1707 Hōei earthquake

Geologic setting and rupture

The quake is interpreted as a megathrust event along the Nankai Trough, where the Philippine Sea Plate subducts beneath the Eurasian (or Amur) Plate. Evidence suggests multiple segments of the trough ruptured either nearly simultaneously or in rapid succession, a behavior that increases the event's size and reach. This faulting pattern is important for understanding long-term seismic cycles in the region and for modern hazard assessment.

Effects: shaking, tsunami and damage

Strong shaking caused collapsed structures, landslides and fires in urban and rural areas. Coastal areas experienced large tsunamis that swept inland, damaging ports, boats and low-lying villages. Eyewitness accounts and later surveys document widespread economic and social disruption, with large numbers of buildings destroyed and many communities left homeless.

Connection with Mount Fuji

An unusual and historically significant consequence was the eruption of Mount Fuji about seven weeks after the earthquake. Ashfall from that eruption affected wide areas and has been linked by many researchers to stress changes in the crust produced by the quake. The sequence—major earthquake followed by volcanic activity—has been cited when studying interactions between seismic and volcanic systems.

Historical importance and legacy

The Hōei event shaped contemporary disaster response, taxation and reconstruction records, which are valuable to modern historians and seismologists. It highlighted the potential for very large, multi-segment ruptures and long-range tsunamis along the Nankai margin. Today it is often referenced in risk models and preparedness planning for comparable future events.

Notable facts

• It affected a broad region of western and central Japan and generated tsunamis that reached many coastlines.
• The quake preceded the last large eruption of Mount Fuji, linking seismic and volcanic activity in the public memory.
• Scholars continue to study the Hōei earthquake to improve understanding of the Nankai Trough and earthquake clustering in Japan; see work on the Nankai Trough for more context.