Fault-valve behavior in the 2017 Mw 5.4 Pohang, South Korea, Earthquake Sequence

Abstract:

We present the new characteristics of the 2017 Pohang earthquake sequence: aftershock migration occurred on both sides of the two intersecting faults northeast of the mainshock epicenter, matching fluid diffusion process and fault-valve behavior through the two intersecting faults. A dislocation model involving the mainshock coseismic rupture of the fault intersection between the two faults is established for the underground fault system, which accounts for previously reported observations such as locally concentrated uplift and the non-double-couple mechanism of the mainshock. Our results could provide a key step in the examination of both fluid-faulting interactions and rupture dynamics for the Pohang earthquake.