2001年M_(W)7.8昆仑山地震震后形变观测、机制与青藏高原中北部岩石圈流变:认识与挑战  

Postseismic deformation observation,mechanism and lithospheric rheology of the central and northern Tibetan Plateau after the 2001 M_(W)7.8 Kunlun earthquake:Insights and challenges

作　　者：赵德政 屈春燕[1,2] 单新建 张国宏[1,2] 李彦川[1,2] 龚文瑜 宋小刚[1,2] Zhao Dezheng;Qu Chunyan;Shan Xinjian;Zhang Guohong;Li Yanchuan;Gong Wenyu;Song Xiaogang(Institute of Geology,China Earthquake Administration,Beijing 100029,China;State Key Laboratory of Earthquake Dynamics,China Earthquake Administration,Beijing 100029,China)

机构地区：[1]中国地震局地质研究所,中国北京100029 [2]中国地震局地震动力学国家重点实验室,中国北京100029

出　　处：《地震学报》2021年第6期804-816,I0002,共14页Acta Seismologica Sinica

基　　金：中国地震局地质研究所基本科研业务费专项(IGCEA2104,IGCEA1809);自然科学基金(41872229)联合资助。

摘　　要：2001年M_(W)7.8昆仑山地震是近半个世纪以来青藏高原发生的最大震级地震。同震破裂产生的巨大应力扰动驱动控制着显著震后形变。二十年尺度的大地测量数据记录了地震后长时间、大范围、时空依赖的震后形变演化过程及差异,揭示了昆仑山地震破裂段复杂的断层分段震后运动学特征、分段摩擦性质差异和青藏高原中北部岩石圈流变性质/结构横向各向异性。本文简要回顾昆仑山地震后基于二十年尺度时序InSAR和GPS的震后形变观测方法和时空特征,特别是时空密集的InSAR观测,是该构造区震后GPS观测的重要补充及其不可替代的观测手段;总结大范围震后形变模拟方法及其揭示的震后运动过程、多种动力学机制及其关系。最后总结提出昆仑山地震震后形变20年研究取得的科学认识及尚待深入研究的科学问题,一方面要持续性地对东昆仑断裂带大范围地表形变进行观测研究;另一方面,要不断更新震后形变模型,进一步深化对该断裂带地震周期形变、区域构造对周期形变控制作用、复杂断层运动时空演化机制的认识。The 2001 M_(W)7.8 Kokoxili earthquake was the largest earthquake in the central and northern part of the Tibetan Plateau in the recent half century.The large coseismic stress disturbance caused by the coseismic rupture drives and controls the significant postseismic deformation following this major earthquake.A decade of geodetic measurements documented largespatial-scale,long-time-span and time-dependent postseismic deformation and their different evolution processes,and the geodetic measurements also revealed the complex fault kinematics characteristics,friction properties along fault strike and lateral heterogeneity of lithospheric rheological properties/structure in north-central Tibetan Plateau.In this paper,we briefly summarize postseismic deformation observations and their spatiotemporal characteristics of the Kokoxili earthquake based on InSAR time-series and GPS observations on a decadal scale.Particularly,the spatiotemporally dense InSAR observations are deemed as an important supplement to the postseismic GPS observations in this tectonic area.We summarize the models of large-scale postseismic deformation and the revealed postseismic deformation processes,various dynamic mechanisms and their relationships.Finally,we summarize the scientific understanding and unsolved scientific problems associated with the 2001 Kokoxili earthquake in the past 20 years:On the one hand,it is necessary to continuously observe and study the large-scale surface deformation of the Kunlun fault;On the other hand,the postseismic deformation model should be updated continuously to deepen our understanding of the earthquake cycle deformation of the Kunlun fault,the control of regional tectonics on earthquake cycle deformation,and the spatiotemporal evolution mechanism of complex fault movement in this region.

关 键 词：昆仑山地震 震后形变 余滑 黏弹性松弛 岩石圈流变 

分 类 号：P315.725[天文地球—地震学]