Live Seismic Telemetry • REVIEWED Event

Light 4.7 Earthquake Near Fern Forest, United States

5347 days agoMonday, January 23, 2012 at 02:36:32 AM UTC

A light magnitude 4.7 earthquake struck 16 km S of Fern Forest, United States on Monday, January 23, 2012 at 02:36:32 AM UTC. This shallow crustal event (8.0 km depth) released energy equivalent to approximately 163 tons of TNT. Here is the verified HV telemetry, live epicenter map, and ground shaking assessment.

4.7MAG
Light EarthquakeShallow Crustal Event
Fern Forest, United StatesUnited States(16 km S of)

Seismic Telemetry Specifications

Magnitude

4.7ML

Light Seismic Class

Focal Depth

8.0km

Crustal Layer

Epicenter

19.321° N, 155.121° W

GPS Coordinates

Energy Yield

163 tons

TNT Equivalent Power

Network Source

HV

USGS Real-time Feed

Epicenter Location & Tectonic Fault Map

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Is This Earthquake Dangerous?

A magnitude 4.7 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 EffectHigh Surface Energy (Crustal)

Estimated Shaking Across Nearby Communities

Fern Forest, United States16 km (9.9 mi) N

Felt by all. Glassware broken, books knocked off shelves, minor plaster cracks.

MMI VIStrong

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What Does Magnitude 4.7 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 8.0 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

Seismologists note that minor aftershocks remain common in the 24 to 48 hours following tremors of magnitude 4.7. 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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