Applicability of SAR to Marine Debris Surveillance After the Great East Japan Earthquake

After the Great East Japan earthquake on March 11, 2011, a huge amount of marine debris of more than 1.5 million tons was generated. It damaged the global marine environment, and reached the west coast of the United States around October 2012. As marine debris spreads with time, the chance of our observation was limited. To achieve an efficient time series analysis, we have to utilize complete advantage of the existing synthetic aperture radar (SAR) data with its wide range of observation conditions. In this study, an applicability of SAR to the tsunami disaster after the Great East Japan earthquake is discussed by estimating several key parameters such as total amount of marine debris and their vector velocities from SAR images obtained just after the earthquake under various observation conditions. Based on the analyses, we also discuss optimum marine debris monitoring by SAR to minimize the damage from tsunami disasters in future.