Earthquake.now

M4.2 Earthquake near Ambon, Indonesia — 20 August 2025

A light earthquake of magnitude 4.2 was recorded near Ambon, Indonesia on , with an epicentre 264 km south of Ambon, at a focal depth of 398.6 km. It ranked as the 64th strongest of 66 earthquakes recorded in Indonesia in the preceding 30 days.

4.2 Light

Time (UTC): 2025-08-20 10:43:34

Time (your timezone): —

Magnitude: 4.2 (light)

Focal depth: 398.6 km (deep)

Epicentre: -6.0515, 127.7500

Location: 264 km S of Ambon, Indonesia

Country: Indonesia

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 4.2 earthquake radiates roughly 30 tons of TNT equivalent in seismic energy.

The USGS assigns this earthquake a significance score of 271, 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 19:14 local solar time at the epicentre, in the evening.

This event was deeper than 97% of the 1,533 earthquakes recorded in Indonesia in our catalogue and stronger than 6% of them.

Where was the epicentre?

The epicentre was located at -6.0515, 127.7500 — 264 km south of Ambon. The closest other recorded event was a magnitude 4.4 earthquake 16 km west-southwest of here on 19 April 2026.

The nearest other settlements in our records are Maluku (173 km south), Lospalos (209 km south), Baukau (223 km southwest) and Amahai (228 km east-northeast).

Why the 399 km depth matters

At 399 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 M4.2 it falls below the magnitude 6.5 threshold that generally applies before a submarine earthquake displaces enough water to generate a damaging tsunami; its 399 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

1 further earthquakes have been recorded within about 150 km of the epicentre in the seven days after this event, the largest of them magnitude 4.2.

203 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 6.0 event near Lospalos on 24 August 2026. This M4.2 event released about 501 times less energy than that event.

18 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 Indonesia during August 2025. Browse the full monthly archive to compare periods.

Nearest recorded earthquakes to this epicentre

Other recent earthquakes in Indonesia

All recorded earthquakes in Indonesia →

Other magnitude 4 earthquakes worldwide

All magnitude 4 earthquakes →

Questions about this earthquake

How strong was the earthquake near Ambon?

It measured magnitude 4.2 — a light earthquake. A magnitude 4.2 earthquake radiates roughly 30 tons of TNT equivalent in seismic energy.

How deep was the earthquake near Ambon?

The focus was 399 km below the surface, which counts as deep.

Was the Ambon earthquake felt at the surface?

At magnitude 4.2 and a focal depth of 399 km, the depth spreads the energy out, so shaking is weaker overhead but reaches further.

When did the earthquake near Ambon happen?

20 August 2025 at 10:43 UTC.

Was there a tsunami?

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

Have there been aftershocks?

1 further earthquakes have been recorded within about 150 km of the epicentre in the seven days after this event, the largest of them magnitude 4.2.

How often do earthquakes happen near Ambon?

203 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 6.0 event near Lospalos on 24 August 2026. This M4.2 event released about 501 times less energy than that event.