TOKYO — A powerful earthquake struck off the southern coast of Japan on Thursday, prompting a tsunami advisory that urged residents to stay away from the coastline. Nine people were injured, mostly with minor injuries, but no reports of significant damage emerged.
The Japan Meteorological Agency stated that the earthquake registered a magnitude of 7.1 and was centered in waters off the eastern coast of Japan’s southern main island of Kyushu at a depth of about 30 kilometers (18.6 miles).
The quake most strongly shook Nichinan city and surrounding areas in Miyazaki prefecture on Kyushu island.
The agency reported that tsunami waves reaching up to 50 centimeters (1.6 feet) were detected along portions of Kyushu’s southern coast and the nearby island of Shikoku about half an hour after the earthquake struck. The tsunami advisory was lifted from most coastlines, excluding those along the Miyazaki prefecture.
Seismologists at the agency convened an emergency meeting to analyze whether the earthquake had affected the nearby Nankai Trough, the source of past devastating earthquakes. They subsequently issued an assessment indicating that the potential for a future earthquake in the region stretching from Kyushu to central Japan is higher than previously anticipated. The agency stated that it will continue to closely monitor plate movements near the Nankai Trough.
This does not imply an imminent threat of a major earthquake in the near future, but they urged residents on the coasts along the trough — which extends approximately 500 kilometers (310 miles) — to review their earthquake preparedness, University of Tokyo seismologist Naoshi Hirata, a member of an expert panel, told a joint news conference with JMA officials.
There is a 70-80% chance of an earthquake with a magnitude of 8 or 9 originating from the Nankai Trough within the next 30 years, Hirara said, adding that Thursday’s earthquake increases that probability, although the timing or exact location remains unpredictable.
The Fire and Disaster Management Agency reported nine injuries, primarily minor, sustained during Thursday’s earthquake in Miyazaki and neighboring Kagoshima due to falling or being struck by objects.
Chief Cabinet Secretary Yoshimasa Hayashi stated that officials were assessing potential injuries or severe damage, although none were immediately reported. He urged residents of the affected region to stay away from the coastline.
JMA Seismology Department official Shigeki Aoki warned that strong aftershocks could occur over the next week.
Japan’s NHK public television reported that windows were broken at the Miyazaki airport near the epicenter. The airport’s runway was temporarily closed for safety inspections.
NHK showed images of dozens of people gathering at a designated hilltop evacuation area.
In Osaki, located in neighboring Kagoshima prefecture, concrete walls collapsed, and a wooden house sustained damage, but no injuries were reported.
The Nuclear Regulation Authority said all 12 nuclear reactors, including three currently operating, on Kyushu and Shikoku remained safe.
Earthquakes in areas with nuclear power plants have been a significant concern since a massive earthquake and tsunami in March 2011 triggered the Fukushima nuclear disaster.
Japan sits on the Pacific “Ring of Fire,” a line of seismic faults encircling the Pacific Ocean, and is one of the world’s most earthquake-prone countries.
An earthquake on Jan. 1 in Japan’s north-central region of Noto resulted in the deaths of over 240 people.