3.9 magnitude earthquake measured off Florida’s east coast

PONCE INLET, Fla. — A reported 3.9 magnitude earthquake off the Florida’s east coast Friday was actually an “experimental explosion,” the U.S. Navy confirmed.

A spokesperson with the Navy told Action News Jax that what was measured were a result of military “shock trials” and they are not unusual, nor is it unusual for them to register as earthquakes.

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Shock trials test a ship to see how it holds up in an undersea explosion. This is to test strength of the ship’s hull, making sure it can perform in battle.

The United States Geological Survey measured the seismic event roughly 100 miles off the coast of Ponce Inlet.

Action News Jax has reached out to the Coast Guard for more information.