About the Realtime Earthquake Maps

Frequently Asked Questions (FAQ) about the Current Earthquakes information

USGS Earthquake Magnitude Policy

Realtime Earthquakes Data Sources & Contributing Networks

US, International, and offshore regions:

Map Information and Data Sources

Map Software

Generic Mapping Tool (GMT) by Wessel and Smith

Topographic Data

This data was acquired from the Scripps Institute of Oceanography Satellite Geodesy website at http://topex.ucsd.edu/marine_topo/mar_topo.html. The data in its original form is 1 minute topographical data for the entire globe. To meet the requirements of showing topography/bathymetry at the two degree scale, this data was broken into regions of Alaska, Hawaii, Puerto Rico, and the conterminous U.S. These regions were then re-sampled to an appropriate scale in order to show regional detail.

Plate Boundary Data

This data was acquired from the Peter Bird Plate Boundary Dataset. Information about this data can be found at: http://peterbird.name/publications/2003_PB2002/2003_PB2002.htm

Water Data

The river and lakes data for these maps came from GMT and its pre-built dataset. The detailed shoreline data that is present in coastal maps was acquired from NOAA’s Coastal Geospatial Data Project. More information can be found at: http://coastalgeospatial.noaa.gov/gis_files/shoreline/shoreline_data_dictionary.html

State and International Boundaries

Generic Mapping Tool (GMT) by Wessel and Smith

Placename Data:

The placenames were derived from US Census data, such as from http://www.census.gov/geo/www/gazetteer/places2k.html. Places were selected based on minimum population values that were specified for each particular region. If there are too many places on any map, a separation distance algorithm was used to limit the number of places that appear on the map. If no places appeared on the map, a lower population threshold was used to plot smaller places. For Mexico, Canada, and the Caribbean, other census files were used. The exact source of those files isn't precisely known.
Minimum Place Population:
Alaska 10° - 50
Alaska 2° - 50
Hawaii 10° - 16,000
Hawaii 2° - 16,000
Puerto Rico 10° - 16,000
Puerto Rico 2° - 16,000
U.S. 10° - 64,000
U.S. 2° - 16,000

Note: A place with a population of greater than 350,000 is always plotted regardless of separation distance.

Faults

The data used for these features was acquired from the Quaternary Fault and Fold Database for the United States.

Known hazardous faults and fault zones in California and Nevada

The known active fault segments in California and Nevada can be seen in Figure 25 of USGS Open-File Report 96-532: National Seismic Hazard Maps, June 1996: Documentation" by Arthur Frankel, Charles Mueller, Theodore Barnhard, David Perkins, E.V. Leyendecker, Nancy Dickman, Stanley Hanson, and Margaret Hopper.

For northern California, the potential sources of earthquakes larger than magnitude 6 are documented in Open-File Report 96-705 by the Working Group on Northern California Earthquake Potential (chaired by Jim Lienkaemper).

For the state as a whole, see "Probabilistic seismic hazard assessment for the State of California" by Petersen, M. D., Bryant, W.A., Cramer, C.H., Cao, T., Reichle, M.S., Frankel, A.D., Lienkaemper, J.J., McCrory, P.A., and Schwartz, D.P, 1996 (California Division of Mines and Geology Open-File Report 96-08; [published jointly as] U.S. Geological Survey Open-File Report 96-706).

The faults and fault zones described in these reports are known to have been active in the last 2 million years and are thought to pose a measurable hazard.

For California the faults on the individual zoomed-in and special maps come from the three categories of faults believed to have been active in the last 700,000 years shown on the "Preliminary Fault Activity Map of California" by C.W. Jennings (1992, California Division of Mines and Geology Open-File Report 92-03). This map has been superseded by Jennings, C.W., 1994, Fault activity map of California and adjacent areas, with locations and ages of recent volcanic eruptions: California Division of Mines and Geology, Geologic Data Map No. 6, map scale 1:750,000.

For Nevada the faults on the individual zoomed-in and special maps come from USGS Open-File Report 96-532 mentioned above.

For more information on files and images discussed above visit the1996 Documentation Page

Highways and Roads

Interstate Highway data is from the National Atlas of the United States.

Network Contacts

National Earthquake Information Center (NEIC)

U.S. Geological Survey
National Earthquake Information Center
Box 25046, DFC, MS 967
Denver, Colorado 80225

Earthquake Information Line: 303-273-8516
(Recorded information on earthquakes occurring during the previous 24 hours.)
Operations: 303-273-8500
Fax: 303-273-8450
Web Page: http://earthquake.usgs.gov/regional/neic/
E-mail: sedas@neis.cr.usgs.gov

Alaska Earthquake Information Center (AEIC)

Alaska Earthquake Information Center (AEIC)
Geophysical Institute
University of Alaska Fairbanks
903 Koyukuk Drive
Fairbanks, AK 99775-7320

Voice: 907-474-7320
Fax: 907-474-7125
Web Page: http://www.aeic.alaska.edu/
E-mail: webmaster@giseis.akaska.edu

West Coast and Alaska Tsunami Warning Center/NOAA/NWS

West Coast and Alaska Tsunami Warning Center/NOAA/NWS
910 S. Felton St.
Palmer, AK 99645

Web Page: http://wcatwc.arh.noaa.gov/
E-mail: wcatwc@wcatwc.gov

Cooperative New Madrid Seismic Network

Center for Earthquake Research and Information
Campus Box 526590
The University of Memphis
Memphis, TN 38152

Voice: 901-678-2007
Fax: 901-678-4734
Web Page: http://folkworm.ceri.memphis.edu/
E-mail: withers@ceri.memphis.edu

Inter-Mountain West Seismic Networks

Earthquake Studies Office
Montana Bureau of Mines and Geology
1300 West Park Street
Butte, MT 59701-8997

Voice: 406-496-4332
Fax: 406-496-4451
Web Page: http://mbmgquake.mtech.edu/
E-mail: mstickney@mtech.edu

Nevada Seismological Laboratory
University of Nevada, Reno
Reno, Nevada

Voice: 775-784-4975
Fax: 775-784-4165
Web Page: http://www.seismo.unr.edu/

University of Utah Seismograph Stations
135 South 1460 East
Salt Lake City, Utah 84112-0111

Voice: 801-581-6274
Fax: 801-585-5585
Web Page: http://www.seis.utah.edu/
E-mail: webmaster@seis.utah.edu

Hawaiian Volcano Observatory Network

U.S. Geological Survey
Hawaiian Volcano Observatory
P O Box 51
Hawaii National Park, Hawaii 96718

Voice: 808-967-7328
Fax: 808-967-8890
Web Page: http://hvo.wr.usgs.gov/
Web Page: http://elsei.wr.usgs.gov/results/seismic/recenteqs/
E-mail: hvowebmaster@hvo.wr.usgs.gov

Northeast

Lamont-Doherty Cooperative Seismographic Network (LCSN)
Lamont-Doherty Earth Observatory of Columbia University
Palisades, NY 10964

Voice: 845-365-8365
Fax: 845-365-8150
Web Page: http://www.ldeo.columbia.edu/LCSN/
E-mail: jha@ldeo.columbia.edu

Weston Observatory
Department of Geology and Geophysics, Boston College
381 Concord Road Weston, MA 02493-1340

Voice: 617-552-8300
Fax: 617-552-8388
Web Page: http://www.bc.edu/bc_org/avp/cas/wesobs/
E-mail: weston.observatory@bc.edu

Massachusetts Institute of Technology (MIT)

Web Page: http://eaps.mit.edu/erl/

Northern California Seismic Network

U.S. Geological Survey
Seismology Section
345 Middlefield Road - MS 977
Menlo Park, CA 94025

Earthquake Info: 650-329-4025
Voice: 650-329-4085
Fax: 650-329-5163
Web Page: http://quake.wr.usgs.gov/
E-mail: ncsn@andreas.wr.usgs.gov

U.C. Berkeley Seismological Laboratory
207 McCone Hall
U.C. Berkeley
Berkeley, CA 94720-4760

Earthquake Info: 510-642-2160
Voice: 510-642-3977
Fax: 510-643-5811
Web Page: http://www.seismo.berkeley.edu/
E-mail: www@seismo.berkeley.edu

Pacific Northwest Seismic Network

Univ. of Washington, Dept. of Earth and Space Sciences
Box 351310
Seattle, WA 98195-1310

Earthquake Info: 206-543-7010
Voice: 206-685-8180 (lab) or 206-543-1190 (department)
Fax: 206-543-0489
Web Page: http://www.ess.washington.edu/SEIS/PNSN/welcome.html
E-mail: seis_web@ess.washington.edu

Puerto Rico Seismic Network

Puerto Rico Seismic Network
Department of Geology
University of Puerto Rico at Mayagüez
PO Box 9017
Mayagüez, PR 00681-9017

Voice: 787-833-8433
Fax: 787-265-1684
Web Page: http://redsismica.uprm.edu/english/
E-mail: staff@redsismica.uprm.edu

Southern California Seismic Network

Southern California Seismic Network
U.S. Geological Survey - Caltech Seismological Laboratory
Pasadena, California

EQ Info: 626/395-6977
Voice: 626/583-7823 or 626/395-6919
Fax: 626/583-7827
Web Page: http://earthquake.usgs.gov/regional/sca/
Web Page: http://www.seismolab.caltech.edu/
Email: lisa@usgs.gov

About the Realtime Earthquake Maps

Realtime Earthquakes Data Sources & Contributing Networks

US, International, and offshore regions:

Alaska:

Central and Southeastern US data:

Hawaiian data:

Nevada data:

Northeast data:

Northern California data:

Pacific Northwest data:

Puerto Rico data:

Southern California data:

Utah and Yellowstone data:

All members of the ...