A significant earthquake with a magnitude of 7.1 hit off the southern coast of Japan on Thursday, resulting in primarily minor injuries and prompting increased concern about potential major quakes linked to the Nankai Trough located east of the region.
Officials reported nine individuals injured on Kyushu, Japan’s southern main island, mainly suffering from minor wounds. Fortunately, there were no reports of severe damage, and initial tsunami warnings following the quake were eventually rescinded.
In response to the quake, seismologists convened an emergency meeting to review and elevate the risk assessment of significant seismic activity along the Nankai Trough, known for historically triggering devastating earthquakes. The Japan Meteorological Agency (JMA) specified that the earthquake’s epicenter was approximately 30 kilometers (about 19 miles) beneath the sea surface, affecting areas such as Nichinan city in Miyazaki prefecture.
The agency recorded tsunami waves reaching heights of 50 centimeters (1.6 feet) along parts of Kyushu’s southern coast and nearby Shikoku about 30 minutes post-earthquake. Tsunami advisories were issued but were lifted for most regions within three hours and completely by five and a half hours later.
Following the quake, the JMA updated their predictions regarding the potential for future earthquakes in the area, noting a higher than previously anticipated likelihood of significant seismic events affecting the stretch from Kyushu to central Japan. Although immediate danger from a substantial quake is not expected, University of Tokyo seismologist Naoshi Hirata advised coastal residents to enhance their earthquake preparedness, given a 70-80% chance of an 8 or 9 magnitude quake from the Nankai Trough within the next three decades.
Prime Minister Fumio Kishida communicated that the government’s crisis management team would bolster disaster readiness and urged residents to remain attentive to official updates and avoid spreading misinformation. The Fire and Disaster Management Agency confirmed that most injuries involved minor incidents like falls or being struck by objects during the quake.
In terms of infrastructure, windows at Miyazaki airport were shattered, and the runway underwent temporary closure for safety inspections. Meanwhile, the “shinkansen” super-express trains quickly returned to regular service after conducting safety checks, while several local train lines suspended operations through Friday.
In Osaki, Kagoshima prefecture, some structural damage occurred, with concrete walls collapsing; however, no injuries were reported. The Nuclear Regulation Authority confirmed that all 12 nuclear reactors in Kyushu and Shikoku, including three active ones, were evaluated as safe following the quake.
Japan’s geographical positioning along the Pacific “Ring of Fire” makes it one of the countries most susceptible to earthquakes. A recent earthquake on January 1 in the north-central region of Noto resulted in over 240 casualties.