Pleasant Valley Earthquake – Nevada – October 3, 1915

Pleasant Valley was thinly populated and the main impact of the quake was geological, creating a twenty-mile scarp at the base of the Sonoma Mountains.

The largest earthquake in Nevada’s history up to 1915 occurred on October 3, 1915, and was centered in Pleasant Valley, south of Winnemucca. This earthquake had a magnitude of 7.1 and it was followed by several aftershocks that disturbed a large part of northern Nevada. It destroyed or seriously damaged many adobe houses in Pleasant Valley. Most of the damage was confined to the towns of Kennedy, Lovelock, and Winnemucca.

The earthquake was felt over a very wide area, from Baker, Oregon, to San Diego, California, and from the Pacific coast to beyond Salt Lake City, Utah. A scarp four to fourteen feet high and more than twenty miles long was formed parallel to the base of the Sonoma Mountains. It broke the surface in four different places for a distance of thirty-seven miles. The largest offset of the ground was nineteen feet of vertical movement.

This earthquake occurred along a fault on the eastern side of Pleasant Valley, about forty miles southeast of Winnemucca, in the north-central part of Nevada. This location of the epicenter was almost uninhabited and, therefore, property damage was less than might have been expected. Damage was confined mainly to an area within forty-five miles of the Pleasant Valley Fault.

The combined length of the scarps was thirty-five miles, the average vertical displacement six feet, and the maximum displacement eighteen feet. Several northwest-striking segments of the scarps had a right-lateral component of displacement, generally less than three feet.

At Kennedy, two adobe houses were destroyed, mine tunnels collapsed, and concrete mine foundations were cracked. At Winnemucca, adobe buildings generally were damaged, and several multistory brick buildings lost their coping and parts of upper walls; many chimneys were demolished above the rooflines. In addition, water tanks were thrown down at Battle Mountain, Kodiak, Lovelock, and Parran.

Damage occurred on several ranches at the southern end of Pleasant Valley. An adobe house was shaken down, a masonry chicken house and a hog pen were destroyed, and houses were displaced from their foundations. There was a large increase in the flow of springs and streams throughout northern Nevada and cracks formed in unconsolidated materials for considerable distances.