The 1707 Hōei earthquake and tsunami preceded an eruption of Mount Fuji.
The great Hōei earthquake struck Japan on 28 October 1707 and ruptured the major segments of the Nankai megathrust. Its tsunami and severe shaking affected wide areas of southwestern Japan, making it one of the country’s most destructive historical earthquakes.
Forty-nine days later, on 16 December 1707, Mount Fuji began its last known eruption. The eruption produced the Hōei crater on Fuji’s southeastern flank and spread ash over parts of the surrounding region. The close timing led historians and volcanologists to investigate whether the earthquake helped trigger the eruption.
The connection is plausible but not proven as a simple cause-and-effect sequence. A large earthquake can change stresses and pressures in a volcanic system, but Fuji’s magma chamber would also have needed to be near an eruptive threshold. Mount Unzen, Mount Ontake and Mount Aso are famous Japanese volcanoes, but none is the volcano associated with the Hōei earthquake’s aftermath.