Earthquake and fault system dynamics – Putting the pieces together

James H. Dieterich

Published August 15, 2018, SCEC Contribution #8691, 2018 SCEC Annual Meeting Talk on Sun 18:00 (PDF)

In nature earthquakes do not occur as independent events on faults that are isolated in time and space. Rather they occur as emergent phenomena from the system dynamics of geometrically complex fault networks. Earthquake simulations that integrate fault system geometry, evolving stress conditions from interactions among earthquakes, and rate- and state-dependent fault constitutive properties capture well-established system-level characteristics of earthquakes including scaling statistics and Omori-type space-time clustering. In addition, long simulations with the California fault system and Cascadia models point to some relationships that would not be particularly obvious in the short historical record of earthquake observations. Among the relationships of possible significance to short- and long-term forecasts are 1) repeating slip patterns in large earthquakes whose characteristics are tied to the local fault system geometry and loading conditions; 2) the important role of structural complexities in both limiting through-going ruptures and enhancing earthquake clustering; and 3) the dependence of clustering rates on local stress conditions, which affect the probabilities of foreshock/mainshock sequences. Looking ahead, there is much room for further development of fault and earthquake system simulations. Of particular interest is the coupling of fault system simulations and background seismicity occurring off of the major modeled faults. One-way coupling of the background seismicity rates to stress changes from slip on the modeled system faults is doable in the short-term. A proof-of-concept implementation of full coupling appears to be quite promising.

Citation
Dieterich, J. H. (2018, 08). Earthquake and fault system dynamics – Putting the pieces together. Oral Presentation at 2018 SCEC Annual Meeting.

Related Projects & Working Groups
Collaboratory for Interseismic Simulation and Modeling (CISM)