Datum shift and/or trend difference following short gap in 1978.
Documentation added 2012-02-22
A massive earthquake magnitude 9.0 occurred at 14.46 JST (05.46 UTC) on Friday 11th March 2011 with the epicentre situated approx. 70km east of the Oshika Peninsula of Tohoku. It was the most powerful earthquake to strike Japan triggering a tsunamia with waves of up to 40.5m and travelling inland up to 10km.
Documentation added 2014-03-13
The GPS benchmark information has been downloaded from the SONEL website. GPS benchmark is P113 13.771m above RLR.
Documentation added 2019-02-12
Spike in dataset for May 2018 has been flagged.
Geographical Survey Institute Kitasato -1 Tsukuba-shi Ibaraki-ken 305