The research institute 's findings carry great consequences for the 42 million people who live in the Tokyo metropolitan area . more than 15,700 people live in Tokyo metropolitan area . Institute : Tokyo faces 70 % probability of M-7 quake within four years , 70 % chance within 30 years . Government puts 70 % probability of magnitude-7 quake in region within 30 years . four years quake and tsunami left Forty-two million dead , government says .
more than 15,700 people live in Tokyo metropolitan area . Institute : Tokyo faces 70 % probability of M-7 quake within four years , 70 % chance within 30 years . Government puts 70 % probability of magnitude-7 quake in region within 30 years . four years quake and tsunami left Forty-two million dead , government says .