Japan

Brief · 19 September 2026

This is the most recent brief; none has been generated since 19 September 2026. The event list below is current.

Japan experienced a sustained series of earthquakes over the past week, the most significant being an M5 quake with a red-level population exposure estimate of over 33.5 million people and 66 felt reports. Multiple other M4.6-M5.1 events struck across the country, including near Yudomari, Mutsu, Minami-Sōma, Tsunō, and Koseda, alongside continuing volcanic monitoring at Aira, Asosan, and Iwatesan.

Earthquake An M5 earthquake struck Japan at 77 km depth with an estimated population exposure of 33,534,158 and 66 felt reports, marked with a red severity level. Numerous other quakes in the M4.6-M5.1 range were recorded this week, including events southeast of Honshu, near Mutsu, Minami-Sōma, Tsunō, and Koseda, with population exposures ranging from roughly 7,400 to over 500,000.

Volcano Aira, Asosan, and Iwatesan volcanoes remain at green alert level, with Aira noted as continuing eruption activity and Asosan and Iwatesan showing continuing unrest.

Summarised from Hazardly's tracked events for the seven days to 19 September 2026 · no external sources. Generated by claude-sonnet-5 at 19 Sept, 20:42 UTC, not reviewed by a person before publication. Outbreak lines name the disease and country only; WHO's bulletin text is on each outbreak's event page.