[CIG-MC] CitComCU damage rheology

[Norm Sleep]

One can use damage rheology to do nonlinear rheology with linear 
code.That is, the steady state with damage and healing is power law 
but each flow step is linear.  One can advect damage.  One can like 
Tackley do faults with damage rheology that is steady state strain 
rate strengthening at low strain rates but strain rate weakening 
above a yield stress.  This can be generalized to damage tensors but 
is real mess. I may try rate and state fluid in shear zone at some 
stage but it does not look easy.

As anyone tried any of these?

FYI on bottom permeable boundary condition.  One must make vertical 
derive of viscosity zero at the boundary.  It also helps to turn off 
conduction in a way the conserves energy at and just above the 
boundary.  I presume that these carry through from finite difference.


thanks


Norm