The 1605 Keichō earthquake (Japanese: 慶長地震) occurred at about 20:00 local time on 3 February.

Movement on this convergent plate boundary leads to many earthquakes, some of them of megathrust type.

[6] In the 1605 event, there is evidence for two distinct earthquakes,[7] but they are not distinguished by all historical sources and some seismologists suggest that only the Nankai segment of the megathrust ruptured.

This has led seismologists to interpret this as a 'tsunami earthquake',[2] probably involving a slow rupture velocity causing little observed shaking while generating a large tsunami.

[14] The total number of casualties is uncertain as records are incomplete and contradictory,[9] but estimates are in the order of thousands.