The 1585 Aleutian Islands earthquake is the presumed source of a tsunami along the Sanriku coast of Japan on June 11, 1585, known only from vague historical accounts and oral traditions. The event was initially misdated to 1586, which led to it being associated with the deadly earthquakes in Peru and Japan of that year. The source earthquake was later determined by modern seismological studies to have originated near the Aleutian Islands in the North Pacific Ocean. Paleotsunami evidence from shoreline deposits and coral rocks in Hawaii suggest that the 1585 event was a large megathrust earthquake occurring on the Aleutian subduction zone with a moment magnitude (Mw ) as large as 9.25.