March 11, 2011 Earthquake: Honshu, Japan

Felt Reports

At least 15,550 people killed, 5,344 missing, 5,314 injured, 130,927 displaced and at least 332,395 buildings, 2,126 roads, 56 bridges and 26 railways destroyed or damaged by the earthquake and tsunami along the entire east coast of Honshu from Chiba to Aomori. The majority of casualties and damage occurred in Iwate, Miyagi and Fukushima from a Pacific-wide tsunami with a maximum runup height of 37.88 m at Miyako. The total economic loss in Japan was estimated at 309 billion US dollars. Electricity, gas and water supplies, telecommunications and railway service disrupted and several reactors severely damaged at a nuclear power plant near Okuma. Several fires occurred in Chiba and Miyagi. At least 1,800 houses destroyed when a dam failed in Fukushima. Maximum acceleration of 2.93 g recorded at Tsukidate. Horizontal displacement and subsidence observed. Landslides occurred in Miyagi. Liquefaction observed at Chiba, Odaiba, Tokyo and Urayasu.

Tectonic Summary

The 03/11/2011 earthquake near the east coast of Honshu, Japan, occurred as a result of thrust faulting on or near the subduction zone interface plate boundary between the Pacific and North America plates. At the latitude of this earthquake, the Pacific plate moves approximately westwards with respect to the North America plate at a velocity of 83 mm/yr. The Pacific plate thrusts underneath Japan at the Japan Trench, and dips to the west beneath Eurasia. The location, depth, and focal mechanism of the March 11 earthquake are consistent with the event having occurred as thrust faulting associated with subduction along this plate boundary. Note that some authors divide this region into several microplates that together define the relative motions between the larger Pacific, North America and Eurasia plates; these include the Okhotsk and Amur microplates that are respectively part of North America and Eurasia.

The March 11 earthquake was preceded by a series of large foreshocks over the previous two days, beginning on March 9th with an M 7.2 event approximately 40 km from the March 11 earthquake, and continuing with a further 3 earthquakes greater than M 6 on the same day.

The Japan Trench subduction zone has hosted 9 events of magnitude 7 or greater since 1973. The largest of these was an M 7.8 earthquake approximately 260 km to the north of the March 11 event, in December 1994, which caused 3 fatalities and almost 700 injuries. In June of 1978, an M 7.7 earthquake 35 km to the southwest caused 22 fatalities and over 400 injuries.

(above reference #1053)

15,901 deaths and 2,519 missing, 6,167 injured according to Police Measures and Damages Caused by the 2011 Tohoku Pacific Coast Earthquake, as of Mar 09, 2026, National Police Agency of Japan. (ref #9608) (Injuries from Mar 10, 2021 report).

According to the Jiji Press's report as of April 19th, the National Policy Agency issued the breakout of the death (13,135 confirmed by autopsy) separated by age, in Iwate, Miyagi and Fukushima Prefectures, the most affected areas by the Great East Japan Earthquake. The report shows that death of the aged 60 or elder consists of more than 65.2 percent of total death toll, while number of children and youth under 19 consist 6.5 percent. It also reported 5,971 are male, and 7,036 are female. 2,143 (92.4 percent) were drowned to death, and, 578 were crushed to death, 148 were burnt to death. 83.2 percent of the bodies were identified until now. (reference #9445)

Economic losses caused by the magnitude-9.0 earthquake and the resulting tsunami in Japan came to $210 billion, making it the costliest natural catastrophe of all time. (reference #9677)

2011 March 11 05:46:23.15 UTC, 38.285 N 142.546 E, depth 20 km, 9.09 Mw (reference #10476, v10)

2011 March 11 05:46:24.12 UTC, 38.297 N 142.373 E, depth 29 km, 9.1 Mw (reference #13456, access date 2023)