List of foreshocks and aftershocks of the 2011 Tōhoku earthquake

This is a list of foreshocks and aftershocks of the 2011 Tōhoku earthquake. Japan had experienced 900 aftershocks after the M9.1 earthquake on March 11, 2011 with about 60 aftershocks being over magnitude 6.0 and three over magnitude 7.0. For conciseness, only earthquakes with magnitudes greater than 7.0 or an intensity greater than lower-6 on the shindo scale are listed here. Mw refers to the moment magnitude scale, while Mjma, Mjma, or Mj refer to the Japan Meteorological Agency seismic intensity scale.

Map all coordinates using: OpenStreetMap 
Download coordinates as: KML
Visualization of intensity of aftershocks in the first few days
Map of aftershocks until March 14 (first 4 days)

ForeshocksEdit

Japan Time Magnitude Coordinates Depth Intensity (shindo)[1] Comment
2011-03-09 11:45 Mw 7.3, Mj 7.3[2] 38°25′26″N 142°50′10″E / 38.424°N 142.836°E / 38.424; 142.836 32 km[USGS 1] lower 5

The source was estimated to have a length of 28.7 km and a width of 53.2 km with a slip of 1.25 m.[3] Caused a 55 cm tsunami.[4]

2011-03-10 06:23 Mw 6.4, Mj 6.8 38°10′16″N 143°02′35″E / 38.171°N 143.043°E / 38.171; 143.043 9 km 4 Caused 11 cm Tsunami.[5]

Main shockEdit

Japan Time Magnitude Coordinates Depth Intensity (shindo)[1] Comment
2011-03-11 14:46 Mw 9.1, Mj 8.4[2] 38°19′19″N 142°22′08″E / 38.322°N 142.369°E / 38.322; 142.369 29 km[USGS 2] 7 19,747 deaths,[6] 2,556 people missing[7] tsunami, nuclear incidents.

AftershocksEdit

Japan Time Magnitude Coordinates Depth Intensity (shindo)[1] Comment
2011-03-11 15:08 Mj 7.4[1] 39°49′12″N 139°01′30″E / 39.82°N 139.025°E / 39.82; 139.025 32 km[1] lower 5
2011-03-11 15:15 Mw 7.9, Mj 7.6[1] 36°16′N 141°08′E / 36.27°N 141.14°E / 36.27; 141.14 43 km[USGS 3] upper 6
2011-03-11 15:25 Mw 7.7, Mj 7.5[1] 38°03′N 144°35′E / 38.05°N 144.59°E / 38.05; 144.59 19 km[USGS 4] 4
2011-04-07 23:32 Mw 7.1, Mj 7.2[1] 38°15′11″N 141°38′24″E / 38.253°N 141.640°E / 38.253; 141.640 42 km[USGS 5] upper 6 4 dead, 100+ injured, large scale power outage in Tōhoku region.[8][9]
2011-04-11 17:16 Mw 6.6, Mj 7.0[1] 37°00′25″N 140°28′37″E / 37.007°N 140.477°E / 37.007; 140.477 10 km[USGS 6] lower 6 6 dead, several injured, localized power outage and landslides in Iwaki, Fukushima.[10]
2011-04-12 14:07 Mj 6.4[1] 37°03′07″N 140°38′35″E / 37.052°N 140.643°E / 37.052; 140.643 15 km[1] lower 6
2011-07-10 09:57 Mw 7.0, Mj 7.3[1] 38°02′24″N 143°17′13″E / 38.040°N 143.287°E / 38.040; 143.287 23 km[USGS 7] 4 10 cm of tsunami in Sōma and Ōfunato.[11]
2012-12-07 17:18 Mw 7.3[1] 37°48′N 144°12′E / 37.8°N 144.2°E / 37.8; 144.2 49 km (JMA)[1]
36 km [USGS 8]
lower 5 Tsunami under 1 meter. Considered an aftershock by the National Earthquake Information Center in Colorado, USA.[12]
2013-10-26 02:10 Mw 7.1 37°10′12″N 144°39′54″E / 37.170°N 144.665°E / 37.170; 144.665 10 km [USGS 9] 4 Tsunami[13]
2016-11-22 05:59 Mw 6.9 37°23′35″N 141°23′13″E / 37.393°N 141.387°E / 37.393; 141.387 9 km lower 5
2021-02-13 23:07:49 Mw 7.1
MJMA 7.3
37°41′10″N 141°59′31″E / 37.686°N 141.992°E / 37.686; 141.992 35 km (USGS)
55 km (JMA)
upper 6 This earthquake resulted in at least 1 death and left at least 185 injured.[14] Serious damage was caused. There was no tsunami. It is believed that this was an aftershock of the earthquake almost 10 years to the exact date of the 2011 mainshock.[15]
2021-03-20 18:09:45 Mw 7.0
MJMA 6.9
38°28′30″N 141°36′25″E / 38.475°N 141.607°E / 38.475; 141.607 54 km (USGS)
60 km (JMA)
upper 5 This earthquake caused 8 minor injuries in Miyagi and Iwate Prefectures. Minor damage was reported in Miyagi Prefecture.[16]
2021-05-01 10:27:27[17] Mw 6.8 38°13′48″N 141°39′54″E / 38.230°N 141.665°E / 38.230; 141.665 47 km upper 5 Three people were injured by the strong shaking.[18]

Possibly related earthquakesEdit

The following earthquakes are possibly related to the 2011 Tōhoku earthquake. However, agreement toward the relationships has not been reached among the researchers.[19]

Japan Time Magnitude Coordinates Depth Intensity (shindo)[1] Comment
2011-03-12 03:59 Mw 6.3, Mj 6.7[1] 37°01′N 138°22′E / 37.02°N 138.36°E / 37.02; 138.36 8 km[1]
2 km[USGS 10]
upper 6 Possibly a triggered earthquake.[20][21]
2011-03-12 04:31 Mj 5.9[1] 36°56′53″N 138°34′19″E / 36.948°N 138.572°E / 36.948; 138.572 1 km[1] lower 6 Possibly a triggered earthquake.[21]
2011-03-12 05:42 Mj 6.3[1] 36°58′19″N 138°35′24″E / 36.972°N 138.59°E / 36.972; 138.59 2 km[1] lower 6 Possibly a triggered earthquake.[21]
2011-03-15 22:31 Mw 6.0, Mj 6.4[2] 35°17′N 138°32′E / 35.29°N 138.54°E / 35.29; 138.54 9 km[USGS 11] upper 6 50 injured. Power outage.[22] Near presumed location of magma chamber of Mount Fuji.
Sinistral strike-slip fault.[23] Possibly a triggered earthquake.[24]

ReferencesEdit

USGSEdit

  1. ^ Magnitude 7.2 – NEAR THE EAST COAST OF HONSHU, JAPAN Archived 2011-03-10 at the Wayback Machine. Earthquake.usgs.gov. Retrieved on 2011-04-12.
  2. ^ [1] Archived 2011-03-13 at the Wayback Machine. Earthquake.usgs.gov (2011-03-14). Retrieved on 2011-04-12.
  3. ^ : Preliminary Earthquake Report: NEAR THE EAST COAST OF HONSHU, JAPAN Archived 2011-04-12 at the Wayback Machine, USGS Earthquake Hazards Program (2011-03-11). Retrieved on 2011-04-12.
  4. ^ USGS Earthquake Hazards Program: Preliminary Earthquake Report: OFF THE EAST COAST OF HONSHU, JAPAN Archived 2011-04-12 at the Wayback Machine. Neic.usgs.gov (2011-03-11). Retrieved on 2011-04-12.
  5. ^ Magnitude 7.1 – NEAR THE EAST COAST OF HONSHU, JAPAN Archived 2011-04-14 at the Wayback Machine. Earthquake.usgs.gov. Retrieved on 2011-04-12.
  6. ^ Magnitude 6.6 – EASTERN HONSHU, JAPAN. Earthquake.usgs.gov. Retrieved on 2011-04-12.
  7. ^ "Magnitude 7.0 - Off the East Coast of Honshu, Japan 2011 July 10 00:57:12 UTC". Archived from the original on 2011-10-15. Retrieved 2017-07-23.
  8. ^ https://earthquake.usgs.gov/earthquakes/eventpage/usc000e5n4#summary
  9. ^ https://earthquake.usgs.gov/earthquakes/eventpage/usc000kn4n
  10. ^ USGS Earthquake Hazards Program: Preliminary Earthquake Report: NEAR THE WEST COAST OF HONSHU, JAPAN[permanent dead link]. Neic.usgs.gov. Retrieved on 2011-04-12.
  11. ^ USGS Earthquake Hazards Program: Preliminary Earthquake Report: EASTERN HONSHU, JAPAN[permanent dead link]. Neic.usgs.gov (2011-03-15). Retrieved on 2011-04-12.

OtherEdit

  1. ^ a b c d e f g h i j k l m n o p q r s t u 震度データベース検索 Archived 2013-02-13 at the Wayback Machine. Japan Meteorological Agency. Retrieved on 2013-02-18.
  2. ^ a b c 「平成23 年(2011 年)東北地方太平洋沖地震」について(第28 報)(Press Release), 25 March 2011. Published by Japan Meteorological Agency.
  3. ^ "Archived copy". Archived from the original on 2012-01-19. Retrieved 2011-12-02.CS1 maint: archived copy as title (link)
  4. ^ 日本付近で発生した主な被害地震(平成8年以降)」JMA, Access date March 5, 2017
  5. ^ 平成23年3月10日(06時23分)の三陸沖の地震で発表した津波注意報について JMA
  6. ^ "平成23年(2011年)東北地方太平洋沖地震(東日本大震災)について(第161報)(令和3年3月9日)" [Press release no. 161 of the 2011 Tohuku earthquake] (PDF). 総務省消防庁災害対策本部 [Fire and Disaster Management Agency]. Archived from the original (PDF) on 2021-03-09. Retrieved 2021-03-10. Page 31 of the PDF file.
  7. ^ "平成23年(2011年)東北地方太平洋沖地震(東日本大震災)について(第161報)(令和3年3月9日)" [Press release no. 161 of the 2011 Tohuku earthquake] (PDF). 総務省消防庁災害対策本部 [Fire and Disaster Management Agency]. Archived from the original (PDF) on 2021-03-09. Retrieved 2021-03-10. Page 31 of the PDF file.
  8. ^ asahi.com(朝日新聞社):東北の広域停電、完全復旧めどたたず 余震死者2人 – 東日本大震災. Asahi.com (2011-04-08). Retrieved on 2011-04-12.
  9. ^ 7日の地震 4人死亡141人けが NHKニュース Archived 2011-04-11 at the Wayback Machine. .nhk.or.jp. Retrieved on 2011-04-12.
  10. ^ CNN Wire Staff (11 April 2011). "At least 6 killed in new Japan earthquake". articles.cnn.com. CNN World News. Archived from the original on 2 June 2011. Retrieved 2011-04-23.
  11. ^ http://www.asahi.com/national/update/0710/TKY201107100080.html
  12. ^ Japanese Quake Stirs On-Air Alarm, but No Damage to Nuclear Plants Is Reported, New York Times
  13. ^ http://www.asahi.com/articles/TKY201310260033.html?ref=com_top6
  14. ^ "1st death confirmed in Feb. 13 northeastern Japan earthquake". Kyodo News. Kyodo News. 25 February 2021. Retrieved 25 February 2021.
  15. ^ "Large earthquake was an aftershock of 3/11 killer quake, expert says". The Japan Times. Retrieved 14 February 2021.
  16. ^ "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. Retrieved 21 March 2021.
  17. ^ "M 6.8 - 38 km ESE of Ishinomaki, Japan". United States Geological Survey. May 1, 2021. Retrieved 2021-05-01.
  18. ^ "6.8-Magnitude Quake Rattles Northeast Japan, No Tsunami Risk". Channels Television. Retrieved 2021-05-01.
  19. ^ 静岡東部の震度6強、東海地震誘発せず…専門家 : 科学 : YOMIURI ONLINE(読売新聞). Yomiuri.co.jp. Retrieved on 2011-04-12.
  20. ^ 2011年3月 東北地方太平洋沖地震 | 広報アウトリーチ室 Archived 2011-04-18 at WebCite. Outreach.eri.u-tokyo.ac.jp. Retrieved on 2011-04-12.
  21. ^ a b c 「平成23年(2011年)東北地方太平洋沖地震」について(第38報)(Press Release), 12 April 2011. Published by Japan Meteorological Agency. Retrieved on 2013-02-17.
  22. ^ http://www.pref.shizuoka.jp/kinkyu/documents/0315toubujisin5.pdf
  23. ^ 2011年3月15日静岡県東部の地震の評価. Jishin.go.jp. Retrieved on 2011-04-17.
  24. ^ 東日本沖巨大地震. Sk01.ed.shizuoka.ac.jp. Retrieved on 2011-04-12.

External linksEdit