SEISMIC MODEL EXPERIMENT ON THIN LAYERS*

Seismic two‐dimensional model experiments have been made at the Laboratory of Fondazione Lerici in the Polytechnic School of Milan.

For this purpose the Laboratory has developed and constructed a complete equipment including pulse generators, piezoelectric transducers and amplifiers for detecting the waves propagation through the models.

We record here experiments concerning reflections from horizontal layers thin in relation to the wave lengths propagated through the media.

Layers, with a thickness from a 50th of the total wave length to several wave lengths were used. These strata consist of materials sometimes with lower and sometimes with higher velocities than the homogeneous surrounding medium.

The object of this investigation was to clarify the effects of the very thin reflecting layers, individually and in combination, on the reflected arrivals and to determine the influence of the layers upon the reflected energy in comparison with their thickness.

We are also studying at what minimum distance, as a fraction of the wave length, the reflection of a horizon appears on the seismogram in an independent event.