阿尔金断裂带阿克塞段半果巴探槽揭露的古地震事件  

PALEOSEISMIC EVENTS IN BANGUOBA TRENCH ALONG AKSAY SEGMENT OF THE ALTYN TAGH FAULT ZONE

作　　者：李康[1] 徐锡伟[1] 罗浩[1] Paul Tapponnier Yann Klinger 高明星[1,2] 

机构地区：[1]中国地震局地质研究所,活动构造与火山重点实验室,北京100029 [2]Earth Observatory of Singapore, Singapore [3]Tectonics, Institut de Physique du Globe de Paris, Sorbone Paris Cite, CNRS

出　　处：《地震地质》2016年第3期670-679,共10页Seismology and Geology

基　　金：国家自然科学基金(91214201)资助

摘　　要：阿尔金断裂带是青藏高原北边界的1条近EW向延伸长约1600km的大型左旋走滑断裂带,也是晚第四纪活动性最强的断裂带之一,被分为11个破裂段。利用高精度卫星影像结合野外地质地貌调查,通过Trimble VX扫描测量了阿尔金断裂带阿克塞段半果巴观察点的断错微地貌,显示冲沟左岸T1阶地保存了最新1次地震的位错约6～7m。选择冲沟右岸跨断塞塘开挖探槽,采集了14C样品进行年代测定,对该探槽的古地震事件进行了分析。探槽揭示了12套地层单元,记录了4次古地震事件,结合之前的研究,利用逐次限定方法可以把阿克塞段的最新2次古地震事件的发生时间分别限定在1 180a BP左右和507～230a BP。As the boundary between the northern edge of the Tibetan plateau and the Tarim Basin,the active left-lateral strike-slip Altyn Tagh Fault（ ATF） is a first-order structure accommodating the ongoing continental collision between India and Asia and extends from northwestern Tibet to eastern Gansu Province with a whole length of ～ 1600km. It is regarded as one of the most active fault in Euro-Asia block and has been segmented eleven rupture segments. This study utilizes the highresolution image data（ Google Earth） in combination with detailed field investigation on the Aksay segment of the ATF to scan the gully offset by Trimble VX,which suggests that the latest earthquake offset is 6 ～ 7m. Through trenching and radiocarbon dating of charcoal samples,paleoseismic events of this segment are analyzed. The trench has revealed many different deformed and dislocated strata,which display four paleoseismic events. Combined with the previous research and using the progressive constraining method,we constrained the paleoseismic events in this segment,and the results suggest that the penultimate and the most recent event occurred ～ 1180 a BP and 507 ～230a BP,respectively.

关 键 词：阿尔金断裂带 阿克塞段 古地震 冲沟位错 

分 类 号：P315.2[天文地球—地震学]