A new study based on lessons learned from last year’s Great East Japan Earthquake indicates that if another major earthquake strikes Japan it could be one of the most fatal earthquakes in history.

Massive tsunamis, collapsing buildings and exploding gas lines would account for most of the damage. Previously, official estimates of a powerful tremor in the Nankai Trough, an undersea trench that runs parallel to the coast of southern Japan, suggested that 24 700 people would be killed. After the March 11 earthquake in 2011, Japan’s Central Disaster Prevention Council examined the data and saw that things were a lot worse than they imagined.

Of course this is a worse case scenario, but the possibility is terrifying. The estimate assumes a tremor with a magnitude of 9 triggering tsunami more than 110 feet high striking coastal towns in Kochi Prefecture. Waves as high as 65 feet would hit eight other prefectures up and down the coast.

Death and destruction would reign as 400 square miles of low-lying land would be flooded as 2,38 million buildings are destroyed, either by the tsunami or fires triggered by gas stoves or heating appliances. Another 623 000 would are estimated to be injured in the disaster.