The , was the third Ansei Great Earthquake, which occurred during the late-

Edo period The or is the period between 1603 and 1867 in the history of Japan, when Japan was under the rule of the Tokugawa shogunate and the country's 300 regional '' daimyo''. Emerging from the chaos of the Sengoku period, the Edo period was characteriz ...

. It occurred after the 1854 Nankai earthquake, which took place about a year prior. The earthquake occurred at 22:00 local time on 11 November. It had an

epicenter The epicenter, epicentre () or epicentrum in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates. Surface damage Before the instrumental pe ...

close to Edo (now Tokyo), causing considerable damage in the

Kantō region The is a geographical area of Honshu, the largest island of Japan. In a common definition, the region includes the Greater Tokyo Area and encompasses seven prefectures: Gunma, Tochigi, Ibaraki, Saitama, Tokyo, Chiba and Kanagawa. Slight ...

from the shaking and subsequent fires, with a death toll of 7,000–10,000 people and destroyed around 14,000 buildings. The earthquake had a magnitude of 7.0 on the surface wave magnitude scale and reached a maximum intensity of XI (''Extreme'') on the

Mercalli intensity scale The Modified Mercalli intensity scale (MM, MMI, or MCS), developed from Giuseppe Mercalli's Mercalli intensity scale of 1902, is a seismic intensity scale used for measuring the intensity of shaking produced by an earthquake. It measures the eff ...

. The earthquake triggered a minor

tsunami A tsunami ( ; from ja, 津波, lit=harbour wave, ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater explo ...

Tectonic setting

The Kanto area lies above a complex part of the

convergent boundaries A convergent boundary (also known as a destructive boundary) is an area on Earth where two or more lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction. The subduction zone can be defined by a ...

between the

subducting Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

and

Philippine Sea Plate The Philippine Sea Plate or the Philippine Plate is a tectonic plate comprising oceanic lithosphere that lies beneath the Philippine Sea, to the east of the Philippines. Most segments of the Philippines, including northern Luzon, are part of ...

s and the overriding

Eurasian Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago ...

and

North American Plate The North American Plate is a tectonic plate covering most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. With an area of , it is the Earth's second largest tectonic plate, behind the Pacific ...

s. Earthquakes with epicenters in the Kantō region may occur within the Eurasian Plate, at the Eurasian Plate/Philippine Sea Plate interface, within the Philippine Sea Plate, at the Philippine Sea Plate/North American Plate interface (under the

Sagami Trough The also Sagami Trench, Sagami Megathrust, or Sagami Subduction Zone is a long trough, which is the surface expression of the convergent plate boundary where the Philippine Sea Plate is being subducted under the Okhotsk Plate. It stretches from t ...

), at the Philippine Sea Plate/Pacific Plate interface (

Izu–Bonin–Mariana Arc The Izu–Bonin–Mariana (IBM) arc system is a plate tectonics, tectonic plate convergent boundary in Micronesia. The IBM arc system extends over 2800 km south from Tokyo, Japan, to beyond Guam, and includes the Izu Islands, the Bonin Island ...

), or within the Pacific Plate. In addition to this set of major plates it has been suggested that there is also a separate 25 km thick, 100 km wide body, a fragment of Pacific Plate

lithosphere A lithosphere () is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust (geology), crust and the portion of the upper mantle (geology), mantle that behaves elastically on time sca ...

. The cause of the 1855 earthquake is unknown; it is consistent with a rupture along the interface between the Eurasian and Philippine Sea Plates, adjacent to, and down dip from, the rupture that caused the

1923 Great Kantō earthquake The struck the Kantō Plain on the main Japanese island of Honshū at 11:58:44 JST (02:58:44 UTC) on Saturday, September 1, 1923. Varied accounts indicate the duration of the earthquake was between four and ten minutes. Extensive firestorms an ...

Damage

A total of about 50,000 houses and over 50 temples were either destroyed by the earthquake shaking or subsequent fires. An area of about 2.3 km² was burned down in Edo (now Tokyo). The earthquake's destruction and associated death toll were especially great for the time, as Ansei Edo was composed largely of plaster-and-tile structures that were resistant to fires but prone to tremors. In spite of Japan's long history with earthquakes, as of 1855 Edo had not experienced a major quake for about 154 years; in the minds of the citizenry, earthquakes were either a thing of the past or simply too unlikely to reasonably plan for. This lack of structural preparation, combined with the fact that most of the well-populated areas of Edo were built on former wetlands artificially filled in with unstable alluvial soil, left the city undefended from the massive force of the Ansei quake.Gregory Smits. ''Seismic Japan: The Long History and Continuing Legacy of the Ansei Edo Earthquake'
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Honolulu: University of Hawai'i Press, 2013. . The

Mito domain was a Japanese domain of the Edo period. It was associated with Hitachi Province in modern-day Ibaraki Prefecture.Tokugawa Nariaki Tokugawa Nariaki (徳川斉昭, April 4, 1800 – September 29, 1860) was a prominent Japanese ''daimyō'' who ruled the Mito Domain (now Ibaraki Prefecture) and contributed to the rise of nationalism and the Meiji Restoration. Biography C ...

; other casualties included Nariaki's son-in-law, Nanbu Toshigo, lord of Morioka domain. With the loss of its leader, internal strife within Mito intensified, leading to the fateful Sakurada Gate Incident in 1860.

Characteristics

The earthquake was followed by 78

aftershock In seismology, an aftershock is a smaller earthquake that follows a larger earthquake, in the same area of the main shock, caused as the displaced crust adjusts to the effects of the main shock. Large earthquakes can have hundreds to thousand ...

s in the first month.

Aftermath

Two days after the earthquake, prints began to appear, with more than 400 different types being available in the following weeks. Most of the prints depicted giant

catfish Catfish (or catfishes; order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the three largest species alive, ...

, a type of image known as

Namazu-e In Japanese mythology, the or is a giant underground catfish who causes earthquakes. The creature lives under the islands of Japan and is guarded by the god Takemikazuchi enshrined at Kashima, who restrains the catfish with a stone. When ...

. The significance being that earthquakes at the time were popularly attributed to the thrashing about of a mythological catfish under the earth, normally kept under control by the deity Kashima using a large rock. The number of prints produced during the 1855 earthquake was unprecedented and has been related to the political and social effects of the disaster. The prints show the people's anger with Kashima who became replaced by the solar deity

Amaterasu Amaterasu, also known as Amaterasu Ōmikami () or Ōhirume no Muchi no Kami (), is the goddess of the sun in Japanese mythology. One of the major deities (''kami'') of Shinto, she is also portrayed in Japan's earliest literary texts, the ''Kojik ...

. Some of the prints also depict the redistribution of wealth. The earthquake has been described as an act of ''yonaoshi'' or 'world rectification', in the light of the two

great Great may refer to: Descriptions or measurements * Great, a relative measurement in physical space, see Size * Greatness, being divine, majestic, superior, majestic, or transcendent People * List of people known as "the Great" *Artel Great (born ...

earthquakes An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, from ...

of 1854 and the arrival of Perry's

Black Ships The Black Ships (in ja, 黒船, translit=kurofune, Edo period term) was the name given to Western vessels arriving in Japan in the 16th and 19th centuries. In 1543 Portuguese initiated the first contacts, establishing a trade route linking G ...

in 1853.

Era of disaster

Three large earthquakes, the 1854 Ansei-Tōkai earthquake, 1854 Ansei-Nankai earthquake, and the 1855 Ansei Edo earthquake are collectively called the

Ansei great earthquakes The Ansei great earthquakes (安政の大地震, ''Ansei no Dai Jishin'') were a series of major earthquakes that struck Japan during the Ansei era (1854–1860): * The Ansei Tōkai quake ( ja, 安政東海地震, Ansei Tōkai Jishin, label=none) ...

(安政の大地震, ''Ansei no Dai Jishin''). Combining the effects of these disasters with a major cholera outbreak killing over 100,000 people, a fire at

Edo Castle is a flatland castle that was built in 1457 by Ōta Dōkan in Edo, Toshima District, Musashi Province. In modern times it is part of the Tokyo Imperial Palace in Chiyoda, Tokyo and is therefore also known as . Tokugawa Ieyasu established the ...

, and the

1858 Hietsu earthquake The was a doublet earthquake that took place on April 9, 1858 (according to the old Japanese calendar, February 26, Ansei 5). It most likely occurred on the Atotsugawa and Miboro faults, which connect the Amō Pass in Gifu Prefecture (in the part ...

, the

Ansei was a after ''Kaei'' and before ''Man'en''. This period spanned the years from November 1854 through March 1860. The reigning emperor was . Change of era * November 27, 1854 (): The new era name of ''Ansei'' (meaning "tranquil government") ...

era was one of quite catastrophic upheaval. Due to the cumulative effects of these disasters, the reign name was changed in 1860 to usher in a 'clean slate' and better "fortune".

Notes

References

* _____. (2007). in . Tokyo: Kawade Shobō Shinsha Publishers. * Gregory Smits. ''Seismic Japan: The Long History and Continuing Legacy of the Ansei Edo Earthquake'
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Honolulu: University of Hawai'i Press, 2013. . {{Authority control Edo Edo earthquake Edo 1855 tsunamis November 1855 events Earthquakes of the Edo period 1855 disasters in Japan