【摘要】 基于2009年1月1日至2013年5月6日四川地震台网、重庆地震台网记录的龙门山断裂带南段587个地震的5 012个P波到时数据,利用最小一维速度模型方法反演了龙门山断裂带南段地壳一维P波速度模型及台站校正值,并将其应用到龙门山地区地震重定位中。结果表明,台站校正值表征出龙门山断裂带南段地表速度结构的横向不均匀性,青藏高原的彭灌杂岩体及宝兴杂岩体在近地表表现为高速异常,而四川盆地的第四纪沉积表现为低速异常。重定位后地震震源在北西向的剖面上呈明显的条带状并向北西倾斜,该地震带与宝兴杂岩下方的滑脱带延伸趋势一致。此外,该地震带上方分布着一条反冲地震带,两地震带呈"y"型分布,这可能是宝兴杂岩上方的岩层为调节逆冲过程受阻而产生的反冲运动所致。更多还原

【Abstract】 Using 5 012 P wave arrival times of 587 earthquakes occurred at the south segment of Longmenshan Fault recorded by Sichuan and Chongqing Seismic Netw ork from Jan. 1,2009 to M ay. 6,2013,we obtained the P wave velocity model and station correction value by the minimum 1D velocity model method,which are applied in earthquake relocation in Longmenshan area. The result shows that the station correction value represents the lateral heterogeneity of surface velocity structure in the south segment of Longmenshan Fault. There appeared the high velocity anomaly in the near surface of Pengguan and Baoxing complex rock bodies in Tibet plateau,whereas obvious low velocity anomaly in Quaternary deposit of Sichuan basin. The distribution of epicenter after relocation shows an obvious banding and dips to NW in NW profile,which is corresponding to the extending trend of slip band below Baoxing complex rock body. Above the NW dipping seismic belt,there is a recoil seismic belt,and these tw o seismic belts distribute in "y "type,which may due to the recoil movement generate from that the rock stratum above Baoxing complex rock body blocked in the process of adjusting the thrusting.更多还原