Earthquakes in the United States
Earthquakes are among the most frightening and devastating of natural events—they strike without warning, allowing no time for preparation or evacuation. Nationwide, at least 39 states are considered at risk from moderate to great earthquakes. Earthquakes have struck many areas of the United States, including Alaska and the Central and East Coast states. Note some of the following examples including two recent earthquakes:
- 1994 Northridge Earthquake
The January 17, 1994 Northridge, California earthquake is just one example of the devastation caused by earthquakes. The Northridge earthquake resulted in over 60 deaths, more than 5,000 injuries, and over 25,000 people left homeless, and it occurred in the early morning of a holiday. Direct economic losses from the Northridge earthquake are estimated at about $25 billion. But the Northridge earthquake was not even the big one! It was a large (magnitude 6.7) but not a great earthquake, of relatively short duration (the main shock lasting roughly 15 seconds). By contrast, the 1906 San Francisco earthquake was estimated as a magnitude 8.3 event, lasting 45 seconds. The 1964 Alaska earthquake (magnitude 8.4) lasted over 3 minutes.
- 2002 Denali Eathquake
On November 3, 2002, the magnitude 7.9 Denali earthquake rocked Alaska. This was one of the largest recorded earthquakes in our Nation's history, causing countless landslides and road closures, but minimal structural damage and amazingly few injuries and no deaths. Although the remote location of the earthquake helped ensure that it was not more devastating, advanced seismic monitoring from the United States Geological Survey (USGS), long-term research, and a commitment to earthquake preparedness and mitigation played key roles.
- 2003 San Simeon Earthquake
The magnitude 6.5 San Simeon earthquake occurred on December 22, 2003, with an epicenter near the Pacific coast in central California. Although it did not rupture the surface, the earthquake triggered landslides and caused strong shaking. The worst damage occurred in Paso Robles, 24 miles southeast of the epicenter, where numerous older buildings were damaged and one building collapsed, killing two people. In response to the San Simeon earthquake, the USGS produced a ShakeMap within 9 minutes of the event. The ShakeMap served as the basis for loss estimation by the California Office of Emergency Services using HAZUS, or Hazards U.S., within 1 hour.
Larger events such as these can be expected in the United States, and they will not be confined solely to the West Coast region. In fact, two of the most severe earthquakes in U.S. history occurred east of the Rockies: one in Charleston, South Carolina, in 1886 and the other a series of three shocks centered near New Madrid, Missouri, in 1811-12. Measuring an estimated 8.5 in magnitude, the New Madrid earthquake sent shock waves as far west as the Rocky Mountains and as far east as Washington, D.C. and Boston.
Last Modified: Wednesday, 12-Apr-2006 15:43:16 EDT