Lessons on vulnerability from the 2011 Tohoku earthquake for Indonesia and the United States

The 2011 Tohoku earthquake and tsunami shocked people relevant for tsunami disaster risk reduction all over the world because such people thought Tohoku has often attacked by tsunamis and has declared one of the most wellprepared areas for tsunami in the world. Each author has separately promoted tsunami education to community in Indonesia for 7 years after the 2004 Indian Ocean tsunami and California US for 19 years after the1992 M7.2 Cape Mendocino earthquake. In order to learn the lesson from the 2011 Tohoku earthquake and tsunami and feedback to Indonesia, US and International society, we examined some of the factors that contributed to impacts in Tohoku based on field reconnaissance and reports from other organizations. The biggest factors exacerbating losses were the underestimation M8 of the real tsunami size M9 in design of prevention structures and evacuation planning coupled with a perception of individuals that they were not at risk. Approximately 86 % of the tsunami victims were in areas outside the mapped tsunami hazard zone in Unosumai town, Iwate. At least 100 chosen tsunami evacuation buildings were either overtopped or structurally toppled by the tsunami. More than 200 people died in the first story gymnasium of elementary school beside the river and canal in areas outside the mapped tsunami hazard zone in Higashi-Matsushima city Miyagi. Around 80 students sacrificed in Okawa Elementary school in Ishinomaki city Miyagi. Additional factors affecting vulnerability included people who were in safe areas at the time of the earthquake, returning to hazard zones after feeling the earthquake to rescue relatives or possessions, and relying on cars for evacuation. Factors that enhanced resilience include the good performance of most structures to earthquake ground shaking and the performance of the tsunami early warning system in stopping trains and shutting down other critical systems. Although power was out in most of the affected region, some cell phones and automobile car radios worked in many areas and were able to provide some warning guidance. Individuals who were able to improvise and make changes in their evacuation plans and routes may have been more likely to survive. As for US, it has triggered a re-examination of how slip and secondary fault rupture may affect the size of the tsunami and engendered debate about how to treat uncertainty in model results while it has not changed the maximum magnitude estimate for an earthquake on the Cascadia subduction zone, it has triggered a re-examination of how slip and secondary fault rupture may affect the size of the tsunami and engendered debate about how to treat uncertainty in model results. It has also raised the priority of FEMA's catastrophic response planning efforts for a great Cascadia earthquake and has invigorated states and local coastal jurisdiction's planning, education, and outreach efforts. Indonesia has been on the way to prepare for tsunami from the Tohoku model after the 2004 Indian Ocean tsunami. I stopped the plan make signboards of numerical tsunami height in Padang Indonesia because such signboards were not effective in Tohoku in this time. We introduce new plans in this presentation.