Live Seismic Telemetry • REVIEWED Event

Light 4.6 Earthquake Near Chignik, United States

6013 days agoThursday, April 1, 2010 at 01:46:55 PM UTC

A light magnitude 4.6 earthquake struck 104 km E of Chignik, United States on Thursday, April 1, 2010 at 01:46:55 PM UTC. This intermediate focal depth (75.6 km depth) released energy equivalent to approximately 120 tons of TNT. Here is the verified AK telemetry, live epicenter map, and ground shaking assessment.

4.6MAG
Light EarthquakeIntermediate Focal Depth
Chignik, United StatesUnited States(104 km E of)

Seismic Telemetry Specifications

Magnitude

4.6MB

Light Seismic Class

Focal Depth

75.6km

Upper Mantle

Epicenter

56.360° N, 156.715° W

GPS Coordinates

Energy Yield

120 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 4.6 event is classified as a light earthquake. Noticeable shaking of indoor objects and rattling doors/windows. Generally causes none to slight non-structural damage in older buildings.

Estimated Shaking Radius~50–100 km
Potential Damage Zone< 15 km (very minor)
Focal Depth EffectModerate Damping

Estimated Shaking Across Nearby Communities

Chignik, United States104 km (64.6 mi) W

Felt indoors. Hanging objects swing slightly. Vibration like a passing light truck.

MMI IIIWeak

Did You Feel This Earthquake?

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What Does Magnitude 4.6 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
This Event
5.0 – 5.9Moderate
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 &approx; 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 75.6 km (Upper Mantle / Wadati-Benioff Zone (70–300 km)), this rupture occurred originated within the descending oceanic plate inside the upper mantle. shaking radiates over a wider geographic area with attenuated high frequencies.

Aftershock Outlook & Secondary Tremors

Seismologists note that minor aftershocks remain common in the 24 to 48 hours following tremors of magnitude 4.6. According to statistical seismic models, there is roughly a 5% probability of a subsequent event of equal or greater strength occurring in the same fault zone. Residents in United States are advised to check living spaces for unsecured items.

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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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