Ground depression about 18cm accompanied the Niigata earthquake of June 16,1964
Documentation added 1991-06-11
Nezugaseki 647/091 RLR(1975) is 9.3m below BM Attach-16
Documentation added 2011-02-23
Buddy checked with Awa Sima. Profiles compare well particularly from the 1980's onwards. From May 1980 the benchmark still called Attached-16 but with a height of 8.961m above the datum was used. On the diagram this has been labelled Attach-16 (ii)
Documentation added 2012-02-21
A massive earthquake magnitude 9.0 occurred at 14.46 JST (05.46 UTC) on Friday 11th March 2011 with the epicentre approx. 70km east of the Oshika Peninsula of TTohoku. It was the most powerful known earthquake to hit Japan triggering a tsunami with waves up to 40.5m and travelling up to 10km inland.
Documentation added 2014-03-13
The GPS benchmark information has been downloaded from the SONEL website. GPS benchmark is P105 13.017m above RLR.
Geographical Survey Institute Kitasato -1 Tsukuba-shi Ibaraki-ken 305