Near-source modeling of the Loma Prieta earthquake: Evidence for heterogeneous slip and implications for earthquake hazard

摘要: I have analyzed records from 20 strong-motion instruments that recorded the 1989 Loma Prieta earthquake ( ML = 6.9) to determine spatial and temporal distribution of slip using a tomographic back-projection technique. find ruptured bilaterally at approximately 80% local shear-wave velocity over distance slightly more than 30 km 13 northwest southeast hypocenter. Slip within rupture zone was highly variable both in magnitude direction. hypocenter immediately up dip relatively low, about 1 m. There were two main areas concentrated slip, one centered 7 depth 14 other 6 12 km. Peak amplitude on these high-slip patches exceeded 4.5 A surprising aspect model is rake varies being predominately strike-slip reverse northwest. Despite this variation rake, average determined data agreement with teleseismically. correlation between high low aftershock activity. simple explain observation are also strength, which only during infrequent large mainshocks. Other fault weaker may seismically aseismically. Most occurred 9 16 structure dips southwest runs underneath surface trace San Andreas 8 10 This complicates assessment seismic hazard southern Santa Cruz Mountains segment fault.