Abstract

On 11th March, 2011, a Mw9.0 earthquake occurred in the Japan Trench off the coast of Tohoku in north-east Japan. Ground shaking was felt as far as western Japan and lasted for almost four minutes (220 seconds), generating large, unprecedented tsunamis toppling sea defences and destroying entire settlements and towns along the coastline. This Mw9.0 earthquake is the largest event that has been recorded in Japan since the beginning of instrumental seismology circa 1900. The government of Japan (GoJ, 2011) announced the estimated total direct loss to be around £16.9 trillion (£140 billion), making this the world’s costliest earthquake. Japan is exposed to some of the world’s most extreme natural hazards and is considered to be one of the most prepared countries in terms of earthquake and tsunami. However, not many would have expected an earthquake and tsunami with such magnitude and consequence to one of the most developed countries in the world. Considering the historic significance of the event, Earthquake Engineering Field Investigation Team (EEFIT) under the auspicious of the Institution of Structural Engineers(IStructE) deployed a multidisciplinary team of 9 to conduct a 5-day field mission in the Tohoku region in May this year. Observations and findings from the mission will be presented.