On March 20, 2021, at 18:09 JST (09:09 UTC). The magnitude 6.9 or 7.0 earthquake struck offshore east of Tōhoku, Japan at a depth of 54.0 kilometers (33.6 mi) to 60 kilometers (37 mi).[3][4] It had a maximum JMA intensity of Shindo 5 while on the Mercalli intensity scale, it earned a rating of VII (Very strong).[5] Power outages and some slight damage in Miyagi was reported.[6]
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| UTC time | 2021-03-20 09:09:45 |
|---|---|
| ISC event | 620172298 |
| USGS-ANSS | ComCat |
| Local date | 20 March 2021 |
| Local time | 18:09:45 |
| Magnitude | 7.0 Mw (USGS) 6.9 MJMA (JMA) |
| Depth | 43.0 km (USGS) 60.0 km (JMA) |
| Epicenter | 38°28′30″N 141°36′25″E / 38.475°N 141.607°E |
| Fault | Japan Trench |
| Total damage | ¥63.4 billion ($550 million USD)[1] |
| Max. intensity | MMI VII (Very strong) JMA 5 |
| Casualties | 11 injured[2] |
A press release by the Japan Meteorological Agency stated that the earthquake was an aftershock of the 2011 Tōhoku earthquake and tsunami from ten years prior.[7][8]
Earthquake
editThe earthquake occurred as the result of thrust faulting near the subduction zone interface plate boundary between the Pacific and North America plates. Moment tensor solutions indicate that slip occurred either on a moderately dipping fault striking to the south, or a moderately dipping fault striking to the north-northeast, consistent with the east–west oriented compression expected in this region. At the location of this earthquake, the Pacific plate moves approximately westward relative to the North American plate at a velocity of 70 mm (2.8 in) per year, subducting beneath Japan at the Japan Trench and dipping to the west beneath Japan. The earthquake epicenter is located 70 km (43 mi) west of the epicenter of the March 2011 earthquake. It came just nine days after the tenth anniversary of the March 11, 2011 disaster, and just over a month since a MJMA 7.3 earthquake struck south of the March 20 event.[9]
Intensity
edit| Intensity | Prefecture | Location |
|---|---|---|
| 5 | Miyagi | Higashi-matsushima, Ishinomaki, Iwanuma, Matsushima, Misato, Osaki, Sendai, Tome, Wakuya, Zaō |
| 5− | Miyagi | Kakuda, Kawasaki, Kesennuma, Kurihara, Marumori, Minami, Natori, Ogawara, Ohira, Osata, Rifu, Sendai, Shibata, Watari, Yamomoto |
| Iwate | Ichinoseki, Ofunato, Sumita | |
| Fukushima | Futaba, Iitate, Kunimi, Minami, Namie, Okuma, Shinchi, Soma, Tamura |
Aftershocks
edit| Time (UTC) | Location | Magnitude | Depth (km) | MMI | Ref. |
|---|---|---|---|---|---|
| 2021-03-20 09:09:44 | 29 km east northeast of Ishinomaki | 7.0 | 43.0 | VII | [3] |
| 2021-03-20 09:34:58 | 47 km east southeast of Ishinomaki | 4.6 | 61.1 | - | [10] |
| 2021-03-20 16:41:17 | 49 km east southeast of Ishinomaki | 4.3 | 61.4 | - | [11] |
| 2021-04-03 12:58:27 | 30 km east southeast of Ōfunato | 4.6 | 41.2 | - | [12] |
| 2021-04-06 20:10:36 | 79 km east southeast of Ishinomaki | 4.2 | 45.1 | - | [13] |
| 2021-04-14 10:02:52 | 112 km east southeast of Ishinomaki | 4.3 | 39.6 | - | [14] |
| 2021-04-16 11:51:36 | 77 km east of Ishinomaki | 4.5 | 35.0 | - | [15] |
| 2021-04-18 00:29:12 | Near the east coast of Honshu | 5.6 | 51.7 | IV | [16] |
| 2021-04-18 00:29:25 | 49 km east southeast of Ishinomaki | 5.6 | 31.3 | IV | [17] |
| 2021-04-19 04:06:21 | 42 km south southeast of Ishinomaki | 4.9 | 55.1 | - | [18] |
Impact
editThe earthquake caused 11 minor injuries in the prefectures of Iwate, Miyagi and Fukushima.[19] Many of the injured were from Miyagi Prefecture. Four individuals from Sendai, Miyagi endured slight injuries. In Morioka, Iwate, a woman fell and suffered cuts.[20] Two elderly women aged 90 and 70 sustained minor head and shoulder injuries respectively when they were struck by furniture in Iwanuma, Miyagi.[21] There was one injury each reported in Date, Ishinomaki, Kesennuma and Tōno.[2]
Power outages were reported in some parts of Tohoku, forcing the suspension of bullet train services by the East Japan Railway Company.[22] In Shiogama, a six-meter (20 ft) wall supporting an inclined surface breached and collapsed during the earthquake.[20]
As a precaution, authorities from the Tohoku Electric Power utility shut down the Onagawa Nuclear Power Plant whilst the Tokyo Electric Power Company checked the conditions at the Fukushima Daiichi Nuclear Power Plant.[23] No radiation anomalies or changes in cooling water levels were detected at the power plant.[24]
A New Japan Pro Wrestling event in Sendai was temporarily halted mid-match due to the earthquake, which was captured by cameras recording the show. The event resumed approximately half an hour later after safety checks were carried out.[25]
Tsunami warning
editFollowing the earthquake, a tsunami advisory was issued at 18:11 JST for Miyagi Prefecture for waves of up to 1 meter (3 ft 3 in).[26] Despite the warnings, no tsunamis were observed; this is because the earthquake had ruptured a deeper portion of the subduction zone.[21][27] The tsunami advisory was then withdrawn at around 19:30 JST.[28]
Other events
editOn May 1, at 10:27 local time, a Mw 6.9 or MJMA 6.6 earthquake struck the southern tip of the Oshika Peninsula.[29] The earthquake had a depth of 47.3 km or 66 km and a maximum intensity of VI (Strong) or Shindo 5 upper.[30] According to the Japan Meteorological Survey, the earthquake would not be considered an aftershock of the 2011 Great East Japan earthquake as such announcements had ceased as of April 1 of 2021.[31] This is due to the decreasing rate of earthquakes which made it harder to determine if events like those of May 1 were actual aftershocks.[32] The agency also could not determine if this event was related to the earthquake of March 20.[33]
Minor damage including broken windows and a water pipe rupture was reported. The earthquake resulted in the suspension of Shinkansen services in the Tohoku region. In addition, three people sustained minor injuries. Two of the victims were using a hot spring at Onagawa Station when the quake struck and shattered window panels.[33] A third individual from Soma City in Fukushima Prefecture fell while shopping at a supermarket and was taken to a hospital for treatment.[33]
See also
edit
References
edit- ^ National Geophysical Data Center / World Data Service (NGDC/WDS) (2021). "Significant Earthquake Database" (Data Set). National Geophysical Data Center, NOAA. doi:10.7289/V5TD9V7K.
- ^ a b "宮城県沖を震源とする地震による被害及び 消防機関等の対応状況（第６報" (PDF). Fire and Disaster Management Agency Disaster Countermeasures Headquarters (in Japanese). 22 March 2021. Retrieved 22 March 2021.
- ^ a b "M 7.0 – 27 km ENE of Ishinomaki, Japan". USGS-ANSS. Retrieved 20 March 2021.
- ^ a b "Earthquake Information". Japan Meteorological Agency. Retrieved 20 March 2021.
- ^ a b "地震情報". tenki.jp (in Japanese). 20 March 2021. Retrieved 22 March 2021.
- ^ "Power outages hit part of Japan's Miyagi prefecture following quake, utility says". Reuters. 20 March 2021. Retrieved 20 March 2021.
- ^ "令和３年３月20日18時09分頃の宮城県沖の地震について －「平成23年（2011年）東北地方太平洋沖地震」について（第91報）－". Japan Meteorological Agency. Retrieved 21 March 2021.
- ^ "Seismic intensity 5 in Miyagi, M6.9 Shinkansen temporarily suspended" (in Japanese). Nikkei. 21 March 2021. Retrieved 21 March 2021.
- ^ "M7.3 Fukushima quake is aftershock of 2011 killer quake: expert". Kyodo News. Kyodo News. Retrieved 20 March 2021.
- ^ "M 4.6 – 47 km ESE of Ishinomaki, Japan". United States Geological Survey. Retrieved 18 April 2021.
- ^ "M 4.3 – 49 km ESE of Ishinomaki, Japan". United States Geological Survey. Retrieved 18 April 2021.
- ^ "M 4.6 – 30 km ESE of Ōfunato, Japan". United States Geological Survey. Retrieved 18 April 2021.
- ^ "M 4.2 – 79 km ESE of Ishinomaki, Japan". United States Geological Survey. Retrieved 18 April 2021.
- ^ "M 4.3 – 112 km ESE of Ishinomaki, Japan". United States Geological Survey. Retrieved 18 April 2021.
- ^ "M 4.5 – 77 km E of Ishinomaki, Japan". United States Geological Survey. Retrieved 18 April 2021.
- ^ "M 5.6 – near the east coast of Honshu, Japan". United States Geological Survey. Retrieved 18 April 2021.
- ^ "M 5.6 – 49 km ESE of Ishinomaki, Japan". United States Geological Survey. Retrieved 18 April 2021.
- ^ "M 4.9 – 42 km SSE of Ishinomaki, Japan". United States Geological Survey. Retrieved 19 April 2021.
- ^ Mari Yamaguchi (20 March 2021). "Strong quake shakes Japan; minor injuries, no major damage". United States: ABC News. Retrieved 20 March 2021.
- ^ a b "宮城で震度5強で計8人けが 1週間程度地震注意". All Nippon News. All Nippon News. 21 March 2021. Archived from the original on 21 March 2021. Retrieved 21 March 2021.
- ^ a b "宮城で震度５強 一時津波注意報、複数けが人―東日本大震災の余震・気象庁". Jiji. Jiji. 20 March 2021. Retrieved 22 March 2021.
- ^ Adela Suliman, Arata Yamamoto (20 March 2021). "Tsunami advisory issued after earthquake strikes off Japan's coast". NBC News. Retrieved 20 March 2021.
- ^ "Magnitude 7.2 earthquake strikes off northeast Japan, tsunami advisory issued: JMA". Al Arabiya. Reuters. 20 March 2021. Retrieved 21 March 2021.
- ^ Tokyo Electric Power Company Holdings, Inc (20 March 2021). "2021年3月20日地震情報（福島第一原子力発電所・福島第二原子力発電所関連）". TEPCO (in Japanese). Retrieved 22 March 2021.
- ^ "Earthquake temporarily halts NJPW Cup event in Sendai". 20 March 2021.
- ^ "気象庁｜統合地図ページ". Japan Meteorological Agency. Retrieved 20 March 2021.
- ^ "Magnitude 7.2 quake rocks northeastern Japan". The Japan Times. 20 March 2021. Archived from the original on 20 March 2021. Retrieved 20 March 2021.
- ^ "宮城県で震度5強 今後1週間程度は最大震度5強程度の地震に注意". NHK. NHK. 20 March 2021. Retrieved 21 March 2021.
- ^ "M 6.9 – 38 km ESE of Ishinomaki, Japan". United States Geological Survey. 1 May 2021. Retrieved 2 May 2021.
- ^ "Issued at 10:35 JST 01 May 2021 Earthquake and Seismic Intensity Information part 2". Japan Meteorological Agency. 1 May 2021. Retrieved 2 May 2021.
- ^ Rei Yamagishi (1 May 2021). "｢1週間程度、強い地震警戒」 気象庁、宮城の地震受け". Asahi Shimbun Digital. Retrieved 2 May 2021.
- ^ Ryo Yamagishi (1 April 2021). "JMA will stop calling temblors an aftershock of 3/11 quake". The Asahi Shimbun. Retrieved 2 May 2021.
- ^ a b c "地震でけが 計3人に 宮城や福島で" (in Japanese). NHK. 1 May 2021. Retrieved 2 May 2021.
External links
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