Earthquakes in Japan — August 2025

41 earthquakes were recorded in Japan during August 2025, an average of 1.3 per day.

41 reached magnitude 4 or above and 9 reached magnitude 5 or above. The average focal depth was 111 km.

The month's largest event in Japan was a magnitude 5.9 earthquake near Yonakuni, Japan on 07 August 2025 at 07:45 UTC. A magnitude 5.9 earthquake radiates roughly 10,676 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 102 recorded the previous month.

61% of events here are shallow (under 70 km), 24% intermediate (70–300 km) and 15% 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 32 in the magnitude 4 range, 9 in the magnitude 5 range.

Activity peaked on 21 August, when 4 events were recorded.

The month's largest events were M5.9 near Yonakuni, Japan on 07 August at 109 km; M5.7 near Ōfunato, Japan on 21 August at 50 km; M5.6 near Takanabe, Japan on 16 August at 27 km.

That is 28% below the 57 events Japan averages per month across the 21 months on record.