Complexity in brittle deformation

Study of the dynamics involved in complexity internal to earthquakes and to populations of earthquakes and faults.

Faults and earthquakes spontaneously produce populations which obey fractal size and spatial characteristics. This behavior, which cannot be predicted from the physics of the individual faults or earthquakes, represents a type of complexity known as self-organized criticality. Applied Physics graduate student Chrysanthe Spyropoulos, working with L-DEO's Chris Scholz and Bruce Shaw, has been developing a dynamic numerical model of a population of cracks to try to develop a better understanding of the underlying physics of this behavior. This builds on earlier work by Shaw on Burridge-Knopoff type models of earthquakes that do exhibit this type of scaling.

This theoretical work complements an observational study by DEES graduate student Anu Gupta who is studying fault-fault interactions in fault populations, based on field work in North Carolina and Djibouti. This work is in cooperation with Chris Scholz, and, in Djibouti, with Isabelle Manighetti, a postdoctoral visitor from Paris, who will lead a geological expedition to her field area in Djibouti early next year. Both Gupta and Scholz will participate.

Spyropoulos, C., C. Scholz, and B. Shaw, A model for the growth of a population of cracks, Fall meeting, AGU, 1997.

Gupta, A., and Scholz, C., Validity of elastic models in predicting fault displacement fields, subm., J. Geophys. Res. 1997.