What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED DUE TO: IN THE CLIMB GOT VIBRATIONS IN THE FLOOR AND SOUNDS LIKE A LAWN MOWER OR A RAT DEPLOYMENT. HEARD IN THE COCKPIT AND THE CABIN. FLIGHT ATTENDANT REPORTED VIBRATIONS ALSO IN THE FLOOR. AIRCRAFT AIR INTERRUPTED BACK TO AND LANDED SAFELY AT PHX. INSPECTED AIRCRAFT FOUND POWER DOOR OPENED AND NOT LATCH. RESECURED DOOR, OPS CHECK AND FIT CHECK NOSED DOOR AS REQUIRED. PER AMM 05-51-67.