Earthquake.now

M4.6 Earthquake near Houma, Tonga — 23 August 2025

A light earthquake of magnitude 4.6 was recorded near Houma, Tonga on , with an epicentre 267 km west-northwest of Houma, at a focal depth of 506.6 km. It ranked as the 14th strongest of 17 earthquakes recorded in Tonga in the preceding 30 days.

4.6 Light

Time (UTC): 2025-08-23 20:38:44

Time (your timezone): —

Magnitude: 4.6 (light)

Focal depth: 506.6 km (deep)

Epicentre: -20.2429, -177.6710

Location: 267 km WNW of Houma, Tonga

Country: Tonga

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 4.6 earthquake radiates roughly 120 tons of TNT equivalent in seismic energy.

The USGS assigns this earthquake a significance score of 326, 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 08:48 local solar time at the epicentre, during the morning.

This event was deeper than 91% of the 416 earthquakes recorded in Tonga in our catalogue and stronger than 38% of them.

Where was the epicentre?

The epicentre was located at -20.2429, -177.6710 — 267 km west-northwest of Houma. The closest other recorded event was a magnitude 4.2 earthquake 7 km north-northeast of here on 12 June 2026.

The nearest other settlements in our records are Levuka (145 km west-northwest), Pangai (205 km east) and Neiafu (277 km northeast).

Why the 507 km depth matters

At 507 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 M4.6 it falls below the magnitude 6.5 threshold that generally applies before a submarine earthquake displaces enough water to generate a damaging tsunami; its 507 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

2 further earthquakes have been recorded within about 150 km of the epicentre in the seven days after this event, the largest of them magnitude 5.4.

271 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 6.3 event near Fiji region on 01 March 2026. This M4.6 event released about 355 times less energy than that event.

38 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 August 2025 worldwide record, and of earthquakes in Tonga during August 2025. Browse the full monthly archive to compare periods.

Nearest recorded earthquakes to this epicentre

Other recent earthquakes in Tonga

All recorded earthquakes in Tonga →

Other magnitude 4 earthquakes worldwide

All magnitude 4 earthquakes →

Questions about this earthquake

How strong was the earthquake near Houma?

It measured magnitude 4.6 — a light earthquake. A magnitude 4.6 earthquake radiates roughly 120 tons of TNT equivalent in seismic energy.

How deep was the earthquake near Houma?

The focus was 507 km below the surface, which counts as deep.

Was the Houma earthquake felt at the surface?

At magnitude 4.6 and a focal depth of 507 km, the depth spreads the energy out, so shaking is weaker overhead but reaches further.

When did the earthquake near Houma happen?

23 August 2025 at 20:38 UTC.

Was there a tsunami?

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

Have there been aftershocks?

2 further earthquakes have been recorded within about 150 km of the epicentre in the seven days after this event, the largest of them magnitude 5.4.

How often do earthquakes happen near Houma?

271 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 6.3 event near Fiji region on 01 March 2026. This M4.6 event released about 355 times less energy than that event.