Historic Earthquakes

Fallon-Stillwater area, Nevada
1954 July 06 UTC
Magnitude 6.6

In Fallon, the town nearest the epicenter, several old and poorly built concrete-block structures and unreinforced brick structures were damaged severely, and many brick chimneys fell. Several people were injured at the Naval Auxiliary Air Station, about 8 km southeast of Fallon, when the shock knocked heavy steel lockers onto them. Two areas outside Fallon that also sustained damage were the Lone Tree district to the south and the Stillwater district to the east. Ground motion and surface breakage were heavier in Stillwater.

Canals and drainage systems of the Newlands Reclamation Project near Fallon were damaged extensively. Many box-type culverts were damaged or collapsed. Failure of the Coleman Diversion Dam cut off irrigation water to most of the project.

Paved highways in the Fallon-Stillwater areas settled, cracked, and buckled in several places. One of the largest ground movements occurred in the Lone Tree area. One road dropped about 0.9 meters for a distance of several hundred meters and lurched about 0.9 meters horizontally toward a canal. In the Lone Tree and Stillwater areas, canal banks settled as much as 0.9 meters, and bottoms of canals were raised as much as 0.6 meters.

The main zone of ground fractures was observed on the east edge of Rainbow Mountain in the Stillwater Range, about 24 km southeast of Fallon. This earthquake and the large shock on Aug. 24 resulted in surface evidence of faulting for about 40 km. This break is referred to as the Rainbow Mountain fault. Vertical displacement was evident along about two-thirds of the fault; the west side uplifted everywhere with respect to the east side. Scarps as high as 30 cm or more formed, and small grabens developed in places. Horizontal displacement was not found. The quake was also felt in California, Idaho, Oregon, and Utah.

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.