Earthquake.now

M4.0 Earthquake near Mikuni, Japan — 26 August 2025

A light earthquake of magnitude 4.0 was recorded near Mikuni, Japan on , with an epicentre 173 km northwest of Mikuni, at a focal depth of 364.5 km. It ranked as the 38th strongest of 38 earthquakes recorded in Japan in the preceding 30 days.

4.0 Light

Time (UTC): 2025-08-26 22:20:46

Time (your timezone): —

Magnitude: 4.0 (light)

Focal depth: 364.5 km (deep)

Epicentre: 37.4298, 134.9170

Location: 173 km NW of Mikuni, Japan

Country: Japan

USGS link to NOAA tsunami information: Not linked

Review status: Reviewed

Source: USGS event page

How strong was this earthquake?

Light earthquakes are widely felt near the epicentre and can rattle windows, dishes and hanging objects. Damage is uncommon and usually limited to cracked plaster or fallen loose items.

A magnitude 4.0 earthquake radiates roughly 15 tons of TNT equivalent in seismic energy.

The USGS assigns this earthquake a significance score of 246, which is below the USGS threshold of more than 600 for its significant-earthquake list. The ranking combines magnitude with available Did You Feel It responses and PAGER alert level; it is not a direct measurement of damage.

What the magnitude scale actually measures →

When it happened locally

That is about 07:20 local solar time at the epicentre, around dawn.

This event was deeper than 94% of the 1,223 earthquakes recorded in Japan in our catalogue and stronger than 0% of them.

Where was the epicentre?

The epicentre was located at 37.4298, 134.9170 — 173 km northwest of Mikuni. The closest other recorded event was a magnitude 4.3 earthquake 31 km west-southwest of here on 23 January 2025.

The nearest other settlements in our records are Anamizu (85 km east-northeast), Ama (106 km northwest), Hakui (137 km east-southeast) and Shika (144 km east-southeast).

Why the 364 km depth matters

At 364 km this was a deep-focus earthquake, occurring well inside the subducting slab rather than in the crust. Deep events are rarely damaging even at large magnitudes, though they can be felt over very long distances.

This catalogue does not ingest eyewitness responses, so it cannot confirm where this earthquake was felt. Based on magnitude alone, an event this size is often felt across the surrounding area. Its deep focus normally weakens surface shaking while spreading perceptible motion over a broad area.

Read more on how focal depth changes what you feel →

What does the tsunami information flag mean?

The USGS record does not carry a link to NOAA tsunami information. That field is not an all-clear and does not state whether a tsunami occurred. In this case, a damaging tsunami would be less likely because at M4.0 it falls below the magnitude 6.5 threshold that generally applies before a submarine earthquake displaces enough water to generate a damaging tsunami; its 364 km focal depth is too great to deform the sea floor significantly; it occurred inland rather than beneath the sea floor. For an active coastal alert, use tsunami.gov or your local warning authority.

How earthquakes generate tsunamis, and what the alert levels mean →

Aftershocks and local seismic history

No further earthquakes have been recorded within about 150 km of the epicentre in the seven days after this event.

18 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 5.1 event near Hakui on 14 December 2025. This M4.0 event released about 45 times less energy than that event.

4 earthquakes have been recorded within 100 km of this epicentre in the past year, 2 of them in the past 30 days.

How long aftershock sequences last, and how large they get →

Where this event sits in the record

This earthquake is part of the August 2025 worldwide record, and of earthquakes in Japan during August 2025. Browse the full monthly archive to compare periods.

Nearest recorded earthquakes to this epicentre

Other recent earthquakes in Japan

All recorded earthquakes in Japan →

Other magnitude 4 earthquakes worldwide

All magnitude 4 earthquakes →

Questions about this earthquake

How strong was the earthquake near Mikuni?

It measured magnitude 4.0 — a light earthquake. A magnitude 4.0 earthquake radiates roughly 15 tons of TNT equivalent in seismic energy.

How deep was the earthquake near Mikuni?

The focus was 364 km below the surface, which counts as deep.

Was the Mikuni earthquake felt at the surface?

At magnitude 4.0 and a focal depth of 364 km, the depth spreads the energy out, so shaking is weaker overhead but reaches further.

When did the earthquake near Mikuni happen?

26 August 2025 at 22:20 UTC.

Was there a tsunami?

No. The USGS record carries no tsunami-information link for this event.

Have there been aftershocks?

No further earthquakes have been recorded within about 150 km of the epicentre in the seven days after this event.

How often do earthquakes happen near Mikuni?

18 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 5.1 event near Hakui on 14 December 2025. This M4.0 event released about 45 times less energy than that event.