Error with prescribed EQ nucleation time

Hi Pylith team,

I am running a very simple reference model on a toy mesh. I prescribe an event at t=100yrs for a viscoelastic crust with Maxwell time 70 years. The simulation runs for 700 years to allow for substantial relaxation to happen after the event. Instead of relaxing after the event, a new event nucleates after a given time (see screenshot of paraview average displacement file). This event is never prescribed in the .cfg file (see attached). Every time step in the output file is 70 years.

Any suggestions of what’s going on are welcome.

Thank you,


viscoelasticref.cfg (6.9 KB) pylithapp.cfg (2.8 KB)

I don’t understand your displacement plot. I would expect to see nothing happen from 0 to 100 years, and then see the displacement associated with the earthquake at 100 years, followed by postsesimic relaxation.

With a Maxwell time of 70 years, you will need time steps on the order of 7 years or less to resolve the postseismic relaxation. There is no reason to use adaptive time stepping as the stable time step is fixed at 1/10 or less of the Maxwell time, so you can simply use 7 years or less.

The time of slip is specified by the origin time plus the time in the spatial distribution of the slip time (as given in your spatialdb/sliptime.spatialdb). If you want slip at 100 years, then your sliptime.spatialdb can be zero because you have given an origin time of 100 years.

Tip: Using HDF5 output makes it easy to load your data into Matlab or Python to plot time histories, etc rather than relying on ParaView.