Complex conjugate rupture of the 2014 Mw 6.2 Ludian (Yunnan, China) earthquake

Abstract

The Mw 6.2 Ludian earthquake, struck Yunnan, China on August 3rd, 2014, leading to a complex aftershock distribution and enormous disaster. The Ludian earthquake is well recorded by the China Earthquake Network. The rupture process of the Ludian earthquake is constrained by the more local strong motion data including the LLT station with epicentral distance of ∼2 km and teleseismic body waves and surface waves in this study. The local strong motion data constrained the epicenter’s location and rupture process better. Waveform fit of key local strong-motion stations supported that the Ludian earthquake ruptured two conjugate faults with strike angles of 77° and 160°, respectively. The rupture simultaneously took place on two conjugate faults and lasted approximately 10 s. The peak slip, rise time, and average slip rate are 0.63 m, 0.69 s, and 2.12 m/s, respectively. The result shows that the main rupture zone was on the fault with a strike of 160°. The depth of the major slip patch was 0–4 km with a centroid depth of 2 km. It indicates that the shallow slip is the main reason for the enormous disaster from the earthquake source perspective.