Abstract: An improved geophone for seismic prospecting is disclosed which features plural magnets of varying mass oscillating with varying frequencies within one or plural coils whereby the frequency response of the geophone may be optimized.

Abstract: In seismic exploration, the response characteristics of an array of seismic sources is displayed by contours of equal values of amplitude response as a function of azimuth and dip angle in a stereoscopic polar projection. The projection includes a center point on an axis extending away from the center point representing amplitude response at locations on the line of exploration. Points disposed circumferentially about said axis amplitude response at different azimuth angles from the line of exploration and points at different radial distances from the center point represent amplitude response at different dip angles.

Abstract: In marine seismic exploration, measurements of reflectivity and water depth are made from seismograms produced by the firing of a seismic energy source towed by a marine vessel. The measurements are made by generating the auto-correlation coefficients of a window of the seismogram and combining these coefficients for different time lags. The time lag producing the minimum energy in the combined autocorrelation coefficients represents water depth. The reflectivity of the water bottom is obtained by generating an estimate of the reflectivity from the values of the auto-correlation function of the window, and modifying this estimate by a factor which converts the estimate to the reflectivity. The measured water depth and reflectivity are converted into an inverse operator. A linear array of sources is then fired in a sequence such that the acoustic pulses combine to produce a resultant acoustic pressure wave having the inverse time domain operator characteristics.