Forty - two million people live in Tokyo metropolitan area . Institute : Tokyo faces 70 % probability of M-7 earthquake within four years , 98 % chance within 30 years . About 4,500 were listed as missing . Government faces 70 % probability of magnitude-7 quake in region within 30 years . March 11 quake and tsunami left more than 15,700 dead , government says .
Forty - two million people live in Tokyo metropolitan area . Institute : Tokyo faces 70 % probability of M-7 earthquake within four years , 98 % chance within 30 years . Government faces 70 % probability of magnitude-7 quake in region within 30 years . March 11 quake and tsunami left more than 15,700 dead , government says .