Thursday, October 18, 2007
For six months in 1954, central Nevada was violently shaken by a series of earthquakes that literally changed the shape of the land. Between July 6 and December 16, six quakes shook west central Nevada and eastern California.
The biggest of the temblors, which occurred a little after 3 a.m. on December 16, registered 7.3 on the Richter Scale (for comparison, the San Francisco earthquake of 1906 was 7.8). It was felt over an area of more than 200,000 square miles.
The epicenter of the quake was seven miles west of U.S. 50, at a spot east of Fairview Peak (about 40 miles east of Fallon). Four minutes later, the area was rocked again by an aftershock that measured 6.9.
The effect of the twin quakes was spectacular surface ruptures and cracks in the nearby valley as well as significant shifts in elevation. Nearly 50 miles of faulting was exposed on Fairview Peak and in the Dixie Valley and Clan Alpine Range to the northwest.
Scientists’ estimate that in some places the mountains rose more than 20 feet relative to the surrounding valleys (although rises of six-feet were more common).
Fortunately, the area most affected by the quakes was sparsely populated so property damage was minimal and no one was injured. U.S. 50 experienced some cracking and buckling and, in one fifty-foot section, the roadway dropped more than five feet.
In Fallon, the closest community of any size, there were a few cracked and toppled chimneys. At the Newlands Project, the series of canals and ditches that transport water to the Lahontan Reservoir, there were reports of several breaks and leaks.
Sacramento, located about 200 miles west, the shock wave apparently caused an estimated $20,000 in damage to a large underground water tank at the city’s filtration plant.
Today, it’s still possible to see traces of the tremendous geological shifting that occurred during the 1954 quakes in the vicinity of Fairview Peak and Dixie Valley.
A road sign on U.S. 50, east of Frenchman’s Flat, points you south to a dirt road that leads to an interpretive display describing the quakes. In fact, if you walk a quarter-mile west of the interpretive sign you can find the exposed fault line.
If you continue on the dirt road, you can see additional fault scarps (places where the ground has been pushed higher than the surrounding area) as well as other faults, which resemble crude trenches dug in the hillside.
The interpretive sign explains that earthquakes basically occur when pressure builds under the earth’s crust and is suddenly released. Portions of the crust will bend or, when the stress exceeds the strength of the surface, break and snap into a new position.
As great as the Fairview/Dixie Valley quakes were, they weren’t the biggest in Nevada’s history. The U.S. Geological Service ranks Nevada as among the most seismically active states.
The earliest recorded earthquake in the state occurred in 1851 near Pyramid Lake. According to later newspaper articles, great cracks opened near the lake and water spouted 100 feet into the air.
The strongest recorded earthquake happened in October 1915, when three temblors in a seven-hour period rattled most of northern Nevada. The biggest shock, with a magnitude of 7.75, struck the Pleasant Valley (north of Winnemucca), and caused damage to homes in Lovelock and Winnemucca. More than 100 aftershocks followed during the next few weeks.
An earthquake of about the same magnitude as that of Fairview Peak (7.3) occurred near Cedar Mountain (near Gabbs) on December 20, 1932. Two cabins were reported destroyed by the quake and a handful of chimneys collapsed on homes in Mina, Luning, and Hawthorne.
For more information about earthquakes in Nevada, including tips on how to cope with one, check out the University of Nevada Reno Seismological Laboratory web site at www. seismo.unr.edu.