【摘要】 2008年10月6日16时30分（北京时间）,西藏自治区拉萨市当雄县发生M_s6.6级地震.震中位于亚东谷露近南北向裂谷带北段,是该活动构造带近年来发生的一次较大地震.我们利用中国地震台网中心（CENC）和美国地震学联合研究所（IRIS）提供的宽频带地震记录资料,基于点源和有限断层模型,通过波形拟合反演了该地震的震源过程.结果表明,本次地震的发震断层面走向为183.3°,倾角为49.5°,滑动角约为-115°,最大滑动量达130 cm,地震震源的深度为9.6 km,地震的标量地震矩为2.85×10¹⁸N·m,破裂持续时间约10 s.根据地震破裂的几何学和运动学特征,推测该地震主要发生在亚东—谷露南北向裂谷活动构造带内的一个高角度西倾断层上,是一个以拉张为主且有一定的右旋分量的破裂事件,这与青藏高原现今GPS测量所揭示的该地区地壳运动特征基本一致,暗示了青藏高原南部从西向东地表运动从北北东向到南东东向的运动学转变所导致的地壳在近东西方向上的拉张变形特征.更多还原

【Abstract】 The rupture process of the Oct.6, 2008 Damxung earthquake （M_s6.6） is studied by using the point source and finite fault model.The observed broadband seismograms used in the inversion were retrieved from DMC （Data Manager Center） of China Earthquake Networks Center （CENC） and of Incorporated Research Institute for Seismology （IRIS）.Historical earthquake records indicated that this event is one of the strongest earthquakes in central Tibet in recent years, and its epicenter is located around the N-S trended Yadong-Golug rift zone in southern Tibet.Our inversion results show that the earthquake occurred on a west-dipping normal fault with the focal depth of 9.6 km, the fault plane has a strike of 183.3°, a dip of 49.5°. The rupture process lasted about 10 seconds with a maximum slip reaching 130 cm, consistent with a moment release of 2.84×10¹⁸ N·m.The dynamic rupture process obtained in this study consists with the crustal movement obtained from GPS observations, implying that this earthquake was triggered by extension stress induced by transition of crustal niovement from the direction of NNE to SSE from central southern Tibet to the eastern Himalaya Syntax.更多还原