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2008 Iwate–Miyagi Nairiku earthquake

(Redirected from Iwate Miyagi Earthquake)
Not to be confused with July 2008 Iwate earthquake.

On 14 June, the 2008 Iwate earthquake struck the Tōhoku region of northeastern Honshū in Japan.[2] Japan Meteorological Agency (JMA) officially named this earthquake the Iwate–Miyagi Nairiku earthquake in 2008 (平成20年（2008年）岩手・宮城内陸地震).[3] This earthquake occurred in the south of the inland of Iwate Prefecture at 8:43 JST on June 14 (23:43 UTC on June 13).[4] The JMA magnitude was estimated at MJMA  7.2,[4] and the moment magnitude by USGS was at Mw 6.9.[5] The epicenter was located at 39°01.7′N 140°52.8′E / 39.0283°N 140.8800°E / 39.0283; 140.8800,[4] about 85 kilometres (55 mi) north of Sendai and about 385 kilometres (240 mi) north-northeast of Tokyo.[6]

Iwate–Miyagi Nairiku earthquake
岩手・宮城内陸地震
River channel blockage in the Sako River after the earthquake
USGS ShakeMap
2008 Iwate–Miyagi Nairiku earthquake is located in Japan
2008 Iwate–Miyagi Nairiku earthquake
UTC time2008-06-13 23:43:45
ISC event13377361
USGS-ANSSComCat
Local date14 June 2008 (2008-06-14)
Local time08:43 JST
Magnitude7.2 MJMA
6.9 Mw
Depth10 km (6 mi) (USGS)
8 km (5 mi) (JMA)
Epicenter39°01.7′N 140°52.8′E / 39.0283°N 140.8800°E / 39.0283; 140.8800
TypeReverse – Intraplate
Areas affectedIwate Prefecture, Tōhoku region, Japan
Max. intensityJMA 6+ (MMI VII)
Peak acceleration4.36 g (vector sum)
4278 Gal
Aftershocks483 felt aftershocks by 1 July (JMA)[1]
Largest: MJMA 5.7 on 14 June (9:20 JST)
Casualties12 dead, 436 injured (1 July 2007 at 17:00 JST)

The strongest shaking was measured in the cities of Ōshū (Iwate) and Kurihara (Miyagi), both of which were measured as "strong 6" on the Japan Meteorological Agency seismic intensity scale, shindo (震度, shindo).[2] Peak ground acceleration readings were high, with a maximum vector sum (3 component) value of 4,278 cm/s2 (4.36g).[7]

Intensity

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Seismic intensity (震度, Shindo) represents the strength of ground motion. JMA uses the scales of 0 to 7: 0, 1, 2, 3, 4, weak/strong 5, weak/strong 6, 7.

Prefecture Seismic intensities
Iwate 6+ 6- 5+ 5- 4 3 2
Miyagi 6+ 6- 5+ 5- 4 3
Akita 5+ 5- 4 3 2
Yamagata 5- 4 3 2
Fukushima 5- 4 3 2 1
Aomori 4 3 2 1
Ibaraki 4 3 2
Tochigi 4 3 2 1
Niigata 4 3 2 1
Hokkaidō 3 2 1
Gunma 3 2 1
Saitama 3 2 1
Chiba 3 2 1
Tokyo 3 2 1
Kanagawa 3 2 1
Yamanashi 3 2 1
Ishikawa 2 1
Nagano 2 1
Shizuoka 2 1
Aichi 1

Tremors were felt across a large area.[2]

Intensity Prefecture Location[8]
6+ Iwate Ōshū
Miyagi Kurihara
6- Miyagi Osaki
5+ Akita Yuzawa, Higashinaruse
Iwate Kitakami, Ichinoseki, Kanegasaki, Hiraizumi
Miyagi Kami, Wakuya, Tome, Misato, Natori, Sendai (Miyagino, Wakabayashi), Rifu
5- Akita Yokote, Ugo, Misato, Daisen
Iwate Tono, Fujisawa, Nishiwaga
Miyagi Shikama, Kakuda, Iwanuma, Zao, Ogawara, Kawasaki, Sendai (Aoba, Izumi), Ishinomaki, Ohira
Yamagata Mogami
Fukushima Shinchi

Tectonics

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According to the United States Geological Survey:[5]

The Mw 6.8 Honshu earthquake of June 13th 2008 occurred in a region of convergence between the Pacific plate and the Okhotsk section of the North American plate in northern Japan, where the Pacific plate is moving west-northwest with respect to North America at a rate of approximately 8.3 cm/yr. The hypocenter of the earthquake indicates shallow thrusting motion in the upper (Okhotsk) plate, above the subducting Pacific plate, which lies at approximately 80 km depth at this location.

The earthquake occurred in a region of upper-plate contraction, probably within the complicated tectonics of the Ou Backbone Range, known to have hosted several large earthquakes in historic times. The largest of these events occurred in 1896, approximately 70 km north of the June 13th event, and killed over 200 people in the local area.

Aftershocks

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According to JMA:[1][9][10]

Aftershocks of this earthquake were stronger than the Great Hanshin earthquake in 1995, but they happened much less frequently.

Over 200 aftershocks were observed in the first 24 hours, with about 400 in total over the first seven days. The largest ones (with Mj5.0 or greater) were

June 14, 9:20: Mj5.7: Max. seismic intensity reached Strong 5;
June 14, 12:27: Mj5.2: Max. seismic intensity reached 4;
June 16, 23:14: Mj5.3: Max. seismic intensity reached 4.

From June 21 to July 1, four to 12 aftershocks were observed each day, with maximum seismic intensities of 3.

Effects

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Riho Bridge collapsed after the earthquake
 
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Landslides

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Landslides triggered by this earthquake crushed structures, buried people, cut off access to certain roads, and isolated some rural communities.[11] Mud from landslides dammed up rivers to form lakes called "quake lakes" (せき止め湖, sekitomeko).[12]

By June 19, the Ministry of Land had identified fifteen quake lakes in Iwate and Miyagi prefectures,[13] and work crews began draining three of them which were at high risk of overflow or breach from rain or aftershocks.[14][15]

Human casualties

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By 17:50 JST, June 25, twelve people were confirmed dead and 358 injured, and ten still missing.[16]

  • In the city of Kurihara, Miyagi Pref., five people were buried in a landslide at a hot-spring inn called Komanoyu, which had stood on the mountainside of Mt. Kurikoma.[16][17] A woman aged 80 who had co-managed the inn with her husband, her 58-year-old son, a woman aged 75 who had worked at the inn, a 48-year-old tourism consultant, and an attendant of the Railway Museum aged 35 were all killed in the landslide.[18][19][20]
  • In the city of Kurihara, along Route 398, a landslide overwhelmed and killed three workers setting a rockfall containment net on a hillside.[16][21][22][23]
  • Also in the city of Kurihara, along Route 398, a 59-year-old man was killed when his car was carried away by a landslide and buried.[16][24]
  • At a dam construction site in the city of Ōshū, Iwate Pref., a worker aged 48 was struck by falling rocks and died.[16][21]
  • In the city of Ichinoseki, Iwate Pref., a person surprised by the tremor ran out into the road and was fatally struck by a truck.[16][21]
  • In the city of Iwaki, Fukushima Pref., near a fishing port, a person aged 55 was struck by falling rocks while fishing, fell into the sea, and drowned.[16][21]
  • In the city of Ōshū, a landslide caused a group of 20 people to become temporarily trapped in an overturned bus.[25] Eight of them were injured,[16] including one critically and five seriously.[26] The bus was running when overturned, and ten passengers escaped, prompted by the driver. Then an aftershock caused the bus to slip down slowly into a ravine until it was caught on some trees.[26] One of the passengers who had escaped walked down the road with a mobile phone until he was able to get a signal, and made an emergency call.[26]

Electric power supply

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No nuclear power plants were shut down following this earthquake[27] unlike the 2007 Chūetsu offshore earthquake quake. Some water was found to have splashed out of a reaction container in the Fukushima II Nuclear Power Plant possibly due to the tremor, but no radioactive material was released to the environment.[27][28]

Expressways and railways

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Expressways in Tōhoku region were closed in several sections, but all reopened by nighttime, barring traffic restrictions in one section for repair work.[29]

Some train services by JR East were suspended on Shinkansen and local lines, and resumed on the following day from the first scheduled trains.[30]

On Tōhoku Shinkansen, all running trains, about 20, were stopped by an earthquake detection system. Most were soon moved to the nearest stations.[31] However, about 2,000 passengers were temporarily trapped inside three trains[32] before being evacuated[31] up to nine and a half hours later,[33] because the trains were forced to stay in place while equipment inspections were carried out.[31]

Suspensions on Tōhoku, Akita, Yamagata Shinkansen and delays on Jōetsu, Nagano Shinkansen reportedly involved 117,000 passengers.[33] No trains derailed.[32]

See also

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References

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  1. ^ a b "「平成20年（2008年）岩手・宮城内陸地震」の余震回数" (PDF) (in Japanese). Japan Meteorological Agency]. 2 July 2008. Archived from the original (PDF) on 9 September 2008. Retrieved 2 July 2008.As of 2008-07-02 ( 5:00 JST).
  2. ^ a b c "Result of searching the database of felt earthquakes run by" (in Japanese). Japan Meteorological Agency. Archived from the original on 2011-03-22.
  3. ^ 2008年6月14日08時43分ころの岩手県内陸南部の地震について（第2報） (in Japanese). Japan Meteorological Agency. 2008-06-14. Archived from the original on 2011-03-22. Retrieved 2008-06-14.
  4. ^ a b c 「平成20年（2008年）岩手・宮城内陸地震」について（第４報） (in Japanese). Japan Meteorological Agency]. 2008-06-14. Archived from the original on 2011-03-22. Retrieved 2008-06-18.
  5. ^ a b "Magnitude 6.9 – EASTERN HONSHU, JAPAN". United States Geological Survey. 2008-06-14. Archived from the original on 22 September 2008. Retrieved 2008-06-18.
  6. ^ "Calculation tool" 距離と方位角の計算 (in Japanese). Geographical Survey Institute. Archived from the original on May 18, 2008. Retrieved 2008-06-18.
  7. ^ Masumi Yamada; et al. (July–August 2010). "Spatially Dense Velocity Structure Exploration in the Source Region of the Iwate-Miyagi Nairiku Earthquake". Seismological Research Letters. Seismological Society of America. pp. 597–604. Retrieved 21 March 2011.
  8. ^ "震度データベース検索". Japan Meteorological Agency. Retrieved 2021-07-05.
  9. ^ 「平成20 年（2008 年）岩手・宮城内陸地震」について（第８報） (PDF) (in Japanese). Japan Meteorological Agency. 2008-06-23. Retrieved 2008-07-01.
  10. ^ 「平成20 年（2008 年）岩手・宮城内陸地震」について（第９報） (PDF) (in Japanese). Japan Meteorological Agency]. 2008-06-26. Retrieved 2008-07-01.
  11. ^ "岩手・宮城内陸地震：６人死亡、１５５人負傷 不明１１人". The Mainichi Newspapers. 2008-06-14. Retrieved 20 June 2008.[permanent dead link‍]Last updated on 2008-06-15 (9:55 JST).
  12. ^ "Rush to drain 'quake lakes' in Tohoku". Mainichi Daily News. 2008-06-17. Archived from the original on 2013-02-18. Retrieved 2008-06-19.
  13. ^ 平成２０年岩手・宮城内陸地震により発生した河道閉塞（天然ダム）箇所について (in Japanese). Ministry of Land, Infrastructure, Transport and Tourism. 2008-06-19. Archived from the original on 28 June 2008. Retrieved 2008-06-19.
  14. ^ (This article will remain less than a month.) "Water being pumped out of quake lakes". NHK. 2008-06-19. Archived from the original on 2011-03-22. Retrieved 2008-06-19.
  15. ^ 宮城 せき止め湖仮排水路工事 (in Japanese). NHK. 2008-06-19. Retrieved 2008-06-19.[permanent dead link‍]
  16. ^ a b c d e f g h "平成２０年（２００８年）岩手・宮城内陸地震（第５１報）" (PDF). Fire and Disaster Management Agency. 2008-06-25. Retrieved 25 June 2008.[permanent dead link‍]As of 2008-06-25 (17:50 JST).
  17. ^ 秘湯の宿、瓦礫からうめき声…「駒ノ湯温泉」捜索難航 (in Japanese). The Yomiuri Shimbun. 2008-06-15. Archived from the original on 2008-06-18. Retrieved 2008-06-21.
  18. ^ 鉄道愛し、地域に尽くした 駒の湯温泉宿泊者 (in Japanese). The Asahi Shimbun Company. 2008-06-15. Archived from the original on 18 June 2008. Retrieved 2008-06-21.
  19. ^ 男性遺体は経営者の長男 駒の湯温泉 (in Japanese). The Asahi Shimbun Company. 2008-06-17. Archived from the original on 20 June 2008. Retrieved 2008-06-21.
  20. ^ 旅館手伝い女性の遺体を発見 駒の湯温泉で捜索隊 (in Japanese). The Asahi Shimbun Company. 2008-06-18. Archived from the original on 18 June 2008. Retrieved 2008-06-21.
  21. ^ a b c d 岩手・宮城地震 死者６人、行方不明１１人に (in Japanese). The Asahi Shimbun Company. 2008-06-14. Archived from the original on 17 June 2008. Retrieved 2008-06-21.
  22. ^ 作業員３人生き埋め ２人の死亡確認 栗原市花山 (in Japanese). The Asahi Shimbun Company. 2008-06-14. Archived from the original on 17 June 2008. Retrieved 2008-06-21.
  23. ^ １遺体発見 死者１２人・不明１０人に 岩手・宮城地震 (in Japanese). The Asahi Shimbun Company. 2008-06-21. Archived from the original on 4 August 2008. Retrieved 2008-06-21.
  24. ^ 対面の親族「実感ない」 湯浜温泉近くで死亡の男性 (in Japanese). The Asahi Shimbun Company. 2008-06-15. Archived from the original on 18 June 2008. Retrieved 2008-06-21.
  25. ^ "Japanese quake leaves at least six dead". United Press International, Inc. 2008-06-14. Retrieved 2008-06-19.
  26. ^ a b c "岩手・宮城内陸地震：バスが沢に転落、１人重体 奥州市". The Mainichi Newspapers. 2008-06-14. Retrieved 20 June 2008.[permanent dead link‍]Last updated on 2008-06-14 (21:04 JST).
  27. ^ a b "平成２０年岩手・宮城内陸地震被害情報（第８報）（６月１４日１７時００現在）" (PDF) (in Japanese). Nuclear and Industrial Safety Agency, Ministry of Economy, Trade and Industry. 2008-06-14. Archived (PDF) from the original on 24 June 2008. Retrieved 20 June 2008.As of 2008-06-14 (17:00 JST).
  28. ^ 岩手・宮城内陸地震：原発で水漏れ 外部に影響なし (in Japanese). The Mainichi Newspapers. 2008-06-15. Retrieved 2008-06-20. [dead link‍]
  29. ^ 平成20年 岩手・宮城内陸地震で発生した高速道路の被害状況等について（第8報 最終） (in Japanese). East Nippon Expressway Company Limited. 2008-06-14. Retrieved 2008-06-18.
  30. ^ "岩手・宮城地震：１５日始発からすべて運行…ＪＲ東日本". The Mainichi Newspapers. 2008-06-15. Retrieved 18 June 2008.[permanent dead link‍]Last updated on 2008-06-15 (21:05 JST).
  31. ^ a b c 【岩手・宮城内陸地震】「脱線せず」はＪＲの対策が奏功か 震源からの距離も影響？ (in Japanese). The Sankei Shimbun. 2008-06-14. Archived from the original on 2008-06-19. Retrieved 2008-06-18.
  32. ^ a b "2,000 passengers trapped in bullet trains, 20,000 households lose power after quake". Mainichi Daily News. 2008-06-14. Archived from the original on 2013-02-18. Retrieved 2008-06-18.
  33. ^ a b "岩手・宮城内陸地震：新幹線に９時間半閉じ込め 道路寸断". The Mainichi Newspapers. 2008-06-14. Retrieved 18 June 2008.[permanent dead link‍]Last updated on 2008-06-15 (0:27 JST).
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