• Yomiuri Editorial
  • Earthquakes in cold regions

Prepare against huge tsunami hitting late at night in winter

If an earthquake occurs in the winter in the colder regions of northern Japan, affected residents face the risk of freezing to death even if they escape tsunami. The key to minimizing damage is to have measures against the cold in place at evacuation facilities.

In preparation for a massive earthquake with its epicenter anywhere in the area from off Iwate Prefecture to Hokkaido in the Japan Trench or Chishima Trench in the Pacific Ocean, the government has designated 272 municipalities in eight prefectures as areas where countermeasures should be strengthened. Of these, 108 municipalities have been designated as areas where precautions against flooding from tsunami are especially required.

Last year, the government announced its estimate that up to 199,000 people could die if an about magnitude-9 earthquake occurred “late at night in winter,” when evacuation is slowed due to snow accumulation and other factors. The government said the tsunami height is estimated to reach as high as 30 meters in some areas.

Each of the designated municipalities will formulate its own disaster management plans. Unlike a Nankai Trough earthquake and an epicentral earthquake directly under the Tokyo metropolitan area, most of the areas hit by an earthquake occurring near the Japan Trench or Chishima Trench are expected to be experiencing severe cold weather during the winter. Earthquake countermeasures tailored to cold regions are essential.

Tsunami evacuation towers have been constructed to allow residents to climb to elevated floors to take shelter in areas where tsunami are expected to hit. However, the tops of these towers are exposed to open air, and there is not enough cold weather gear available at some towers.

Roofs and walls should be installed to shut out the wind and snow, with the possibility of spending the night in the towers in mind. Preparing such items as tents would also be a good idea. Blankets and heat packs should also be stocked.

It is also important to take measures against the cold at evacuation centers. In addition to heating oil or wood stoves, emergency food that can be eaten warm without a fire should be prepared so that people can stay warm even if the electricity goes out.

In the city of Miyako, Iwate Prefecture, where a major tsunami is feared, residents held an evacuation drill before dawn in March. They used flashlights to light their way to higher ground. Everyone should raise their evacuation awareness so that residents can escape swiftly, even late at night in winter.

Tsunami inundation areas extend beyond the boundaries of municipalities. A system to enable wide-area cooperation among neighboring municipalities as well as the flexible provision of supplies and dispatch of support staff must be developed.

Last month, Typhoon No. 15 caused a large-scale suspension of the water supply in Shizuoka Prefecture, but it took two days before the prefectural government requested the Self-Defense Forces to dispatch a disaster relief mission. Local governments have to coordinate with the SDF and other related agencies in advance so that assistance can be received promptly in the event of an earthquake.

The government claims that the number of expected fatalities can be reduced by 80% if the central and local governments, businesses and residents promote tsunami countermeasures in advance. Earthquakes can occur at any time. Countermeasures must be prepared now.

(From The Yomiuri Shimbun, Oct. 9, 2022)