Crustal strain at Hanaore and Ohara observation wells following the earthquake had, as of 9 April, returned to variation tendencies that prevailed prior to the event. Hence crustal-strain variation described below was related to the earthquake of 16 March. Variation at Hanaore and Ohara observation wells was clearest at Hanaore where it was one digit larger than at Ohara. The post-earthquake decrease remarked at Ohara Observation Point may have been influenced by a rising underground water level.
Geological Survey of Japan