Downfall of Tokyo due to Devastating Compound Disaster
Faculty and Graduate School of Safety Science, Kansai University, 7-1 Hakubai-cho, Takatsuki-shi, Osaka 569-1098, Japan
Compound disasters are defined as double- or triplepunch disasters. As such, they cause more serious cumulative damage than individual disasters occurring independently. The independent occurrence of Tokyo metropolitan inland earthquakes is expected to kill 11,000 and cause ¥112 trillion in damage. An earthquake in Tokyo would also destroy river levees, coastal dikes, and disaster measure facilities such as water gates and locks due to liquefaction. Following such a earthquake, river flooding by the Tone and Arakawa rivers or storm surge overflow around Tokyo bay could easily occur along with strong typhoons. An Edo period (1603-1868) compound disaster involved the 1855 Ansei Edo earthquake and the 1856 Ansei Edo storm surge. With global warming progressively worsening, huge floods and storm surges are increasingly likely to occur independently. The risk that they will occur as part of a compound disaster is also increasing. Catastrophic disasters are characterized by being super-wide in area damage, compound in combining disasters, and prolonged in recovery. With the vast sea-level or low areas in Tokyo, long-term submergence due to inundation will be unavoidable. The most difficult problem, however, will be how to evacuate over 1 million people.
-  H. Hayashi, “Some Research Results of Crisis Management Following Tokyo Metropolitan Near Field Earthquake Disaster,” Report of the 3rd Symposium on Catastrophic Compound Disasters and Their Disaster Reduction Strategy, 2010 (in printing).