1949 Olympia Earthquake

USGS Open-File Report 86-253 calls the April 13, 1949, Olympia earthquake a magnitude 7.1 event between Olympia and Tacoma. It lists a focal depth of about 70 kilometers (42 miles). The shock was felt over some 390,000 square kilometers and caused $25 million in damage in actual dollars. Nearly all tall buildings in Olympia were damaged. Eight people were killed.

The USGS preferred-magnitudes catalog lists the origin as April 13, 1949, 19:55, Olympia, Washington, at 47.1° N, 122.7° W, magnitude 7.1 ML. USGS Open-File Report 91-441r gives an instrumentally determined depth of 54 kilometers for the 1949 south Puget Sound earthquake (Ms = 7.1) and notes that no aftershocks were felt or recorded above about magnitude 4.5.

USGS Open-File Report 99-311 places the 1949 M7.1 earthquake near Olympia at 54 kilometers depth inside the subducting Juan de Fuca plate, with the 1965 M6.5 event near Tacoma at 60 kilometers. Together with the 1965 shock, USGS says the two earthquakes caused most of the major historic earthquake damage in the Pacific Northwest. The sources below are U.S. Geological Survey reports.