M4.2 Earthquake near Port Alsworth, Alaska — 13 June 2025
A light earthquake of magnitude 4.2 was recorded near Port Alsworth, Alaska on , with an epicentre 50 km east of Port Alsworth, at a focal depth of 159.7 km.
Time (UTC): 2025-06-13 19:17:06
Time (your timezone): —
Magnitude: 4.2 (light)
Focal depth: 159.7 km (intermediate)
Epicentre: 60.1166, -153.4200
Location: 50 km E of Port Alsworth, Alaska
USGS link to NOAA tsunami information: Available
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 306, 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.
Where was the epicentre?
The epicentre was located at 60.1166, -153.4200 — 50 km east of Port Alsworth. The closest other recorded event was a magnitude 0.9 earthquake 2 km west of here on 29 July 2026.
Why the 160 km depth matters
At 160 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 is often felt across the surrounding area. Its intermediate depth normally reduces peak shaking near the epicentre compared with a shallow event of the same magnitude.
What does the tsunami information flag mean?
The USGS event record links to NOAA tsunami information because this was a large event in an oceanic region. That link flag does not mean a tsunami occurred or that a warning is active. Check tsunami.gov and instructions from your local authority for the current status of your coastline.
How earthquakes generate tsunamis, and what the alert levels mean →
Aftershocks and local seismic history
101 further earthquakes have been recorded within about 150 km of the epicentre in the seven days after this event, the largest of them magnitude 2.5.
27 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 4.5 event near Port Alsworth on 06 January 2026. This M4.2 event released about 2.8 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 June 2025 worldwide record. Browse the full monthly archive to compare periods.
Nearest recorded earthquakes to this epicentre
- M0.9 earthquake near Port Alsworth, Alaska — (2 km W)
- M-0.7 earthquake near Pedro Bay, Alaska — (17 km ESE)
- M0.5 earthquake near Port Alsworth, Alaska — (18 km ENE)
- M1.5 earthquake near Pedro Bay, Alaska — (18 km SE)
- M-0.8 earthquake near Pedro Bay, Alaska — (18 km SE)
- M0.2 earthquake near Pedro Bay, Alaska — (19 km ESE)
- M1.4 earthquake near Pedro Bay, Alaska — (20 km ESE)
- M-0.8 earthquake near Pedro Bay, Alaska — (20 km ESE)
- M-0.7 earthquake near Pedro Bay, Alaska — (20 km ESE)
- M0.4 earthquake near Pedro Bay, Alaska — (21 km ESE)
Other magnitude 4 earthquakes worldwide
- M4.4 earthquake near El Arenal, Mexico —
- M4.3 earthquake near Puerto Madero, Mexico —
- M4.4 earthquake near Fiji region —
- M4.5 earthquake near Abepura, Indonesia —
- M4.1 earthquake near Charlotte Amalie, U.S. Virgin Islands —
- M4.0 earthquake near Charlotte Amalie, U.S. Virgin Islands —
- M4.2 earthquake near Banda Sea —
- M4.4 earthquake near Ollagüe, Chile —
Questions about this earthquake
How strong is a magnitude 4.2 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.
How deep was the earthquake near Port Alsworth?
At 160 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 M4.2 earthquake near Port Alsworth 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 is often felt across the surrounding area. 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 event record links to NOAA tsunami information because this was a large event in an oceanic region. That link flag does not mean a tsunami occurred or that a warning is active. Check tsunami.gov and instructions from your local authority for the current status of your coastline.
Have there been aftershocks?
101 further earthquakes have been recorded within about 150 km of the epicentre in the seven days after this event, the largest of them magnitude 2.5.
How often do earthquakes happen near Port Alsworth?
27 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 4.5 event near Port Alsworth on 06 January 2026. This M4.2 event released about 2.8 times less energy than that event.