Japan's Megaquake Warning: Up to 3 Lakh Deaths Feared – What Sri Lanka Needs to Know

A potential "megaquake" in Japan could result in nearly 298,000 deaths and economic damage exceeding $2 trillion, according to new estimates released by the Japanese government. This alarming forecast follows a magnitude 7.1 earthquake in southern Japan in 2024, which injured 14 people. Authorities have also warned that such an event could lead to the evacuation of 1.23 million people—nearly 10% of Japan’s population.

Understanding the Nankai Trough Threat

Japan issued its first-ever megaquake advisory in August 2024, specifically for the Nankai Trough, a 900-kilometer-long undersea fault stretching from Shizuoka to Kyushu. This area has been historically prone to massive earthquakes, with past records showing they occur every 100-200 years. The last major quake along this fault struck in 1946.

Seismologists warn that the Nankai Trough has a 70-80% probability of producing a magnitude 8-9 earthquake within the next 30 years. A rupture here could trigger devastating tsunamis reaching up to 34 meters high within minutes, posing extreme risks to Japan’s coastal cities such as Shizuoka, Kochi, and Wakayama.

Why This Matters for Sri Lanka

Sri Lanka, like Japan, is vulnerable to undersea earthquakes and tsunamis. The 2004 Indian Ocean tsunami—triggered by a 9.1 magnitude earthquake near Sumatra—killed over 35,000 Sri Lankans and displaced over half a million.

If a megaquake strikes the Nankai Trough, its impact could be felt across the Pacific and Indian Oceans. While Sri Lanka is geographically distant, the possibility of indirect effects—such as tsunami risks, economic disruptions, or global supply chain impacts—cannot be ignored.

Japan’s Preparedness & What Sri Lanka Can Learn

Japan has significantly strengthened its earthquake early-warning systems and disaster response following the 2011 Tōhoku earthquake and tsunami, which killed 18,000 people and caused the Fukushima nuclear disaster. Their strict building regulations, tsunami defenses, and evacuation plans are crucial in minimizing casualties.

For Sri Lanka, investing in early-warning systems, tsunami preparedness, and earthquake-resistant infrastructure is essential to prevent future disasters. Experts emphasize that “The time for preparedness is now—not when the ground begins to shake.”

While Japan faces a growing threat from the Nankai Trough, the risk of undersea quakes and tsunamis should serve as a reminder for Sri Lanka to remain vigilant and prepared. Strengthening disaster management, improving coastal defenses, and educating communities could make a crucial difference in minimizing loss of life and property in the event of a future seismic catastrophe.