A New Friction Law for Seismicity Modeling
Abstract
Fracture friction is important in a variety of fields, including shear stimulation and induced seismicity in Enhanced Geothermal Systems. The way that friction is treated in a stimulation model has a first order effect on the behavior of the system. There is not a universally accepted method for modeling friction. A variety of approaches have been used, each with relative strengths and weaknesses. A constant friction approach is unable to model seismicity. Kinematic models can lead to results that are not in force equilibrium. Methods imposing an instantaneous drop in frictional strength or an instantaneous displacement suffer from a problem of causality and lack the ability to model aseismic slip. Rate and state friction is well established physically, but is very computationally intensive. Velocity weakening friction cannot model aseismic slip, leads to chaotic results, and does not provide a mechanism for friction restrengthening. We propose a friction treatment that is roughly based on these other approaches, but combines the best aspects of each. Our method of handling friction can model either seismic or aseismic slip, does not impose instantaneous changes in physical parameters, ensures force equilibrium, can be used with explicit time stepping, and leads to reasonable accuracy for even a coarse spatial discretization. Our friction treatment is also flexible enough to be adapted easily to suit particular applications.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.H31L..08M
- Keywords:
-
- 1822 HYDROLOGY / Geomechanics;
- 7209 SEISMOLOGY / Earthquake dynamics;
- 7223 SEISMOLOGY / Earthquake interaction;
- forecasting;
- and prediction