Dear Rob et al,
Thanks for your response, which I found very informative because I
have been considering using fault-slip inversions for future
research. I'm keeping this dialogue open to the whole list because I
think it may benefit all of us.
How would you respond to the following two papers?
(1)Sibson & Xie. 1998. Dip range for intracontinental reverse fault
ruptures: Truth not stranger than friction? Bull.Seism.Soc.Am. v88.
1014-1022.
(2) Lisle & Srivastava. 2004. Test of the frictional reactivation
theory for faults and validity of fault-slip analysis. Geology. v32.
569-572.
These papers examine fault orientations and slip directions from both
the rock record and seismological observations. They demonstrate that
the simple frictional slip law that underpins fault-slip inversion
is very predictive for observed fault orientations and slip. The
implication being that the strain recorded by faults in the rock
record can be related to this frictional relation, and that it is not
unreasonable for our purposes to infer stress from the strain. These
results contribute nothing on the scale of a deforming ooid or the
rheology of a volume of cataclasite, but they do suggest that slip on
individual and higher-displacement interlinked faults is well
approximated by simple frictional theory on slipping surfaces. I have
no doubt that we have a lot to learn about the constitutive laws
governing fault slip, cataclastic flow etc but I suspect we already
have a suitable first-order relation which enables us to approximate
useful information. Again I totally agree that it is important to be
explicit in our publications that we are measuring strain and making
some assumptions that enable us to infer stress.
Thanks,
Steve
--
Steven Micklethwaite
Postdoctoral Fellow
Rock Physics,
Research School of Earth Sciences,
Mills Road, ANU
Canberra, ACT 0200
T: +61 2 61255169
F: +61 2 61258253
http://rses.anu.edu.au/petrophysics/Staff/StevenMHome.html
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