An unusual ‘experimental explosion’ entry appeared on the government’s earthquake tracking website, sparking questions about the mysterious event.
The US Geological Survey detected a 3.9 magnitude earthquake east of Ponce Inlet, just south of Daytona Beach, at 3.04pm ET on Thursday.
The event was listed with a depth of 0 feet, indicating the seismic source was at or very near the surface, a characteristic more consistent with an explosion than a typical tectonic earthquake.
Meteorologist Nic Merianos with CBS Miami said on X that he has ‘never seen this before.’
A USGS spokesperson told the Daily Mail: ‘The recorded ground motions from this event are more typical of an explosion than a naturally occurring earthquake.
‘The Navy has conducted Full Ship Shock Trials (FSST) in this region in the past.’
The Navy periodically conducts these controlled underwater detonations to test how new or upgraded warships, like aircraft carriers or combat ships, withstand battle-like explosions near mines or torpedoes.
In 2021, a similar event was detected in the same location when the US Navy set off a test explosion near its new aircraft carrier, the USS Gerald R Ford.
The US Geological Survey detected a 3.9 magnitude earthquake east of Ponce Inlet, just south of Daytona Beach, at 3.04pm ET
While military testing was the likely cause for the experimental explosion reading on USGS, the public was alarmed by the alert.
‘What type of experimental explosion generates a 3.9 earthquake?’ one X user posted.
Others speculated there was a bomb testing off the Florida coast.
These US Navy tests use large explosive charges, such as tens of thousands of pounds in past cases, to simulate battle conditions like nearby mines or torpedoes and test warship resilience.
No damage or injuries are expected or reported, these are planned, permitted tests with environmental considerations for marine life.
The event in 2021 is known as a ‘shock trial,’ an explosion meant to test the USS Gerald R Ford’s ability to withstand nearby detonations.
The Navy has been conducting these tests for decades after discovering that nearby explosions can knock out critical ship systems without inflicting significant physical damage.
The aircraft carrier was designed using advanced computer modeling, extensive testing and engineering analysis to withstand the shock of combat.
The USGS said: ‘The Navy has conducted Full Ship Shock Trials (FSST) in this region in the past.’ Pictured is a testing in 2021
The Full Ship Shock Trial helps confirm those designs by measuring how the vessel performs when subjected to a powerful nearby underwater explosion.
The Navy has carried out Full Ship Shock Trials for decades on newly built warships.
Recent tests have included the littoral combat ships USS Jackson and USS Milwaukee in 2016, the amphibious transport dock USS Mesa Verde in 2008, the amphibious assault ship USS Wasp in 1990, and the guided missile cruiser USS Mobile Bay in 1987.
The last aircraft carrier to undergo the trial was the USS Theodore Roosevelt in 1987.
