Apanel of the Cabinet Office's Central Disaster Prevention Council on March 18 predicted that if a megaquake of magnitude-9.1 occurs in the Nankai Trough off the Pacific coasts, the quake and its ensuing tsunami will cause economic damage amounting to some ¥220 trillion, more than 40 percent of Japan's gross domestic product.

The central and local governments should promptly work out programs aimed at reducing the predicted damage and accelerating postdisaster reconstruction. The panel did not mention damage estimates for nuclear power plants for technical reasons.

An August 2012 estimate showed that a megaquake of magnitude-9 in the Nankai Trough, a 900-km subduction zone off the Pacific coasts stretching from Shizuoka Prefecture to Shikoku, could kill up to 323,000 people in 30 prefectures including Tokyo, with about 70 percent of the deaths tsunami-related.