Land subsidence monitoring system in the southeast part of Kanto groundwater basin, Japan

The Kanto Plain, in Japan, is underlain by the Kanto groundwater basin. The basin is composed of Plio-Pleistocene marine sediments. Chiba Prefecture is located in the southeast part of the Kanto groundwater basin and, as of 2009, land subsidence has been monitored by 148 observation wells and 1159 benchmarks. Based on continuous monitoring, the mechanism of land subsidence is now reasonably well understood. The monitoring system is important for the sustainable use of groundwater.