Kathleen Danise was hurled from her beach chair near the water line and thrown against a rock jetty 10 feet away.
A loud boom that knocked a Rhode Island beachgoer out of her chair is still a mystery days later, leaving investigators and scientists wondering whether it was a bizarre case of nature acting up.
Among the theories being considered is some kind of seismic event, or a methane explosion.
Saturday's blast at Salty Brine beach in Narragansett was so strong that Kathleen Danise was hurled from her beach chair near the water line and thrown against a rock jetty 10 feet away. Danise's family says the 60-year-old Waterbury, Connecticut woman suffered two fractured ribs and bruises.
Witnesses say they heard rumbling and a loud bang that sounded like a large firecracker, grenade, or gas explosion.
State Police Colonel Steven G. O'Donnell says there is no physical evidence of an explosion.