Live Seismic Telemetry • REVIEWED Event

Moderate 5.0 Earthquake Near Karluk, United States

1720 days agoThursday, December 30, 2021 at 01:24:36 PM UTC

A moderate magnitude 5.0 earthquake struck 47 km SW of Karluk, United States on Thursday, December 30, 2021 at 01:24:36 PM UTC. This shallow crustal event (58.6 km depth) released energy equivalent to approximately 477 tons of TNT. Here is the verified AK telemetry, live epicenter map, and ground shaking assessment.

5.0MAG
Moderate EarthquakeShallow Crustal Event Tsunami Advisory
Karluk, United StatesUnited States(47 km SW of)

Seismic Telemetry Specifications

Magnitude

5.0ML

Moderate Seismic Class

Focal Depth

58.6km

Crustal Layer

Epicenter

57.264° N, 155.004° W

GPS Coordinates

Energy Yield

477 tons

TNT Equivalent Power

Network Source

AK

USGS Real-time Feed

Epicenter Location & Tectonic Fault Map

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Is This Earthquake Dangerous?

A magnitude 5.0 event is classified as a moderate earthquake. Can cause slight to moderate damage to poorly constructed buildings. Felt widely across nearby communities within dozens of kilometers.

Estimated Shaking Radius~100–250 km
Potential Damage Zone~30–50 km
Focal Depth EffectHigh Surface Energy (Crustal)

Estimated Shaking Across Nearby Communities

Karluk, United States47 km (29.2 mi) N

Felt by many indoors. Dishes, windows rattle; walls make creaking sound.

MMI IVLight
Tsunami Advisory Active: A tsunami alert was generated for this event. Coastal residents should follow local disaster directives.

Did You Feel This Earthquake?

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6 people have reported shaking
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What Does Magnitude 5.0 Mean?

Earthquake strength is measured on a logarithmic scale. Compare this event with the full seismic scale:

1.0 – 2.9Micro
3.0 – 3.9Minor
4.0 – 4.9Light
5.0 – 5.9Moderate
This Event
6.0 – 6.9Strong
7.0 – 7.9Major
8.0+Great

Logarithmic Energy Multiplier

Because seismic scales are logarithmic, each whole integer increase represents:

10× Ground Motion Amplitude
The seismograph wave amplitude jumps tenfold for every 1.0 magnitude step.
~31.6× Radiated Kinetic Energy
Total energy release multiplies exponentially (101.5 ≈ 31.62 times per unit).

Why Did This Earthquake Happen?

United States's seismicity is fundamentally governed by its tectonic setting: Pacific Plate sliding past North American Plate along San Andreas; Juan de Fuca subducting along Cascadia; Pacific subduction along the Aleutian Trench. Major regional fault structures include San Andreas Fault System, Cascadia Subduction Zone, Aleutian Megathrust, Hayward Fault, New Madrid Seismic Zone.

Originating at a depth of 58.6 km (Earth's Crust (0–70 km)), this rupture occurred occurred within the brittle upper crust. shallow earthquakes produce the highest peak ground acceleration and the sharpest surface shaking.

Aftershock Outlook & Secondary Tremors

Following an earthquake of magnitude 5.0, an active aftershock sequence is expected over the coming days and weeks. In accordance with Omori's Law and Båth's Law of seismology, secondary tremors decrease in frequency over time, with the largest expected aftershock historically averaging approximately 1.0 to 1.2 magnitude units below the mainshock. Local residents should remain vigilant for secondary shaking, particularly when inspecting older structures or unreinforced masonry.

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Earthquake Safety Action Plan

Complete Safety Guide →
During the Shaking
  • Drop, Cover, and Hold On: Take cover beneath a sturdy table or desk.
  • Stay indoors away from exterior glass windows and heavy unanchored fixtures.
  • If outdoors, move into an open area away from power lines and building facades.
Immediately After
  • Inspect utilities for damaged gas lines, water leaks, or electrical hazards.
  • Expect Aftershocks: Secondary tremors frequently strike after significant events.
  • Avoid damaged structures and listen to official emergency broadcasts.
Preparation & Kits
  • Maintain a 72-hour emergency go-bag with water, food, and first aid.
  • Anchor heavy furniture, water heaters, and appliances to structural studs.
  • Establish a family emergency communication protocol and meeting point.

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