El Arrayán Fault ( es, Falla El Arrayán) is a

geological fault In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tecto ...

, located inmediataly north of the city of

Santiago Santiago (, ; ), also known as Santiago de Chile, is the capital and largest city of Chile as well as one of the largest cities in the Americas. It is the center of Chile's most densely populated region, the Santiago Metropolitan Region, who ...

in Chile. The fault runs in northwest-southeast direction. Likely, the fault was last active sometime in the Quaternary period (last 2.5 million years). It is chiefly a

strike-slip fault In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tecton ...

Fault scarp A fault scarp is a small step or offset on the ground surface where one side of a fault has moved vertically with respect to the other. It is the topographic expression of faulting attributed to the displacement of the land surface by movement al ...

sag pond A sag pond is a body of fresh water collected in the lowest parts of a depression formed between two sides of an active strike-slip, transtensional or normal fault zone. Formation A sag pond is formed along a strike-slip fault, which may creat ...

s, mountain saddles and stream deflection are some of the surface features of El Arrayán Fault. The fault is estimated to be able to produce 6.4 Mw-strong earthquakes which make it a significant risk factor for the northernmost neighbourhoods of Santiago.

References

Geology of Santiago Metropolitan Region Seismic faults of Chile {{Chile-geo-stub