if you wanted to know whether a particular mountain was a formed by movement along a fault,what do you lookfor

Answer 1

Relationships between the structural geology of the area. Things like synclines and anticlines, horsts and grabens, thrust faults, etc. Once you catalog all the pieces, the puzzle is much easier to put together.

Answer 2

Slickensides. These are grooves in rocks due to fault movement. They run in the direction of fault movement and are used to determine relative movement (but that does not pertain to this question).