Reflection and transmission characteristics at the ground surface by the electromagnetic plane waves from under ground

In recent years, observations of anomalous electromagnetic emissions possibly related to earthquakes have been carried out with the aim of earthquake prediction. The observation points are almost near the ground surface, and the receiving frequencies are less than several megahertz. As the attenuation is strong in the ground, and as the observed data are few as yet, these data are not entirely acceptable. Some basic data are presented which may help to clarify this situation. Numerical results on the reflection and transmission coefficients are reported. The planes of constant phase and constant amplitude, the phase velocities, and the propagation directions are discussed.<>