Simulation for strike-slip fault with step over (pull-apart basin dan push-up ranges)

[DianKusumawati]

Dear Sir,

I am trying to mimic a strike-slip fault with a pull-apart basin system. The system consists of two faults with space in the middle as shown in the figure below. I used fault with static friction (FaultCohesiveDyn) and used two faults, embedded in elastic material. However, the results show a large depression in the cells at the tip of the faults, not the center of the space.

I would like to ask. I there any mistake that I made? and is it possible to make such a modeling (pull apart system) with PyLith? Your guidance is very valuable to us. I look forward to hearing from you.

(I attached some documents supporting the question)

Thank you.

Reference model

My mesh

Displacement result

Cfg and mesh files
cfg.zip
mesh.zip

[baagaard-usgs]

You can use PyLith to model a pull apart basin using geometry like you have. The displacement gradients will be high in and around the pull apart basin, so you should using a finer discretization size in that region. As in any numerical modeling, you should analyze the results carefully to look for discretization errors and refine the mesh accordingly. I recommend plotting the strain field and refine the mesh in the regions where the gradients are very large. You should keep refining the mesh (smaller discretization size, but only in regions that need it) until your results are independent of the discretization size.

[DianKusumawati]

Thank you @baagaard-usgs for the advice. It really helps!