The MJMA  7.3 or Mw  7.1 earthquake occurred on a Saturday night at 23:07 JST (14:07 UTC) on 13 February at a focal depth of 44.0 kilometers (27.3 mi).

Because of its proximity to the Fukushima Daiichi Nuclear Power Plant, the event provoked concerns of radiation leaks but was dismissed soon after.

The 11 March 2011 Tōhoku earthquake struck off the coast of eastern Japan, with an epicenter north of Sendai, and a hypocenter depth of 29 km.

This subduction zone is capable of producing megathrust earthquakes with magnitudes greater than 8.5, evident in the historical records.

[22] The Japan Meteorological Agency (JMA) observed a maximum intensity of Shindo 5 Lower,[23] or VII (Very strong) according to the US Geological Survey.

However, the Earth Science and Disaster Prevention Research Institute suggested the earthquake may have also caused Shindo 7 shaking at Yamamoto, Miyagi.

[4] This event which occurred near the deeper portion of the subduction interface generated short-period seismic energy which caused severe shaking at the coast.

Class III LPGM results in people finding it hard to stand, fixtures on casters will move about and unsecured furniture may fall over, and partition walls will crack.

Class II LPGM will result in people finding it difficult to walk without holding onto something stable, fixtures on casters will move slightly and objects on shelves may fall.

[33] Nine days after the 10th anniversary of the March 2011 tragedy, a strong 7.0 Mw  or 6.9 MJMA  earthquake struck 80 km north of the epicenter of the February 2021 event.

[76] Seven minutes after the earthquake, the Japan Meteorological Agency projected "slight sea level fluctuation" to occur along the Tōhoku and Kanto coasts.

Other prefectures including Ibaraki, Tochigi, Gunma, Saitama, Chiba, and Kanagawa also reported one or more residents with profound or minor injury.

[88][10] The most severely affected city was Sōma, located some 40 kilometers (25 mi) north of the Fukushima Daiichi Nuclear Power Plant.

[92] At least 311 schools in Fukushima and Miyagi prefectures sustained damage such as cracked walls and floors, broken windows as well as burst water pipes.

[10] Footage and images circulating online suggest that minor damage including broken glass and collapsing facades were caused by the shaking.

[99] According to the Tokyo Electric Power Company (TEPCO), no abnormalities or changes in radiation levels were detected immediately after the earthquake.

Approximately 20 minutes after the shock, a nuclear alert order was issued and both the water treatment and transfer facilities were shut down.

Subsequent inspections the next day also showed no unusual changes to radiation level and the nuclear alert order was rescinded at 2:00 pm on 14 February.

[100] About a week after the earthquake, TEPCO stated that water levels in reactor Units 1 and 3 which were crippled by the 2011 nuclear meltdown had dropped by several tens of centimeters, and has continued to fall each day.

[103] This additional damage may cause further implications in the decommissioning process of the nuclear power plant which is expected within several decades.

The East Japan Railway Company suspended their Tōhoku–Hokkaidō, Akita, and Yamagata Shinkansen services after an inspection revealed damage to various pieces of equipment.

The railway company had mentioned that operations between Nasushiobara and Morioka stations would be suspended for around 10 days to allow for repair works.

[109] JR Bus Tōhoku added more than 20 service routes connecting Fukushima and Sendai stations to the nation's capital, Tokyo.

[93] On the Jōban Expressway, landslides buried parts of the roadway, and embankments along it collapsed; however, no vehicles were trapped inside the debris.

[113] As a result of the temporary suspension of the Tōhoku-Hokkaido Shinkansen, some students from six prefectures in the Tohoku region were unable to take entrance exams administered by some private universities at the designated venues.

[116] The Japan Professional Basketball League which scheduled to host a match between the Sendai 89ers and Gunma Crane Thunders at the Xebio Arena Sendai, and the Fukushima Firebonds and Ehime Orange Vikings at the Fukushima City National Athletic Meet Memorial Gymnasium on February 14 were suspended due to damage found at the hosting venues.

In addition, on the morning of the 14th, a ministerial meeting was held at the Prime Minister's Office to confirm the policy of making every effort for disaster emergency measures.

According to Prime Minister Yoshihide Suga, the affected local governments were closely cooperating and would be on constant vigilance about the secondary disasters such as aftershocks and landslides.

[124] Japanese Prime Minister Yoshihide Suga was informed of the damage and casualties and later confirmed that there were no deaths in the aftermath of the earthquake.

[13] The Fire and Disaster Management Agency headquarters in Iwate Prefecture experienced shaking intensities of Shindo 5 Lower.