1896 June 15 UTC
Damage extreme. Tsunami. Over 27,000 deaths.
From Catalog of Significant Earthquakes, 2000 B.C. - 1979, published by World Data Center A for Solid Earth Geophysics, Report SE-27, July 1981.
"Fishermen twenty miles out to sea didn't notice the wave pass under their boats because it only had a
height at the time of about fifteen inches. They were totally unprepared for the devastation that awaited them
when they returned to the port of Sanriku. Twenty-eight thousand people were killed and 170 miles of
coastline were destroyed by the wave that had passed under them."
From "The Physics Behind the Wave."
"On June 15, 1896, nearly 22,000 Japanese lost their lives due to the most devastating tsunami in Japanese history. The tsunami,
which was generated by an earthquake off the coast of Sanriku, Japan, attained a height of 25 meters (80 feet), and instantly
swept away all houses and people when it reached land. The tsunami was also observed across the Pacific. In Hawaii, wharves
were demolished and several houses were swept away. In California, a 9.5 feet wave was observed, according to the San
Francisco Chronicle of June 16, 1896. This Sanriku tsunami served as an impetus for tsunami research in Japan. "
From Research Describes Origin of Devastating Tsunami.