Fallon-Stillwater Earthquake – Nevada – July 6, 1954

The area hit, Fallon-Stillwater, is about one hundred miles southeast of Reno, largely deserted in 1954 so there were no casualties and damage was mainly to buildings.

In Fallon, the town nearest the epicenter of the magnitude 6.8 Fallon- Stillwater, Nevada, Earthquake, several old and poorly built concrete-block structures and un-reinforced brick structures were damaged severely, and many brick chimneys fell. Several people were injured at the Naval Auxiliary Air Station, about five miles southeast of Fallon, when the shock knocked heavy steel lockers on to 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 heaviest 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 three feet for a distance of a thousand feet and lurched about three feet horizontally toward a canal. In the Lone Tree and Stillwater areas, canal banks settled as much as three feet, and bottoms of canals were raised as much as two feet. The quake was felt in California, Idaho, Oregon, and Utah.

The state of Nevada is earthquake country. It lies within the Basin and Range structural and geomorphic province, a region that is actively extending, or being pulled apart in roughly a northwest-southeast direction. The Basin and Range province is riddled with active faults and is one of the most seismically active regions in the United States. Nevada, along with California, has been subject to many large earthquakes in the last 150 years.

The average occurrence of earthquakes of magnitude 6 and greater in Nevada is about ten years. The average occurrence of earthquakes of magnitude 7 and greater that have strongly shaken the state is about twenty-seven years. The range in time between earthquakes of magnitude 7 or greater is seventeen to forty-four years, and the last one occurred thirty-five years ago.

On December 27, 1869, an earthquake of magnitude 6.7 shook down walls in Virginia City and Gold Hill, and is referred to as the Olinghouse earthquake, after the mining district northwest of Wadsworth where the earthquake is thought to have originated. The largest earthquake in Nevada’s history, a magnitude 7.6 one on October 3, 1915, was centered in Pleasant Valley, south of Winnemucca.

This earthquake broke the surface in four different places over a distance of thirty-seven miles. The largest offset of the ground was nineteen feet of vertical movement. In 1932, a magnitude 7.2 earthquake originated in the Gabbs area and was felt throughout Nevada and beyond, over an area of 500,000 square miles. This earthquake involved several faults failing in sequence.

Four earthquakes occurred in 1954 that caused damage to buildings in Fallon and ruptured the ground in a spectacular fashion in Dixie Valley and near Fairview Peak, 30–35 miles east of Fallon. The July and August 1954 earthquakes occurred along the same fault at Rainbow Mountain, east of Fallon, and had magnitudes of 6.6 and 7.0. On December 16, 1954, two large earthquakes of magnitude 7.2 and 6.8 occurred only four minutes apart at Fairview Peak and Dixie Valley.

Faulting of the surface occurred discontinuously from northern Gabbs Valley to Dixie Valley, a distance of sixty-three miles. The largest fault scarp was about twenty-three feet high, near Fairview Peak. Faulting of the ground surface is commonly associated with large earthquakes of magnitude 5.5 or greater. One major goal of earthquake hazard mitigation is to avoid locating buildings or other important structures across such faults.

It has been years since the last large earthquake in Nevada, in 1954, and many Nevadans don’t appreciate how high the earthquake potential is. We cannot prevent earthquakes but many steps can be taken to minimize or eliminate their potential hazards. Mitigation measures include building with sound lateral or shear support, anchoring objects inside a home that might topple or fall and injure someone, and being prepared to respond to an earthquake, no matter where you are.

For the past fifteen years the Nevada Bureau of Mines and Geology has had an earthquake hazard program designed to provide the public with information to understand, evaluate, and mitigate earthquake hazards. The University of Nevada Seismological Laboratory maintains a seismographic network in western Nevada and records, analyzes, and catalogs earthquakes in Nevada and eastern California.

It has also published an earthquake epicenter map of Nevada, and a number of fault and related hazard maps which are available for urban areas in Nevada including the Carson City, Las Vegas, and Reno areas at scales of 1:24,000. Regional maps are available at a scale of 1:250,000. Other specific seismic hazard investigations include studies of the Dixie Valley fault, studies of the Quaternary tectonics and faulting at the potential site for high-level nuclear waste storage at Yucca Mountain, and research on the large Basin and Range earthquakes.

If people are aware of the tectonic forces responsible for the spectacular landscape of Nevada, and spend a little time preparing for the earthquakes that these forces can produce, we can live safely with the earthquakes that will eventually occur.

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