Here's an interesting article, suggesting that when (not if, it seems) Tokyo gets its next big earthquake, you may be best off heading up, rather than anywhere else:
So, what to do?:Should, as government agencies are predicting, a major earthquake occur within 100-150 km of Tokyo Bay in the Tokai area or Ibaraki's Oki region, Hiroshi Takagi, an associate professor of engineering at the Tokyo Institute of Technology, believes the resultant tsunami would be similar to or greater in height than the Tohoku tsunami.
"The southwestward opening of Tokyo Bay makes it particularly vulnerable to tsunami from the Tokai region," said Takagi.
Takagi, who coauthored "Behavior of the 2011 Tohoku Earthquake Tsunami and Resultant Damage in Tokyo Bay," reported that major quake-induced tsunami have struck Tokyo Bay in 1703, 1854, 1923 and 1960 as well as on March 11, 2011. The largest tsunami to hit Tokyo Bay is thought to have been the result of the 1703 Great Genroku Earthquake, which flooded areas of Miura 6-8 meters above sea level in the south, parts of Yokohama at 3-4 meters elevation and, as far north as Funabashi, areas at 2 meters elevation.
I didn't know this about last year's Tohoku earthquake, either:"The only safe way to escape a tsunami," said Tossani, "is up." Our restaurant, in fact, was 11 meters above sea level, or four meters shy of the minimum 15-meter clearance he believes is required to avoid an advancing tidal wave, should it resemble the Tohoku tsunami of 3/11.Although counterintuitive, if a tsunami was to strike Tokyo, you might well be safer on the top floors of a Tokyo skyscraper than anywhere else. Tossani should know: He is an architect, master planner and urban designer who researched the actions of those who survived and perished in Tohoku last year for the newly published "Natural Disaster and Nuclear Crisis in Japan" (Routledge).
How unfortunate."What we discovered in Tohoku was that many of the maps published by the Ministry of Land, Infrastructure and Transportation distributed to local municipalities indicated areas as low risk that were in fact death zones," said Tossani. "Because many of the municipalities had distributed maps that showed only the four-meter zones, many people made a beeline for them, only to be overwhelmed."
Twelve evacuation sites out of 25 designated by the Onagawa government as safety zones were swept away. In Minamisanriku, also in Miyagi Prefecture, 31 of 80 sites were washed away. In total the tsunami swept away more than 100 evacuation sites along the Tohoku coast. "That contributed to the direct loss of thousands of lives," said Tossani.