Biomedical subjects
Publications and source records attributed to L Margerin.
We report the observation of weak localization of seismic waves in a natural environment. It emerges as a doubling of the seismic energy around the source within a spot of the width of a wavelength, which is several tens of meters in our case. The characteristic time for its onset is the scattering mean-free time that quantifies the internal heterogeneity.
We present theory and numerical simulations to model seismic wave propagation in the Earth crust. We compare them to observations made in Mexico.
Equipartition is a first principle in wave transport, based on the tendency of multiple scattering to homogenize phase space. We report observations of this principle for seismic waves created by earthquakes in Mexico. We find qualitative agreement with an equipartition model that accounts for mode conversions at the Earth's surface.
Calculation of coherent backscattering of elastic waves in an infinite isotropic random medium is presented. Despite the simplicity of this geometry, this calculation highlights several specific aspects for seismic detection: near field detection, polarization, and the symmetry of the source. Line profiles and enhancement factors are seen to be time independent and are calculated for kinetic, shear, and compressional energy.