A big earthquake in Tokyo could create a giant human traffic jam as commuters clog the streets trying to walk home, a government study has revealed.
A powerful earthquake during the daytime could force millions of people to walk home, packed into streets in conditions similar to a crowded commuter train if the tremor were to knock out public transportation, the study said.
About two million commuters would be forced to cram into densely-packed areas for more than three hours, according to the report from the Cabinet Office's Central Disaster Prevention Council, published Wednesday.
Six or more people could be squeezed into an area of one square metre (11 square feet) in Tokyo, the world's largest metropolis.
It could take workers 15 hours to trek 20 kilometres (12 miles) from the financial district of Marunouchi to a home in the town of Wako, north of Tokyo -- three times longer than it normally would, the study said.
Japan, which lies at the crossing of four tectonic plates, endures about 20 percent of the world's powerful earthquakes, frequently jolting Tokyo and other major cities where buildings are made to be tremor-resistant.
A 7.3-magnitude major earthquake in Tokyo would kill 4,700 people, damage 440,000 buildings and leave thousands of others trapped in elevators, according to a study published by the government in 2006.
The last major tremor in Tokyo was the Great Kanto Earthquake of 1923 which left 142,807 people dead or unaccounted for. Japan marks the September 1 anniversary each year with nationwide disaster preparation drills.
