Land subsidence observation using GPS on the Kujukuri Plain

Land subsidence on the Kujukuri Plain in Chiba Prefecture, Japan, where several companies develop natural gas and iodine, is likely caused by the pumping of brine. Therefore, the companies engaged in resource development have been involved in monitoring land subsidence using GPS in collaboration with Chiba University. The monitoring revealed that: (a) relatively significant subsidence is observed at GPS stations located in regions where natural gas and iodine developing activities are carried out, and that (b) GPS monitoring results indicate mostly the same trends as in levelling. We intend to continue monitoring land subsidence as a means to realize the voluntary management of land subsidence.