Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Provided Assistance; Flight Crew Took Evasive Action
Environment - Non Weather Related; Aircraft; Human Factors
While approaching to land in ROA Runway 24 we were being vector by ATC for a straight in approach. At 4;000 feet in level flight.  The aircraft was approximately 3.0 NM southeast of the final approach fix of HIBAN. ATC issued us a turn 'To a heading of 290 to intercept the GPS course. Cleared for the GPS Y Runway 24 approach.' Shortly afterwards the aircraft GPWS system activated with 'TERRIN TERRAIN PULL-UP.' Pilot flying disconnect the autopilot and climbed to approximately 4;700 feet. Then turn to the assigned heading and intercepted the GPS course and continued the decent to land into ROA. On the approach flight crew verified altitude and position and told what had occurred. ATC verified that the aircraft was at the appropriate altitude and position. They also added that their minimum vector altitude in the area that the aircraft was at was 4;000 feet. The flight continued the approach and landed safely on Runway 24.Still unsure on what the cause of the GPWS.
Air carrier Captain reported a CFTT event while on the GPS Y Runway 24 approach to ROA.