Author(s): Liqun Sun; Ji Chen
Linked Author(s): Ji Chen
Keywords: Wenchuan Earthquake; MODIS EVI; Vegetation Damage; Landslide; Remote Sensing
Abstract: The Wenchuan Earthquake in China occurred on 12 May 2008 resulted in massive life loss and numerous geotechnical disasters, such as landslides and quake lakes, in the mountainous region of Sichuan Province. Such geotechnical disasters significantly disturbed and damaged the vegetation cover over the region. This study develops a method for detecting the areas with severe vegetation damage caused by those quake-related geotechnical disasters and for monitoring the vegetation recovery after the earthquake. The new method makes use of one of the Moderate Resolution Imaging Spectroradiometer (MODIS) MOD13Q1 products, the enhanced vegetation index (EVI). Using a series of 16-day MODIS EVI maps at the 250 m spatial resolution from 2001 to 2012, this study delineates the regions with considerable abnormal EVI; for an optimal threshold, these delineated regions are normally consistent with the landslide areas. To further confirm those regions with vegetation damage, this study compares the observations from QuickBird, with 0. 6 m high resolution images after the disaster in Yingxiu Town. The confirmation result discloses that the severe vegetation damage is substantiated be “browning” of green vegetation in those regions. Moreover, according to the MODIS EVI time series data since May 2008, it is found that the vegetation damages have not been recovered in most of those regions yet. This study also investigates the topographic features of those vegetation-damaged regions. The ASTER 30-m DEM data are used to generate, slope map and aspect map for those regions. The results of those topographic features can be valuable for environmental prevention of similar vegetation damages.