Wednesday, June 9, 2021

Plane Notes: Carlson Lake Landslide in the Lost River Range, Idaho

My preference even for long trips is to drive. But some trips do require flying. Initially the landscape is familiar and then becomes semi familiar. Looking down at the Lost River Range of Idaho (slight familiarity) I spotted a large landslide.

Carlson Lake Landslide

The slide is about 2 miles long with a headwall at about 8,500 feet elevation and the toe extending out onto the broad alluvial fan at an elevation of 6,700 feet. The slide took place within andesitic and basaltic lava flow formations. 

Schaller (1991) analyzed this slide and obtained a radiocarbon date of 2,420 bp. However, Krueger (2014) utilizing Lake Carlson on the upper part of the slide for past climate analysis got an age date on the upper slide of 9,054 years. It is possible that the slide has had multiple periods of movement that would explain a younger age at the toe of the slide. The slide is located within an active seismic area - the Borah Peak Earthquake ruptured the ground over 21-mile long fault scarp on the opposite side of the Lost Creek Range.    

The trip was a long trip that involved 2 bus rides, 5 planes and 3 trains to get to the destination, but glad to have made it.

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