Mulit-source SAR Remote Sensing Data for Rapid Response to Wenchuan Earthquake Damage Assessment
多源雷达遥感数据汶川地震灾情应急监测与评价

SyntheticApertureRadar (SAR) has significantadvantages in disastermonitoring thatare allweather, inde- pendentof illumination mi aging capabilities and strong stereoscopic sense. SAR technology played irreplaceable role in rapid response toWenchuanEarthquakemonitoring and damage assessment. WenchuanEarthquake generated numerousof landslides, landslide lakes and dams, aswellasdebris flows. Theirquantity, scale and dmi ension brake historic records. Landslides buried towns and villages, blocked up river channelswhich inundated villages and heavily destroyed the road networks andmade the rescuework extremely difficult. The hardship ofrescue effortswasbeyond ofhuman mi agination in Wenchuan Earthquake. W ith high resolution SAR mi ageswe detecte a greatdealof landslides and landslide lakes. Those giant catastrophic landslides reach very large size and scale. One of the largest landslideswe detecte has total area of7 km2and fly distance of4 km. They fly from one side of the riverbank to the opposite bank. It ishard to explain theirbe- havior and scalewith ordinary conceptof landslide. Moving such amountofmaterialneeds tremendous energy. DoesWen- chuan Earthquake provide such amountof energy? Why doesWenchuan Earthquake generate somany seismic secondary disasters? Certainly geosciences community needs further research to solve this puzzle. Themicrowave remote sensing division in Institute ofRemote Sensing Applicationsmade 7 reports on Tangjiashan landslide and Landslide Lake, Beichuan countywithmulti-temporalSAR mi ages, 7 reports on other landslides and land- slide lakes, 1 reporton building damage assessment for several counties, includingAnchang town, HuagaiTown, Mianzu City and LuojiangCity. All the reportswere delivered to central and localgovernment, ministries and rescue teams. This paper summaries thework thathas been done forWenchuan Earthquake. This paperpresents the SAR mi age interpretation on building damage assessment, landslide and landslide lakemoni- toring, especially their characteristics on SAR mi ages. The damaged building normally has no clear texture or shadow in contrastwith buildings in good conditions. Owing to the good stereoscopic sense ofSAR mi ages,we can identify the back scar, debris deposit, fly trace and measure the total area and the flying distance of a landslide. W ith continuously ac- quiredmulti-temporalSAR mi ages, including TerraSAR-X and COSMO-SkyMed satellite SAR mi ages,we can track the development of a landslide lake such asTangjiashan LandslideLake. Aswater level rising, the small towns such asXuan Ping, Zhicheng and village ShengKenziare inundated. TheXuan PingTown is finally totalunderwater. Many roads along the Jian Riverare inundated aswel.l The tailofTangjiashanLandslideLake extends toward upstream gradually, andwid- ens the riverchannelobviously. All the information extracted and evaluation delivered from SAR mi agesmade greatcontri- bution to the decisionmaking and rescue action.