Earthquakes in Japan — October 2025

35 earthquakes were recorded in Japan during October 2025, an average of 1.1 per day.

35 reached magnitude 4 or above and 7 reached magnitude 5 or above. The average focal depth was 116 km.

The month's largest event in Japan was a magnitude 6.0 earthquake near Tomioka, Japan on 04 October 2025 at 15:21 UTC. A magnitude 6.0 earthquake radiates roughly 15,080 tons of TNT equivalent in seismic energy.

That is below the Japan monthly average of 57 events over the period we cover — a comparatively quiet month, and down from the 36 recorded the previous month.

66% of events here are shallow (under 70 km), 14% intermediate (70–300 km) and 20% deep-focus (over 300 km). That proportion of deep-focus events is the signature of a subduction zone: only a cold slab descending into the mantle stays brittle enough to rupture at those depths.

By band, the catalogue holds 28 in the magnitude 4 range, 6 in the magnitude 5 range, 1 in the magnitude 6 range.

Activity peaked on 24 October, when 4 events were recorded.

The month's largest events were M6.0 near Tomioka, Japan on 04 October at 47 km; M5.8 near Nemuro, Japan on 24 October at 41 km; M5.3 near Tatsugō, Japan on 07 October at 10 km.

That is 38% below the 57 events Japan averages per month across the 21 months on record.