Further analysis of the geodetic strain measurements on the Denali Fault in Alaska

Abstract

Unbiased analysis of repeated surveys of a section of the primary triangulation arc along the Richardson Highway provides no evidence for lateral deformation on the Denali fault, a major dextral transcurrent fault in the Alaska range. The measured shear strain accumulated in the 29-year period between surveys is consistent with an extension normal to the fault of about 23 ± 4 μstrain and apparently represents strain release at the time of the 1964 Alaska earthquake. A dislocation model for the Alaska earthquake is used to demonstrate that strain relaxation of this magnitude at the Denali fault is consistent with other geodetic strain observations. The absence of significant right lateral deformation on the Denali fault in the 29-year period between surveys suggests that the rate of strain accumulation there must be quite small (engineering shear strain rate is probably 0.1 μstrain/yr or less).