The answer to 'why is my outlet sparking' is that a sparking outlet is typically caused by a loose or damaged electrical connection. This can happen when the outlet is old, the wiring is loose, or there is a problem with the circuit.
Sparking outlets are a serious fire hazard and should be addressed immediately. If you notice any sparking, flickering, or other issues with an outlet, stop using it right away and call an electrician. Attempting to fix a sparking outlet yourself can be very dangerous and should only be done by a professional.