青藏高原东部鲜水河断裂带地震滑坡危险性评价

Seismic landslide hazards assessment along the Xianshuihe fault zone,Tibetan Plateau,China

鲜水河断裂带是青藏高原东南缘一条大型左旋走滑断裂带,断裂带沿线地形地貌和地质条件复杂,历史地震频发,并诱发大量地震滑坡灾害,对重大工程建设和人民生命财产造成巨大的影响.基于鲜水河断裂带区域地震滑坡防控需要,在研究分析区域地质灾害成灾背景和发育分布特征的基础上,选取鲜水河断裂带两侧约20 km的区域,采用Newmark模型完成了鲜水河断裂带地震滑坡危险性预测评价.结果显示,地震滑坡极高危险性区、高危险区、中等危险区及低危险区分别占研究区总面积的6.28%、11.77%、33.33%和48.62%,危险性较高的地区主要分布在康定-磨西段及大渡河附近,有63.66%的地震滑坡分布在地震滑坡极高和高危险区.成功率(ROC)曲线检验结果表明,此次滑坡危险性性评价的准确率为74.3%,评价结果精确度较高.区内正在规划建设的部分铁路、公路等途经泸定县、康定市等地震滑坡危险性较高的地区,建议在重大工程规划建设时加强隧道口等工程点地震滑坡防控.研究结果将为该区地质灾害防治工作提供参考.

The Xianshuihe fault zone is a large active left-lateral strike-slip fault zone in the southeast margin of Qinghai-Tibet Plateau Southwest China the geomorphology and geological structure along the fault zone is complex and historical earthquakes occur frequently which induce a large number of seismic landslide disasters causing a huge impact on major construction projects and people's lives and properties.For the long-term prevention of seismic landslides in the Xianshuihe fault zone an area of about 20 km on both sides of the Xianshuihe fault zone was selected for remote sensing interpretation and field geological survey a total of 399 historical seismic landslides were found in the region with overall characteristics of high remote one slide to the bottom and cracked but not slipped.On the basis of studying and analyzing the disaster background and development and distribution characteristics of regional geological disasters the Newmark model was used to complete the seismic landslide hazards assessment with exceeding probability 10%of 50 years in Xianshuihe fault zone.The results showed that the extremely high-risk area high-risk area medium-risk area and low-risk area of seismic landslides account for 6.28%11.77%33.33%and 48.62%of the total area of the study area respectively.The Kangding-Moxi section and the vicinity of Dadu River are areas with high seismic landslide hazards.63.66%of seismic landslides are distributed in extremely high and high seismic landslide hazards areas the test results of the success rate ROC curve show that the accuracy of the landslide risk assessment is 74.3%and the accuracy of the evaluation results is high.Some railways and highways that are being planned and constructed along the Xianshuihe fault zone pass through areas with high seismic landslide risk such as Luding County and Kangding City.It is suggested to strengthen the prevention and control of seismic landslides at the key engineering points during the major projects planning and construction period such as the tunnel entrances.The study results of this paper will provide a reference for the geo-hazards prevention and control in this area.