Seismogenic layer

In geophysics and seismology, the seismogenic layer or seismogenic zone covers the range of depths within the crust or lithosphere in which most earthquakes originate.^[1] The thickness is heavily dependent on location. For oceanic crust, the seismogenic layer thickness can be 0 to 40 kilometres (0 to 25 mi), and for continental crust, it ranges from 0 to 25 kilometres (0 to 16 mi).^[2] It is also important to note that at subduction zones, there is one seismogenic layer being pushed on top of another. This can result in extremely deep earthquakes up to 700 kilometres (430 mi) in depth.^[3] The base of this layer represents the downwards change in deformation mechanism from elastic and frictional processes (associated with brittle faulting) to a generally aseismic zone where ductile creep becomes the dominant process. The location of this change in deformation style is sometimes referred to as the brittle–ductile transition zone.^[4]

References

1. Scholz, Christopher (2002). The Mechanics of Earthquakes and Faulting. Cambridge University Press. p. 152. ISBN 9780521655408. Retrieved June 12, 2012.
2. Watts, A.B.; Burov, E.B. (August 2003). "Lithospheric strength and its relationship to the elastic and seismogenic layer thickness". Earth and Planetary Science Letters. 213 (1–2): 113–131. Bibcode:2003E&PSL.213..113W. doi:10.1016/S0012-821X(03)00289-9.
3. Hayes, Gavin; Crone, Tony. "At what depth do earthquakes occur? What is the significance of the depth?". United States Geological Survey.
4. Cole, J.; Hacker, B.; Ratschbacher, L.; Dolan, J.; Seward, G.; Frost, E.; Frank, W. (2007). "Localized ductile shear below the seismogenic zone: Structural analysis of an exhumed strike-slip fault, Austrian Alps" (PDF). Journal of Geophysical Research. 112 (B12): B12304. Bibcode:2007JGRB..11212304C. doi:10.1029/2007JB004975.