Satellite imagery for landslide mapping in an earthquake-struck area

Abstract

This study examines the utilities of satellite imagery for landslide mapping in connection to a recent major earthquake event. The study area covers part of the Wenchuan County, Sichuan Province, China, approximately 30 km away from the epicenter of the Sichuan Earthquake that struck on 12 May 2008. Estimated at the magnitude of 7.9 on the Richter scale, this earthquake is cited as the 19th deadliest earthquake of all time. The Sichuan Earthquake and its aftershocks have triggered numerous landslides that were directly responsible for at least one-third of the overall casualties and widespread infrastructure damage. The primary data used are two satellite images acquired before and after the Sichuan Earthquake by Terra's Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Landsat 5 Thematic Mapper (TM). Georeferencing and radiometric normalization are conducted before further processing the satellite scenes. A Normalized Difference Vegetation Index (NDVI) image is computed from each of the images, and the NDVI change after the Earthquake is analyzed. It is found that the areas with a large NDVI decrease were largely related to earthquake-triggered landslide activities. This study demonstrates that satellite imagery can be quite useful to map the spatial distribution of earthquake-induced landslides quickly. © 2010 Springer Science+Business Media B.V.