Oil storage tanks in industrial parks were heavily damaged by large scale tsunami, and large-scale oil spills occurred, which led to fire in entire city area, after Great East Japan earthquake on March 11, 2011. Much more larger scale disasters of damages and hazardous materials releases will be estimated in Tokyo Bay, Ise Bay or Osaka Bay if Tokai-Tonankai-Nankai earthquake simultaneously occurs. It is very urgent to perform risk assessment of damages and hazardous materials releases caused by large scale earthquake and tsunami, and take countermeasures to decrease such disasters.This research initiative purposes to perform risk assessment of damages and hazardous materials releases caused by large scale earthquake and tsunami, propose countermeasures to decrease such disasters, and finally make concrete guidelines for them.