天全-荥经断裂晚第四纪活动的地貌证据

天全-荥经断裂是青藏高原东南缘的1条晚第四纪且活动资料较少的断裂，在2008年汶川M 8.0地震之后，龙门山断裂带西南端未来的地震危险性受到关注。对天全-荥经断裂晚第四纪活动特征的获取有助于理解该区地震危险性的评价。通过遥感影像解译，结合野外调查和断错地貌测量，分析了天全-荥经断裂在荥经下坝村至桂花村切过荥经河河谷晚第四纪地貌区的活动证据。断裂沿线形成冲积扇断错、阶地坎断错和断坎等地貌，并沿断裂发育滑坡。晚第四纪以来断裂以左旋走滑活动为主，其中T2/T2'阶地坎被左旋断错22—24m。利用荥经河阶地与青衣江河流阶地对比，认为该断裂20—40ka以来左旋走滑速率为0.6—1.1mm/a。仍需要从古地震等方面开展工作，来进一步确定天全-荥经断裂的地震危险性。

Activity of the Tianquan-Yingjing Fault in Late Quaternary-evidence from Geomorpgology

Tianquan-Yingjing fault is well documented about the late quaternary activity as part of the southeastern margin fault system of the Tibet plateau. Most past work has focused on the seismic risk of the southwestern part of the Longmenshan fault after the 2008 Wenchuan earthquake. In this paper we investigated the fault trace distribution and geomorphologic evidence of fault activities from satellite image and field work for the Tianquan-Yingjing fault along the valley of Yingjing river. We found some offsets of terrace riser and alluvial fan in Xiaba, Miaogang and Guihua village. The Tianquan -Yingjing fault slip sinistrally from the offset riser T2/T2'' with an amount of 22-24m in the past 20-40 ka. The slip rate was estimated to 0.6-1.1mm/a. Further study is suggested on paleoearthquakes for the seismic risk assessment for the Tianquan-Yingjing fault.