 Large scale images often unveil features that were difficult or impossible to see from previous available perspectives.Sudden 90 degree bends or jogs in a stream, or even an extended straight stretch could be possible indicators of a fault trace but when put into larger perspective can be aligned with other pieces of evidence to add confirmation.There could be a gentle elevation change that don't seem suspicious when walking over it, but when viewed remotely can show that it extends laterally in a straight line and could be evidence of an old fault scarp.