Nearly 600,000 people across Japan took part in an annual earthquake drill on Monday on the 85th anniversary of a killer temblor that flattened Tokyo, a Cabinet official said.
Prime Minister Yasuo Fukuda held an emergency Cabinet meeting in response to a mock quake measuring magnitude 8.6 off the coast of Wakayama in western Japan, the official from the Cabinet Office said on condition of anonymity, citing department policy.
The drill centered on the coastal city of Kishiwada and involved Japan's military, police, the coast guard and firefighters. In the exercise, the participants rescued passengers stranded on a ferry at sea.
A magnitude-8.3 quake known as the Great Kanto Earthquake hit Tokyo on September 1, 1923, killing more than 140,000 people.
A team of experts assembled by the government has estimated that if two quakes, both measuring 8.6, hit Japan at the same time, 18,000 people would likely be killed and damage could be as much as 57 trillion yen (US$523 billion), the official said.
Some 15,000 people took part in a separate earthquake drill on Sunday in Tokyo, including rescue teams from South Korea and Taiwan, and the US military, whose amphibious assault ship USS Essex was in the Tokyo Bay area to ferry stranded commuters. In the Tokyo drill, armored vehicles cruised through Ginza, the capital's classy shopping district, while firefighters staged a mock rescue of shoppers in a department store.
Japan is one of the world's most earthquake-prone countries, and experts believe Tokyo has a 90 per cent chance of being hit by a major quake over the next 50 years.
In 1995, a magnitude-7.2 quake in the western port city of Kobe killed 6,400 people.