大凉山断裂带中段普雄断裂晚第四纪古地震

发布时间：2018-06-18 05:24

本文选题：大凉山断裂带 + 普雄断裂　；参考：《地震地质》2016年04期

【摘要】：大凉山断裂带是中国大陆大型强震断裂带鲜水河-小江断裂系的重要组成部分,其中段的普雄断裂是断裂带中最长的1条次级断裂。该次级断裂的古地震活动情况对评价该区域地震活动水平和建立地震灾害预防措施具有重要意义。近年开展的活动断层填图和古地震探槽研究表明普雄断裂是1条晚更新世以来活动强烈的略向W倾的高角度左旋走滑断层。沿断裂开挖的2个探槽分别揭露了2次和3次古地震事件,分别发生在8206 BC—1172 AD、1084—1549 AD和17434—7557BC、1577—959 BC、927—1360 AD。结合探槽古地震结果和历史地震记载,进行建模分析得到断裂的离逝时间约为0.7ka,与距今倒数第2次事件的时间间隔约为2.3ka。同时,根据震级与地表破裂长度的经验公式估算古地震事件震级在7级以上。
[Abstract]:The Daliangshan fault zone is an important part of the Xianshuihe-Xiaojiang fault system in the large strong earthquake fault zone of the Chinese mainland, in which the Puxiong fault is the longest secondary fault in the fault zone. The paleoseismicity of the secondary fault is of great significance to evaluate the seismicity level in the region and to establish earthquake disaster prevention measures. Recent studies on active fault mapping and paleoseismic exploration indicate that the Puxiong fault is a high-angle left-lateral strike-slip fault with a slight W-dip activity since the late Pleistocene. Two trenches excavated along the fault exposed two and three paleoearthquakes, respectively, which occurred in 8206 BC-1172 AD 1084-1549AD and 17434-7557BCU 1577-959BCn 927-1360AD. Combined with the paleoseismic results and historical seismological records, it is found that the time of the fault passing away is about 0.7 kaa, and the time interval between the fault and the penultimate event is about 2.3 ka. At the same time, according to the empirical formula of magnitude and surface rupture length, the paleoearthquake event magnitude is estimated to be more than 7.
【作者单位】：中国地震局地质研究所活动构造与火山重点实验室;
【基金】：财政部重大专项(202208001) 中国地震局地震行业科研专项(201408023)共同资助
【分类号】：P315.2

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