You probably should get rid of it. Aerial ace would be good, but earthquake can deal with fighting types. No one knows why, but it is a physical move, so it will actually do more than aerial ace.(Earthquakes attack power is 100 compared to aerial ace's 60). Always remember, tyranitar is a dark/rock type.
Protect would be a good move, since your ability is sand stream.
Always take advantage of abilities:)