Ansei Earthquake

• Date: 1855/10/2
• Magnitude: 6.9
• Casualties: 130,000 killed, 100,000 injured
• Japanese: 安政地震 (Ansei jishin)

The Ansei Earthquake was a magnitude 6.9 earthquake which struck the shogunal capital of Edo in the 10th month, 1855. It caused extensive death and destruction, and is among the most famous natural disasters of the Edo period. The Ansei quake marks the emergence of the namazu, a mythical underground catfish believed to cause earthquakes as it thrashes about, as a popular superstition and visual symbol of earthquakes; though the concept of the namazu existed earlier, namazu-e (pictures of the namazu) in books and prints proliferated especially in the months and years following the Ansei Earthquake. It was the third of a series of major earthquakes following the Ansei-Tôkai Earthquake and Ansei-Nankai Earthquake which struck the Tôkai and Nankai regions in the 11th month the previous year.

The quake was a near-field earthquake, localized and focused shallowly beneath Edo. Roughly 130,000 people were killed, and another 100,000 injured. Roughly 10,000 homes are said to have been lost, along with all the daimyô yashiki (samurai lords' mansions) in Marunouchi; the stone walls of Edo castle were severely damaged as well. The famous Ueno Daibutsu (Great Buddha Statue) at Kan'ei-ji in Ueno was severely damaged by the earthquake as well, losing its head; today, only the face remains visible to visitors.

Many observed that the destruction seemed to be centered near the administrative buildings of the shogunate, inspiring many to suggest the earthquake was a sign of the gods' anger at the shogunate's order the previous year to gather up and melt down Buddhist temple bells from all over the country, in order to use the metal to forge cannon to ward off the Westerners.

References

• Maehira Fusaaki, "Edo bakufu to Ryûkyû shisetsu - Tôshôgû sankei wo chûshin ni" 江戸幕府と琉球使節～東照宮参詣を中心に, in Ryûkyû shisetsu, Edo he iku!, Okinawa Prefectural Museum (2009), 70.