IASPEI - Picture Gallery

IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy
(S) - IASPEI - International Association of Seismology and Physics of the Earth's
Interior
JSS001 Poster presentation 1731
Comparison between different microscopic properties of a 2D lattice on its
macroscopic behaviours
Dr. Shayesteh Mehrabian
EARTH PHYSICS INSTITUTE OF GEOPHYSICS, UNIVERSITY OF TEHRAN IASPEI
Ahmad Amini
A set of 2D numerical biaxial compression experiments has been performed to illustrate simulation of
fracturing behavior using the random lattice. Unlike laboratory experiments and field studies, numerical
experiments allow all quantities to be measured at any scale resolved by the model. With advances in
numerical simulation methodology and High Performance Computing, they provide a means to study the
processes underlying earthquake phenomena, emergent behavior such as space-time patterns for long
seismicity sequences or localization phenomena, and the impact of different potentially important
microphysics on fault behavior. Numerical experiments of biaxial compression using a random lattice
illustrate that the new approach is capable of simulating typical rock fracture behavior using only simple
radial interactions between particles. This 2D lattice solid model (LSM) is a particle-based numerical
model that was developed to simulate the nonlinear dynamics of earthquakes. Occurrence of many
microphysical processes can strongly affect the macroscopic behavior of the faulting processes but in
previous works only few of them (such as friction) have been considered in the numerical experiments.
Using simple particle interaction, the model can be calibrated with laboratory experiments of rock
fracture. However, not all macroscopic parameters can be matched with laboratory results so more
complex particle interactions may be required. In this study, thermal expansion and pore fluid pressure
which affect the macroscopic behavior of rocks are incorporated in the model. With the capability of
easily adding new features in the model such as rotational dynamics, microscopic breakage through
bending, fluid and thermal effects, the model can be more easily calibrated against laboratory
observations and provides a means to simulate complex phenomena such as localization processes, and
to study the dynamics of complex systems such as fault zones. With the ability to add new microphysics,
the model is presently capable of simulating physical processes such as friction, fracture,
granular dynamics and thermal effects including thermo-mechanical and thermo-porous feedback.
Keywords: lattice solid, microphysical processes, thermal expansion