Irregular western margin of the Yangtze block as a cause of variation in tectonic activity along the Longmen Shan fault zone, eastern Tibet

摘要: On 12 May 2008 and 20 April 2013, respectively, the devastating magnitude 7.9 (Wenchuan) 7.0 (Ya’an) earthquakes struck southwestern Longmen Shan fault zone (LMSFZ), eastern margin of Tibetan Plateau. These events were notable because they occurred in a heavily populated area resulted severe damage loss life. Here we present an integrated analysis potential field anomalies crustal-scale seismic reflection image to investigate crustal structure some tectonic relationships associated with these events. Our results show that western Yangtze block possesses irregular extends westward beyond LMSFZ northeast merges gradually southwest. We interpret this variation deep create lateral heterogeneity local stress regime explains observed variations geometry slip distribution, as well seismicity, LMSFZ. This structu...