Stick-slip nucleation triggering of Wenchuan earthquake

Abstract

The MS8.0 Wenchuan earthquake occurred on May 12th, 2008 on the steeply reverse fault of the Longmen Shan fault zone, Western China. Catastrophic failure and rupture occurred along the listric sliding surface. Several numerical simulations have been performed to reconfigure the dynamic processes of this strong earthquake. However, few scientific studies on the stick-slip of the listric fault have been conducted. In this study, finite element method is utilized to simulate the instant stick-slip fault responses at the triggering moment. The fault surface is a non-continuous and frictional contact interface. The simulation results demonstrated that the sliding friction and sticking friction interact spatially. This interaction occurred temporarily on swarms of slip patches, rather than the entire fault slipping surface. Stick-slip causes serrated energy release, and transient aseismic slip can occur spontaneously. These tremors propagate from the epicenter upwards to the ground surface. Therefore, they may provide important details on earthquake onset rupture.

Keywords

• Stick-slip
• Tremor
• Wenchuan earthquake
• Longmen Shan
• Earthquake triggering
• Friction