After Myanmar and Thailand, The Country Braces for Megaquake, Tsunamis: 300,000 Lives at Risk | What we Know

Tokyo: Japan is on high alert as the Japanese government on Monday issued a stark warning about a long-anticipated megaquake off its Pacific coast, which could trigger devastating tsunamis, destroy hundreds of buildings, and might claim around 300,000 lives. A newly released report highlights the severity of the threat, reinforcing concerns about Japan’s vulnerability to large-scale seismic events.   

First-Ever Megaquake Advisory Issued

Last year, Japan took the unprecedented step of issuing its first-ever megaquake advisory. Authorities cautioned about a "relatively higher chance" of a magnitude 9 earthquake striking the region after a magnitude 7.1 tremor was recorded at the edge of the Nankai Trough.

Economic Impact Could Reach $1.81 Trillion

According to a report accessed by Reuters, Japan’s economy could suffer losses amounting to $1.81 trillion if such a catastrophic quake occurs. This figure—equivalent to 270.3 trillion yen—accounts for nearly half of the country’s total Gross Domestic Product ( GDP ). The updated estimate surpasses the initial projection of 214.2 trillion yen due to inflationary pressures and revised terrain and ground data, which now indicate an expanded flood impact zone.   

Massive Displacement and Loss of Life Feared

In a worst-case scenario involving a magnitude 9 earthquake, Japan could see up to 1.23 million people displaced—approximately 10% of its total population. The report warns that if such a quake occurs late at night during winter, as many as 298,000 people could perish due to tsunamis and collapsing buildings.

Nankai Trough: A Seismic Time Bomb

Japan, one of the world’s most earthquake-prone nations, has been closely monitoring the Nankai Trough—a 900 km (600-mile) long seabed zone off the country's southwest Pacific coast. The trough, where the Philippine Sea Plate is subducting under the Eurasian Plate, has accumulated immense tectonic strain. Experts estimate an 80% probability of a magnitude 8 to 9 earthquake occurring in this region within the next century.

Memories of the 2011 Disaster Linger

Japan has previously faced the catastrophic consequences of a magnitude 9 earthquake. The 2011 quake triggered a devastating tsunami and led to triple reactor meltdowns at the Fukushima nuclear power plant, resulting in over 15,000 deaths. The latest warnings serve as a grim reminder of the potential devastation that could unfold if another megaquake strikes.

Earthquake in Myanmar, Thailand

The alert by the Japanese government comes in the wake of powerful earthquakes that recently struck Myanmar and Thailand, raising concerns about heightened tectonic activity in the region. A 7.7-magnitude quake, centered over 1,200 kilometers (800 miles) away, claimed more than 1,700 lives in Myanmar and at least 18 in Thailand. In Thailand, most casualties occurred at a construction site near Bangkok’s renowned Chatuchak Market.