基于高分卫星遥感影像的地震应急滑坡编目与分布特征探讨——以2017年8月8日九寨沟7.0级地震为例

地震应急是减轻地震灾害的重要途径之一。地震应急工作具有时间紧迫、事关重大的特点。2017年8月8日四川九寨沟M_S7.0级地震发生后,为快速、准确地提供地震引发的滑坡灾害分布,本研究基于震后第一天获取到的高分辨率遥感影像（高分二号卫星影像、北京二号卫星影像）,通过人工目视解译的方法初步建立了四川九寨沟地震滑坡编目。结果表明,该地震至少触发了622处同震滑坡,分布在沿使用影像边界框定的面积为3919km2的区域内。本研究还利用这个地震滑坡编目,统计了九寨沟地震滑坡数量和滑坡点密度（LND）与地形（坡度、坡向）、地震（地震烈度、震中距）等因素的关系。结果表明九寨沟地震滑坡多发生在坡度为20°—50°的区域内,滑坡的易发性随着坡度的增加而增加。受地震波传播方向的影响,E、SE向是地震滑坡较易发生的坡向。滑坡的易发程度和地震烈度呈正相关,即随着烈度的增大,滑坡易发性增大。滑坡易发性还随着震中距增加而降低,这是由于地震波能量随震中距的增加而衰减导致的。

Compilation and Spatial Analysis of Co-seismic Landslide Inventory by Using High-resolution Remote Sensing Images in Earthquake Emergency Response-An Example of the Jiuzhaigou MS7.0 Earthquake on August 8, 2017

Earthquake emergency response is one of the significant ways to mitigate earthquake disasters. After a M_S7.0 earthquake occurred in Jiuzhaigou, Sichuan Province on August 8, 2017, we used high-resolution remote sensing images (Gaofen-2 satellite image, Beijing-2 satellite image) obtained at the second day after earthquake, primarily established the inventory of landslide triggered by the Jiuzhaigou M_S7.0 earthquake through artificial visual interpretation in order to obtain distribution caused by earthquake rapidly and accurately. The results show that the earthquake triggered at least 622 co-seismic landslides along the boundary of the image covered by 3,919km². We also statistically analyzed the relations of the number of landslides with topography factors (gradient, aspect) and seismic factors (seismic intensity, distance from epicenter). It is found that landslides mostly occurred at the slope of 20°-50°, and the susceptibility of occurrence increases with the increase of slope gradient. The aspects of E and SE are prone to landslide occurrence because the direction of gradient may be related to seismic wave propagation. It is well correlated between the susceptibility of occurrence and seismic intensity, which suggests that as the intensity increases, the landslide increases. The susceptibility of landslide decreases with the increase of distance from the epicenter. The results provide valuable information for earthquake relief, and are useful in reconstruction and prevention of earthquake-induced geological disasters.