Block diagram and map view for Question 7. Right Lateral Transform Fault.ģD interactive model of Figure 17: Figure 18. ![]() This is true no matter which block you are standing on, because it is relative motion! Sometimes, transform faults will be marked with the relative motion directions on either side of the fault (Figures 17 and 18). ![]() In a right-lateral transform fault, your friend on the opposite block moves towards your right. In a left-lateral transform fault, your friend on the opposite block moves towards your left. Imagine you are standing on one side of a transform fault looking across the fault to a friend on the other side. The fault plane can be vertical or at an angle ( Figures 17 and 18). In transform or strike-slip faults, one block moves laterally relative to the other block – it does not matter which one is the hanging wall or footwall. Thrust Fault.ģD interactive model of Figure 16: Transform or Strike-slip Faults Reverse Fault.Ī reverse fault that has a shallowly dipping fault plane (perhaps less than about 45 degrees) is called a thrust fault (Figure 16). In map view, the hanging wall rocks will be older than the footwall rocks, due to erosion of the uplifted side ( Figure 15). This motion can be determined by tracing the offset of the beds in a vertical motion in a block diagram. It is caused by shearing, which moves rock-blocks in two opposite, horizontal. In reverse faults, the hanging wall moves upwards relative to the footwall. In a strike-slip fault, blocks of rocks move horizontally past one another. Normal Fault.ģD interactive model of Figure 14: Reverse Faults In map view, the hanging wall rocks will be younger than the footwall rocks, due to erosion of the uplifted side. In normal faults, the hanging wall moves downward relative to the footwall ( Figure 13 and Figure 14). Block diagrams illustrating common types of faults: normal fault, reverse fault, strike-slip fault, and thrust fault. There are three main types of faults: normal faults, reverse faults, and transform or strike-slip faults. A good way to remember this is to imagine a mine tunnel running along a fault the hanging wall would be where a miner would hang a lantern and the footwall would be at the miner’s feet.įigure 13 (Click on link): Hanging wall, footwall, and scarp of a normal fault. In a dip-slip system, the footwallis below the fault plane and the hanging wall is above the fault plane. Dip-slip motion consists of relative up-and-down movement along a dipping fault between two blocks, the hanging wall and footwall. Normal and reverse faults display vertical, also known as dip-slip, motion. If it is visible at the surface, it is called a fault scarp (Figure 13). The fault splays are clearly delineated by valleys. The intersection of splay faults that trend northeast indicated by black dots. The master fault is a prominent linear feature immediately left of the snow line (black arrow, bottom). Strike-slip Fault Animation A left-lateral strike-slip fault is one on which the displacement of the far block is to the left when viewed from either side. An oblique view of Alpine Fault from the International Space Station. The San Andreas Fault is an example of a right lateral fault. The plane along which motion occurs is called the fault plane. strike-slip fault - a fault on which the two blocks slide past one another. Video showing motion in a strike-slip fault.īends along strike-slip faults create areas of compression or tension between the sliding blocks (see Chapter 2).Faults are the places in the crust where brittle deformation occurs as two blocks of rocks move relative to one another. ![]() If the opposing block moves right, it is dextral motion. If the block on the opposing side of the fault moves left relative to the observer’s block, this is called sinistral motion. The direction of the strike-slip movement is determined by an observer standing on a block on one side of the fault. In pure strike-slip motion, fault blocks on either side of the fault do not move up or down relative to each other, rather move laterally, side to side. ![]() Strike-slip faults are most commonly associated with transform plate boundaries and are prevalent in transform fracture zones along mid-ocean ridges. Strike-slip faults have side-to-side motion. (CC BY-NC-SA 4.0 International Ron Schott via Flickr \): Ketobe Knob in the San Rafael Swell of Utah displays an example of a thrust fault.
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