The effect of shallow coal seams on recording seismic reflections from deeper beds is examined by means of synthetic seismograms. An expression based on acoustic impedance permits the calculation of reflection coefficient, as a function of frequency, and synthetic seismograms, with or without surface multiples. Results indicate that using lower frequencies (5-25 Hertz) would permit recording below the coal measures encountered in a particular hole in the Central Sydney Basin.
Figures & Tables
Seismic Wave Propagation: Collected Works of J. E. White
This first chapter sets the stage for the later technical development of Dr. Whit’s career in applied seismics. Experiments, f’wst at the Acoustics Laboratory of the Massachusetts Institute of Technology and later at Mobil Oil and Marathon Oil, provided insight into the general problems of impedance measurements, transduction, filtering, and attenuation. These papers also serve as a bridge to show geophysicists how theft own experiments in seismology naturally interface with (indeed, arose out of) the larger world of sound measurements in air and water. These experiments demonstrate the power of geometrically constrained experiments to allow verification of approximate (and in some cases, exact) theories of sound.