WEST PALM BEACH, Fla. — Thirteen people were injured, two seriously, when an Eastern Airlines jet hit violent turbulence on a flight from Washington, D.C., to West Palm Beach, airline officials said today.

Flight 791 was at 31,000 feet when the DC-9 ran into turbulence about 130 miles north of West Palm Beach on Wednesday night, Eastern spokeswoman Karen Ceremsak said.

Passenger Betty Miller of Miramar, Fla., said, "It was like a whiplash on the end of something. It felt like we bought the farm."

Another passenger, Alison Levins, 33, of Boston, said the turbulence lasted about 30 seconds.