Folders: ROOT > ScienceBase Catalog > Geologic Hazards Science Center ( Show direct descendants )
469 results (292ms)
Location
Folder
ROOT _ScienceBase Catalog __Geologic Hazards Science Center Filters
Date Range
Extensions Types
Contacts
Categories Tag Types Tag Schemes |
The Gazli cluster is named for the town of Gazli in northwest Uzbekistan. The source region was nearly aseismic until April 8, 1976 when a large (Ms 7.0) earthquake initiated several years of very active seismicity, including another Ms 7.0 event in May 1976 and a third Ms 7.0 event in March 1984. Low-level activity continues currently. It is generally believed that the sequence represents an episode of induced seismicity related to large-scale gas extraction industry in the area. The cluster is formed mainly from events that have depth control from teleseismic relative depth phases, plus one event, on June 25, 1991, that was recorded by a temporary seismic network (operated by LGIT, Grenoble, France) and was well-enough...
The Valparaiso cluster is named for the nearby city of Valparaiso, Chile. The cluster is based on a set of arrival time readings from a deployment of ocean bottom seismometers, hydrophones and a temporary land-based stations for several months in 2001 that were kindly provided by Frederik Tilmann (GeoForschungsZentrum). Most of the recorded events are fairly small, the largest having magnitude 4.8mb, but 34 events could be well located with free-depth solutions and linked to larger events in the region through readings at permanent seismograph stations. The remaining events in the cluster are ones for which depth control is available from at least one station close to the epicenter, i.e., within a distance of 1-1.5...
The Jiashi cluster is named for Jiashi County of the Xinjiang Autonomous Region of NW China. It is composed mainly of events related to the earthquake sequence in early 1997, including two M5.9 events on January 21 and an M6.1 event on April 11. There were many other moderate-sized events in the sequence, which occurred near the western margin of the Tarim Basin and the border with Kyrgyzstan. As a result this cluster is very rich in arrival time data at far-regional and teleseismic distances. Number of events: 125 Calibration type: direct calibration using data to 1.2 degrees; hypocentroid calibration level = 2.7 km Epicentral calibration range: 3 - 5 km Date range: 19771218 - 20041007 Latitude range: 39.303...
The 2002 U.S. Geological Survey (USGS) National Seismic Hazard Maps display earthquake ground motions for various probability levels across the United States and are applied in seismic provisions of building codes, insurance rate structures, risk assessments, and other public policy. This update of the maps incorporates new findings on earthquake ground shaking, faults, seismicity, and geodesy. The resulting maps are derived from seismic hazard curves calculated on a grid of sites across the United States that describe the frequency of exceeding a set of ground motions.
Types: Citation;
Tags: B/C site class boundary,
EHP,
Earthquake Hazards Program,
GHSC,
Geologic Hazards Science Center,
Wildfire can significantly alter the hydrologic response of a watershed to the extent that even modest rainstorms can produce dangerous flash floods and debris flows. The USGS conducts post-fire debris-flow hazard assessments for select fires in the Western U.S. We use geospatial data related to basin morphometry, burn severity, soil properties, and rainfall characteristics to estimate the probability and volume of debris flows that may occur in response to a design storm.
The Aqaba cluster is named for the Gulf of Aqaba, between the Sinai Peninsula and Saudia Arabia. The cluster includes significant earthquake sequences in 1993 (5.8 MS) and 1995 (7.1 MS). After the 1995 sequence a number of seismic stations were installed around the Gulf and readings from those stations for more recent events form the basis for the calibration. Number of events: 49 Calibration type: direct calibration using data to 1.0 degrees; hypocentroid calibration level = 1.7 km Epicentral calibration range: 2 - 5 km Date range: 19930730 - 20161129 Latitude range: 28.488 - 29.345 Longitude range: 34.530 - 34.979 Depth range: 12.0 - 30.8 Magnitude range: 3.7 - 7.1
The Magna cluster is named for the town of Magna, Utah, U.S.A., on the southern shore of the Great Salt Lake and the northwestern suburbs of Salt Lake City. The cluster is built around a 5.7 Mw earthquake there on March 18, 2020. The next largets event is a 4.6 Mw aftershock. The local network is quite dense so small, earlier events in the area could be included in the cluster. 18 of those events were relocated in a free-depth inversion to refine the crustal velocity model and event depths. All events in the cluster have depth control from near-source and local distance arrival times. Number of...
The Simeulue cluster is named for the island of Simeulue off the north coast of Sumatra, Indonesia. The cluster is based on 33 events recorded by a temporary network of OBS's from October 2005 to February 2006 to record aftershocks of the Mw 8.6 earthquake of March 28, 2005 (Nias-Simeulue), which was itself probably triggered by the great Sumatra earthquake of December 26, 2004 (Mw 9.1). The Nias-Simeulue earthquake is included in the cluster. Readings from the OBS network (kindly provided by Frederick Tilmann, GFZ Potsdam) provide the calibration of the cluster, which was expanded with moderate-sized events since 2006 to improve the set of teleseismic arrival time data. Many events in the cluster have good datasets...
The Caldiran cluster is named after the town of Cadiran in the district of Van, Turkey. This cluster consists of 83 events, including the magnitude 7.3 Caldiran earthquake on November 24, 1976 and five of its aftershocks, as well as several recent moderate magnitude events in 2000s, the largest being the magnitude 5.1 October 20, 2003 earthquake. A. Ghods repicked many of the arrival times from Iranian networks, including S-P data from the INSM network of accelerometers (BHRC). Focal depths of 24 events are set with near-distance picks, and 44 are constrained with local-distance picks. The remaining events in the cluster are held at a default depth of 12 km. ...
The Toktogul cluster is named for town of Toktogul, Kyrgyzstan, and the nearby Reservoir of the same name. The cluster is divided into two subclusters, one north of the reservoir and one to the south. The cluster includes the Ms 7.3 earthquake on August 18, 1992 that devastated the town of Susamyr about 40 km to the east, and a half-dozen of the larger aftershocks. On December 22, 2009 a large (4.4 mb) chemical explosion was used in the construction of the hydroelectric dam that created the Toktogul Reservoir. The shot, known as "Kambarata" and included in the cluster, was well instrumented and serves as a calibration event for the cluster. Calibration of the cluster is done with direct calibration, but the ground...
The Chiles cluster is named for Chiles Volcano in northern Ecuador. The cluster is composed mainly of earthquakes associated with a seismic crisis at the volcano in 2014, including a 6.0 mb event on October 20, 2014. About half the events are recorded at teleseismic distances. The station coverage is reasonably good and all events have depth control. Number of events: 31 Calibration type: direct calibration using data to 1.0 degrees; hypocentroid calibration level = 1.8 km Epicentral calibration range: 2 - 4 km Date range: 19970219 - 20150124 Latitude range: 0.439 - 1.250 Longitude range:...
The Nurek cluster is named for the Nurek Dam and Reservoir along the Vakhsh River in Tajikistan. The cluster includes several earthquakes in the low-5 magnitude range. Most of the seismicity appears to be associated with the reservoir and some of the seismicity may have been induced by the filling of the reservoir. It is notable that the the period 1999-2010 produced no earthquakes large enough to be included in the cluster. Number of events: 43 Calibration type: direct calibration using data to 1.2 degrees; hypocentroid calibration level = 1.2 km Epicentral calibration range: 2 - 5 km Date...
The Tocopilla cluster is named for the city of Tocopilla in northern Chile that is on its southern edge. The cluster includes an Mw 6.3 earthquake on September 11, 2020. A few small events that were recorded only locally are included to improve the statistical power of the calibration, but most events are observed to teleseismic distances. All events have depth control from readings at near-source or local distances, and about one third of the events also have teleseismic depth phases readings that are consistent with the inferred depths. Number of events: 48 Calibration type: direct calibration...
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.
Types: Citation;
Tags: ANSS,
Advanced National Seismic System,
ComCat,
Comprehensive Earthquake Catalog,
Earth,
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...
Types: Citation;
Tags: Earthquake Hazards Program,
GHSC,
Geologic Hazards Science Center,
ShakeMap,
USGS,
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...
Categories: Data;
Types: Citation,
Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: California,
EHP,
Earthquake Hazards Program,
GHSC,
Geologic Hazards Science Center,
The Okinawa cluster is named for the island of Okinawa in the Ryukyu Islands. Although there are deeper events in the area, only events with depths less than about 35 km were retained in the cluster. The cluster contains one large event, an Ms 6.5 event on March 2, 1980 to the west of the island that is likely associated with back-arc spreading. All events have depth constraint from arrivals at near- or local-distances, or from teleseismic depth phases in a few cases. Although the setting is broadly oceanic, the Ryukyu Islands are thought to be part of a remannt continental sliver, so it is not so surprising that a crustal model very close to ak135 fits the observed arrival time data well. ...
The Siah Kuh cluster is named after the village of Siah Kuh (Black Mountain) in Gilan Province, Iran. It consists of only 16 events, the largest being the M4.3 event on September 5, 2005. There's a fairly large azimuthal gap to the east, but the cluster is well calibrated at a level of 1.4 km by using data up to 1.6 degrees. Focal depths of almost all events are constrained with local-distance readings, except for the oldest event in the cluster (January 6, 2005) which is set to a default of 11 km. Number of events: 16 Calibration type: direct calibration using data to 1.6 degrees; hypocentroid...
The Hakodate cluster is named for the city of Hakodate at the south end the island of Hokkaido, Japan. The cluster extends southward to the northern tip of Honshu. Over half the events in the cluster are associated with an earthquake swarm in late March 2000 on the southern flank of Mt. Usu, an active volcano in southern Hokkaido. The distribution of stations is quite good and location calibration is straight-forward. Number of events: 39 Calibration type: direct calibration using data to 1.0 degrees; hypocentroid calibration level = 1.1 km Epicentral calibration range: 1 - 2 km Date range:...
|
|
