Anchorage Area Fault May Be Due for 6 or 7 Magnitude Quake

A new study by the U.S. Geological Survey (USGS) shows that the Castle Mountain fault in south-central Alaska may be ready to produce a strong magnitude 6 to 7 earthquake. Peter Haeussler, the principal investigator in the study, said his research demonstrated that major earthquakes occurred on this fault on average every 700 years or so in the last 2,700 years, and that the last significant earthquake along the fault occurred about 650 years ago. The Castle Mountain fault is the only active fault that comes to the earth’s surface in the Anchorage region, and the eastern part of the fault produced light to moderate magnitude 5.7 and 4.6 earthquakes in 1983 and 1996.