Rake>0 means the hanging wall moved up (thrust or reverse fault). Rake=0 means the hanging wall, or the right side of a vertical fault, moved in the strike direction (left lateral motion) Rake = +/-180 means the hanging wall moved in the opposite direction (right lateral motion). Rake - the direction the hanging wall moves during rupture, measured relative to the fault strike (between -180 and 180 decimal degrees). For a vertical, strike slip fault (for which “hanging wall” has no physical meaning) we still call the right-side block the hanging wall to distinguish between right lateral and left lateral motion.ĭip - the angle of the fault in decimal degrees (0 to 90, relative to horizontal). This is important because rake (which gives the slip direction) is defined as the movement of the hanging wall relative to the footwall. This means that the hanging-wall block is always to the right. That is, the fault always dips to the right when moving along the trace in the strike direction (from one point to the next). Strike - the fault-trace direction in decimal degrees (0 to 360, relative to North), defined so that the fault dips to the right side of the trace. 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. Meaning of left-lateral strike-slip fault. The San Andreas Fault is an example of a right lateral fault. Definition of left-lateral strike-slip fault in the dictionary. ![]() ![]() As opposed to the idealized linear movement of a strike-slip fault, the team demonstrated what geologists knew in theory, that shear strain has several stages before final movement along the fault.(adapted from page 106 of Aki & Richards (1980), Quantitative Seismology - Vol 1 ) Our Planet Today on ApWhat is a left lateral strike slip fault Geology If you were to stand on the fault and look along its length, this is a type of strike-slip fault where the left block moves toward you and the right block moves away. strike-slip fault - a fault on which the two blocks slide past one another. left-lateral strike-slip fault - a fault on which the displacement of the far block is to the left when viewed from either. The San Andreas Fault is an example of a right lateral fault. ![]() Normal faults are formed at angles of less than 45°, while thrust faults are formed at angles of more than 45° (Fig. This results in a combination of strike-slip movement and oblique tension. 12.3b) is one in which the block on the opposite side of an observer moves to the left. strike-slip fault - a fault on which the two blocks slide past one another. A sinistral or left-lateral strike-slip fault (Fig. Whether a tensional or compressional stress is created depends on the direction of movement on the fault. When the dip angle is shallow, a reverse fault is often described as a thrust fault. Displaced alluvial fan surveys and dating estimate late Quaternary slip rates of 1.0 mm/yr for the Tacheng fault (Yao et al., 2019 Yu et al., 2021 ), less than 0.5 mm/yr for the Tori fault (Feng, 1997 ) and 0. This is a similar trait we see in many systems on Earth, from rivers finding the easiest path to lower elevations to mammals taking the easiest path from point A to point B.Īs the faults propagate, the team measured how strain is transferred to different parts of the fault, a process that in real life takes millions of years and across many miles. When there is a bend in a strike-slip fault, movement along the fault causes transtension or transpression.This creates a basin where sediments can accumulate (also called the creation of accomodation space.). This fault system commenced with right-lateral faulting and has been inversed to left-lateral slip faulting since the Triassic (Wu et al., 2018). The team found that the faults develop through a "Lazy Earth" hypothesis, whereby the fault propagation takes the easiest path. In one boundary condition, there is a pre-existing fault along the two slabs, in another there is a pre-existing displacement beneath the clay slabs, and in the last example the displacement is in a wider shear zone.Īfter the models were setup, the team moved the two clay slabs in opposite directions in order to measure minute changes as the strike-slip faults developed. After creating two slabs of this kaolin clay, the team setup several boundary conditions on which to test the development of the strike-slip fault. The team made sure the length to depth was scaled appropriately to mimic that on Earth and with the correct viscosity. ![]() Hatem built a miniature model of the Earth's crust using kaolin clay.
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