The Tokyo Metropolitan Government says 9,700 people could die in a huge earthquake hitting directly under the capital.
The government's first estimate in 6 years is based on a worst-case scenario of a magnitude-7.3 quake in the northern part of Tokyo Bay, with a focus closer to the ground than previously assumed.
The government says at about one-third of Tokyo's 23 wards people could experience tremors up to an intensity of 7, the maximum on the Japanese scale, and that 70 percent of the area could experience tremors of 6-plus.
The government says such a quake could collapse or heavily damage nearly 400,000 buildings. It says if the quake hits at around 6 PM on a windy winter day, fires could destroy about 200,000 buildings.
The result would be 9,700 dead -- up 50 percent from the government's estimate 6 years ago.
The government also estimated tsunami damage to Tokyo resulting from a magnitude-8 quake occurring at an underwater trough south of Tokyo.
It says a tsunami up to 2.6 meters high could surge into Tokyo Bay, but would be blocked by seawalls and floodgates. But it says if all the floodgates were damaged by the quake and could not be shut, 16 wards would be partially flooded up to about one meter, destroying or heavily damaging up to 2,500 buildings.