Folders: ROOT > ScienceBase Catalog > Geologic Hazards Science Center ( Show direct descendants )
476 results (215ms)
Location
Folder
ROOT _ScienceBase Catalog __Geologic Hazards Science Center Filters
Date Range
Extensions Types
Contacts
Categories Tag Types Tag Schemes |
The Snyder cluster is based on a set of tightly-clustered small events in central Texas near the town of Snyder. It's likely that these are related to injection wells in the area. Magnitudes are up to M4.6. There is very good coverage for direct calibration and many of the more recent events have been recorded by stations at extremely close range, giving excellent depth control. The relocation is done with free depth. Number of events: 90 Calibration type: direct calibration using data to 1.0 degrees; hypocentroid calibration level = 0.3 km Epicentral calibration range: 0 - 1 km Date range:...
The Vlore cluster is named for the city of Vlorë on the coast of southern Albania. The distribution of stations for locatiuon calibration is fairly good, although few of the events in the cluster have readings from a station at near-source distance. Those events that do have close-in data were analyzed to refine the crustal velocity model and corresponding event depths. All events have depth control from near-source or local-distance readings. Nearly all events are recorded at teleseismic distances. The pattern of teleseismic travel time residuals for this cluster is unusual; beyond ~65° there are many stations with strong negative residuals. ...
The Sipovo cluster is named for the town of the same name in Bosnia and Herzegovina. The cluster covers most of central Bosnia and Herzegovina and extends west into southern Croatia. It is larger, geographically, than usual but the seismicity did not divide easily into smaller clusters that could be well calibrated individually. That said, the location calibration of the cluster as a whole is superb. All events have abundant observations at local and regional distances and all events have teleseismic readings, although there are no particularly large events (a 5.4 mb event on November 27, 1990 is the largest). Depth control is mainly from local distance readings. Despite the dense station coverage there are few...
The Tocuyo cluster is named for the town of El Tocuyo in Lara State, western Venezuela. The seismicity is mainly associated with the Cordillera de Mérida. Earthquakes with magnitude 5.0-5.9 are rather common in this area but there are no larger events in recent decades. Station coverage in the region is quite good. All events have depth constraint. Many events have observations of teleseismic depth phases. Most events have depth control from near-source or local-distance readings as well. All events have observations at teleseismic distances. Number of events: 75 Calibration type: direct calibration...
The Raoul cluster is named for Raoul Island in the southwest Pacific, the nearest land above water, but the cluster is over 300 km northeast of the island. The earthquakes occur in the shallow portion of a section of the Kermadec Trench, close to where the Louisville Seamount Chain intersects the trench. Location calibration of this cluster is entirely dependent on data collected by an ocean bottom seismometer deployment in 2007 lead by Ingo Grevemeyer of GeoMAR. Between July and December 2007, the network recorded 16 earthquakes inside the network that were large enough (M4.0-5.2) to be observed at teleseismic stations. These earthquakes can be located very accurately, with good depth control, using only the OBS...
The prague cluster is named for the town of Prague, Oklahoma, U.S.A. The cluster is based on a mainshock-aftershock sequence in November 2011 that was one of the early striking examples of induced seismicity in this formerly very seismically quiescent region. A dense (and well-positioned) temporary network was installed soon after the 5.6 Mw mainshock and the location calibration of this cluster is therefore exceptionally precise. Focal depths are also tightly constrained in free-depth relocations. Unfortunately only a few events are recorded at teleseismic distances so the outlier-identification process has limited power for phase observations beyond regional distance. The original calibrated cluster posted to...
The Pasaman cluster is named for the Pasaman Regency, a district of the West Sumatra province in Indonesia. The cluster is based on the 6.1 Mw earthquake on February 25, 2022. Many aftershocks were well-recorded at short distances; these were used in early relocations to develop the velocity model and the range of focal depths. The final version of the cluster retains only events recorded teleseismically. All events have depth control from near-source and local-distance readings. Azimuthal control for location calibration is excellent. Number of events: 25 Calibration type: direct calibration using data to 1.0 degrees; hypocentroid calibration level = 0.9 km Epicentral calibration range: 1 - 3 km Date range:...
The Wuqia cluster is named after Wuqia Town and County in Xinjiang Uygur Autonomous Region in western China. The cluster includes a 7.4 Ms event on August 23, 1985 that destroyed the town and three events with magnitude 6 or greater (indicated by red stars in the base map). Calibration of this cluster is made possible by the availability of arrival time data at local distances from the 8H and 9H temporary networks deployed by researchers at GFZ [Bloch, W. et al. The 2015–2017 Pamir earthquake sequence: foreshocks, main shocks and aftershocks, seismotectonics, fault interaction and fluid processes. Geophys. J. Int. 233, 641–662 (2022).] and kindly shared by Wasja Bloch and Bernd Schurr. Initial work on this cluster...
The Prince cluster is named for Port au Prince, Haiti. The original version of this cluster (portauprince3.26) included only events related to the deadly 7.2 Ms earthquake on January 12, 2010 and contained only a few events in the 2011-2017 period. On August 14, 2021 A 7.4 Ms earthquake struck a short distance west of the 2010 event. This cluster includes both sequences and more recent, mostly smaller, events that are well-recorded by the seismograph stations installed in the region after these two major earthquakes. These smaller events add considerable statistical power to the location calibration, compared to portauprince3.26. Depth constraint for events prior to end of January 2010 is from teleseismic depth...
The Karasay cluster is named for the village of Kara-Say in the southern part of the Issyk-Kul Region of eastern Kyrgyzstan. It is based on the 7.0 Mw earthquake of January 22, 2024, but most of the events with data for location calibration are located to the northwest of that event, along the southern margin of Lake Issyk-Kul. The cluster includes a dozen of the larger (mainly >M5.0) aftershocks of the January 22 mainshock, and there are several events of magnitude 5.1-5.6 elsewhere in the cluster. Of the January 2024 sequence, only the mainshock and one aftershock have depth constraint from local-distance readings, which are consistent with an estimate of the centroid depth of slip in the mainshock (12 km) from...
The Namangan cluster is named for the city of Namangan on the northern edge of the Fergana Valley in eastern Uzbekistan. The cluster is large in number but relatively few events are observed beyond near-regional distance. The largest events are a series of five M5 earthquakes that occurred very near one another over the course of ~1 year in 1984-85. The decision to retain a large number of smaller events in the cluster was driven by the difficulty in establishing stable statistics when relocating only the larger events. There is considerable scatter in crustal velocities in the region and a large number of outlier readings in the arrival time data set, which could only be resolved by careful analysis of larger sample...
Each of the downloadable files below contains peak ground accelerations on a grid of latitudes and longitudes that cover this geographic region. See the parent item for how Maximum Considered Earthquake Geometric Mean (MCEG) peak ground accelerations are derived from the data in these files.
For background, please see the Parent Item. The attached files below for 8 site classes each provide risk-targeted spectral accelerations (in units of g) for a grid of latitudes and longitudes and 22 spectral periods, including 0.0 seconds for peak ground acceleration (denoted SA0P0). The spectral accelerations for Site Class BC and spectral periods of 0.0, 0.2, and 1.0 seconds were directly derived from the USGS seismic hazard curves released in the "Associated Item"; from these three values, the spectral accelerations for the other site classes and spectral periods were derived indirectly via the FEMA P-2078 procedures cited below, because corresponding USGS hazard curves were not yet available for Guam and the...
Categories: Data
The Odate cluster is named for the city of Odate in Akita Prefecture, northern Honshu, Japan. The cluster mostly consists of crustal events inland; several events in the east have depths greater than 30 km and may be associated with the subducting slab. The cluster includes several M5 events and all events are recorded to teleseismic distances. The distribution of stations for direct calibration is excellent. All events have depth control from near-source or local-distance readings and many of the larger events have consistent teleseismic depth phases. Number of events: 102 Calibration type: direct...
The Yasu cluster is named for the city of Yasu in the central Zagros Mountains of Iran. The cluster contains many events with magnitude 5+ but nothing larger than M5.6. Station coverage for direct calibration is reasonably good since about 2015. All earthquakes have depth control from near- and local-distance readings or from teleseismic depth phases. Most earthquakes were observed to teleseismic distances, but some smaller events observed only to regional distances have been retained to improve the statistical power of the location calibration. Number of events: 144 Calibration type: direct calibration...
The Gansu cluster is named for Gansu Province in northwestern China. The cluster covers much of the southeastern part of the province. It contains two M6 earthquakes, the 6.2 Ms Minxian-Zhangxian event on July 21, 2013 and the 6.1 Ms Jishishan event on December 18, 2023, and many M5 earthquakes. As with most of the calibrated clusters in China, location calibration of the Gansu cluster is based mainly on data collected by Sun Ruomei from the provincial networks for the period 1967-2004. The station distribution in this part of China is somewhat dispersed so the geographic area of the cluster is larger than optimal. Although the calibration of the hypocentroid is very strong the uncertainties of individual events,...
The Sikeston cluster is named for the Town of Sikeston in southeast Missouri, U.S.A. This is part of the New Madrid seismic zone, the region shaken by four earthquakes in the 7.2-8.2 Mw range in 1811-12. The cluster contains no event larger than 4.3 mb but the region is heavily instrumented and many smaller events are well-recorded. There are few arrival time readings beyond an epicentral distances of about 15°. Events earlier than about 2010 are well recorded but the modern seismograph network in the region has changed substantially and there were connectivity problem when older events were included in the cluster. All events could be relocated with free depth but in some cases the depth has been adjusted manually...
The Gokova cluster is named for the Gulf of Gokova in Western Turkey. The cluster includes the Mw 6.6 Bodrum-Kos earthquake on July, 20 2017 and 24 of its aftershocks, as well as many earlier events dating back to 1987. This cluster uses phase arrival data from AFAD, KOERI, ISC, USGS NEIC, and NOA-IG. Focal depths are constrained for most of the 192 events in the cluster; the remainder are held at a default depth of 10 km. Depths for 58 events were determined by near-distance data and the depths of the 117 others are constrained by local-distance data. Further information about this cluster is contained in Karasözen et al. 2018, GJI, The 20 July 2017 Mw6.6 Bodrum-Kos earthquake illuminates active faulting in the...
|
|
