Response of random dielectric composites and earthquake models to pulses: prediction possibilities

Following the success of the study of response to local short-duration pulses (of magnetic field, additional ‘sands’, etc.) on magnetic systems and the BTW (sand-pile) model, to locate accurately the respective critical points, the responses to similar short duration pulses (of electric field, of ‘mechanical pushes’ on tectonic plates, etc.) have been studied here numerically for metal-insulator composites before dielectric breakdown and the Burridge-Knopoff (earthquake) model before the critical avalanches. The breakdown susceptibility (defined in the text), obtained from such response behaviour, indicates universal behavior near the catastrophic breakdown or the self-organised critical points. We show that the breakdown (electric) feld for random metal-dielectric composites can be located accurately much before the breakdown, by extrapolating the inverse breakdown susceptibility to its vanishing point. Similarly, the growth of the susceptibility, coming from the stress correlations, in the Burridge-Knopoff model of earthquakes is shown to be exponential in time. Prediction of the earthquake point (in time) is also possible in the model from the study of its inverse logarithm with straight-line extrapolation to its vanishing point.