The Tokyo Metropolitan Disaster Management Council, summarized a report on “Damage estimation for an earthquake directly underneath Tokyo” in May, 2006. Such earthquakes are supposed to imminently occur as M7.3 earthquake together with M6.9 one beneath the northern Tokyo Bay, because an earthquake of magnitude level 6 is more frequently to take place than the M7 one. In addition to the traditional estimation of human damage, it newly includes the number of stranded persons at large terminal stations and locked-in people in elevators as some typical features of disasters in modern cities. The northern Tokyo Bay earthquake produces ground shake of the Japan Meteorological Agency seismic intensity scale 6+ in the eastern wards area owing to bad ground structure. The number of houses collapsed by shock and/or liquefaction as well as those burnt down by fire increases in the ring-shaped zone of wooden houses in the wards area. In case of M6.9 earthquake, human damage amounts to about 2, 800 people dead, 51% of which due to fire, about 75, 000 people injured, 43% of which due to house collapse, 32% due to fall down of furniture etc. The number of refugees amounts to 2.71 million people, while stranded persons to 4.48 million people. About 7, 500 elevators stop to cause locked-in troubles. Tokyo Metropolitan Government revised the earthquake disaster countermeasure plan based on the new damage estimation report in May 2007.