Complex Geophysical Systems
From morphogenesis to population dynamics

In Earth science, natural systems exhibit a high degree of structural and compositional heterogeneity as well as a long and complicated history. Since the 1970's and the development of the theory of plate tectonics, geophysicists have described a multitude of simple causal dependencies. Nevertheless, our understanding of extreme events and their prediction are still out of reach. A reason may be that all these systems have been analysed through a formalism which does not take into account lower/higher levels of interaction.

In the mean time, scientists in many disciplines have come to the conclusion that patterns of interaction between different elements of a system over time can explain accurately the diversity of the observations. Defined as "complex systems", these systems are characterized by a mechanism of emergence which is impossible to anticipate from individual structures alone, but only from the collective behaviours that they are able to produce when they are acting on one another as a whole. Then, more than the underlying properties of each structure, the nature of the interactions allow to understand the macroscopic expression of a population of structures. In addition, due to the absence of a simple causality chain, complex systems are known to be resilient and likely to produce under many different forcing similar types of behaviours.

In our work, we develop methods for the description, understanding and prediction of complex geophysical system across a range of natural phenomena. The objective is to develop interdisciplinary research collaboration to investigate dynamics of interacting structures in geophysics. See example for

             Dunes                                                       Earthquakes                                                      Slopes

                                                                 Barchan dunes in Morocco

                                Seimicity of the Hector Mine Fault Zone, southern California, USA

                                           Seismicity of the San Andreas Fault Zone, central California, USA    

uuu Discrete numerical methods include

uuuuuuuuuuuuuuuu Cellular automaton models with multiple range of interaction in geophysics

uuuuuuuuuuuuuuuu Cellular automaton models for landscape dynamics