New Constraints on Slip Deficit on the Aleutian Megathrust and Inflation at Mt. Veniaminof, Alaska From Repeat GPS Measurements

Abstract

AbstractWe employ an enhanced data set of Global Positioning System (GPS) velocities to reassess the slip deficit along the plate interface of the Alaska‐Aleutian subduction zone. An examination of velocities of sites near Mt Veniaminof, located in the southwest Alaska Peninsula, shows that existing models for tectonic deformation do not accurately predict the local velocity field along this section of the peninsula. In a combined model, we solve for the volcanic inflation signal on the edifice of Mt. Veniaminof and reassess the variations in trench coupling outboard of the volcano. The interseismic deformation near Veniaminof and the eastern Shumagin islands requires an additional model segment with higher slip deficit than the western Shumagin islands. This segment appears to have been the main rupture patch of the 2020 M 7.9 Simeonof earthquake. The volcano inflated over the time period of 2005–2017, although at a lower rate than in 2002–2005.