=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 11-Jun-1991
Oga                 647/096 RLR(1973) is 9.1m below BM Attach-23
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 15-Nov-1996
station rebuilt August-Decemebr 1994
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 17-Nov-2009
The relevant authority for this station is the Geographical Survey Institute. For some reason the data for 1998 was not downloaded from this authority. Data downloaded and entered 17.11.09.
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 22-Feb-2012
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 Tohoku. It was the most powerful earthquake to hit Japan triggering a tsunami with waves up to 40.5m andt travelling up to 10km inland.
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 13-Mar-2014
The GPS benchmark information has been downloaded from the SONEL website. GPS benchmark P104 is 14.092m above RLR.