1. 16/9/2011UCERF3 / EQ Simulators Workshop ViscoSim Fred Pollitz USGS, Menlo Park

2. 26/9/2011UCERF3 / EQ Simulators Workshop Representation of Fault Friction Static frictional stress Dynamic frictional stress Arrest stress Dynamic overshoot parameter: Stress reduction parameter:  =  s -  a D =  s -  a )/(  s -  d )

3. 36/9/2011UCERF3 / EQ Simulators Workshop Representation of Fault Friction

4. 46/9/2011UCERF3 / EQ Simulators Workshop Representation of Viscoelasticity    Pa s  3 x    Pa s

5. 56/9/2011UCERF3 / EQ Simulators Workshop

6. 66/9/2011UCERF3 / EQ Simulators Workshop

7. 76/9/2011UCERF3 / EQ Simulators Workshop

8. 86/9/2011UCERF3 / EQ Simulators Workshop

9. 96/9/2011UCERF3 / EQ Simulators Workshop

10. 106/9/2011UCERF3 / EQ Simulators Workshop

11. 116/9/2011UCERF3 / EQ Simulators Workshop

12. 126/9/2011UCERF3 / EQ Simulators Workshop

13. 136/9/2011UCERF3 / EQ Simulators Workshop Approximations to Elastodynamics Representation of inertia –None Representation of rupture propagation –Cascade model

14. 146/9/2011UCERF3 / EQ Simulators Workshop Fault Interaction

15. 156/9/2011UCERF3 / EQ Simulators Workshop # Viscoelastic Greens functions = x 3721 [map points] X 16 [source depths] X 16 [obs. depths] x 11 [sample times] x 6 [stress tensor components] = 6 x 10 7

16. 166/9/2011UCERF3 / EQ Simulators Workshop Twenty consecutive M>6.7 ruptures M6.9

17. 176/9/2011UCERF3 / EQ Simulators Workshop M7.2

18. 186/9/2011UCERF3 / EQ Simulators Workshop M7.0

19. 196/9/2011UCERF3 / EQ Simulators Workshop M7.6

20. 206/9/2011UCERF3 / EQ Simulators Workshop M6.7

21. 216/9/2011UCERF3 / EQ Simulators Workshop M7.5

22. 226/9/2011UCERF3 / EQ Simulators Workshop M7.6

23. 236/9/2011UCERF3 / EQ Simulators Workshop M7.2

24. 246/9/2011UCERF3 / EQ Simulators Workshop M6.7

25. 256/9/2011UCERF3 / EQ Simulators Workshop M6.7

26. 266/9/2011UCERF3 / EQ Simulators Workshop M7.7

27. 276/9/2011UCERF3 / EQ Simulators Workshop M7.3

28. 286/9/2011UCERF3 / EQ Simulators Workshop M7.5

29. 296/9/2011UCERF3 / EQ Simulators Workshop M7.3

30. 306/9/2011UCERF3 / EQ Simulators Workshop M7.3

31. 316/9/2011UCERF3 / EQ Simulators Workshop M7.2

32. 326/9/2011UCERF3 / EQ Simulators Workshop M6.7

33. 336/9/2011UCERF3 / EQ Simulators Workshop M7.2

34. 346/9/2011UCERF3 / EQ Simulators Workshop M7.3

35. 356/9/2011UCERF3 / EQ Simulators Workshop M7.5

36. 366/9/2011UCERF3 / EQ Simulators Workshop Simulator parameters Dynamic overshoot parameter: Stress reduction parameter:  =  s -  a D =  s -  a )/(  s -  d ) Shape of slip-weakening curve Mantle viscosity  m

37. 376/9/2011UCERF3 / EQ Simulators Workshop Results with ViscoSim Fault system behavior is sensitive to simple parameters Simulations capture Gutenberg-Richter and characteristic-earthquake behavior Characteristic magnitude and mean recurrence interval may exhibit a systematic dependence on mantle viscosity