# PyLith **URL:** https://community.geodynamics.org/c/pylith/29.md [Latest](https://community.geodynamics.org/latest.md) · [Categories](https://community.geodynamics.org/categories.md) · [Tags](https://community.geodynamics.org/tags.md) --- ## [Information to provide when troubleshooting simulations](https://community.geodynamics.org/t/information-to-provide-when-troubleshooting-simulations/2718)
**Author:** [@baagaard](https://community.geodynamics.org/u/baagaard)\ **Replies:** 0\ **Last updated:** [December 8, 2022, 6:55pm UTC](https://community.geodynamics.org/t/information-to-provide-when-troubleshooting-simulations/2718 "2022-12-08T18:55:25Z")
When submitting a question about running a simulation, be sure to include the info: Indicate which PyLith version you are using along with whether you are using the binary, container, or building from source. Describe … --- ## [About the PyLith category](https://community.geodynamics.org/t/about-the-pylith-category/183)
**Author:** [@ljhwang](https://community.geodynamics.org/u/ljhwang)\ **Replies:** 0
Discuss PyLith. Get help with installation. Ask questions about running the code. Start a discussion on new and/or existing features. --- ## [How to calculate Green's function in fault cell](https://community.geodynamics.org/t/how-to-calculate-greens-function-in-fault-cell/4625)
**Author:** [@egg\_chen](https://community.geodynamics.org/u/egg_chen)\ **Replies:** 5\ **Last updated:** [September 17, 2026, 3:54pm UTC](https://community.geodynamics.org/t/how-to-calculate-greens-function-in-fault-cell/4625 "2026-09-17T15:54:30Z")
Hello everyone! I am currently calculating Green’s functions, and I want to compute the surface displacement response to unit slip on a single fault cell. The PyLith v5 manual states: A basis order of 0 will impose un… --- ## [PyLith v5.0.2 released](https://community.geodynamics.org/t/pylith-v5-0-2-released/4609)
**Author:** [@baagaard](https://community.geodynamics.org/u/baagaard)\ **Replies:** 0\ **Last updated:** [August 16, 2026, 2:47pm UTC](https://community.geodynamics.org/t/pylith-v5-0-2-released/4609 "2026-08-16T14:47:07Z")
PyLith v5.0.2 now available I am pleased to announce the release of PyLith 5.0.2, a finite-element code designed to solve dynamic elastic problems and quasi-static viscoelastic problems in tectonic deformation. You can … --- ## [Why is mesh initialization still very slow after converting my Cubit mesh to HDF5?](https://community.geodynamics.org/t/why-is-mesh-initialization-still-very-slow-after-converting-my-cubit-mesh-to-hdf5/4597)
**Author:** [@Hsiaolun](https://community.geodynamics.org/u/Hsiaolun)\ **Replies:** 6\ **Last updated:** [August 7, 2026, 1:14am UTC](https://community.geodynamics.org/t/why-is-mesh-initialization-still-very-slow-after-converting-my-cubit-mesh-to-hdf5/4597 "2026-08-07T01:14:15Z")
Hi there, I am running a large 3D model with PyLith 5.0.1. Because reading a Cubit Exodus mesh is serial, I converted the mesh to PETSc HDF5 so that PyLith could read it in parallel. I expected the HDF5 workflow to make… --- ## [3D viscoelastic coseismic slip fails to be applied by linear interpolation](https://community.geodynamics.org/t/3d-viscoelastic-coseismic-slip-fails-to-be-applied-by-linear-interpolation/4578)
**Author:** [@Qingjun](https://community.geodynamics.org/u/Qingjun)\ **Replies:** 10\ **Last updated:** [August 5, 2026, 7:49pm UTC](https://community.geodynamics.org/t/3d-viscoelastic-coseismic-slip-fails-to-be-applied-by-linear-interpolation/4578 "2026-08-05T19:49:39Z")
Hi there, I met a problem when trying to apply the coseismic slip using linear interpolation, as shown below, in Pylith 5 and also Pylith 4.2 for 3D viscoelastic case, using displacement.basis\_order = 2, lagrange\_multip… --- ## [3D viscoelastic problem with uniform reverse slip within a triangle patch, does not converge in Pylith 4.2](https://community.geodynamics.org/t/3d-viscoelastic-problem-with-uniform-reverse-slip-within-a-triangle-patch-does-not-converge-in-pylith-4-2/4592)
**Author:** [@Qingjun](https://community.geodynamics.org/u/Qingjun)\ **Replies:** 2\ **Last updated:** [August 1, 2026, 1:02am UTC](https://community.geodynamics.org/t/3d-viscoelastic-problem-with-uniform-reverse-slip-within-a-triangle-patch-does-not-converge-in-pylith-4-2/4592 "2026-08-01T01:02:23Z")
Hi there, I recently met a new problem when trying to calculate GF for 3D viscoelastic problem. I use .spatialdb file to assign a uniform reverse slip on a triangle patch (and slip outside of it is zero). The material i… --- ## [Mesh refinement sensitivity in quasi-static coseismic slip traction calculations](https://community.geodynamics.org/t/mesh-refinement-sensitivity-in-quasi-static-coseismic-slip-traction-calculations/4574)
**Author:** [@yangxiao](https://community.geodynamics.org/u/yangxiao)\ **Replies:** 11\ **Last updated:** [July 14, 2026, 1:49pm UTC](https://community.geodynamics.org/t/mesh-refinement-sensitivity-in-quasi-static-coseismic-slip-traction-calculations/4574 "2026-07-14T13:49:19Z")
Dear Baagaard , I am running quasi-static simulations of coseismic slip-induced stress changes (traction) on a planar fault using PyLith 2.2.2. I have encountered a puzzling issue: the computed traction distribution cha… --- ## [Deformation sensitivity to mesh resolution](https://community.geodynamics.org/t/deformation-sensitivity-to-mesh-resolution/4579)
**Author:** [@apear](https://community.geodynamics.org/u/apear)\ **Replies:** 1\ **Last updated:** [July 10, 2026, 2:26am UTC](https://community.geodynamics.org/t/deformation-sensitivity-to-mesh-resolution/4579 "2026-07-10T02:26:35Z")
I am trying to figure out why the sensitivity of the deformation to the mesh resolution doesn’t seem to be converging. Trying to run the simplest version of this issue: I’m running the subduction-3d example gmsh mesh, b… --- ## [Run a simple 3D strike slip model using Pylith 5, met conversion problem](https://community.geodynamics.org/t/run-a-simple-3d-strike-slip-model-using-pylith-5-met-conversion-problem/4567)
**Author:** [@Qingjun](https://community.geodynamics.org/u/Qingjun)\ **Replies:** 3\ **Last updated:** [June 24, 2026, 1:33pm UTC](https://community.geodynamics.org/t/run-a-simple-3d-strike-slip-model-using-pylith-5-met-conversion-problem/4567 "2026-06-24T13:33:56Z")
Hi there, I construct a strike slip 3D viscoelastic model (with elastic crust and viscoelastic model, relaxation time about 11 yr), with 30km thick crust and applied a uniform slip on the fault interface (only in the cr… --- ## [Modeling Multiple Faults Based on Cubit](https://community.geodynamics.org/t/modeling-multiple-faults-based-on-cubit/4565)
**Author:** [@Dyrussss](https://community.geodynamics.org/u/Dyrussss)\ **Replies:** 2\ **Last updated:** [June 19, 2026, 9:34am UTC](https://community.geodynamics.org/t/modeling-multiple-faults-based-on-cubit/4565 "2026-06-19T09:34:42Z")
Dear PyLith team, I want to simulate post-seismic deformation, and the fault geometry is shown in the figure. My PyLith version is 2.2.2. Based on my current understanding, the fault planes should be internal interfaces… --- ## [SimpleDB boundary condition for varied displacement rate](https://community.geodynamics.org/t/simpledb-boundary-condition-for-varied-displacement-rate/3792)
**Author:** [@dian.k](https://community.geodynamics.org/u/dian.k)\ **Replies:** 19\ **Last updated:** [June 8, 2026, 3:51pm UTC](https://community.geodynamics.org/t/simpledb-boundary-condition-for-varied-displacement-rate/3792 "2026-06-08T15:51:55Z")
Dear Pylith developer, I would like to create 3D modeling of inter-seismic fault deformation with boundary condition of displacement rate like in this figure below. The displacement rate (mm/ year) is applied and varied… --- ## [PyLith v5.0.1 released](https://community.geodynamics.org/t/pylith-v5-0-1-released/4559)
**Author:** [@baagaard](https://community.geodynamics.org/u/baagaard)\ **Replies:** 0\ **Last updated:** [June 7, 2026, 2:25am UTC](https://community.geodynamics.org/t/pylith-v5-0-1-released/4559 "2026-06-07T02:25:56Z")
PyLith v5.0.1 release I am pleased to announce the release of PyLith 5.0.1, a finite-element code designed to solve dynamic elastic problems and quasi-static viscoelastic problems in tectonic deformation. You can downlo… --- ## [PETSC ERROR in coupling Poroelasticity and coseismic processes](https://community.geodynamics.org/t/petsc-error-in-coupling-poroelasticity-and-coseismic-processes/4542)
**Author:** [@HurleyKane](https://community.geodynamics.org/u/HurleyKane)\ **Replies:** 3\ **Last updated:** [June 4, 2026, 11:53am UTC](https://community.geodynamics.org/t/petsc-error-in-coupling-poroelasticity-and-coseismic-processes/4542 "2026-06-04T11:53:41Z")
Dear Aagaard, I encountered some issues while using PyLith 4.2.1 to simulate coseismic poroelastic changes and would like to seek your advice. In my model, I defined a fault with dimensions of 100 km × 20 km withi… --- ## [Taking Green's Functions from Step 7 a and b (Subduction 3D) to use in TDefnode](https://community.geodynamics.org/t/taking-greens-functions-from-step-7-a-and-b-subduction-3d-to-use-in-tdefnode/4520)
**Author:** [@kylehussey504](https://community.geodynamics.org/u/kylehussey504)\ **Replies:** 2\ **Last updated:** [April 22, 2026, 9:32pm UTC](https://community.geodynamics.org/t/taking-greens-functions-from-step-7-a-and-b-subduction-3d-to-use-in-tdefnode/4520 "2026-04-22T21:32:38Z")
Hello All, My name is Kyle Hussey, a current undergraduate student at The College of New Jersey, and I am doing research under Dr. Shannon Graham. We would like to use the Green’s Functions that are created when running… --- ## [Parameter settings for improving PyLith performance](https://community.geodynamics.org/t/parameter-settings-for-improving-pylith-performance/4507)
**Author:** [@baagaard](https://community.geodynamics.org/u/baagaard)\ **Replies:** 0\ **Last updated:** [April 7, 2026, 2:16pm UTC](https://community.geodynamics.org/t/parameter-settings-for-improving-pylith-performance/4507 "2026-04-07T14:16:08Z")
Several performance improvements are coming in PyLith version 5 (anticipated release in early June 2026). Two of these improvements only involve updating PETSc options, so they can be used in PyLith version 4.1 and later… --- ## [Questions Regarding the Computation of Green's Functions in PyLith？](https://community.geodynamics.org/t/questions-regarding-the-computation-of-greens-functions-in-pylith/4101)
**Author:** [@yangxiao](https://community.geodynamics.org/u/yangxiao)\ **Replies:** 28\ **Last updated:** [April 7, 2026, 2:02pm UTC](https://community.geodynamics.org/t/questions-regarding-the-computation-of-greens-functions-in-pylith/4101 "2026-04-07T14:02:30Z")
Sir, I am using the subduction3d example in PyLith 2.2.2 to perform elastic and viscoelastic simulations in step06. Then, I use step07a and 07b to compute the Green’s functions. However, I encountered a problem: although… --- ## [Question About Boundary Conditions for Compressional Thickening and Airy Compensation in PyLith](https://community.geodynamics.org/t/question-about-boundary-conditions-for-compressional-thickening-and-airy-compensation-in-pylith/4503)
**Author:** [@Xiaojie](https://community.geodynamics.org/u/Xiaojie)\ **Replies:** 4\ **Last updated:** [April 1, 2026, 3:34pm UTC](https://community.geodynamics.org/t/question-about-boundary-conditions-for-compressional-thickening-and-airy-compensation-in-pylith/4503 "2026-04-01T15:34:13Z")
Dear everyone, I am new to PyLith (4.2.1) and have been testing some simple examples related to the problems I hope to study, starting with box-3d. The issue I am running into is the following. If I set up a compressio… --- ## [Cubit mesh for crustal-strikeslip-3d example](https://community.geodynamics.org/t/cubit-mesh-for-crustal-strikeslip-3d-example/4502)
**Author:** [@apear](https://community.geodynamics.org/u/apear)\ **Replies:** 1\ **Last updated:** [March 31, 2026, 9:19pm UTC](https://community.geodynamics.org/t/cubit-mesh-for-crustal-strikeslip-3d-example/4502 "2026-03-31T21:19:12Z")
I’m attempting to run the crustal-strikeslip-3d example on pylith 4.2.1 using the binary. I can run the gmsh version without problems, but I get an error saying there is an inverted cell in the mesh when I run the CUBIT … --- ## [How to control the fault normal direction?](https://community.geodynamics.org/t/how-to-control-the-fault-normal-direction/4487)
**Author:** [@Hsiaolun](https://community.geodynamics.org/u/Hsiaolun)\ **Replies:** 2\ **Last updated:** [March 13, 2026, 2:52pm UTC](https://community.geodynamics.org/t/how-to-control-the-fault-normal-direction/4487 "2026-03-13T14:52:25Z")
Hi everyone, I am building 3D subduction zone models using Cubit and PyLith. I’ve run into a recurring issue regarding the orientation of the fault local coordinate system, specifically the normal\_dir. In some models, th… --- ## [Coupling model with poroelastic and viscoelastic](https://community.geodynamics.org/t/coupling-model-with-poroelastic-and-viscoelastic/4454)
**Author:** [@sheyu921](https://community.geodynamics.org/u/sheyu921)\ **Replies:** 2\ **Last updated:** [February 8, 2026, 4:01am UTC](https://community.geodynamics.org/t/coupling-model-with-poroelastic-and-viscoelastic/4454 "2026-02-08T04:01:49Z")
Dear all, I would like to use PyLith to simulate earthquake deformation with a coupled model consisting of a poroelastic crust and a viscoelastic mantle. I have already worked through the poroelastic example (2D Outer-R… --- ## [A fault crossing two materials in 3-D](https://community.geodynamics.org/t/a-fault-crossing-two-materials-in-3-d/4442)
**Author:** [@yifany](https://community.geodynamics.org/u/yifany)\ **Replies:** 2\ **Last updated:** [January 26, 2026, 8:08am UTC](https://community.geodynamics.org/t/a-fault-crossing-two-materials-in-3-d/4442 "2026-01-26T08:08:00Z")
Dear PyLith developing team, Thanks for your continuous effort. I am building a toy model of a fault embedded in a box cutting two layers of materials. The setup looks like this: I took care to mark the fault edges… --- ## [Regarding the issue of linear interpolation in spatial databases](https://community.geodynamics.org/t/regarding-the-issue-of-linear-interpolation-in-spatial-databases/4387)
**Author:** [@xxx](https://community.geodynamics.org/u/xxx)\ **Replies:** 1\ **Last updated:** [December 16, 2025, 3:03pm UTC](https://community.geodynamics.org/t/regarding-the-issue-of-linear-interpolation-in-spatial-databases/4387 "2025-12-16T15:03:50Z")
Dear everyone I want to calculate the shear stress variation on another fault (Fault 1) through the coseismic slip of one fault (Fault 2 and Fault 3) on the intersecting fault At the very beginning, I set up friction o… --- ## [The error in simulation of timehistory](https://community.geodynamics.org/t/the-error-in-simulation-of-timehistory/4371)
**Author:** [@HangWu](https://community.geodynamics.org/u/HangWu)\ **Replies:** 1\ **Last updated:** [November 28, 2025, 5:04pm UTC](https://community.geodynamics.org/t/the-error-in-simulation-of-timehistory/4371 "2025-11-28T17:04:28Z")
multiSlip.cfg (7.2 KB) Time.txt (913 Bytes) MultiSlip.txt (873 Bytes) pylithapp.cfg (4.4 KB) Hi there, Recently, I wanted to apply multiple coseismic slip events within a single simulation period, so I used the Time… --- ## [Question about Dirichlet Boundary Conditions](https://community.geodynamics.org/t/question-about-dirichlet-boundary-conditions/314)
**Author:** [@tuxiang](https://community.geodynamics.org/u/tuxiang)\ **Replies:** 4\ **Last updated:** [November 20, 2025, 2:42am UTC](https://community.geodynamics.org/t/question-about-dirichlet-boundary-conditions/314 "2025-11-20T02:42:33Z")
Hello, everyone I am very confused about Dirichlet Boundary Conditions. Such as the example given by the manual: \[pylithapp.problem\] bc = \[mybc\] \[pylithapp.problem.bc.mybc\] label = group A bc\_dof = \[2\] ; fixed dis… --- ## [Nonlinear solve did not converge with comments "Line search: Cubic step no good, shrinking lambda"](https://community.geodynamics.org/t/nonlinear-solve-did-not-converge-with-comments-line-search-cubic-step-no-good-shrinking-lambda/4316)
**Author:** [@dian.k](https://community.geodynamics.org/u/dian.k)\ **Replies:** 2\ **Last updated:** [November 20, 2025, 2:32am UTC](https://community.geodynamics.org/t/nonlinear-solve-did-not-converge-with-comments-line-search-cubic-step-no-good-shrinking-lambda/4316 "2025-11-20T02:32:09Z")
Dear Sir, I use Pylith 2.2.1 to model interseismic deformation (with displacement rate applied on the boundaries), with several faults embedded in the model. At first when I ran the model with six faults, the model ran… --- ## [PyLith-2.2.2: Could not find slip rate](https://community.geodynamics.org/t/pylith-2-2-2-could-not-find-slip-rate/4359)
**Author:** [@Dyrussss](https://community.geodynamics.org/u/Dyrussss)\ **Replies:** 2\ **Last updated:** [November 14, 2025, 1:30am UTC](https://community.geodynamics.org/t/pylith-2-2-2-could-not-find-slip-rate/4359 "2025-11-14T01:30:56Z")
Dear PyLith team: I’m using backslip model to simulate interseismic deformation. I first verified the case with uniform slip-rate on the fault. However, when I attempted to perform a checkerboard test, the code failed w… --- ## [Strange fault direction](https://community.geodynamics.org/t/strange-fault-direction/4349)
**Author:** [@Hsiaolun](https://community.geodynamics.org/u/Hsiaolun)\ **Replies:** 2\ **Last updated:** [November 3, 2025, 12:10pm UTC](https://community.geodynamics.org/t/strange-fault-direction/4349 "2025-11-03T12:10:52Z")
Hello everyone, I am working with a PyLith simulation that involves a complex, non-planar (curved) fault. I’m currently trying to visualize the fault direction in ParaView. However, I get a result that seems non-intuitiv… --- ## [How to model the rate of interseismic deformation of the surface in 3D fault zones?](https://community.geodynamics.org/t/how-to-model-the-rate-of-interseismic-deformation-of-the-surface-in-3d-fault-zones/3303)
**Author:** [@zhaxj](https://community.geodynamics.org/u/zhaxj)\ **Replies:** 9\ **Last updated:** [September 26, 2025, 6:35am UTC](https://community.geodynamics.org/t/how-to-model-the-rate-of-interseismic-deformation-of-the-surface-in-3d-fault-zones/3303 "2025-09-26T06:35:55Z")
Hi, The output of the Pylith example is almost displacement. I would like to build a 3D fault model to simulate the rate of interseismic deformation at the surface. I have tried several times without success. Can you pl… --- ## [Reference stresses for thinned crust](https://community.geodynamics.org/t/reference-stresses-for-thinned-crust/4300)
**Author:** [@earzabala](https://community.geodynamics.org/u/earzabala)\ **Replies:** 4\ **Last updated:** [September 23, 2025, 8:09pm UTC](https://community.geodynamics.org/t/reference-stresses-for-thinned-crust/4300 "2025-09-23T20:09:19Z")
Hello! Quick question, when running a static simulation with gravitational body forces and reference stresses on a 2D domain that looks like this: Would I set up the reference stresses from 0 to 40 km in the crust a… [Next page](https://community.geodynamics.org/c/pylith/29.md?page=1)