Simultaneous Nankai Trough Earthquake and Massive Typhoon Could Trigger Mega Tsunami Exceeding 340,000 Fatalities Estimate
In August, the Hyuga-nada Sea off Miyazaki and western Kanagawa Prefecture were hit by tremors measuring just under 6 on the Japanese seismic scale and just under 5 on the Japanese seismic scale, one after another. Although the government's call for "massive earthquake caution" has ended,...... the threat of a Nankai Trough earthquake and a massive typhoon is rising. The death toll will not be contained to the 320,000 people the government expects. A mega tsunami caused by the double disaster will hit the Pacific coast!
A house that collapsed due to the earthquake that occurred off the coast of Miyazaki on August 8th.“It was an intense lateral shake like I had never experienced before. The shop is on the 4th floor, and the building is old. I seriously prepared myself for death, either by being crushed when the building collapsed or by being burned to death in an explosion from the gas in the kitchen.”
Recalling this terrifying experience is Hitoshi Hiyoshi, manager of the izakaya ‘Ichiryūmanbai’ in the bustling district of “Nishitachi” in Miyazaki City.
Strong tremors have been occurring frequently across Japan. The major earthquakes in August are as follows:
・August 8th, off the coast of Miyazaki in Hyuganada: intensity 6 lower, magnitude (M) 7.1.
・August 9th, western Kanagawa Prefecture: intensity 5 lower, M 5.3.
・August 15th, same area: intensity 4, M 4.4.
The Nankai Trough Earthquake Strikes Suddenly
What is eerie is that all of these earthquakes occurred near the epicenter areas predicted by the government for the Nankai Trough Earthquake. Following the earthquake off the coast of Miyazaki, the Japan Meteorological Agency issued, for the first time, a special Nankai Trough Earthquake advisory, warning of a “potential massive earthquake.” With the government estimating a 70-80% chance of the Nankai Trough Earthquake occurring within the next 30 years, this advisory sent a wave of tension across the country, as people wondered, “Has the time finally come?”
Yoshiaki Kawata, a special-appointed professor at Kansai University and an expert on natural disasters, explains:
“The Nankai Trough Earthquake will occur suddenly. With the issuance of this advisory, even those who have been indifferent should now realize that a massive earthquake will happen eventually. It is wrong not to prepare in advance.”
There is a concerning phenomenon. According to the Miyazaki Observatory at Kyoto University’s Disaster Prevention Research Institute, since the earthquake on the 8th, “slow earthquakes,” where the fault off the coast of Miyazaki slowly slips, have been occurring frequently. It is known that similar slow earthquakes were frequent just before the Great East Japan Earthquake in March 2011, which triggered a massive M9 earthquake with a maximum seismic intensity of 7. Although the “Massive Earthquake Warning” was lifted on August 15th, the threat of a Nankai Trough Earthquake has only intensified.
During the same period when slow earthquakes were frequent off the coast of Miyazaki, Japan was hit by another disaster. A very strong Typhoon No. 7 approached, with a central pressure of 950 hPa and a maximum instantaneous wind speed of 60 m/s, causing disruptions like the suspension of the Tokaido Shinkansen. Weather forecaster Koji Murayama explains:
“In recent years, sea surface temperatures near Japan have exceeded the 30-year average from 1991 by 3 to 4 degrees Celsius, reaching around 30 degrees off the Izu Peninsula. One of the conditions for typhoon formation is a sea surface temperature of around 27 degrees Celsius. Previously, powerful typhoons would form near the warm waters of the Philippine Sea, but now it has become normal for them to form near Japan.”
The massive typhoons that are expected to frequently hit Japan are not unrelated to the Nankai Trough Earthquake. It is believed they will intensify the devastating power of the tsunami, which is expected to claim around 230,000 lives. Murayama continues:
“It is said that when the central pressure of a typhoon drops by 1 hectopascal, the sea level rises by 1 cm. Compared to a relatively weak typhoon of 1000 hPa, this time with Typhoon No. 7 (950 hPa), the sea level would rise by 50 cm. It is anticipated that a powerful typhoon would significantly amplify the damage caused by the tsunami.”
In August 2012, in response to the Great East Japan Earthquake, the government’s Central Disaster Management Council expanded the assumed epicenter area for the Nankai Trough Earthquake. In the worst-case scenario, more than 320,000 deaths are projected. However, if the tsunami, which is expected to reach heights of up to 34 meters, coincides with the occurrence of a massive typhoon, the height could increase even further. This could lead to a mega tsunami, with an even greater risk of widespread destruction. Kawata, mentioned earlier, explains:
“The most terrifying disaster in conjunction with an earthquake is a typhoon that brings heavy rain and causes landslides. During the Niigata Chuetsu Earthquake in October 2004, Typhoon No. 23 had just passed through, causing landslides in around 4,000 locations in the mountainous regions.”
The risk of these twin disasters remains until October, when massive typhoons are most likely to occur.
From ‘FRIDAY’, September 6 & 13, 2024 Combined Issue.
PHOTO： Shun Kirishima, Kyodo News
