A Model Experiment of Electromagnetic Wave Propagation over Long Distances using Waveguide Terminology

Abstract

Electromagnetic (EM) waves observed by telecommunication engineers ahead of earthquakes are controversial because they should not propagate over long distances from the hypocenter due to dissipation in the conductive Earth. A model of an earth crust dielectric waveguide was proposed and discussed with an earth atmospheric waveguide and tested in a laboratory scaling simulation experiment using a granite slab and an EM generator antenna at the hypocenter for the Kobe Earthquake. The mappings of evanescent and wave-ripple standing waves were obtained by scanning a detector antenna over the Japanese island archipelago model. Theoretical relations of the field intensity Δ V , such as log Δ V =0.375 M W + c , where M W and c are the moment magnitude and a constant, respectively have been derived by considering EM waves from an ensemble of dipolar charges at a fault zone. The theoretical scaling law is consistent with the empirical one.