Are impact-generated lower-crustal faults observable?
Theoretical calculations coupled with present-day knowledge of the dynamic tensile behaviour of
rock indicate that the propagating shock wave, and accompanying rarefaction wave, from a large
meteoritic impact event may fracture the crust down to the Moho. Diapiric action by trapped upper
mantle fluids could lead to annealing of these sub-vertical faults by material of high carbon content.
Are these faults observable on the surface using geophysical methods? One possible means proposed is
to try to monitor current flowing down them by an appropriate natural-source electromagnetic experiment.
An example is discussed for which such current flow may be occurring.
Earth and Planetary Science Letters, 85, 248-252, 1987.
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Alan G Jones / 10 June 2004 /