Tsunami Warnings for Japanese Archipelago: Strive to ‘Fear Properly’ Based on Accurate Information

Editorial

15:23 JST, July 31, 2025

The Japanese archipelago could see a massive earthquake anywhere and at any time, and tsunami could follow. It is important to strive to “fear properly” based on accurate information.

A magnitude 8.7 earthquake struck near Russia’s Kamchatka Peninsula, prompting tsunami warnings across a wide swath of coast, from Hokkaido to Wakayama Prefecture. The Kamchatka Peninsula is a seismically active area, with a magnitude 7.4 earthquake having also struck recently, on July 20.

In Russia’s Far East region, near the latest quake’s epicenter, tsunami waves of 3 to 4 meters reportedly submerged buildings, resulting in casualties. In Japan, the earthquake measured 2 on the Japanese seismic intensity scale of 7 in eastern Hokkaido and 1 in the Tohoku region, with some areas along the Pacific coast observing tsunami over 1 meter in height.

When a massive earthquake occurs, tsunami can reach areas far from the quake’s epicenter. Even if an earthquake is not close to us, we should not let our guard down.

In Chile’s 1960 earthquake, tsunami crossed the Pacific Ocean and reached Japan nearly a day after the quake occurred. The waves reached over 5 meters in height along the Sanriku coast and resulted in numerous deaths nationwide.

Similarly, in the latest quake, tsunami continued to arrive over many hours after the shaking, prompting many local governments to issue evacuation directives to residents. Train services were suspended, mainly in coastal areas, and some beaches busy with summer vacationers were closed for swimming.

Even if there was no damage as a result, it is safe to say that this was the necessary approach. It is frightening that when people are excessively optimistic, they think, “Everything will be fine anyway.” When a warning is issued, it is important to take action to safeguard your life, such as evacuating to higher ground immediately.

Businesses that run tourist and other facilities should review again whether they were able to effectively warn people about the tsunami and guide people to evacuate, and they should apply the lessons learned to future situations. Among other steps, the central and local governments must continue to promote the construction of tsunami towers where residents can evacuate.

Since tsunami waves arrive intermittently, the first wave is not necessarily the largest. This means it often takes time for warnings to be lifted.

On the day of the quake, the maximum temperature exceeded 40 C in some areas. When evacuating and waiting outdoors in extreme heat, people must watch out for heatstroke.

There are concerns that earthquakes could occur in the Japan Trench and Chishima Trench, as well as in the Nankai Trough. Unlike the recent earthquake, a temblor in these areas could trigger a massive tsunami that would leave little time to evacuate before it arrives.

It is important to always check evacuation routes and inspect emergency supplies such as water and food on a regular basis, and to prepare oneself to respond calmly in emergencies.

(From The Yomiuri Shimbun, July 31, 2025)