Earthquake.now

M3.6 Earthquake near Brenas, Puerto Rico — 22 December 2025

A minor earthquake of magnitude 3.6 was recorded near Brenas, Puerto Rico on , with an epicentre 18 km north of Brenas, at a focal depth of 79.6 km. It ranked as the 7th strongest of 154 earthquakes recorded in Puerto Rico in the preceding 30 days.

3.6 Minor

Time (UTC): 2025-12-22 19:56:49

Time (your timezone): —

Magnitude: 3.6 (minor)

Focal depth: 79.6 km (intermediate)

Epicentre: 18.6315, -66.3328

Location: 18 km N of Brenas, Puerto Rico

Country: Puerto Rico

USGS link to NOAA tsunami information: Not linked

Review status: Reviewed

Source: USGS event page

How strong was this earthquake?

Minor earthquakes in this range are felt by people close to the epicentre as a brief jolt or rattle, but they very rarely cause any damage.

A magnitude 3.6 earthquake radiates roughly 3.8 tons of TNT equivalent in seismic energy.

The USGS assigns this earthquake a significance score of 200, 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 →

Where was the epicentre?

The epicentre was located at 18.6315, -66.3328 — 18 km north of Brenas. The closest other recorded event was a magnitude 2.9 earthquake 11 km south of here on 19 August 2026.

Why the 80 km depth matters

At 80 km this was an intermediate-depth earthquake. Energy from events at this depth spreads out before it reaches the surface, which usually means weaker shaking near the epicentre than a shallow quake of the same magnitude, but shaking felt across a wider area.

This catalogue does not ingest eyewitness responses, so it cannot confirm where this earthquake was felt. Based on magnitude alone, an event this size may be noticed locally, especially close to the epicentre. Its intermediate depth normally reduces peak shaking near the epicentre compared with a shallow 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 M3.6 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

36 further earthquakes have been recorded within about 150 km of the epicentre in the seven days after this event, the largest of them magnitude 3.5.

100 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 5.9 event near Punta Cana on 25 February 2025. This M3.6 event released about 2,818 times less energy than that event.

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 Puerto Rico during December 2025. Browse the full monthly archive to compare periods.

Nearest recorded earthquakes to this epicentre

Other recent earthquakes in Puerto Rico

All recorded earthquakes in Puerto Rico →

Other magnitude 3 earthquakes worldwide

All magnitude 3 earthquakes →

Questions about this earthquake

How strong is a magnitude 3.6 earthquake?

Minor earthquakes in this range are felt by people close to the epicentre as a brief jolt or rattle, but they very rarely cause any damage. A magnitude 3.6 earthquake radiates roughly 3.8 tons of TNT equivalent in seismic energy.

How deep was the earthquake near Brenas?

At 80 km this was an intermediate-depth earthquake. Energy from events at this depth spreads out before it reaches the surface, which usually means weaker shaking near the epicentre than a shallow quake of the same magnitude, but shaking felt across a wider area.

Was the M3.6 earthquake near Brenas felt?

This catalogue does not ingest eyewitness responses, so it cannot confirm where this earthquake was felt. Based on magnitude alone, an event this size may be noticed locally, especially close to the epicentre. Its intermediate depth normally reduces peak shaking near the epicentre compared with a shallow event of the same magnitude.

What does the USGS tsunami field mean for this event?

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 M3.6 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.

Have there been aftershocks?

36 further earthquakes have been recorded within about 150 km of the epicentre in the seven days after this event, the largest of them magnitude 3.5.

How often do earthquakes happen near Brenas?

100 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 5.9 event near Punta Cana on 25 February 2025. This M3.6 event released about 2,818 times less energy than that event.