Earthquake early warning in the United States
- a one page summary.
Earthquake early warning can provide a few seconds to tens of seconds warning prior to ground shaking during an earthquake.
ElarmS, short for Earthquake Alarms Systems, is a methodology designed to provide warnings in California and other earthquake prone regions around the world. The warning messages provided by ElarmS can be used to reduce the damage, costs and casualties in an earthquake.
ElarmS takes the form of a suite of algorithms designed to (1) rapidly detect the initiation of an earthquake, (2) determine the size (magnitude) and location of the event, (3) predict the peak ground motion expected in the region around the event, and (4) issue a warning to people in locations that may expect significant ground motion.
The algorithms use data from regional broadband seismic networks.
ElarmS is currently being tested by the
as part of the realtime seismic system in California. This pre-prototype test will allow assessment of the likely timeliness and accuracy of warnings if early warning is implemented for general use in California.
ElarmS has also been tested offline using data from Japan, Taiwan, Alaska, the Pacific Northwest and California.
Earthquake early warning systems have been expanding rapidly around the world. There are currently warning systems in Japan, Taiwan, Mexico, Turkey and Romania.
Earthquakes (red) and faults (black) in California
Active (blue) and developmental (green) earthquake early warning systems around the world.