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 magnitude scale.

Foreshocks Japan Time Magnitude Coordinates Depth Intensity (shindo)震度データベース検索 . Japan Meteorological Agency. Retrieved on 2013-02-18. Comment 2011-03-09 11:45 Mw 7.3, Mj 7.3「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. 32 kmMagnitude 7.2 – NEAR THE EAST COAST OF HONSHU, JAPAN . Earthquake.usgs.gov. Retrieved on 2011-04-12. 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. Caused a 55 cm tsunami.「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 2011-03-10 06:23 Mw 6.4, Mj 6.8 9 km 4 Caused an 11 cm tsunami.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

Main shock Japan Time Magnitude Coordinates Depth Intensity (shindo) Comment 2011-03-11 14:46 Mw 9.1,Mj 8.4 29 kmhttps://earthquake.usgs.gov/earthquakes/eventpage/official20110311054624120_30/executive . Earthquake.usgs.gov (2011-03-14). Retrieved on 2011-04-12. 7 , tsunami, nuclear incidents.

Aftershocks Japan Time Magnitude Coordinates Depth Intensity (shindo) Comment 2011-03-11 15:08 Mj 7.4 32 km 5- 2011-03-11 15:15 Mw 7.9, Mj 7.6 43 km: Preliminary Earthquake Report: NEAR THE EAST COAST OF HONSHU, JAPAN , USGS Earthquake Hazards Program (2011-03-11). Retrieved on 2011-04-12. 6+ 2011-03-11 15:25 Mw 7.7, Mj 7.5 19 kmUSGS Earthquake Hazards Program: Preliminary Earthquake Report: OFF THE EAST COAST OF HONSHU, JAPAN . Neic.usgs.gov (2011-03-11). Retrieved on 2011-04-12. 4 2011-04-07 23:32 Mw 7.1, Mj 7.2 42 kmMagnitude 7.1 – NEAR THE EAST COAST OF HONSHU, JAPAN . Earthquake.usgs.gov. Retrieved on 2011-04-12. 6+ 4 dead, 100+ injured, large scale power outage in Tōhoku region.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 2011-04-12.7日の地震 4人死亡141人けが NHKニュース . .nhk.or.jp. Retrieved on 2011-04-12. 2011-04-11 17:16 Mw 6.6, Mj 7.0 10 kmMagnitude 6.6 – EASTERN HONSHU, JAPAN . Earthquake.usgs.gov. Retrieved on 2011-04-12. 6- 6 dead, several injured, localized power outage and landslides in Iwaki, Fukushima. 2011-04-12 14:07Mj 6.4 15 km 6- 2011-07-10 09:57 Mw 7.0, Mj 7.3 23 km 4 10 cm of tsunami in Sōma and Ōfunato. 2012-12-07 17:18 Mw 7.3 49 km (JMA) 36 km 5- Tsunami under 1 meter. Considered an aftershock by the National Earthquake Information Center in Colorado, USA.Japanese Quake Stirs On-Air Alarm, but No Damage to Nuclear Plants Is Reported , New York Times 2013-10-26 02:10 Mw 7.1 10 km 4 Tsunami 2016-11-22 05:59 Mw 6.9 9 km 5- 2021-02-13 23:07:497.17.335 km (USGS)55 km (JMA) 6+ This earthquake resulted in at least 1 death and left at least 185 injured. 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.2021-03-20 18:09:457.06.954 km (USGS)60 km (JMA) 5+11 people injured.

Possibly related earthquakes The following earthquakes are possibly related to the 2011 Tōhoku earthquake. However, agreement toward the relationships has not been reached among the researchers.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. Japan Time Magnitude Coordinates Depth Intensity (shindo) Comment 2011-03-12 03:59 Mw 6.3, Mj 6.7 8 km2 kmUSGS Earthquake Hazards Program: Preliminary Earthquake Report: NEAR THE WEST COAST OF HONSHU, JAPAN . Neic.usgs.gov. Retrieved on 2011-04-12. 6+ Possibly a triggered earthquake.2011年3月 東北地方太平洋沖地震 | 広報アウトリーチ室 . Outreach.eri.u-tokyo.ac.jp. Retrieved on 2011-04-12.「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. 2011-03-12 04:31 Mj 5.9 1 km 6- Possibly a triggered earthquake. 2011-03-12 05:42 Mj 5.3 2 km 6- Possibly a triggered earthquake. 2011-03-15 22:31 Mw 6.0, Mj 6.4 9 kmUSGS Earthquake Hazards Program: Preliminary Earthquake Report: EASTERN HONSHU, JAPAN . Neic.usgs.gov (2011-03-15). Retrieved on 2011-04-12. 6+ 50 injured. Power outage. Near presumed location of magma chamber of Mount Fuji.Sinistral strike-slip fault.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. Possibly a triggered earthquake.東日本沖巨大地震 . Sk01.ed.shizuoka.ac.jp. Retrieved on 2011-04-12.2021-05-01 10:27:276.847 km 5+Three people were injured by the strong shaking.2022-03-16 23:36:337.37.463.1 km (USGS)57 km (JMA) 6+ A tsunami advisory was issued by the Japan Meteorological Agency for this earthquake. There was 4 dead and 225 injured. An estimated 2.2 million households from 13 prefectures and one metropolitan area were left without power.

References

USGS

Other

External links About triggered earthquakes in the inland area of the Japanese archipelago (Nagoya University)