高分辨率多光谱的芦山地震次生地质灾害遥感监测与评估

High Resolution Remote Sensing Monitoring and Assessment of Secondary Geological Disasters Triggered by the Lushan Earthquake

2013年4月20日芦山7.0级大地震发生后,产生大面积滑坡、崩塌、碎屑流等次生地质灾害,造成大量人员财产损失,并严重阻碍了应急救援和灾后重建工作的顺利开展。利用快速获取的震前和震后航空、航天等多源遥感数据、地形地貌和地质构造数据,首先结合次生地质灾害在高分辨率多光谱影像上的形态、结构和纹理特征,对地震重灾区次生地质灾害的数量和空间分布进行了有效监测。结果显示：芦山县、宝兴县和天全县次生地质灾害最为严重,各有164处、126处和71处大型次生地质灾害点。并结合GIS技术对这些次生地质灾害的空间分布规律,特别是同区域地质构造、烈度和地形地貌之间的关系进行了综合分析和评估。评估结果显示：在监测区存在四个次生地质灾害高发区,其中一个聚集在震中6公里范围内,其他三个沿本区域两个主要地质断层分布;超过97%的次生地质灾害位于烈度Ⅶ~Ⅳ度、坡度25°~50°且海拔800~2 000m之间的区域。最后结合震害遥感监测评估结果,对震后恢复重建规划及实施提出建议。

The secondary geological disasters triggered by the Lushan earthquake on April 20,2013,such as landslides,collapses,debris flows,etc.,had caused great casualties and losses.We monitored the number and spatial distribution of the secondary geological disasters in the earthquake-hit area from airborne remote sensing images,which covered areas about 3 100km2.The results showed that Lushan County,Baoxing County and Tianquan County were most severely affected;there were 164,126 and 71secondary geological disasters in these regions.Moreover,we analyzed the relationship between the distribution of the secondary geological disasters,geological structure and intensity.The results indicate that there were 4high-hazard zones in the monitored area,one focused within six kilometers from the epicenter,and others are distributed along the two main fault zones of the Longmen Mountain.More than 97%secondary geological disasters occurred in zones with a seismic intensity of VII to IX degrees,a slope between 25 Adegrees and 50 Adegrees,and an altitude of between 800 and 2 000 m.At last,preliminary suggestions were proposed for the rehabilitation and reconstruction planning of Lushan earthquake.According to the analysis result,airborne and space borne remote sensing can be used accurately and effectively in almost real-time to monitor and assess secondary geological disasters,providing a scientific basis and decision making support for government emergency command and post-disaster reconstruction.