论文部分内容阅读
2008年汶川Mw7.9级地震后,于2009～2011年间,穿过汶川地震所在的龙门山断裂带中段和2013年芦山7.0级地震所在的龙门山断裂带西南段,沿两条剖面开展了大地电磁观测,使用相位张量和二维反演等多种先进的分析解释方法,获得了两条剖面的可信度高的二维电性结构.通过对龙门山西南段和芦山地震区深部结构的深入研究发现,它们与龙门山断裂带中段及汶川地震区深部结构既有相同之处,也有明显差别.西南段西侧松潘-甘孜地块上地壳高阻层下约10km深度出现地壳高导层(HCL),比中段的深度小.西南段自地表到上地幔顶部也存在龙门山高阻体(HRB),但是龙门山高阻体规模比中段的小,其内既没有与西侧地壳高导层相通的低阻层,也没有像汶川地震区那样在龙门山高阻体内部震源区附近出现局部的低阻区.芦山地震发生在龙门山高阻体东侧边界附近,在双石-大川断裂附近,但是汶川地震发生在龙门山高阻体内部,这些构成了芦山地震和汶川地震孕震环境的差异.对青藏高原东部地壳高导层与地壳变形的关系,以及龙门山断裂带不同位置潜在的地震危险性进行了分析.
After the Wenchuan Mw7.9 earthquake in 2008, it crossed the middle segment of the Longmenshan fault zone where the Wenchuan earthquake was located and the southwestern segment of the Longmenshan fault zone where the 7.0-magnitude Lushan earthquake in 2013 was carried out between 2009 and 2011 along the two sections Electromagnetic observation, the use of phase tensor and two-dimensional inversion and other advanced analysis and interpretation methods, access to the two sections of the high credibility of the two-dimensional electrical structure.By the Longmen Shannan Luan Seismic Zone and deep structure Depth study found that they both have similarities and differences with the Longmenshan fault zone and the deep structure of the Wenchuan earthquake area.The crustal high conductance occurs about 10 km below the upper crust in the Songpan-Garzê block on the west side of the southwestern section (HCL), which is smaller than the depth of the mid-section.The Longmenshan high-resistivity body (HRB) also exists in the SW section from the surface to the top of the upper mantle, but the scale of the Longmenshan high-resistivity body is smaller than that in the middle section, Low resistivity layer in the same layer and no local low resistivity region near the source region of the Longmenshan high resistivity body like the Wenchuan earthquake.The Lushan earthquake occurred near the eastern boundary of the Longmen Shan high resistivity body and near the Shishi-Ochuan fault, but The Wenchuan earthquake occurred inside the Longmenshan high-resistivity body, which formed the difference of seismogenic environment between the Lushan and Wenchuan earthquakes.The relationship between the crustal crustal deforma- tion and the crustal deforma- tion in the east of the Qinghai-Tibet Plateau and the potential seismic risk in the Longmenshan fault zone Analyzed.