Photo/Illutration Train delays and service cancellations are displayed following the release of the Nankai Trough Earthquake Extra Information at JR Tokyo Station on Aug. 9, 2024. (Asahi Shimbun file photo)

The Cabinet Office has revised its guidelines on how companies and local governments should respond to emergency information about a possible megathrust earthquake in the Nankai Trough off the Pacific coast.

It clarified that railway operations and businesses in general are not required, in principle, to suspend their operations. In fact, it said it is preferable to continue holding events when an advisory is issued.

There are a range of alerts, depending on the scale of the anticipated emergency.

One advisory is for an earthquake with a magnitude ranging from 7.0 to under 8.0 occurring when one tectonic plate slides beneath another in a specific area, or focal region, of the Nankai Trough.

The government has said there is an 80 percent chance of a Nankai Trough megaquake hitting within 30 years. In a worst-case scenario, it projected 298,000 fatalities from such an event.

Another alert is for when a magnitude 8-class earthquake occurs in the same area.

The advisory was issued for the first time last year following an Aug. 8 earthquake off the coast of Miyazaki Prefecture with a maximum seismic intensity of lower 6 on the Japanese scale of 7. 

The previous guidelines hardly referred to the Nankai Trough Earthquake Extra Information advisory, triggering confusion over whether to suspend events and railway services.

Under the revisions issued on Aug. 7, local governments and businesses are encouraged to continue their socioeconomic activities when an advisory is issued, with the caveat that officials should “make their own decisions” based on safety considerations.

SAFETY FIRST

Municipalities and businesses try to balance earthquake and tsunami preparedness with socioeconomic activities.

Shirahama in Wakayama Prefecture, where tsunami waves of one meter are predicted to arrive within as little as three minutes following a Nankai Trough megaquake, closed four beaches last year for six days from Aug. 9, the day after the advisory was issued.

At the time, the national guidelines did not specify whether tourist facilities should continue operations. In the event, Mayor Yasuhiro Oe decided to close the beaches, saying, “The safety of tourists comes first.”

Hotels and inns near the beaches were hit with a rush of reservation cancellations, partly because West Japan Railway Co. (JR West) suspended express train services south of Wakayama Station.

Shirahama Onsen Ryokan Kyodo Kumiai, a local hotel cooperative, said that about 5,800 bookings were canceled between Aug. 9 and Aug. 18, resulting in estimated losses of 510 million yen ($3.5 million).

Even though the new guidelines urge local governments and businesses to continue as normal, the town intends to close the beaches when the next advisory is issued.

In Nichinan, Miyazaki Prefecture, where seismic activity with an intensity of lower 6 was recorded during a magnitude-7.1 earthquake off the Hyuganada coast, an official acknowledged that city authorities did not make sufficient efforts when the advisory was issued last year.

“Our explanation was insufficient. So, many residents seemed to have interpreted the advisory as a forecast that a major earthquake would occur within a week,” the official said.

To address the matter, city officials upgraded the crisis management room to crisis management section this past April. They also established a new system in the section to stay in contact with residents in an emergency.

This led to greater disaster preparedness awareness, the officials said.

Mayumi Sakamoto, a professor at the University of Hyogo who specializes in disaster information, noted that the Nankai Trough Earthquake Extra Information advisory is intended to prod people to be better prepared, not to predict exactly when an earthquake will occur.

When it was released last year, it was viewed by many people as a concrete forecast, resulting in excessive and unnecessary panic.

Sakamoto commended the government for making the guidelines more practical and urged people to use the information to enhance their preparedness at home, at work and while traveling.

(This article was compiled from reports by Shoko Rikimaru, Kazuhide Setoguchi, Yasukazu Akada and Ryo Sasaki.)

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