What is the Nankai Trough megaquake, the disaster warned by the 'New Baba Vanga' and how Japan is bracing for it?

Japan’s government has formally approved a new disaster preparedness plan to brace for a catastrophic earthquake expected to strike along the Nankai Trough — a massive fault line off the country’s Pacific coast. The decision was taken during a recent meeting of the Central Disaster Management Council at the Prime Minister’s official residence, according to NHK.

What’s drawing even more public attention is a chilling prophecy by Ryo Tatsuki, a Japanese manga artist often referred to as the “New Baba Vanga.” In her published predictions, Tatsuki warned that a giant seabed crack would open between Japan and the Philippines, unleashing an earthquake followed by tsunami waves “three times taller” than those seen in the devastating 2011 Tohoku disaster.

What Is the Nankai Trough Megaquake?

The Nankai Trough megaquake refers to massive earthquakes that occur along the Nankai megathrust — the fault line marking the boundary between the subducting Philippine Sea Plate and the overriding Amurian Plate (part of the Eurasian Plate) beneath southwestern Japan.


These quakes typically occur every 90–200 years and often strike in pairs. Notable historical examples include the 1854 Ansei-Tokai and Ansei-Nankai earthquakes (which struck one day apart), as well as the 1944 Tonankai and 1946 Nankaido quakes. At least 12 major events have been recorded in the last 1,300 years.

Worst-Case Scenario: 298,000 Deaths, Millions of Buildings Destroyed

According to a government estimate released in March, a worst-case Nankai Trough earthquake could kill up to 298,000 people and destroy 2.35 million buildings.

Japan’s new basic disaster plan — which updates a 2014 version — aims to reduce potential deaths by 80% and cut structural damage by 50% over the next decade. Despite falling short of these goals in the past, the government has opted to retain the targets, citing the importance of setting high standards when lives are at stake.

How Japan is Preparing for the Megaquake

Reinforce Housing: All homes in high-risk zones will be made earthquake-resistant.

Evacuation Shelters: The government will improve shelters, especially in coastal regions prone to tsunamis.

Annual Progress Reviews: About 200 specific targets have been set, and progress will be reviewed yearly.

Support for Local Authorities: The central government will assist local governments in implementing safety measures.