There is geological evidence , uncovered after the latest tsunami event of 2011 , of six catastrophic tsunamis hitting the Sanriku coast within 6000 years . Among them are : Some 22,000 people were killed in the Meiji Sanriku earthquake of 1896 . Most of the deaths were caused by tsunami . The disaster struck at 8:06 am on the morning of August 31 . The epicenter was determined to have been located at 39.5 Latitude/140 .6 Longitude , but no Richter Scale magnitude can be assessed on the basis of available data
Meiji Sanriku earthquake of 1896
1896 Sanriku earthquake
Seismicity of the Sanriku coast