Deep Seismogenic Environment in the Southern Section of the Longmenshan Fault Zone on the Eastern Margin of the Tibetan Plateau and Lushan Ms 7.0 Earthquake

摘要: The 2,026 earthquake events registered by the Sichuan regional digital seismic network and mobile array after April 20th, 2013 Lushan 28,188 pieces of data were selected to determine direct P waves arrival times. We applied tomographic method inverse characteristics velocity structure for three–dimensional (3D) wave in mid-upper crust source region earthquake. imaging results combined with apparent magnetization inversion magnetotelluric (MT) sounding retest comprehensively study causes deep seismogenic environment southern section Longmenshan fault zone explore formation Research has shown that there are obvious differences magnetic distribution between northern sections zone. epicenter is located near boundary high low-velocity anomalies favorable a high-velocity section. Moreover, at on dome Ya'an, development solid medium favors accumulation release strain energy. Low-velocity distributed underneath origin, MT 20th also indicate high-conductor anomaly occurs under area origin earthquake, Therefore, we speculated presence high-conductivity body could be related existence fluids. role fluids caused weakening layer inside resulted was prone rupture played triggering