2016 Kumamoto earthquakes explained

2016 Kumamoto earthquakes
Timestamp:2016-04-15 16:25:06
Anss-Url:us20005iis
Isc-Event:610289055
Map:Japan Shakemap 15 April 2016.jpg
Local-Time:01:25 JST (UTC+9)
Magnitude:7.0 [1]
7.3
Depth:10 km[2]
Fault:Futagawa-Hinagu fault zone
Type:Strike-slip
Affected:Kumamoto Prefecture, Kyushu, Japan
Pga:1.61 g (foreshock)
1580 Gal (foreshock)
1.83 g (mainshock)
1791 Gal (mainshock)
Foreshocks:6.2,
12:26:36 (UTC), 21:26:36 (JST)[3] [4] [5]
Casualties:277 dead, 2,809 injured [6]

The were a series of earthquakes,[1] including a magnitude 7.0 mainshock which struck at 01:25 JST on April 16, 2016 (16:25 UTC on April 15) beneath Kumamoto City of Kumamoto Prefecture in Kyushu Region, Japan, at a depth of about 10km (10miles),[7] and a foreshock earthquake with a magnitude 6.2 at 21:26 JST (12:26 UTC) on April 14, 2016, at a depth of about 11km (07miles).

In total, the two earthquakes killed 277 people[8] and injured 2,809 others, a majority of them indirectly,[6] [9] This earthquake sequence was the deadliest in Japan since the 2011 Tōhoku earthquake and tsunami,[10] until the 2024 Noto earthquake. Of these, 50 deaths were directly caused by the earthquake, 218 were caused by aggravation of injuries from the earthquake or aggravation of illnesses during evacuation, and 5 of the deaths caused by the heavy rains from June 19-25 were related to the earthquake.

Severe damage occurred in Kumamoto and Ōita Prefectures, with numerous structures collapsing and catching fire. More than 44,000 people were evacuated from their homes due to the disaster.

Tectonic setting

Kumamoto Prefecture lies at the southern end of the Japan Median Tectonic Line, Japan's longest, where a system of active faults forks in two directions at the Beppu-Haneyama Fault Zone.[11] Specifically, the series of quakes ruptured the 81-km-long Hinagu Fault and 64-km-long Futagawa Fault to its north, as well as lesser but discernable interaction with the farther flung Beppu-Haneyama Fault Zone.[12] A 27-km section of the Futagawa Fault Zone slid 3.5 meters.[13] The earthquakes are occurring along the Beppu–Shimabara graben,[14] with epicentres moving from west to east over time.[15]

Around 08:30 local time on 16 April, Mount Aso saw a small-scale eruption with ash billowing 100m (300feet) into the air; the eruption was not related to the earthquake.[16] [17] Mount Aso had already been active since before the earthquakes,[18] being under a Level 2 warning from the JMA since November 24, 2015.[19] [20]

Earthquakes

April 14 foreshock

Although the focus of the foreshock earthquake was 12km (07miles) beneath Mount Kinpo to the north-northwest of Kumamoto's city center, the worst-hit area was in the eastern Kumamoto suburb of Mashiki, where the foreshock earthquake's victims perished.[21] The earthquake was strongly felt as far north as Shimonoseki on southwestern Honshu, and as far south as the city of Kirishima in Kagoshima Prefecture.[22] In the following hours, there were at least 11 aftershocks of at least 4.5 magnitude, one of which was a magnitude 6;[23] more than 140 aftershocks were registered within two days.[24] It was the first earthquake to occur on the island of Kyushu to register as a 7 on the Japan Meteorological Agency seismic intensity scale.[25] [26] On April 15, the JMA officially labelled it (Japanese: 平成28年熊本地震, "Heisei 28 Kumamoto Earthquake")–Heisei 28 being the year 2016 on the Japanese calendar.[27]

Intensity! style="white-space:nowrap"
PrefectureLocation
7KumamotoMashiki
6-KumamotoKumamoto (Higashi-ku, Nishi-ku, Minami-ku), Tamana, Uki, Nishihara

April 16 mainshock

At 01:25 JST on April 16 (16:25 UTC, April 15), a 7.0 magnitude earthquake, under Higashi Ward of Kumamoto City in the Kyushu Region in southwest Japan, occurred as the result of strike-slip faulting at shallow depth. Significant additional damage occurred in those areas of Kumamoto Prefecture recovering from the April 14 earthquake, with strong tremors and damage also recorded as far east as the city of Beppu in Ōita Prefecture.[28] It was also felt as far away as Busan, South Korea, with an intensity of MMI III.[29] A tsunami advisory was issued at 01:27 JST for areas along the Ariake Sea and Yatsushiro Sea, with the wave height forecast at 0.2to,[30] but was lifted less than an hour later at 02:14 JST.[31]

Intensity! style="white-space:nowrap"
PrefectureLocation
7Kumamoto
6+KumamotoMinamiaso, Kumamoto (Chūō-ku, Higashi-ku, Nishi-ku), Kikuchi, Uto, Uki, Koshi, Ozu, Kashima
6-KumamotoAso, Kumamoto (Minami-ku, Kita-ku), Yatsushiro, Tamana, Misato, Nagomi, Kikuyo, Mifune, Yamato, Hikawa, Kamiamakusa, Amakusa
Oita

Aftershocks

The following is a list of major aftershocks that have occurred in Kumamoto Prefecture since April 14, 2016.

Japan TimeMagnitudeIntensityComment
2016-04-14 21:26Mj6.5, Mw6.27Foreshocks
2016-04-14 22:07Mj5.86-
2016-04-15 00:03Mj6.46+
2016-04-16 01:25Mj7.3, Mw7.07Mainshock
2016-04-16 01:45Mj5.96-Aftershocks
2016-04-16 03:03Mj5.95+
2016-04-16 03:55Mj5.86+
2016-04-18 20:41Mj5.85+
2016-04-19 17:52Mj5.55+

Damage and casualties

April 14 foreshock

At least nine people died and 1,108 more were injured by the April 14 foreshock.[24] The roof and exterior walls of Kumamoto Castle sustained damage.[32] The castle's shachihoko were also destroyed.[33] Service on the Kyushu Shinkansen was suspended after a train derailed due.[34] The foreshock displaced an estimated 44,000 people and collapsed at least 19 homes.[35] Merchandaise were knocked off shelves in stores. Fires broke out and landslides severely damaged roads.[36]

April 16 mainshock

At least 277 people were killed and 2,809 others were injured by the mainshock, including many indirectly.[8] [6] [37] Of these, 50 deaths were directly caused by the earthquake, 218 were [38] caused by aggravation of injuries from the earthquake or aggravation of illnesses during evacuation, and 5 of the deaths caused by the heavy rains from June 19-25 were related to the earthquake.[39] Across Kumamoto Prefecture, 8,657 houses were completely destroyed, 34,491 were partially destroyed and 155,095 others, as well as 467 public buildings and 12,857 structures of unspecified use, were damaged, including 270 houses which were affected by flooding. Three people were killed and 34 others were injured in Oita Prefecture, where 10 houses collapsed, 222 were severely damaged and 8,110 others were partially damaged. In Fukuoka Prefecture, 17 people were injured and 255 houses were damaged, four of them severely, while 13 people were injured and one house was damaged in Saga Prefecture. Eight people were injured and 41 houses were damaged in Miyazaki Prefecture, two of them severely, with damage also recorded in Yamaguchi and Nagasaki Prefectures.[39]

As a result of the mainshock, the entirety of Kumamoto city was left without water.[40] All residents of Nishihara Village in Kumamoto Prefecture were evacuated over fears that a nearby dam could collapse.[40] Kumamoto Airport was also closed to all but emergency flights, and service on the Kyushu Shinkansen was suspended after a train derailed due to the earthquake.[41] Numerous structures collapsed or caught fire as a result of the earthquake. Government officials estimated more than 1,000 buildings had been seriously damaged, with 90 destroyed.[42] A 500-bed hospital in Kumamoto City was knocked off its foundations, forcing the evacuation of all patients,[24] and a natural gas leak prompted Saibu Gas to turn off supplies to multiple homes in the city.[26]

Numerous landslides took place across the mountains of Kyushu, rendering roads impassable,[30] [43] The of the Japan National Route 325 in Minamiaso collapsed into the Kurokawa river.[44] A rockslide blocked the entirety of the four-lane expressway close to the fallen bridge, leaving a large scar that ran almost completely up the hill that suffered the rockslide.

The Aso Shrine was also heavily damaged in the earthquake. The shrine's rōmon (tower gate), officially classified as an Important Cultural Property by the Japanese government, and the haiden (worshiping hall) both completely collapsed.[45] Kumamoto Castle, another Important Cultural Property sustained damage to its roof and exterior buildings and walls because of the earthquakes and associated aftershocks.[46] Several of the castle's shachihoko ornaments were destroyed,[47] and a large number of kawara tiles also fell from the roof. Other historical buildings such as Janes' Residence, the first western-style house built in Kumamoto (dating from 1871)[48] were also totally destroyed.[49] The former registered Cultural Asset was initially located in the grounds of Kumamoto Castle, but was later relocated near Suizen-ji Jōju-en.

Early estimates of the economic costs of the damage range from $5.5 billion to $7.5 billion, with insured property losses estimated to be between $800 million to $1.2 billion, according to Risk Management Solutions or between $1.7 billion to $2.9 billion, according to Guy Carpenter.[50] Through the first half of 2016, about $3.2 billion of claims for damage to residential dwellings were paid out by insurance companies, according to data from the General Insurance Association of Japan.[51]

Aftermath

Kumamoto Prefectural Police received more than 300 calls, while Ōita Prefectural Police took 100 calls.[52] More than 91,700 people were evacuated. An additional 15,000 soldiers from the Japan Self-Defense Forces joined relief efforts following the earthquake.[53] By April 16, more than 44,000 people were evacuated from the hardest-hit areas.[30] Prime Minister Shinzō Abe mobilized 3,000 personnel of the Japan Self-Defense Forces to assist local authorities with search and rescue and recovery efforts.[30] By April 18, the number of people seeking shelter had risen to 180,000, while at least eight people remained missing in a landslide caused by the earthquake.

See also

References

Citations

External links

Notes and References

  1. Web site: M7.0 – 1km WSW of Kumamoto-shi, Japan . United States Geological Survey. 2016-04-15.
  2. Web site: M7.0 – 1km WSW of Kumamoto-shi, Japan. earthquake.usgs.gov. 16 April 2016.
  3. Web site: http://www.jma.go.jp/jma/press/1604/14a/201604142330.html . ja:平成28年4月14日21時26分頃の熊本県熊本地方の地震について . About the earthquake in the Kumamoto area of Kumamoto Prefecture, around 21:26, April 14, 2016 . . 2016-04-14 . 2016-04-15 . ja.
  4. Web site: http://www.data.jma.go.jp/svd/eew/data/nc/pub_hist/2016/04/20160414212638/content/content_out.html . ja:=緊急地震速報の内容 . The contents of the Earthquake Early Warning . . 2016-04-14 . 2016-04-15 . ja.
  5. Web site: M6.2 – 7km SW of Ueki, Japan . United States Geological Survey. 2016-04-15.
  6. Achour . N. . Miyajima . M. . 2020 . Post-earthquake hospital functionality evaluation: The case of Kumamoto Earthquake 2016 . Earthquake Spectra . 36 . 4 . 1670–1694 . 10.1177/8755293020926180. 2020EarSp..36.1670A . free .
  7. Web site: M7.0 – 1km WSW of Kumamoto-shi, Japan. USGS Earthquake Hazards Program. 15 April 2016.
  8. News: ja:=8年前の熊本地震「災害関連死」新たに1人が認定 死者277人に . One more person recognized as a "disaster-related death" from the Kumamoto earthquake 8 years ago, bringing death toll to 277 . https://www3.nhk.or.jp/news/html/20240814/k10014548951000.html . 14 August 2024 . NHKニュース . 14 August 2024.
  9. Web site: Fire and Disaster Management Agency . 熊本県熊本地方を震源とする地震(第121報) . Japan Meteorological Agency . 25 March 2021 . Japanese . 12 April 2019.
  10. News: Lawson . Hugh . Japan's major earthquakes since the 1995 Kobe disaster . 2 January 2024 . Reuters . 2 January 2024 . Lisa Shumaker.
  11. Web site: Unusual quake cluster worries Japan – Nikkei Asian Review . asia.nikkei.com . 12 January 2022 . https://web.archive.org/web/20160419024755/https://asia.nikkei.com/Features/Kyushu-earthquakes/Unusual-quake-cluster-worries-Japan . 19 April 2016 . dead.
  12. Web site: Chain reaction activated separate fault zone in 2nd huge quake – Japan Today: Japan News and Discussion. April 19, 2016. https://web.archive.org/web/20160417133943/http://www.japantoday.com/category/national/view/chain-reaction-activated-separate-fault-zone-in-2nd-huge-earthquake. April 17, 2016. dead. mdy-all.
  13. asia.nikkei.com/Features/Kyushu-earthquakes/Unusual-quake-cluster-worries-Japan
  14. Web site: Kyushu. Introduction to the Landforms and Geology of Japan. GLGArcs. 16 April 2016. https://web.archive.org/web/20160410204010/http://www.glgarcs.rgr.jp/intro/kys.html. April 10, 2016. dead. mdy-all.
  15. Web site: Seismic activity could move east, trigger quakes in active faults. The Asahi Shimbun. The Asahi Shimbun Company. 16 April 2016.
  16. News: The Japan Times. Reuters. April 16, 2016. April 16, 2016. Small eruption seen on Mount Aso after latest quakes.
  17. News: Otake. Tomoko. Aoki. Mizuho. Yoshida. Reiji. Questions and answers: The Kumamoto earthquakes. 21 April 2016. The Japan Times Online. 18 April 2016. en.
  18. News: Small-scale eruption at Mt. Aso in Kumamoto not related to quakes: volcanologist. 16 April 2016. Mainichi, Japan. The Mainichi Newspapers. April 16, 2016.
  19. Web site: Volcanic Warnings. Japan Meteorological Agency. 16 April 2016.
  20. Web site: Aso Volcanic Warning Level Lowered to Level 2, Entry Allowed Up to Mt. Aso Rope Way Asosan-Nishi Station. Kumamoto Prefectural Tourist Board. 熊本県観光課. 16 April 2016.
  21. News: At Least 10 Dead, More Than 800 Injured in Japan 6.5-Magnitude Earthquake. ABC News. 2016-04-15. 2016-04-15.
  22. News: http://www.jma.go.jp/jp/quake/20160414213615395-142126.html. ja:地震情報(各地の震度に関する情報). Earthquake Information: Information on the Seismic Activity in Affected Areas. Japan Meteorological Agency. ja. 2016-04-14. 2016-04-15. https://web.archive.org/web/20160414131023/http://www.jma.go.jp/jp/quake/20160414213615395-142126.html. April 14, 2016. dead. mdy-all.
  23. Web site: 6.2 Magnitude Earthquake Hits Southern Japan, Killing 2; Homes Collapse, 45 Injured.
  24. News: Doug Stanglin. USA Today. April 16, 2016. April 16, 2016. Hospital evacuated after major quake rocks Japanese island.
  25. News: More aftershocks feared after strong quake in southwestern Japan. Nikkei Asian Review. 2016-04-15. 2016-04-15. https://web.archive.org/web/20160416123837/http://asia.nikkei.com/Japan-Update/More-aftershocks-feared-after-strong-quake-in-southwestern-Japan. April 16, 2016. dead. mdy-all.
  26. News: Daisuke Kikuchi. The Japan Times. April 15, 2016. April 15, 2016. Kumamoto residents pick up the pieces following Kyushu's strongest quake.
  27. http://www.jma.go.jp/jma/en/2016_Kumamoto_Earthquake/2016_Kumamoto_Earthquake.html The 2016 Kumamoto Earthquake –Portal –Earthquake Summary
  28. Web site: M 5.1 – 11km WSW of Beppu, Japan. earthquake.usgs.gov. 16 April 2016.
  29. Web site: Magnitude 3 Tremors Felt in Southern Region. April 16, 2016. April 17, 2016. https://web.archive.org/web/20160417105136/http://world.kbs.co.kr/english/news/news_Dm_detail.htm?No=118370. dead.
  30. News: Don Melvin. Greg Botelho. Ray Sanchez. CNN. April 16, 2016. April 16, 2016. 7.0 quake strikes Japan; rescuers try to free residents.
  31. Web site: Japan Meteorological Agency Tsunami Warnings/Advisories, Tsunami Information. www.jma.go.jp. 17 April 2016.
  32. News: Quake damages roof, walls at Kumamoto Castle. Asahi Shimbun. 2016-04-15. 2016-04-15.
  33. News: 熊本城 地震で「しゃちほこ」なくなる ("Kumamoto Castle: The Earthquake Destroys the Castle's 'Sachihako'"). NHK. Japanese. 2016-04-15. 2016-04-15.
  34. News: Aftershocks rattle southwestern Japan after quake kills nine. Reuters. 2016-04-15. 2016-04-15.
  35. News: At Least 9 Dead, More Than 800 Injured in Japan 6.5-Magnitude Earthquake . 22 August 2024 . ABC News . 15 April 2016.
  36. News: Yan . Holly . Wakatsuki . Yoko . Armstrong . Paul . Japan earthquake kills nine; more aftershocks expected . 22 August 2024 . CNN News . 16 April 2016 . Tokyo.
  37. News: USN. April 18, 2016. April 18, 2016. Japanese Quake Death Toll Rises, U.S. Helps Deliver Aid.
  38. Web site: https://www.bousai.go.jp/taisaku/kyuujo/pdf/r01kaigi/siryo8.pdf. https://web.archive.org/web/20240308104743/https://www.bousai.go.jp/taisaku/kyuujo/pdf/r01kaigi/siryo8.pdf. ja:災害関連死について. 5. ja. Cabinet Office (Japan). 8 March 2024. 10 June 2024.
  39. Web site: https://www.fdma.go.jp/disaster/info/items/kumamoto.pdf. https://web.archive.org/web/20240415070037/https://www.fdma.go.jp/disaster/info/items/kumamoto.pdf. ja:熊本県熊本地方を震源とする地震(第121報). 3. ja. Fire and Disaster Management Agency. 12 April 2019. 15 April 2024. 10 June 2024.
  40. News: CBC News. April 16, 2016. April 14, 2016. 2nd Japanese earthquake leaves at least 3 dead, 400 injured.
  41. News: Aftershocks rattle southwestern Japan after quake kills nine. Reuters. 2016-04-15. 2016-04-15.
  42. Web site: April 17, 2016. April 17, 2016. Eleven people remain missing in southern Japan from two powerful earthquakes that killed 41 people. US News.
  43. Web site: Photos: Second Devastating Earthquake Hits Japan Triggering Landslides. NBC News. April 16, 2016 .
  44. News: Large road bridge collapses as new quake hits Kumamoto. Asahi Shimbun. 2016-04-16. 2016-04-16. December 21, 2016. https://web.archive.org/web/20161221133419/http://www.asahi.com/ajw/articles/AJ201604160029.html. dead.
  45. News: Designated national cultural asset at Aso Shrine collapses in Kumamoto quake. Mainichi Shimbun. 2016-04-16. 2016-04-16.
  46. News: Quake damages roof, walls at Kumamoto Castle. Asahi Shimbun. 2016-04-15. 2016-04-15. April 18, 2016. https://web.archive.org/web/20160418132717/http://www.asahi.com/ajw/articles/AJ201604150062.html. dead.
  47. News: http://www3.nhk.or.jp/news/html/20160415/k10010481881000.html. ja:熊本城 地震で「しゃちほこ」なくなる. Kumamoto Castle: The Earthquake Destroys the Castle's 'Sachihako'". NHK. ja. 2016-04-15. 2016-04-15. https://web.archive.org/web/20160415125009/http://www3.nhk.or.jp/news/html/20160415/k10010481881000.html. April 15, 2016. dead. mdy-all.
  48. Web site: The Janes' Residence Kumamoto . www.japanvisitor.com. 20 April 2016.
  49. News: 明治4年の西洋建築 「ジェーンズ邸」が倒壊. 20 April 2016. https://web.archive.org/web/20160415233329/http://www3.nhk.or.jp/news/html/20160416/k10010482961000.html. April 15, 2016. dead. mdy-all. ja.
  50. News: Hoffman. Mark. April's Japan earthquake insured damage could top $1 billion. 16 May 2016. Business Insurance. 12 May 2016.
  51. News: Kumamoto quake residential insurance claims paid hits $3.2bn. 1 July 2016. Artemis. Steve Evans Ltd.. 30 June 2016.
  52. News: Japan hit by 7.3-magnitude earthquake. 17 April 2016. The Guardian.
  53. News: Caroline Mortimer. The Independent. April 16, 2016. April 16, 2016. Japan earthquake: Tsunami alert after 7.3 tremor his south of country – 24 hours after 10 died in separate quake. https://ghostarchive.org/archive/20220501/https://www.independent.co.uk/news/world/asia/japan-earthquake-today-tsunami-alert-71-magnitude-ariake-sea-yatsushiro-a6986656.html . May 1, 2022 . subscription . live.