Application of Fermat's principle for seismic tomography. Part I: physical foundations Aplicación del principio de Fermat a la tomografía sísmica. Parte I: fundamentos físicos

This article has the purpose of analyzing the nature of earthquakes, deducing the fundamental equation of seismic tomography. To get there, we must analyze the importance of building Physics from some fundamental principles, specifically from the principle of least action. This can be applied to seismic rays thus leading to the principle of Fermat, by using this principle, originally enunciated for optics, we can get the fundamental equation of seismic tomography. We must also analyze the implications of the equation of the tomography for the resolution of the direct problem and the inverse one. All this quantity of theory is essential to get seismic images of Pisayambo region.