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ShakeMap is a product of the USGS Earthquake Hazards Program in conjunction with the regional seismic networks. ShakeMaps provide near-real-time maps of ground motion and shaking intensity following significant earthquakes. These maps are used by federal, state, and local organizations, both public and private, for post-earthquake response and recovery, public and scientific information, as well as for preparedness exercises and disaster planning.
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The NEIC global earthquake bulletin is called the Preliminary Determination of Epicenters or PDE, and is one of many discrete products in the ANSS Comprehensive Catalog (ComCat). We use the word "Preliminary" for our final bulletin because the Bulletin of the International Seismological Centre is considered to be the final global archive of parametric earthquake data, in other words phase arrival (“pick”) times and amplitudes.
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Probabilistic seismic hazard maps were prepared for Alaska portraying peak horizontal ground acceleration and horizontal spectral response acceleration for 0.2, 0.3, and 1.0 second periods with probabilities of exceedance of 10% in 50 years and 2% in 50 years. This particular data set is for peak horizontal acceleration with a 10% probability of exceedance in 50 years. All of the maps were prepared by combining hazard derived from spatially-smoothed historic seismicity with hazard from fault-specific sources. The acceleration values contoured are the random horizontal component. The reference site condition is firm rock, defined as having an average shear-wave velocity of 760 m/sec in the top 30 meters corresponding...
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New active-source shallow seismic (shear-wave and acoustic-wave) measurements were obtained at 18 prioritized seismic monitoring station locations in the north San Francisco Bay area to measure site-specific ground motion amplification effects, soil depth, depth to bedrock (Z1.0 Vs=1 km/s), calculate site specific velocity-depth profiles and Vs30, and develop NEHRP site classifications for each location. This study was led by Principal Investigators Jamey Turner, Cooper Brossy, and Daniel O’Connell and field data were acquired by Glendon Adams and Lincoln Steele. Seismic monitoring sites that recorded high PGA values during the M6.0 Napa earthquake, proximal to higher population densities, and sites recommended...
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Staff from Alaska Earthquake Center, Geophysical Institute and Alaska Division of Geological & Geophysical Surveys evaluated potential tsunami hazards for the city of Sand Point, on Popof Island in the Shumagin Islands archipelago. We numerically modeled the extent of inundation from tsunami waves generated by local and distant earthquake sources. We considered the results in light of historical observations. The worst-case scenarios are defined by analyzing results of the sensitivity study of the tsunami dynamics with respect to different slip distributions along the Aleutian megathrust. For the Sand Point area, the worst-case scenarios are thought to be thrust earthquakes in the Shumagin Islands region with magnitudes...
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A scenario represents one realization of a potential future earthquake by assuming a particular magnitude, location, and fault-rupture geometry and estimating shaking using a variety of strategies. In planning and coordinating emergency response, utilities, local government, and other organizations are best served by conducting training exercises based on realistic earthquake situations—ones similar to those they are most likely to face. ShakeMap Scenario earthquakes can fill this role. They can also be used to examine exposure of structures, lifelines, utilities, and transportation corridors to specified potential earthquakes. A ShakeMap earthquake scenario is a predictive ShakeMap with an assumed magnitude and...
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The data set consists of time, depth, reflection coefficient synthetic, sonic velocity, density, and amplitude used to create synthetic seismogram - City of Hollywood Utility, G-2961, (HOL-IW1), Broward County, Florida.
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In March 2015, the U.S. Geological Survey acquired seismic reflection and refraction data along an approximately 2.8-km-long profile across northwest-trending San Andreas Fault splays located at the Dos Palmas Preserve east of Salton Sea. To acquire the reflection and refraction data, we collocated shots and geophones, spaced every 3 m along the profile. We used 933 SercelTM L40A P-wave (40-Hz vertical-component) geophones with a sensitivity of 22.34 volts/meter/second to record 925 P-wave shots. We generated P-wave data using one of two active sources: 400-grain Betsy-SeisgunTM shots at approximately every 90 m and a 3.5-kg sledgehammer and steel plate combination at every 3 m between the seisgun shots. All data...
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Subduction zones are home to the most seismically active faults on the planet. The shallow megathrust interface of subduction zones host our largest earthquakes, and are the only faults capable of M9+ ruptures. Despite these facts, our knowledge of subduction zone geometry - which likely plays a key role in determining the spatial extent and ultimately the size of subduction zone earthquakes - is incomplete. Here we calculate the three- dimensional geometries of all active global subduction zones. The resulting model - Slab2 - provides for the first time a comprehensive geometrical analysis of all known slabs in unprecedented detail. ##### This distribution includes models of three-dimensional slab geometry under...
The data from the borehole strainmeter network set consists of raw data from the telemetry, state of health measurements, environmental measurement of temperature and pressure, and processed borehole strainmeter data. For each strainmeter site in this network, there will be a mix of raw data, SOH, environmental data, and processed strain. Each channel of data consists of a time of observation, usually 10-minute intervals, and a number that is either telemetry counts (which is proportional to the voltage output by the instrument), or in units of strain, which are either in part per million or parts per billion. Processed strain will be free of glitches and other artifacts and are corrected for changes in atmospheric...
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Probabilistic seismic hazard maps were prepared for Alaska portrayingpeak horizontal ground acceleration and horizontal spectral responseacceleration for 0.2, 0.3, and 1.0 second periods with probabilitiesof exceedance of 10% in 50 years and 2% in 50 years. This particulardata set is for horizontal spectral response acceleration for 0.2 secondperiod with a 2% probability of exceedance in 50 years. All ofthe maps were prepared by combining hazard derived from spatially-smoothed historic seismicity with hazard from fault-specific sources.The acceleration values contoured are the random horizontal component.The reference site condition is firm rock, defined as having an averageshear-wave velocity of 760 m/sec in the...
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This cover consists of location and size information for historicaland recent earthquakes that caused Modified Mercalli Intensity(MMI) VI (6) or higher in the map area. There were 26 earthquakesthat caused that level of damage. The most reknown are thefour earthquakes in the 1811- 1812 sequence; two on Dec 16,1811, and one each on Jan 23, 1812, and Feb 7, 1812. Theircalculated Moment Magnitudes were 8.1, 7.2, 7.8, and 8.0,respectively. The most recent damaging earthquake was on June 10,1987 near Olney, Illinois. It had a Moment Magnitude of 5.2.
Tags: 1500 - Hazards, 1501 - Earthquakes, 17025 = Clay, 17047 = Edwards, 17055 = Franklin, All tags...
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Compiled Vs30 measurements obtained by studies funded by the U.S. Geological Survey (USGS) and other governmental agencies. Thus far, there are 2,997 sites in the United States, along with metadata for each measurement from government-sponsored reports, Web sites, and scientific and engineering journals. Most of the data originated from publications directly reporting the work of field investigators. A small subset (less than 20 percent) of Vs30 values was previously compiled by the USGS and other research institutions. Whenever possible, Vs30 originating from these earlier compilations were crosschecked against published reports. Both downhole and surface-based Vs30 estimates are represented. Most of the VS30 data...
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The data set consists of time, depth, reflection coefficient synthetic, sonic velocity, density, and amplitude used to create synthetic seismogram - Deerfield Beach BHC, G-2968, Broward County, Florida.
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The data set consists of time, depth, reflection coefficient synthetic, sonic velocity, density, and amplitude used to create synthetic seismogram - City of Sunrise Utility, SUN-I3, Broward County, Florida.
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In April 2017, the U.S. Geological Survey acquired high resolution P- and S-wave seismic data across the suspected trace of the West Napa Fault zone in St. Helena, California. We acquired seismic reflection, refraction, and guided-wave data along a 215-m-long profile across the expected trend of the West Napa Fault zone. To acquire the reflection and refraction data, we co-located shots and geophones, spaced every 2 m along the profile. We used 109 SercelTM L40A P-wave (40-Hz vertical-component) geophones with a sensitivity of 22.34 volts/meter/second to record 108 P-wave shots, and 109 SercelTM L28-LBH S-wave (4.5-Hz horizontal-component) geophones with a sensitivity of 31.3 volts/meter/second to record 108 S-wave...


map background search result map search result map Seismic-Hazard Maps for Alaska and the Aleutian Islands: PGA050 Seismic-Hazard Maps for Alaska and the Aleutian Islands: 5HZ250 Seismotectonic maps in the vicinity of the lower Wabash Valley,Illinois, Indiana, and Kentucky - Digital Spatial Database:Damaging Earthquakes G-2946 : Synthetic Seismogram Data for Correlation Between Seismic-Reflection Profiles and Well Data, Broward County, Florida G-2968 : Synthetic Seismogram Data for Correlation Between Seismic-Reflection Profiles and Well Data, Broward County, Florida G-2961 (HOL-IW1) : Synthetic Seismogram Data for Correlation Between Seismic-Reflection Profiles and Well Data, Broward County, Florida SUN-I3 : Synthetic Seismogram Data for Correlation Between Seismic-Reflection Profiles and Well Data, Broward County, Florida Tsunami inundation maps for the city of Sand Point, Alaska 2017 seismic imaging of the West Napa Fault Zone, St. Helena, California 2015 high resolution seismic acquisition at Dos Palmas Preserve, Mecca, California 2015 high resolution seismic acquisition at Dos Palmas Preserve, Mecca, California Tsunami inundation maps for the city of Sand Point, Alaska 2017 seismic imaging of the West Napa Fault Zone, St. Helena, California G-2946 : Synthetic Seismogram Data for Correlation Between Seismic-Reflection Profiles and Well Data, Broward County, Florida G-2968 : Synthetic Seismogram Data for Correlation Between Seismic-Reflection Profiles and Well Data, Broward County, Florida G-2961 (HOL-IW1) : Synthetic Seismogram Data for Correlation Between Seismic-Reflection Profiles and Well Data, Broward County, Florida SUN-I3 : Synthetic Seismogram Data for Correlation Between Seismic-Reflection Profiles and Well Data, Broward County, Florida Seismotectonic maps in the vicinity of the lower Wabash Valley,Illinois, Indiana, and Kentucky - Digital Spatial Database:Damaging Earthquakes Seismic-Hazard Maps for Alaska and the Aleutian Islands: PGA050 Seismic-Hazard Maps for Alaska and the Aleutian Islands: 5HZ250