A tsunami advisory was in place for the coast of Miyazaki Prefecture on Thursday after a magnitude 7.1 earthquake, registering a lower 6 on the Japanese seismic intensity scale, struck off Kyushu’s coast, the Meteorological Agency said.
Waves of up to 1 meter could reach the coast. Tsunami waves can arrive repeatedly, and the agency warned people to stay away from the coast until advisories are lifted.
Small waves have already been recorded in some areas. A 50 cm tsunami reached Miyazaki Port at 5:14 p.m., a 40 cm wave reached Aburatsu Port on the Nichinan coast in Miyazaki at 5:23 p.m., and a 30 cm wave reached Tosashimizu in Kochi at 5:46 p.m.
Chief Cabinet Secretary Yoshimasa Hayashi said three people have been injured, and that a landslide was reported in the city of Shibushi in Kagoshima Prefecture.
The tsunami advisory initially covered a wider area, including Ehime, Kochi, Oita, and Kagoshima prefectures, but was updated to only include Miyazaki at about 7 p.m.
Later Thursday, the Meteorological Agency issued its first-ever alert warning about a possible large earthquake around the Nankai Trough. It is believed that the chance of a major earthquake occurring in the Nankai Trough is relatively higher than usual, according to the agency.
Large-scale quakes in the Nankai Trough have historically caused severe damage, originating from the plate boundary region stretching from Suruga Bay to offshore Hyuganada, according to the Cabinet Office. Such earthquakes have occurred in cycles of 100 to 150 years.
According to a 2022 evaluation by the Headquarters for Earthquake Research Promotion, there is a 70% to 80% probability of a magnitude 8 to 9 class earthquake occurring within the next 30 years.
Thursday’s quake, with its epicenter in the Hyuganada sea off the coast of Miyazaki Prefecture, struck at 4:43 pm. at a depth of 30 kilometers.
At a news conference following the quake, the agency cautioned that people in the affected areas should be on alert for earthquakes measuring up to lower 6 for the next week, especially over the next two or three days.
In areas where tremors were strongly felt, the risk of buildings collapsing and of landslides has increased, the agency added, warning people to stay vigilant surrounding quake activity and rainfall.
After the quake, Prime Minister Fumio Kishida instructed the authorities to share accurate information about the tsunami warning and any damage, urging residents to take necessary precautions to find shelter.
The government set up a task force under the helm of disaster management minister Yoshifumi Matsumura, Kishida told reporters Thursday evening.
“I urge everyone to check information from the government, go back to basic disaster preparedness and get ready to evacuate immediately in the event of an earthquake,” Kishida said in reference to the risk of a Nankai Trough earthquake, urging people to refrain from spreading misinformation.
On Friday, Kishida is scheduled to fly to Nagasaki to attend a ceremony to commemorate the 79th anniversary of the atomic bombing, and from there head directly to Kazakhstan for a four-day tour of Central Asia.
Kishida said he will judge whether to cancel these engagements or take further measures according to the developments of the next few hours.
Kyushu Electric Power said there was no impact on its Sendai and Genkai nuclear plants, located in the city of Satsumasendai in Kagoshima Prefecture and the Higashimatsuura district in Saga Prefecture, respectively.
Shikoku Electric Power said no shaking was detected at its Ikata Nuclear Power Plant in Ehime Prefecture — the only nuclear plant on Shikoku Island — adding that the plant’s Unit 3 has been shut down for routine inspections.
“The shaking was quite intense and lasted around 30 seconds,” a clerk at Miyazaki Airport told NHK. “We were told that some windows have shattered.”
Several domestic flights scheduled to depart Miyazaki Airport after 5:30 p.m. were canceled.
The Kyushu Shinkansen and Minami Kyushu Shinkansen lines resumed operations at around 5:25 p.m., NHK reported.
As of 19:54 p.m., several local lines across Kyushu were still suspended because of the earthquake.
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