Detection of Land Cover Changes before and after the 2016 Kumamoto Earthquake in Japan Using Remote Sensing for Evaluation of Environmental Impacts

Abstract

The land cover changes before and after the 2016 Kumamoto earthquake in Japan are detected using the Normalized Difference Vegetation Index (NDVI) calculated from satellite Sentinel-2A/2B images, and the methods and contents are described in this paper. The land cover change areas matched well with Google Map (aerial photographs), a high resolution latest map. In addition, the some areas where land cover changes spread over time were investigated by ground truths, and we have found that their cause is restoration works. To evaluate environmental impacts, we investigated the populations of the trapdoor spiders Heptathela higoensis in three study sites in the Aso area and Ozu Town in Kumamoto Prefecture. It is thought that the soil animal such as this spider receives the influence of the land cover changes directly. It is suggested that the changes of the spider populations can become an index to grasp the environmental changes before and after the earthquake quantitatively. The locations of the restoration works will not return to areas with high groundwater recharge capacity such as grasslands. If such restoration works spread, the people lived in the Aso and Kumamoto areas in Kumamoto Prefecture that rely on groundwater will have a serious problem in the future.