甘肃酒西盆地发现地震地表破裂带  

DISCOVERY OF SURFACE RUPTURE ZONE IN JIUXI BASIN,GANSU PROVINCE

作　　者：刘兴旺[1,2] 袁道阳[1,2] 雷中生[1] 邵延秀[1,2] 

机构地区：[1]中国地震局兰州地震研究所,兰州730000 [2]兰州地球物理国家野外科学观测研究站,兰州730000

出　　处：《地震地质》2016年第3期605-616,共12页Seismology and Geology

基　　金：国家自然科学基金(41402186);中国地震局地震行业科研专项(201408023)共同资助

摘　　要：根据航、卫片解译和野外实地考察,在位于祁连山—河西走廊西段的酒西盆地白杨河背斜北发现1条较新的地震破裂带遗迹,破裂带长度约5km,呈弧形展布,保存较为完整,在最新的洪积扇面上陡坎高度约0.5～0.7m,在冲沟T1阶地上陡坎高度约1.5m,分析认为其为较新的1次地震活动所致。沿断层陡坎探槽开挖表明,此次破裂带形成于约1500aBP,此前断裂还有过活动。根据该地区历史地震资料考证和研究程度,认为该地震地表破裂带可能与365年玉门地震、1785年玉门惠回堡地震或1次漏记的历史强地震有关。Qilian Shan-Hexi Corridor is located at the northeastern margin of Tibetan plateau. Series of late Quaternary active faults are developed in this region. A number of strong earthquakes even large earthquakes occurred in history and present-day. In the past,the study of active faults in the area was mostly concentrated in the northern margin fault zone of the Qilian Shan on the south side of the corridor,while the research on the interior and the north side of the corridor basin was relatively rare.We found a new fault scarp in the northern part of the Baiyanghe anticline in Jiuxi Basin in 2010. It is an earthquake surface rupture zone which has never been reported before. In this paper,we carried out palaeoearthquake trench analysis on the newly found earthquake surface rupture zone and textual research of relevant historical earthquakes data.According to the interpretation of aerial photo and satellite image and field investigation,we found the surface rupture has the length of about 5km. The rupture shows as an arc-shaped line and is preserved intact comparably. The lower terrace and the latest flood alluvial fan are offset in addition to modern gullies. By differential GPS measurement,the height of the scarp is about 0. 5 ～ 0. 7m in the latest alluvial fan and about 1. 5m in the T1 terrace. From the residual ruins along the earthquake rupture zone,we believe the surface rupture might be produced by an earthquake event occurring not long ago. In addition,the rupture zone locates in the area where the climate is dry and rainless and there are no human activities induced damages. These all provide an objective condition for the preservation of the rupture zone. The trench along the fault reveals that the surface rupture was formed about 1500 years ago,and another earthquake event might have happened before it. Based on the textural research on the historical earthquake data and the research degree in the area at present,we believe that the surface rupture is related to the Yumen earthquake in 365, Yumen Huihuip

关 键 词：地震破裂带 酒西盆地 历史地震 甘肃 

分 类 号：P315.2[天文地球—地震学]