逻辑回归模型在玉树地震滑坡危险性评价中的应用与检验

    LOGISTIC REGRESSION MODEL AND ITS VALIDATION FOR HAZARD MAPPING OF LANDSLIDES TRIGGERED BY YUSHU EARTHQUAKE

    • 摘要: 2010年4月14日07时49分(北京时间),青海省玉树县发生了Ms7.1级大地震。作者基于高分辨率遥感影像解译与现场调查验证的方法,圈定了2036处本次地震诱发滑坡。这些滑坡受地震地表破裂控制强烈,规模相对较小,常常密集成片分布。滑坡类型多样,以崩塌型滑坡为主,还包括滑动型、流滑型、碎屑流型、复合型等类型的滑坡。本文基于地理信息系统(GIS)与遥感(RS)技术,应用逻辑回归模型开展玉树地震滑坡危险性评价,并对结果合理性进行检验。应用GIS技术建立玉树地震滑坡灾害及相关滑坡影响因子空间数据库,选择高程、斜坡坡度、斜坡坡向、斜坡曲率、与水系距离、坡位、断裂、地层岩性、归一化植被指数(NDVI)、公路、同震地表破裂、地震动峰值加速度(PGA)共12个因子作为玉树地震滑坡影响因子,在GIS平台下将这些因子专题图层栅格化。应用逻辑回归模型得到每个因子分级的回归系数,然后建立滑坡危险性指数分布图。利用玉树地震滑坡空间分布图对滑坡危险性指数图进行检验,正确率达到83.21%。滑坡危险性分级结果表明,在占研究区总面积4.97%的"很高危险度"的较小范围内,实际发育滑坡数量为766个,占总滑坡面积的比例高达37.62%,表明地震滑坡危险性评价结果良好。不同危险性级别的滑坡点密度统计结果表明,滑坡点密度随着危险性级别的升高而非常迅速的升高。

       

      Abstract: At 07: 49(Beijing time)on April 14, 2010,a catastrophic earthquake with Ms 7.1 struck Yushu County,Qinghai Province,China.2036 landslides were interpreted from aerial photographs and remote sensing images,verified by selected field checking.The spatial distribution of the landslides was evidently strongly controlled by the locations of the main surface fault ruptures.The landslides commonly occurred close together.Most of the landslides were small.The landslides were of various types.They were mainly shallow,disrupted landslides,but also included rock falls,deep-seated landslides,liquefied landslides, and compound landslides.The aim of this study was to apply and validate logistic regression model for the Yushu earthquake triggered landslide hazard mapping.The Geographic Information Systems(GIS) and Remote Sensing(RS)technologies were used.A spatial database was developed and analyzed using GIS technology.It includes the landslides and associated controlling parameters which may have influence on the occurrence of landslides..The twelve factors that influence landslide occurrence were created in raster data format base on GIS platform.They include elevation,slope angle,slope aspect,slope curvature,slope position,drainages,lithology,faults,roads,normalized difference vegetation index(NDVI),co-seismic main surface fault-ruptures, and peak ground acceleration(PGA).the coefficients of the evaluation variables were estimated using logistic regression model and were used to calculate the landslide hazard index for the entire study area within a GIS environment.The validation result showed a success rate of 83.21% between the hazard map and the locations of Yushu earthquake triggered landslides.The landslide hazard assessment rank result showed that the"very high hazard"level covers about 4.97% of the total study area but has a number of 766 landslides(37.62% of the total landslides number),which representing good quality of the landslide hazard map.The sequence of the landslide number density percentage descends expeditiously accompany with the hazard level decreasing.

       

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