Megathrust Earthquake Attention: Review Disaster Preparations Carefully and Calmly

Editorial

15:00 JST, August 10, 2024

The first special advisory regarding a potential Nankai Trough earthquake, which is feared may occur in the near future, has been released. First of all, it is important to calmly check daily preparedness, and for the time being, to strengthen vigilance regarding earthquakes.

A magnitude-7.1 earthquake occurred Thursday off the coast of Miyazaki Prefecture, with its epicenter within the presumed focal region of the Nankai Trough earthquake. A maximum intensity of lower 6 on the Japanese seismic scale of 7 was observed in the prefecture, and a number of people were injured. Tsunami were also confirmed in the Kyushu and Shikoku regions.

In response, the Japan Meteorological Agency convened an evaluation and review panel of experts, and issued an advisory called Nankai Trough Earthquake Extra Information, selecting the phrase “Megathrust Earthquake Attention” for the current incident. In short, it urged residents to be cautious against a possible Nankai Trough earthquake. This was a response in accordance with predetermined procedures.

Local governments have set up disaster response headquarters, and those in coastal areas at high risk of tsunami have decided to open evacuation centers and close designated swimming beaches. Central Japan Railway Co. has been operating its Tokaido Shinkansen line at slower speeds on sections of its service area.

Local governments and businesses should consider the risks they face and take appropriate measures.

Up to now, extra information such as Megathrust Earthquake Attention has not been widely known. Many people must have been surprised by the first announcement since the operation of the system of extra information on a possible Nankai Trough earthquake started in 2019.

The probability of the occurrence of a Nankai Trough earthquake is estimated to be 70% to 80% within 30 years. If this is used as the guideline, the probability of the Nankai Trough earthquake has only slightly increased for now. The danger of a mega earthquake can be said to not be imminent and there is no need to be overly fearful.

In addition to the present case, extra information may also be released in the future. It is likely there will be many cases in which a mega earthquake does not actually occur. At home and at work, people are urged to think carefully about how to perceive and deal with such information, which comes with uncertain elements.

For the next week or so, residents are urged to bolster their earthquake preparedness. They should start with what they can do, such as confirming means of communication with family members and evacuation routes, as well as checking that enough emergency food supplies are prepared.

It is important to lead one’s daily life with the risk of earthquakes in mind. For the time being, attention should be paid to information provided by the JMA and local governments.

Many people are probably planning to return to their hometowns or go on trips during summer vacations. If they put plans in place for what to do in the event of an emergency, there would be no need to cancel plans in haste.

If further earthquakes do not occur this time, life will return to normal. But the risk of a Nankai Trough earthquake will not disappear. Regardless of whether or not there is any extra information, it is important to be prepared for earthquakes on a routine basis.

(From The Yomiuri Shimbun, Aug. 10, 2024)