🌊 Nankai Trough: JMA Monthly Review Finds No Unusual Change

❓ What was announced?

The Japan Meteorological Agency (JMA) holds a monthly "Evaluation Committee on Earthquakes along the Nankai Trough" to review seismic activity and crustal movement in the region. The 109th meeting was held on September 7, 2026, and its findings were released the same day at 17:00 as the "Nankai Trough Earthquake Related Commentary Information." The conclusion: no unusual change has been observed that would suggest the likelihood of a major earthquake along the Nankai Trough is relatively higher than in normal times. Key observations reviewed this month: On August 2 at 04:10, an M5.3 earthquake occurred in Hyuganada at a depth of 21 km. Because it was a normal-fault event inside the Philippine Sea Plate, JMA assessed that its scale does not indicate any particular change in plate coupling. Deep low-frequency earthquakes (tremors) were recorded in western Shikoku (July 29–August 11), western Kii Peninsula (August 8–13), eastern Shikoku (August 9–15, and continuing since August 21), and central Kii Peninsula (August 24–27), accompanied by slight crustal movement on strainmeters and tiltmeters. These are attributed to short-term slow slip on the deep plate boundary and are phenomena that have been observed repeatedly in the past. Crustal movement seen from western Shizuoka to eastern Aichi since early 2022 is attributed to long-term slow slip, with the center of slip shifting from around the Atsumi Peninsula to the eastern side of Lake Hamana. Importantly, "no unusual change" does not mean "safe." JMA states that even in normal times the probability of an M8–M9 class Nankai Trough earthquake within the next 30 years is high, and that with roughly 80 years elapsed since the Showa Tonankai and Showa Nankai earthquakes, the situation remains urgent. The next committee meeting is scheduled for October 7, 2026.

👥 Who does this affect?

• ●Foreign residents on the Pacific side along the Nankai Trough — Shizuoka, Aichi, Mie, Wakayama, Tokushima, Kochi, Miyazaki and nearby areas
• ●Travelers visiting Osaka, Nagoya, Kyoto, Shikoku or Kyushu
• ●Foreign workers in coastal factories, farming and fishing, or the hotel industry
• ●Anyone who finds Japanese-language news hard to read and struggles to judge what quake bulletins mean
• ●Households with elderly members or small children who need extra time to evacuate

🌏 Impact on foreign residents and visitors

This announcement changes no rules for daily life. No evacuation or travel restrictions have been issued. Still, knowing what this bulletin is helps you stay calm when "Nankai Trough" trends on social media. JMA issues two kinds of Nankai Trough information: "Related Commentary Information," which reports the results of the monthly evaluation meeting, and "Extraordinary Information," which is issued when an abnormal phenomenon such as an M6.8-or-greater quake is observed in the assumed source region. This release is the former — a routine assessment. Put another way, now, while no extraordinary information is in effect, is exactly the time to get prepared. Earthquake information in Japan is delivered mainly in Japanese, but the JMA website has multilingual pages, and disaster apps deliver earthquake early warnings and tsunami warnings in several languages. For foreign residents and visitors, the biggest risk is not knowing where the evacuation site is or what a tsunami warning means. Travelers should check the evacuation route at their accommodation; residents should look at the multilingual hazard map distributed by their municipality — this month, not after the shaking starts.