Experiments on Earthquakes in a Continuous Elastic Medium

¹ Departamento de Física Fundamental, Universidad Nacional de Educación a Distancia, Apartado 60141, Madrid 28080, Spain
² Departamento de Ciencia Aplicada a la Ingeniería Técnica Agrícola, Universidad Politécnica de Madrid, Madrid 28040, Spain

Abstract

We report on experiments on the dynamical behaviour in a model system for earthquake-like dynamics. Shear is imposed on a transparent gel in between two coaxial circular cylinders. The stress relaxations are investigated locally by means of photoelastic techniques. We found several dynamical regimes; three of them are reminiscent of the unstable solutions of the Burridge-Knopoff model. The fourth regime shows complex spatiotemporal behaviour involving events of many different sizes. For this last type of behaviour the statistics of event duration, event separation, and amplitude show exponential behaviour.