Accurate Location of the Lushan, Sichuan M7.0 Earthquake on 20 April 2013 and Its Aftershocks and Analysis of the Seismogenic Structure

Abstract The M7.0 Lushan earthquake and its aftershocks in 9 days were relocated by the double difference algorithm and a layered velocity model, using the seismic phases recorded at stations within 150 km including the fixed stations of the Sichuan earthquake network center, temporary stations, and reservoir stations. The events analyzed include the main shock and its 3324 aftershocks. The results show that the origin time of the main shock is 8:02:46.8 on 20 April 2013, hypocenter location 30.278°N, 102.989°E and the focal depth 16.67 km. The main rupture is about 40 km long, 20 km wide with an apparent area 800 km2. It strikes in southwest and dips about 40°. Most aftershocks occurred at depths 10∼22 km, concentrating on the hanging wall of the Dayi‐Mingshan fault, forming a southwest‐trending belt on the surface. Based on these and other data, this paper makes a preliminary analysis of the seismogenic structure of the Lushan event.