Problem with static friction fault

Hello, I am using pylith v2.2 to model the interseismic period of a subduction zone with a 3d mesh. I have a dynamic fault with static friction in the seismogenic zone (10-70km deep). My problem are the deeper nodes, they’re always locked and doesn’t creep, even if I set the friction coefficient to 0 or run the model for many years. Is there any way to free these nodes to slide?

This has an effect in the shallower nodes and generates a significant amount of deformation, I show this in a map of the fault coupling with friction coefficient 0 in all nodes.

The vectors are the synthetic GPS velocities. I’m guessing this is due to the edge nodes of the fault, but I don’t know how to handle this background deformation if I can’t set the edge nodes to slide.

I would start by double checking all of the *_info files in the output to make sure the spatial variations you think you are creating are actually applied. I might be able to apply more guidance if you supply a sketch or diagram of the boundary value problem you are trying to solve that shows all of your BCs and fault conditions.

I apply two kinematic fault that creep and a dynamic fault with static friction, this is a 2d diagram.
I have dirichlet BC in the north, south, east, west and base surfaces, except in the nodes of the slab. I think the problem is in the edge set nodes between the dynamic fault and the kinematic fault.
I checked the h5 files and the creep in the both kinematic faults, and it’s ok, i don’t know how to check in the output file if the friction coefficient that i impose in the spatialdb file were actually applied, but in the spatialdb file is right.

Sorry, this got buried in my inbox.

You are correct that the problem is the edge between the dynamic and kinematic faults. These nodes will be pinned (zero slip). We recognize this problem but don’t yet have a resolution. The workaround is to make the top of the slap all dynamic and set the fault constitutive parameters so that you get the desired behavior.