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2008年5月12日,青藏高原东缘龙门山断裂带发生汶川MW7.9地震,该地震使得北川—映秀断裂、灌县—江油断裂发生了同震破裂。本文主要利用震后通过复测获得的GPS同震形变场,采用Yabuki&Matsu’ura反演计算方法和分段平面断层模型,反演了地震同震滑动分布。结果表明:映秀—北川主破裂带的断层错动,在映秀附近以逆冲滑动为主,而在北川以北,其走滑运动明显大于逆冲,这一结果与震后地质调查结果与通过地震波研究获得的断层破裂特征相一致;反演得到的最大滑动量达到9.3m和9.6m,分别对应于这次地震中地表破坏最为严重的北川和映秀地区;由所获得的滑动分布计算的地震矩为8.07×1020 N.m,对应的震级为MW7.9。研究结果初步显示,Yabuki&Matsu’ura反演方法可适用在内陆地震断层反演计算中。
On May 12, 2008, an Wenchuan MW7.9 earthquake hit the Longmen Shan fault belt on the eastern margin of the Qinghai-Tibet Plateau, causing an earthquake-induced coseismic rupture of the Beichuan-Yingxiu fault and the Guanxian-Jiangyou fault. In this paper, the GPS coseismic deformation field obtained through the re-measurement after the earthquake is mainly used. The Yabuki & Matsu’ura inversion method and the section plane fault model are used to invert the seismic coseismic slip distribution. The results show that the fault of Yingxiu-Beichuan fault ruptures mainly thrusting near Yingxiu, while the strike-slip movement of Yingxiu-Beichuan fault is larger than thrusting north of Beichuan. This result is consistent with the results of post-earthquake geologic survey The fault rupture features obtained by the seismic wave studies are consistent. The maximum slippage obtained by the inversion reaches 9.3m and 9.6m, corresponding to the Beichuan and Yingxiu regions with the most serious surface damage in this earthquake. The earthquakes calculated from the obtained slippage distribution Moment of 8.07 × 1020 Nm, the corresponding magnitude of MW7.9. The preliminary results show that the Yabuki & Matsu’ura inversion method can be applied to inland seismic fault inversion calculation.