Satellite view over the Chugach Mountains and Anchorage, Alaska

Recent Earthquakes

Alaska Volcano Observatory
USGS/AVO Don Richter Memorial Volcano Seminar Series

Crisis Room, Anchorage, AlaskaAlaska is one of the most geologically active areas in the world. The surface of the earth has numerous large plates, sections of the earths crust that move about the surface, crashing into each other, grinding past each other, and overrunning one another. Alaska is home to one of the most active plate boundaries on the planet, where the Pacific Plate is being forced under (or subducting under) the North American Plate at rates greater than 7 cm/year (just under 3 inches/year). Though this process forms much of the magnificent mountain ranges and peaks in Alaska.

Trace of the Denali Fault line from the Denali Fault Earthquake running up the north side of the Canwell Glacier about 10 miles east of the Richardson Highway.  Peter Haeussler, USGS.The process also brings to Alaska earthquakes and volcanoes. Alaska is the most seismically active state in the U.S. by a large margin and one of the most active areas in the world. Three of the six largest earthquakes ever recorded world-wide occurred in Alaska as did seven of the 10 largest in the U.S.

Redoubt Volcano in Southcentral Alaska 1989Similarly, the plate movements produce one of the most active volcanic arcs in the world. Roughly 10% of the worlds active volcanoes are in Alaska and on average, 1-2 erupt each year. The largest eruption in the 20th century was at Katmai on the Alaska Peninsula in 1912. Though many of Alaska's volcanoes are in the remote Aleutians, volcanic ash resulting from eruptions any of these volcanoes pose a significant hazard to the aviation industry, including the wide-body jets flying the North Pacific air routes between North America and Asia.

The Hazards Office of the Alaska Science Center is the focal point for U.S. Geological Survey earthquake and volcano work in Alaska. Scientists in the Hazards Office work closely with USGS scientists outside Alaska as members of national teams striving to understand better seismic and volcanic processes in order to minimize loss of life and property resulting from their inevitable occurrence. In Alaska, the Hazards Office also works closely with partners at the University Of Alaska Fairbanks Geophysical Institute, the State of Alaska Division of Geological and Geophysical Surveys, and the West Coast & Alaska Tsunami Warning Center to fulfill the USGS's congressionally-mandated responsibility to issue warnings of earthquake- and volcano-related hazards. Congress authorized the U.S. Geological Survey to issue warnings of geologic-related hazards, including earthquakes and volcanoes. (Public Law 93-288, Federal Register vol. 42, No 70, page 19292, April 12, 1977). Through formal partnerships such as the Alaska Volcano Observatory and the Alaska Earthquake Information Center, work by the partners agencies are presented to the public as a common voice.


U.S. Department of the Interior
U.S. Geological Survey
Alaska Science Center

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Last updated: October 5, 2005
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