Ansei great earthquakes
The Ansei Great Earthquakes (安政の大地震, Ansei no Dai Jishin) were a series of three major earthquakes that struck Japan during the Ansei era (1854-1860).
- The Ansei Tōkai Quake (安政東海地震, Ansei Tōkai Jishin) was an 8.4 magnitude earthquake which struck on December 23, 1854. The epicenter ranged from Suruga Bay to the deep ocean, and struck primarily in the Tōkai region, but destroyed houses as far away as in Edo. The accompanying tsunami caused damage along the entire coast from the Bōsō Peninsula in modern-day Chiba prefecture to Tosa province (modern-day Kōchi prefecture)[1].
- The Ansei Nankai Quake (安政南海地震, Ansei Nankai Jishin) was an 8.4 magnitude earthquake which struck on December 24, 1854. Over 10,000 people from the Tōkai region down to Kyushu were killed[1].
- The Ansei Edo Quake (安政江戸地震, Ansei Edo Jishin) was a 6.9 magnitude earthquake which struck Edo (modern-day Tokyo) on November 11, 1855. One hundred and twenty earthquakes and tremors in total were felt in Edo in 1854-55. The great earthquake struck after 10 o'clock in the evening; roughly 30 aftershocks continued until dawn. The epicenter was near the mouth of the Arakawa River. Records from the time indicate 6,641 deaths inside the city, and 2,759 injuries; much of the city was destroyed by fire, leading many people to stay in rural inns. Aftershocks continued for twenty days[1]. This quake was a particularly destructive deep thrust quake caused by a giant slab of rock stuck between the Philippine Plate and Pacific Plates.
The earthquake was blamed on a giant catfish (Namazu) thrashing about. Ukiyo-e prints depicting namazu became very popular around this time.
Other notable quakes to strike in the Ansei period include one in the Iga area, one which registered 7.4 on the Richter scale and struck Kyushu and Shikoku on November 7, 1854, and the 1858 Hietsu earthquake which struck the Hietsu area on April 9, 1858.