Last Thursday, a strong earthquake measuring 7.1 struck the southwest of Japan, prompting officials to assess injuries and structural damage while warning of strong aftershocks. By 8:30 a.m. local time, 13 people had been injured in Miyazaki, Kagoshima, and Kumamoto due to items falling or striking people during the quake. Miyazaki reported the highest number of injuries, with five cases. In Nichinan city, a gym used as an evacuation shelter lost its roof and had to remain closed for safety reasons.
The earthquake occurred at 4:43 p.m. local time (7:43 GMT) on Thursday, at a depth of 30 kilometers in the Hyuga Sea off Miyazaki’s coast, on the southern island of Kyushu. The Japan Meteorological Agency issued a tsunami warning for areas near the epicenter, with waves expected to reach up to one meter.
The first tsunami waves appeared at 5:01 p.m. (8:01 GMT) in Nichinan’s harbor, close to the epicenter, reaching 20 centimeters and then 40 centimeters in Aburatsu harbor, also in Nichinan.
In Miyazaki, the highest observed tsunami height reached half a meter in the port, with other locations along Shikoku and Kyushu recording waves around 30 centimeters in places like Tosashimizu, Shibushi, and Minamiosumi. No damages from the tsunami have been confirmed so far.
Regarding material damage, some homes in Kagoshima were reported collapsed, while in Nichinan, Miyazaki, a rock broke free and rolled onto a road but did not breach the guardrails.
In response, JR Central announced a reduction in train speeds on the Tokaido Shinkansen between Mishima and Mikawa as aftershocks of magnitude near 7 are anticipated in the coming days. Nuclear plant operators in the region reported no anomalies or damages at the Sendai and Ikata reactors.
Experts warn of possible aftershocks in the following days. The Japan Meteorological Agency noted that this event appears connected to the potential for a larger earthquake in the Nankai Trough, a region known for high seismic activity. Authorities urged heightened precautions and disaster-prevention measures, given the relatively higher likelihood of a large-scale earthquake with a center in that trough spanning from the Kanto area near Tokyo to Kyushu. This marks the first time an alert of this type has been issued.
The tremor occurs just days before the Obon holiday, observed from July 13 to 16 in Japan, a period when people honor their ancestors who have passed away.
Japan sits atop the so-called Ring of Fire, one of the most seismically active zones on the planet, and experiences frequent earthquakes. Consequently, the infrastructure is designed to withstand tremors and rapidly adapt to shifting conditions. The event underscores the ongoing need for readiness and resilient systems in seismically active regions. [Source: Japan Meteorological Agency, National authorities]