Tasks and problems involved in the handling of disaster waste upon April 2016 Kumamoto Earthquake, Japan

A series of earthquakes struck Kumamoto City area, SW Japan, including a magnitude 7.3 (mainshock) at 01:25 (Japan Standard Time: JST) on April 16 and a foreshock with a magnitude 6.5 at 21:26 JST on April 14, 2016. The earthquakes tremendously damaged the vulnerable structures and left a huge amount of disaster waste. Immediately after the earthquake, the Kumamoto Prefectural Government designated a number of locations for the erection of temporary waste storage facilities essentially in the vicinity of the most affected zones for the purpose of removing of the disaster waste from the damaged areas and their accumulation in the properly managed sites. The facilities provided sufficient ground for the temporary storage, handling, early sorting, and crushing of metallic objects, wood and its derivatives, glass, soil and rock, concrete, and household appliances. Mashiki Machi (town) and Nishihara Village were the nearest settlements to the epicenters of Kumamoto earthquakes that were severely damaged. The estimated amount of the disaster waste generated in Kumamoto Prefecture was about 2.89 million tons, the recycling and disposal of which must be completed within two years from the date of earthquake. Among various waste disposal facilities, the Nishihara Village storage facility was selected as the target for in-depth site investigation and disaster waste estimation. Drone survey was also conducted at different intervals at Nishihara Village facility with emphasis on wood debris. The drone technique employed in this survey demonstrated a reliable method for capturing high-resolution images from the selected site in a remarkably short period of time, and a relatively quick measure for estimating the amount of the disaster waste immediately after the disaster occurred.