Third Navy ship shock trial off Florida also registered as earthquake
Last month, two U.S. Navy explosions off the coast of Florida triggered earthquake-like activity on seismographs as far away as Venezuela. Now researchers have found a third test explosion had a similar effect.
At first, the U.S. Geological Survey’s maps only showed two events, but all three ship shock trials carried out on the USS Jackson registered on seismographs.
The previously unreported event — June 23 — registered the strongest, at 3.8 on the Richter scale. That event was centered about 105 miles east-northeast of Ormond-by-the-Sea, according to the Geological Survey.
Ship shock trials are carried out on new classes of Navy ships to determine whether the ship would remain seaworthy in battle. Each of the shock trials, on June 10, June 23 and July 16, used a 10,000-pound charge, Navy officials have previously confirmed. The USGS earthquake map now includes all three events, labeling them "experimental explosions."
The closest trial was June 10, about 97 miles east-northeast of Flagler Beach, and the July 16 blast was about 104 miles east-northeast of Daytona Beach Shores.
The Navy plans a "full analysis" of the shock trials on the Jackson and their process, including communication with external agencies, before the planned full ship shock trials for the USS Milwaukee take place either later this summer or in early fall, said Dale Eng, a public information officer for the Navy’s Sea Systems Command in Washington.
The Navy obtained the required permits from the National Oceanic and Atmospheric Administration’s Fisheries Service for the testing, and deployed a number of marine mammal observers across the area to watch for whales and other animals before the explosions. Similar tests conducted on the USS Mesa Verde in 2008 didn't note any impact to marine mammals.
State wildlife officials noticed a slight uptick in the number of marine mammals that stranded along Northeast Florida beaches following the last blast. However, Fisheries Service spokeswoman Allison Garrett said there was nothing to indicate the recent marine mammal deaths were related to the testing.
The animals were species that commonly strand along the coast and the overall stranding numbers for the year have not increased, she said.
The list of animals collected by the Florida Fish and Wildlife Conservation Commission over the past couple of weeks included a pygmy sperm whale, a pygmy sperm whale calf, and an unidentified dwarf or pygmy sperm whale in Nassau and St. Johns counties, an emaciated juvenile dolphin in Flagler County and a dolphin in Volusia County, according to officials with FWC and Volusia County. There were also unconfirmed reports of a dolphin and shark in the surf zone in Nassau County later in the week, but the animals were never found, said the FWC's Nadia Gordon.
“For us, it was a lot in a week,” said Gordon. Additionally, they also found what appeared to be “whale parts,” including a lung and partial liver.
It’s the time of year when dead animals tend to decompose quickly, making it more difficult to figure out why they died, she said. “In this heat in Florida, it can be difficult to get fresh dead carcasses.” Scientists took tissue samples from the animals, which will be sent for further testing.
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