Why is a buzzing sound start hours after you cut your car off, around feul pump area

Hi, this is Bo, an auto expert on RepairPal's Car Genius team! The buzzing sound you hear near the fuel pump area after your Forester has been off for a while could be the evaporative emissions (EVAP) system running a self-test. This system pressurizes the fuel tank and lines to check for any leaks, which helps control emissions. It can start hours after you’ve parked the car and may run for a short time, even up to an hour. If you need any further advice or want help finding a trusted RepairPal shop in your area, please feel free to call us at 877-913-1554!