Historic Earthquakes

Wood River
1947 Oct 16 02:09:52.5 UTC
Magnitude 7.2

This major earthquake centered southeast of Nenana on the Salcha River fault. Small fissures formed in the ground near the Nenana Airport, southwest of Fairbanks. Streets "upheaved" at Nenana in several places, and several long cracks formed in the ground. Cracks in river mud and ice occurred from Shaw Creek on Richardson Highway to the headwaters of the Kantishna and Tolavana Rivers. Cracks 56 centimeters wide, as much as 30 centimeters deep, and several meters long were reported about 24 kilometers below Chena Bluffs on the Tanana River. A few pressure ridges were observed where large, frozen blocks came together.

Alaska Railroad officials reported that rails were bent between Julius , Nenana, and Browne, and that some changes were observed in the elevation of the roadbed. Landslides occurred on the Richardson Highway, and rockslides were observed between Fairbanks and Nenana on the Tanana River.

In Fairbanks, merchandise in stores was damaged heavily, many windows were broken, and a powerline short-circuit occurred near the University of Alaska. Changes in the flow of water in several wells were reported both at Fairbanks and Nenana. Trees and poles were shaken violently. At the town of Clear, south of Nenana, some prefabricated buildings were damaged.

The felt area is rather well defined to the south and west but is uncertain to the north and east because of sparse population. The earthquake was felt over most of central and southern Alaska and at two places in the Yukon Territory of Canada, an area within a radius of about 500 kilometers of the epicenter. This earthquake series consisted of more than 200 foreshocks and aftershocks. The strongest aftershock occurred on October 20.

Abridged from Seismicity of the United States, 1568-1989 (Revised), by Carl W. Stover and Jerry L. Coffman, U.S. Geological Survey Professional Paper 1527, United States Government Printing Office, Washington: 1993.