On a Saturday, a 3.7 magnitude "earthquake" was detected about 168 miles off Florida's Daytona Beach Shores. It now appears that the quake was actually a "shock trial," an explosive test conducted by the US Navy to test the fortitude of the USS Jackson, a new combat ship. From the Daytona Beach News-Journal:
Asked about the reported earthquake on Monday, Dale Eng, a public information officer for the Navy's Sea Systems Command in Washington, said the Navy is working on a statement it expects to release this week.
Seismographs as far away as Minnesota, Texas and Oklahoma, as well as along the coast of Florida, Georgia and North Carolina, registered the event on Saturday, said Bruce Presgrave, a geophysicist and shift supervisor at the Geological Survey's National Earthquake Information Center in California.
(After being shown the above photo of a shock trial conducted last month) Presgrave said, "That's a smoking gun, isn't it?"
Presgrave planned to contact the Navy to learn more about the charges used in the shock trials as part of the agency's ongoing investigation.