[CIG-SHORT] Kinematic faults vs dynamic faults

[Ruel Jerry]

Hi,
I have what seems like a basic problem, but I can't seem to figure it out. The model that I'm running includes faults at depth that I would like to impose normal stresses on. When I use a kinematic fault where I impose fault opening displacements I get the surface displacements and the stress fields that I would expect. When I try to use dynamic conditions on the same fault and I impose tractions instead of displacement I expect to get similar results. For some reason I get the correct stress on one side of the fault, but the other side seems to have the sign of the stress reversed, and this happens for modes 1,2 and 3. 
For example in mode 1 if I impose slip, if I draw a line through the middle of the fault an look at the XX stress, the stress values from left to right decrease until I reach the fault then they increase symmetrically on the other side back to 0 eventually. If I impose tractions the same line shows stress values from left to right decrease until I reach the fault and then at the interface I get a dislocation, then a positive value with the same magnitude, then the stress decreases.

Is this supposed to be different or am I doing something wrong? It seems like a sign problem somewhere, but I only used one value for initial tractions  and one vale for fault opening.

Thanks,
Ruel Jerry