Today is the 5th anniversary of the 2011 Great East Japan Earthquake and Tsunami. At 1446 Japan local time on 11 March 2011, a M9.0 earthquake occurred off the northeastern coast of Honshu, Japan, that generated a devasting tsunami. Total damage was estimated at USD $220 billion, making it the most expensive disaster in history. It was the largest magnitude earthquake ever in Japan and is the 4th largest in the world since 1900. In many coastal towns, waves flooded to at least the 3rd or 4th floor of buildings. Over 18000 persons lost their lives – nearly all from the relentless tsunami waves. The Japan Meteorological Agency issued its 1st tsunami warning in three minutes, updated it after 28 minutes, and continued its danger advisories for over 2 days.
500,000 houses were completely or partial destroyed, and about 500,000 people displaced. 98% of the damage was due to the tsunami. 7,600 houses were destroyed by earthquake ground shaking and 19,000 damaged by liquefaction. After the earthquake, there were 345 fires in 12 prefectures. Infrastructure damage included 4,198 parts of roads, 116 bridges, and 29 parts of the railway. The earthquake and tsunami also caused a nuclear disaster in Fukushima with an International Atomic Energy Agency (IAEA) rating of 7 that included equipment failures, explosions.
The tsunami was observed throughout the Pacific, and in Japan, at over 60 Japanese tide stations as well as a dozen ocean bottom pressure gauges, and another dozen GPS wave gauges. The tsunami was first observed along the Sanriku coast about 30 minutes after the earthquake and at the Sendai plain about 30 minutes later. The maximum wave height of 38.9 meters was determined from Japanese field surveys by a team of approximately 300 researchers that documented tsunami impacts along a 2,000 kilometer stretch of Japan’s Pacific coast that inundated 561 km2 of land. On the Sendai Plain, the maximum water level height was 19.5 meters. The tsunami flooded more than 5 kilometers inland from the coast, and as much as 15 km inland at rivers.
The 2011 Great East Japan earthquake generated a great tsunami that went far beyond any of the pre-disaster expectations. This earthquake and tsunami, along with the 2004 Sumatra earthquake and tsunami in the Indian Ocean, has since caused scientists and policy-makers all over the world to reconsider their earthquake and tsunami hazard assumptions and preparedness measures.
For more information of the 2011 Great East Japan Earthquake and Tsunami, click HERE.