SCEC Award Number 17167 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title A Novel Hybrid Numerical Scheme for Earthquake Cycle Simulation
Investigator(s)
Name Organization
Ahmed Elbanna University of Illinois at Urbana-Champaign
Other Participants
SCEC Priorities 1d, 3d, 2c SCEC Groups FARM, CS, Seismology
Report Due Date 11/30/2018 Date Report Submitted 11/14/2019
Project Abstract
 Traditionally, bulk methods such as finite difference (FD) and finite elements (FE) as well as Boundary Integral (BI) Method have been used extensively to model spontaneously propagating shear cracks in a variety of engineering and geophysical applications. While FD has a large computational cost as it requires the discretization of the whole volume of interest, it can handle a greater variety of problems in comparison with BI, including bulk nonlinearities and heterogeneities. On the other hand, the BI method eliminates the necessity of simulating the wave propagation in the whole linear elastic medium by leveraging space-time convolutions with the source on the fault surface. The spectral implementation of the BI [Lapusta et al., 2000] is particularly faster and much more computationally efficient than other bulk methods such as FD. However, the spectral boundary integral (SBI) formulation is restricted to linear elastic bulk and planar faults. Here we propose a new method, referred to as the “Hybrid Method”, in which bulk (e.g. FD) and boundary (e.g. SBI) methods are combined to provide exact near field wave truncation while providing high resolution for near fault nonlinearities, heterogeneities, and geometrical complexities. Benefiting from the flexibility of FD and the efficiency of BI, this proposed method will solve a wide range of problems in a computationally efficient way
Intellectual Merit This proposal introduces a novel and computational efficient numerical scheme for modeling dynamic ruptures and qausistatic sliding in complex fault zones. The method enables modeling small scale structural heterogeneities and nonlinearities while maintaining long range stress interaction and removes ambiguity in far-field loading. The method demonstrates superior performance compared to full domain based approaches such as FEM when it comes to modeling single ruptures as well as sequence of earthquakes and aseismic slip.
Broader Impacts 1- Training of two graduate students: Xiao Ma and Mohamed Abdelmeguid.
2- Two journal publications:

Ma, X., Hajarolasvadi, S., Albertini, G., Kammer, D., & Elbanna, A. (2018). A hybrid finite element‐spectral boundary integral approach: Applications to dynamic rupture modeling in unbounded domains. Int J Numer Anal Methods Geomech. 2018;1‐22.
Abdelmeguid, M., Ma, X., & Elbanna, A. E. (2019). A Novel Hybrid Finite Element-Spectral Boundary Integral Scheme for Modeling Earthquake Cycles: Application to Rate and State Faults with Low-Velocity Zones. (Minor Revision – Journal of Geophysical Research Solid Earth) .

3- Participation in SCEC-SEAS community effort.
Exemplary Figure Figure 1