- The intensity of a 200 kHz signal decreased during a large
- But - subsequent structural failure raises questions of
alignment, path obstruction, etc.
- Ascribing the attenuation to Rayleigh scattering by sand
particles requires M*d^3 = (30 g/l)*(200 microns)^3 -
- Strong interference between direct and surface-reflected ray
complicates coherent detection for measuring time delays.