资源环境科技发展态势分析平台

The 17 July 2017 Komandorsky Islands M-W 7.8 earthquake involved arc-parallel right-lateral patchy strike-slip faulting along similar to 400km of the Bering Fracture Zone (BFZ) in the westernmost Aleutian Islands back arc. The large size of the earthquake indicates that the BFZ serves regionally as the primary plate boundary extending from the Near Islands to Kamchatka, with the fore-arc Komandorsky Sliver translating rapidly parallel to the Aleutian Trench. The slip distribution is determined by analysis of seismic, tsunami, and geodetic observations. Fault displacements of 4 to 8.5m, mostly in the upper 15km, but with localized extension to 20 to 30km depth along a similar to 100km long segment of the BFZ, are comparable to the possible slip deficit since the last major earthquakes in this region in 1849 and 1858, given an estimated 5.1cm/yr rate between the Komandorsky Sliver and the Bering Plate.

Plain Language Summary A large earthquake struck the westernmost portion of the Aleutian Island arc on 17 July 2017. In this region the Pacific plate is moving relative to the North American plate parallel to the plate boundary, with no convergence. As a result the plate motion is accommodated on a strike-slip fault in the upper plate, located along the Bering Fracture Zone. The earthquake produced slip and aftershocks along a 400 km long stretch of the Bering Fracture Zone in a magnitude 7.8 earthquake. The slip distribution and time history are determined by modeling seismic, geodetic, and tsunami data. The event is comparable in length and seismic moment to the 1906 San Francisco earthquake on the San Andreas Fault.