Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 200; Flight Crew Total 14000; Flight Crew Type 4030
Flight Deck / Cabin / Aircraft Event Illness / Injury; Inflight Event / Encounter Wake Vortex Encounter
General Physical Injury / Incapacitation
Environment - Non Weather Related
We were descending through 15;000 FT near GRAMM Intersection on the RIIVR2 arrival into LAX. Autopilot and seatbelt sign were both on. We encountered wake turbulence with caused one moderate jolt including a 10 degree roll to the right. One other jolt occurred seconds later. We asked ATC what aircraft we were following. SCT said we were following a B747 eleven miles ahead. Flight Attendant was in the aisle picking up trash. She said she went to the floor. Upon landing I was informed by her of the event and that she was feeling a mid-back pain. She did not ask for medical assistance at the time; but feared she would be sore the next day and would therefore be filing a report.
Air Carrier Captain reported encountering wake vortex 11 miles in trail of a B747 on approach to LAX; resulting in turbulence and roll. One Flight Attendant reported back pain as a result.