System to collect and analyze data on significant earthquakes
Logo of the ANSS
The Advanced National Seismic System (ANSS) is a collaboration of the United States Geological Survey (USGS) and regional, state, and academic partners that collects and analyzes data on significant earthquakes to provide near real-time (generally within 10 to 30 minutes[1]) information to emergency responders and officials, the news media, and the public.[2] Such information is used to anticipate the likely severity and extent of damage, and to guide decisions on the responses needed.[3]
Data is collected by eleven regional seismic networks and the National Seismic Network ("ANSS backbone") of dedicated stations, with additional inputs from overseas seismic networks. Analysis is done at the regional data centers, and at the USGS National Earthquake Information Center (NEIC),[4] with the results posted at the USGS earthquake web page (https://earthquake.usgs.gov/earthquakes/).
The National Strong Motion Project of the ANSS has instrumented 168 structures to record their response to very strong shaking. This data is used in research on earthquake-resistant engineering.[5]
Products and services
The ANSS provides a range of products and services:[6]
ShakeMap: a map of the anticipated severity and extent of ground shaking, based on the measured strength of ground shaking and known characteristics of the affected locality.
ShakeCast: automated delivery of ShakeMaps customized for critical infrastructure, providing an estimate of shaking experienced.
The ANSS Comprehensive Catalog (ComCat) is a repository of data from the participating seismic networks. For significant earthquakes the NEIC prepares a summary of the tectonic setting, nearby fault systems, and historical seismicity.
The regional networks are deemed authoritative for the location and magnitude of earthquakes in their region. The NEIC receives additional data from about 3,000 stations around the world, and provides backup if a regional network is unable to communicate.
↑ USGS Circular 1429 2017, p.19; Leith 2006, p.12. It has been reported that in one case a television station was able to show millions of viewers a ShakeMap for an earthquake that had occurred only six minutes earlier (Wald et al. 2002, p.13).
Sipkin, Stuart A.; Filson, John R.; Benz, Harley M.; Wald, David J.; Earle, Paul S. (5 September 2006), "Advanced National Seismic System Delivers Improved Information", EOS Transactions, 87 (36), doi:10.1029/2006EO360003
The Modified Mercalli intensity scale measures the effects of an earthquake at a given location. This is in contrast with the seismic magnitude usually reported for an earthquake.
Seismology is the scientific study of earthquakes and the generation and propagation of elastic waves through the Earth or other planetary bodies. It also includes studies of earthquake environmental effects such as tsunamis as well as diverse seismic sources such as volcanic, tectonic, glacial, fluvial, oceanic microseism, atmospheric, and artificial processes such as explosions and human activities. A related field that uses geology to infer information regarding past earthquakes is paleoseismology. A recording of Earth motion as a function of time, created by a seismograph is called a seismogram. A seismologist is a scientist works in basic or applied seismology.
Earthquakes are caused by movements within the Earth's crust and uppermost mantle. They range from weak events detectable only by seismometers, to sudden and violent events lasting many minutes which have caused some of the greatest disasters in human history. Below, earthquakes are listed by period, region or country, year, magnitude, cost, fatalities, and number of scientific studies.
The Pacific Northwest Seismic Network, or PNSN, collects and studies ground motions from about 400 seismometers in the U.S. states of Oregon and Washington. PNSN monitors volcanic and tectonic activity, gives advice and information to the public and policy makers, and works to mitigate earthquake hazard.
The National Earthquake Information Center is part of the United States Geological Survey (USGS) located on the campus of the Colorado School of Mines in Golden, Colorado. The NEIC has three main missions:
The EarthScope project (2003-2018) was an National Science Foundation (NSF) funded Earth science program using geological and geophysical techniques to explore the structure and evolution of the North American continent and to understand the processes controlling earthquakes and volcanoes. The project had three components: USArray, the Plate Boundary Observatory, and the San Andreas Fault Observatory at Depth. Organizations associated with the project included UNAVCO, the Incorporated Research Institutions for Seismology (IRIS), Stanford University, the United States Geological Survey (USGS) and National Aeronautics and Space Administration (NASA). Several international organizations also contributed to the initiative. EarthScope data are publicly accessible.
USArray was one of the three components of the Earthscope project, the other two components being the Plate Boundary Observatory (PBO) and the San Andreas Fault Observatory at Depth (SAFOD). The components were funded by the National Science Foundation and were constructed, operated, and maintained as a collaborative effort with UNAVCO, the Incorporated Research Institutions for Seismology (IRIS), and Stanford University, with contributions from several other national and international organizations.
Seismic magnitude scales are used to describe the overall strength or "size" of an earthquake. These are distinguished from seismic intensity scales that categorize the intensity or severity of ground shaking (quaking) caused by an earthquake at a given location. Magnitudes are usually determined from measurements of an earthquake's seismic waves as recorded on a seismogram. Magnitude scales vary based on what aspect of the seismic waves are measured and how they are measured. Different magnitude scales are necessary because of differences in earthquakes, the information available, and the purposes for which the magnitudes are used.
An earthquake warning system or earthquake alarm system is a system of accelerometers, seismometers, communication, computers, and alarms that is devised for rapidly notifying adjoining regions of a substantial earthquake once one begins. This is not the same as earthquake prediction, which is currently not capable of producing decisive event warnings.
Susan Elizabeth Hough is a seismologist at the United States Geological Survey in Pasadena, California, and scientist in charge of the office. She has served as an editor and contributor for many journals and is a contributing editor to Geotimes Magazine. She is the author of five books, including Earthshaking Science (Princeton).
The 1965 Puget Sound earthquake occurred at 08:28 AM PDT on April 29 within the Puget Sound region of Washington state. It had a magnitude of 6.7 on the moment magnitude scale and a maximum perceived intensity of VIII (Severe) on the Mercalli intensity scale. It caused the deaths of seven people and about $12.5–28 million in damage. There were no recorded aftershocks.
The United States Geological Survey (USGS), founded as the Geological Survey, is an agency of the U.S. Department of the Interior whose work spans the disciplines of biology, geography, geology, and hydrology. The agency was founded on March 3, 1879, to study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The agency also makes maps of extraterrestrial planets and moons based on data from U.S. space probes.
Recent advances are improving the speed and accuracy of loss estimates immediately after earthquakes so that injured people may be rescued more efficiently. "Casualties" are defined as fatalities and injured people, which are due to damage to occupied buildings. After major and large earthquakes, rescue agencies and civil defense managers rapidly need quantitative estimates of the extent of the potential disaster, at a time when information from the affected area may not yet have reached the outside world. For the injured below the rubble every minute counts. To rapidly provide estimates of the extent of an earthquake disaster is much less of a problem in industrialized than in developing countries. This article focuses on how one can estimate earthquake losses in developing countries in real time.
The European-Mediterranean Seismological Centre is an international, non-governmental and not-for-profit organisation.
ShakeAlert is an earthquake early warning system (EEW) in the United States, developed and operated by the United States Geological Survey (USGS) and its partners. As of 2021, the system issues alerts for the country's West Coast. It is expected that the system will be expanded to other seismically active areas of the United States in the future. ShakeAlert is one of two EEW systems available in the United States, with Google's Android Earthquake Alerts System being the other.
Seismic intensity scales categorize the intensity or severity of ground shaking (quaking) at a given location, such as resulting from an earthquake. They are distinguished from seismic magnitude scales, which measure the magnitude or overall strength of an earthquake, which may, or perhaps may not, cause perceptible shaking.
On May 4, 2018, an earthquake with a magnitude of Mw 6.9 struck Hawaii island in the Hawaii archipelago at around 12:33 p.m. local time. The earthquake's epicenter was near the south flank of Kīlauea, which has been the site of seismic and volcanic activity since late April of that year. According to the United States Geological Survey the quake was related to the new lava outbreaks at the volcano, and it resulted in the Hilina Slump moving about two feet. It was the largest earthquake to affect Hawaii since the 1975 earthquake, which affected the same region, killing two people and injuring another 28.
The 2019 Ridgecrest earthquakes of July 4 and 5 occurred north and northeast of the town of Ridgecrest, California located in Kern County and west of Searles Valley. They included three initial main shocks of Mw magnitudes 6.4, 5.4, and 7.1, and many perceptible aftershocks, mainly within the area of the Naval Air Weapons Station China Lake. Eleven months later, a Mw 5.5 aftershock took place to the east of Ridgecrest. The first main shock occurred on Thursday, July 4 at 10:33 a.m. PDT, approximately 18 km (11.2 mi) ENE of Ridgecrest, and 13 km (8.1 mi) WSW of Trona, on a previously unnoticed NE-SW trending fault where it intersects the NW-SE trending Little Lake Fault Zone. This quake was preceded by several smaller earthquakes, and was followed by more than 1,400 detected aftershocks. The M 5.4 and M 7.1 quakes struck on Friday, July 5 at 4:08 a.m. and 8:19 p.m. PDT approximately 10 km (6 miles) to the northwest. The latter, now considered the mainshock, was the most powerful earthquake to occur in the state in 20 years. Subsequent aftershocks extended approximately 50 km (~30 miles) along the Little Lake Fault Zone.
David Jay Wald is a seismologist with the U.S. Geological Survey (USGS) at the National Earthquake Information Center (NEIC) in Golden, Colorado. He is an affiliated faculty member at the Colorado School of Mines, and served as the editor-in-chief of the Earthquake Engineering Research Institute's (EERI) journal, Earthquake Spectra, from 2018–2022. He also served on the Southern California Earthquake Center Science Planning Committee, 2014–2020.
Kate E. Allstadt is a geologist and seismologist employed by the U.S. Geological Survey (USGS) who works out of Golden, Colorado. She is a self-described "present-day geologist" for her interest in connections between geology of the Pacific Northwest and the people in its local communities. She is a published expert on the 2014 Oso landslide.
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