Japan megaquake could raise 33-foot tsunami, kill 320,000, evict 9.5 million

In the video, Gao Mengtan from the Institute of Geophysics at the China Earthquake Administration explained that a partial rupture within the Nankai Trough, the origin of the recent earthquake, could trigger a magnitude 8.5 quake. Meanwhile, a complete rupture could lead to a magnitude 9.1 earthquake.

The Nankai Trough is an area off the coast of Japan on the Pacific Ocean, where the Pacific Plate and the Philippine Sea Plate form a fault line.

A full rupture earthquake could potentially generate a tsunami exceeding 10 meters (33 feet) in height, as reported by the South China Morning Post. Gao and his team projected that such an event would lead to the destruction of 2.38 million buildings, claiming the lives of approximately 320,000 people and displacing an additional 9.5 million.

Kyushu is a hub for Japan’s semiconductor industry. It is home to more than 200 manufacturers, and roughly half of the country’s semiconductor output comes from that area.

“Cities near the Nankai Trough, especially in the Chugoku and Kansai clusters, are key economic centres, accounting for 70 per cent of Japan’s manufacturing,” Gao explained in his video.

“An earthquake in this region would not only affect Japan’s manufacturing sector but also affect the global supply chain, with potential economic losses reaching 220 trillion yen [US$1.5 trillion], twice Japan’s annual budget.”

Is the Nankai Trough region overdue a major earthquake?

It’s worth noting that the August 8 earthquake that hit Kyushu island did not lead to widespread devastation. However, it did lead the Japan Meteorological Agency to warn that there is an increased probability of a significant earthquake taking place near the trough over the next few days.

According to Gao, the Nankai Trough has generated a major earthquake roughly once every 117 years. The last significant earthquake in the region occurred in 1946, and it generated a 6.9-meter tsunami. This, Gao said, represents the high risk in the region of another major catastrophic event.

Japan is increasingly using technology to mitigate the effects of such disasters. In 2021, for example, Riken and Fujitsu announced that they had developed a powerful predictive AI tool that enables near real-time predictions of flooding caused by tsunamis.