earthquake information on the web

After an earthquake, knowing more about what just happened can reduce fears and help you understand what to expect next. Online earthquake information products include:

Location and magnitude of recent earthquakes

Within 1 to 2 minutes of an earthquake, its location and magnitude are available at several Web sites, including
http://earthquake.usgs.gov/ and
http://quake.usgs.gov/recenteqs/latest.htm

"ShakeMap"

Within 5 to 10 minutes of most felt earthquakes (magnitude 3.5 and greater) in the Bay Area, a "ShakeMap" is posted on the Web. This map shows the range of shaking intensities across a region. Every quake has only a single magnitude, but it produces a range of shaking intensity values over the area in which it is felt.

ShakeMaps use data from seismic instruments to provide a rapid picture of where the strongest shaking occurred. These maps help to identify areas where a quake's impact is greatest and are used by emergency managers to speed disaster response. ShakeMaps are available at
http://www.cisn.org/shakemap.html or
http://earthquake.usgs.gov/shakemap/

"Did You Feel It?" -- Tell us what you felt!

Personal experiences of the effects of an earthquake are very valuable to scientists. When you have felt a quake, please report your observations by using a quick survey found on the U.S. Geological Survey "Did You Feel It?" Web site at
http://pasadena.wr.usgs.gov/shake/ca/

When you fill out this online survey, your observations of actual damage and shaking are combined with those of thousands of other people. The quake's shaking intensities, derived from these observations, are displayed by ZIP code on a "Community Internet Intensity Map."

Who monitors California's earthquakes?

Earthquake monitoring for California is done by the California Integrated Seismic Network (CISN), a partnership among the U.S. Geological Survey (USGS), University of California Berkeley, Caltech, the California Geological Survey, and the Governor's Office of Emergency Services. CISN is part of a USGS national seismic-monitoring program called the Advanced National Seismic System (ANSS).

For more information go to:
http://www.cisn.org/
http://www.anss.org/