Etude sur modele ultrasonique du probleme des couches minces en sismique refraction
Journal name: Geophysical Prospecting
Issue: Vol 9, No 1, March 1961 pp. 60 - 73
Info: Article, PDF ( 878.77Kb )
Difficulties may arise in refraction seismic surveys in the case of thin layers.
Seismograms have been realized by means of ultrasonic model techniques and have led to some results about the propagation of refracted waves along thin layers. The velocities of propagation have been determined as a function of the layer thickness.
When the layer thickness is small compared to the wave length, it is shown that:
— the velocities of propagation of refracted waves can be up to 6 % less than the velocities along thick layers.
— the attenuation of amplitude with distance becomes large.
— the determination of depth from measurements of delays gives doubtful results.
Experiments have been run on two dimensional models but extension of the results to three dimensional cases is possible.