![]() If the rock mass on a sloping fault moves downward, the it is normally called reverse if the rock above the fault moves upward. The character of the movement (offset) along the fracture plane determines what kind of dip-slip fault it is. There are three types of dip-slip faults: normal, reverse, and thrust. The side where you can hang your feet without touching the floor is the hanging wall. It is simply described here – if a fault plane is exposed well enough to see that it is inclined, the side on which you can stand is called the foot wall. The relative motion of faults (one side to the other) is described in terms of relationship of a hanging wall and foot wall.Ī foot wall is a block under a fault with a sloping fault plane.Ī hanging wall is a block ( rocks) at the top of a sloping fault plane. Faults are separated, bifurcated, converge, or move away from distances, sometimes creating complex fracture systems. It can be small and large complex interconnection fault systems and can replace one type of fault in one location with another type in another. ![]() ![]() Types of faults include strike-slip faults, normal faults, reverse faults, thrust faults, and oblique-slip faults. If this movement may occur rapidly, it can be causes earthquike or slowly, in the form of creep. Strike-slip fault - a fault on which the two blocks slide past one another. The San Andreas Fault is an example of a right lateral fault.Ī left-lateral strike-slip fault is one on which the displacement of the far block is to the left when viewed from either side.Ī right-lateral strike-slip fault is one on which the displacement of the far block is to the right when viewed from either side.Fault is a fracture or crack where two rock blocks slide past one to another. Reverse (thrust) fault - a dip-slip fault in which the upper block, above the fault plane, moves up and over the lower block. This type of faulting is common in areas of compression, such as regions where one plate is being subducted under another as in Japan. When the dip angle is shallow, a reverse fault is often described as a thrust fault. Normal fault - a dip-slip fault in which the block above the fault has moved downward relative to the block below. This type of faulting occurs in response to extension and is often observed in the Western United States Basin and Range Province and along oceanic ridge systems. ![]() The following definitions are adapted from The Earth by Press and Siever. A fault is a fracture or zone of fractures between two blocks of rock. Faults allow the blocks to move relative to each other. This movement may occur rapidly, in the form of an earthquake - or may occur slowly, in the form of creep. Faults may range in length from a few millimeters to thousands of kilometers. Most faults produce repeated displacements over geologic time. During an earthquake, the rock on one side of the fault suddenly slips with respect to the other. The fault surface can be horizontal or vertical or some arbitrary angle in between.Įarth scientists use the angle of the fault with respect to the surface (known as the dip) and the direction of slip along the fault to classify faults. Faults which move along the direction of the dip plane are dip-slip faults and described as either normal or reverse (thrust), depending on their motion. Faults which move horizontally are known as strike-slip faults and are classified as either right-lateral or left-lateral. Faults which show both dip-slip and strike-slip motion are known as oblique-slip faults. ![]()
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