List of foreshocks and aftershocks of the 2011 Tōhoku earthquake
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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)[1] | Comment |
|---|---|---|---|---|---|
| 2011-03-09 11:45 | Mw 7.3, Mj 7.3[2] | 38.424°N 142.836°E | 32 km[USGS 1] | 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 | 38.171°N 143.043°E | 9 km | 4 | Caused an 11 cm tsunami.[5] |
Main shock
Aftershocks
| Japan Time | Magnitude | Coordinates | Depth | Intensity (shindo)[1] | Comment |
|---|---|---|---|---|---|
| 2011-03-11 15:08 | Mj 7.4[1] | 39.82°N 139.025°E | 32 km[1] | 5- | |
| 2011-03-11 15:15 | Mw 7.9, Mj 7.6[1] | 36.27°N 141.14°E | 43 km[USGS 3] | 6+ | |
| 2011-03-11 15:25 | Mw 7.7, Mj 7.5[1] | 38.05°N 144.59°E | 19 km[USGS 4] | 4 | |
| 2011-04-07 23:32 | Mw 7.1, Mj 7.2[1] | 38.253°N 141.640°E | 42 km[USGS 5] | 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] | 37.007°N 140.477°E | 10 km[USGS 6] | 6- | 6 dead, several injured, localized power outage and landslides in Iwaki, Fukushima.[10] |
| 2011-04-12 14:07 | Mj 6.4[1] | 37.052°N 140.643°E | 15 km[1] | 6- | |
| 2011-07-10 09:57 | Mw 7.0, Mj 7.3[1] | 38.040°N 143.287°E | 23 km[USGS 7] | 4 | 10 cm of tsunami in Sōma and Ōfunato.[11] |
| 2012-12-07 17:18 | Mw 7.3[1] | 37.8°N 144.2°E | 49 km (JMA)[1] 36 km [USGS 8] |
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 | 37.170°N 144.665°E | 10 km [USGS 9] | 4 | Tsunami[13] |
| 2016-11-22 05:59 | Mw 6.9 | 37.393°N 141.387°E | 9 km | 5- | |
| 2021-02-13 23:07:49 | Mw7.1 MJMA7.3 |
37.686°N 141.992°E | 35 km (USGS) 55 km (JMA) |
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 | Mw7.0 MJMA6.9 |
38.475°N 141.607°E | 54 km (USGS) 60 km (JMA) |
5+ | 11 people injured.[16] |
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.[17]
| Japan Time | Magnitude | Coordinates | Depth | Intensity (shindo)[1] | Comment |
|---|---|---|---|---|---|
| 2011-03-12 03:59 | Mw 6.3, Mj 6.7[1] | 37.02°N 138.36°E | 8 km[1] 2 km[USGS 10] |
6+ | Possibly a triggered earthquake.[18][19] |
| 2011-03-12 04:31 | Mj 5.9[1] | 36.948°N 138.572°E | 1 km[1] | 6- | Possibly a triggered earthquake.[19] |
| 2011-03-12 05:42 | Mj 5.3[1] | 36.972°N 138.59°E | 2 km[1] | 6- | Possibly a triggered earthquake.[19] |
| 2011-03-15 22:31 | Mw 6.0, Mj 6.4[2] | 35.29°N 138.54°E | 9 km[USGS 11] | 6+ | 50 injured. Power outage.[20] Near presumed location of magma chamber of Mount Fuji. Sinistral strike-slip fault.[21] Possibly a triggered earthquake.[22] |
| 2021-05-01 10:27:27[23] | Mw6.8 | 38.230°N 141.665°E | 47 km | 5+ | Three people were injured by the strong shaking.[24] |
| 2022-03-16 23:36:33 | Mw7.3 MJMA7.4 |
37.702°N 141.587°E | 63.1 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.[25][26][27] An estimated 2.2 million households from 13 prefectures and one metropolitan area were left without power.[28] |