[4] Megathrust earthquakes on this structure tend to occur in pairs, with a relatively short time gap between them.

[6] On the east side of the Izu Peninsula, Shimoda was hit by the tsunami one hour after the earthquake.

Diana, the flagship of a visiting Russian admiral, Putyatin, in Japan to negotiate what would become the Treaty of Shimoda, was spun round 42 times on its moorings and was so badly damaged that it sank in a later storm.

[6] The rupture area, magnitude and epicenter have been estimated from seismic intensity measurements, information about tsunami arrival times and evidence of co-seismic uplift/subsidence.

This and the deposition of the unusual sand dome, with an estimated volume of 700,000 m3, is interpreted to have been caused by the effects of resonance in the V-shaped Suruga bay.