Use of high-resolution FORMOSAT-2 satellite images for post-earthquake disaster assessment: a study following the 12 May 2008 Wenchuan Earthquake

A large earthquake struck Wenchuan County, China on 12 May 2008 and is one of the most severe natural disasters of recent decades that has changed the entire landscape of Wenchuan County. This paper presents a satellite image analysis of the landslide following the Wenchuan earthquake and its consequences, and demonstrates how remote sensing techniques can be used for civilian crisis-management purpose and disaster relief. Real-time high resolution 2-dimensional and 3-dimensional information on structural deformation of land areas, directional changes of rivers, creation of new lakes, and the water levels of rivers and lakes in the earthquake affected area have been provided using the FORMOSAT-2 and Satellite pour l'Observation de la Terre (SPOT)-5 satellite images. Satellite images taken before and after the 12 May 2008 Wenchuan Earthquake have been used for landslide investigation. Possible flooding and rupture of natural dams during the post-earthquake period have been indicated through the analysis of 3-dimensional images of FORMOSAT-2. Some rescue methods have been suggested for immediate recovery of the bereaved persons and to locate the corresponding area accurately using remote sensing techniques. Some precautionary measures have also been suggested to avoid further destruction. Comparisons of panchromatic and multispectral images of FORMOSAT-2 for a particular region have been made to quantify the location accuracy. Our results show that the real-time high-spatial resolution FORMOSAT-2 satellite images could be an efficient and useful resource for decision-makers to prepare rescue and post-event recovery operation plans, especially for some isolated earthquake areas where damage distribution is often very uneven and hard to reach in time.