Exploring the dynamics of crustal fault system models with micro-scale and CA simulations

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Exploring the dynamics of crustal fault system
models with micro-scale and CA simulations

• Peter Mora, David Place,
• Dion Weatherley, Steffen Abe
• Yucang Wang

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To predict or not to predict, that is the
question!
Observations such as accelerating seismic energy
release high Load-Unload response
ratio preceding large earthquakes provide
encouragement, understanding of the physics is
required.
From, Yin, Mora, Peng, Wang and Weatherley, 2002,
PAGEOPH, Vol. 159, No. 10
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Critical scaling region size
Critical region scaling with magnitude suggest a
physical mechanism rather than statistical
fluctuations are the origin of such observations.
7.8
7.0
6.5
5.7
5.0
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No eq cycle prediction impossible

• SOC behaviour

Eq cycle exists prediction possible
CP behaviour Power law time-to-failure Evolution
of statistics
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Overview

• Why use particle and CA simulations.
• What was learned from particle simulations.
• What has been learned from CA simulations.
• What kind of complex system is the crust?
• Conclusion

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Why use particle and CA simulations

• CA simulations
• Pro Fast can explore
• overall system dynamics
• Con Simplifications may
• affect behaviour

• Particle simulations
• Pro Tractable model of
• discontinuous systems
• Con Computationally
• expensive

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Particle simulations the lattice solid model
Elastic stress transfer, rupture dynamics,
granular dynamics, elastic wave radiation,
fracture, friction, thermo-mechanical feedback,
thermo-porous coupling
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Shear experiments of a granular layer
KE
Time
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Shear experiment of granular layer
Cumulative Benioff strain
Sequence B
Sequence A
Time
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Stress field correlation function
r
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Compression of intact material
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Load-Unload Response ratio and critical
sensitivity
LURR X/X-
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Load-Unload response ratio
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LURR ensemble average
10 1 0.1
LURR
Time
10 0
events
Time
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What has been learned from particle simulations

• See evidence for CP-like behaviour
• See evidence for LURR mechanism
• Relation between AMR and LURR
• to be resolved
• Shows direct evidence for physical
• mechanism for earthquake forecasting

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Long range cellular automata
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Accelerating energy release correlation
evolution
p 2.0
p 0.4
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Short range cellular automata
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Accelerating energy release
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What is learned from CA simulations(See
Weatherley, Thurs, 1645)

• Can get either CP-like behavior or
• SOC behaviour depending on
• Dissipation
• Stress transfer ratio
• Visco-elastic interaction
• Two regimes 1. Forecasting possible
• 2. Forecasting not
  possible
• Where is the crust?

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What kind of complex system?
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Conclusion

• Elasto-dynamic systems like the crust may lie
  near the border between
• predictability and unpredictability

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References

• Mora, P. and Place, D., 2002, Stress Correlation
  Function Evolution in Lattice Solid
  Elasto-dynamic Models of Shear and Fracture Zones
  and Earthquake Prediction, Pure Appl. Geophys.,
  Vol. 159, No. 10.
• Mora, P., Wang, Y.C., Yin, C., Place, D., and
  Yin, X.C., 2002, Simulation of Load-Unload
  Response Ratio and Critical Sensitivity in the
  Lattice Solid Model, Pure Appl. Geophys., Vol.
  159, No. 10.
• Mora, P., Place, D., Abe, S. Jaume, S., 2000,
  Lattice solid simulation of the physics of
  earthquakes the model,results and directions,
  in GeoComplexity and the Physics of Earthquakes
  (Geophysical Monograph series no. 120), eds.
  Rundle, J.B., Turcotte, D.L. Klein, W., pp
  105-125 (American Geophys. Union, Washington,
  DC).
• Place, D., and Mora, P., Place, D. Mora, P.,
  1999, A lattice solid model to simulate the
  physics of rocks and earthquakes incorporation
  of friction, J. Comp. Phys., 150, 1-41
• Weatherley, D., Mora, P., and Xia, M.F., 2002,
  Long-Range Automaton Models of Earthquakes Power
  Law Accelerations, Correlation Evolution, and
  Mode Switching, Pure Appl. Geophys., Vol. 159,
  No. 10.
• Yin, X.C., Mora, P., Peng, K.Y., Wang, Y.C., and
  Weatherley, D., 2002, Load-Unload Response Ratio
  and Accelerating Moment/nergy Release Critical
  Region Scaling and Earthquake Prediction, Pure
  Appl. Geophys., Vol. 159, No. 10.