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M4.5 Earthquake near Ninilchik, United States — 20 December 2024, 04:03 UTC

A light earthquake of magnitude 4.5 was recorded near Ninilchik, United States on , with an epicentre 48 km northwest of Ninilchik, at a focal depth of 84.7 km. It ranked as the 35th strongest of 9601 earthquakes recorded in the United States in the preceding 30 days.

4.5 Light

Time (UTC): 2024-12-20 04:03:22

Time (your timezone): —

Magnitude: 4.5 (light)

Focal depth: 84.7 km (intermediate)

Epicentre: 60.3570, -152.2940

Location: 48 km NW of Ninilchik, Alaska

Country: United States

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 4.5 earthquake radiates roughly 85 tons of TNT equivalent in seismic energy.

The USGS assigns this earthquake a significance score of 409, 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 17:54 local solar time at the epicentre, during the afternoon.

This event was deeper than 97% of the 155,627 earthquakes recorded in the United States in our catalogue and stronger than 100% of them.

Where was the epicentre?

The epicentre was located at 60.3570, -152.2940 — 48 km northwest of Ninilchik. The closest other recorded event was a magnitude 2.3 earthquake 6 km northeast of here on 12 September 2026.

The nearest other settlements in our records are Anchor Point (85 km south), Alaska Peninsula National Wildlife Refuge (243 km south-southwest) and Aleneva (247 km south-southwest).

Why the 85 km depth matters

At 85 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.

Read more on how focal depth changes what you feel →

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

132 further earthquakes have been recorded within about 150 km of the epicentre in the seven days after this event, the largest of them magnitude 2.8.

38 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 Susitna on 27 November 2025. This M4.5 event released about 178 times less energy than that event.

373 earthquakes have been recorded within 100 km of this epicentre in the past year, 370 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 December 2024 worldwide record, and of earthquakes in the United States during December 2024. Browse the full monthly archive to compare periods.

Nearest recorded earthquakes to this epicentre

Other recent earthquakes in the United States

All recorded earthquakes in the United States →

Other magnitude 4 earthquakes worldwide

All magnitude 4 earthquakes →

Questions about this earthquake

How strong was the earthquake near Ninilchik?

It measured magnitude 4.5 — a light earthquake. A magnitude 4.5 earthquake radiates roughly 85 tons of TNT equivalent in seismic energy.

How deep was the earthquake near Ninilchik?

The focus was 85 km below the surface, which counts as intermediate.

Was the Ninilchik earthquake felt at the surface?

At magnitude 4.5 and a focal depth of 85 km, the depth spreads the energy out, so shaking is weaker overhead but reaches further.

When did the earthquake near Ninilchik happen?

20 December 2024 at 04:03 UTC.

Was there a tsunami?

The USGS record carries a link to NOAA tsunami information for this event. That is not a warning: check your regional tsunami warning centre for any live alert.

Have there been aftershocks?

132 further earthquakes have been recorded within about 150 km of the epicentre in the seven days after this event, the largest of them magnitude 2.8.

How often do earthquakes happen near Ninilchik?

38 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 Susitna on 27 November 2025. This M4.5 event released about 178 times less energy than that event.