Variations in rupture speed, slip amplitude and slip direction during the 2008 Mw 7.9 Wenchuan Earthquake

摘要: SUMMARY Theoretical and observational evidence implies that variable rupture velocity may be associated with high fault slip moment release rates during earthquakes. We investigate this relationship for the 2008 Mw 7.9 Wenchuan China, Earthquake, which appears to have experienced a highly rate. used an empirical Green's function (EGF) deconvolution analysis of teleseismic waveforms retrieve primary characters event. Based on field observations deconvolved source–time from thrust strike-slip EGFs, we divided ruptured into three segments, allowing us determine spatial distribution different average velocities each segment. deployed grid search analysis, in integrated waveform inversion forward modelling regional surface wave optimum speed Our result shows Earthquake had amplitude, direction were spatially variable. The earthquake initially nearly pure motion slow 1.7 km s–1. Then, increased up 3.1–3.3 s–1 produced largest second segment, where two parallel faults simultaneously. Rupture then slowed down 2.5–2.9 final underwent primarily motion. In total, extended 300 range 2.6–2.9 (close shear velocity) segment related simultaneous well-established pre-existing structures. are likely strongly rotational 3-D deformation eastern Tibetan Plateau margin, leads heterogeneous stress Longmen Shan region.