1983 Sea of Japan earthquake

1983 earthquake and tsunami centered off the coast of Akita Prefecture, Japan

1983 Sea of Japan earthquake日本海中部地震

Felt intensities on the JMA scale, X marks epicenter

UTC time| 1983-05-26 02:59:59
ISC event| 577008
USGS-ANSS| ComCat
Local date| May 26, 1983 (1983-05-26)
Local time| 11:59:57
Duration| 60 seconds
Magnitude| 7.8 Mw[1]
Depth| 24 km (15 mi)
Epicenter| 40°27′43″N 139°06′07″E﻿ / ﻿40.462°N 139.102°E﻿ / 40.462; 139.102
Areas affected| Japan (Aomori Prefecture, Akita Prefecture)
Max. intensity| MMI VIII (Severe)

JMA 5+
Tsunami| yes
Casualties| 104 dead, 324 injured[2]
Boat damage from the tsunami, taken one day after the event

The 1983 Sea of Japan earthquake (Japanese: 日本海中部地震) occurred on May 26, 1983, at 11:59:57 local time (02:59:57 UTC). It had a magnitude of 7.8 on the moment magnitude scale. It occurred in the Sea of Japan, about 100 km west of the coast of Noshiro in Akita Prefecture, Japan. Out of the 104 fatalities, all but four were killed by the resulting tsunami, which struck communities along the coast, especially Aomori and Akita Prefectures and the east coast of Noto Peninsula. Images of the tsunami hitting the fishing harbor of Wajima on Noto Peninsula were broadcast on TV. The waves exceeded 10 meters (33 ft) in some areas. Three of the fatalities were along the east coast of South Korea (whether North Korea was affected is not known). The tsunami also hit Okushiri Island, the site of a more deadly tsunami 10 years later.

## Tectonic setting

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Main article: Eastern margin of the Sea of Japan

The northwestern side of Honshu lies on the southeastern margin of the Sea of Japan, an area of oceanic crust created by back-arc spreading from the late Oligocene to middle Miocene. The extensional tectonics associated with the spreading formed a series of N–S trending extensional faults and associated basins. Currently the area is being deformed by contractional tectonics, causing inversion of these earlier basins, forming anticlinal structures.[3] It has been suggested that the northwestern coast of Honshu represents an incipient subduction zone,[1] but there remain significant uncertainties about the existence of the Okhotsk microplate and the nature and precise location of its boundary in the Sea of Japan, if it does exist.[4][5]

## Earthquake

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The earthquake lasted for about 60 seconds. The focal mechanism indicates reverse faulting and the distribution of aftershocks is consistent with movement on a thrust plane dipping at 30° to the east. The rupture involved two separate faults, the more northerly of which trends NNW-SSE and the more southerly SSW-NNE. The rupture began on the southern fault before continuing on the northern fault after a delay of ten seconds.[6] The maximum perceived intensity was V on the JMA scale (VIII on the Mercalli intensity scale).[2]

## Tsunami

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Simulation of the tsunami propagating across the Sea of Japan

The first wave of the tsunami struck the coast about 12 minutes after the earthquake, with a maximum run-up height of 14.9 m (49 ft) recorded on the Oga Peninsula.[7] The initial models of the earthquake were unable to reproduce the short time interval between the shock and the first wave arrival at the coast. The possibility that the faults dipped to the west, which would have brought the tsunami source closer to the coast, was inconsistent with seismic data and slow aseismic slip on the southern fault immediately before the mainshock has been proposed as an explanation.[6]

Tsunami deposits associated with this earthquake have been recognised onshore, on the coast and in the Sea of Japan.[8] Offshore both mass failure deposits and turbidites have been observed that are dated to later than 1954 from high caesium-137 levels in the overlying sediments.[9]

## Damage

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Much of the earthquake damage was due to soil liquefaction, causing the collapse of houses and a number of road and rail accidents. The degree of liquefaction was the worst seen in Japan since the 1964 Niigata earthquake. The greatest effects were observed in areas underlain by loose Holocene aeolian and fluvial sands.[10] Four people were killed by the effects of the earthquake shaking.[2]

Tsunami warnings were issued 14 minutes after the earthquake, but many parts of the nearby coast were struck before any action could be taken.[7] Many people were struck by the first wave either on the shoreline or on offshore building sites and there were a hundred deaths. The tsunami caused widespread damage to coastal defences, which had been designed for storms rather than tsunamis. The tsunami reached the coast of South Korea about 1–1½ hours after the earthquake, causing the death of three people.[7]

## See also

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* List of earthquakes in 1983
* List of earthquakes in Japan

## References

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1. ^ a b Kanamori, H.; Astiz L. (1985). "The 1983 Akita-Oki Earthquake (Mw=7.8) and its Implications for Systematics of Subduction Earthquakes" (PDF). Earthquake Prediction Research. 3: 305–317\. Archived from the original (PDF) on 11 December 2013. Retrieved 21 June 2012.
2. ^ a b c National Geophysical Data Center. "Comments for the Significant Earthquake". Retrieved 21 June 2012.
3. ^ Sato, H.; Yoshida T.; Takaya I.; Sato T.; Ikeda Y. & Umino N. (2004). "Late Cenozoic tectonic development of the back arc region of central northern Honshu, Japan, revealed by recent deep seismic profiling". Journal of the Japanese Association for Petroleum Technology. 69 (2): 145–154\. doi:10.3720/japt.69.145. ISSN 0370-9868.
4. ^ Seno, Tetsuzo; Sakurai, Taro; Stein, Seth (1996). "Can the Okhotsk plate be discriminated from the North American plate?". Journal of Geophysical Research. 101 (B5): 11305–11315\. Bibcode:1996JGR...10111305S. doi:10.1029/96JB00532.
5. ^ Apel, E. V.; Bürgmann, R.; Steblov, G.; Vasilenko, N.; King, R.; Prytkov, A (2006), "Independent active microplate tectonics of northeast Asia from GPS velocities and block modeling", Geophysical Research Letters, 33 (L11303): L11303, Bibcode:2006GeoRL..3311303A, doi:10.1029/2006GL026077
6. ^ a b Shuto, N.; Chida K. & Imamura F. (1995). "Generation mechanism of the first wave of the Nihonkai-Chubu earthquake tsunami". In Tsuchiya Y. & Shuto N. (eds.). Tsunami: Progress in Prediction, Disaster Prevention, and Warning. Advances in Natural and Technological Hazards Research. Vol. 4\. Springer. pp. 37–53\. ISBN 978-0-7923-3483-5. Retrieved 21 June 2012.
7. ^ a b c National Geophysical Data Center. "Comments for the Tsunami Event". Retrieved 21 June 2012.
8. ^ National Geophysical Data Center. "Tsunami Event associated with Tsunami Deposits". Retrieved 21 June 2012.
9. ^ Nakajima, T.; Kanai Y. (2000). "Sedimentary features of seismoturbidites triggered by the 1983 and older historical earthquakes in the eastern margin of the Japan Sea". Sedimentary Geology. 135 (1–4): 1–19\. Bibcode:2000SedG..135....1N. doi:10.1016/S0037-0738(00)00059-2.1–4&rft.pages=1-19&rft.date=2000&rft_id=info:doi/10.1016/S0037-0738(00)00059-2&rft_id=info:bibcode/2000SedG..135....1N&rft.aulast=Nakajima&rft.aufirst=T.&rft.au=Kanai+Y.&rfr_id=info:sid/en.wikipedia.org:1983+Sea+of+Japan+earthquake" class="Z3988">
10. ^ Tohno, I.; Shamoto Y. (1986). "Liquefaction damage to the ground during the Nihonkai-Chubu (Japan Sea) earthquake in Aomori Prefecture, Tohoku, Japan" (PDF). Natural Disaster Science. 8 (1): 85–116. Retrieved 21 June 2012.

## External links

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* The International Seismological Centre has a bibliography and/or authoritative data for this event.

* v
* t
* e

← Earthquakes in 1983 →

* 1983 Popayán (5.5, March 31)
* Coalinga (6.5, May 2)
* Noshiro (7.8, May 26) †
* Biga (6.1, July 5)
* Luzon (6.5, August 17)
* Kopaonik (5.3, September 10)
* Borah Peak (6.9, October 28)
* Erzurum (6.9, October 30) † ‡
* Heze (5.7, November 7) †
* Kaoiki (6.7, November 16)
* Chagos Archipelago (7.7, November 30)
* Hindu Kush (7.4, December 30)
* Liège (4.7, November 8)

† indicates earthquake resulting in at least 30 deaths
‡ indicates the deadliest earthquake of the year

* v
* t
* e

Earthquakes in Japan

Historical|

* 679 Tsukushi
* 684 Hakuho
* 869 Jōgan
* 1026 Manju
* 1293 Kamakura
* 1361 Shōhei
* 1498 Meiō
* 1586 Tenshō
* 1596 Fushimi
* 1605 Keichō
* 1611 Aizu
* 1611 Sanriku
* 1662 Kanbun
* 1662 Hyūga-nada
* 1677 Bōsō
* 1703 Genroku
* 1707 Hōei
* 1741 Kampo
* 1751 Takada
* 1771 Great Yaeyama
* 1792 Unzen
* 1804 Kisakata
* 1828 Sanjō
* 1833 Shōnai
* 1847 Zenkoji
* 1854 Iga–Ueno
* 1854 Nankai
* 1854 Tōkai
* 1855 Edo
* 1858 Hietsu
* 1872 Hamada
* 1889 Kumamoto
* 1891 Mino–Owari
* 1894 Tokyo
* 1894 Shōnai
* 1896 Sanriku
* 1896 Rikuu

20th century|

* 1909 Anegawa
* 1911 Kikai Island
* 1914 Senboku
* 1922 Shimabara
* 1923 Great Kantō
* 1925 North Tajima
* 1927 North Tango
* 1930 North Izu
* 1933 Sanriku
* 1936 Miyagi
* 1939 Oga
* 1940 Shakotan
* 1941 Hyūga-nada
* 1943 Tottori
* 1944 Tōnankai
* 1945 Mikawa
* 1946 Nankai
* 1948 Fukui
* 1952 Tokachi
* 1961 North Mino
* 1963 Kuril Islands
* 1964 Niigata
* 1968 Ebino
* 1968 Hyūga-nada
* 1968 Tokachi
* 1973 Nemuro Peninsula
* 1974 Izu Peninsula
* 1978 Izu Ōshima
* 1978 Miyagi
* 1982 Urakawa
* 1983 Sea of Japan
* 1984 Nagano
* 1993 Kushiro
* 1993 Okushiri
* 1994 offshore Sanriku
* 1995 Hanshin
* 2000 Izu Islands
* 2000 Tottori

21st century|

* 2001 Geiyo
* 2003 Miyagi
* 2003 Tokachi
* 2004 Chūetsu
* 2005 Fukuoka
* 2005 Miyagi
* 2006 Kuril Islands
* 2007 Chūetsu
* 2007 Kuril Islands
* 2007 Noto
* 2008 Iwate–Miyagi
* 2008 Iwate
* 2009 Shizuoka
* 2011 Tōhoku
* 2011 Nagano
* 2011 Shizuoka
* 2011 Miyagi
* 2011 Fukushima
* 2012 Chiba
* 2012 Sanriku
* 2014 Nagano
* 2015 Ogasawara
* 2016 Kumamoto
* 2016 Tottori
* 2016 Fukushima
* 2018 Osaka
* 2018 Hokkaido Eastern Iburi
* 2019 Yamagata
* 2021 Fukushima
* 2021 Miyagi
* 2021 Chiba
* 2022 Fukushima
* 2023 Noto
* 2024 Noto
* 2024 Hyūga-nada

Related articles|

* Nankai megathrust earthquakes
* Tōkai earthquakes
* Tōnankai earthquakes
* Nankai earthquakes
* South Kantō earthquakes
* Matsushiro earthquake swarm

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