What is “SHIRASU”?
“SHIRASU” is a general term for the deposit of pyroclastic flow of volcanic ash found in South of Kyushu. It covers almost half of the Kagoshima prefecture (4,600 km2) with an average thickness of 60m.
The amount of deposits are estimated to be 75 billion m3, enough to fill the Tokyo Dome 60 000 times. Since it is not suitable for agriculture due too high drainage and scarce nutritive substances, and corrosion and mudslides easily happen at the time of heavy rain, it is regarded as an unwelcome troublesome material.