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The U. S. Geological Survey (USGS) makes long-term seismic hazard forecasts that are used in building codes. The hazard models usually consider only natural seismicity; non-tectonic (man-made) earthquakes are excluded because they are transitory or too small. In the past decade, however, thousands of earthquakes related to underground fluid injection have occurred in the central and eastern U.S. (CEUS), and some have caused damage. In response, the USGS is now also making short-term forecasts that account for the hazard from these induced earthquakes. Seismicity statistics are analyzed to develop recurrence models, accounting for catalog completeness. In the USGS hazard modeling methodology, earthquakes are counted...
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The New Madrid Seismic Zone presents significant seismic hazard to the central and eastern United States. We mapped newly-identified coseismic ridge-spreading features, or sackungen, in the bluffs east of the Mississippi River in western Tennessee. We use this mapping dataset in an accompanying manuscript to show that sackungen form during earthquakes on the Reelfoot fault and may fail in preferred orientations. Ultimately, these data can be used to infer fault source and mechanism and improve the paleoseismic record used in hazard models.
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Earthquake instability occurs as a result of strength loss during sliding on a fault. It has been known for over 50 years that fault compaction or dilatancy may cause significant weakening or strengthening by dramatically changing the fluid pressure trapped in faults. Despite this fundamental importance, we have no real understanding of the exact conditions that lead to compaction or dilation during nucleation or rupture. To date, no direct measurements of pore pressure changes during slip in hydraulically isolated faults have been reported. We show direct examples of fluid pressure variations during nucleation and rupture using a miniature pressure transducer embedded in an experimental fault. We demonstrate that...
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We present high-resolution (10-cm pixel) digital surface models (DSMs) generated for the northern 16 km of the surface rupture associated with the 1983 Mw 6.9 Borah Peak earthquake. These DSMs were generated using Agisoft Photoscan (and Metashape) image-based modeling software and low-altitude aerial photographs acquired from unmanned aircraft systems and a tethered balloon. DSM files consist of GeoTIFFs with georeferencing information stored in the file headers.
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This ScienceBase entry contains three seismic catalogs supporting and described by the manuscript - Koper, K. D., Pankow, K. L., Pechmann, J. C., Hale, J. M., Burlacu, R., Yeck, W. L., et al (2018). Afterslip Enhanced Aftershock Activity During the 2017 Earthquake Sequence Near Sulphur Peak, Idaho. Geophysical Research Letters, 45. https://doi.org/10.1029/2018GL078196. These are included in three separate catalog files: the University of Utah Seismograph Stations (UUSS) absolute locations, the MLOC relocations, and the GrowClust relocations. The absolute USGS locations are available from the USGS ComCat (https://earthquake.usgs.gov/data/comcat/).
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We acquired multiple types of controlled-source seismic data across the Hollywood Fault in Hollywood, Calif., and the Santa Monica Fault in Beverly Hills, Calif., in May and June of 2018. We acquired two separate profiles across the Hollywood Fault, and from those data, we can evaluate multiple seismic datasets, including guided-wave data, tomographic Vp data, and tomographic Vs data. From the datasets, we can calculate multiple seismic models, including Vp/Vs and Poisson's ratio models derived from tomographic Vp and Vs data, Rayleigh-wave-based Vs models, Love-wave-based Vs models, Vp/Vs and Poisson's ratio models (derived from combinations of tomographic-based Vp and surface-wave-based Vs models), P-wave reflection...
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A 3D temperature model is constructed in order to support the estimation of physical parameters within the USGS National Crustal Model. The crustal model is defined by a geological framework consisting of various lithologies with distinct mineral compositions. A temperature model is needed to calculate mineral density and bulk and shear modulus as a function of position within the crust. These properties control seismic velocity and impedance, which are needed to accurately estimate earthquake travel times and seismic amplitudes in earthquake hazard analyses. The temperature model is constrained by observations of surface temperature, temperature gradient, and conductivity, inferred Moho temperature and depth, and...
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The 2014 update of the U.S. Geological Survey (USGS) National Seismic Hazard Model (NSHM) for the conterminous United States (2014 NSHM; Petersen and others, 2014; https://pubs.usgs.gov/of/2008/1128/) included probabilistic ground motion maps for 2 percent and 10 percent probabilities of exceedance in 50 years, derived from seismic hazard curves for peak ground acceleration (PGA) and 0.2 and 1.0 second spectral accelerations (SAs) with 5 percent damping for the National Earthquake Hazards Reduction Program (NEHRP) site class boundary B/C (time-averaged shear wave velocity in the upper 30 meters [VS30]=760 meters per second [m/s]). This data release provides 0.1 degree by 0.1 degree gridded seismic hazard curves,...
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These data are from a 3-month long deployment of nodal seismometers that ran from May 18th, 2022 until September 1st, 2022 as part of a Distributed Acoustic Sensing (DAS) experiment above the Gorda plate (McGuire, et al., 2022). The sensors were deployed at 44 locations along Old Arcata Rd between Arcata and Eureka California (Figure 1); these locations track the approximate location of the fiber optic cable used as part of the DAS experiment. The instruments have a battery recording life of approximately one month and were swapped out in the same locations in Mid-June, and Mid-July. Thus, there are 132 instruments that were deployed at 44 distinct locations.
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The data for this release is an ASCII file containing grid points of Cascadia P- and S-wave velocity models. The model volume was developed to include the Cascadia subduction zone for purposes of ground motion simulation. The description of the model and background of its development is provided in the associated Open-File Report. The grid points are given in Universal Transverse Mercator (UTM) Zone 10 North coordinates for East and North locations, and the grid point depths are given in meters below mean sea level. Grid point spacing is 500 meters in each ordinal direction. The model region extends approximately from 40.2°N to 50°N latitude, and approximately from 122°W to 129°W longitude. The maximum depth of...
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In August 2017, the U.S. Geological Survey acquired high-resolution P- and S-wave seismic data near six Southern California Seismic Network (SCSN) recording stations in southern California: CI.OLI Olinda; CI.SRN Serrano; CI.MUR Murrieta; CI.LCG La Cienega; CI.RUS Rush; and CI.STC Santa Clara (Figure 1). These strong-motion recording stations are located inside Southern California Edison electrical substations, critical infrastructures that provide essential services to millions of customers. The primary goals of the seismic survey were to understand the potential for amplified ground shaking and to evaluate lateral variability in shear-wave velocity at these sites. We deployed up to 88 geophones at 2-m or 4-m...
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This data release complements Murray et al. (2023) which presents a framework for incorporating earthquake magnitude estimates based on real-time Global Navigation Satellite System (GNSS) data into the ShakeAlert® earthquake early warning system for the west coast of the United States. Murray et al. (2023) assess the impact of time-dependent noise in GNSS real-time position estimates on the reliability of earthquake magnitudes estimated using such data. To do so they derived peak ground displacement (PGD) estimates from time series of background noise in GNSS real-time positions. These noise-only PGD measurements were used as input to a published empirical relationship to compute magnitude for hypothetical earthquakes...
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In May 2019, the U.S. Geological Survey acquired high resolution P- and S-wave seismic data near six seismic network recording stations in San Bernardino County, California: Southern California Seismic Network CI.CLT Calelectic, CI.MLS Mira Loma, CI.CJM Cajon Mountain and CI.HLN Highland; California Strong Motion Instrumentation Program station CE.23542; and US National Strong-Motion Network station NP.5326 (Figure 1). The primary goals of the seismic survey were to better understand the potential for amplified ground shaking, to evaluate lateral variability in shear-wave velocity, and to calculate Vs30 at these sites. We deployed up to 67 DTCC SmartSolo 3-component seismometer systems ("nodes") at 2-m spacing...
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This release provides inventories of georeferenced evidence pertaining to extreme waves on Anegada, a low Caribbean island perched south of the Puerto Rico Trench: CORAL BOULDERS AND COBBLES -- Derived offshore, found inland. Boulder star coral Orbicella franksii (37 localities), brain coral Pseudodiploria strigosa (171), elkhorn coral Acropora palmata (36), mustard hill coral Porites astreoides (29). LIMESTONE BOULDERS AND COBBLES -- Derived and found onshore (633). MOLLUSCAN SHELLS -- Queen conch Aliger gigas, discarded by precolonial fishers (12 onshore heaps) and by modern fishers (40 offshore heaps); individual conch shells deposited inland by precolonial sea flood (59); tiger lucine Codakia orbicularis, also...
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The dataset contains the catalog of 5446 events and arrival times resulting from subspace detection processing and relocation in the for the 2011 Prague, Oklahoma, aftershock sequence. Lines beginning with "E" contain event information in the following order: event ID, origin year, origin month, origin day, origin hour, origin minute, origin second, latitude, longitude, depth, and magnitude. Lines beginning with "P" contain phase information in the following order: event ID, network, station, phase, phase arrival year, phase arrival month, phase arrival day, phase arrival hour, phase arrival minute, phase arrival second.
Enhanced reservoir connectivity generally requires maximizing the intersection between hydraulic fracture (HF) and preexisting underground natural fractures (NF), while having the hydraulic fracture continue to propagate across the natural fractures. Observations of downhole core samples suggest that these natural fractures are in fact veins filled with minerals such as calcite (Mighani et al., 2016). We study this interaction during the approach of a hydraulic fracture to a smooth saw-cut fracture under triaxial stress conditions. The specimen is Solnhofen limestone, a fine-grained (<5 µm grain), low permeability (<10 nD) carbonate. The differential stress (1-20 MPa) and inclination of the fault which determines...
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This dataset represents the spatial locations of all modeled aftershocks magnitude 2.5 and greater resulting from the HayWired M7.0 mainshock occurring on April 18, 2018 along the Hayward Fault. The date/time, horizontal and vertical location, and sequence position is provided for each aftershock. The spatial extent covers 24 counties in whole or in part, corresponding to the modeled shaking extent for the HayWired mainshock ShakeMap (available at https://earthquake.usgs.gov/scenarios/eventpage/ushaywiredm7.05_se#shakemap). The sequence is simulated based on several known statistical relationships and generated using an epidemic type aftershock sequence (ETAS) model, resulting in one possible aftershock sequence....
These maps show the potential of widespread slope failures, in terms of landslide probabilities and displacement, triggered by a M7.0 scenario earthquake on the Hayward Fault in the 10-county area surrounding the San Francisco Bay region, California. The likelihood of landsliding was evaluated using an equation developed by Jibson and others (2000) that estimates landslide probability as a function of predicted Newmark displacement. Based on this equation, four landslide probability categories are established with their corresponding percent likelihood and displacement ranges: Low (0-2%; 0-1 cm), Moderate (2-15%; 1-5 cm), High (15-32%; 5-15 cm), and Very High (>32%; >15 cm).The seismic-landslide probability map...
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These data are damage and loss estimates obtained from various Hazus outputs covering all census tracts in 17 counties in and around the San Francisco Bay region in California, for the HayWired earthquake scenario and sixteen M5 or greater aftershocks occurring in the region during the two years following the HayWired mainshock. The HayWired earthquake scenario is a magnitude 7.0 earthquake hypothesized to occur on the Hayward Fault on April 18, 2018, with an epicenter in the city of Oakland, CA. The estimates contained in this dataset are a subset of the many results products generated by FEMA's Hazus-MH 2.1 application, and reflect potential damage due to the HayWired earthquake scenario mainshock and its aftershocks....
map background search result map search result map Point locations for earthquakes M2.5 and greater in a two-year aftershock sequence resulting from the HayWired scenario earthquake mainshock (4/18/2018) in the San Francisco Bay area, California Aftershock Catalog for the November 2011 Prague, Oklahoma, Earthquake Sequence Data for P- and S-wave Seismic Velocity Models Incorporating the Cascadia Subduction Zone for 3D Earthquake Ground Motion simulations- Update for Open-File Report 2007-1348 Data Release for Additional Period and Site Class Maps for the 2014 National Seismic Hazard Model for the Conterminous United States Earthquake Catalogs supporting manuscript "Afterslip Enhanced Aftershock Activity During the 2017 Earthquake Sequence Near Sulphur Peak, Idaho" Data Set S1 for "Coseismic Sackungen in the New Madrid Seismic Zone, USA" Digital Surface Models for the northern 16 km of the 1983 Borah Peak earthquake rupture, northern Lost River fault zone (Idaho, USA) Selected products of the scenario HayWired earthquake sequence Hazus analyses for 17 counties in the San Francisco Bay region, California Grids in support of the U.S. Geological Survey Thermal Model for Seismic Hazard Studies Data from the manuscript: Direct evidence for fluid pressure, dilatancy, and compaction affecting slip in isolated faults Data Release for the 2018 U.S. Geological Survey–California Geological Survey Fault-Imaging Surveys Across the Hollywood and Santa Monica Faults, Los Angeles County, California High-resolution seismic data acquired at six Southern California Seismic Network (SCSN) recording stations in 2017 High-resolution seismic data acquired at six seismic network recording stations in San Bernardino County, California in 2019 Spring 2022 Arcata to Eureka, California, Distributed Acoustic Sensing (DAS) experiment: Nodal Seismometer data Input for assessing the impact of noisy data on earthquake magnitude estimates derived from peak ground displacement measured with real-time Global Navigation Satellite System data Field evidence noted in 2008 to 2023 that pertains to sea floods of the past millennium on Anegada, British Virgin Islands Data from the manuscript: Direct evidence for fluid pressure, dilatancy, and compaction affecting slip in isolated faults Digital Surface Models for the northern 16 km of the 1983 Borah Peak earthquake rupture, northern Lost River fault zone (Idaho, USA) Field evidence noted in 2008 to 2023 that pertains to sea floods of the past millennium on Anegada, British Virgin Islands Aftershock Catalog for the November 2011 Prague, Oklahoma, Earthquake Sequence High-resolution seismic data acquired at six seismic network recording stations in San Bernardino County, California in 2019 Data Set S1 for "Coseismic Sackungen in the New Madrid Seismic Zone, USA" Earthquake Catalogs supporting manuscript "Afterslip Enhanced Aftershock Activity During the 2017 Earthquake Sequence Near Sulphur Peak, Idaho" Data Release for the 2018 U.S. Geological Survey–California Geological Survey Fault-Imaging Surveys Across the Hollywood and Santa Monica Faults, Los Angeles County, California High-resolution seismic data acquired at six Southern California Seismic Network (SCSN) recording stations in 2017 Spring 2022 Arcata to Eureka, California, Distributed Acoustic Sensing (DAS) experiment: Nodal Seismometer data Point locations for earthquakes M2.5 and greater in a two-year aftershock sequence resulting from the HayWired scenario earthquake mainshock (4/18/2018) in the San Francisco Bay area, California Selected products of the scenario HayWired earthquake sequence Hazus analyses for 17 counties in the San Francisco Bay region, California Data for P- and S-wave Seismic Velocity Models Incorporating the Cascadia Subduction Zone for 3D Earthquake Ground Motion simulations- Update for Open-File Report 2007-1348 Input for assessing the impact of noisy data on earthquake magnitude estimates derived from peak ground displacement measured with real-time Global Navigation Satellite System data Data Release for Additional Period and Site Class Maps for the 2014 National Seismic Hazard Model for the Conterminous United States Grids in support of the U.S. Geological Survey Thermal Model for Seismic Hazard Studies