Dynamic Rupture

Computational earthquake dynamics is emerging as a key component in physics-based approaches to strong motion prediction for seismic hazard assessment and in physically constrained inversion approaches to earthquake source imaging from seismological and geodetic observations. Typical applications in both areas require the ability to deal with rupture surfaces of complicated, realistic geometries with high computational efficiency.In our implementation, tetrahedral elements are used which allows for a better fit of the geometrical constraints of the problem, i.e., the fault shape, and for an easy control of the variation of element sizes using smooth refining and coarsening strategies.

Examples of simulation of realistic earthquake sceanrios on geometrically complex faults:

The 1992 Landers scenario

Ground motion of the Landers scenario in terms of absolute particle velocity.

 

 

We simulated the Mw. 7.3 Landers scenario on a branched fault system in a model including geologically constrained fault geometries, topography, the local velocity structure and stress conditions based on geomechanical modeling.

 

 

 

 

The non-linear interaction of the seismic waves with the fault system itself and the spatio-temporally heterogeneous rupture process add further complexity, causing the emergence of multiple rupture fronts.
The resolution in a model consisting in almost 200 mio. elements leads to accelerograms with frequencies up to 10 Hz.

In this high-resolution earthquake model complex rupture
dynamics evolve across the fault system .
Successively, all fault segments of the model rupture spontaneously. Throughout the rupture process we observe fault branching as well as rupture jumps between the discrete fault planes, leaving some segments partially locked.

(for more details, especially from a computational perspective, see:
Heinecke et al. , Petascale High Order Dynamic Rupture Earthquake Simulations on Heterogeneous Supercomputers.  (2014). Gordon Bell Finalist. doi:10.1109/SC.2014.6 )

 

SCEC Benchmark Tests

We are further participating in the SCEC/USGS Dynamic Earthquake Rupture Exercise (http://scecdata.usc.edu/cvws/) where several different numerical approaches and softwares are comparing their results for given dyanamic rupture tests problems. For example for:

  • Rate-and-State friction for a strike-slip fault scenario
  • Test problems with branched faults
  • Simulating plastic material behaviour using the Drucker-Prager yield criterion
  • 60° dipping normal faulting with supershear rupture
     

(for more details see:
Pelties et al. (2014), Verification of an ADER-DG method for complex dynamic rupture problems, doi:10.5194/gmd-7-847-2014. )