1854 Ansei-Nankai earthquake
Encyclopedia
The 1854 Ansei-Nankai earthquake occurred at about 16:00 local time on 24 December, 1854. It had a magnitude
of 8.4 and caused a damaging tsunami
. More than 30,000 buildings were completely destroyed and there were at least 3,000 casualties.
It was the second of the three Ansei Great Earthquakes; the 1854 Ansei-Tōkai earthquake
of similar size had hit the area the previous morning.
, which marks the subduction
of the Philippine Sea Plate beneath the Eurasian Plate
. Movement on this convergent plate boundary leads to many earthquakes, some of them of megathrust type
. The Nankai megathrust has five distinct segments (A-E) that can rupture independently, the segments have ruptured either singly or together repeatedly over the last 1300 years. Megathrust earthquakes on this structure tend to occur in pairs, with a relatively short time gap between them. In addition to the two events in 1854, there were similar earthquakes in 1944 and 1946. In each case the northeastern segment ruptured before the southwestern segment.
, because many people had left the coastal area following the large earthquake the previous day. In Hiro (now Hirogawa
), Goryo Hamaguchi
set fires using rice straw to help guide villagers to safety. This story was turned into "A living god" by the Greek-born writer Lafcadio Hearn
.
experienced shaking of 5 or more on the JMA scale
, with most of Shikoku and nearby coastal areas of Kansai
suffering an intensity of 6.
, 7.5 m in Kamikawaguchi (Japanese
: 上川口) of Kuroshio
, 7.2 m at Asakawa on the Tokushima
coast, 7.4 m at Usa
, 8.4 m at Ōnogō in the Susaki
area, 8.3 m at Kure on the Kōchi
coast and 5 m at both Hisayoshiura and Kaizuka on the coast of Ehime
.
Richter magnitude scale
The expression Richter magnitude scale refers to a number of ways to assign a single number to quantify the energy contained in an earthquake....
of 8.4 and caused a damaging tsunami
Tsunami
A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, typically an ocean or a large lake...
. More than 30,000 buildings were completely destroyed and there were at least 3,000 casualties.
It was the second of the three Ansei Great Earthquakes; the 1854 Ansei-Tōkai earthquake
1854 Ansei-Tōkai earthquake
The 1854 Ansei-Tōkai earthquake was the first of the Ansei Great Earthquakes . It occurred at about 09:00 local time on 23 December, 1854. It had a magnitude of 8.4 and caused a damaging tsunami...
of similar size had hit the area the previous morning.
Background
The southern coast of Honshu runs parallel to the Nankai TroughNankai Trough
The Nankai Trough is a submarine trough located south of Japan's island of Honshū, extending approximately 900 km offshore. In plate tectonics, the Nankai Trough marks a subduction zone that is caused by subduction of the Philippine Sea Plate beneath Japan, part of the Eurasian plate...
, which marks the subduction
Subduction
In geology, subduction is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate, sinking into the Earth's mantle, as the plates converge. These 3D regions of mantle downwellings are known as "Subduction Zones"...
of the Philippine Sea Plate beneath the Eurasian Plate
Eurasian Plate
The Eurasian Plate is a tectonic plate which includes most of the continent of Eurasia , with the notable exceptions of the Indian subcontinent, the Arabian subcontinent, and the area east of the Chersky Range in East Siberia...
. Movement on this convergent plate boundary leads to many earthquakes, some of them of megathrust type
Megathrust earthquake
Megathrust earthquakes occur at subduction zones at destructive plate boundaries , where one tectonic plate is forced under another. Due to the shallow dip of the plate boundary, which causes large sections to get stuck, these earthquakes are among the world's largest, with moment magnitudes ...
. The Nankai megathrust has five distinct segments (A-E) that can rupture independently, the segments have ruptured either singly or together repeatedly over the last 1300 years. Megathrust earthquakes on this structure tend to occur in pairs, with a relatively short time gap between them. In addition to the two events in 1854, there were similar earthquakes in 1944 and 1946. In each case the northeastern segment ruptured before the southwestern segment.
Damage
The damage due to the earthquake was severe with 5,000 houses being destroyed and 40,000 houses badly damaged. A further 6,000 homes were damaged by fire. The tsunami washed away a further 15,000 houses and a total of 3,000 people died from either the earthquake or the tsunami. The death toll associated with the tsunami was less than would be expected in comparison to the 1707 tsunami1707 Hōei earthquake
The 1707 Hōei earthquake, which occurred at 14:00 local time on October 28, 1707, was the largest in Japanese history until the 2011 Tōhoku earthquake surpassed it. It caused moderate to severe damage throughout southwestern Honshu, Shikoku and southeastern Kyūshū. The earthquake and the resulting...
, because many people had left the coastal area following the large earthquake the previous day. In Hiro (now Hirogawa
Hirogawa, Wakayama
is a town located in Arida District, Wakayama, Japan.As of 2003, the town has an estimated population of 8,221 and a density of 125.80 persons per km²...
), Goryo Hamaguchi
Goryo Hamaguchi
was the seventh business owner of current Yamasa Corporation in Japan He saved many lives of his fellow villagers of Hiro, Kii Province , when a massive tsunami struck the Kii Peninsula in 1854. He set fire to stacks of "Inamura" to use as landmarks and help him guide those villagers to safe place...
set fires using rice straw to help guide villagers to safety. This story was turned into "A living god" by the Greek-born writer Lafcadio Hearn
Lafcadio Hearn
Patrick Lafcadio Hearn , known also by the Japanese name , was an international writer, known best for his books about Japan, especially his collections of Japanese legends and ghost stories, such as Kwaidan: Stories and Studies of Strange Things...
.
Earthquake
Much of southwestern Honshu, Shikoku and KyūshūKyushu
is the third largest island of Japan and most southwesterly of its four main islands. Its alternate ancient names include , , and . The historical regional name is referred to Kyushu and its surrounding islands....
experienced shaking of 5 or more on the JMA scale
Japan Meteorological Agency seismic intensity scale
The Japan Meteorological Agency seismic intensity scale is a seismic scale used in Japan and Taiwan to measure the intensity of earthquakes. It is measured in units of...
, with most of Shikoku and nearby coastal areas of Kansai
Kansai
The or the lies in the southern-central region of Japan's main island Honshū. The region includes the prefectures of Mie, Nara, Wakayama, Kyoto, Osaka, Hyōgo, and Shiga. Depending on who makes the distinction, Fukui, Tokushima and even Tottori Prefecture are also included...
suffering an intensity of 6.
Tsunami
On Shikoku, the greatest inundation heights were 7.5 m in MugiMugi, Tokushima
is a town located in Kaifu District, Tokushima, Japan.As of 2003, the town has an estimated population of 5,540 and a density of 97.93 persons per km². The total area is 56.57 km².-External links:*...
, 7.5 m in Kamikawaguchi (Japanese
Japanese language
is a language spoken by over 130 million people in Japan and in Japanese emigrant communities. It is a member of the Japonic language family, which has a number of proposed relationships with other languages, none of which has gained wide acceptance among historical linguists .Japanese is an...
: 上川口) of Kuroshio
Kuroshio, Kochi
is a town located in Hata District, Kōchi, Japan. The town was formed on March 20, 2006 from the merger of the towns of Ōgata and Saga, both from Hata District. As of its formation but with 2003 population statistics, the town has an estimated population of 13,827 and a density of 73.4 persons per...
, 7.2 m at Asakawa on the Tokushima
Tokushima Prefecture
is a prefecture of Japan located on Shikoku island. The capital is the city of Tokushima.- Tokushima Prefecture and Myodo Prefecture :Long ago, Tokushima City belonged to a region known as Myōdō-gun...
coast, 7.4 m at Usa
Usa, Kochi
is an area of the city of Tosa, Kōchi Prefecture, Japan.Usa is famous for the exquisite Usa beach, Niyodo surfing and paragliding spots, tranquility of the town by the Pacific Ocean and as a home for the world famous Usa Marine Biological Institute...
, 8.4 m at Ōnogō in the Susaki
Susaki, Kochi
is a city located in Kōchi, Japan.As of 2003, the city had an estimated population of 26,960 and the density of . The total area is .The city was founded on October 1, 1954.-External links:* *...
area, 8.3 m at Kure on the Kōchi
Kochi Prefecture
is a prefecture of Japan located on the south coast of Shikoku. The capital is the city of Kōchi.- History :Prior to the Meiji Restoration, Kōchi was known as Tosa Province and was controlled by the Chosokabe clan in the Sengoku period and the Yamauchi family during the Edo period.- Geography...
coast and 5 m at both Hisayoshiura and Kaizuka on the coast of Ehime
Ehime Prefecture
is a prefecture in northwestern Shikoku, Japan. The capital is Matsuyama.-History:Until the Meiji Restoration, Ehime prefecture was known as Iyo Province...
.