How to advantageously manage the effective ellipticity of seismic waves in metamaterials?

Abstract

In addition to the research advances made on the interaction of seismic waves with rigid elements in the ground or with holes, this paper explores the possibilities of acting on the free surface displacement. In particular it is about looking at the beneficial effects of a decrease of horizontal surface displacements in case of Rayleigh waves which directly affect the design of buildings. Exploring this idea, a promising way is to achieve a complete dynamic artificial anisotropy by implementing geometrical elements, full or empty, in the soil. For body or surface waves, the physical process is the coupling of the scattered field displacement with local resonances of stiff elements implemented in the soils. This approach could theoretically lead to enhanced wave-path control, attenuation by energy-dissipation, etc. The Holy Grail would be the achievement of a complete shield for all seismic wave polarizations over a large frequency bandwidth with a seismic metamaterial reminiscent of a perfect flat lens and a seismic cloak detouring surface seismic waves around a designated area.