1. Viscoelastic-coupling model for the earthquake cycle driven from below
J.C. Savage
U.S. Geological Survey, Menlo Park, CA
Ge 277, Thomas ADER, January 27, 2011

2. Representation of the Bourne’s Model.
Bourne et al. [1998]
“ The intersismic velocity profile across a transform fault at the surface would be a replica of a similar profile at the top of the upper mantle. ”
Savage (2000)
Savage [2000]
“ For a linear system, (…) interseismic deformation along such a profile (…) is determined by the parameters H and t0 and does not depend at all upon the velocity profile at the top of the upper mantle. ”
T, recurrence time
of earthquakes
Representation of the Bourne’s Model.
relaxation time
Savage (2000)

3. Viscoelastic-Coupling model driven by the Schizosphere stress guide
Surface velocity
time evolution

4. Viscoelastic-Coupling model driven by the Schizosphere stress guide
Depth velocity
time evolution

5. Viscoelastic-Coupling model driven by the Schizosphere stress guide
Stress plastosphere -> schizosphere
time evolution
> 0

6. Viscoelastic-Coupling model driven by the Schizosphere stress guide
Dependence with

7. Viscoelastic-Coupling model driven from below
Same problem as before with boundary condition locked at depth +
driving solution that provides driving force.
Boundary condition locked at the top

8. Viscoelastic-Coupling model driven from below
Surface velocity
Same as before, but with boundary condition at y = H+D.

9. Viscoelastic-Coupling model driven from below
Stress at the bottom of the upper crust

10. Viscoelastic-Coupling model driven from below
Driving solution:
Velocity in the lower crust

11. Viscoelastic-Coupling model driven from below
Driving solution:
Stress at the bottom of the upper crust

12. Conclusion
Surface displacement doesn’t depend on the displacement of the upper mantle
Surface displacement depends on the parameters H (thickness of the schizosphere) and t0
Model valid only where the Earth model is linear (superposition of solutions).