M 3.1 - 189 km SSE of Unalaska, United States
(189 km SSE of)Seismic Telemetry Specifications
3.1ML
Minor Seismic Class
10.9km
Crustal Layer
52.2130° N
165.9290° W
reviewed
Net: AK
~674 kg
TNT Explosive Equiv.
Epicenter Location & Tectonic Fault Map
Is This Earthquake Dangerous?
A magnitude 3.1 event is classified as a minor earthquake. Often felt by people indoors, especially on upper floors. Hanging objects may swing slightly; structural damage is extremely rare.
Estimated Shaking Radius
~25–50 km
Potential Damage Zone
None
Focal Depth Effect
High Surface Energy
What Does Magnitude 3.1 Mean?
Earthquake strength is measured on a logarithmic scale. Compare this event with the full seismic scale:
Logarithmic Energy Multiplier
Because seismic scales are logarithmic, each whole integer increase represents:
10× Ground Motion Amplitude
The seismograph wave amplitude jumps by tenfold for every 1.0 magnitude step.
~31.6× Radiated Kinetic Energy
Total energy release increases exponentially (101.5 ≈ 31.62 times per magnitude unit).
Why Did This Earthquake Happen?
The western North American margin is shaped by the Pacific Ring of Fire, including the 800-mile San Andreas transform fault system and the Cascadia Subduction Zone. Lateral strike-slip motion between the Pacific and North American plates drives continuous crustal deformation across the region.
Originating at a depth of 10.9 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.
Earthquake Safety Action Plan
- •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.
- •Inspect utilities for damaged gas lines, water leaks, or electrical hazards.
- •Expect Aftershocks: Secondary tremors frequently strike after moderate and strong events.
- •Avoid damaged structures and listen to official emergency broadcasts.
- •Maintain a 72-hour emergency go-bag with water, non-perishable food, and first aid.
- •Anchor heavy furniture, water heaters, and appliances to structural wall studs.
- •Establish a family emergency communication protocol and meeting point.
Did You Feel This Earthquake?
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