February 28, 2003
The magnitude 7.9 earthquake that hit central Alaska on Nov. 3, 2002 was the world’s biggest in 2002, and the largest to hit the United States since 1996 when another 7.9 quake hit Alaska’s Andreanof Islands.
In 2002, according to the U.S. Geological Survey, there were 85 “significant” earthquakes that killed 1,711 people around the world. So-called “significant” earthquakes have a magnitude of 6.5 or greater or cause fatalities, injuries or substantial damage. A magnitude 6.1 earthquake in Afghanistan was the deadliest of 2002, killing at least 1,000 people. There were 13 major quakes (magnitude 7.0-7.9) in 2002 and no great earthquakes of magnitude 8 or higher.
The USGS locates about 50 earthquakes each day or almost 20,000 a year. On average, there are 18 major earthquakes and one great earthquake each year worldwide. Several million earthquakes occur in the world each year, but many go undetected because they occur in remote areas or have very small magnitudes. In the U.S., earthquakes pose significant risk to 75 million Americans in 39 states, according to the USGS.
The Alaska quake caused $20 million in damage and temporarily suspended operation of the Trans-Alaska Pipeline. As a result of the quake, wells in Louisiana’s Lake Pontchartrain sloshed about, and wells in Washington, Idaho, Louisiana, Oklahoma, Missouri, Wisconsin and Pennsylvania produced muddy water as a result of the Alaska temblor.
The most noteworthy aspect of this earthquake was that the Trans-Alaska Pipeline did not rupture. USGS scientists helped insure that the Trans-Alaska Pipeline was designed and built to withstand the effects of a magnitude 8.0 earthquake with up to 20 feet of movement at the pipeline, the agency noted.
Working to improve earthquake monitoring and reporting capabilities, the USGS is beefing up the Advanced National Seismic System. In the past three years the USGS has installed approximately 300 new earthquake-monitoring instruments in vulnerable urban areas including San Francisco, Seattle, Salt Lake City, Anchorage, Reno, Las Vegas and Memphis. Full implementation of ANSS will result in 6,000 new instruments on the ground and in structures. Once in place, the ANSS will provide emergency response personnel with real-time (within 5-10 minutes) information on the intensity and distribution of ground-shaking that can be used to guide response efforts.
Information on building “shaking” will equip engineers with the data they need to improve building future designs.