The Japan Meteorological Agency (JMA) said on November 9 that, following its monthly evaluation meeting on earthquakes along the Nankai Trough, no special change has been observed that would suggest the likelihood of a massive Nankai Trough earthquake has relatively increased compared to normal times ^[1]. The agency noted that, even in "normal" conditions, the probability of an M8-to-M9-class earthquake along the Nankai Trough within the next 30 years is already assessed as high, and that about 80 years have passed since the Showa Tonankai and Showa Nankai earthquakes, meaning the situation remains one of high urgency ^[1]. The next evaluation meeting is scheduled for December 7 ^[1].

Among recent observations, JMA noted an M5.2 earthquake off Hyuganada on October 25 and an M5.7 earthquake in eastern Aichi Prefecture on November 8, both of which it said do not indicate a special change in the locking condition of the plate boundary due to their scale ^[1]. The agency also reported slow-slip-related phenomena, including deep low-frequency tremors in western Shikoku and in the Tokai-to-northern-Kii-Peninsula area between late September and early November, accompanied by slight crustal deformation detected by strainmeters and tiltmeters ^[1]. Long-term crustal deformation differing from previous trends has been observed from western Shizuoka to eastern Aichi Prefecture since early 2022, and in western Shikoku since around summer 2026, which JMA attributes to long-term slow slip at the plate boundary ^[1]. Long-term subsidence trends continue around Omaezaki, Shionomisaki and Muroto Point, consistent with the ongoing subduction of the Philippine Sea Plate ^[1].JMA said these phenomena have all been repeatedly observed before, and overall, no data showing a special change in plate boundary locking conditions were obtained ^[1].

Separately, JMA announced on November 10 that, marking 80 years since the Showa Nankai earthquake on December 21, it will hold an online lecture on massive earthquake preparedness, live-streamed on December 20 from 13:30 to 16:00, with an archived version available from around January 2027 for about a year ^[2]. Live registration is capped at 1,000 people and is free, with sign-up details on JMA's special website, while the archived version will be viewable by anyone ^[2]. All sessions will include sign language interpretation, and topics include earthquake and tsunami information, disaster-prevention history, tsunami prediction, and how to communicate preparedness messages ^[2]. JMA's Weather Science Museum will also hold a free, no-reservation exhibition titled "80 Years Since the Showa Nankai Earthquake" from November 11 to January 11, open daily from 9:00 to 20:00 ^[2]. Readers should consult JMA's official announcements and the special website for registration and further details ^[1][2].

Source credit 出典：「南海トラフ地震関連解説情報について －最近の南海トラフ周辺の地殻活動－」（気象庁）（https://www.jma.go.jp/jma/press/2611/09a/nt20261109.html）、PDL1.0（https://www.digital.go.jp/resources/open_data/public_data_license_v1.0）を加工してJapan News (j.apan.news)が作成 出典：「巨大地震対策オンライン講演会・気象科学館企画展を開催します」（気象庁）（https://www.jma.go.jp/jma/press/2611/10a/20261110_lecture.html）、PDL1.0（https://www.digital.go.jp/resources/open_data/public_data_license_v1.0）を加工してJapan News (j.apan.news)が作成 This article is Japan News's own English summary of the Japanese original. It has been translated and edited by Japan News; it is not an official translation, and the Japan Meteorological Agency did not write or review it.