芦山Ms7.0地震前龙门山断裂带西南段区域形变特征分析及发震模型探讨

Regional Deformation Characteristics in the Southwestern Segment of Longmen Mountain Fault Zone before Lushan Ms7.0 Earthquake and Possibly Induced Earthquake Model

利用2010年和2013年两期精密水准测量数据分析了芦山Ms7.0地震前龙门山断裂带西南段的区域形变特征。结果显示,芦山地震前龙门山断裂带西南段的天全-泸定区域垂直形变速率为6~8mm/a,远大于汶川地震前的形变速率,汶川地震对芦山地震前该区域库伦应力值的积累起加速作用;临近四川盆地的雅安至名山区域的垂直形变速率为-3^-6mm/a。从芦山地震和汶川地震的地震破裂带及余震分布区域来看,两次地震中间出现一段"地震空区",应力可能会在空区加速积累,应加强该区域地震监测和预报。

The regional deformation characteristics of the southwestern segment of Longmen Mountain Fault Zone before the Lushan Ms7. 0 earthquake were analyzed by using the precise re-leveling data in 2010 and 2013. The results indicate that the vertical deformation rate of the Tianquan-Luding area in the southwestern part of the Longmen Mountain Fault Zone was 6-8 mm /a,which was far higher than that of this region before the Wenchuan Ms8. 0 earthquake. The Wenchuan Ms8. 0 earthquake accelerated accumulation of the Coulomb stress value in the research area before occurrence of Lushan Ms7. 0 earthquake. The vertical deformation rate of the Ya＇an-Mingshan area close to the Sichuan Basin was --3 --6 mm/a. In terms of the rupture zone and aftershock distribution induced by the Lushan earthquake and Wenchuan earthquake, a ＂seismic gap＂ between two earthquakes might accelerate stress accumulation. Therefore, monitoring the ＂seismic gap＂ and earthquake prediction should be strengthened.