Earthquake.now

M5.2 Earthquake near Ōyama, Japan — 23 December 2025

A moderate earthquake of magnitude 5.2 was recorded near Ōyama, Japan on , with an epicentre 163 km south of Ōyama, at a focal depth of 336.9 km. It ranked as the 15th strongest of 81 earthquakes recorded in Japan in the preceding 30 days.

5.2 Moderate

Time (UTC): 2025-12-23 09:44:21

Time (your timezone): —

Magnitude: 5.2 (moderate)

Focal depth: 336.9 km (deep)

Epicentre: 33.1492, 137.9360

Location: 163 km S of Ōyama, Japan

Country: Japan

USGS link to NOAA tsunami information: Not linked

Review status: Reviewed

Source: USGS event page

How strong was this earthquake?

Moderate earthquakes can damage poorly built or unreinforced structures near the epicentre, while well-engineered buildings typically escape serious harm. Shaking is often strong enough to wake sleeping residents over a wide area.

A magnitude 5.2 earthquake radiates roughly 951 tons of TNT equivalent in seismic energy.

The USGS assigns this earthquake a significance score of 416, 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 18:56 local solar time at the epicentre, in the evening.

This event was deeper than 93% of the 1,221 earthquakes recorded in Japan in our catalogue and stronger than 90% of them.

Where was the epicentre?

The epicentre was located at 33.1492, 137.9360 — 163 km south of Ōyama. The closest other recorded event was a magnitude 4.2 earthquake 16 km east of here on 30 June 2025.

The nearest other settlements in our records are Shima (57 km north-northwest), Kumano (102 km west-northwest), Iwata (112 km north) and Shimoda (134 km east-northeast).

Why the 337 km depth matters

At 337 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 can be felt widely and may cause minor local damage. 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 M5.2 it falls below the magnitude 6.5 threshold that generally applies before a submarine earthquake displaces enough water to generate a damaging tsunami; its 337 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.

33 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 5.8 event near Shingū on 26 February 2025. This M5.2 event released about 7.9 times less energy than that event.

5 earthquakes have been recorded within 100 km of this epicentre in the past year, 1 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 December 2025 worldwide record, and of earthquakes in Japan during December 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 5 earthquakes worldwide

All magnitude 5 earthquakes →

Questions about this earthquake

How strong was the earthquake near Ōyama?

It measured magnitude 5.2 — a moderate earthquake. A magnitude 5.2 earthquake radiates roughly 951 tons of TNT equivalent in seismic energy.

How deep was the earthquake near Ōyama?

The focus was 337 km below the surface, which counts as deep.

Was the Ōyama earthquake felt at the surface?

At magnitude 5.2 and a focal depth of 337 km, the depth spreads the energy out, so shaking is weaker overhead but reaches further.

When did the earthquake near Ōyama happen?

23 December 2025 at 09:44 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 Ōyama?

33 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 5.8 event near Shingū on 26 February 2025. This M5.2 event released about 7.9 times less energy than that event.