Earthquake-prone Tokyo has been braced for the “Big One” for decades and when a huge tremor set buildings swaying wildly on March 11, many residents of the Japanese capital thought it had finally arrived.

It had not. Although the magnitude 9 quake was the strongest in Japan’s recorded history, its epicentre was hundreds of kilometres away in the seas off the north-eastern coast. And while the quake triggered a tsunami that scourged coastal communities, damage in Tokyo and its surrounding areas was slight.

Yet the unfolding disaster in the north-east and a parallel crisis at a quake-crippled nuclear power plant offer the starkest of reminders of the need for the capital to do more to ensure it is prepared for any similar seismic assault.

The human and economic cost of a Tokyo earthquake could well exceed the ferocious toll taken by this month’s earthquake and tsunami, which is feared to have killed more than 22,000 people, with about 270,000 still in refuge centres on Tuesday. [ FT.COM ]