials, metal and ceramics. Understanding the importance of the SANS instrument, the 8m SANS instrument was installed at the CN beam port of HANARO in 2001. However, without having a cold neutron source, the beam intensity is fairly low and the Q-range is rather limited due to short instrument length. In July 1, 2003, therefore, the HANARO cold neutron research facility project was launched and a state of the art 40m SANS instrument was selected as top-priority instrument. The development of the 40m SANS instrument was completed as a joint project between Korea Advanced Institute of Science and Technology and the HANARO in 2010. Here, we report the specification of a state of art 40m SANS instrument at HANARO

San Diego's High School Dropout Crisis

Science.gov (United States)

Wilson, James C.

2012-01-01

This article highlights San Diego's dropout problem and how much it's costing the city and the state. Most San Diegans do not realize the enormous impact high school dropouts on their city. The California Dropout Research Project, located at the University of California at Santa Barbara, has estimated the lifetime cost of one class or cohort of…

Constraints on Friction, Dilatancy, Diffusivity, and Effective Stress From Low-Frequency Earthquake Rates on the Deep San Andreas Fault

Science.gov (United States)

Beeler, N. M.; Thomas, Amanda; Bürgmann, Roland; Shelly, David

2018-01-01

Families of recurring low-frequency earthquakes (LFEs) within nonvolcanic tremor on the San Andreas Fault in central California are sensitive to tidal stresses. LFEs occur at all levels of the tides, are strongly correlated and in phase with the 200 Pa shear stresses, and weakly and not systematically correlated with the 2 kPa tidal normal stresses. We assume that LFEs are small sources that repeatedly fail during shear within a much larger scale, aseismically slipping fault zone and consider two different models of the fault slip: (1) modulation of the fault slip rate by the tidal stresses or (2) episodic slip, triggered by the tides. LFEs are strongly clustered with duration much shorter than the semidiurnal tide; they cannot be significantly modulated on that time scale. The recurrence times of clusters, however, are many times longer than the semidiurnal, leading to an appearance of tidal triggering. In this context we examine the predictions of laboratory-observed triggered frictional (dilatant) fault slip. The undrained end-member model produces no sensitivity to the tidal normal stress, and slip onsets are in phase with the tidal shear stress. The tidal correlation constrains the diffusivity to be less than 1 × 10-6/s and the product of the friction and dilatancy coefficients to be at most 5 × 10-7, orders of magnitude smaller than observed at room temperature. In the absence of dilatancy the effective normal stress at failure would be about 55 kPa. For this model the observations require intrinsic weakness, low dilatancy, and lithostatic pore fluid.

Coal exploration in the Alto San Jorge area, Cordoba Department. Exploracion de carbones en el Ato San Jorge, Departamento de Cordoba

Energy Technology Data Exchange (ETDEWEB)

Ospina, L H; Oquendo, G G [Geominas Ltda, Medellin (Colombia)

1989-01-01

A Mining Feasibility Study in the Area of Alto San Jorge, Department of Cordoba, Colombia, was commissioned by CARBOCOL S.A. to the Consortium Geominas-NACI. An area of 800 Ka2 was explored to define surface mining possibilities within two subareas referred to as Alto San Jorge and San Pedro Ure. Rocks of Cretaceous, Tertiary and Quaternary age crop out in the zone. In the subarea Alto San Jorge the principal structure is a syncline with a south-north direction. The San Pedro Ure subarea is formed by undulations with flanks of low dip, the most important being the San Antonio Syncline because it contains the mining block. The geological study of the surface demonstrated the existence of coal in the Oligocene Cienaga de Oro Formation and the Niocene Cerrito Formation, with potential resources of 6.3 billion tons. The subsequent exploration of the subsoil, with 20.618 m of drilling, permitted determination of demonstrated reserves in the order of 2.9 billion tons within two areas. In the sector selected for the mine plan, in the area of San Pedro-Puerto Libertador, 7.791 m of drilling was accomplished to define a demonstrated reserve of 515 million tons of coal down to a depth of 200. The combustible type coal has 5.000 cal/g. Complete mining schedules were developed at the prefeasibility level for two surface mines with productions of 1.5 MMTY and 4 MMTY. 9 figs., 3 tabs., 28 refs.

Cenobios leoneses altomedievales ante la europeización: San Pedro y San Pablo de Montes, Santiago y San Martín de Peñalba y San Miguel de Escalada

Directory of Open Access Journals (Sweden)

Martínez Tejera, Artemio Manuel

2002-06-01

Full Text Available The following paper analyses the behaviour of three of the most important monastic communities in the reing of Asturias-Leon for the ninth and then centuries. During this period we witness the implementation of a new ordo, or liturgical ritual that replaces the Hispanic one, strongly established in the Territorium. The liturgical adaptation produces tension and conflicts among the members of different monastic communities, and even between the Episcopate and the monarchy - being King Alfonso VI. In some of the monasteries, the arrival of the new ordo causes the adaptation of the liturgical space, with subsequent changes in liturgical furniture.

El presente estudio pretende analizar el comportamiento de tres de las más importantes comunidades monásticas astur-leonesas de los siglos IX y X (San Pedro y San Pablo de Montes, Santiago y San Martín de Peñalba y San Miguel de Escalada ante la recepción e implantación de aquel nuevo ordo o ritual litúrgico que vino a sustituir al Hispánico, fuertemente asentado en el territorium. Readaptación litúrgica que, con distinta intensidad, producirá tensiones y enfrentamientos entre los miembros de las distintas comunidades monásticas, incluso entre el episcopado y la monarquía (personificada en la figura de Alfonso VI, pero no únicamente. En alguno de estos monasterios la llegada del nuevo ordo supondrá, además, la readaptación de su espacio litúrgico, lo que trajo consigo significativas modificaciones constructivas.

75 FR 6218 - New Melones Lake Area Resource Management Plan, Tuolumne and Calaveras Counties, CA

Science.gov (United States)

2010-02-08

..., CA 95222. Calaveras Planning Department, Calaveras County Government Center, 891 Mountain Ranch Road, San Andreas, CA 95249. San Andreas Central Library, 1299 Gold Hunter Road, San Andreas, CA 95249...

The Elizabeth Lake paleoseismic site: Rupture pattern constraints for the past ~800 years for the Mojave section of the south-central San Andreas Fault

Science.gov (United States)

Bemis, Sean; Scharer, Katherine M.; Dolan, James F.; Rhodes, Ed

2016-01-01

The southern San Andreas Fault in California has hosted two historic surface-rupturing earthquakes, the ~M7 1812 Wrightwood earthquake and the ~M7.9 1857 Fort Tejon earthquake (e.g., Sieh, 1978; Jacoby et al., 1988). Numerous paleoseismic studies have established chronologies of historic and prehistoric earthquakes at sites along the full length of the 1857 rupture (e.g., Sieh, 1978; Scharer et al., 2014). These studies provide an unparalleled opportunity to examine patterns of recent ruptures; however, at least two significant spatial gaps in high-quality paleoseismic sites remain. At ~100 km long each, these gaps contribute up to 100 km of uncertainty to paleo-rupture lengths and could also permit a surface rupture from an earthquake up to ~M7.2 to go undetected [using scaling relationships of Wells and Coppersmith (1994)]. Given the known occurrence of an ~M7 earthquake on this portion of the SAF (1812), it is critical to fill these gaps in order to better constrain paleo-rupture lengths and to increase the probability of capturing the full spatial record of surface rupturing earthquakes.   In this study, we target a new site within the 100 km long stretch of the San Andreas Fault between the Frazier Mountain and Pallett Creek paleoseismic sites (Figure 1), near Elizabeth Lake, California. Prior excavations at the site during 1998-1999 encountered promising stratigraphy but these studies were hindered by shallow groundwater throughout the site. We began our current phase of investigations in 2012, targeting the northwestern end of a 40 x 350 m fault-parallel depression that defines the site (Figure 2). Subsequent investigations in 2013 and 2014 focused on the southeastern end of the depression where the fault trace is constrained between topographic highs and is proximal to an active drainage. In total, our paleoseismic investigations consist of 10 fault-perpendicular trenches that cross the depression (Figure 2) and expose a >2000 year depositional record

77 FR 46115 - Notice of Inventory Completion: San Diego Museum of Man, San Diego, CA

Science.gov (United States)

2012-08-02

...The San Diego Museum of Man has completed an inventory of human remains in consultation with the appropriate Indian tribe, and has determined that there is a cultural affiliation between the human remains and a present-day Indian tribe. Representatives of any Indian tribe that believes itself to be culturally affiliated with the human remains may contact the San Diego Museum of Man. Repatriation of the human remains to the Indian tribe stated below may occur if no additional claimants come forward.

Effects of Choto-san and Chotoko on thiopental-induced sleeping time

OpenAIRE

JEENAPONGSA, Rattima; Tohda, Michihisa; Watanabe, Hiroshi

2003-01-01

Choto-san has been used for treatment of centrally regulated disorders such as dementia, hypertension, headache and vertigo. Our laboratory showed that Choto-san improved learning memory in ischemic mice. It is noticeable that Choto-san treated animals and animals that underwent conducting occlusion of common carotid arteries (2VO) operation slept longer than the normal animals. Therefore, this study aimed to clarify the effects of Choto-san and its related component; Chotoko and Choto-san wi...

33 CFR 110.120 - San Luis Obispo Bay, Calif.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false San Luis Obispo Bay, Calif. 110... ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.120 San Luis Obispo Bay, Calif. (a) Area A-1. Area A-1 is the water area bounded by the San Luis Obispo County wharf, the shoreline, a line drawn...

Species Observations (poly) - San Diego County [ds648

Data.gov (United States)

California Natural Resource Agency — Created in 2009, the SanBIOS database serves as a single repository of species observations collected by various departments within the County of San Diego's Land...

Mammal Track Counts - San Diego County [ds442

Data.gov (United States)

California Natural Resource Agency — The San Diego Tracking Team (SDTT) is a non-profit organization dedicated to promoting the preservation of wildlife habitat in San Diego County through citizen-based...

Species Observations (poly) - San Diego County [ds648

Data.gov (United States)

California Department of Resources — Created in 2009, the SanBIOS database serves as a single repository of species observations collected by various departments within the County of San Diego's Land...

Biological and associated water-quality data for lower Olmos Creek and upper San Antonio River, San Antonio, Texas, March-October 1990

Science.gov (United States)

Taylor, R. Lynn

1995-01-01

Biological and associated water-quality data were collected from lower Olmos Creek and upper San Antonio River in San Antonio, Texas, during March-October 1990, the second year of a multiyear data-collection program. The data will be used to document water-quality conditions prior to implementation of a proposal to reuse treated wastewater to irrigate city properties in Olmos Basin and Brackenridge Parks and to augment flows in the Olmos Creek/San Antonio River system.

Remembering San Diego

International Nuclear Information System (INIS)

Chuyanov, V.

1999-01-01

After 6 years of existence the ITER EDA project in San Diego, USA, was terminated by desition of the US Congress. This article describes how nice it was for everybody as long as it lasted and how sad it is now

Vabariigi aastapäev San Franciscos / Heino Valvur ; foto: Heino Valvur

Index Scriptorium Estoniae

Valvur, Heino

2006-01-01

veebruarikuu möödus San Franciscos Eesti Vabariigi 88. aastapäeva pühitsedes: traditsiooniliselt tähistas aastapäeva San Francisco Seenioride Klubi koosviibimisega, E.E.L.K. San Francisco koguduses peeti jumalateenistus ja koosviibimine, kus noored esitasid rahvalaule, San Francisco Eesti Selts tähistas aastapäeva 25. veebruaril aktuse ja koosviibimisega

76 FR 70480 - Otay River Estuary Restoration Project, South San Diego Bay Unit of the San Diego Bay National...

Science.gov (United States)

2011-11-14

... River Estuary Restoration Project, South San Diego Bay Unit of the San Diego Bay National Wildlife...), intend to prepare an environmental impact statement (EIS) for the proposed Otay River Estuary Restoration... any one of the following methods. Email: [email protected] . Please include ``Otay Estuary NOI'' in the...

Constraints on Shallow Crustal Structure across the San Andreas Fault Zone, Coachella Valley, Southern California: Results from the Salton Seismic Imaging Project (SSIP)

Science.gov (United States)

Hernandez, A.; Persaud, P.; Bauer, K.; Stock, J. M.; Fuis, G. S.; Hole, J. A.; Goldman, M.

2015-12-01

The strong influence of basin structure and crustal heterogeneities on seismic wave propagation suggests that these factors should be included in calculations of strong ground shaking. Knowledge of the shallow subsurface is thus essential for an accurate seismic hazard estimate for the densely populated Coachella Valley, the region north of the potential M7.8 rupture near the Salton Sea. Using SSIP data, we analyzed first arrivals from nine 65-911 kg explosive shots recorded along a profile in the Coachella Valley in order to evaluate the interpretation of our 2D tomographic results and give added details on the structural complexity of the shallow crust. The line extends 37 km from the Peninsular Ranges to the Little San Bernardino Mountains crossing the major strands of the San Andreas Fault Zone. We fit traveltime curves to our picks with forward modeling ray tracing, and determined 1D P-wave velocity models for traveltime arrivals east and west of each shot, and a 2D model for the line. We also inferred the geometry of near-vertical faults from the pre-stack line migration method of Bauer et al. (2013). In general, the 1D models east of individual shots have deeper basement contacts and lower apparent velocities, ~5 km/s at 4 km depth, whereas the models west of individual shots have shallower basement and velocities up to 6 km/s at 2 km depth. Mismatches in basement depths (assuming 5-6 km/s) between individual 1D models indicate a shallowly dipping basement, deepening eastward towards the Banning Fault and shoaling abruptly farther east. An east-dipping structure in the 2D model also gives a better fit than horizontal layers. Based on high velocity zones derived from traveltimes at 9-20 km from the western end of the line, we included an offset from ~2 km to 4 km depth near the middle of the line, which significantly improved the 2D model fit. If fault-related, this offset could represent the Garnet Hill Fault if it continues southward in the subsurface.

Backwater Flooding in San Marcos, TX from the Blanco River

Science.gov (United States)

Earl, Richard; Gaenzle, Kyle G.; Hollier, Andi B.

2016-01-01

Large sections of San Marcos, TX were flooded in Oct. 1998, May 2015, and Oct. 2015. Much of the flooding in Oct. 1998 and Oct. 2015 was produced by overbank flooding of San Marcos River and its tributaries by spills from upstream dams. The May 2015 flooding was almost entirely produced by backwater flooding from the Blanco River whose confluence is approximately 2.2 miles southeast of downtown. We use the stage height of the Blanco River to generate maps of the areas of San Marcos that are lower than the flood peaks and compare those results with data for the observed extent of flooding in San Marcos. Our preliminary results suggest that the flooding occurred at locations more than 20 feet lower than the maximum stage height of the Blanco River at San Marcos gage (08171350). This suggest that the datum for either gage 08171350 or 08170500 (San Marcos River at San Marcos) or both are incorrect. There are plans for the U.S. Army Corps of Engineers to construct a Blanco River bypass that will divert Blanco River floodwaters approximately 2 miles farther downstream, but the $60 million price makes its implementation problematic.

33 CFR 165.1187 - Security Zones; Golden Gate Bridge and the San Francisco-Oakland Bay Bridge, San Francisco Bay...

Science.gov (United States)

2010-07-01

... Limited Access Areas Eleventh Coast Guard District § 165.1187 Security Zones; Golden Gate Bridge and the... Golden Gate Bridge and the San Francisco-Oakland Bay Bridge, in San Francisco Bay, California. (b... siren, radio, flashing light, or other means, the operator of a vessel shall proceed as directed. [COTP...

Fitting the datum of SANS with Pxy program

International Nuclear Information System (INIS)

Sun, Liangwei; Peng, Mei; Chen, Liang

2009-04-01

The thesis introduces the basic theory of Small-Angle neutron scattering, enumerates several approximate law. It simply describes the components of Small-Angle neutron spectrometer (SANS) and the parameters of SANS of Budapest Neutron Center (BNC) in Hungary. During the period of studying at Budapest Neutron Center in Hungary, the experiments of wavelength calibration was carried out with SIBE and the SANS experiments of sample Micelles. The experiments are briefly introduced. Pxy program is used to fit these datum, and the results of wavelength and sizes of sample Micelles are presented. (authors)

City of San Francisco, California street tree resource analysis

Science.gov (United States)

E.G. McPherson; J.R. Simpson; P.J. Peper; Q. Xiao

2004-01-01

Street trees in San Francisco are comprised of two distinct populations, those managed by the city’s Department of Public Works (DPW) and those managed by private property owners with or without the help of San Francisco’s urban forestry nonprofit, Friends of the Urban Forest (FUF). These two entities believe that the public’s investment in stewardship of San Francisco...

Trouble Brewing in San Francisco. Policy Brief

Science.gov (United States)

Buck, Stuart

2010-01-01

The city of San Francisco will face enormous budgetary pressures from the growing deficits in public pensions, both at a state and local level. In this policy brief, the author estimates that San Francisco faces an aggregate $22.4 billion liability for pensions and retiree health benefits that are underfunded--including $14.1 billion for the city…

77 FR 66499 - Environmental Impact Statement: San Bernardino and Los Angeles Counties, CA

Science.gov (United States)

2012-11-05

... San Bernardino, 285 East Hospitality Lane, San Bernardino, California 92408 (2) Sheraton Ontario..., November 13, 2012 from 5-7 p.m. at the Hilton San Bernardino, 285 East Hospitality Lane, San Bernardino...

33 CFR 110.74c - Bahia de San Juan, PR.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Bahia de San Juan, PR. 110.74c Section 110.74c Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.74c Bahia de San Juan, PR. The waters of San Antonio...

San Francisco Accelerator Conference

International Nuclear Information System (INIS)

Southworth, Brian

1991-01-01

'Where are today's challenges in accelerator physics?' was the theme of the open session at the San Francisco meeting, the largest ever gathering of accelerator physicists and engineers

Trouble Brewing in San Diego. Policy Brief

Science.gov (United States)

Buck, Stuart

2010-01-01

The city of San Diego will face enormous budgetary pressures from the growing deficits in public pensions, both at a state and local level. In this policy brief, the author estimates that San Diego faces total of $45.4 billion, including $7.95 billion for the county pension system, $5.4 billion for the city pension system, and an estimated $30.7…

Corps sans organes et anamnèse

DEFF Research Database (Denmark)

Wilson, Alexander

2011-01-01

Je trace certains liens entre le corps sans organes de Deleuze et Guattari et les principes de l’organologie générale que décrit Bernard Stiegler.......Je trace certains liens entre le corps sans organes de Deleuze et Guattari et les principes de l’organologie générale que décrit Bernard Stiegler....

Coastal Cactus Wren, San Diego Co. - 2009 [ds702

Data.gov (United States)

California Natural Resource Agency — The San Diego Multiple Species Conservation program (MSCP) was developed for the conservation of plants and animals in the southeast portion of San Diego County....

Coastal Cactus Wren, San Diego Co. - 2011 [ds708

Data.gov (United States)

California Natural Resource Agency — The San Diego Multiple Species Conservation program (MSCP) was developed for the conservation of plants and animals in the southeast portion of San Diego County....

Cacao use and the San Lorenzo Olmec

Science.gov (United States)

Powis, Terry G.; Cyphers, Ann; Gaikwad, Nilesh W.; Grivetti, Louis; Cheong, Kong

2011-01-01

Mesoamerican peoples had a long history of cacao use—spanning more than 34 centuries—as confirmed by previous identification of cacao residues on archaeological pottery from Paso de la Amada on the Pacific Coast and the Olmec site of El Manatí on the Gulf Coast. Until now, comparable evidence from San Lorenzo, the premier Olmec capital, was lacking. The present study of theobromine residues confirms the continuous presence and use of cacao products at San Lorenzo between 1800 and 1000 BCE, and documents assorted vessels forms used in its preparation and consumption. One elite context reveals cacao use as part of a mortuary ritual for sacrificial victims, an event that occurred during the height of San Lorenzo's power. PMID:21555564

100 Years of Accumulated Deformation at Depth Observed in the Elizabeth Lake Tunnel, Southern San Andreas Fault

Science.gov (United States)

Telling, J. W.; Tayyebi, A.; Hudnut, K. W.; Davis, C. A.; Glennie, C. L.

2017-12-01

The Elizabeth Lake Tunnel was completed in 1911 to convey water from the Owens Valley to Los Angeles, CA. The tunnel is approximately 8-km long and crosses the San Andreas Fault (SAF) at a depth of 90 m below the surface, measured near the tunnel mid-point. If present, a tectonic signal recorded by warping or offset of this tunnel could provide an opportunity to examine the deformation at depth in this location during the 100 years since the tunnel was constructed. A temporary closure of the tunnel for inspection and repair allowed the entire 8-km length to be surveyed using terrestrial laser scanning, providing a complete high-resolution 3D model of the tunnel. Since a high-resolution survey of the tunnel after its construction is not available for comparison, we assume that the tunnel was originally straight; this assumption is substantiated by records that indicate that the two halves of the tunnel, dug from opposite ends, met within 2.9 cm in the XY-plane and 1.6 cm in the Z-direction, at an off-fault location. Our results show 20 cm of right-lateral horizontal deformation near the estimated location of the tunnel's intersection with SAF, which agrees with the SAF sense of motion. The zone of deviation is approximately 300 m south of the SAF surface trace, and is about 350 m south of where the two tunneling crews met. This observed offset is consistent with either steady-state creep of about 2 mm/yr or possibly residual afterslip following the 1857 earthquake (that may be negligible at present). The full tectonic strain accumulation at this location would be five to ten times higher than observed, so clearly the observed deformation is only part of the expected full tectonic signal. In addition to the 20 cm short-wavelength deflection, we are examining for possible subtle longer wavelength deformation of the tunnel. The lidar model also shows significantly higher density of apparent cracking in the tunnel walls near this intercept point.

Mammal Track Counts - San Diego County, 2010 [ds709

Data.gov (United States)

California Natural Resource Agency — The San Diego Tracking Team (SDTT) is a non-profit organization dedicated to promoting the preservation of wildlife habitat in San Diego County through citizen-based...

SANS observations on weakly flocculated dispersions

DEFF Research Database (Denmark)

Mischenko, N.; Ourieva, G.; Mortensen, K.

1997-01-01

Structural changes occurring in colloidal dispersions of poly-(methyl metacrylate) (PMMA) particles, sterically stabilized with poly-(12-hydroxystearic acid) (PHSA), while varying the solvent quality, temperature and shear rate, are investigated by small-angle neutron scattering (SANS......). For a moderately concentrated dispersion in a marginal solvent the transition on cooling from the effective stability to a weak attraction is monitored, The degree of attraction is determined in the framework of the sticky spheres model (SSM), SANS and rheological results are correlated....

Short-period strain (0.1-105 s): Near-source strain field for an earthquake (M L 3.2) near San Juan Bautista, California

Science.gov (United States)

Johnston, M. J. S.; Borcherdt, R. D.; Linde, A. T.

1986-10-01

Measurements of dilational earth strain in the frequency band 25-10-5 Hz have been made on a deep borehole strainmeter installed near the San Andreas fault. These data are used to determine seismic radiation fields during nuclear explosions, teleseisms, local earthquakes, and ground noise during seismically quiet times. Strains of less than 10-10 on these instruments can be clearly resolved at short periods (< 10 s) and are recorded with wide dynamic range digital recorders. This permits measurement of the static and dynamic strain variations in the near field of local earthquakes. Noise spectra for earth strain referenced to 1 (strain)2/Hz show that strain resolution decreases at about 10 dB per decade of frequency from -150 dB at 10-4 Hz to -223 dB at 10 Hz. Exact expressions are derived to relate the volumetric strain and displacement field for a homogeneous P wave in a general viscoelastic solid as observed on colocated dilatometers and seismometers. A rare near-field recording of strain and seismic velocity was obtained on May 26, 1984, from an earthquake (ML 3.2) at a hypocentral distance of 3.2 km near the San Andreas fault at San Juan Bautista, California. While the data indicate no precursory strain release at the 5 × 10-11 strain level, a coseismic strain release of 1.86 nanostrain was observed. This change in strain is consistent with that calculated from a simple dislocation model of the event. Ground displacement spectra, determined from the downhole strain data and instrument-corrected surface seismic data, suggest that source parameters estimated from surface recordings may be contaminated by amplification effects in near-surface low-velocity materials.

SANS-II at SINQ: Installation of the former Risø-SANS facility

DEFF Research Database (Denmark)

Strunz, P.; Mortensen, K.; Janssen, S.

2004-01-01

SANS-II facility at SINQ (Paul Scherrer Institute)-the reinstalled former Riso small-angle neutron scattering instrument-is presented. Its operational characteristics are listed. Approaches for precise determination of wavelength, detector dead time and attenuation factors are described as well. (C...

Precise Relative Location of San Andreas Fault Tremors Near Cholame, CA, Using Seismometer Clusters: Slip on the Deep Extension of the Fault?

Science.gov (United States)

Shelly, D. R.; Ellsworth, W. L.; Ryberg, T.; Haberland, C.; Fuis, G.; Murphy, J.; Nadeau, R.; Bürgmann, R.

2008-12-01

Non-volcanic tremor, similar in character to that generated at some subduction zones, was recently identified beneath the strike-slip San Andreas Fault (SAF) in central California (Nadeau and Dolenc, 2005). Using a matched filter method, we closely examine a 24-hour period of active SAF tremor and show that, like tremor in the Nankai Trough subduction zone, this tremor is composed of repeated similar events. We take advantage of this similarity to locate detected similar events relative to several chosen events. While low signal-to-noise makes location challenging, we compensate for this by estimating event-pair differential times at 'clusters' of nearby temporary and permanent stations rather than at single stations. We find that the relative locations consistently form a near-linear structure in map view, striking parallel to the surface trace of the SAF. Therefore, we suggest that at least a portion of the tremor occurs on the deep extension of the fault, similar to the situation for subduction zone tremor. Also notable is the small depth range (a few hundred meters or less) of many of the located tremors, a feature possibly analogous to earthquake streaks observed on the shallower portion of the fault. The close alignment of the tremor with the SAF slip orientation suggests a shear slip mechanism, as has been argued for subduction tremor. At times, we observe a clear migration of the tremor source along the fault, at rates of 15-40 km/hr.

Marketing San Juan Basin gas

International Nuclear Information System (INIS)

Posner, D.M.

1988-01-01

Marketing natural gas produced in the San Juan Basin of New Mexico and Colorado principally involves four gas pipeline companies with significant facilities in the basin. The system capacity, transportation rates, regulatory status, and market access of each of these companies is evaluated. Because of excess gas supplies available to these pipeline companies, producers can expect improved take levels and prices by selling gas directly to end users and utilities as opposed to selling gas to the pipelines for system supply. The complexities of transporting gas today suggest that the services of an independent gas marketing company may be beneficial to smaller producers with gas supplies in the San Juan Basin

Transformation and reconstitution of Khoe-San identities : AAS le Fleur I, Griqua identities and post-apartheid Khoe-San revivalism (1894-2004)

NARCIS (Netherlands)

Besten, M.P.

2006-01-01

Focussing on AAS le fleur I (1867-1941), the Griqua, and post-apartheid Khoe-San revivalism, the dissertation examines changes in the articulation of Khoe-San identities in South-Africa. It shows the significance of shifting political, cultural and ideological power relations on the articulation of

Imaging San Jacinto Fault damage zone structure using dense linear arrays: application of ambient noise tomography, Rayleigh wave ellipticity, and site amplification

Science.gov (United States)

Wang, Y.; Lin, F. C.; Allam, A. A.; Ben-Zion, Y.

2017-12-01

The San Jacinto fault is presently the most seismically active component of the San Andreas Transform system in Southern California. To study the damage zone structure, two dense linear geophone arrays (BS and RR) were deployed across the Clark segment of the San Jacinto Fault between Anza and Hemet during winter 2015 and Fall 2016, respectively. Both arrays were 2 km long with 20 m station spacing. Month-long three-component ambient seismic noise data were recorded and used to calculate multi-channel cross-correlation functions. All three-component noise records of each array were normalized simultaneously to retain relative amplitude information between different stations and different components. We observed clear Rayleigh waves and Love waves on the cross-correlations of both arrays at 0.3 - 1 s period. The phase travel times of the Rayleigh waves on both arrays were measured by frequency-time analysis (FTAN), and inverted for Rayleigh wave phase velocity profiles of the upper 500 m depth. For both arrays, we observe prominent asymmetric low velocity zones which narrow with depth. At the BS array near the Hemet Stepover, an approximately 250m wide slow zone is observed to be offset by 75m to the northeast of the surface fault trace. At the RR array near the Anza segment of the fault, a similar low velocity zone width and offset are observed, along with a 10% across-fault velocity contrast. Analyses of Rayleigh wave ellipticity (H/V ratio), Love wave phase travel times, and site amplification are in progress. By using multiple measurements from ambient noise cross-correlations, we can obtain strong constraints on the local damage zone structure of the San Jacinto Fault. The results contribute to improved understanding of rupture directivity, maximum earthquake magnitude and more generally seismic hazard associated with the San Jacinto fault zone.

Geological literature on the San Joaquin Valley of California

Science.gov (United States)

Maher, J.C.; Trollman, W.M.; Denman, J.M.

1973-01-01

The following list of references includes most of the geological literature on the San Joaquin Valley and vicinity in central California (see figure 1) published prior to January 1, 1973. The San Joaquin Valley 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.

75 FR 61611 - Modification of Class E Airspace; San Clemente, CA

Science.gov (United States)

2010-10-06

... INFORMATION CONTACT: Eldon Taylor, Federal Aviation Administration, Operations Support Group, Western Service... extension to a Class D surface area, at San Clemente Island NALF (Fredrick Sherman Field), San Clemente, CA... within the scope of that authority as it amends controlled airspace at San Clemente Island NALF (Fredrick...

Petrogenesis of cataclastic rocks within the San Andreas fault zone of Southern California U.S.A.

Science.gov (United States)

Lawford Anderson, J.; Osborne, Robert H.; Palmer, Donald F.

1980-08-01

This paper petrologically characterizes cataclastic rocks derived from four sites within the San Andreas fault zone of southern California. In this area, the fault traverses an extensive plutonic and metamorphic terrane and the principal cataclastic rock formed at these upper crustal levels is unindurated gouge derived from a range of crystalline rocks including diorite, tonalite, granite, aplite, and pegmatite. The mineralogical nature of this gouge is decidedly different from the "clay gouge" reported by Wu (1975) for central California and is essentially a rock flour with a quartz, feldspar, biotite, chlorite, amphibole, epidote and oxide mineralogy representing the milled-down equivalent of the original rock. Clay development is minor (less than 4 wt. %) to nonexistent and is exclusively kaolinite. Alterations involve hematitic oxidation, chlorite alteration on biotite and amphibole, and local introduction of calcite. Electron microprobe analysis showed that in general the major minerals were not reequilibrated with the pressure—temperature regime imposed during cataclasis. Petrochemically, the form of cataclasis that we have investigated is largely an isochemical process. Some hydration occurs but the maximum amount is less than 2.2% added H 2O. Study of a 375 m deep core from a tonalite pluton adjacent to the fault showed that for Si, Al, Ti, Fe, Mg, Mn, K, Na, Li, Rb, and Ba, no leaching and/or enrichment occurred. Several samples experienced a depletion in Sr during cataclasis while lesser number had an enrichment of Ca (result of calcite veining). Texturally, the fault gouge is not dominated by clay-size material but consists largely of silt and fine sand-sized particles. An intriguing aspect of our work on the drill core is a general decrease in particulate size with depth (and confining pressure) with the predominate shifting sequentially from fine sand to silt-size material. The original fabric of these rocks is commonly not disrupted during the

Velocity Gradient Across the San Andreas Fault and Changes in Slip Behavior as Outlined by Full non Linear Tomography

Science.gov (United States)

Chiarabba, C.; Giacomuzzi, G.; Piana Agostinetti, N.

2017-12-01

The San Andreas Fault (SAF) near Parkfield is the best known fault section which exhibit a clear transition in slip behavior from stable to unstable. Intensive monitoring and decades of studies permit to identify details of these processes with a good definition of fault structure and subsurface models. Tomographic models computed so far revealed the existence of large velocity contrasts, yielding physical insight on fault rheology. In this study, we applied a recently developed full non-linear tomography method to compute Vp and Vs models which focus on the section of the fault that exhibit fault slip transition. The new tomographic code allows not to impose a vertical seismic discontinuity at the fault position, as routinely done in linearized codes. Any lateral velocity contrast found is directly dictated by the data themselves and not imposed by subjective choices. The use of the same dataset of previous tomographic studies allows a proper comparison of results. We use a total of 861 earthquakes, 72 blasts and 82 shots and the overall arrival time dataset consists of 43948 P- and 29158 S-wave arrival times, accurately selected to take care of seismic anisotropy. Computed Vp and Vp/Vs models, which by-pass the main problems related to linarized LET algorithms, excellently match independent available constraints and show crustal heterogeneities with a high resolution. The high resolution obtained in the fault surroundings permits to infer lateral changes of Vp and Vp/Vs across the fault (velocity gradient). We observe that stable and unstable sliding sections of the SAF have different velocity gradients, small and negligible in the stable slip segment, but larger than 15 % in the unstable slip segment. Our results suggest that Vp and Vp/Vs gradients across the fault control fault rheology and the attitude of fault slip behavior.

77 FR 34984 - Notice of Intent To Repatriate a Cultural Item: San Diego Museum of Man, San Diego, CA

Science.gov (United States)

2012-06-12

...The San Diego Museum of Man, in consultation with the appropriate Indian tribes, has determined that a cultural item meets the definition of unassociated funerary object and repatriation to the Indian tribes stated below may occur if no additional claimants come forward. Representatives of any Indian tribe that believes itself to be culturally affiliated with the cultural item may contact the San Diego Museum of Man.

40 CFR 81.176 - San Luis Intrastate Air Quality Control Region.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 17 2010-07-01 2010-07-01 false San Luis Intrastate Air Quality Control Region. 81.176 Section 81.176 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Quality Control Regions § 81.176 San Luis Intrastate Air Quality Control Region. The San Luis Intrastate...

L’Europe et les sans-papiers

OpenAIRE

Simonnot, Nathalie; Intrand, Caroline

2013-01-01

En Europe, les sans-papiers vivent des conditions socio-économiques particulièrement défavorables. Les systèmes de santé des pays européens sont peu performants pour le suivi des personnes sans papiers. Ils sont en outre souvent victimes de refus de soins. Pire, l’accès aux soins est dans certains pays progressivement instrumentalisé au profit du contrôle de l’immigration. Ces politiques grossissent les rangs des populations qui n’accèdent pas aux soins et doivent avoir recours à Médecins du ...

Voice and Valency in San Luis Potosi Huasteco

Science.gov (United States)

Munoz Ledo Yanez, Veronica

2014-01-01

This thesis presents an analysis of the system of transitivity, voice and valency alternations in Huasteco of San Luis Potosi (Mayan) within a functional-typological framework. The study is based on spoken discourse and elicited data collected in the municipalities of Aquismon and Tancanhuitz de Santos in the state of San Luis Potosi, Mexico. The…

Timber resource statistics for the San Joaquin and southern resource areas of California.

Science.gov (United States)

Karen L. Waddell; Patricia M. Bassett

1997-01-01

This report is a summary of timber resource statistics for the San Joaquin and Southern Resource Areas of California, which include Alpine, Amador, Calaveras, Fresno, Imperial, Inyo, Kern, Kings, Los Angeles, Madera, Mariposa, Merced, Mono, Orange, Riverside, San Bernardino, San Diego, San Joaquin, Stanislaus, Tulare, and Tuolumne Counties. Data were collected as part...

The green areas of San Juan, Puerto Rico

Directory of Open Access Journals (Sweden)

Olga M. Ramos-González

2014-09-01

Full Text Available Green areas, also known as green infrastructure or urban vegetation, are vital to urbanites for their critical roles in mitigating urban heat island effects and climate change and for their provision of multiple ecosystem services and aesthetics. Here, I provide a high spatial resolution snapshot of the green cover distribution of the city of San Juan, Puerto Rico, by incorporating the use of morphological spatial pattern analysis (MSPA as a tool to describe the spatial pattern and connectivity of the city's urban green areas. Analysis of a previously developed IKONOS 4-m spatial resolution classification of the city of San Juan from 2002 revealed a larger area of vegetation (green areas or green infrastructure than previously estimated by moderate spatial resolution imagery. The city as a whole had approximately 42% green cover and 55% impervious surfaces. Although the city appeared greener in its southern upland sector compared to the northern coastal section, where most built-up urban areas occurred (66% impervious surfaces, northern San Juan had 677 ha more green area cover dispersed across the city than the southern component. MSPA revealed that most forest cover occurred as edges and cores, and green areas were most commonly forest cores, with larger predominance in the southern sector of the municipality. In dense, built-up, urban land, most of the green areas occurred in private yards as islets. When compared to other cities across the United States, San Juan was most similar in green cover features to Boston, Massachusetts, and Miami, Florida. Per capita green space for San Juan (122.2 m²/inhabitant was also comparable to these two U.S. cities. This study explores the intra-urban vegetation variation in the city of San Juan, which is generally overlooked by moderate spatial resolution classifications in Puerto Rico. It serves as a starting point for green infrastructure mapping and landscape pattern analysis of the urban green spaces

Sediment transport of streams tributary to San Francisco, San Pablo, and Suisun Bays, California, 1909-66

Science.gov (United States)

Porterfield, George

1980-01-01

A review of historical sedimentation data is presented, results of sediment-data collection for water years 1957-59 are summarized, and long-term sediment-discharge estimates from a preliminary report are updated. Comparison of results based on 3 years of data to those for the 10 water years, 1957-66, provides an indication of the adequacy of the data obtained during the short period to define the long-term relation between sediment transport and streamflow. During 1909-66, sediment was transported to the entire San Francisco Bay system at an average rate of 8.6 million cubic yards per year. The Sacramento and San Joaquin River basins provided about 83% of the sediment inflow to the system annually during 1957-66 and 86% during 1909-66. About 98% of this inflow was measured or estimated at sediment measuring sites. Measured sediment inflow directly to the bays comprised only about 40% of the total discharged by basins directly tributary to the bays. About 90% of the total sediment discharge to the delta and the bays in the San Francisco Bay system thus was determined on the basis of systematic measurements. (USGS)

Along-strike variations in fault frictional properties along the San Andreas Fault near Cholame, California from joint earthquake and low-frequency earthquake relocations

Science.gov (United States)

Harrington, Rebecca M.; Cochran, Elizabeth S.; Griffiths, Emily M.; Zeng, Xiangfang; Thurber, Clifford H.

2016-01-01

Recent observations of low‐frequency earthquakes (LFEs) and tectonic tremor along the Parkfield–Cholame segment of the San Andreas fault suggest slow‐slip earthquakes occur in a transition zone between the shallow fault, which accommodates slip by a combination of aseismic creep and earthquakes (fault, which accommodates slip by stable sliding (>35  km depth). However, the spatial relationship between shallow earthquakes and LFEs remains unclear. Here, we present precise relocations of 34 earthquakes and 34 LFEs recorded during a temporary deployment of 13 broadband seismic stations from May 2010 to July 2011. We use the temporary array waveform data, along with data from permanent seismic stations and a new high‐resolution 3D velocity model, to illuminate the fine‐scale details of the seismicity distribution near Cholame and the relation to the distribution of LFEs. The depth of the boundary between earthquakes and LFE hypocenters changes along strike and roughly follows the 350°C isotherm, suggesting frictional behavior may be, in part, thermally controlled. We observe no overlap in the depth of earthquakes and LFEs, with an ∼5  km separation between the deepest earthquakes and shallowest LFEs. In addition, clustering in the relocated seismicity near the 2004 Mw 6.0 Parkfield earthquake hypocenter and near the northern boundary of the 1857 Mw 7.8 Fort Tejon rupture may highlight areas of frictional heterogeneities on the fault where earthquakes tend to nucleate.

Three-dimensional magnetotelluric inversion in practice—the electrical conductivity structure of the San Andreas Fault in Central California

Science.gov (United States)

Tietze, Kristina; Ritter, Oliver

2013-10-01

3-D inversion techniques have become a widely used tool in magnetotelluric (MT) data interpretation. However, with real data sets, many of the controlling factors for the outcome of 3-D inversion are little explored, such as alignment of the coordinate system, handling and influence of data errors and model regularization. Here we present 3-D inversion results of 169 MT sites from the central San Andreas Fault in California. Previous extensive 2-D inversion and 3-D forward modelling of the data set revealed significant along-strike variation of the electrical conductivity structure. 3-D inversion can recover these features but only if the inversion parameters are tuned in accordance with the particularities of the data set. Based on synthetic 3-D data we explore the model space and test the impacts of a wide range of inversion settings. The tests showed that the recovery of a pronounced regional 2-D structure in inversion of the complete impedance tensor depends on the coordinate system. As interdependencies between data components are not considered in standard 3-D MT inversion codes, 2-D subsurface structures can vanish if data are not aligned with the regional strike direction. A priori models and data weighting, that is, how strongly individual components of the impedance tensor and/or vertical magnetic field transfer functions dominate the solution, are crucial controls for the outcome of 3-D inversion. If deviations from a prior model are heavily penalized, regularization is prone to result in erroneous and misleading 3-D inversion models, particularly in the presence of strong conductivity contrasts. A `good' overall rms misfit is often meaningless or misleading as a huge range of 3-D inversion results exist, all with similarly `acceptable' misfits but producing significantly differing images of the conductivity structures. Reliable and meaningful 3-D inversion models can only be recovered if data misfit is assessed systematically in the frequency

Creep avalanches on San Andreas Fault and their underlying mechanism from 19 years of InSAR and seismicity

Science.gov (United States)

Khoshmanesh, M.; Shirzaei, M.

2017-12-01

Recent seismic and geodetic observations indicate that interseismic creep rate varies in both time and space. The spatial extent of creep determines the earthquake potential, while its temporal evolution, known as slow slip events (SSE), may trigger earthquakes. Although the conditions promoting fault creep are well-established, the mechanism for initiating self-sustaining and sometimes cyclic creep events is enigmatic. Here we investigate a time series of 19 years of surface deformation measured by radar interferometry between 1992 and 2011 along the Central San Andreas Fault (CSAF) to constrain the temporal evolution of creep. We show that the creep rate along the CSAF has a sporadic behavior, quantified with a Gumbel-like probability distribution characterized by longer tail toward the extreme positive rates, which is signature of burst-like creep dynamics. Defining creep avalanches as clusters of isolated creep with rates exceeding the shearing rate of tectonic plates, we investigate the statistical properties of their size and length. We show that, similar to the frequency-magnitude distribution of seismic events, the distribution of potency estimated for creep avalanches along the CSAF follows a power law, dictated by the distribution of their along-strike lengths. We further show that an ensemble of concurrent creep avalanches which aseismically rupture isolated fault compartments form the semi-periodic SSEs observed along the CSAF. Using a rate and state friction model, we show that normal stress is temporally variable on the fault, and support this using seismic observations. We propose that, through a self-sustaining fault-valve behavior, compaction induced elevation of pore pressure within hydraulically isolated fault compartments, and subsequent frictional dilation is the cause for the observed episodic SSEs. We further suggest that the 2004 Parkfield Mw6 earthquake may have been triggered by the SSE on adjacent creeping segment, which increased Coulomb

Elemental Geochemistry of Samples From Fault Segments of the San Andreas Fault Observatory at Depth (SAFOD) Drill Hole

Science.gov (United States)

Tourscher, S. N.; Schleicher, A. M.; van der Pluijm, B. A.; Warr, L. N.

2006-12-01

Elemental geochemistry of mudrock samples from phase 2 drilling of the San Andreas Fault Observatory at Depth (SAFOD) is presented from bore hole depths of 3066 m to 3169 m and from 3292 m to 3368 m, which contain a creeping section and main trace of the fault, respectively. In addition to preparation and analysis of whole rock sample, fault grains with neomineralized, polished surfaces were hand picked from well-washed whole rock samples, minimizing the potential contamination from drilling mud and steel shavings. The separated fractions were washed in deionized water, powdered using a mortar and pestle, and analyzed using an Inductively Coupled Plasma- Optical Emission Spectrometer for major and minor elements. Based on oxide data results, systematic differences in element concentrations are observed between the whole rock and fault rock. Two groupings of data points are distinguishable in the regions containing the main trace of the fault, a shallow part (3292- 3316 m) and a deeper section (3320-3368 m). Applying the isocon method, assuming Zr and Ti to be immobile elements in these samples, indicates a volume loss of more than 30 percent in the shallow part and about 23 percent in the deep part of the main trace. These changes are minimum estimates of fault-related volume loss, because the whole rock from drilling samples contains variable amount of fault rock as well. Minimum estimates for volume loss in the creeping section of the fault are more than 50 percent when using the isocon method, comparing whole rock to plucked fault rock. The majority of the volume loss in the fault rocks is due to the dissolution and loss of silica, potassium, aluminum, sodium and calcium, whereas (based on oxide data) the mineralized surfaces of fractures appear to be enriched in Fe and Mg. The large amount of element mobility within these fault traces suggests extensive circulation of hydrous fluids along fractures that was responsible for progressive dissolution and leaching

Hydrologic assessment and numerical simulation of groundwater flow, San Juan Mine, San Juan County, New Mexico, 2010–13

Science.gov (United States)

Stewart, Anne M.

2018-04-03

Coal combustion byproducts (CCBs), which are composed of fly ash, bottom ash, and flue gas desulfurization material, produced at the coal-fired San Juan Generating Station (SJGS), located in San Juan County, New Mexico, have been buried in former surface-mine pits at the San Juan Mine, also referred to as the San Juan Coal Mine, since operations began in the early 1970s. This report, prepared by the U.S. Geological Survey in cooperation with the Mining and Minerals Division of the New Mexico Energy, Minerals and Natural Resources Department, describes results of a hydrogeologic assessment, including numerical groundwater modeling, to identify the timing of groundwater recovery and potential pathways for groundwater transport of metals that may be leached from stored CCBs and reach hydrologic receptors after operations cease. Data collected for the hydrologic assessment indicate that groundwater in at least one centrally located reclaimed surface-mining pit has already begun to recover.The U.S. Geological Survey numerical modeling package MODFLOW–NWT was used with MODPATH particle-tracking software to identify advective flow paths from CCB storage areas toward potential hydrologic receptors. Results indicate that groundwater at CCB storage areas will recover to the former steady state, or in some locations, groundwater may recover to a new steady state in 6,600 to 10,600 years at variable rates depending on the proximity to a residual cone-of-groundwater depression caused by mine dewatering and regional oil and gas pumping as well as on actual, rather than estimated, groundwater recharge and evapotranspirational losses. Advective particle-track modeling indicates that the number of particles and rates of advective transport will vary depending on hydraulic properties of the mine spoil, particularly hydraulic conductivity and porosity. Modeling results from the most conservative scenario indicate that particles can migrate from CCB repositories to either the

Effectiveness of Kampo medicine Gorei-san for chronic subdural hematoma

International Nuclear Information System (INIS)

Miyagami, Mitsusuke; Kagawa, Yukihide

2009-01-01

Chronic subdural hematomas (CSDHs) are basically treated by surgery. In some cases with no or minimum symptoms, however, they may be treated conservatively. In the present study, we evaluated the therapeutic effect of a Kampo medicine (Japanese traditional herbal medicine), Gorei-san, in the treatment of those CSDHs. Gorei-san 7.5 g t.i.d. was orally administered for 4 weeks in 22 patients with 27 CSDHs. Maximum thickness of the hematoma was followed up on CT scan for 4 to 29 weeks after administration of Gorei-san. In 7 of 22 patients, tranexamic acid and/or carbazochrome sodium sulfonate were also administrated. Gorei-san was effective in 23 of 27 CSDHs. In 12 of them, the hematoma was completely disappeared within 14 weeks after administration. In the other 11 CSDHs, the thickness was decreased. In those effective cases, thickness began to decrease 3 to 4 weeks after administration of Gorei-san. It was more effective in CSDHs with iso-/high or mixed density than with low density on CT. It was not effective in 4 out of 27 CSDHs. No apparent adverse effect was noted in the present series of patients. The present study suggests that a Kampo medicine, Gorei-san, is a useful option in the conservative treatment of CSDHs with no or minimum symptoms. (author)

75 FR 65985 - Safety Zone: Epic Roasthouse Private Party Firework Display, San Francisco, CA

Science.gov (United States)

2010-10-27

... the navigable waters of San Francisco Bay 1,000 yards off Epic Roasthouse Restaurant, San Francisco.... Wright, Program Manager, Docket Operations, telephone 202-366-9826. SUPPLEMENTARY INFORMATION: Regulatory... waters of San Francisco Bay, 1,000 yards off Epic Roasthouse Restaurant, San Francisco, CA. The fireworks...

Rupture Propagation through the Big Bend of the San Andreas Fault: A Dynamic Modeling Case Study of the Great Earthquake of 1857

Science.gov (United States)

Lozos, J.

2017-12-01

The great San Andreas Fault (SAF) earthquake of 9 January 1857, estimated at M7.9, was one of California's largest historic earthquakes. Its 360 km rupture trace follows the Carrizo and Mojave segments of the SAF, including the 30° compressional Big Bend in the fault. If 1857 were a characteristic rupture, the hazard implications for southern California would be dire, especially given the inferred 150 year recurrence interval for this section of the fault. However, recent paleoseismic studies in this region suggest that 1857-type events occur less frequently than single-segment Carrizo or Mojave ruptures, and that the hinge of the Big Bend is a barrier to through-going rupture. Here, I use 3D dynamic rupture modeling to attempt to reproduce the rupture length and surface slip distribution of the 1857 earthquake, to determine which physical conditions allow rupture to negotiate the Big Bend of the SAF. These models incorporate the nonplanar geometry of the SAF, an observation-based heterogeneous regional velocity structure (SCEC CVM), and a regional stress field from seismicity literature. Under regional stress conditions, I am unable to produce model events that both match the observed surface slip on the Carrizo and Mojave segments of the SAF and include rupture through the hinge of the Big Bend. I suggest that accumulated stresses at the bend hinge from multiple smaller Carrizo or Mojave ruptures may be required to allow rupture through the bend — a concept consistent with paleoseismic observations. This study may contribute to understanding the cyclicity of hazard associated with the southern-central SAF.

75 FR 42014 - Proposed Amendment of Class E Airspace; San Clemente, CA

Science.gov (United States)

2010-07-20

...: Eldon Taylor, Federal Aviation Administration, Operations Support Group, Western Service Center, 1601... an extension to a Class D surface area, at San Clemente Island NALF (Fredrick Sherman Field), San... Clemente Island NALF (Fredrick Sherman Field), CA (Lat. 33[deg]01'22'' N., long. 118[deg]35'19'' W.) San...

Imaging the Fine-Scale Structure of the San Andreas Fault in the Northern Gabilan Range with Explosion and Earthquake Sources

Science.gov (United States)

Xin, H.; Thurber, C. H.; Zhang, H.; Wang, F.

2014-12-01

A number of geophysical studies have been carried out along the San Andreas Fault (SAF) in the Northern Gabilan Range (NGR) with the purpose of characterizing in detail the fault zone structure. Previous seismic research has revealed the complex structure of the crustal volume in the NGR region in two-dimensions (Thurber et al., 1996, 1997), and there has been some work on the three-dimensional (3D) structure at a coarser scale (Lin and Roecker, 1997). In our study we use earthquake body-wave arrival times and differential times (P and S) and explosion arrival times (only P) to image the 3D P- and S-wave velocity structure of the upper crust along the SAF in the NGR using double-difference (DD) tomography. The earthquake and explosion data types have complementary strengths - the earthquake data have good resolution at depth and resolve both Vp and Vs structure, although only where there are sufficient seismic rays between hypocenter and stations, whereas the explosions contribute very good near-surface resolution but for P waves only. The original dataset analyzed by Thurber et al. (1996, 1997) included data from 77 local earthquakes and 8 explosions. We enlarge the dataset with 114 more earthquakes that occurred in the study area, obtain improved S-wave picks using an automated picker, and include absolute and cross-correlation differential times. The inversion code we use is the algorithm tomoDD (Zhang and Thurber, 2003). We assess how the P and S velocity models and earthquake locations vary as we alter the inversion parameters and the inversion grid. The new inversion results show clearly the fine-scale structure of the SAF at depth in 3D, sharpening the image of the velocity contrast from the southwest side to the northeast side.

Using a modified time-reverse imaging technique to locate low-frequency earthquakes on the San Andreas Fault near Cholame, California

Science.gov (United States)

Horstmann, Tobias; Harrington, Rebecca M.; Cochran, Elizabeth S.

2015-01-01

We present a new method to locate low-frequency earthquakes (LFEs) within tectonic tremor episodes based on time-reverse imaging techniques. The modified time-reverse imaging technique presented here is the first method that locates individual LFEs within tremor episodes within 5 km uncertainty without relying on high-amplitude P-wave arrivals and that produces similar hypocentral locations to methods that locate events by stacking hundreds of LFEs without having to assume event co-location. In contrast to classic time-reverse imaging algorithms, we implement a modification to the method that searches for phase coherence over a short time period rather than identifying the maximum amplitude of a superpositioned wavefield. The method is independent of amplitude and can help constrain event origin time. The method uses individual LFE origin times, but does not rely on a priori information on LFE templates and families.We apply the method to locate 34 individual LFEs within tremor episodes that occur between 2010 and 2011 on the San Andreas Fault, near Cholame, California. Individual LFE location accuracies range from 2.6 to 5 km horizontally and 4.8 km vertically. Other methods that have been able to locate individual LFEs with accuracy of less than 5 km have mainly used large-amplitude events where a P-phase arrival can be identified. The method described here has the potential to locate a larger number of individual low-amplitude events with only the S-phase arrival. Location accuracy is controlled by the velocity model resolution and the wavelength of the dominant energy of the signal. Location results are also dependent on the number of stations used and are negligibly correlated with other factors such as the maximum gap in azimuthal coverage, source–station distance and signal-to-noise ratio.

78 FR 42027 - Safety Zone; San Diego Bayfair; Mission Bay, San Diego, CA

Science.gov (United States)

2013-07-15

... safety zones. Thunderboats Unlimited Inc. is sponsoring San Diego Bayfair, which is held on the navigable... distribution of power and responsibilities between the Federal Government and Indian tribes. 12. Energy Effects This proposed rule is not a ``significant energy action'' under Executive Order 13211, Actions...

77 FR 60897 - Safety Zone: America's Cup World Series Finish-Line, San Francisco, CA

Science.gov (United States)

2012-10-05

... navigable waters of the San Francisco Bay in vicinity of San Francisco West Yacht Harbor Light 2... vicinity of San Francisco West Yacht Harbor Light 2. Unauthorized persons or vessels are prohibited from... San Francisco West Yacht Harbor Light 2. This safety zone establishes a temporary restricted area on...

San Juanico Hybrid System Technical and Institutional Assessment: Preprint

Energy Technology Data Exchange (ETDEWEB)

Corbus, D.; Newcomb, C.; Yewdall, Z.

2004-07-01

San Juanico is a fishing village of approximately 120 homes in the Municipality of Comondu, Baja California. In April, 1999, a hybrid power system was installed in San Juanico to provide 24-hour power, which was not previously available. Before the installation of the hybrid power system, a field study was conducted to characterize the electrical usage and institutional and social framework of San Juanico. One year after the installation of the hybrid power system a''post-electrification'' study was performed to document the changes that had occurred after the installation. In December of 2003, NREL visited the site to conduct a technical assessment of the system.

Steam, solarization, and tons of prevention: the San Francisco Public Utilities Commission's fight to contain Phytophthoras in San Francisco Bay area restoration sites

Science.gov (United States)

Greg Lyman; Jessica Appel; Mia Ingolia; Ellen Natesan; Joe Ortiz

2017-01-01

To compensate for unavoidable impacts associated with critical water infrastructure capital improvement projects, the San Francisco Public Utilities Commission (SFPUC) restored over 2,050 acres of riparian, wetland, and upland habitat on watershed lands in Alameda, Santa Clara, and San Mateo Counties. Despite strict bio-sanitation protocols, plant pathogens (...

Effects of Choto-san (Diao-Teng-San) on microcirculation of bulbar conjunctiva and hemorheological factors in patients with asymptomatic cerebral infarction

OpenAIRE

YANG, Qiao; Kita, Toshiaki; Hikiami, Hiroaki; Shimada, Yutaka; Itoh, Takashi; Terasawa, Katsutoshi

1999-01-01

In this study, the effects of Choto-san ( 釣藤散 ) on the microcirculation of bulbar conjunctiva in 16 patients with asymptornatic cerebral infarction were investigated with a video-microscopic system. After the administration of Choto-san for four weeks, variables of microcirculatory flow of the bulbar conjunctiva, that is, the internal diameter of vessels, flow velocity and flow volume rate were increased (p

Riparian Habitat - San Joaquin River

Data.gov (United States)

California Natural Resource Agency — The immediate focus of this study is to identify, describe and map the extent and diversity of riparian habitats found along the main stem of the San Joaquin River,...

Characterization of the San Andreas Fault near Parkfield, California by fault-zone trapped waves

Science.gov (United States)

Li, Y.; Vidale, J.; Cochran, E.

2003-04-01

In October, 2002, coordinated by the Pre-EarthScope/SAFOD, we conducted an extensive seismic experiment at the San Andreas fault (SAF), Parkfield to record fault-zone trapped waves generated by explosions and microearthquakes using dense linear seismic arrays of 52 PASSCAL 3-channel REFTEKs deployed across and along the fault zone. We detonated 3 explosions within and out of the fault zone during the experiment, and also recorded other 13 shots of PASO experiment of UWM/RPI (Thurber and Roecker) detonated around the SAFOD drilling site at the same time. We observed prominent fault-zone trapped waves with large amplitudes and long duration following S waves at stations close to the main fault trace for sources located within and close to the fault zone. Dominant frequencies of trapped waves are 2-3 Hz for near-surface explosions and 4-5 Hz for microearthquakes. Fault-zone trapped waves are relatively weak on the north strand of SAF for same sources. In contrast, seismograms registered for both the stations and shots far away from the fault zone show a brief S wave and lack of trapped waves. These observations are consistent with previous findings of fault-zone trapped waves at the SAF [Li et al., 1990; 1997], indicating the existence of a well-developed low-velocity waveguide along the main fault strand (principal slip plan) of the SAF. The data from denser arrays and 3-D finite-difference simulations of fault-zone trapped waves allowed us to delineate the internal structure, segmentation and physical properties of the SAF with higher resolution. The trapped-wave inferred waveguide on the SAF Parkfield segment is ~150 m wide at surface and tapers to ~100 m at seismogenic depth, in which Q is 20-50 and S velocities are reduced by 30-40% from wall-rock velocities, with the greater velocity reduction at the shallow depth and to southeast of the 1966 M6 epicenter. We interpret this low-velocity waveguide on the SAF main strand as being the remnant of damage zone caused

Neutron beam applications - Polymer study and sample environment development for HANARO SANS instrument

Energy Technology Data Exchange (ETDEWEB)

Kim, Hong Doo [Kyunghee University, Seoul (Korea); Char, Kook Heon [Seoul National University, Seoul (Korea)

2000-04-01

A new SANS instrument will be installed in HANARO reactor near future and in parallel it is necessary to develop the sample environment facilities. One of the basic items is the equipment to control the sample temperature of cell block with auto-sample changer. It is required to develop a control software for this purpose. In addition, softwares of the aquisition and analysis for SANS instrument must be developed and supplied in order to function properly. PS/PI block copolymer research in NIST will provide the general understanding of SANS instrument and instrument-related valuable informations such as standard sample for SANS and know-hows of the instrument building. The following are the results of this research. a. Construction of sample cell block. b. Software to control the temperature and auto-sample changer. c. Acquisition of the SANS data analysis routine and its modification for HANARO SANS. d. PS/PI block copolymer research in NIST. e. Calibration data of NIST and HANARO SANS for comparison. 39 figs., 2 tabs. (Author)

33 CFR 80.1130 - San Luis Obispo Bay, CA.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false San Luis Obispo Bay, CA. 80.1130 Section 80.1130 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1130 San Luis Obispo Bay, CA. A line drawn from...

A New Estimate for Total Offset on the Southern San Andreas Fault: Implications for Cumulative Plate Boundary Shear in the Northern Gulf of California

Science.gov (United States)

Darin, M. H.; Dorsey, R. J.

2012-12-01

Development of a consistent and balanced tectonic reconstruction for the late Cenozoic San Andreas fault (SAF) in southern California has been hindered for decades by incompatible estimates of total dextral offset based on different geologic cross-fault markers. The older estimate of 240-270 km is based on offset fluvial conglomerates of the middle Miocene Mint Canyon and Caliente Formations west of the SAF from their presumed source area in the northern Chocolate Mountains NE of the SAF (Ehlig et al., 1975; Ehlert, 2003). The second widely cited offset marker is a distinctive Triassic megaporphyritic monzogranite that has been offset 160 ± 10 km between Liebre Mountain west of the SAF and the San Bernadino Mountains (Matti and Morton, 1993). In this analysis we use existing paleocurrent data and late Miocene clockwise rotation in the eastern Transverse Ranges (ETR) to re-assess the orientation of the piercing line used in the 240 km-correlation, and present a palinspastic reconstruction that satisfies all existing geologic constraints. Our reconstruction of the Mint Canyon piercing line reduces the original estimate of 240-270 km to 195 ± 15 km of cumulative right-lateral slip on the southern SAF (sensu stricto), which is consistent with other published estimates of 185 ± 20 km based on correlative basement terranes in the Salton Trough region. Our estimate of ~195 km is consistent with the lower estimate of ~160 km on the Mojave segment because transform-parallel extension along the southwestern boundary of the ETR during transrotation produces ~25-40 km of displacement that does not affect offset markers of the Liebre/San Bernadino correlation located northwest of the ETR rotating domain. Reconciliation of these disparate estimates places an important new constraint on the total plate boundary shear that is likely accommodated in the adjacent northern Gulf of California. Global plate circuit models require ~650 km of cumulative Pacific-North America (PAC

San Antonio Bay 1986-1989

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The effect of salinity on utilization of shallow-water nursery habitats by aquatic fauna was assessed in San Antonio Bay, Texas. Overall, 272 samples were collected...

San Gregorio mining: general presentation of the enterprise

International Nuclear Information System (INIS)

1997-01-01

This work is a project presented by San Gregorio Mine.This company is responsible for the extraction and gold ore deposits benefits in San Gregorio and East extension in Minas de Corrales. For this project was carried out an environmental impact study as well as and agreement with the LATU for the laboratory analyzes and the surface and groundwater monitoring within the Environmental program established by the Company

Evaluating the Possibility of a joint San Andreas-Imperial Fault Rupture in the Salton Trough Region

Science.gov (United States)

Kyriakopoulos, C.; Oglesby, D. D.; Meltzner, A. J.; Rockwell, T. K.

2016-12-01

A geodynamic investigation of possible earthquakes in a given region requires both field data and numerical simulations. In particular, the investigation of past earthquakes is also a fundamental part of understanding the earthquake potential of the Salton Trough region. Geological records from paleoseismic trenches inform us of past ruptures (length, magnitude, timing), while dynamic rupture models allow us to evaluate numerically the mechanics of such earthquakes. The two most recent events (Mw 6.4 1940 and Mw 6.9 1979) on the Imperial fault (IF) both ruptured up to the northern end of the mapped fault, giving the impression that rupture doesn't propagate further north. This result is supported by small displacements, 20 cm, measured at the Dogwood site near the end of the mapped rupture in each event. However, 3D paleoseismic data from the same site corresponding to the most recent pre-1940 event (1710 CE) and 5th (1635 CE) and 6th events back revealed up to 1.5 m of slip in those events. Since we expect the surface displacement to decrease toward the termination of a rupture, we postulate that in these earlier cases the rupture propagated further north than in 1940 or 1979. Furthermore, paleoseismic data from the Coachella site (Philibosian et al., 2011) on the San Andreas fault (SAF) indicates slip events ca. 1710 CE and 1588-1662 CE. In other words, the timing of two large paleoseismic displacements on the IF cannot be distinguished from the timing of the two most recent events on the southern SAF, leaving a question: is it possible to have through-going rupture in the Salton Trough? We investigate this question through 3D dynamic finite element rupture modeling. In our work, we considered two scenarios: rupture initiated on the IF propagating northward, and rupture initiated on the SAF propagating southward. Initial results show that, in the first case, rupture propagates north of the mapped northern terminus of the IF only under certain pre

Estimating natural recharge in San Gorgonio Pass watersheds, California, 1913–2012

Science.gov (United States)

Hevesi, Joseph A.; Christensen, Allen H.

2015-12-21

A daily precipitation-runoff model was developed to estimate spatially and temporally distributed recharge for groundwater basins in the San Gorgonio Pass area, southern California. The recharge estimates are needed to define transient boundary conditions for a groundwater-flow model being developed to evaluate the effects of pumping and climate on the long-term availability of groundwater. The area defined for estimating recharge is referred to as the San Gorgonio Pass watershed model (SGPWM) and includes three watersheds: San Timoteo Creek, Potrero Creek, and San Gorgonio River. The SGPWM was developed by using the U.S. Geological Survey INFILtration version 3.0 (INFILv3) model code used in previous studies of recharge in the southern California region, including the San Gorgonio Pass area. The SGPWM uses a 150-meter gridded discretization of the area of interest in order to account for spatial variability in climate and watershed characteristics. The high degree of spatial variability in climate and watershed characteristics in the San Gorgonio Pass area is caused, in part, by the high relief and rugged topography of the area.

Timber resource statistics for the San Joaquin and southern California resource areas.

Science.gov (United States)

Bruce Hiserote; Joel Moen; Charles L. Bolsinger

1986-01-01

This report is one of five that provide timber resource statistics for 57 of the 58 counties in California (San Francisco is excluded). This report presents statistics from a 1982-84 inventory of the timber resources of Alpine, Amador, Calaveras, Fresno, Imperial, Inyo, Kern, Kings, Los Angeles, Madera, Mariposa, Merced, Mono, Orange, Riverside, San Bernardino, San...

Automatic identification of fault zone head waves and direct P waves and its application in the Parkfield section of the San Andreas Fault, California

Science.gov (United States)

Li, Zefeng; Peng, Zhigang

2016-06-01

Fault zone head waves (FZHWs) are observed along major strike-slip faults and can provide high-resolution imaging of fault interface properties at seismogenic depth. In this paper, we present a new method to automatically detect FZHWs and pick direct P waves secondary arrivals (DWSAs). The algorithm identifies FZHWs by computing the amplitude ratios between the potential FZHWs and DSWAs. The polarities, polarizations and characteristic periods of FZHWs and DSWAs are then used to refine the picks or evaluate the pick quality. We apply the method to the Parkfield section of the San Andreas Fault where FZHWs have been identified before by manual picks. We compare results from automatically and manually picked arrivals and find general agreement between them. The obtained velocity contrast at Parkfield is generally 5-10 per cent near Middle Mountain while it decreases below 5 per cent near Gold Hill. We also find many FZHWs recorded by the stations within 1 km of the background seismicity (i.e. the Southwest Fracture Zone) that have not been reported before. These FZHWs could be generated within a relatively wide low velocity zone sandwiched between the fast Salinian block on the southwest side and the slow Franciscan Mélange on the northeast side. Station FROB on the southwest (fast) side also recorded a small portion of weak precursory signals before sharp P waves. However, the polarities of weak signals are consistent with the right-lateral strike-slip mechanisms, suggesting that they are unlikely genuine FZHW signals.

75 FR 39166 - Safety Zone; San Francisco Giants Baseball Game Promotion, San Francisco, CA

Science.gov (United States)

2010-07-08

... San Francisco, CA. The fireworks display is meant for entertainment purposes. This safety zone is... National Technology Transfer and Advancement Act (NTTAA) (15 U.S.C. 272 note) directs agencies to use...), of the Instruction. This rule involves establishing, disestablishing, or changing Regulated...

SANS-1 Experimental reports of 2000

International Nuclear Information System (INIS)

Willumeit, R.; Haramus, V.

2001-01-01

The instrument SANS-1 at the Geesthacht neutron facility GeNF was used for scattering experiments in 2000 at 196 of 200 days of reactor and cold source operation. The utilisation was shared between the in-house R and D program and user groups from different universities and research centers. These measurements were performed and analysed either by guest scientists or GKSS staff. The focus of the work in 2000 at the experiment SANS-1 was the structural investigation of hydrogen containing substances such as biological macromolecules (ribosomes, protein-RNA-complexes, protein solutions, glycolipids and membranes), molecules which are important in the fields of environmental research (refractoric organic substances) and technical chemistry (surfactants, micelles). (orig.) [de

SANS studies of solutions and molecular composites prepared from cellulose tricarbanilate

CERN Document Server

Alava, C; Cameron, J D; Cowie, J M G; Vaqueiro, P; Möller, A; Triolo, A

2002-01-01

We report on SANS measurements carried out on the instrument SANS1 (V4) at the BENSC facility on solutions and composites of cellulose tricarbanilate (CTC). This cellulose derivative exhibits lyotropic behaviour in methylacrylate (MA). The SANS data indicate that in the isotropic liquid state (up to 25% wt CTC in MA) the CTC chains behave like rods of mass per unit length (M/L). In the liquid crystalline (LC) phase (at and above 35% wt CTC in MA), the Q dependence varies from Q sup - sup 1 to Q sup - sup 4 , probably as a result of self-assembling of the CTC chains. The general aim of our work is to prepare molecular composites, i.e. miscible blends of rigid-rod and flexible-coil polymers, from CTC solutions in polymerizable media. To establish the degree of homogeneity of the composites, we performed SANS measurements on UV-cured CTC/MA solutions. Here, we compare the SANS data of CTC/monomer solutions with those of the corresponding composites. (orig.)

78 FR 35593 - Special Local Regulation; Christmas Boat Parade, San Juan Harbor; San Juan, PR

Science.gov (United States)

2013-06-13

... individually or cumulatively have a significant effect on the human environment. This proposed rule involves.... Pearson, Captain, U.S. Coast Guard, Captain of the Port San Juan. [FR Doc. 2013-13994 Filed 6-12-13; 8:45...

Fault zone structure and kinematics from lidar, radar, and imagery: revealing new details along the creeping San Andreas Fault

Science.gov (United States)

DeLong, S.; Donnellan, A.; Pickering, A.

2017-12-01

Aseismic fault creep, coseismic fault displacement, distributed deformation, and the relative contribution of each have important bearing on infrastructure resilience, risk reduction, and the study of earthquake physics. Furthermore, the impact of interseismic fault creep in rupture propagation scenarios, and its impact and consequently on fault segmentation and maximum earthquake magnitudes, is poorly resolved in current rupture forecast models. The creeping section of the San Andreas Fault (SAF) in Central California is an outstanding area for establishing methodology for future scientific response to damaging earthquakes and for characterizing the fine details of crustal deformation. Here, we describe how data from airborne and terrestrial laser scanning, airborne interferometric radar (UAVSAR), and optical data from satellites and UAVs can be used to characterize rates and map patterns of deformation within fault zones of varying complexity and geomorphic expression. We are evaluating laser point cloud processing, photogrammetric structure from motion, radar interferometry, sub-pixel correlation, and other techniques to characterize the relative ability of each to measure crustal deformation in two and three dimensions through time. We are collecting new and synthesizing existing data from the zone of highest interseismic creep rates along the SAF where a transition from a single main fault trace to a 1-km wide extensional stepover occurs. In the stepover region, creep measurements from alignment arrays 100 meters long across the main fault trace reveal lower rates than those in adjacent, geomorphically simpler parts of the fault. This indicates that deformation is distributed across the en echelon subsidiary faults, by creep and/or stick-slip behavior. Our objectives are to better understand how deformation is partitioned across a fault damage zone, how it is accommodated in the shallow subsurface, and to better characterize the relative amounts of fault creep

Stratigraphic record of Pliocene-Pleistocene basin evolution and deformation within the Southern San Andreas Fault Zone, Mecca Hills, California

Science.gov (United States)

McNabb, James C.; Dorsey, Rebecca J.; Housen, Bernard A.; Dimitroff, Cassidy W.; Messé, Graham T.

2017-11-01

A thick section of Pliocene-Pleistocene nonmarine sedimentary rocks exposed in the Mecca Hills, California, provides a record of fault-zone evolution along the Coachella Valley segment of the San Andreas fault (SAF). Geologic mapping, measured sections, detailed sedimentology, and paleomagnetic data document a 3-5 Myr history of deformation and sedimentation in this area. SW-side down offset on the Painted Canyon fault (PCF) starting 3.7 Ma resulted in deposition of the Mecca Conglomerate southwest of the fault. The lower member of the Palm Spring Formation accumulated across the PCF from 3.0 to 2.6 Ma during regional subsidence. SW-side up slip on the PCF and related transpressive deformation from 2.6 to 2.3 Ma created a time-transgressive angular unconformity between the lower and upper members of the Palm Spring Formation. The upper member accumulated in discrete fault-bounded depocenters until initiation of modern deformation, uplift, and basin inversion starting at 0.7 Ma. Some spatially restricted deposits can be attributed to the evolution of fault-zone geometric complexities. However, the deformation events at ca. 2.6 Ma and 0.7 Ma are recorded regionally along 80 km of the SAF through Coachella Valley, covering an area much larger than mapped fault-zone irregularities, and thus require regional explanations. We therefore conclude that late Cenozoic deformation and sedimentation along the SAF in Coachella Valley has been controlled by a combination of regional tectonic drivers and local deformation due to dextral slip through fault-zone complexities. We further propose a kinematic link between the 2.6-2.3 Ma angular unconformity and a previously documented but poorly dated reorganization of plate-boundary faults in the northern Gulf of California at 3.3-2.0 Ma. This analysis highlights the potential for high-precision chronologies in deformed terrestrial deposits to provide improved understanding of local- to regional-scale structural controls on basin

76 FR 6517 - San Luis & Rio Grande Railroad-Petition for a Declaratory Order

Science.gov (United States)

2011-02-04

... DEPARTMENT OF TRANSPORTATION Surface Transportation Board [Docket No. FD 35380] San Luis & Rio... petition filed by San Luis & Rio Grande Railroad (SLRG), the Board instituted a declaratory order... proposed operation of a truck-to-rail transload facility in Antonito, Colorado. See San Luis & Rio Grande R...

Dal "San Marco" al "Vega". (English Title: From "San Marco" to Vega)

Science.gov (United States)

Savi, E.

2017-10-01

Apart from the two superpowers, among the other countries Italy has had an important role in astronautics. The roots of Italian astronautics' history runs deep in the hottest years of the Cold War, and it had its first remarkable achievement in the San Marco project..after years of advanced technologies testing, they achieved European cooperation and built VEGA, the current Arianespace light launcher.

Relocating San Miguel Volcanic Seismic Events for Receiver Functions and Tomographic Models

Science.gov (United States)

Patlan, E.; Velasco, A. A.; Konter, J.

2009-12-01

The San Miguel volcano lies near the city of San Miguel, El Salvador (13.43N and -88.26W). San Miguel volcano, an active stratovolcano, presents a significant natural hazard for the city of San Miguel. Furthermore, the internal state and activity of volcanoes remains an important component to understanding volcanic hazard. The main technology for addressing volcanic hazards and processes is through the analysis of data collected from the deployment of seismic sensors that record ground motion. Six UTEP seismic stations were deployed around San Miguel volcano from 2007-2008 to define the magma chamber and assess the seismic and volcanic hazard. We utilize these data to develop images of the earth structure beneath the volcano, studying the volcanic processes by identifying different sources, and investigating the role of earthquakes and faults in controlling the volcanic processes. We will calculate receiver functions to determine the thickness of San Miguel volcano internal structure, within the Caribbean plate. Crustal thicknesses will be modeled using calculated receiver functions from both theoretical and hand-picked P-wave arrivals. We will use this information derived from receiver functions, along with P-wave delay times, to map the location of the magma chamber.

El círculo meridiano automático de San Fernando - San Juan. Sus primeros pasos en el hemisferio sur

Science.gov (United States)

Mallamaci, C. C.; Muiños, J. L.; Gallego, M.; Pérez, J. A.; Marmolejo, L.; Navarro, J. L.; Sedeño, J.; Vallejos, M.; Belizón, F.

Se informa sobre el estado actual del Círculo Meridiano Automático de San Fernando-San Juan. El instrumento (Grubb-Parson, de 178mm de abertura y 2665 mm de distancia focal) es gemelo del que se encuentra en las Islas Canarias, y fue instalado durante los meses de julio y agosto de 1996 en la estación astronómica ``Dr. C.U.Cesco" (El Leoncito, Barreal), a unos 200 km de distancia de la ciudad de San Juan, merced a un Convenio de Cooperación Científica, firmado en 1994 entre el ROA (España) y el OAFA (Argentina). En la actualidad se está llevando a cabo un programa de prueba cuyos resultados preliminares muestran que el telescopio está en buenas condiciones para observar estrellas de hasta magnitud aproximada 14.5, con buenos errores de observación (<0.12" en ascensión recta y declinación).

Characterization of alumina using small angle neutron scattering (SANS)

International Nuclear Information System (INIS)

Megat Harun Al Rashidn Megat Ahmad; Abdul Aziz Mohamed; Azmi Ibrahim; Che Seman Mahmood; Edy Giri Rachman Putra; Muhammad Rawi Muhammad Zin; Razali Kassim; Rafhayudi Jamro

2007-01-01

Alumina powder was synthesized from an aluminium precursor and studied using small angle neutron scattering (SANS) technique and complemented with transmission electron microscope (TEM). XRD measurement confirmed that the alumina produced was high purity and highly crystalline αphase. SANS examination indicates the formation of mass fractals microstructures with fractal dimension of about 2.8 on the alumina powder. (Author)

Species - San Diego Co. [ds121

Data.gov (United States)

California Natural Resource Agency — This is the Biological Observation Database point layer representing baseline observations of sensitive species (as defined by the MSCP) throughout San Diego County....

Lipid based drug delivery systems: Kinetics by SANS

Science.gov (United States)

Uhríková, D.; Teixeira, J.; Hubčík, L.; Búcsi, A.; Kondela, T.; Murugova, T.; Ivankov, O. I.

2017-05-01

N,N-dimethyldodecylamine-N-oxide (C12NO) is a surfactant that may exist either in a neutral or protonated form depending on the pH of aqueous solutions. Using small angle X-ray diffraction (SAXD) we demonstrate structural responsivity of C12NO/dioleoylphospha-tidylethanolamine (DOPE)/DNA complexes designed as pH sensitive gene delivery vectors. Small angle neutron scattering (SANS) was employed to follow kinetics of C12NO protonization and DNA binding into C12NO/DOPE/DNA complexes in solution of 150 mM NaCl at acidic condition. SANS data analyzed using paracrystal lamellar model show the formation of complexes with stacking up to ∼32 bilayers, spacing ∼ 62 Å, and lipid bilayer thickness ∼37 Å in 3 minutes after changing pH from 7 to 4. Subsequent structural reorganization of the complexes was observed along 90 minutes of SANS mesurements.

Lipid based drug delivery systems: Kinetics by SANS

International Nuclear Information System (INIS)

Uhríková, D; Hubčík, L; Búcsi, A; Kondela, T; Teixeira, J; Murugova, T; Ivankov, O I

2017-01-01

N,N-dimethyldodecylamine-N-oxide (C 12 NO) is a surfactant that may exist either in a neutral or protonated form depending on the pH of aqueous solutions. Using small angle X-ray diffraction (SAXD) we demonstrate structural responsivity of C 12 NO/dioleoylphospha-tidylethanolamine (DOPE)/DNA complexes designed as pH sensitive gene delivery vectors. Small angle neutron scattering (SANS) was employed to follow kinetics of C 12 NO protonization and DNA binding into C 12 NO/DOPE/DNA complexes in solution of 150 mM NaCl at acidic condition. SANS data analyzed using paracrystal lamellar model show the formation of complexes with stacking up to ∼32 bilayers, spacing ∼ 62 Å, and lipid bilayer thickness ∼37 Å in 3 minutes after changing pH from 7 to 4. Subsequent structural reorganization of the complexes was observed along 90 minutes of SANS mesurements. (paper)

Geologic Map of the San Luis Quadrangle, Costilla County, Colorado

Science.gov (United States)

Machette, Michael N.; Thompson, Ren A.; Drenth, Benjamin J.

2008-01-01

The map area includes San Luis and the primarily rural surrounding area. San Luis, the county seat of Costilla County, is the oldest surviving settlement in Colorado (1851). West of the town are San Pedro and San Luis mesas (basalt-covered tablelands), which are horsts with the San Luis fault zone to the east and the southern Sangre de Cristo fault zone to the west. The map also includes the Sanchez graben (part of the larger Culebra graben), a deep structural basin that lies between the San Luis fault zone (on the west) and the central Sangre de Cristo fault zone (on the east). The oldest rocks exposed in the map area are the Pliocene to upper Oligocene basin-fill sediments of the Santa Fe Group, and Pliocene Servilleta Basalt, a regional series of 3.7?4.8 Ma old flood basalts. Landslide deposits and colluvium that rest on sediments of the Santa Fe Group cover the steep margins of the mesas. Rare exposures of the sediment are comprised of siltstones, sandstones, and minor fluvial conglomerates. Most of the low ground surrounding the mesas and in the graben is covered by surficial deposits of Quaternary age. The alluvial deposits are subdivided into three Pleistocene-age units and three Holocene-age units. The oldest Pleistocene gravel (unit Qao) forms extensive coalesced alluvial fan and piedmont surfaces, the largest of which is known as the Costilla Plain. This surface extends west from San Pedro Mesa to the Rio Grande. The primary geologic hazards in the map area are from earthquakes, landslides, and localized flooding. There are three major fault zones in the area (as discussed above), and they all show evidence for late Pleistocene to possible Holocene movement. The landslides may have seismogenic origins; that is, they may be stimulated by strong ground shaking during large earthquakes. Machette and Thompson based this geologic map entirely on new mapping, whereas Drenth supplied geophysical data and interpretations.

33 CFR 165.758 - Security Zone; San Juan, Puerto Rico.

Science.gov (United States)

2010-07-01

... Security Zone; San Juan, Puerto Rico. (a) Location. Moving and fixed security zones are established 50... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone; San Juan, Puerto Rico. 165.758 Section 165.758 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND...

Resistance Management for San Jose Scale (Hemiptera: Diaspididae).

Science.gov (United States)

Buzzetti, K; Chorbadjian, R A; Nauen, R

2015-12-01

The San Jose scale Diaspidiotus perniciosus Comstock is one of the most important pests of deciduous fruit trees. The major cause of recent outbreaks in apple orchards is thought to be the development of insecticide resistance, specifically organophosphates. The first report was given in North America, and now, in Chile. In the present study, San Jose scale populations collected from two central regions of Chile were checked for their susceptibility to different mode of action insecticides in order to establish alternatives to manage this pest. No evidence of cross resistance between organophosphates insecticides and acetamiprid, buprofezin, pyriproxyfen, spirotetramat, sulfoxaflor, or thiacloprid was found. Baselines of LC50-LC95 for different life stages of San Jose scale are given, as reference to future studies of resistance monitoring. The systemic activity of acetamiprid, spirotetramat, and thiacloprid was higher than the contact residue effect of these compounds. For sulfoxaflor, both values were similar. Program treatments including one or more of these compounds are compared in efficacy and impact on resistance ratio values. In order to preserve new insecticides as an important tool to control San Jose scale, resistance management programs should be implemented, considering insecticide mode of action classes alternated or mixed. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A new record for American Bullfrog (Lithobates catesbeianus in San Juan, Argentina Nuevo registro de rana toro americana (Lithobates catesbeianus en San Juan, Argentina

Directory of Open Access Journals (Sweden)

Eduardo Sanabria

2011-03-01

Full Text Available We report a new record of Lithobates catesbeianus (American bullfrog from Argentina. L. catesbeianus was first introduced to San Juan Province 11 years ago in Calingasta Department, where the habitat is pre-cordilleran. The new record is for Zonda Department, San Juan Province, in the Monte desert region. Here, L. catesbeianus uses artificial ponds for reproduction and tadpole development. These ponds receive water from an irrigation system that connects the whole agriculture land in the region. The tadpoles use the irrigation canals to move among ponds. We suggest that legislation should be established to prevent future invasions and to achieve sustainable management of the wild American bullfrog populations in San Juan. Prevention of future invasion and management of established populations of this species requires the cooperation of numerous stake holders.Se presenta un nuevo registro de Lithobates catesbeianus (rana toro americana en Argentina. L. catesbeianus fue introducida por primera vez a la provincia de San Juan hace 11 años en el Departamento Calingasta, donde el hábitat es pre-cordillerano. El nuevo registro es para el Departamento Zonda en la provincia de San Juan, en el desierto del Monte. En este sitio, L. catesbeianus usa estanques artificiales para la reproducción y desarrollo del renacuajo. Los estanques reciben agua de un sistema de riego que conecta todas las tierras de la agricultura en la región. Los renacuajos utilizan los canales de riego para moverse entre los estanques. Sugerimos que se establezcan leyes para prevenir invasiones futuras y para lograr un manejo integrado de las poblaciones silvestres de rana toro que se encuentran en San Juan. La prevención de futuras invasiones y el manejo de las poblaciones establecidas de esta especie requieren la cooperación de numerosas entidades tanto gubernamentales como privadas.

New fault picture points toward San Francisco Bay area earthquakes

Science.gov (United States)

Kerr, R. A.

1989-01-01

Recent earthquakes and a new way of looking at faults suggest that damaging earthquakes are closing in on the San Francisco area. Earthquakes Awareness Week 1989 in northern California started off with a bang on Monday, 3 April, when a magnitude 4.8 earthquake struck 15 kilometers northeast of San Jose. The relatively small shock-its primary damage was the shattering of an air-control tower window-got the immediate attention of three U.S Geological Survey seismologists in Menlo Park near San Francisco. David Oppenheimer, William Bakun, and Allan Lindh had forecast a nearby earthquake in a just completed report, and this, they thought, might be it. 

The San values of conflict prevention and avoidance in Platfontein

Directory of Open Access Journals (Sweden)

Nina Mollema

2017-09-01

Full Text Available The aim of this article is to identify measures that can prevent violent conflict through the maintenance of traditional cultural values that guide conflict avoidance. Moreover, the article focuses on the concepts of conflict prevention and conflict avoidance as applied by the San community of Platfontein. The causes of the inter-communal tensions between the San community members are also examined. A selected conflict situation, that of superstition and witchcraft, is assessed as factors increasing interpersonal conflict in the Platfontein community. This investigation is made to determine if the San preventive measures have an impact in the community, so as to prevent ongoing conflicts from escalating further.

El castillo de San Romualdo (San Fernando, Cádiz. Aproximación estratigráfica y evolución constructiva

Directory of Open Access Journals (Sweden)

Utrera Burgal, Raquel M.

2009-12-01

Full Text Available This article shows the results of the archaeological research carried out in the castle of San Romualdo, the most emblematic building of the city of San Fernando and a defensive fortress tied to the control access of Cádiz. The standing building recording has enabled to know the building evolution from its origins until the present. Studies have hitherto confirmed the chronological conclusions already proposed in 2003. That is, the current castle is a medieval Christian building erected in the second half of the 13th century thanks to Mudejar workers and materials reused from a previous building.Presentamos en este artículo los resultados de nuestra investigación arqueológica en el castillo de San Romualdo, el edificio más emblemático de la ciudad de San Fernando y fortaleza defensiva ligada al control del acceso a Cádiz. El análisis estratigráfico de alzados ha permitido conocer la evolución constructiva del edificio, desde sus orígenes hasta la actualidad. Hasta ahora los estudios confirman las conclusiones en cuanto a su datación presentadas en el año 2003, es decir, el castillo, tal y como hoy lo conocemos, es una construcción medieval cristiana, realizada durante la segunda mitad del siglo XIII, con mano de obra mudéjar y con materiales reutilizados de una edificación anterior.

The San Diego Panasonic Partnership: A Case Study in Restructuring.

Science.gov (United States)

Holzman, Michael; Tewel, Kenneth J.

1992-01-01

The Panasonic Foundation provides resources for restructuring school districts. The article examines its partnership with the San Diego City School District, highlighting four schools that demonstrate promising practices and guiding principles. It describes recent partnership work on systemic issues, noting the next steps to be taken in San Diego.…

Characterizing the Organic Matter in Surface Sediments from the San Juan Bay Estuary,

Science.gov (United States)

The San Juan Bay Estuary (SJBE) is located on the north coast of Puerto Rico and includes the San Juan Bay, San José Lagoon, La Torrecilla Lagoon and Piñones Lagoon, as well as the Martín Peña and the Suárez Canals. The SJBE watershed has the highest...

Cuartel San Carlos. Yacimiento veterano

Directory of Open Access Journals (Sweden)

Mariana Flores

2007-01-01

Full Text Available El Cuartel San Carlos es un monumento histórico nacional (1986 de finales del siglo XVIII (1785-1790, caracterizado por sufrir diversas adversidades en su construcción y soportar los terremotos de 1812 y 1900. En el año 2006, el organismo encargado de su custodia, el Instituto de Patrimonio Cultural del Ministerio de Cultura, ejecutó tres etapas de exploración arqueológica, que abarcaron las áreas Traspatio, Patio Central y las Naves Este y Oeste de la edificación. Este trabajo reseña el análisis de la documentación arqueológica obtenida en el sitio, a partir de la realización de dicho proyecto, denominado EACUSAC (Estudio Arqueológico del Cuartel San Carlos, que representa además, la tercera campaña realizada en el sitio. La importancia de este yacimiento histórico, radica en su participación en los acontecimientos que propiciaron conflictos de poder durante el surgimiento de la República y en los sucesos políticos del siglo XX. De igual manera, se encontró en el sitio una amplia muestra de materiales arqueológicos que reseñan un estilo de vida cotidiana militar, así como las dinámicas sociales internas ocurridas en el San Carlos, como lugar estratégico para la defensa de los diferentes regímenes que atravesó el país, desde la época del imperialismo español hasta nuestros días.

San Francisco urban partnership agreement, national evaluation : exogenous factors test plan.

Science.gov (United States)

2011-06-01

This report presents the test plan for collecting and analyzing exogenous factors data for the San Francisco Urban : Partnership Agreement (UPA) under the United States Department of Transportation (U.S. DOT) UPA Program. : The San Francisco UPA proj...

Identifying Fault Connections of the Southern Pacific-North American Plate Boundary Using Triggered Slip and Crustal Velocities

Science.gov (United States)

Donnellan, A.; Grant Ludwig, L.; Rundle, J. B.; Parker, J. W.; Granat, R.; Heflin, M. B.; Pierce, M. E.; Wang, J.; Gunson, M.; Lyzenga, G. A.

2017-12-01

The 2010 M7.2 El Mayor - Cucapah earthquake caused extensive triggering of slip on faults proximal to the Salton Trough in southern California. Triggered slip and postseismic motions that have continued for over five years following the earthquake highlight connections between the El Mayor - Cucapah rupture and the network of faults that branch out along the southern Pacific - North American Plate Boundary. Coseismic triggering follows a network of conjugate faults from the northern end of the rupture to the Coachella segment of the southernmost San Andreas fault. Larger aftershocks and postseismic motions favor connections to the San Jacinto and Elsinore faults further west. The 2012 Brawley Swarm can be considered part of the branching on the Imperial Valley or east side of the plate boundary. Cluster analysis of long-term GPS velocities using Lloyds Algorithm, identifies bifurcation of the Pacific - North American plate boundary; The San Jacinto fault joins with the southern San Andreas fault, and the Salton Trough and Coachella segment of the San Andreas fault join with the Eastern California Shear Zone. The clustering analysis does not identify throughgoing deformation connecting the Coachella segment of the San Andreas fault with the rest of the San Andreas fault system through the San Gorgonio Pass. This observation is consistent with triggered slip from both the 1992 Landers and 2010 El Mayor - Cucapah earthquakes that follows the plate boundary bifurcation and with paleoseismic evidence of smaller earthquakes in the San Gorgonio Pass.

Maps of Quaternary Deposits and Liquefaction Susceptibility in the Central San Francisco Bay Region, California

Science.gov (United States)

Witter, Robert C.; Knudsen, Keith L.; Sowers, Janet M.; Wentworth, Carl M.; Koehler, Richard D.; Randolph, Carolyn E.; Brooks, Suzanna K.; Gans, Kathleen D.

2006-01-01

This report presents a map and database of Quaternary deposits and liquefaction susceptibility for the urban core of the San Francisco Bay region. It supercedes the equivalent area of U.S. Geological Survey Open-File Report 00-444 (Knudsen and others, 2000), which covers the larger 9-county San Francisco Bay region. The report consists of (1) a spatial database, (2) two small-scale colored maps (Quaternary deposits and liquefaction susceptibility), (3) a text describing the Quaternary map and liquefaction interpretation (part 3), and (4) a text introducing the report and describing the database (part 1). All parts of the report are digital; part 1 describes the database and digital files and how to obtain them by downloading across the internet. The nine counties surrounding San Francisco Bay straddle the San Andreas fault system, which exposes the region to serious earthquake hazard (Working Group on California Earthquake Probabilities, 1999). Much of the land adjacent to the Bay and the major rivers and streams is underlain by unconsolidated deposits that are particularly vulnerable to earthquake shaking and liquefaction of water-saturated granular sediment. This new map provides a consistent detailed treatment of the central part of the 9-county region in which much of the mapping of Open-File Report 00-444 was either at smaller (less detailed) scale or represented only preliminary revision of earlier work. Like Open-File Report 00-444, the current mapping uses geomorphic expression, pedogenic soils, inferred depositional environments, and geologic age to define and distinguish the map units. Further scrutiny of the factors controlling liquefaction susceptibility has led to some changes relative to Open-File Report 00-444: particularly the reclassification of San Francisco Bay mud (Qhbm) to have only MODERATE susceptibility and the rating of artificial fills according to the Quaternary map units inferred to underlie them (other than dams - adf). The two colored

San Francisco Bay Water Quality Improvement Fund Map Service, San Francisco CA, 2012, US EPA Region 9

Data.gov (United States)

U.S. Environmental Protection Agency — The San Francisco Bay Water Quality Improvement Fund is a competitive grant program that is helping implement TMDLs to improve water quality, protect wetlands, and...

San Francisco Bay Water Quality Improvement Fund Project Locations, San Francisco CA, 2017, US EPA Region 9

Data.gov (United States)

U.S. Environmental Protection Agency — The San Francisco Bay Water Quality Improvement Fund is a competitive grant program that is helping implement TMDLs to improve water quality, protect wetlands, and...

An overview of San Francisco Bay PORTS

Science.gov (United States)

Cheng, Ralph T.; McKinnie, David; English, Chad; Smith, Richard E.

1998-01-01

The Physical Oceanographic Real-Time System (PORTS) provides observations of tides, tidal currents, and meteorological conditions in real-time. The San Francisco Bay PORTS (SFPORTS) is a decision support system to facilitate safe and efficient maritime commerce. In addition to real-time observations, SFPORTS includes a nowcast numerical model forming a San Francisco Bay marine nowcast system. SFPORTS data and nowcast numerical model results are made available to users through the World Wide Web (WWW). A brief overview of SFPORTS is presented, from the data flow originated at instrument sensors to final results delivered to end users on the WWW. A user-friendly interface for SFPORTS has been designed and implemented. Appropriate field data analysis, nowcast procedures, design and generation of graphics for WWW display of field data and nowcast results are presented and discussed. Furthermore, SFPORTS is designed to support hazardous materials spill prevention and response, and to serve as resources to scientists studying the health of San Francisco Bay ecosystem. The success (or failure) of the SFPORTS to serve the intended user community is determined by the effectiveness of the user interface.

Evaluating the quality of life of people with profound and multiple disabilities: Use of the San Martín Scale at the Obra San Martín Foundation

Directory of Open Access Journals (Sweden)

Irene Hierro Zorrilla

2015-06-01

Full Text Available The San Martín Scale is an instrument used to measure the quality of life of people with significant disabilities with adequate levels reliability and validity. In 2012, the San Martín Scale was administered to 85 adults with intellectual disabilities who were provided supports at Obra San Martin Foundation (Santander. In this article, we describe the results obtained at the mesosystem level, an example at the microsystem level, and future areas of work identified from the results.

AMS San Diego Testbed - Calibration Data

Data.gov (United States)

Department of Transportation — The data in this repository were collected from the San Diego, California testbed, namely, I-15 from the interchange with SR-78 in the north to the interchange with...

Hydrologic data from wells at or in the vicinity of the San Juan coal mine, San Juan County, New Mexico

Science.gov (United States)

Stewart, Anne M.; Thomas, Nicole

2015-01-01

In 2010, in cooperation with the Mining and Minerals Division (MMD) of the State of New Mexico Energy, Minerals and Natural Resources Department, the U.S. Geological Survey (USGS) initiated a 4-year assessment of hydrologic conditions at the San Juan coal mine (SJCM), located about 14 miles west-northwest of the city of Farmington, San Juan County, New Mexico. The mine produces coal for power generation at the adjacent San Juan Generating Station (SJGS) and stores coal-combustion byproducts from the SJGS in mined-out surface-mining pits. The purpose of the hydrologic assessment is to identify groundwater flow paths away from SJCM coal-combustion-byproduct storage sites that might allow metals that may be leached from coal-combustion byproducts to eventually reach wells or streams after regional dewatering ceases and groundwater recovers to predevelopment levels. The hydrologic assessment, undertaken between 2010 and 2013, included compilation of existing data. The purpose of this report is to present data that were acquired and compiled by the USGS for the SJCM hydrologic assessment.

Chemical controls on fault behavior: weakening of serpentinite sheared against quartz-bearing rocks and its significance for fault creep in the San Andreas system

Science.gov (United States)

Moore, Diane E.; Lockner, David A.

2013-01-01

The serpentinized ultramafic rocks found in many plate-tectonic settings commonly are juxtaposed against crustal rocks along faults, and the chemical contrast between the rock types potentially could influence the mechanical behavior of such faults. To investigate this possibility, we conducted triaxial experiments under hydrothermal conditions (200-350°C), shearing serpentinite gouge between forcing blocks of granite or quartzite. In an ultramafic chemical environment, the coefficient of friction, µ, of lizardite and antigorite serpentinite is 0.5-0.6, and µ increases with increasing temperature over the tested range. However, when either lizardite or antigorite serpentinite is sheared against granite or quartzite, strength is reduced to µ ~ 0.3, with the greatest strength reductions at the highest temperatures (temperature weakening) and slowest shearing rates (velocity strengthening). The weakening is attributed to a solution-transfer process that is promoted by the enhanced solubility of serpentine in pore fluids whose chemistry has been modified by interaction with the quartzose wall rocks. The operation of this process will promote aseismic slip (creep) along serpentinite-bearing crustal faults at otherwise seismogenic depths. During short-term experiments serpentine minerals reprecipitate in low-stress areas, whereas in longer experiments new Mg-rich phyllosilicates crystallize in response to metasomatic exchanges across the serpentinite-crustal rock contact. Long-term shear of serpentinite against crustal rocks will cause the metasomatic mineral assemblages, which may include extremely weak minerals such as saponite or talc, to play an increasingly important role in the mechanical behavior of the fault. Our results may explain the distribution of creep on faults in the San Andreas system.

San Telmo, backpackers y otras globalizaciones

Directory of Open Access Journals (Sweden)

Fernando Firmo

2015-12-01

Full Text Available Este artículo pretende contribuir al debate sobre otras formas de globalización  presentando una etnografía realizada en el barrio de San Telmo sobre mochileros que combinan en sus experiencias viaje y trabajo. Su objetivo es viajar al mismo tiempo que sacan provecho de esto para conseguir el capital necesario que les permita continuar en movimiento alrededor del globo. En este texto quiero hablar sobre estos auténticos actores de la globalización popular que ponen el foco en procesos y agentes alternativos no hegemónicos y que en este caso desarrollan su actividad en el contexto de la experiencia mochilera en San Telmo, siendo mi intención enriquecer las reflexiones sobre la globalización desde abajo.

Small angle neutron scattering (SANS) under non-equilibrium conditions

International Nuclear Information System (INIS)

Oberthur, R.C.

1984-01-01

The use of small angle neutron scattering (SANS) for the study of systems under non-equilibrium conditions is illustrated by three types of experiments in the field of polymer research: - the relaxation of a system from an initial non-equilibrium state towards equilibrium, - the cyclic or repetitive installation of a series of non-equilibrium states in a system, - the steady non-equilibrium state maintained by a constant dissipation of energy within the system. Characteristic times obtained in these experiments with SANS are compared with the times obtained from quasi-elastic neutron and light scattering, which yield information about the equilibrium dynamics of the system. The limits of SANS applied to non-equilibrium systems for the measurement of relaxation times at different length scales are shown and compared to the limits of quasielastic neutron and light scattering

San Jacinto Tries Management by Objectives

Science.gov (United States)

Deegan, William

1974-01-01

San Jacinto, California, has adopted a measurable institutional objectives approach to management by objectives. Results reflect, not only improved cost effectiveness of community college education, but also more effective educational programs for students. (Author/WM)

Crustal strain near the Big Bend of the San Andreas Fault: Analysis of the Los Padres-Tehachapi Trilateration Networks, California

Science.gov (United States)

Eberhart-Phillips, Donna; Lisowski, Michael; Zoback, Mark D.

1990-02-01

In the region of the Los Padres-Tehachapi geodetic network, the San Andreas fault (SAF) changes its orientation by over 30° from N40°W, close to that predicted by plate motion for a transform boundary, to N73°W. The strain orientation near the SAF is consistent with right-lateral shear along the fault, with maximum shear rate of 0.38±0.01 μrad/yr at N63°W. In contrast, away from the SAF the strain orientations on both sides of the fault are consistent with the plate motion direction, with maximum shear rate of 0.19±0.01 μrad/yr at N44°W. The strain rate does not drop off rapidly away from the fault, and thus the area is fit by either a broad shear zone below the SAF or a single fault with a relatively deep locking depth. The fit to the line length data is poor for locking depth d less than 25 km. For d of 25 km a buried slip rate of 30 ± 6 mm/yr is estimated. We also estimated buried slip for models that included the Garlock and Big Pine faults, in addition to the SAF. Slip rates on other faults are poorly constrained by the Los Padres-Tehachapi network. The best fitting Garlock fault model had computed left-lateral slip rate of 11±2 mm/yr below 10 km. Buried left-lateral slip of 15±6 mm/yr on the Big Pine fault, within the Western Transverse Ranges, provides significant reduction in line length residuals; however, deformation there may be more complicated than a single vertical fault. A subhorizontal detachment on the southern side of the SAF cannot be well constrained by these data. We investigated the location of the SAF and found that a vertical fault below the surface trace fits the data much better than either a dipping fault or a fault zone located south of the surface trace.

Solar-energy-system performance evaluation. San Anselmo School, San Jose, California, April 1981-March 1982

Energy Technology Data Exchange (ETDEWEB)

Pakkala, P.A.

1982-01-01

The San Anselmo School is a one-story brick elementary school building in San Jose, California. The active solar energy system is designed to supply 70% of the space heating and 72% of the cooling load. It is equipped with 3740 square feet of evacuated tube collectors, a 2175-gallon tank for heat storage, a solar-supplied absorption chiller, and four auxiliary gas-fired absorption chillers/heaters. The measured solar fraction of 19% is far below the expected values and is attributed to severe system control and HVAC problems. Other performance data given for the year include the solar savings ratio, conventional fuel savings, system performance factor, and solar system coefficient of performance. Also tabulated are monthly performance data for the overall solar energy system, collector subsystem, space heating and cooling subsystems. Typical hourly operation data for a day are tabulated, including hourly isolation, collector array temperatures (inlet and outlet), and storage fluid temperatures. The solar energy use and percentage of losses are also graphed. (LEW)

Solar-energy system performance evaluation. San Anselmo School, San Jose, California, July 1980-March 1981

Energy Technology Data Exchange (ETDEWEB)

Pakkala, P.A.

1981-01-01

The San Anselmo School is a one-story, brick elementary school building located in San Jose, California. The active solar energy system is designed to supply 70% of the heating load and 72% of the cooling load. It is equipped with 3.740 square feet of evacuated tube collectors, 2175-gallon tank for storage, four auxiliary gas-fired absorption chiller/heaters, and a solar-supplied absorption chiller. The measured heating and cooling solar fractions were 9% and 19%, respectively, for an overall solar fraction of 16%, the lowered performance being attributed to severe system control problems. Performance data include the solar savings ratio, conventional fuel savings, system performance factor, and solar system coefficient of performance. Performance data are presented for the overall system and for each subsystem. System operation and solar energy utilization data are included. Also included are a description of the system, performance evaluation techniques, sensor technology, and typical performance data for a month. Weather data are also tabulated. (LEW)

Como güelfos y gibelinos: los colegios de San Bernardo y San Antonio Abad en el Cuzco durante el siglo XVII

Directory of Open Access Journals (Sweden)

Guibovich Pérez, Pedro M

2006-04-01

Full Text Available This article deals with the conflicts that involved the San Bernardo and San Antonio schools all along the seventeenth century. The author proposes a new approach to explain the social history of colonial Cuzco. He mantains that the root of the confrontation has to do with the privileges that enjoy the jesuits in the provision of academical degrees, a basic requirement to obtain appointments in the civil and eclesiastical administration. To understand this social dinamic, he reconstructs the institutional history of both schools, and reveals the interests that defend the main actors of this secular conflict.

Los conflictos que enfrentaron a los colegios de San Bernardo y San Antonio Abad a lo largo del siglo XVII es el tema central de estudio de este ensayo. El autor propone una nueva lectura a este episodio de la historia social del Cuzco colonial. Sostiene que en la raíz de los enfrentamientos estuvo el privilegio que gozaban los jesuitas para la concesión de grados académicos, requisitos fundamentales para obtener cargos en la administración civil y eclesiástica. Para entender la dinámica social, el autor reconstruye la historia institucional de los colegios y los intereses en juego de los principales protagonistas del secular conflicto.

Rayleigh wave group velocity and shear wave velocity structure in the San Francisco Bay region from ambient noise tomography

Science.gov (United States)

Li, Peng; Thurber, Clifford

2018-06-01

We derive new Rayleigh wave group velocity models and a 3-D shear wave velocity model of the upper crust in the San Francisco Bay region using an adaptive grid ambient noise tomography algorithm and 6 months of continuous seismic data from 174 seismic stations from multiple networks. The resolution of the group velocity models is 0.1°-0.2° for short periods (˜3 s) and 0.3°-0.4° for long periods (˜10 s). The new shear wave velocity model of the upper crust reveals a number of important structures. We find distinct velocity contrasts at the Golden Gate segment of the San Andreas Fault, the West Napa Fault, central part of the Hayward Fault and southern part of the Calaveras Fault. Low shear wave velocities are mainly located in Tertiary and Quaternary basins, for instance, La Honda Basin, Livermore Valley and the western and eastern edges of Santa Clara Valley. Low shear wave velocities are also observed at the Sonoma volcanic field. Areas of high shear wave velocity include the Santa Lucia Range, the Gabilan Range and Ben Lomond Plutons, and the Diablo Range, where Franciscan Complex or Silinian rocks are exposed.

April 1906 San Francisco, USA Images

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The 1906 San Francisco earthquake was the largest event (magnitude 8.3) to occur in the conterminous United States in the 20th Century. Recent estimates indicate...

Imaging Stress Transients and Fault Zone Processes with Crosswell Continuous Active-Source Seismic Monitoring at the San Andreas Fault Observatory at Depth

Science.gov (United States)

Niu, F.; Taira, T.; Daley, T. M.; Marchesini, P.; Robertson, M.; Wood, T.

2017-12-01

Recent field and laboratory experiments identify seismic velocity changes preceding microearthquakes and rock failure (Niu et al., 2008, Nature; Scuderi et al., 2016, NatureGeo), which indicates that a continuous monitoring of seismic velocity might provide a mean of understanding of the earthquake nucleation process. Crosswell Continuous Active-Source Seismic Monitoring (CASSM) using borehole sources and sensors has proven to be an effective tool for measurements of seismic velocity and its temporal variation at seismogenic depth (Silver, et al, 2007, BSSA; Daley, et al, 2007, Geophysics). To expand current efforts on the CASSM development, in June 2017 we have begun to conduct a year-long CASSM field experiment at the San Andreas Fault Observatory at Depth (SAFOD) in which the preceding field experiment detected the two sudden velocity reductions approximately 10 and 2 hours before microearthquakes (Niu et al., 2008, Nature). We installed a piezoelectric source and a three-component accelerometer at the SAFOD pilot and main holes ( 1 km depth) respectively. A seismic pulse was fired from the piezoelectric source four times per second. Each waveform was recorded 150-ms-long data with a sampling rate of 48 kHz. During this one-year experiment, we expect to have 10-15 microearthquakes (magnitude 1-3) occurring near the SAFOD site, and the data collected from the new experiment would allow us to further explore a relation between velocity changes and the Parkfield seismicity. Additionally, the year-long data provide a unique opportunity to study long-term velocity changes that might be related to seasonal stress variations at Parkfield (Johnson et al., 2017, Science). We will report on initial results of the SAFOD CASSM experiment and operational experiences of the CASSM development.

SANS from interpenetrating polymer networks

International Nuclear Information System (INIS)

Markotsis, M.G.; Burford, R.P.; Knott, R.B.; Australian Nuclear Science and Technology Organisation, Menai, NSW; Hanley, T.L.; CRC for Polymers,; Australian Nuclear Science and Technology Organisation, Menai, NSW; Papamanuel, N.

2003-01-01

Full text: Interpenetrating polymer networks (IPNs) have been formed by combining two polymeric systems in order to gain enhanced material properties. IPNs are a combination of two or more polymers in network form with one network polymerised and/or crosslinked in the immediate presence of the other(s).1 IPNs allow better blending of two or more crosslinked networks. In this study two sets of IPNs were produced and their microstructure studied using a variety of techniques including small angle neutron scattering (SANS). The first system combined a glassy polymer (polystyrene) with an elastomeric polymer (SBS) with the glassy polymer predominating, to give a high impact plastic. The second set of IPNs contained epichlorohydrin (CO) and nitrile rubber (NBR), and was formed in order to produce novel materials with enhanced chemical and gas barrier properties. In both cases if the phase mixing is optimised the probability of controlled morphologies and synergistic behaviour is increased. The PS/SBS IPNs were prepared using sequential polymerisation. The primary SBS network was thermally crosslinked, then the polystyrene network was polymerised and crosslinked using gamma irradiation to avoid possible thermal degradation of the butadiene segment of the SBS. Tough transparent systems were produced with no apparent thermal degradation of the polybutadiene segments. The epichlorohydrin/nitrile rubber IPNs were formed by simultaneous thermal crosslinking reactions. The epichlorohydrin network was formed using lead based crosslinker, while the nitrile rubber was crosslinked by peroxide methods. The use of two different crosslinking systems was employed in order to achieve independent crosslinking thus resulting in an IPN with minimal grafting between the component networks. SANS, Transmission electron microscopy (TEM), and atomic force microscopy (AFM) were used to examine the size and shape of the phase domains and investigate any variation with crosslinking level and

The Basic Design Report of the 40M SANS Instrument

Energy Technology Data Exchange (ETDEWEB)

Han, Young Soo; Lee, Chang Hee; Hwang, Dong Gil; Kim, Hak Rho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Tae Hwan; Choi, Sung Min [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

2006-04-15

The HANARO cold neutron research facility project was launched on July 1, 2003. A state of the art SANS instrument was selected as a top-priority instrument by an instrument selection committee, which consisted of domestic users and HANARO personnel. An instrument development team and an international and domestic instrument advisory team were formulated. The guide and the instrument simulation were performed using Vitess software and the optimum basic design was completed based on the simulation results and the international advisory team reviews. The optimum design of the guide for the 40M SANS instrument was completed and the optimum basic design of the 40M the SANS instrument was also completed based on the Vitess simulation results. The Q range of the instrument will cover from 0.0008 to 1.0 A-1 and the maximum flux at a sample position can reach about 5.5x10 7 n/cm2sec. The simulation results and the basic design product will be used for the detailed design and the construction of the SANS instrument. The simulation results could be applied to the development of the other instrument.

DNA array analysis of gene expression changes by Choto-san in the ischemic rat brain

OpenAIRE

Tohda, Michihisa; Matsumoto, Kinzo; Hayashi, Hisae; Murakami, Yukihisa; Watanabe, Hiroshi

2004-01-01

The effects of Choto-san on gene expression in the dementia model rat brain were studied using a DNA microarray system. Choto-san inhibited the expression of 181 genes that has been enhanced by permanent occlusion of the bilateral common carotid arteries (2VO). Choto-san also reversed the expression inhibition of 32 genes induced by 2VO. These results may suggest that Choto-san, which has been therapeutically used as an antidementive drug, shows therapeutic effects through gene expression cha...

Transpressional deformation style and AMS fabrics adjacent to the southernmost segment of the San Andreas fault, Durmid Hill, CA

Science.gov (United States)

French, M.; Wojtal, S. F.; Housen, B.

2006-12-01

In the Salton Trough, the trace of the San Andreas Fault (SAF) ends where it intersects the NNW-trending Brawley seismic zone at Durmid Hill (DH). The topographic relief of DH is a product of faulting and folding of Pleistocene Borrego Formation strata (Babcock, 1974). Burgmann's (1991) detailed mapping and analysis of the western part of DH showed that the folds and faults accommodate transpression. Key to Burgmann's work was the recognition that the ~2m thick Bishop Ash, a prominent marker horizon, has been elongated parallel to the hinges of folds and boudinaged. We are mapping in detail the eastern portion of DH, nearer to the trace of the SAF. Folds in the eastern part of DH are tighter and thrust faulting is more prominent, consistent with greater shortening magnitude oblique to the SAF. Boudinage of the ash layer again indicates elongation parallel to fold hinges and subparallel to the SAF. The Bishop Ash locally is limbs in eastern DH, suggesting that significant continuous deformation accompanied the development of map-scale features. We measured anisotropy of magnetic susceptibility (AMS) fabrics in the Bishop Ash in order to assess continuous deformation in the Ash at DH. Because the Bishop Ash at DH is altered, consisting mainly of silica glass and clay minerals, samples from DH have significantly lower magnetic susceptibilities than Bishop Ash samples from elsewhere in the Salton Trough. With such low susceptibilities, there is significant scatter in the orientation of magnetic foliation and lineation in our samples. Still, in some Bishop samples within 1 km of the SAF, magnetic foliation is consistent with fold-related flattening. Magnetic lineation in these samples is consistently sub-parallel to fold hinges, parallel to the elongation direction inferred from boudinage. Even close to the trace of the SAF, this correlation breaks down in map-scale zones where fold hinge lines change attitude, fold shapes change, and the distribution and orientations

Public Involvement and Response Plan (Community Relations Plan), Presidio of San Francisco, San Francisco, California

Science.gov (United States)

1992-03-01

passenger ship destination, and tourist attraction. San Francisco’s location and cultural and recreational opportunities make it a prime tourism center...equestrians, she said. C-52 m% smm : - TUESDAY, JUNE 19,1990 * . COPYKIGHT 1*90/THE TIMES MlRkOX COMPANY /CC/1 JO PAGES P. A-l, 22, 23 Complex

Comparison of SANS instruments at reactors and pulsed sources

International Nuclear Information System (INIS)

Thiyagarajan, P.; Epperson, J.E.; Crawford, R.K.; Carpenter, J.M.; Hjelm, R.P. Jr.

1992-01-01

Small angle neutron scattering is a general purpose technique to study long range fluctuations and hence has been applied in almost every field of science for material characterization. SANS instruments can be built at steady state reactors and at the pulsed neutron sources where time-of-flight (TOF) techniques are used. The steady state instruments usually give data over small q ranges and in order to cover a large q range these instruments have to be reconfigured several times and SANS measurements have to be made. These instruments have provided better resolution and higher data rates within their restricted q ranges until now, but the TOF instruments are now developing to comparable performance. The TOF-SANS instruments, by using a wide band of wavelengths, can cover a wide dynamic q range in a single measurement. This is a big advantage for studying systems that are changing and those which cannot be exactly reproduced. This paper compares the design concepts and performances of these two types of instruments

Volcano hazards in the San Salvador region, El Salvador

Science.gov (United States)

Major, J.J.; Schilling, S.P.; Sofield, D.J.; Escobar, C.D.; Pullinger, C.R.

2001-01-01

San Salvador volcano is one of many volcanoes along the volcanic arc in El Salvador (figure 1). This volcano, having a volume of about 110 cubic kilometers, towers above San Salvador, the country’s capital and largest city. The city has a population of approximately 2 million, and a population density of about 2100 people per square kilometer. The city of San Salvador and other communities have gradually encroached onto the lower flanks of the volcano, increasing the risk that even small events may have serious societal consequences. San Salvador volcano has not erupted for more than 80 years, but it has a long history of repeated, and sometimes violent, eruptions. The volcano is composed of remnants of multiple eruptive centers, and these remnants are commonly referred to by several names. The central part of the volcano, which contains a large circular crater, is known as El Boquerón, and it rises to an altitude of about 1890 meters. El Picacho, the prominent peak of highest elevation (1960 meters altitude) to the northeast of the crater, and El Jabali, the peak to the northwest of the crater, represent remnants of an older, larger edifice. The volcano has erupted several times during the past 70,000 years from vents central to the volcano as well as from smaller vents and fissures on its flanks [1] (numerals in brackets refer to end notes in the report). In addition, several small cinder cones and explosion craters are located within 10 kilometers of the volcano. Since about 1200 A.D., eruptions have occurred almost exclusively along, or a few kilometers beyond, the northwest flank of the volcano, and have consisted primarily of small explosions and emplacement of lava flows. However, San Salvador volcano has erupted violently and explosively in the past, even as recently as 800 years ago. When such eruptions occur again, substantial population and infrastructure will be at risk. Volcanic eruptions are not the only events that present a risk to local

Implementation of an Online Climate Science Course at San Antonio College

Science.gov (United States)

Reyes, R.; Strybos, J.

2016-12-01

San Antonio College (SAC) plans to incorporate an online climate science class into the curriculum with a focus on local weather conditions and data. SAC is part of a network of five community colleges based around San Antonio, Texas, has over 20,000 students enrolled, and its student population reflects the diversity in ethnicity, age and gender of the San Antonio community. The college understands the importance of educating San Antonio residents on climate science and its complexities. San Antonio residents are familiar with weather changes and extreme conditions. The region has experienced an extreme drought, including water rationing in the city. Then, this year's El Niño intensified expected annual rainfalls and flash floods. The proposed climate science course will uniquely prepare students to understand weather data and the evidence of climate change impacting San Antonio at a local level. This paper will discuss the importance and challenges of introducing the new climate science course into the curriculum, and the desired class format that will increase the course's success. Two of the most significant challenges are informing students about the value of this class and identifying the best teaching format. Additionally, measuring and monitoring enrollment will be essential to determine the course performance and success. At the same time, Alamo Colleges is modifying the process of teaching online classes and is officially working to establish an online college. Around 23% of students enrolled in SAC offered courses are currently enrolled in online courses only, representing an opportunity to incorporate the climate science class as an online course. Since the proposed course will be using electronic textbooks and online applications to access hyperlocal weather data, the class is uniquely suited for online students.

SANS study of three-layer micellar particles

CERN Document Server

Plestil, J; Kuklin, A I; Cubitt, R

2002-01-01

Three-layer nanoparticles were prepared by polymerization of methyl methacrylate (MMA) in aqueous micellar solutions of poly(methyl methacrylate)-block-poly(methacrylic acid) (PMMA-b-PMA) and polystyrene-block-poly(methacrylic acid) (PS-b-PMA). The resulting polymer forms a layer on the core surface of the original micelles. SANS curves were fitted using an ellipsoidal (PMMA/PMMA/PMA) or spherical (PS/PMMA/PMA) model for the particle core. The particle size (for the presented series of the PMMA/PMMA/PMA particles, the core semiaxes ranged from 87 to 187 A and the axis ratio was about 6) can be finely tuned by variation of monomer concentration. Time-resolved SANS experiments were carried out to describe the growth of the PS/PMMA/PMA particles during polymerization. (orig.)

Identifying clinically meaningful symptom response cut-off values on the SANS in predominant negative symptoms.

Science.gov (United States)

Levine, Stephen Z; Leucht, Stefan

2013-04-01

The treatment and measurement of negative symptoms are currently at issue in schizophrenia, but the clinical meaning of symptom severity and change is unclear. To offer a clinically meaningful interpretation of severity and change scores on the Scale for the Assessment of Negative Symptoms (SANS). Patients were intention-to-treat participants (n=383) in two double-blind randomized placebo-controlled clinical trials that compared amisulpride with placebo for the treatment of predominant negative symptoms. Equipercentile linking was used to examine extrapolation from (a) CGI-S to SANS severity ratings, and (b) CGI-I to SANS percentage change (n=383). Linking was conducted at baseline, 8-14 days, 28-30 days, and 56-60 days of the trials. Across visits, CGI-S ratings of 'not ill' linked to SANS scores of 0-13, and ranged to 'extreme' ratings that linked to SANS scores of 102-105. The relationship between the CGI-S and the SANS severity scores assumed a linear trend (1=0-13, 2=15-56, 3=37-61, 4=49-66, 5=63-75, 6=79-89, 7=102-105). Similarly the relationship between CGI-I ratings and SANS percentage change followed a linear trend. For instance, CGI-I ratings of 'very much improved' were linked to SANS percent changes of -90 to -67, 'much improved' to -50 to -42, and 'minimally improved' to -21 to -13. The current results uniquely contribute to the debate surrounding negative symptoms by providing clinical meaning to SANS severity and change scores and so offer direction regarding clinically meaningful response cut-off scores to guide treatment targets of predominant negative symptoms. Copyright © 2013 Elsevier B.V. All rights reserved.

Characterization of the Drosophila ortholog of the human Usher Syndrome type 1G protein sans.

Directory of Open Access Journals (Sweden)

Fabio Demontis

Full Text Available BACKGROUND: The Usher syndrome (USH is the most frequent deaf-blindness hereditary disease in humans. Deafness is attributed to the disorganization of stereocilia in the inner ear. USH1, the most severe subtype, is associated with mutations in genes encoding myosin VIIa, harmonin, cadherin 23, protocadherin 15, and sans. Myosin VIIa, harmonin, cadherin 23, and protocadherin 15 physically interact in vitro and localize to stereocilia tips in vivo, indicating that they form functional complexes. Sans, in contrast, localizes to vesicle-like structures beneath the apical membrane of stereocilia-displaying hair cells. How mutations in sans result in deafness and blindness is not well understood. Orthologs of myosin VIIa and protocadherin 15 have been identified in Drosophila melanogaster and their genetic analysis has identified essential roles in auditory perception and microvilli morphogenesis, respectively. PRINCIPAL FINDINGS: Here, we have identified and characterized the Drosophila ortholog of human sans. Drosophila Sans is expressed in tubular organs of the embryo, in lens-secreting cone cells of the adult eye, and in microvilli-displaying follicle cells during oogenesis. Sans mutants are viable, fertile, and mutant follicle cells appear to form microvilli, indicating that Sans is dispensable for fly development and microvilli morphogenesis in the follicle epithelium. In follicle cells, Sans protein localizes, similar to its vertebrate ortholog, to intracellular punctate structures, which we have identified as early endosomes associated with the syntaxin Avalanche. CONCLUSIONS: Our work is consistent with an evolutionary conserved function of Sans in vesicle trafficking. Furthermore it provides a significant basis for further understanding of the role of this Usher syndrome ortholog in development and disease.

The aquatic annelid fauna of the San Marcos River headsprings, Hays County, Texas

Directory of Open Access Journals (Sweden)

McLean L.D. Worsham

2016-09-01

Full Text Available The San Marcos River in Central Texas has been well studied and has been demonstrated to be remarkably specious. Prior to the present study, research on free-living invertebrates in the San Marcos River only dealt with hard bodied taxa with the exception of the report of one gastrotrich, and one subterranean platyhelminth that only incidentally occurs in the head spring outflows. The remainder of the soft-bodied metazoan fauna that inhabit the San Marcos River had never been studied. Our study surveyed the annelid fauna and some other soft-bodied invertebrates of the San Marcos River headsprings. At least four species of Hirudinida, two species of Aphanoneura, one species of Branchiobdellida, and 11 (possibly 13 species of oligochaetous clitellates were collected. Other vermiform taxa collected included at least three species of Turbellaria and one species of Nemertea. We provide the results of the first survey of the aquatic annelid fauna of the San Marcos Springs, along with a dichotomous key to these annelids that includes photos of some representative specimens, and line drawings to elucidate potentially confusing diagnostic structures.

The aquatic annelid fauna of the San Marcos River headsprings, Hays County, Texas

Science.gov (United States)

Worsham, McLean L. D.; Gibson, Randy; Huffman, David G.

2016-01-01

Abstract The San Marcos River in Central Texas has been well studied and has been demonstrated to be remarkably specious. Prior to the present study, research on free-living invertebrates in the San Marcos River only dealt with hard bodied taxa with the exception of the report of one gastrotrich, and one subterranean platyhelminth that only incidentally occurs in the head spring outflows. The remainder of the soft-bodied metazoan fauna that inhabit the San Marcos River had never been studied. Our study surveyed the annelid fauna and some other soft-bodied invertebrates of the San Marcos River headsprings. At least four species of Hirudinida, two species of Aphanoneura, one species of Branchiobdellida, and 11 (possibly 13) species of oligochaetous clitellates were collected. Other vermiform taxa collected included at least three species of Turbellaria and one species of Nemertea. We provide the results of the first survey of the aquatic annelid fauna of the San Marcos Springs, along with a dichotomous key to these annelids that includes photos of some representative specimens, and line drawings to elucidate potentially confusing diagnostic structures. PMID:27853397

High intensity multi beam design of SANS instrument for Dhruva reactor

Energy Technology Data Exchange (ETDEWEB)

Abbas, Sohrab, E-mail: abbas@barc.gov.in; Aswal, V. K. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Désert, S. [Laboratoire Leon Brillouin, CEA, Saclay, 91191 (France)

2016-05-23

A new and versatile design of Small Angle Neutron Scattering (SANS) instrument based on utilization of multi-beam is presented. The multi-pinholes and multi-slits as SANS collimator for medium flux Dhruva rearctor have been proposed and their designs have been validated using McStas simulations. Various instrument configurations to achieve different minimum wave vector transfers in scattering experiments are envisioned. These options enable smooth access to minimum wave vector transfers as low as ~ 6×10{sup −4} Å{sup −1} with a significant improvement in neutron intensity, allowing faster measurements. Such angularly well defined and intense neutron beam will allow faster SANS studies of agglomerates larger than few tens of nm.

San Francisco-Pacifica Coast Landslide Susceptibility 2011

Data.gov (United States)

California Natural Resource Agency — The San Francisco-Pacifica Coast grid map was extracted from the California Geological Survey Map Sheet 58 that covers the entire state of California and originally...

75 FR 59285 - Endangered and Threatened Wildlife and Plants; Permit, San Luis Obispo County, CA

Science.gov (United States)

2010-09-27

...] Endangered and Threatened Wildlife and Plants; Permit, San Luis Obispo County, CA AGENCY: U.S. Fish and... project in the community of Los Osos, San Luis Obispo County, California. We invite comments from the... community of Los Osos, San Luis Obispo County, California. The parcel is legally described as Assessor...

San Francisco Bay Area Baseline Trash Loading Summary Results, San Francisco Bay Area CA, 2012, US EPA Region 9

Data.gov (United States)

U.S. Environmental Protection Agency — The San Francisco Bay Area stormwater permit sets trash control guidelines for discharges through the storm drain system. The permit covers Alameda, Contra Costa,...

Chlorinated hydrocarbon pesticides and polychlorinated biphenyls in sediment cores from San Francisco Bay

Science.gov (United States)

Venkatesan, M.I.; De Leon, R. P.; VanGeen, A.; Luoma, S.N.

1999-01-01

Sediment cores of known chronology from Richardson and San Pablo Bays in San Francisco Bay, CA, were analyzed for a suite of chlorinated hydrocarbon pesticides and polychlorinated biphenyls to reconstruct a historic record of inputs. Total DDTs (DDT = 2,4'- and 4,4'-dichlorodiphenyltrichloroethane and the metabolites, 2,4'- and 4,4'-DDE, -DDD) range in concentration from 4-21 ng/g and constitute a major fraction (> 84%) of the total pesticides in the top 70 cm of Richardson Bay sediment. A subsurface maximum corresponds to a peak deposition date of 1969-1974. The first measurable DDT levels are found in sediment deposited in the late 1930's. The higher DDT inventory in the San Pablo relative to the Richardson Bay core probably reflects the greater proximity of San Pablo Bay to agricultural activities in the watershed of the Sacramento and San Joaquin rivers. Total polychlorinated biphenyls (PCBs) occur at comparable levels in the two Bays (inventories in San Pablo Bay are about a factor of four higher in the last four decades than in Richardson Bay, suggesting a distribution of inputs not as strongly weighed towards the upper reaches of the estuary as DDTs. The shallower subsurface maximum in PCBs compared to DDT in the San Pablo Bay core is consistent with the imposition of drastic source control measures four these constituents in 1970 and 1977 respectively. The observed decline in DDT and PCB levels towards the surface of both cores is consistent with a dramatic drop in the input of these pollutants once the effect of sediment resuspension and mixing is taken into account.

Characterization of aerosols in the Metropolitan Area of San Jose

International Nuclear Information System (INIS)

Mejias Perez, J.A.

1997-07-01

The objective of the present study, was to elaborate a profile of the contamination by private matter and to characterize the aerosols collected in the Metropolitan Area of San Jose (Costa Rica). For that, a campaign of sampling was carried out in three points of the city of San Jose, differentiated by there degree of activity: Center of San Jose (Central Station of Firemen), San Isidro of Coronado -Canton of Vasquez of Coronado- (Municipality) and Escazu (Municipality). Such campaign was carried out from April 4 to July 4, 1996 (transition summer-winter), and in two periods of time of 8 hours: 8 a.m. to 4 p.m. and of 8 p.m. to 4 a.m. The aerosols were collected utilizing Gent Pm-10 samplers, in filters of polycarbonate of 0,4 μm and 8 μm in cascade, with a flow average of 15 L/min., and it determined the composition average of the present aerosols. The concentration of the majority of the anions were obtained by means of ionic chromatography of high resolution, and the main cations by spectrophotometry of atomic absorption with electro thermic atomization. The space-temporary variations of the concentrations were evaluated and their correlation with the meteorologic variable. (S. Grainger) [es

New record of Boa constrictor occidentalis Philippi, 1873 (Serpentes: Boidae) in San Juan province, Argentina

OpenAIRE

Martínez, Tomás; Rodriguez Muñoz, Melina; Galdeano, Ana; Acosta, Juan

2015-01-01

We document the first record of Boa constrictor in Valle Fértil department, San Juan province, Argentina. The specimen was collected and deposited in the herpetological collection of the Department of Biology, Universidad Nacional San Juan. This record extends the known distribution for this species in San Juan province by 105 km.

Choto-san in the treatment of vascular dementia: a double-blind, placebo-controlled study.

Science.gov (United States)

Terasawa, K; Shimada, Y; Kita, T; Yamamoto, T; Tosa, H; Tanaka, N; Saito, Y; Kanaki, E; Goto, S; Mizushima, N; Fujioka, M; Takase, S; Seki, H; Kimura, I; Ogawa, T; Nakamura, S; Araki, G; Maruyama, I; Maruyama, Y; Takaori, S

1997-03-01

In an earlier placebo-controlled study, we demonstrated that a kampo (Japanese herbal) medicine called Choto-san (Diao-Teng-San in Chinese) was effective in treating vascular dementia. To evaluate its efficacy using more objective criteria, we carried out a multi-center, double-blind study of Choto-san extract (7.5 g/day) and a placebo, each given three times a day for 12 weeks to patients suffering from this condition. The study enrolled and analyzed 139 patients, 50 males and 89 females, with a mean age of 76.6 years. Choto-san was statistically superior to the placebo in global improvement rating, utility rating, global improvement rating of subjective symptoms, global improvement rating of psychiatric symptoms and global improvement rating of disturbance in daily living activities. Such items as spontaneity of conversation, lack of facial expression, decline in simple mathematical ability, global intellectual ability, nocturnal delirium, sleep disturbance, hallucination or delusion, and putting on and taking off clothes were significantly improved at one or more evaluation points in those taking Choto-san compared to those taking the placebo. Furthermore, the change in revised version of Hasegawa's dementia scale from the beginning point in Choto-san group was tended to be higher than that in placebo group with no statistical significance. These results suggest that Choto-san is effective in the treatment of vascular dementia. Copyright © 1997 Gustav Fischer Verlag. Published by Elsevier GmbH.. All rights reserved.

Phosphorylation of the Usher syndrome 1G protein SANS controls Magi2-mediated endocytosis.

Science.gov (United States)

Bauß, Katharina; Knapp, Barbara; Jores, Pia; Roepman, Ronald; Kremer, Hannie; Wijk, Erwin V; Märker, Tina; Wolfrum, Uwe

2014-08-01

The human Usher syndrome (USH) is a complex ciliopathy with at least 12 chromosomal loci assigned to three clinical subtypes, USH1-3. The heterogeneous USH proteins are organized into protein networks. Here, we identified Magi2 (membrane-associated guanylate kinase inverted-2) as a new component of the USH protein interactome, binding to the multifunctional scaffold protein SANS (USH1G). We showed that the SANS-Magi2 complex assembly is regulated by the phosphorylation of an internal PDZ-binding motif in the sterile alpha motif domain of SANS by the protein kinase CK2. We affirmed Magi2's role in receptor-mediated, clathrin-dependent endocytosis and showed that phosphorylated SANS tightly regulates Magi2-mediated endocytosis. Specific depletions by RNAi revealed that SANS and Magi2-mediated endocytosis regulates aspects of ciliogenesis. Furthermore, we demonstrated the localization of the SANS-Magi2 complex in the periciliary membrane complex facing the ciliary pocket of retinal photoreceptor cells in situ. Our data suggest that endocytotic processes may not only contribute to photoreceptor cell homeostasis but also counterbalance the periciliary membrane delivery accompanying the exocytosis processes for the cargo vesicle delivery. In USH1G patients, mutations in SANS eliminate Magi2 binding and thereby deregulate endocytosis, lead to defective ciliary transport modules and ultimately disrupt photoreceptor cell function inducing retinal degeneration. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

Science.gov (United States)

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... the environment. San Joaquin Valley Unified Air Pollution Control District SJVUAPCD is an extreme...

Subsurface geometry of the San Andreas fault in southern California: Results from the Salton Seismic Imaging Project (SSIP) and strong ground motion expectations

Science.gov (United States)

Fuis, Gary S.; Bauer, Klaus; Goldman, Mark R.; Ryberg, Trond; Langenheim, Victoria; Scheirer, Daniel S.; Rymer, Michael J.; Stock, Joann M.; Hole, John A.; Catchings, Rufus D.; Graves, Robert; Aagaard, Brad T.

2017-01-01

The San Andreas fault (SAF) is one of the most studied strike‐slip faults in the world; yet its subsurface geometry is still uncertain in most locations. The Salton Seismic Imaging Project (SSIP) was undertaken to image the structure surrounding the SAF and also its subsurface geometry. We present SSIP studies at two locations in the Coachella Valley of the northern Salton trough. On our line 4, a fault‐crossing profile just north of the Salton Sea, sedimentary basin depth reaches 4 km southwest of the SAF. On our line 6, a fault‐crossing profile at the north end of the Coachella Valley, sedimentary basin depth is ∼2–3  km">∼2–3  km and centered on the central, most active trace of the SAF. Subsurface geometry of the SAF and nearby faults along these two lines is determined using a new method of seismic‐reflection imaging, combined with potential‐field studies and earthquakes. Below a 6–9 km depth range, the SAF dips ∼50°–60°">∼50°–60° NE, and above this depth range it dips more steeply. Nearby faults are also imaged in the upper 10 km, many of which dip steeply and project to mapped surface fault traces. These secondary faults may join the SAF at depths below about 10 km to form a flower‐like structure. In Appendix D, we show that rupture on a northeast‐dipping SAF, using a single plane that approximates the two dips seen in our study, produces shaking that differs from shaking calculated for the Great California ShakeOut, for which the southern SAF was modeled as vertical in most places: shorter‐period (TTfault.

First experiences with large SAN storage and Linux

International Nuclear Information System (INIS)

Wezel, Jos van; Marten, Holger; Verstege, Bernhard; Jaeger, Axel

2004-01-01

The use of a storage area network (SAN) with Linux opens possibilities for scalable and affordable large data storage and poses a new challenge for cluster computing. The GridKa center uses a commercial parallel file system to create a highly available high-speed data storage using a combination of Fibre Channel (SAN) and Ethernet (LAN) to optimize between data throughput and costs. This article describes the design, implementation and optimizations of the GridKa storage solution which will offer over 400 TB online storage for 600 nodes. Presented are some throughput measurements of one of the largest Linux-based parallel storage systems in the world

Medicinal use of plants by the peasant community of San Jacinto, northern Colombia Medicinal use of plants by the peasant community of San Jacinto, northern Colombia

Directory of Open Access Journals (Sweden)

Bonzani Renée M.

1999-11-01

Full Text Available I studied the medicinal use of plants by the peasant community of the town of San Jacinto, located in the savanna of Bolívar, northern Colombia. Fifty-five families, 138 genera, and 118 species were scientifically identified from 249 specimens collected of the modern-day vegetation of San Jacinto. From these, 198 uses were recorded for 190 (76% of the specimens. The 54 uses recorded for human medicine (27% and the five uses recorded for animal medicine (2% are discussed. Vernacular names, parts used, method of preparation, and medicinal uses are listed.Se presenta un estudio etnobotánico de la comunidad campesina del pueblo de San Jacinto, localizado en las sabanas de Bolívar, norte de Colombia. Se identificaron científicamente 55 familias, 138 géneros, y 118 especies con base en 249 especímenes recolectados de la vegetación de San Jacinto. De esos, se establecieron 198 usos para 190 (76% especímenes. Se presentan 54 usos para medicina humana (27% y cinco usos para medicina animal (2%. Se listan nombres vernáculos, partes usadas, método de preparación, y usos medicinales.

Effects of local geology on ground motion in the San Francisco Bay region, California—A continued study

Science.gov (United States)

Gibbs, James F.; Borcherdt, Roger D.

1974-01-01

intensity increments predicted for various geologic units are -0.3 for granite, 0.2 for Franciscan Formation, 0.6 for other pre-Tertiary, Tertiary bedrock, 0.8 for Santa Clara Formation, 1 .3 for older bay sediments, 2.4 for younger bay mud. These empirical relations, together with detailed geologic maps, delineate areas in the San Francisco Bay region of potentially high intensity from future earthquakes on either the San Andreas fault or the Hayward fault.

San Francisco Bay Interferometric Bathymetry: Area B

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — High resolution sonar data were collected over ultra-shallow areas of the San Francisco Bay estuary system. Bathymetric and acoustic backscatter data were collected...

78 FR 48046 - Safety Zone; Kuoni Destination Management Fireworks; San Diego, CA

Science.gov (United States)

2013-08-07

...-AA00 Safety Zone; Kuoni Destination Management Fireworks; San Diego, CA AGENCY: Coast Guard, DHS... waters of the San Diego Bay in support of the Kuoni Destination Management Fireworks Display on August 6... Guard's ability to protect the public from the potential hazards associated with fireworks displays...

Cuisine Preference of Local Tourists in San Juan, Batangas, Philippines

OpenAIRE

RYENE SELLINE B. KALALO; ANGELICA LYNTTE A. CABLAO; MARICRISS P. CABATAY; CHARISSA P. MANTAL; RHONALYN T. MANALO; SEVILLA S. FELICEN

2014-01-01

This study aimed to determine the cuisine preference of the local tourist in San Juan, Batangas. More specifically, it aimed to describe the demographic profile of local tourist; to identify the preferred cuisine by different restaurants; to determine the significant difference when group according to demographic profile; and to determine the cuisine preference of local tourists in San Juan, Batangas. The research design used the descriptive method because it is the most appropria...

A SANS study of capillary condensation in porous media

International Nuclear Information System (INIS)

Lin, M.; Glinka, C.; Sinna, S.; Huang, J.; Abeles, B.; Johnson, J.; Drake, J.

1990-01-01

The authors use small angle neutron scattering (SANS) to study the microstructure of porous Vycor glass and the capillary condensation of fluids in the medium. Using a chord distribution model, they can predict the structure factor measured by SANS. Excellent agreement with the data is obtained. The fitted parameters characterize quantitatively the porous structure before and during the process of condensation, and are in good agreement with isotherm measurements. However, at the latest stages of the process, when all the pores are nearly filled, the model can no longer describe the system

Facing the great disaster : How the men and women of the U.S. Geological Survey responded to the 1906 "San Francisco Earthquake"

Science.gov (United States)

Colvard, Elizabeth M.; Rogers, James

2006-01-01

It was the most devastating earthquake in California’s history. At 5:12 a.m. on April 18, 1906, the ground under the San Francisco Bay Area shook violently for more than 40 seconds. The magnitude 7.8 earthquake created a rupture along nearly 300 miles of the San Andreas Fault and was felt from southern Oregon to Los Angeles. Because the earthquake’s epicenter was just offshore from San Francisco, the impact on that city was catastrophic. Fragments of broken houses and buildings tumbled into the streets. The pipeline carrying water into the city was severed; fires triggered by broken gas mains raged out of control for 3 days. An area of almost 5 square miles in the heart of the city was destroyed by shaking and fire, and earthquake damage was widespread elsewhere. At least 3,000 people were killed, and 225,000 were left homeless. Drinking water, food, and supplies quickly became scarce.In 1906, the only permanent U.S. Geological Survey (USGS) office in California was the Pacific Division topographic mapping office in Sacramento, 70 miles up the Sacramento River from San Francisco Bay. The office had been established just 3 years earlier and was the only USGS office ever created for the sole function of topographic mapping. At the time of the earthquake, many USGS topographers were in Sacramento preparing for a summer of field work.Although moderate shaking was felt in Sacramento, then a town of about 30,000 people, detailed information about the earthquake was slow to reach the residents there. USGS topographic engineer George R. Davis, not knowing the full extent of the damage, was fearful that his 62-year-old father Edward Davis in San Francisco was caught up in the devastation. George therefore left Sacramento on the first train bound for the San Francisco Bay area. “He was very worried. The phones were down and he wasn’t sure whether or not the hotel his father was living in was damaged,” said George Davis’s daughter Anna (Davis) Rogers, then an

77 FR 48532 - Notice of Intent To Repatriate Cultural Items: San Diego State University, San Diego, CA

Science.gov (United States)

2012-08-14

... Management Program, in consultation with the appropriate Indian tribe, has determined that the cultural items... itself to be culturally affiliated with the cultural items may contact San Diego State University Archaeology Collections Management Program. DATES: Representatives of any Indian tribe that believes it has a...

Caracterización de las principales pesquerías del golfo San Jorge Patagonia, Argentina Characterization of the main fisheries in San Jorge Gulf, Patagonia, Argentina

Directory of Open Access Journals (Sweden)

María Eva Góngora

2012-03-01

Full Text Available En el golfo San Jorge se desarrollan varias actividades económicas de relevancia, entre ellas dos pesquerías industriales: la pesquería de merluza común (Merluccius hubbsi Marini, 1933 y la pesquería de langostino patagónico (Pleoticus muelleri Bate, 1888, ambas se solapan espacial y temporalmente. En la pesquería de merluza del golfo San Jorge opera una flota fresquera de altura, compuesta por unas 20 embarcaciones, y una flota costera, compuesta por unas 30 embarcaciones. En esta pesquería se pesca alrededor del 10% de lo capturado en el stock sur de merluza. En la pesquería de langostino del golfo San Jorge opera una flota congeladora tangonera compuesta por 80 embarcaciones, responsable de más del 75% de los desembarques de langostino realizados en la República Argentina. Ambas pesquerías tienen como principal problema la captura incidental de merluza, en una de sus principales áreas de cría. En el presente trabajo se describe el manejo actual en las pesquerías del golfo San Jorge, el cual consiste principalmente en cierres espaciales y temporales para la pesca de langostino, y zonificaciones por estrato de flota para la merluza. En ninguna de las dos pesquerías descriptas se han tomado medidas que reduzcan eficazmente la captura incidental.In San Jorge Gulf, several important economic activities are developed, including two industrial fisheries: hake (Merluccius hubbsi Marini, 1933 and Argentine red shrimp (Pleoticus muelleri Bate, 1888. Both overlap spatially and temporally. The San Jorge Gulf hake fishery consists of a high-seas ice trawler fleet (n = 20 fishing vessels and a coastal fleet (n = 30 fishing vessels. These fisheries capture about 10% of the catch of the southern hake stock. The Argentine red shrimp fishery consists of a double-beam trawler fleet with 80 freezer vessels, responsible for more than 75% of shrimp landings in Argentina. The main problem of both fisheries is the bycatch of hake in one of its

Estudio constructivo y análisis de la Sacristía de la iglesia de San Miguel y San Sebastián

OpenAIRE

RUBIO MUÑOZ, RUBÉN

2017-01-01

La iglesia de San Miguel y San Sebastián, de Cardona y Pertusa, es un edificio erigido en el siglo XVIII, con anterioridad a la creación de la Academia de Bellas Artes, en que se produce la transición de la arquitectura y los oficios relacionados con la construcción. La Sacristía de la citada iglesia, de planta de cruz griega y con cúpula centra, es uno de los mejores ejemplos de la arquitectura del periodo y que, por desgracia, poco conocida. En el TFG se pretende realizar un exhaustivo l...

San Rafael mining and fabrication complex today

International Nuclear Information System (INIS)

Navarra, Pablo; Aldebert, Sergio R.

2005-01-01

In Mendoza province, 35 km West San Rafael city, is located a CNEA installation for uranium ore extraction and concentration: the San Rafael Mining and Fabrication Complex. By the middle of the nineties, as a consequence of the very low prices of uranium concentrate in the international market and of the high internal production costs, uranium extraction was stopped. To day, the international price of the concentrate had a very important increase and the Government has decided the completion of the Atucha II Nuclear Power Station construction. Moreover, studies have been started for new nuclear power plants. In such circumstances the reactivation of the Complex will make sure the uranium supply for our nuclear power stations, contributing to the improvement of the energy generation mix in our country. (author) [es

SANS and TEM studies of carbide precipitation and creep damage in type 304 stainless steel

International Nuclear Information System (INIS)

Yoo, M.H.; Ogle, J.C.; Schneibel, J.H.; Swindeman, R.W.

1984-01-01

Small-angle neutron scattering (SANS) and transmission electron microscopy (TEM) studies were performed to characterize the carbide (M 23 C 6 ) precipitation and creep damage induced in type 304 stainless steel in the primary creep stage. The size distribution of matrix carbides evaluated from SANS analyses was consistent with TEM data, and the expected accelerated kinetics of precipitation under applied stress was confirmed. Additional SANS measurements after the postcreep solution annealing were made in order to differentiate cavities from the carbides. Potential advantages and difficulties associated with characterization of creep-induced cavitation by the SANS techniques are discussed

Age and paleoenvironment of the imperial formation near San Gorgonio Pass, Southern California

Science.gov (United States)

McDougall, K.; Poore, R.Z.; Matti, J.

1999-01-01

Microfossiliferous marine sediments of the Imperial Formation exposed in the Whitewater and Cabazon areas, near San Gorgonio Pass, southern California, are late Miocene in age and were deposited at intertidal to outer neritic depths, and possibly upper bathyal depths. A late Miocene age of 7.4 to >6.04 Ma is based on the ranges of age-diagnostic benthic foraminifers (Cassidulina delicata and Uvigerina peregrina), planktic foraminifers (Globigerinoides obliquus, G. extremus, and Globigerina nepenthes; zones N17-N19), and calcareous nannoplankton (Discoaster brouweri, D. aff. D. surculus, Reticulofenestra pseudoumbilicata, Sphenolithus abies, and S. neoabies; zones CN9a-CN11) coupled with published K/Ar dates from the underlying Coachella Formation (10.1 ?? 1.2 Ma; Peterson, 1975) and overlying Painted Hill Formation (6.04 ?? 0.18 and 5.94 ?? 0.18 Ma; J. L. Morton in Matti and others, 1985 and Matti and Morton, 1993). Paleoecologic considerations (sea-level fluctuations and paleotemperature) restrict the age of the Imperial Formation to 6.5 through 6.3 Ma. Benthic foraminiferal assemblages indicate that the Imperial Formation in the Whitewater and Cabazon sections accumulated at inner neritic to outer neritic (0-152 m) and possibly upper bathyal (152-244 m) depths. Shallowing to inner neritic depths occurred as the upper part of the section was deposited. This sea-level fluctuation corresponds to a global highstand at 6.3 Ma (Haq and others, 1987). Planktic foraminifers suggest an increase in surface-water temperatures upsection. A similar increase in paleotemperatures is interpreted for the North Pacific from 6.5 to 6.3 Ma (warm interval W10 of Barron and Keller, 1983). Environmental contrasts between the Whitewater and Cabazon sections of the Imperial Formation provide evidence for right-lateral displacements on the Banning fault, a late Miocene strand of the San Andreas fault system. The Cabazon section lies south of the Banning fault, and has been displaced west

33 CFR 165.1120 - Security Zone; Naval Amphibious Base, San Diego, CA.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone; Naval Amphibious Base, San Diego, CA. 165.1120 Section 165.1120 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 165.1120 Security Zone; Naval Amphibious Base, San Diego, CA. (a) Location. The following area is a...

Aggregate Settling Velocities in San Francisco Estuary Margins

Science.gov (United States)

Allen, R. M.; Stacey, M. T.; Variano, E. A.

2015-12-01

One way that humans impact aquatic ecosystems is by adding nutrients and contaminants, which can propagate up the food web and cause blooms and die-offs, respectively. Often, these chemicals are attached to fine sediments, and thus where sediments go, so do these anthropogenic influences. Vertical motion of sediments is important for sinking and burial, and also for indirect effects on horizontal transport. The dynamics of sinking sediment (often in aggregates) are complex, thus we need field data to test and validate existing models. San Francisco Bay is well studied and is often used as a test case for new measurement and model techniques (Barnard et al. 2013). Settling velocities for aggregates vary between 4*10-5 to 1.6*10-2 m/s along the estuary backbone (Manning and Schoellhamer 2013). Model results from South San Francisco Bay shoals suggest two populations of settling particles, one fast (ws of 9 to 5.8*10-4 m/s) and one slow (ws of Brand et al. 2015). While the open waters of San Francisco Bay and other estuaries are well studied and modeled, sediment and contaminants often originate from the margin regions, and the margins remain poorly characterized. We conducted a 24 hour field experiment in a channel slough of South San Francisco Bay, and measured settling velocity, turbulence and flow, and suspended sediment concentration. At this margin location, we found average settling velocities of 4-5*10-5 m/s, and saw settling velocities decrease with decreasing suspended sediment concentration. These results are consistent with, though at the low end of, those seen along the estuary center, and they suggest that the two population model that has been successful along the shoals may also apply in the margins.

Cianobacterias del embalse San Roque (Córdoba, Argentina Cyanobacteria of the San Roque reservoir (Córdoba, Argentina

Directory of Open Access Journals (Sweden)

Inés Claudia Daga

2011-12-01

Full Text Available Este trabajo es una contribución al conocimiento de las cianobacterias presentes en el embalse San Roque y forma parte de un estudio integral de la flora algal del mencionado embalse. Se citan 24 taxa correspondientes a los Ordenes Chroococcales (11, Nostocales (8 y Oscillatoriales (5. Synechocystis aquatilis, Gloeocapsa rupestris, Gomphosphaeria aponina, Chamaesiphon incrustans f. incrustans, Scytonema crispum, Tolypothrix distorta, Gloeotrichia pisum, Calothrix fusca, Trichodesmium lacustre, Geitlerinema splendidum, Lyngbya aestuarii y Borzia trilocularis son nuevas citas para la zona de estudio.This work is a contribution to the knowledge of the Cyanobacteria present in the San Roque reservoir and forms a part of an integral study of its algal flora. Twenty-four taxa are described and ilustrated: 11 Chroococcales, 8 Nostocales, and 5 Oscillatoriales. Synechocystis aquatilis, Gloeocapsa rupestris, Gomphosphaeria aponina, Chamaesiphon incrustans f. incrustans, Scytonema crispum, Tolypothrix distorta, Gloeotrichia pisum, Calothrix fusca, Trichodesmium lacustre, Geitlerinema splendidum, Lyngbya aestuarii and Borzia trilocularis.

SOCIEDAD, PAZ Y GUERRA EN SAN AGUSTÍN

Directory of Open Access Journals (Sweden)

MIGUEL VERGARA VILLALOBOS

2017-12-01

Full Text Available Este trabajo analiza las nociones de sociedad, paz y guerra, en La ciudad de Dios, de San Agustín, a la que nos referimos principalmente según la edición bilingüe preparada por José Morán (1965. En una primera parte, a modo de introducción, se expone el argumento general del libro y se explica la teoría de las dos ciudades, la terrena y la de Dios. Enseguida se analiza la noción de sociedad, que se fundamenta en la justicia y en el interés común como camino para alcanzar la paz. Esto nos lleva a examinar la justicia, que para San Agustín es un concepto fundamental tanto en la ciudad terrena como en la ciudad de Dios. Teniendo este marco conceptual en cuanto la sociedad y la autoridad, se entra a discutir la paz, que representa uno de los aspectos centrales de la obra que comentamos. En contraste y como oposición a la paz se analiza la guerra; para nalizar con un tema cuyo origen clásicamente se atribuye a San Agustín, cual es la guerra justa.

The san san game as didatic resource of support in the discussions about regulatory nutrients in elementary education

Directory of Open Access Journals (Sweden)

Bárbara Della Antonia

2017-11-01

Full Text Available Leisure activities are used in the learning teaching process of the different areas of knowledge, to promote learning spontaneously and fun. For the area of Agrarian Sciences, which is a multidisciplinary area of study that can be approached from basic education to higher education, it is necessary to study the elaboration of didactic resources. Thus, this study aimed at the development of a didactic game in the field of agricultural sciences aimed at elementary education, whose strategy is to help in the understanding of contents related to the chemical composition of foods, focusing on regulatory nutrients. The game SAN SAN was applied and evaluated with elementary school students of a public school, bringing to the end of the process, positive results in the sense of motivation to study the subject, involvement of students in classes and contribution with an effective didactic resource.

Two-Phase Exhumation of the Santa Rosa Mountains: Low- and High-Angle Normal Faulting During Initiation and Evolution of the Southern San Andreas Fault System

Science.gov (United States)

Mason, Cody C.; Spotila, James A.; Axen, Gary; Dorsey, Rebecca J.; Luther, Amy; Stockli, Daniel F.

2017-12-01

Low-angle detachment fault systems are important elements of oblique-divergent plate boundaries, yet the role detachment faulting plays in the development of such boundaries is poorly understood. The West Salton Detachment Fault (WSDF) is a major low-angle normal fault that formed coeval with localization of the Pacific-North America plate boundary in the northern Salton Trough, CA. Apatite U-Th/He thermochronometry (AHe; n = 29 samples) and thermal history modeling of samples from the Santa Rosa Mountains (SRM) reveal that initial exhumation along the WSDF began at circa 8 Ma, exhuming footwall material from depths of >2 to 3 km. An uplifted fossil (Miocene) helium partial retention zone is present in the eastern SRM, while a deeper crustal section has been exhumed along the Pleistocene high-angle Santa Rosa Fault (SFR) to much higher elevations in the southwest SRM. Detachment-related vertical exhumation rates in the SRM were 0.15-0.36 km/Myr, with maximum fault slip rates of 1.2-3.0 km/Myr. Miocene AHe isochrons across the SRM are consistent with northeast crustal tilting of the SRM block and suggest that the post-WSDF vertical exhumation rate along the SRF was 1.3 km/Myr. The timing of extension initiation in the Salton Trough suggests that clockwise rotation of relative plate motions that began at 8 Ma is associated with initiation of the southern San Andreas system. Pleistocene regional tectonic reorganization was contemporaneous with an abrupt transition from low- to high-angle faulting and indicates that local fault geometry may at times exert a fundamental control on rock uplift rates along strike-slip fault systems.

77 FR 25128 - Amended Land Management Plans for the Angeles, Cleveland, Los Padres, and San Bernardino National...

Science.gov (United States)

2012-04-27

..., Los Padres, and San Bernardino National Forests, California AGENCY: Forest Service, USDA. ACTION... amendment of the Land Management Plans for the Angeles, Cleveland, Los Padres, and San Bernardino National... Angeles, Cleveland, Los Padres, and San Bernardino National Forests, collectively, ``four forests...

October 1986 San Salvador, El Salvador Images

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — At least 1,000 people killed, 10,000 injured, 200,000 homeless and severe damage in the San Salvador area. About 50 fatalities were the result of landslides in the...

San Diego Littoral Cell CRSMP Receiver Sites 2009

Data.gov (United States)

California Natural Resource Agency — A total of 27 possible placement sites (some with multiple placement footprints) are incorporated into this San Diego Coastal Regional Sediment Management Plan to...

San Diego Littoral Cell CRSMP Receiver Sites 2009

Data.gov (United States)

California Department of Resources — A total of 27 possible placement sites (some with multiple placement footprints) are incorporated into this San Diego Coastal Regional Sediment Management Plan to...

Magnetotelluric data collected to characterize aquifers in the San Luis Basin, New Mexico

Science.gov (United States)

Ailes, Chad E.; Rodriguez, Brian D.

2015-01-01

The U.S. Geological Survey is conducting a series of multidisciplinary studies of the San Luis Basin as part of the Geologic Framework of Rio Grande Basins project. Detailed geologic mapping, high-resolution airborne magnetic surveys, gravity surveys, magnetotelluric surveys, and hydrologic and lithologic data are being used to better understand the aquifers in the San Luis Basin. This report describes one north-south and two east-west regional magnetotelluric sounding profiles, acquired in June of 2010 and July and August of 2011, across the San Luis Basin in northern New Mexico. No interpretation of the data is included.

Waterbird nest monitoring program in San Francisco Bay (2005-10)

Science.gov (United States)

Ackerman, Joshua T.; Herzog, Mark P.

2012-01-01

Historically, Forster’s Terns (Sterna forsteri), American Avocets (Recurvirostra americana), and Black-necked Stilts (Himantopus mexicanus) were uncommon residents of San Francisco Bay, California (Grinnell and others, 1918; Grinnell and Wythe, 1927; Sibley, 1952). Presently, however, avocets and stilts are the two most abundant breeding shorebirds in San Francisco Bay (Stenzel and others, 2002; Rintoul and others, 2003). More than 4,000 avocets and 1,000 stilts, roughly 20 percent of their San Francisco Bay wintering populations, breed within the estuary, making San Francisco Bay the largest breeding area for these species on the Pacific Coast (Stenzel and others, 2002; Rintoul and others, 2003). Forster’s Terns were first observed breeding in the San Francisco Bay in 1948 (110 nests); they had increased to over 4000 individuals by the 1980s (Sibley, 1952; Gill, 1977; Harvey and others, 1992; Carter and others, 1990) and were estimated at 2000–3000 for 1998–2002; (Strong and others, 2004).It is hypothesized that the relatively large size of the current waterbird breeding populations is a result of the creation of artificial salt evaporation ponds from the 1930s through the 1950s (Gill, 1977; Goals Project, 1999). Until recently, these salt ponds and associated islands used by waterbirds for nesting have been managed relatively similarly and have supported large breeding waterbird populations. Recently, the South Bay Salt Pond Restoration Project has implemented plans to convert 50–90 percent of the 15,000 acres of salt ponds in the South San Francisco Bay back to tidal marsh habitat. Therefore, there is concern that the Restoration Project, while benefiting other native species, could negatively influence local breeding populations of waterbirds that are reliant on salt pond habitats for both breeding and foraging. A primary goal of the South Bay Salt Pond Restoration Project is to maintain current breeding waterbird populations (South Bay Salt Pond Long

4D stress evolution models of the San Andreas Fault System: Investigating time- and depth-dependent stress thresholds over multiple earthquake cycles

Science.gov (United States)

Burkhard, L. M.; Smith-Konter, B. R.

2017-12-01

4D simulations of stress evolution provide a rare insight into earthquake cycle crustal stress variations at seismogenic depths where earthquake ruptures nucleate. Paleoseismic estimates of earthquake offset and chronology, spanning multiple earthquakes cycles, are available for many well-studied segments of the San Andreas Fault System (SAFS). Here we construct new 4D earthquake cycle time-series simulations to further study the temporally and spatially varying stress threshold conditions of the SAFS throughout the paleoseismic record. Interseismic strain accumulation, co-seismic stress drop, and postseismic viscoelastic relaxation processes are evaluated as a function of variable slip and locking depths along 42 major fault segments. Paleoseismic earthquake rupture histories provide a slip chronology dating back over 1000 years. Using GAGE Facility GPS and new Sentinel-1A InSAR data, we tune model locking depths and slip rates to compute the 4D stress accumulation within the seismogenic crust. Revised estimates of stress accumulation rate are most significant along the Imperial (2.8 MPa/100yr) and Coachella (1.2 MPa/100yr) faults, with a maximum change in stress rate along some segments of 11-17% in comparison with our previous estimates. Revised estimates of earthquake cycle stress accumulation are most significant along the Imperial (2.25 MPa), Coachella (2.9 MPa), and Carrizo (3.2 MPa) segments, with a 15-29% decrease in stress due to locking depth and slip rate updates, and also postseismic relaxation from the El Mayor-Cucapah earthquake. Because stress drops of major strike-slip earthquakes rarely exceed 10 MPa, these models may provide a lower bound on estimates of stress evolution throughout the historical era, and perhaps an upper bound on the expected recurrence interval of a particular fault segment. Furthermore, time-series stress models reveal temporally varying stress concentrations at 5-10 km depths, due to the interaction of neighboring fault

Distribución del ocelote (Leopardus pardalis en San Luis Potosí, México Distribution of the ocelot (Leopardus pardalis in San Luis Potosí, Mexico

Directory of Open Access Journals (Sweden)

Jesús Manuel Martínez-Calderas

2011-09-01

Full Text Available Para definir la distribución geográfica del ocelote en el estado de San Luis Potosí, México, se obtuvieron nuevos registros de la especie. El estudio se realizó de enero de 2007 a abril de 2009. Se obtuvieron 41 registros de ocelotes por medio de entrevistas y trampeo-fotográfico. Los registros se localizaron en comunidades vegetales de selva baja caducifolia (37%, matorral submontano (22%, bosque de encino (15%, selva mediana (10%, selva alta perennifolia, bosque mesófilo de montaña, bosque de pino-encino y matorral desértico micrófilo (10%. La presencia de ocelotes se ubicó en los municipios de Ciudad del Maíz, El Naranjo, Cerritos, Guadalcázar, San Nicolás Tolentino y Ciudad Valles en de elevaciones de 38 a 2 400 m snm. Los resultados de esta investigación sugieren una distribución del ocelote más hacia el oeste del estado respecto a su distribución original. El presente estudio definió nuevas regiones con presencia de ocelotes que pueden ser consideradas en el desarrollo de estrategias de conservación de la especie en el estado de San Luis Potosí.To determine the geographic distribution of ocelot in the state of San Luis Potosí, Mexico, we obtained new records. The study was conducted from January 2007 to April 2009. We recorded 41 ocelot records by interviews and camera-trapping. Ocelots records were located in tropical deciduous forest (37%, semitropical thornscrub (22%, oak forest (15%, tropical forest (10%, tall tropical deciduous forest, desert scrub, pine-oak forest and clouded forest (10%. Ocelot records were located in the municipalities of Ciudad del Maíz, El Naranjo, Cerritos, Guadalcazar, San Nicolás Tolentino and Ciudad Valles where the elevation ranged from 38 to 2 400 m. The evidence of this research suggests that ocelot range is more extended to the west than its original geographical range. This study defined new regions with presence of ocelots that may be considered to develop conservation strategies

76 FR 6491 - San Diego County Water Authority Subregional Natural Community Conservation Program/Habitat...

Science.gov (United States)

2011-02-04

...] San Diego County Water Authority Subregional Natural Community Conservation Program/Habitat Conservation Plan, San Diego and Riverside Counties, CA; Final Environmental Impact Statement and Habitat... also announce the availability of the Water Authority's Subregional Natural Community Conservation...

[Psychiatric Hospital San Juan de Dios. One hundred years later].

Science.gov (United States)

Cocula-León, Horacio

2014-01-01

Mental health and psychiatric diseases have always attracted people's and health authorities' attention due to its magical approach, the lack of knowledge that surrounds them, and, at the same time, the religious fear they provoke. Both have played an important role in the history of humanity, of public health politics, and of physicians. The places where psychiatric patients were treated are of historical interest, because through the historical knowledge we can identify an approach from the science and the health policies that prevailed in each age. At the beginning of the 20th century, it was developed in México a new model of hospital care attention to psychiatric patients. La Casa de Salud San Juan de Dios para Pacientes Alienados is an example; the concept "alienated patients" suggests a social and cultural perspective. This paper presents a chronological type description of one of the major institutions involved in mental health care in México. Similarly, it shows a review of the events that affected the religious order San Juan de Dios from 1901 to 2012, when the hospitaller order was reinstated in México and established the Casa de Salud San Juan de Dios para Pacientes Alienados in the town of Zapopan, Jalisco, institution that exists up to the present day and keeps participating in the mental health care in the state of Jalisco, with the current name of Servicios de Salud San Juan de Dios.

Microbial diversity in restored wetlands of San Francisco Bay

Energy Technology Data Exchange (ETDEWEB)

Theroux, Susanna [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Hartman, Wyatt [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; He, Shaomei [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Univ. of Wisconsin, Madison, WI (United States); Tringe, Susannah [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.

2013-12-09

Wetland ecosystems may serve as either a source or a sink for atmospheric carbon and greenhouse gases. This delicate carbon balance is influenced by the activity of belowground microbial communities that return carbon dioxide and methane to the atmosphere. Wetland restoration efforts in the San Francisco Bay-Delta region may help to reverse land subsidence and possibly increase carbon storage in soils. However, the effects of wetland restoration on microbial communities, which mediate soil metabolic activity and carbon cycling, are poorly studied. In an effort to better understand the underlying factors which shape the balance of carbon flux in wetland soils, we targeted the microbial communities in a suite of restored and historic wetlands in the San Francisco Bay-Delta region. Using DNA and RNA sequencing, coupled with greenhouse gas monitoring, we profiled the diversity and metabolic potential of the wetland soil microbial communities along biogeochemical and wetland age gradients. Our results show relationships among geochemical gradients, availability of electron acceptors, and microbial community composition. Our study provides the first genomic glimpse into microbial populations in natural and restored wetlands of the San Francisco Bay-Delta region and provides a valuable benchmark for future studies.

Solar Feasibility Study May 2013 - San Carlos Apache Tribe

Energy Technology Data Exchange (ETDEWEB)

Rapp, Jim [Parametrix; Duncan, Ken [San Carlos Apache Tribe; Albert, Steve [Parametrix

2013-05-01

The San Carlos Apache Tribe (Tribe) in the interests of strengthening tribal sovereignty, becoming more energy self-sufficient, and providing improved services and economic opportunities to tribal members and San Carlos Apache Reservation (Reservation) residents and businesses, has explored a variety of options for renewable energy development. The development of renewable energy technologies and generation is consistent with the Tribe’s 2011 Strategic Plan. This Study assessed the possibilities for both commercial-scale and community-scale solar development within the southwestern portions of the Reservation around the communities of San Carlos, Peridot, and Cutter, and in the southeastern Reservation around the community of Bylas. Based on the lack of any commercial-scale electric power transmission between the Reservation and the regional transmission grid, Phase 2 of this Study greatly expanded consideration of community-scale options. Three smaller sites (Point of Pines, Dudleyville/Winkleman, and Seneca Lake) were also evaluated for community-scale solar potential. Three building complexes were identified within the Reservation where the development of site-specific facility-scale solar power would be the most beneficial and cost-effective: Apache Gold Casino/Resort, Tribal College/Skill Center, and the Dudleyville (Winkleman) Casino.

2010 Northern San Francisco Bay Area Lidar: Portions of Alameda, Contra Costa, Marin, Napa, San Francisco, Solano, and Sonoma Counties

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This Light Detection and Ranging (LiDAR) dataset is a survey of northern San Francisco Bay, California. The project area consists of approximately 437 square miles...

Inteligencia emocional y vínculo laboral en trabajadores del Centro San Camilo Emotional intelligence and engagement in San Camilo Centre workers

Directory of Open Access Journals (Sweden)

Cristina Liébana Presa

2012-06-01

Full Text Available Las organizaciones están comprometidas desde hace tiempo con la promoción de la salud y del bienestar de los trabajadores. Con este referente se realizó el presente estudio; el objetivo fue describir y analizar las asociaciones que existen entre las variables inteligencia emocional y engagement. La población fueron 150 trabajadores del Centro San Camilo. Los instrumentos de evaluación utilizados son la escala de Inteligencia Emocional (EIE-33, la escala de Inteligencia Emocional (EIE-25, el Trait Meta-Mood Scale (TMMS-24 y cuestionario de Utrecht Work Engagement Scale (UWES. Es un estudio descriptivo correlacional. En los trabajadores del Centro San Camilo existe asociación entre la inteligencia emocional y el engagement. Así la inteligencia emocional, entendida como la capacidad para adquirir habilidades o competencias para la adaptación de las demandas profesionales, potencia un estado mental positivo relacionado con el trabajo y ello repercute en la calidad asistencial y en la salud de la población atendida.For some time organizations are committed with health promotion and workers welfare. Under this concern this study has been conducted; the aim was to describe and analyse the existing associations between emotional intelligence and engagement variables. The population were 150 workers from San Camilo Centre. The assessment instruments used were the scale of Emotional Intelligence (EIE-33, the scale of Emotional Intelligence (EIE-25, the Trait Meta-Mood Scale (TMMS-25 and the questionnaire of Utrecht Work Engagement Scale (UWES. It is a descriptive correlational study. In San Camilo Centre workers there is association between emotional intelligence and engagement. Emotional intelligence, understood as the capacity to acquire skills or competencies for the adaptation to professional demands thus enhances a positive mental state work-related and this affects the quality of care and the assisted population health.

Miocene and Pleistocene mollusks from San Andres Island (Caribbean Sea, Colombia) and Paleogeographic considerations

International Nuclear Information System (INIS)

Diaz M, Juan Manuel; Garcia Llano, Cesar Fernando

2010-01-01

San Andres Island is the largest emerged portion of the oceanic archipelago of San Andres and Providencia, southwestern Caribbean Sea; it originated as a coralline atoll during Miocene times. The central and highest part of the island consists of a calcareous crest, the San Andres Formation, formed by Neogene lagoonal and reefal deposits. This crest is surrounded by a calcareous platform of Pleistocene age (San Luis Formation) which emerges only along the island coast, whereas its most part is submerged and covered by a Recent reef complex. Fossil material of molluscs from these two formations was collected in various sites throughout the island and taxonomically identified. In the four sites sampled in the San Andres Formation, material belonging to 19 gastropod and 37 bivalve species was obtained, most of them relatively well represented in other geologic formations of the Caribbean region that are stratigraphically situated between the upper Miocene and the middle Pliocene. Some elements occurring in this formation, such as Ostrea haitiensis, Meretrix dariena and Siphocypraea henekeni, were widely distributed in the Caribbean Miocene Province. In the San Luis Formation, material belonging to 18 gastropod and 11 bivalve species was obtained, most of them also represented in the Recent molluscan fauna of the region. The estimated age of this formation is Sangamonian, hence corresponding to similar formations occurring in Grand Cayman, Jamaica, Hispaniola, the Netherlands Antilles and other Caribbean islands, with which it also shows a great similarity in the composition of the molluscan fauna.

Clinical Evaluation of Perspiration Reducing Effects of a Kampo Formula, Shigyaku-san, on Palmoplantar Hidrosis

Directory of Open Access Journals (Sweden)

Fumino Ninomiya

2008-01-01

Full Text Available Palmoplantar hidrosis is common in patients who are susceptible to strains on the autonomic nervous system, and stress and mental strain have been proven to produce sweating in this population. Shigyaku-san (Sini san, TJ-35: Tsumura & Co. is effective for relieving stagnation of ‘liver Qi and vital energy’ in traditional Chinese medicine theory; this brings about improvement of palmoplantar hidrosis. The effect of Shigyaku-san on 40 patients was evaluated based on changes in palmoplantar sweat volume and skin temperature before and after stress loading. We also measured changes in the palmoplantar sweat volume and skin temperature due to stress load in 35 healthy controls who did not receive Shigyaku-san. Before treatment, the pre-stress sweat volume in patients was larger than that in healthy controls, however, after Shigyaku-san treatment, their pre-stress sweat volume decreased. With stress, the sweat volume increased in both patients and controls, but the net increase in the patients was larger than that in healthy controls. After Shigyaku-san treatment, the net increase of sweat volume due to stress was smaller than that of pretreatment, however, it did not show a significant difference with that of healthy controls. The palmoplantar skin temperature of the patients before treatment was lower than that of healthy controls. Palmoplantar skin temperature rose with stress loading in healthy controls, but decreased in pretreatment patients. Shigyaku-san treatment reduced the palmoplantar perspiration in palmoplantar hidrosis patients at rest and under stress. Furthermore, it also improved other serious complications, especially coldness of the extremities.

Potential field studies of the central San Luis Basin and San Juan Mountains, Colorado and New Mexico, and southern and western Afghanistan

Science.gov (United States)

Drenth, Benjamin John

This dissertation includes three separate chapters, each demonstrating the interpretive utility of potential field (gravity and magnetic) geophysical datasets at various scales and in various geologic environments. The locations of these studies are the central San Luis Basin of Colorado and New Mexico, the San Juan Mountains of southwestern Colorado, and southern and western Afghanistan. The San Luis Basin is the northernmost of the major basins that make up the Rio Grande rift, and interpretation of gravity and aeromagnetic data reveals patterns of rifting, rift-sediment thicknesses, distribution of pre-rift volcanic and sedimentary rocks, and distribution of syn-rift volcanic rocks. Syn-rift Santa Fe Group sediments have a maximum thickness of ˜2 km in the Sanchez graben near the eastern margin of the basin along the central Sangre de Cristo fault zone. Under the Costilla Plains, thickness of these sediments is estimated to reach ˜1.3 km. The Santa Fe Group sediments also reach a thickness of nearly 1 km within the Monte Vista graben near the western basin margin along the San Juan Mountains. A narrow, north-south-trending structural high beneath San Pedro Mesa separates the graben from the structural depression beneath the Costilla Plains. Aeromagnetic anomalies are interpreted to mainly reflect variations of remanent magnetic polarity and burial depth of the 5.3-3.7 Ma Servilleta basalt of the Taos Plateau volcanic field. Magnetic-source depth estimates indicate patterns of subsidence following eruption of the basalt and show that the Sanchez graben has been the site of maximum subsidence. One of the largest and most pronounced gravity lows in North America lies over the rugged San Juan Mountains in southwestern Colorado. A buried, low-density silicic batholith related to an Oligocene volcanic field coincident with the San Juan Mountains has been the accepted interpretation of the source of the gravity low since the 1970s. However, this interpretation was

SANS study of the structural evolution in NIPA/SA gel on dehydration

CERN Document Server

Sugiyama, M; Maeda, Y; Hara, K

2002-01-01

Mesoscopic structures of N-isopropylacryl-amide/sodium acrylate (NIPA/SA) gels with several water contents were investigated with a small-angle neutron scattering (SANS) method in order to make clear their structural evolution on dehydration. The evolution of the SANS profile with a decrease in the water content in the gel could be classified into three stages. In the beginning, there was no peak in the SANS profile except for the central part, which steadily intensified. With the further water dissipation, a side peak appeared at around 0.02 A sup - sup 1 , the intensity of which increased up to a certain water content and then decreased. These results indicate that the water dissipation in the NIPA/SA gel occurs inhomogeneously. (orig.)

76 FR 41811 - Kellaway Proposed Low-Effect Habitat Conservation Plan for the Morro Shoulderband Snail, San Luis...

Science.gov (United States)

2011-07-15

...] Kellaway Proposed Low-Effect Habitat Conservation Plan for the Morro Shoulderband Snail, San Luis Obispo... species in the community of Los Osos, San Luis Obispo County, California. The applicants would implement a... Los Osos, San Luis Obispo County, California. The applicants are requesting a permit for take of Morro...

Rare Plants - City of San Diego [ds455

Data.gov (United States)

California Natural Resource Agency — The Biological Monitoring Plan (BMP; Ogden 1996) for the Multiple Species Conservation Program (MSCP) was developed in 1996 and is a component of the City of San...

75 FR 9921 - San Diego County Water Authority Natural Communities Conservation Program/Habitat Conservation...

Science.gov (United States)

2010-03-04

... Diego County Water Authority Natural Communities Conservation Program/Habitat Conservation Plan, San... the NCCP/HCP's conservation strategy. Covered Activities would include developing new water... permit application, and notice of public meetings. SUMMARY: The San Diego County Water Authority (Water...

Damage Detection Response Characteristics of Open Circuit Resonant (SansEC) Sensors

Science.gov (United States)

Dudley, Kenneth L.; Szatkowski, George N.; Smith, Laura J.; Koppen, Sandra V.; Ely, Jay J.; Nguyen, Truong X.; Wang, Chuantong; Ticatch, Larry A.; Mielnik, John J.

2013-01-01

The capability to assess the current or future state of the health of an aircraft to improve safety, availability, and reliability while reducing maintenance costs has been a continuous goal for decades. Many companies, commercial entities, and academic institutions have become interested in Integrated Vehicle Health Management (IVHM) and a growing effort of research into "smart" vehicle sensing systems has emerged. Methods to detect damage to aircraft materials and structures have historically relied on visual inspection during pre-flight or post-flight operations by flight and ground crews. More quantitative non-destructive investigations with various instruments and sensors have traditionally been performed when the aircraft is out of operational service during major scheduled maintenance. Through the use of reliable sensors coupled with data monitoring, data mining, and data analysis techniques, the health state of a vehicle can be detected in-situ. NASA Langley Research Center (LaRC) is developing a composite aircraft skin damage detection method and system based on open circuit SansEC (Sans Electric Connection) sensor technology. Composite materials are increasingly used in modern aircraft for reducing weight, improving fuel efficiency, and enhancing the overall design, performance, and manufacturability of airborne vehicles. Materials such as fiberglass reinforced composites (FRC) and carbon-fiber-reinforced polymers (CFRP) are being used to great advantage in airframes, wings, engine nacelles, turbine blades, fairings, fuselage structures, empennage structures, control surfaces and aircraft skins. SansEC sensor technology is a new technical framework for designing, powering, and interrogating sensors to detect various types of damage in composite materials. The source cause of the in-service damage (lightning strike, impact damage, material fatigue, etc.) to the aircraft composite is not relevant. The sensor will detect damage independent of the cause

San Francisco Bay, California 1 arc-second DEM

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The 1-second San Francisco Bay, California Elevation Grid provides bathymetric data in ASCII raster format of 1-second resolution in geographic coordinates. This...

San Francisco Bay Multi-beam Bathymetry: Area A

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — These multi-beam bathymetric data were collected over shallow subtidal areas in the San Francisco Bay estuary system. Bathymetric and acoustic backscatter data were...

75 FR 17430 - Hopper Mountain, Bitter Creek, and Blue Ridge National Wildlife Refuges, Kern, San Luis Obispo...

Science.gov (United States)

2010-04-06

...] Hopper Mountain, Bitter Creek, and Blue Ridge National Wildlife Refuges, Kern, San Luis Obispo, Tulare... Wildlife Refuges (NWRs) located in Kern, San Luis Obispo, Tulare, and Ventura counties of California. We... developing a CCP for Hopper Mountain, Bitter Creek, and Blue Ridge NWRs in Kern, San Luis Obispo, Tulare, and...

SANS analysis of aqueous ionic perfluoropolyether micelles

CERN Document Server

Gambi, C M C; Chittofrati, A; Pieri, R; Baglioni, P; Teixeira, J

2002-01-01

Preliminary SANS results of ionic chlorine terminated perfluoropolyether micelles in water are given. The experimental spectra have been analyzed by a two-shell ellipsoidal model for the micellar form factor and a screened Coulombic plus hard-sphere repulsion potential for the structure factor. (orig.)

Poziv: Duhovnost i san. San o oružju Franje Asiškoga

OpenAIRE

Balajić, Siniša

2009-01-01

San o oružju Franje Asiškoga doima se važnim elemenatom u proučavanju, ne toliko poziva Franje Asiškoga, koliko poziva uopće. Budući da se analizom i interpretacijom snova bave antropologija, psihologija, filozofija, teologija, itd., koncept razumijevanja ovoga sna uokviruje različita znanstvena (antropologija, psihologija) i teorijska načela (filozofija, teologija-duhovnost). Svjesni smo da proučavanje nečijega života, a pogotovo proučavanje nečijih snova, nije nimalo la...

77 FR 36041 - San Antonio Central Railroad, L.L.C.-Lease Exemption-Port Authority of San Antonio

Science.gov (United States)

2012-06-15

... control of SAC upon SAC becoming a Class III rail carrier. As a result of this transaction, SAC will provide common carrier rail service over the rail lines owned by the Port in the East Kelly Railport (the... and operate approximately four miles of rail line owned by the Port Authority of San Antonio (the Port...

Anthropogenic influences on shoreline and nearshore evolution in the San Francisco Bay coastal system

Science.gov (United States)

Dallas, K.L.; Barnard, P.L.

2011-01-01

Analysis of four historical bathymetric surveys over a 132-year period has revealed significant changes to the morphology of the San Francisco Bar, an ebb-tidal delta at the mouth of San Francisco Bay estuary. From 1873 to 2005 the San Francisco Bar vertically-eroded an average of 80 cm over a 125 km2 area, which equates to a total volume loss of 100 ± 52 million m3 of fine- to coarse-grained sand. Comparison of the surveys indicates the entire ebb-tidal delta contracted radially, with the crest moving landward an average of 1 km. Long-term erosion of the ebb-tidal delta is hypothesized to be due to a reduction in the tidal prism of San Francisco Bay and a decrease in coastal sediment supply, both as a result of anthropogenic activities. Prior research indicates that the tidal prism of the estuary was reduced by 9% from filling, diking, and sedimentation. Compilation of historical records dating back to 1900 reveals that a minimum of 200 million m3 of sediment has been permanently removed from the San Francisco Bay coastal system through dredging, aggregate mining, and borrow pit mining. Of this total, ~54 million m3 of sand-sized or coarser sediment was removed from central San Francisco Bay. With grain sizes comparable to the ebb-tidal delta, and its direct connection to the bay mouth, removal of sediments from central San Francisco Bay may limit the sand supply to the delta and open coast beaches. SWAN wave modeling illustrates that changes to the morphology of the San Francisco Bar have altered the alongshore wave energy distribution at adjacent Ocean Beach, and thus may be a significant factor in a persistent beach erosion ‘hot spot’ occurring in the area. Shoreline change analyses show that the sandy shoreline in the shadow of the ebb-tidal delta experienced long-term (1850s/1890s to 2002) and short-term (1960s/1980s to 2002) accretion while the adjacent sandy shoreline exposed to open-ocean waves experienced long-term and short-term erosion. Therefore

75 FR 11194 - San Diego County Water Authority Natural Communities Conservation Program/Habitat Conservation...

Science.gov (United States)

2010-03-10

... Diego County Water Authority Natural Communities Conservation Program/Habitat Conservation Plan, San... meetings for the San Diego County Water Authority's (Water Authority/Applicant) draft Natural Communities Conservation Plan (NCCP)/Habitat Conservation Plan (HCP) prepared in application to us for an incidental take...

Isotopic Evidence of Nitrate Sources and its Relationship to Algae in the San Joaquin River, California

Science.gov (United States)

Silva, S. R.; Kendall, C.; Young, M. B.; Stringfellow, W. T.; Borglin, S. E.; Kratzer, C. R.; Dahlgren, R. A.; Schmidt, C.; Rollog, M. E.

2007-12-01

Many competing demands have been placed on the San Joaquin River including deep water shipping, use as agricultural and drinking water, transport of agricultural and urban runoff, and recreation. These long-established demands limit the management options and increase the importance of understanding the river dynamics. The relationships among sources of water, nitrate, and algae in the San Joaquin River must be understood before management decisions can be made to optimize aquatic health. Isotopic analyses of water samples collected along the San Joaquin River in 2005-2007 have proven useful in assessing these relationships: sources of nitrate, the productivity of the San Joaquin River, and the relationship between nitrate and algae in the river. The San Joaquin River receives water locally from wetlands and agricultural return flow, and from three relatively large tributaries whose headwaters are in the Sierra Nevada. The lowest nitrate concentrations occur during periods of high flow when the proportion of water from the Sierra Nevada is relatively large, reflecting the effect of dilution from the big tributaries and indicating that a large fraction of the nitrate is of local origin. Nitrogen isotopes of nitrate in the San Joaquin River are relatively high (averaging about 12 per mil), suggesting a significant source from animal waste or sewage and/or the effects of denitrification. The d15N of nitrate varies inversely with concentration, indicating that these high isotopic values are also a local product. The d15N values of nitrate from most of the local tributaries is lower than that in the San Joaquin suggesting that nitrate from these tributaries does not account for a significant fraction of nitrate in the river. The source of the non-tributary nitrate must be either small unmeasured surface inputs or groundwater. To investigate whether groundwater might be a significant source of nitrate to the San Joaquin River, groundwater samples are being collected

Proceedings of the Fourth Social Aspects and Recreation Research Symposium: February 4-6, 2004, San Francisco, California

Science.gov (United States)

Patrick T. Tierney; Deborah J. (Tech. coords.) Chavez

2004-01-01

The Fourth Social Aspects and Recreation Research (SARR) Symposium was held February 4-6, 2004 in San Francisco, California at the Presidio of San Francisco, a component of Golden Gate National Recreation Area and at San Francisco State University. The theme was: Linking People to the Outdoors: Connections for Healthy Lands, People and Communities.

Structure analyses of swollen rubber-carbon black systems by contrast variation SANS

International Nuclear Information System (INIS)

Takenaka, Mikihito; Nishitsuji, Shotaro; Fujii, Sumiaki; Amino, Naoya; Ishikawa, Yasuhiro; Yamaguchi, Daisuke; Koizumi, Satoshi

2010-01-01

The polymer layers adsorbed on carbon black (CB) aggregates in rubber/CB systems have been investigated with contrast variation small-angle neutron scattering (SANS) method. Specimens were swollen by toluene/deuterated toluene solvents having various scattering length densities and their scattering intensities were measured with SANS. The contrast variation SANS for the specimens yielded partial scattering functions: the scattering function for polymer-polymer correlation S pp (q), the scattering function for CB- CB correlation S cc (q), and the scattering function for polymer- CB correlation S pc (q). The analyses of the partial scattering functions explored the existence of dense polymer layers around CB aggregates. Several characteristic parameters are estimated from the analyses, such as the size of aggregates, the thickness of layers, and the volume fractions of polymer of layers and matrix. (author)

Tectonic activity as a significant source of crustal tetrafluoromethane emissions to the atmosphere: observations in groundwaters along the San Andreas Fault

Science.gov (United States)

Deeds, Daniel A.; Kulongoski, Justin T.; Muhle, Jens; Weiss, Ray F.

2015-01-01

Tetrafluoromethane (CF4) concentrations were measured in 14 groundwater samples from the Cuyama Valley, Mil Potrero and Cuddy Valley aquifers along the Big Bend section of the San Andreas Fault System (SAFS) in California to assess whether tectonic activity in this region is a significant source of crustal CF4 to the atmosphere. Dissolved CF4 concentrations in all groundwater samples but one were elevated with respect to estimated recharge concentrations including entrainment of excess air during recharge (CreCre; ∼30 fmol kg−1 H2O), indicating subsurface addition of CF4 to these groundwaters. Groundwaters in the Cuyama Valley contain small CF4 excesses (0.1–9 times CreCre), which may be attributed to an in situ release from weathering and a minor addition of deep crustal CF4 introduced to the shallow groundwater through nearby faults. CF4 excesses in groundwaters within 200 m of the SAFS are larger (10–980 times CreCre) and indicate the presence of a deep crustal flux of CF4 that is likely associated with the physical alteration of silicate minerals in the shear zone of the SAFS. Extrapolating CF4 flux rates observed in this study to the full extent of the SAFS (1300 km × 20–100 km) suggests that the SAFS potentially emits (0.3–1)×10−1 kg(0.3–1)×10−1 kg CF4 yr−1 to the Earth's surface. For comparison, the chemical weathering of ∼7.5×104 km2∼7.5×104 km2 of granitic rock in California is estimated to release (0.019–3.2)×10−1 kg(0.019–3.2)×10−1 kg CF4 yr−1. Tectonic activity is likely an important, and potentially the dominant, driver of natural emissions of CF4 to the atmosphere. Variations in preindustrial atmospheric CF4 as observed in paleo-archives such as ice cores may therefore represent changes in both continental weathering and tectonic activity, including changes driven by variations in continental ice cover during glacial–interglacial transitions.

Radionuclide concentrations in fish collected from Jemez, Nambe, and San Ildefonso Tribal Lakes

International Nuclear Information System (INIS)

Fresquez, P.R.; Armstrong, D.R.; Salazar, J.G.

1995-02-01

Radionuclide concentrations ( 90 Sr, 137 Cs, 238 Pu, 239 Pu,and total uranium) were determined in fish collected from Jemez, Nambe, and San Ildefonso tribal lakes. With the exception of 137 Cs, all other radionuclides were not significantly different in (stocked) rainbow trout collected from Jemez and Nambe as compared with game fish collected from Abiquiu, Heron, and El Vado Reservoirs. Although 137 Cs levels in trout from Jemez (3.2 x 10 -2 pCi per dry gram) and Nambe (7.5 x 10 -2 pCi per dry gram) were significantly higher than 137 Cs concentrations in fish from Abiquiu, Heron, and El Vado, they were still well below the regional statistical (worldwide fallout) reference level (i.e., -2 pCi per dry gram). Game and nongame fish collected from San Ildefonso contained higher and significantly higher concentrations of uranium, respectively, as compared with fish collected from Abiquiu, Heron, and El Vado. The higher uranium concentrations in fish from San Ildefonso as compared with fish from Abiquiu, Heron, and El Vado were attributed to the higher natural soil uranium contents in the area as compared with the geology of the area upstream of San Ildefonso. The effective (radiation) dose equivalent (EDE) from consuming 46 lb of game fish from Jemez, Nambe, and San Ildefonso lakes, after natural background has been subtracted, was 0.013 (±0.002), 0.019 (±0.012), and 0.017 (±0.028) mrem/yr, respectively. Similarly, the EDE from consuming nongame fish from San Ildefonso was 0.0092 (±0.0084) mrem/yr. The highest calculated dose, based on the mean + 2 standard deviation (95% confidence level), was 0.073 mrem/yr; this was <0.08% of the International Commission on Radiological Protection permissible dose limit for protecting members of the public

SANS-polymer and functional materials with neutron in Indonesia. Progress report on the collaboration activities?

International Nuclear Information System (INIS)

Ikram, A.; Gunawan; Sukirman, E.; Ridwan; Jahja, A.K.

2000-01-01

Activities on SANS-polymer collaboration program are reported. This paper presents SANS-data from Sodium Dodecyl Sulphate that have been obtained using BATAN's SANS machine in Serpong. Reports are also presented about activities in the groups for functional materials structural determination which includes magnetic, HTc superconducting and superionic conducting materials. Discussions are also given towards the way the collaboration activities were carried out in the last three years as well as impact of neutron scattering facility conditions in Indonesia. (author)

Hydrology of the middle San Pedro area, southeastern Arizona

Science.gov (United States)

Cordova, Jeffrey T.; Dickinson, Jesse; Beisner, Kimberly R.; Hopkins, Candice B.; Kennedy, Jeffrey R.; Pool, Donald R.; Glenn, Edward P.; Nagler, Pamela L.; Thomas, Blakemore E.

2015-05-05

In the middle San Pedro Watershed in southeastern Arizona, groundwater is the primary source of water supply for municipal, domestic, industrial, and agricultural use. The watershed comprises two smaller subareas, the Benson subarea and the Narrows-Redington subarea. Early 21st century projections for heavy population growth in the watershed have not yet become a reality, but increased groundwater withdrawals could have undesired consequences - such as decreased base flow to the San Pedro River, and groundwater-level declines - that would lead to the need to deepen existing wells. This report describes the hydrology, hydrochemistry, water quality, and development of a groundwater budget for the middle San Pedro Watershed, focusing primarily on the elements of groundwater movement that could be most useful for the development of a groundwater modelPrecipitation data from Tombstone, Arizona, and base flow at the stream-gaging station on the San Pedro River at Charleston both show relatively dry periods during the 1960s through the mid-1980s and in the mid-1990s to 2009, and wetter periods from the mid-1980s through the mid-1990s. Water levels in four out of five wells near the mountain fronts show cyclical patterns of recharge, with rates of recharge greatest in the early 1980s through the mid-1990s. Three wells near the San Pedro River recorded their lowest levels during the 1950s to the mid-1960s. The water-level record from one well, completed in the confined part of the coarse-grained lower basin fill, showed a decline of approximately 21 meters.Annual flow of the San Pedro River, measured at the Charleston and Redington gages, has decreased since the 1940s. The median annual streamflow and base flow at the gaging station on the river near Tombstone has decreased by 50 percent between the periods 1968–1986 and 1997–2009. Estimates of streamflow infiltration along the San Pedro River during 1914–2009 have decreased 44 percent, with the largest decreases in

San Juanico, BCS, Mexico, hybrid electric plant renewable energies in the rural communities development; Planta electrica hibrida San Juanico, B.C.S., Mexico, las energias renovables en el desarrollo de las comunidades rurales

Energy Technology Data Exchange (ETDEWEB)

Lopez Rios, Serafin [Gerencia de Proyectos Geotermoelectricos, Comision Federal de Electricidad (Mexico)

1999-08-01

The hybrid electric plant of San Juanico, B.C.S., Mexico, is described in terms of its environmental goals, operating process and contribution to the development of that rural community of the Baja California Peninsula. San Juanico hybrid electric plant is organized in three electrical generation systems that work in parallel: one uses solar energy, another wind energy and a third one uses diesel fuel. [Spanish] Se describe la planta hibrida de San Juanico, BCS, Mexico, en terminos de los objetivos ambientales que condujeron a su realizacion, asi como de su proceso operativo y de la participacion que tiene en el desarrollo de esa comunidad rural de la peninsula de Baja California, Mexico. La planta hibrida de San Juanico esta constituida por tres sistemas de generacion de electrcicidad que operan en paralelo: uno utiliza energia radiante del sol, otro energia del viento y un tercero utiliza diesel.

78 FR 53113 - Approval and Promulgation of Implementation Plans; California; San Joaquin Valley; Contingency...

Science.gov (United States)

2013-08-28

...] Approval and Promulgation of Implementation Plans; California; San Joaquin Valley; Contingency Measures for... California to address Clean Air Act nonattainment area contingency measure requirements for the 1997 annual... Air Act Requirements for Contingency Measures III. Review of the Submitted San Joaquin Valley PM 2.5...

Response of the Cottonwood Leaf Beetle (Coleoptera: Chrysomelidae) to Bacillus thuringiensis var. san diego

Science.gov (United States)

Leah S. Bauer

1990-01-01

A standardized laboratory bioassay was used to quantify the lethal and sub-lethal responses of larval and adult cottonwood leaf beetles, Chrysomela scripta F., to Bacillus thuringiensis var. san diego, formulated as M-One standard powder (Mycogen Corporation, San Diego). The median lethal concentration (LC

San Diego, California 1/3 arc-second DEM

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The 1/3-second San Diego, California Elevation Grid provides bathymetric data in ASCII raster format of 1/3-second resolution in geographic coordinates. This grid is...

LOD First Estimates In 7406 SLR San Juan Argentina Station

Science.gov (United States)

Pacheco, A.; Podestá, R.; Yin, Z.; Adarvez, S.; Liu, W.; Zhao, L.; Alvis Rojas, H.; Actis, E.; Quinteros, J.; Alacoria, J.

2015-10-01

In this paper we show results derived from satellite observations at the San Juan SLR station of Felix Aguilar Astronomical Observatory (OAFA). The Satellite Laser Ranging (SLR) telescope was installed in early 2006, in accordance with an international cooperation agreement between the San Juan National University (UNSJ) and the Chinese Academy of Sciences (CAS). The SLR has been in successful operation since 2011 using NAOC SLR software for the data processing. This program was designed to calculate satellite orbits and station coordinates, however it was used in this work for the determination of LOD (Length Of Day) time series and Earth Rotation speed.

Merchandising of cigarettes in San Francisco pharmacies: 27 years later.

Science.gov (United States)

Eule, B; Sullivan, M K; Schroeder, S A; Hudmon, K S

2004-12-01

To estimate changes since 1976 in the proportion of San Francisco pharmacies that sell cigarettes and to characterise the advertising of cigarettes and the merchandising of non-prescription nicotine replacement therapy (NRT) products in these retail establishments. 100 randomly selected San Francisco pharmacies were visited in 2003. Pharmacies were characterised based on the sale of cigarettes, advertising for cigarettes, and the merchandising of non-prescription NRT products. In 2003, 61% of pharmacies sold cigarettes, a significant decrease compared to 89% of pharmacies selling cigarettes in 1976 (p merchandise the primary known risk factor for death in the USA.

Approches plurielles du nom sans déterminant distributions, interprétations, fonctions

CERN Document Server

Prescod, Paula

2017-01-01

Réunies sous des perspectives plurielles, les contributions de cet ouvrage fournissent des appréciations diverses des distributions, interprétations et fonctions du nom sans déterminant. La pluralité des outils d'analyse adoptés permet de faire émerger le caractère composite des noms sans déterminant dans diverses langues.

Educational intervention on pregnancy in adolescence. “San Francisco” Consejo Popular. Venezuela

OpenAIRE

Niurka Fleites Santana; Yosmel Álvarez González; Iván Arlé González Duque; Jayce Díaz Díaz

2015-01-01

Background:The studies accomplished in the worldwide space on pregnancy in adolescence demonstrate the need of an integral attention that would help the family in young people's education.Objective: to implement a program of educational intervention that contribute to modify young people's knowledges on pregnancy in adolescence.Methods: Study of educational intervention in teens of San Francisco community, belonging to the Municipality of Agua Blanca, San Francisco clinic, Portuguesa State, d...

Subsurface geometry of the San Andreas fault in southern California: Results from the Salton Seismic Imaging Project (SSIP) and strong ground motion expectations

Science.gov (United States)

Fuis, Gary S.; Bauer, Klaus; Goldman, Mark R.; Ryberg, Trond; Langenheim, Victoria; Scheirer, Daniel S.; Rymer, Michael J.; Stock, Joann M.; Hole, John A.; Catchings, Rufus D.; Graves, Robert; Aagaard, Brad T.

2017-01-01

The San Andreas fault (SAF) is one of the most studied strike‐slip faults in the world; yet its subsurface geometry is still uncertain in most locations. The Salton Seismic Imaging Project (SSIP) was undertaken to image the structure surrounding the SAF and also its subsurface geometry. We present SSIP studies at two locations in the Coachella Valley of the northern Salton trough. On our line 4, a fault‐crossing profile just north of the Salton Sea, sedimentary basin depth reaches 4 km southwest of the SAF. On our line 6, a fault‐crossing profile at the north end of the Coachella Valley, sedimentary basin depth is ∼2–3  km">∼2–3  km and centered on the central, most active trace of the SAF. Subsurface geometry of the SAF and nearby faults along these two lines is determined using a new method of seismic‐reflection imaging, combined with potential‐field studies and earthquakes. Below a 6–9 km depth range, the SAF dips ∼50°–60°">∼50°–60° NE, and above this depth range it dips more steeply. Nearby faults are also imaged in the upper 10 km, many of which dip steeply and project to mapped surface fault traces. These secondary faults may join the SAF at depths below about 10 km to form a flower‐like structure. In Appendix D, we show that rupture on a northeast‐dipping SAF, using a single plane that approximates the two dips seen in our study, produces shaking that differs from shaking calculated for the Great California ShakeOut, for which the southern SAF was modeled as vertical in most places: shorter‐period (TT<1  s) shaking is increased locally by up to a factor of 2 on the hanging wall and is decreased locally by up to a factor of 2 on the footwall, compared to shaking calculated for a vertical fault.

San Joaquin Valley Aerosol Health Effects Research Center (SAHERC)

Data.gov (United States)

Federal Laboratory Consortium — At the San Joaquin Valley Aerosol Health Effects Center, located at the University of California-Davis, researchers will investigate the properties of particles that...

Yi-gan san restores behavioral alterations and a decrease of brain glutathione level in a mouse model of schizophrenia.

Science.gov (United States)

Makinodan, Manabu; Yamauchi, Takahira; Tatsumi, Kouko; Okuda, Hiroaki; Noriyama, Yoshinobu; Sadamatsu, Miyuki; Kishimoto, Toshifumi; Wanaka, Akio

2009-01-01

The traditional Chinese herbal medicine yi-gan san has been used to cure neuropsychological disorders. Schizophrenia can be one of the target diseases of yi-gan san. We aimed at evaluating the possible use of yi-gan san in improving the schizophrenic symptoms of an animal model. Yi-gan san or distilled water was administered to mice born from pregnant mice injected with polyinosinic-polycytidilic acid or phosphate buffered saline. The former is a model of schizophrenia based on the epidemiological data that maternal infection leads to psychotic disorders including schizophrenia in the offspring. Prepulse inhibition and sensitivity to methamphetamine in open field tests were analyzed and the total glutathione content of whole brains was measured. Yi-gan san reversed the decrease in prepulse inhibition, hypersensitivity to methamphetamine and cognitive deficits found in the model mice to the level of control mice. Total glutathione content in whole brains was reduced in the model mice but was restored to normal levels by yi-gan san treatment. These results suggest that yi-gan san may have ameliorating effects on the pathological symptoms of schizophrenia.

33 CFR 165.1141 - Safety Zone; San Clemente 3 NM Safety Zone, San Clemente Island, CA.

Science.gov (United States)

2010-07-01

...) Location. The following area is a safety zone: All waters of the Pacific Ocean surrounding San Clemente Island, from surface to bottom, extending from the high tide line on the island seaward 3 NM. The zone... 3 NM from the high tide line to 33°02.82′ N, 118°30.65′ W; thence 33°01.29′ N, 118°33.88′ W; thence...

People's Front in Defence of Land, San Salvador Atenco: A testimony

OpenAIRE

Martha Pérez Pineda

2011-01-01

Martha Pérez Pineda gives her statement of the Peoples Front in Defence of the Land (The Peoples Front in Defence of Land (Frente del Pueblo en Defensa de la Tierra, FPDT) was formed in 2002, by residents of San Salvador Atenco, to resist their forced displacement by the federal government of Mexico and Estado de Mexico. The government planned to displace them to make way for the new Mexico City Airport. The people of San Salvador Atenco refused and battled, the most common fights were disput...

San Lorenzo and the Poggendorff Illusion in Ravenna

Directory of Open Access Journals (Sweden)

Olga Daneyko

2011-06-01

Full Text Available In the Mausoleum of Galla Placidia (Ravenna, Italy, the San Lorenzo lunette shows two peculiar visual effects: a transparency effect of gold seen through gold and perceptual collinearity between two parts of a cross which are physically misaligned. Both effects are found within the area of the halo surrounding the saint's head. In this work we addressed the problem posed by the physical misalignment of the cross. Our hypothesis is that the physical misalignment went unnoticed throughout history because the artist produced a perceptual alignment to correct for the Poggendorff illusion. Hence, we asked observers to align two ends of a cross in a reproduction showing the silhouette of San Lorenzo's torso holding the cross. Results support our hypothesis: both direction and magnitude of adjustments comply with the alignment in the original mosaic.

Direct interaction of the Usher syndrome 1G protein SANS and myomegalin in the retina.

Science.gov (United States)

Overlack, Nora; Kilic, Dilek; Bauss, Katharina; Märker, Tina; Kremer, Hannie; van Wijk, Erwin; Wolfrum, Uwe

2011-10-01

The human Usher syndrome (USH) is the most frequent cause of combined hereditary deaf-blindness. USH is genetically heterogeneous with at least 11 chromosomal loci assigned to 3 clinical types, USH1-3. We have previously demonstrated that all USH1 and 2 proteins in the eye and the inner ear are organized into protein networks by scaffold proteins. This has contributed essentially to our current understanding of the function of USH proteins and explains why defects in proteins of different families cause very similar phenotypes. We have previously shown that the USH1G protein SANS (scaffold protein containing ankyrin repeats and SAM domain) contributes to the periciliary protein network in retinal photoreceptor cells. This study aimed to further elucidate the role of SANS by identifying novel interaction partners. In yeast two-hybrid screens of retinal cDNA libraries we identified 30 novel putative interacting proteins binding to the central domain of SANS (CENT). We confirmed the direct binding of the phosphodiesterase 4D interacting protein (PDE4DIP), a Golgi associated protein synonymously named myomegalin, to the CENT domain of SANS by independent assays. Correlative immunohistochemical and electron microscopic analyses showed a co-localization of SANS and myomegalin in mammalian photoreceptor cells in close association with microtubules. Based on the present results we propose a role of the SANS-myomegalin complex in microtubule-dependent inner segment cargo transport towards the ciliary base of photoreceptor cells. Copyright © 2011 Elsevier B.V. All rights reserved.

33 CFR 165.1121 - Security Zone: Fleet Supply Center Industrial Pier, San Diego, CA.

Science.gov (United States)

2010-07-01

... Guard District § 165.1121 Security Zone: Fleet Supply Center Industrial Pier, San Diego, CA. (a... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone: Fleet Supply Center Industrial Pier, San Diego, CA. 165.1121 Section 165.1121 Navigation and Navigable Waters COAST...

76 FR 4371 - Notice of Intent to Prepare an Environmental Impact Statement for the Proposed San Juan Basin...

Science.gov (United States)

2011-01-25

...; NMNM122352] Notice of Intent to Prepare an Environmental Impact Statement for the Proposed San Juan Basin Energy Connect Project, San Juan County, New Mexico, and La Plata County, Colorado AGENCY: Bureau of Land... prepare an Environmental Impact Statement (EIS) on the proposed San Juan Energy Connect Project, and by...

78 FR 73557 - Guadalupe-Nipomo Dunes National Wildlife Refuge, San Luis Obispo County, CA: Intent To Prepare a...

Science.gov (United States)

2013-12-06

...-FF08R00000] Guadalupe-Nipomo Dunes National Wildlife Refuge, San Luis Obispo County, CA: Intent To Prepare a...) for the Guadalupe-Nipomo Dunes National Wildlife Refuge located in San Luis Obispo County of... (Refuge) in San Luis Obispo County, California. This notice complies with our CCP policy to (1) advise...

San Sebastiani festivali varjutasid hiljutised terroriaktid / Aare Ermel

Index Scriptorium Estoniae

Ermel, Aare, 1957-2013

2001-01-01

San Sebastiani rahvusvahelisel filmifestivalil sai Suure Kuldse merikarbi tšiillase Orlando Lubberti film "Takso kolmele". Parima režissööri auhinna pälvis Jean-Pierre Ameris realistliku draamaga "C'est la vie". Ka teistest auhinnatutest

Character and Implications of a Newly Identified Creeping Strand of the San Andreas fault NE of Salton Sea, Southern California

Science.gov (United States)

Janecke, S. U.; Markowski, D.

2015-12-01

The overdue earthquake on the Coachella section, San Andreas fault (SAF), the model ShakeOut earthquake, and the conflict between cross-fault models involving the Extra fault array and mapped shortening in the Durmid Hill area motivate new analyses at the southern SAF tip. Geologic mapping, LiDAR, seismic reflection, magnetic and gravity datasets, and aerial photography confirm the existence of the East Shoreline strand (ESS) of the SAF southwest of the main trace of the SAF. We mapped the 15 km long ESS, in a band northeast side of the Salton Sea. Other data suggest that the ESS continues N to the latitude of the Mecca Hills, and is >35 km long. The ESS cuts and folds upper Holocene beds and appears to creep, based on discovery of large NW-striking cracks in modern beach deposits. The two traces of the SAF are parallel and ~0.5 to ~2.5 km apart. Groups of east, SE, and ENE-striking strike-slip cross-faults connect the master dextral faults of the SAF. There are few sinistral-normal faults that could be part of the Extra fault array. The 1-km wide ESS contains short, discontinuous traces of NW-striking dextral-oblique faults. These en-echelon faults bound steeply dipping Pleistocene beds, cut out section, parallel tight NW-trending folds, and produced growth folds. Beds commonly dip toward the ESS on both sides, in accord with persistent NE-SW shortening across the ESS. The dispersed fault-fold structural style of the ESS is due to decollements in faulted mud-rich Pliocene to Holocene sediment and ramps and flats along the strike-slip faults. A sheared ladder-like geometric model of the two master dextral strands of the SAF and their intervening cross-faults, best explains the field relationships and geophysical datasets. Contraction across >40 km2 of the southernmost SAF zone in the Durmid Hills suggest that interaction of active structures in the SAF zone may inhibit the nucleation of large earthquakes in this region. The ESS may cross the northern Coachella

Cultural conflicts, dilemmas and disillusionment among the San communities at Platfontein

Directory of Open Access Journals (Sweden)

G.T. Batha

2014-12-01

Full Text Available This article examines the cultural conflicts, dilemmas and disillusionment among the San communities at Platfontein in the Northern Cape province of South Africa. A critical review of written texts, interviews, observations and focus group discussions with the community knowledge-holders shows that the community’s new Westernised lifestyle in the midst of the capitalist society at Platfontein turns the collective spirit, human relations, mutual reverence, sincerity and self-confidence that existed before their contact with Westernised societies into unusual selfishness, individualism, impiety, dishonesty, greed and disregard for others. The conflict between the communal hunter-gatherer culture and the alien individualist mode of existence has created serious dilemmas and moral conflicts in the community. The Westernised mode of existence has alienated the community from their human nature, their natural environment, their productive chores and their communal life. The community has an undefined, unclear and controversial understanding of their own racial identity. The San refer to the black and white races that have historical relationships with them as Others, which in turn has an Othering effect on the San themselves. The causes of moral and psychological conflicts, identity crises, dilemmas and disillusionment are power relations related to ethnic and racial politics, colonial discourse and identity politics. The researcher recommends that to achieve harmonious relationships with other communities and among themselves, the San need to redefine themselves and other societies that have historical ties with them.

Geología y aspectos geográficos de la isla de san andrés, colombia

OpenAIRE

Vargas Cuervo, German

2012-01-01

La Isla de San Andrés ha sido definida geológicamente por varios autores en dos unidades calcáreas de características bien marcadas: Una unidad de calizas heterogéneas,denominada como Formación San Andrés de edad Mioceno y una unidad de calizas coralinas de edad Pleistoceno, conocida como Formación San Luis. La primera unidad aflora en la parte central de la isla y representa la zona de colinas suaves con alturas máximas de 87 m.s.n.m y la Formación San Luis constituye la región plana a suave...

User-friendly software for SANS data reduction and analysis

International Nuclear Information System (INIS)

Biemann, P.; Haese-Seiller, M.; Staron, P.

1999-01-01

At the Geesthacht Neutron Facility (GeNF) a new software is being developed for the reduction of two-dimensional small-angle neutron scattering (SANS) data. The main motivation for this work was to created software for users of our SANS facilities that is easy to use. Another motivation was to provide users with software they can also use at their home institute. Therefore, the software is implemented on a personal computer running WINDOWS. The program reads raw data from an area detector in binary or ascii format and produces ascii files containing the scattering curve. The cross section can be averaged over the whole area of the detector or over users defined sectors only. Scripts can be created for processing large numbers of files. (author)

Examining and Comparing Earthquake Readiness in East San Francisco Bay Area Communities (Invited)

Science.gov (United States)

Ramirez, N.; Bul, V.; Chavez, A.; Chin, W.; Cuff, K. E.; Girton, C.; Haynes, D.; Kelly, G.; Leon, G.; Ramirez, J.; Ramirez, R.; Rodriquez, F.; Ruiz, D.; Torres, J.

2009-12-01

Based on past experiences, the potential for casualties and mass destruction that can result from a high magnitude earthquake are well known. Nevertheless, given the East San Francisco Bay Area’s proximity to the Hayward and San Andreas faults, learning about earthquakes and disaster preparedness is of particular importance. While basic educational programs and materials are available both through emergency relief agencies and schools, little research has been done on their effectiveness. Because of the wide socioeconomic spread between communities in the East Bay, we decided to investigate understandings of issues related to disaster and earthquake preparedness among local populations based upon average household income. To accomplish this, we created a survey that was later uploaded to and implemented using Palm Treo Smart Phones. Survey locations were selected in such a way that they reflected the understandings of residents in a diverse set of socio-economic settings. Thus, these locations included a grocery store and nearby plaza in the Fruitvale district of Oakland, CA (zip=94601; median household income= 33,152), as well as the nearby town of Alameda, CA (zip=94502, median household income= 87,855). Preliminary results suggest that in terms of the objective questions on the survey, people from Alameda who participated in our study performed significantly better (difference in percentage correct greater than 10%) than the people from Fruitvale on two of the advanced earthquake knowledge questions. Interestingly enough, people in Fruitvale significantly outperformed people in Alameda on two of the basic earthquake knowledge questions. The final important finding was that while houses in Alameda tended to be newer and more often retrofitted than houses in Fruitvale, the people of the latter location tended to have a higher percentage of respondents claim confidence in the ability of their house to withstand a major earthquake. Based on preliminary results we

Distribution and abundance of Least Bell’s Vireos (Vireo bellii pusillus) and Southwestern Willow Flycatchers (Empidonax traillii extimus) on the Middle San Luis Rey River, San Diego County, southern California—2017 data summary

Science.gov (United States)

Allen, Lisa D.; Howell, Scarlett L.; Kus, Barbara E.

2018-04-20

We surveyed for Least Bell’s Vireos (LBVI) (Vireo bellii pusillus) and Southwestern Willow Flycatchers (SWFL) (Empidonax traillii extimus) along the San Luis Rey River, between College Boulevard in Oceanside and Interstate 15 in Fallbrook, California (middle San Luis Rey River), in 2017. Surveys were conducted from April 13 to July 11 (LBVI) and from May 16 to July 28 (SWFL). We found 146 LBVI territories, at least 107 of which were occupied by pairs. Five additional transient LBVIs were detected. LBVIs used five different habitat types in the survey area: mixed willow, willow-cottonwood, willow-sycamore, riparian scrub, and upland scrub. Forty-four percent of the LBVIs occurred in habitat characterized as mixed willow and 89 percent of the LBVI territories occurred in areas with greater than 50 percent native plant cover. Of 16 banded LBVIs detected in the survey area, 8 had been given full color-band combinations prior to 2017. Four other LBVIs with single (natal) federal bands were recaptured and banded in 2017. Three LBVIs with single dark blue federal bands indicating that they were banded as nestlings on the lower San Luis Rey River and one LBVI with a single gold federal band indicating that it was banded as a nestling on Marine Corps Base Camp Pendleton (MCBCP) could not be recaptured for identification. One banded LBVI emigrated from the middle San Luis Rey River to the lower San Luis Rey River in 2017.One resident SWFL territory and one transient Willow Flycatcher of unknown subspecies (WIFL) were observed in the survey area in 2017. The resident SWFL territory, which was comprised of mixed willow habitat (5–50 percent native plant cover), was occupied by a single male from May 22 to June 21, 2017. No evidence of pairing or nesting activity was observed. The SWFL male was banded with a full color-combination indicating that he was originally banded as a nestling on the middle San Luis Rey River in 2014 and successfully bred in the survey area in 2016

El patrimonio identitario de la comunidad de San Andrés

Directory of Open Access Journals (Sweden)

Carlos Córdova Martínez

2006-01-01

Full Text Available La identidad y el patrimonio son elementos recurrentes si se quiere defender la cultura frente a un mundo globalizado. Dicha labor debe realizarse de lo local a lo nacional y viceversa. El trabajo aborda el patrimonio de una pequeña comunidad holguinera, el Consejo Popular de San Andrés, cuyo centro es el poblado homónimo. Con un largo devenir histórico, que se remonta a fines del siglo XVI. San Andrés atesora un rico patrimonio, que puede incluirse fundamentalmente dentro de la cultura campesina.

Virgen de la Misericordia, San Jerónimo y San Miguel: el origen del corporativismo sedero en la Valencia bajomedieval (1465-1518.

Directory of Open Access Journals (Sweden)

Juan Martínez Vinat

2017-06-01

Full Text Available El presente estudio indaga sobre el origen del asociacionismo sedero valenciano a través de las tres principales corporaciones fundadas en Valencia a finales de la Edad Media: la cofradía de la Misericordia de veleros de seda, la cofradía de San Jerónimo del Art de Velluters y la cofradía de tintoreros de seda de San Miguel. El análisis de sus ordenanzas confraternales y gremiales, contrastado con otras fuentes documentales de tipo contable (Llibres de Dates e Rebudes, nos permiten conocer la realidad, funcionamiento y desarrollo de tres entidades que protagonizaron el arranque de la sedería valenciana, tanto desde la perspectiva laboral como desde la óptica benéfico-asistencial, ambas inseparables en el periodo que nos ocupa.

"3D_Fault_Offsets," a Matlab Code to Automatically Measure Lateral and Vertical Fault Offsets in Topographic Data: Application to San Andreas, Owens Valley, and Hope Faults

Science.gov (United States)

Stewart, N.; Gaudemer, Y.; Manighetti, I.; Serreau, L.; Vincendeau, A.; Dominguez, S.; Mattéo, L.; Malavieille, J.

2018-01-01

Measuring fault offsets preserved at the ground surface is of primary importance to recover earthquake and long-term slip distributions and understand fault mechanics. The recent explosion of high-resolution topographic data, such as Lidar and photogrammetric digital elevation models, offers an unprecedented opportunity to measure dense collections of fault offsets. We have developed a new Matlab code, 3D_Fault_Offsets, to automate these measurements. In topographic data, 3D_Fault_Offsets mathematically identifies and represents nine of the most prominent geometric characteristics of common sublinear markers along faults (especially strike slip) in 3-D, such as the streambed (minimum elevation), top, free face and base of channel banks or scarps (minimum Laplacian, maximum gradient, and maximum Laplacian), and ridges (maximum elevation). By calculating best fit lines through the nine point clouds on either side of the fault, the code computes the lateral and vertical offsets between the piercing points of these lines onto the fault plane, providing nine lateral and nine vertical offset measures per marker. Through a Monte Carlo approach, the code calculates the total uncertainty on each offset. It then provides tools to statistically analyze the dense collection of measures and to reconstruct the prefaulted marker geometry in the horizontal and vertical planes. We applied 3D_Fault_Offsets to remeasure previously published offsets across 88 markers on the San Andreas, Owens Valley, and Hope faults. We obtained 5,454 lateral and vertical offset measures. These automatic measures compare well to prior ones, field and remote, while their rich record provides new insights on the preservation of fault displacements in the morphology.

Vegetation Mapping - Tecolote Canyon, San Diego Co. [ds656

Data.gov (United States)

California Natural Resource Agency — Vegetation mapping has been conducted at various City of San Diego Park and Recreation Open Space lands in support of natural resource management objectives and the...

Baseline Surveys - Tecolote Canyon, San Diego Co. [ds655

Data.gov (United States)

California Natural Resource Agency — Various resource projects have been conducted in the City of San Diego's Open Space Parks as part of the implementation of the City's Multiple Species Conservation...

San Francisco, California Tsunami Forecast Grids for MOST Model

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The San Francisco, California Forecast Model Grids provides bathymetric data strictly for tsunami inundation modeling with the Method of Splitting Tsunami (MOST)...

A basin-scale approach for assessing water resources in a semiarid environment: San Diego region, California and Mexico

Directory of Open Access Journals (Sweden)

L. E. Flint

2012-10-01

Full Text Available Many basins throughout the world have sparse hydrologic and geologic data, but have increasing demands for water and a commensurate need for integrated understanding of surface and groundwater resources. This paper demonstrates a methodology for using a distributed parameter water-balance model, gaged surface-water flow, and a reconnaissance-level groundwater flow model to develop a first-order water balance. Flow amounts are rounded to the nearest 5 million cubic meters per year.

The San Diego River basin is 1 of 5 major drainage basins that drain to the San Diego coastal plain, the source of public water supply for the San Diego area. The distributed parameter water-balance model (Basin Characterization Model was run at a monthly timestep for 1940–2009 to determine a median annual total water inflow of 120 million cubic meters per year for the San Diego region. The model was also run specifically for the San Diego River basin for 1982–2009 to provide constraints to model calibration and to evaluate the proportion of inflow that becomes groundwater discharge, resulting in a median annual total water inflow of 50 million cubic meters per year. On the basis of flow records for the San Diego River at Fashion Valley (US Geological Survey gaging station 11023000, when corrected for upper basin reservoir storage and imported water, the total is 30 million cubic meters per year. The difference between these two flow quantities defines the annual groundwater outflow from the San Diego River basin at 20 million cubic meters per year. These three flow components constitute a first-order water budget estimate for the San Diego River basin. The ratio of surface-water outflow and groundwater outflow to total water inflow are 0.6 and 0.4, respectively. Using total water inflow determined using the Basin Characterization Model for the entire San Diego region and the 0.4 partitioning factor, groundwater outflow from the San Diego region, through

Recent research on the hydrodynamics of the Sacramento - San Joaquin River Delta and north San Francisco Bay

Science.gov (United States)

Burau, J.R.; Monismith, S.G.; Stacey, M.T.; Oltmann, R.N.; Lacy, J.R.; Schoellhamer, D.H.

1999-01-01

This article presents an overview of recent findings from hydrodynamic research on circulation and mixing in the Sacramento-San Joaquin Delta (Delta) (Figure 1) and North San Francisco Bay (North Bay) (Figure 2). For the purposes of this article, North Bay includes San Pablo Bay, Carquinez Strait, and Suisun Bay. The findings presented are those gained from field studies carried out by the U.S. Geological Survey (USGS), as part of the Interagency Ecological Program (IEP), and Stanford University beginning about 1993. The premise behind these studies was that a basic understanding of circulation and mixing patterns in the Bay and Delta is an essential part of understanding how biota and water quality are affected by natural hydrologic variability, water appropriation, and development activities. Data collected for the field studies described in this article have significantly improved our understanding of Bay and Delta hydrodynamics. Measured flows ,in the Delta have provided valuable information on how water moves through the Delta's network of channels and how export pumping affects flows. Studies of the shallows and shallow-channel exchange processes conducted in Honker Bay have shown that the water residence time in Honker Bay is much shorter than previously reported (on the order of hours to several tidal cycles instead ofweeks). Suisun Bay studies have provided data on hydrodynamic transport and accumulation mechanisms that operate primarily in the channels. The Suisun Bay studies have caused us to revise our understanding of residual circulation in the channels of North Bay and of "entrapment" mechanisms in the low salinity zone. Finally, detailed tidal and residual (tidally averaged) time-scale studies of the mechanisms that control gravitational circulation in the estuary show that density-driven transport in the channels is governed by turbulence time-scale (seconds) interactions between the mean flow and stratification. The hydrodynamic research

Aerial radiological survey of the San Onofre Nuclear Generating Station and surrounding area, San Clemente, California

International Nuclear Information System (INIS)

Hilton, L.K.

1980-12-01

An airborne radiological survey of an 11 km 2 area surrounding the San Onofre Nuclear Generating Station was made 9 to 17 January 1980. Count rates observed at 60 m altitude were converted to exposure rates at 1 m above the ground and are presented in the form of an isopleth map. Detected radioisotopes and their associated gamma ray exposure rates were consistent with that expected from normal background emitters, except directly over the plant

Yi-Gan San Restores Behavioral Alterations and a Decrease of Brain Glutathione Level in a Mouse Model of Schizophrenia

Directory of Open Access Journals (Sweden)

Manabu Makinodan M.D.

2009-01-01

Full Text Available The traditional Chinese herbal medicine yi-gan san has been used to cure neuropsychological disorders. Schizophrenia can be one of the target diseases of yi-gan san. We aimed at evaluating the possible use of yi-gan san in improving the schizophrenic symptoms of an animal model. Yi-gan san or distilled water was administered to mice born from pregnant mice injected with polyinosinic-polycytidilic acid or phosphate buffered saline. The former is a model of schizophrenia based on the epidemiological data that maternal infection leads to psychotic disorders including schizophrenia in the offspring. Prepulse inhibition and sensitivity to methamphetamine in open field tests were analyzed and the total glutathione content of whole brains was measured. Yi-gan san reversed the decrease in prepulse inhibition, hypersensitivity to methamphetamine and cognitive deficits found in the model mice to the level of control mice. Total glutathione content in whole brains was reduced in the model mice but was restored to normal levels by yi-gan san treatment. These results suggest that yi-gan san may have ameliorating effects on the pathological symptoms of schizophrenia.

San Francisco Bay Interferometric Side Scan Imagery: Area A

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Backscatter imagery data were collected over shallow subtidal areas in the San Francisco Bay estuary system. Bathymetric and acoustic backscatter data were collected...

Protección contra inundaciones en zonas urbanas: Caso de la urbanización San Diego distrito de San Martín de Porres-Lima

OpenAIRE

Orosco Benites, Juan Carlos Felipe; Orosco Benites, Juan Carlos Felipe

2004-01-01

El presente trabajo de investigación, trate de explicar en forma didáctica los conocimientos necesarios para poder hacer un análisis y diseño de una protección contra inundaciones en zonas urbanas. En este caso se tomará como ejemplo la urbanización San Diego, en el distrito de San Martín de Porres, el cual periódicamente sufre graves peligros en los meses de enero a marzo por las crecidas del río Chillón. Por tal motivo, se buscó darle una solución técnica a este problema, por...

United States Air Force Personalized Medicine and Advanced Diagnostics Program Panel: Representative Research at the San Antonio Military Medical Center

Science.gov (United States)

2016-05-20

health system. dedicated to excellence in global care PROCESSING OF PROFESSIONAL MEDICAL RESEARCH PUBLICATIONS/PRESENTATIONS INSTRUCTIONS 1. The...present this research at the University of Texas at San Antonio/SAMHS & Universities Research Forum, SURF 2016 in San Antonio, TX, on 20 May 2016. The...at San Antonio/SAMHS & Universities Research Forum, SURF 2016 in San Antonio, TX, on 20 May 2016. 3. LAWS AND REGULATIONS: DoD 5500.07-R, Joint

San Jacinto River oil spill: wetland bioremediation project

International Nuclear Information System (INIS)

Mills, M.A.; Bonner, J.S.

1996-01-01

Gasoline, diesel and unrefined Arabian light crude oil were accidentally released into the San Jacinto River after a series of pipelines ruptured. Natural removal processes (volatilization, dissolution, weathering), fire, and the spill clean-up effort, removed approximately 95% of the petroleum. The area where residual oil was found was an estuarine wetland on the lower San Jacinto River. Samples were collected from 21 study areas and an evaluation of the varying levels of bioremediation was conducted. Phase one has been completed and involved the evaluation of the natural recovery of oil from the spill. Phase two was still in progress and involved the addition of inorganic nutrients and the alternate electron acceptor to enhance the biodegradation of the petroleum. Results showed that biodegradation was responsible for much of the reduction of certain components in petroleum within the first 150 days. 12 refs., 8 figs

San José - El Barrial (Valle Calchaquí, Salta: enfoque biodemográfico

Directory of Open Access Journals (Sweden)

Albeza, María V.

2003-01-01

Full Text Available San José y El Barrial (Departamento de Cachi, Salta pertenecen a la extensa área de los Valles Calchaquíes de la región NOA. Pese a estar separadas por una distancia de 500 metros, sus pobladores se identifican taxativamente en una de ellas. Se realizó una aproximación demográfico-genética a fin de evaluar el accionar de factores evolutivos direccionales (selección natural y flujo génico y estocásticos (deriva génica además de una descripción de la estructura poblacional de dichas localidades. Se entrevistó a la totalidad de los individuos que se encontraban presentes en el momento de la recolección de los datos. San José (N = 154 es una población joven, en tanto que en El Barrial (N = 66 la población mayor de 65 años (14.52 % supera ampliamente el valor estándar de las Naciones Unidas. Estos valores coinciden con la baja Relación Niños-Mujeres y escaso número de individuos entre 0-4 años registrados en El Barrial en contraposición con San José. Ambas poblaciones presentan una alta probabilidad de fijación por deriva medida a través del Coeficiento de Aislamiento Reproductivo y el de Endogamia. La tasa de migración efectiva es menor en San José (0.12 que en El Barrial (0.34. El mayor Indice de Oportunidad para la Selección fue registrado en El Barrial (I = 0.58. If / ps es 0.081 para San José y 0.389 para El Barrial, representando el 32.4 % y el 67.07 % respectivamente por lo que en San José la mayor oportunidad para la selección se estaría ejerciendo a través de la componente de mortalidad y en El Barrial de la de fecundidad.

San Fernando: ¿utopía o proyecto inconcluso?

Directory of Open Access Journals (Sweden)

Juan Pablo Murillo

2008-06-01

Full Text Available El estudio analiza los distintos proyectos de modernización ocurridos en la Facultad de Medicina de San Fernando, en el contexto de una seria crisis institucional a finales del siglo XX. Para ello, a partir de las categorías de colectivo de pensamiento y estilo de pensamiento propuestos por Ludwick Fleck, se hace un estudio de los procesos socio-históricos relacionados con los distintas iniciativas desplegadas en la más antigua escuela de medicina del Perú. Un análisis de las diferentes iniciativas identificadas nos llevan a la hipótesis de que la crisis de San Fernando, como colectivo académico, se basa en las contradicciones propias de un proyecto institucional inconcluso, que además cíclicamente se manifiesta asincrónico y disfuncional, al complejo y cambiante entorno institucional y cultural de la sociedad peruana. El estudio sistematiza las principales características de los diferentes proyectos de modernización institucional. Luego de un análisis del actual contexto del sector salud peruano, a partir de los procesos identificados, se propone una agenda de desarrollo, orientada a generar un ciclo de acumulación y crecimiento académico, que constituya una etapa de transición de cara a los retos que el siglo XXI plantea a los miembros del colectivo San Fernandino.

Examining Dimethyl Sulfide Emissions in California's San Joaquin Valley

Science.gov (United States)

Huber, D.; Hughes, S.; Blake, D. R.

2017-12-01

Dimethyl Sulfide (DMS) is a sulfur-containing compound that leads to the formation of aerosols which can lead to the formation of haze and fog. Whole air samples were collected on board the NASA C-23 Sherpa aircraft during the 2017 Student Airborne Research Program (SARP) over dairies and agricultural fields in the San Joaquin Valley. Analysis of the samples indicate average DMS concentrations of 23 ± 9 pptv, with a maximum concentration of 49 pptv. When compared with DMS concentrations from previous SARP missions (2009-2016), 2017 by far had the highest frequency of elevated DMS in this region. For this study, agricultural productivity of this region was analyzed to determine whether land use could be contributing to the elevated DMS. Top down and bottom up analysis of agriculture and dairies were used to determine emission rates of DMS in the San Joaquin Valley. Correlations to methane and ethanol were used to determine that DMS emissions were strongly linked to dairies, and resulted in R2 values of 0.61 and 0.43, respectively. These values indicate a strong correlation between dairies and DMS emissions. Combined with NOAA HySPLIT back trajectory data and analysis of ground air samples, results suggest that the contribution of dairies to annual DMS emissions in the San Joaquin Valley exceeds those from corn and alfalfa production.

Una lucha a "cielo abierto" : el caso del Frente Amplio Opositor a Minera San Xavier

OpenAIRE

Lamberti, María Julieta

2010-01-01

Se presenta un estudio de caso de un conflicto ecológico distributivo por la instalación de una empresa minera de tajo a cielo abierto desde la perspectiva de uno de los actores involucrados, el Frente Amplio Opositor a Minera San Xavier en Cerro de San Pedro, San Luis Potosí. Para dar cuenta del sentido que le otorgan los miembros del FAO a la instalación de la empresa en la comunidad se utilizan los procesos de enmarcado como herramienta de interpretación. I. La interpretación de los con...

Crustal-scale tilting of the central Salton block, southern California

Science.gov (United States)

Dorsey, Rebecca; Langenheim, Victoria

2015-01-01

The southern San Andreas fault system (California, USA) provides an excellent natural laboratory for studying the controls on vertical crustal motions related to strike-slip deformation. Here we present geologic, geomorphic, and gravity data that provide evidence for active northeastward tilting of the Santa Rosa Mountains and southern Coachella Valley about a horizontal axis oriented parallel to the San Jacinto and San Andreas faults. The Santa Rosa fault, a strand of the San Jacinto fault zone, is a large southwest-dipping normal fault on the west flank of the Santa Rosa Mountains that displays well-developed triangular facets, narrow footwall canyons, and steep hanging-wall alluvial fans. Geologic and geomorphic data reveal ongoing footwall uplift in the southern Santa Rosa Mountains, and gravity data suggest total vertical separation of ∼5.0–6.5 km from the range crest to the base of the Clark Valley basin. The northeast side of the Santa Rosa Mountains has a gentler topographic gradient, large alluvial fans, no major active faults, and tilted inactive late Pleistocene fan surfaces that are deeply incised by modern upper fan channels. Sediments beneath the Coachella Valley thicken gradually northeast to a depth of ∼4–5 km at an abrupt boundary at the San Andreas fault. These features all record crustal-scale tilting to the northeast that likely started when the San Jacinto fault zone initiated ca. 1.2 Ma. Tilting appears to be driven by oblique shortening and loading across a northeast-dipping southern San Andreas fault, consistent with the results of a recent boundary-element modeling study.

Illegal drug use and its correlates in San Juan, Puerto Rico.

Science.gov (United States)

Caetano, Raul; Vaeth, Patrice A C; Canino, Glorisa

2018-04-01

Data on the prevalence and correlates of illegal drug use in Puerto Rico are now almost 20 years old. This study sought to estimate the 12-month prevalence of illegal and non-prescribed medical drug use in San Juan, Puerto Rico and identify sociodemographic correlates of use. Data are from a random household sample of 1510 individuals, 18-64 years of age in San Juan, Puerto Rico. The 12-month prevalence of any illegal or non-prescribed drug use was 16.5%. Prevalence among men (20.7%) was higher than among women (12.9%; chi 2  = 16.308; df = 1; p  .05) were negatively associated with drug use compared to annual income up to $10,000. As in many other places in the U.S., drug use in San Juan, Puerto Rico is high, affecting about 1 in 6 adults in the population. The highest prevalence is for marijuana use, which cannot be medically prescribed and of which recreational use is illegal on the island. Copyright © 2018 Elsevier B.V. All rights reserved.

for presence of hookworms (Uncinaria spp. on San Miguel Island, California

Directory of Open Access Journals (Sweden)

Lyons E. T.

2016-06-01

Full Text Available Necropsy and extensive parasitological examination of dead northern elephant seal (NES pups was done on San Miguel Island, California, in February, 2015. The main interest in the current study was to determine if hookworms were present in NESs on San Miguel Island where two hookworm species of the genus Uncinaria are known to be present - Uncinaria lyonsi in California sea lions and Uncinaria lucasi in northern fur seals. Hookworms were not detected in any of the NESs examined: stomachs or intestines of 16 pups, blubber of 13 pups and blubber of one bull. The results obtained in the present study of NESs on San Miguel Island plus similar finding on Año Nuevo State Reserve and The Marine Mammal Center provide strong indication that NES are not appropriate hosts for Uncinaria spp. Hookworm free-living third stage larvae, developed from eggs of California sea lions and northern fur seals, were recovered from sand. It seems that at this time, further search for hookworms in NESs would be nonproductive.

Auckland--New Zealand's Los Angeles or San Francisco?

Science.gov (United States)

Bogunovich, Dushko

1995-01-01

Compares Auckland (New Zealand) with San Francisco (California) in terms of topographical structure, geographic location, and urban development. Both cities contain striking similarities. Maintains that Auckland can become a world-class city renowned for its beauty if developers and government work in tandem. (MJP)

Mining geologic study in black san stones in Aguas Dulces, Rocha Province

International Nuclear Information System (INIS)

2002-01-01

On September of the 2002 black san stones deposit were considered Uruguay mining reservation which it last 6 months. They were selected the best deposits areas which were carried out 37 drillings in 727.046 hectare as. The mineralogical composition and uses of Black san stones sampling were analyzed.. Field and laboratory studies were given as methodology. As conclusion they were found 933.000 tons of mineral like ilmenite, zircon, rut ilo, monazite and titanite equivalent to 65% all heavy metals.