# Why should this be a thrust fault?

Why should this figure represent a thrust fault?

I know this might be a stupid question, but I really want to understand. Since thrust faults are reverse faults why in the figure above if we turned the photo 90 degrees clockwise like this

we don't get the same shape as this

I think that in faults in general the fault plane is inclined to the horizontal, and the hanging wall is the mass of rocks above the fault plane, i.e., the side at which the angle between the fault plane and the horizontal is larger, and the foot wall is the mass of rocks below the fault plane, i.e., the side at which the angle between the fault plane and the horizontal is smaller. In the second figure, we have a hanging wall on the left side and we have a foot wall on the right side, and it seems that the hanging wall is moving down relative to the foot wall, and that's what happens in normal faults not reverse ones, right? So why we consider the thrust fault in figure one as a reverse fault?

• you do get the same shape, look at the bedding if you drilled through it, the bedding would be doubled, that is a thrust fault. It is a result of compression forces. You can't rotate the blocks without also rotating your orientation to the bedding planes.
– John
Commented Jun 13, 2017 at 21:44