The Rat Islands are part of the Aleutian Islands off of Alaska. According to the Alaska Earthquake Information Center, “Large earthquakes in the Aleutian arc occur on the convergent boundary between the Pacific and North American crustal plates. This region, where the two plates are being forced directly into one another, is one of the world’s most active seismic zones. Over one hundred earthquakes of magnitude seven or larger have occurred along this boundary in the past hundred years.”[1]

[1] Ratchkovski, N. “February 4, 1965 Rat Islands Earthquake.” May 2005. Alaska Earthquake Information Center (AEIC). Retrieved September 1, 2011.