Ribbon Cliff landslide Washington, and the earthquake of 14 December 1872

Estimates of the epicentral location and maximum intensity of the Dec. 14, 1872, earthquake, the largest and oldest historic earthquake documented in the Pacific Northwest, are controversial largely because the estimates are based on ground effects. The Ribbon Cliff landslide is one of the more critical ground effects used to argue that the epicenter was in the vicinity of Lake Chelan in central Washington. Sketchy historical accounts link the Ribbon Cliff landslide to the 1872 earthquake, but a subsequent study disputed the historical accounts, and, on the basis of dendrochronology, concluded that the landslide probably occurred within a 14-year period that includes the time of the 1872 earthquake. This study supports the historical accounts that link the landslide to the December 1872 earthquake, but it does not prove that seismic shaking triggered the landslide.