Wednesday, 12 March 2014

Hansel Valley earthquake

80 years ago, on the morning of March 12, 1934, Kelton was hit by the most powerful earthquake ever recorded in Utah. At a magnitude of 6.6 and an intensity of VIII, the Hansel Valley quake and its aftershocks might have been devastating in a densely-populated area, but only two people were killed.

Abandoned foundation in Kelton, Utah

This earthquake occurred in the valley, a sparsely populated area.

Property damage was limited mainly to downed chimneys and cracked walls in poorly constructed brick buildings. Chimneys were downed in several towns in the county, including Hooper, Kelton, Kosmo, Locomotive Springs, Monument, and Snowville. Large rockslides occurred at Aragonite, Lakeside, Monument Rock, and Snowville. An outstanding feature of this earthquake was the large quantity of water emitted from the craterlets and fissures that developed in the area.

Kelton Sign

Most of the ground cracks that formed in the epicentral area occurred in poorly consolidated rocks on the salt flats. These cracks were traced for a distance of more than 8 kilometers. Four distinct fractures, about 1 kilometer apart, developed across a road about 5 kilometers north of Kosmo. The vertical displacement along the fractures ranged from about 7.5 to 25.5 cm. Precise leveling surveys later revealed that areas of land sank as much as 39 cm. Horizontal displacement was not observed.

Landscape of the Box Elder County

Many springs formed in the epicentral area. Most of them developed along well-defined fractures in the salt flats where water flowed along the fissure. Notable exceptions, however, were the springs that formed in Monument Rock where water flowed at individual centers and formed mud cones. In places, large holes developed around the springs by the caving of the soft material through which the water flowed. Two such holes on the salt flats northeast of Monument Rock ranged in diameter from 2.5 to 3 meters, and one was 11 meters deep.

Also felt in Idaho, Montana, Nevada, and Wyoming.

Today Kelton is a ghost town.