Disaster-prone areas blind to emergency alerts, Japan quake reveals

Parts of Korea's tsunami-prone east coast could be in an emergency alert blind spot, even as the frequency of natural disasters in the region continues to rise.

Islets of Dokdo seen from the ocean on Oct. 19, 2023. [YONHAP]

Parts of Korea's tsunami-prone east coast could be in an emergency alert blind spot, even as the frequency of natural disasters in the region continues to rise.

Last week, most residents along Korea's east coast received an alert that warned of possible tsunamis in the area — about an hour after a powerful earthquake struck the west coast of Japan. But some people say they didn't get the message — or any caution at all.

According to the Ministry of the Interior and Safety, it sent its first warning text about possible tsunamis to those living along Korea's east coast at 5:11 p.m. on Jan. 1, about an hour after the quake hit the Noto Peninsula of Japan's Ishikawa Prefecture, at 4:10 p.m. That was also about 48 minutes after the Korea Meteorological Administration (KMA) issued a notice on potential tsunamis in the area, at 4:23 p.m. the same day.

An individual working on Dokdo when the earthquake occurred told the JoongAng Ilbo that they did not receive those warnings at those times.

"Others who worked on the islets of Dokdo would have told me if they received such warnings, but none of them did," the individual said. "It seems like there was a network error due to harsh weather conditions."

As earthquakes continue to occur in Japan, issues with Korea's emergency alert system suggest that regions near the East Sea could be insufficiently prepared.

The Japan Meteorological Agency included Dokdo as one of the regions issued with tsunami warnings on Jan. 1, marked in yellow. [JAPAN METEOROLOGICAL AGENCY]

Dokdo is one of the areas prone to the aftermath of Japanese earthquakes. Although Dokdo is capable of receiving emergency disaster messages, residents say that the network becomes frequently unstable in harsh weather.

Urgent news is sometimes relayed by those living on Ulleung Island or the mainland. And it's possible that some residents failed to receive warning texts sent out by the Safety Ministry and local governments last Monday due to poor weather conditions such as heavy winds.

The KMA also failed to provide information on tsunamis for Ulleung Island and Dokdo last week — even as the Japan Meteorological Agency declared Dokdo as an at-risk area. The Korean weather agency announced the anticipated arrival of tsunamis and wave heights in four areas, including Gangneung, Yangyang and Goseong in Gangwon, and Pohang in South Gyeongsang last Monday.

"We did not include Dokdo and Ulleung Island as those exposed to the risk of a tsunami based on our simulation," an official at the KMA said. "Tsunamis are more likely to occur along the coastal areas."

The east coast of the country is also vulnerable to underwater earthquakes.

According to the KMA, a total of 232 earthquakes occurred in the East Sea in less than two months, from April 23 to June 20 last year. That figure includes microearthquakes at or below the magnitude of 2.0.

The port of Samcheok in Gangwon seen damaged after a tsunami arrived due to a 7.7-magnitude earthquake that struck the west coast of Noshiro, Akita Prefecuture in Japan on May 26, 1983. One died and two went missing due to the tsunami. [KOREA INSTITUE OF OCEAN SCIENCE & TECHNOLOGY]

The consecutive earthquakes in the East Sea last year are suspected to be related to the 4.3-magnitude earthquake that occurred on April 19, 2019. The specific earthquake fault has likely been reactivated, according to the Korea Institute of Geoscience and Mineral Resources (Kigam).

The institute raised the possibility of the existence of a much larger fault zone and added that tsunamis and earthquake aftermath may occur if a 7.0-magnitude earthquake takes place in the same area. A 4.5-magnitude quake occurred in the area in May last year, worrying residents.

According to a KMA official, related institutes, including the Ministry of Oceans and Fisheries, are studying the faults for more information and investigating the cause of the consecutive underwater earthquakes in the East Sea last year.

However, detecting undersea earthquakes has become more difficult since the country's only bottom-ocean seismometer was scrapped in 2015 due to frequent malfunctions and high management costs. Experts suggest that conducting accurate studies on faults in the East Sea without such technology is challenging. Around 200 bottom-ocean seismometers are reportedly installed in the oceans near Japan.

Meanwhile, many stress the need for Korea to be prepared for potential tsunamis.

"The scale of earthquakes on the western coast of Japan may be smaller than those on the east coast, but many casualties resulted after a tsunami as high as 3 meters (10 feet) arrived in Samcheok of Gangwon in 1983 caused by a strong quake from Japan's west coast region," Kim Yeong-seog, a structural geology professor at Pukyong National University, said.

The Wolsong Nuclear Power Plant in Gyeongju, North Gyeongsang. [KOREA HYDRO & NUCLEAR CORP.]

Others point out that nuclear power plants in the country are not equipped with safe seismic designs. According to Lee Jeong-yoon, a former nuclear engineer and head of Nuclear Safety and Future, many nuclear power plants are not prepared for earthquakes.

"Nuclear power plants constructed in the past are designed to endure 0.2 force of peak ground acceleration [PGA]," Lee, who designed nuclear power plants during the 1980s to 1990s in places like Uljin County in North Gyeongsang, said.

PGA refers to the maximum acceleration of the ground that occurs when an earthquake takes place.

"But studies conducted on earthquake plates in the eastern south areas show that quakes exceeding 0.2 force may take place in the region and that if powerful quakes near the coastal region of Japan take place, as recently occurred, they will bring big tsunamis to the east coast area," Lee said.

State-run nuclear power company Korea Hydro & Nuclear Power, which maintains nuclear power plants in the country, holds that domestic power plants are well prepared for such disasters.

"The standard for seismic designs of power plants in Korea is similar or even higher to that of the mid-eastern regions of the U.S. and Europe, where quake activities are similar to the country," an official at the state-run company said.

"The PGA measured at the Wolsong Nuclear Power Plant during the largest 5.8-magnitude earthquake that occurred in Gyeongju in 2016 was reported to be less than half of its seismic design’s maximum endurance level."

BY JEONG EUN-HYE, CHO JUNG-WOO [cho.jungwoo1@joongang.co.kr]