2013年四川芦山地震次生山地灾害发育规律

    Features of secondary mountain hazards triggered by the 2013 Lushan Earthquake, Sichuan Province

    • 摘要: 2013年4月20日8时02分,青藏高原东缘龙门山南部地区发生了芦山地震(Ms 7.0),此次地震诱发了大量次生山地灾害。以地震重灾区宝兴作为研究区,利用卫星遥感影像、数字高程模型和高清航拍图像,以及崩塌滑坡数据统计分析,并结合野外调查研究,对区内次生山地灾害的空间分布与岩性、断裂和坡度关系进行了分析和探讨,总结了宝兴地区地震诱发的次生山地灾害发育规律:①以中小型崩塌滑坡为主,且沿省道S210集中分布;②崩塌滑坡主要发生在宝兴杂岩区浅表强风化层及第四系松散堆积层;③研究区内发育的五龙断裂和小关子断裂不是芦山地震的同震断裂;④该区域70%的崩塌滑坡发生在坡度大于30°的区域范围内,30~40°坡度段崩塌滑坡最为集中;⑤人类工程活动是宝兴地区次生山地灾害集中发育在S210省道两侧的主要原因;⑥在汶川地震和芦山地震2次地震及其余震的频繁加载作用下,宝兴地区崩塌滑坡的活动性增加,未来几年将是中小规模崩塌滑坡发育的高峰期。

       

      Abstract: At 8:02 am, 20 April 2013, the Ms 7.0 Lushan earthquake struck the southern area of the Longmen Mountain on the eastern margin of the Tibetan Plateau in Sichuan Province. A lot of geohazards followed this earthquake. Taking the hazards-prone Baoxing area as the study area and based on the remote sensing analysis, digital elevation model, statistic analysis and field investigation, the authors analyzed the distribution of the geohazards and the relationship between hazards and lithology, faults and slope gradient and, on such a basis, summarized the features of seismic geohazards in the Baoxing area: ①Hazards are mostly small or medium-sized collapses and landslides, and are mostly distributed along road S210. ②Collapses and landslides mainly occur in the highly weathered layers of the Baoxing complex and Quaternary superficial layer. ③Wulong and Xiaoguanzi faults are not coseismic faults of Lushan earthquake. ④In the study area, 70% of collapses and landslides occur in the areas whose slope is steeper than 30°, and the slope of most geohazards range from 30° to 40°. ⑤Human engineering activity is the main controlling factor of the geohazards distributed along road S210. ⑥Because the slopes impacted by the Wenchuan and Lushan earthquakes become very unstable, landslides, collapses and debris flow are more prone to occur, and hence the coming several years will be the high-incidence period.

       

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