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M4.6 Earthquake near Saipan, Northern Mariana Islands — 27 September 2025

A light earthquake of magnitude 4.6 was recorded near Saipan, Northern Mariana Islands on , with an epicentre 153 km east-southeast of Saipan, at a focal depth of 10.0 km. It was the strongest of the 2 earthquakes recorded in the Northern Mariana Islands in the preceding 30 days.

4.6 Light

Time (UTC): 2025-09-27 12:47:03

Time (your timezone): —

Magnitude: 4.6 (light)

Focal depth: 10.0 km (shallow)

Epicentre: 14.5367, 147.0050

Location: 153 km ESE of Saipan, Northern Mariana Islands

Country: Northern Mariana Islands

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 22:35 local solar time at the epicentre, late at night.

This event was shallower than 99% of the 68 earthquakes recorded in the Northern Mariana Islands in our catalogue and stronger than 38% of them.

Where was the epicentre?

The epicentre was located at 14.5367, 147.0050 — 153 km east-southeast of Saipan. The closest other recorded event was a magnitude 4.8 earthquake 12 km northeast of here on 17 August 2026.

The nearest other settlements in our records are San Jose Village (78 km south-southwest), Yigo Village (221 km south-southwest) and Inarajan Village (236 km southwest).

Why the 10 km depth matters

At 10 km this was a shallow earthquake. Shallow events release their energy close to the surface, so for a given magnitude they produce noticeably stronger shaking — and more damage — than deeper ones. Roughly three quarters of all earthquakes worldwide occur at shallow depths.

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 shallow focus makes stronger surface shaking more likely than for a deeper event of the same magnitude.

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; 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 4.8.

39 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 6.1 event near Yigo Village on 10 August 2025. This M4.6 event released about 178 times less energy than that event.

4 earthquakes have been recorded within 100 km of this epicentre in the past year, 0 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 September 2025 worldwide record, and of earthquakes in the Northern Mariana Islands during September 2025. Browse the full monthly archive to compare periods.

Nearest recorded earthquakes to this epicentre

Other recent earthquakes in the Northern Mariana Islands

All recorded earthquakes in the Northern Mariana Islands →

Other magnitude 4 earthquakes worldwide

All magnitude 4 earthquakes →

Questions about this earthquake

How strong was the earthquake near Saipan?

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 Saipan?

The focus was 10 km below the surface, which counts as shallow.

Was the Saipan earthquake felt at the surface?

At magnitude 4.6 and a focal depth of 10 km, shaking would have been concentrated near the epicentre.

When did the earthquake near Saipan happen?

27 September 2025 at 12:47 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 4.8.

How often do earthquakes happen near Saipan?

39 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 6.1 event near Yigo Village on 10 August 2025. This M4.6 event released about 178 times less energy than that event.