青藏高原陆陆碰撞-挤出活动构造体系控震作用:以1990年以来强震活动为例  

The earthquake-controlling process of continental collision-extrusion active tectonic system around the Qinghai-Tibet Plateau:A case study of strong earthquakes since 1990

作　　者：吴中海[1,2,3] WU Zhonghai(Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China;Key Laboratory of Active Tectonics and Geological Safety,Ministry of Natural Resources,Beijing 100081,China;Research Center of Neotectonism and Crustal Stability,China Geological Survey,Beijing 100081,China)

机构地区：[1]中国地质科学院地质力学研究所,北京100081 [2]自然资源部活动构造与地质安全重点实验室,北京100081 [3]中国地质调查局新构造与地壳稳定性研究中心,北京1000811

出　　处：《地质力学学报》2024年第2期189-205,共17页Journal of Geomechanics

基　　金：中国地质调查局地质调查项目(DD20242319,DD20230014);国家自然科学基金云南联合基金项目(U2002211);西藏自治区第1次全国自然灾害综合风险普查项目(2022年地震灾害部分)(XZLX-BMC-2022-053)。

摘　　要：青藏高原是地中海-喜马拉雅地震带上强震活动最频繁的区域之一,深入认识该区的活动构造体系控震效应对于区域强震危险性分析具有重要科学意义。从陆陆碰撞-挤出活动构造体系角度,对青藏高原自1990年以来的MW≥6.0强震活动及控震构造机制进行分析发现,青藏高原陆陆碰撞-挤出构造体系对区域强震活动起到显著控制作用,区域强震事件尤其是MW≥6.5地震主要出现在构造体系的主要边界断裂带上,并显示出相对有规律的时空迁移过程,而且青藏高原东部的多层次挤出-旋转活动构造体系构成了1990年以来强震过程的主要控震构造,其次是喜马拉雅主前缘逆冲断裂带。因此,青藏高原挤出构造体系应是未来强震活动趋势分析最值得关注的区域,尤其是当前最为活跃的巴颜喀拉次级挤出构造单元。对比分析土耳其安纳托利亚板块及周边的强震活动发现,该区具有类似的陆陆碰撞-挤出构造体系及控震效应,表明该构造体系是陆内造山中的一种典型的控震构造。进一步综合分析认为,活动构造体系控震效应的主要表现:一是构造体系中主要断块的边界断裂带通常是强震活动的主要场所;二是构造体系中不同构造带的强震活动常具有联动效应或相互触发关系,其中的复杂或特殊构造部位则是易出现双震或震群活动的场所;三是当构造体系中某个构造单元或构造带处于活跃阶段时,便会出现强震丛集现象。另外,充分认识构造体系中主要活动断层间的协调变形关系,活动断层带上的强震活动的分段破裂行为,以及活动断层上强震原地复发通常存在“周期长、准周期性和丛集性”的特点等,有助于在根据活动构造体系分析区域未来强震活动趋势时更为准确地判定活动断层带的未来强震危险性。[Objective]The Qinghai-Tibet Plateau is one of the most seismically active regions along the Mediterranean-Himalayan seismic belt.Understanding the earthquake-controlling effect of the active tectonic system in this region is crucial for analyzing regional strong earthquake hazards.[Methods]We analyzed earthquake activity with MW≥6.0 since 1990 and their tectonic mechanism around the Tibetan Plateau,focusing on the continental collision-extrusion tectonic system.[Results]The results show that the system plays a significant role in governing regional strong earthquake activity.Specifically,MW≥6.5 earthquakes primarily occur along the main boundary fault zone of this tectonic system,exhibiting a relatively regular spatio-temporal migration process.Moreover,the multi-layered extrusion-rotation active tectonic system in the eastern Tibetan Plateau constitutes the primary earthquake-controlling structure of the strong earthquake process since 1990,followed by the thrust faults of the Himalayan foreland.Therefore,the extrusion tectonic system of the Qinghai-Tibet Plateau should be the focus for the trend analysis of the strong earthquake activity in the future,especially the most active secondary extrusion tectonic units such as the Bayan Har block.Comparative analysis of strong earthquake activities in and around the Anatolian plate reveals similar continental collision-extrusion tectonic systems and earthquake-controlling effects in this area,indicating that this tectonic system is a typical earthquake-controlling structure in the intracontinental orogenic belt.[Conclusion]Further comprehensive analysis suggests that the active tectonic system can significantly control regional strong earthquake activity.Firstly,most of the strong earthquake events occur in the main boundary fault zone of the fault block in the tectonic system.Secondly,the strong earthquake events along different structural zones in the tectonic system often have linkage effects or mutual triggering relationships,and the complex or particular str

关 键 词：青藏高原 陆陆碰撞造山 活动构造体系 强震活动 活动断裂 

分 类 号：P315[天文地球—地震学] P553[天文地球—固体地球物理学]