=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 11-Jun-1991
Ayukawa             642/031 RLR(1963) is 9.6m below Attached BM
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 05-May-2009
From the dataset plot there appears to be a rising trend at this station.
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 22-Feb-2011
Profile buddy checks well with Ofunato II.
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 21-Feb-2012
A massive earthquake magnitude 9.0 occurred at 14:46 JST (05:46 UTC) on Friday 11th March 2011 with the epicenter approx. 70 km east of the Oshika Peninsula of Tohoku. It was the most powerful known earthquake ever to have hit Japan. The earthquake triggered tsunami waves up to 40.5m travelling up to 10km inland. As is obvious from the data plot the tide gauge site was badly effected. The data following the tsunami is flagged.
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 05-Apr-2022
Following review of data affected by the Tōhoku earthquake of 2011, all data has been flagged as good as GSI have recommenced levelling at the site. The station flag has been set to indicate the record needs to be treated with care, but the data appears to accurately reflect the earthquake's ongoing effect on local relative sea level.

