downthrow

The entire country from this point to Sydney Heads has been slowly let down by one of those great earth movements known as a "downthrow fault."

The downthrow was not the work of one single act of disturbance—it went on for ages.

The relationship that exists between the hade and the direction of throw has led to the classification of faults into “normal faults,” which hade under the downthrow side, or in other words, those in which the hanging-wall has dropped; and “reversed faults,” which hade beneath the upthrow side, that is to say, the foot-wall exhibits a relative sinking.

The rock on that side of a fault which has dropped relatively to the rock on the other is said to be upon the downthrow side of the fault; conversely, the relatively uplifted portion is the upthrow side.

Again, a faulted mass may be on the downthrow side towards one end, and on the upthrow side towards the other, the movement having taken place about an axis approximately normal to the fault-plane, the “pivot” in this case being near the centre.