The seismic refraction method: A viable tool for mapping shallow targets into the 1990s

Abstract

Geometrical considerations show that first arrivals can be recorded from below hidden layers. A certain minimum amount of data must be collected in order to resolve lateral versus vertical subsurface changes and thereby to determine the interpretation method. Field procedures, therefore, are independent of the interpretation method. The optimum XY parameter in the generalized reciprocal method (GRM) of processing refraction seismic data is significant as a quality control factor in refraction data interpretation. By comparison of the optimum XY value that is recovered through velocity analysis and time‐depth function analysis with a value for optimum XY that is calculated from the migrated depth section, the hidden‐layer condition can be recognized. In addition to identifying the hidden‐layer condition on the basis of first arrivals alone, the GRM allows the hidden layers to be accommodated; and depth precisions of less than 5% are possible.