The July 2019 Ridgecrest, California, Earthquake Sequence: Kinematics of Slip and Stressing in Cross-Fault Ruptures

摘要

The July 2019 Ridgecrest, California, earthquake sequence produced cross-fault ruptures from a M(w)6.4 left-lateral foreshock and a M(w)7.1 right-lateral mainshock. We use interferometric synthetic aperture radar and satellite optical imagery to characterize the surface displacements and subsurface fault slip characteristics of the sequence. We document similar to 46 km of surface rupture and peak slip values of similar to 5 m associated with the M(w)7.1 and evidence that the two ruptures crossed each other. We additionally document evidence of triggered creep along 20-25 km of the central Garlock fault. Static stress change analysis shows that the foreshock sequence systematically promoted slip at the M(w)7.1 hypocenter. Moreover, we find static stress changes promoted slip on the Garlock fault only in locations where we document surface creep, strongly indicating that the Garlock fault is sensitive to static stress changes. A potential rupture of the Garlock fault where slip was promoted could produce a M(w)6.7-7.0 earthquake.