The generalized reciprocal method of seismic refraction interpretation /
Palmer, Derecke
The generalized reciprocal method of seismic refraction interpretation / by Derecke Palmer ; edited by Kenneth B. S. Burke - vii, 104 p. : il. ; 26 cm.
Incluye referencia bibliográfica: p. 87-89 e índice
The generalized reciprocal method (GRM) is a technique for delineating undulating refractors, at any depth, from in-line seismic refraction data consisting of forward and reverse traveltimes. The arrival times at two geophone positions, separated by a variable distance XY, are used in refractor velocity analysis and time-depth calculations. At the optimum XY separation, the rays to each geophone emerge from near the same point on the refractor, and the refractor velocity analysis and time-depths are the most detailed. Perpendicular thicknesses are obtained from time-depths and the depth conver¬sion factor. Loci, rather than actual depth points, are determined, and the surface of the refractor is taken as the envelope of these loci. The depth conversion factor is independent of dip for angles up to about 20 degrees; thus depth calculations to an undulating refractor are particularly convenient, even when the overlying strata have velocity gradients. The presence of undetected layers can be inferred when the observed optimum XY-value differs from that derived from the computed depth section. The optimum XY-value can be used to form an average velocity which permits accurate depth calculations with commonly encountered velocity contrasts.
0931830141
METODO DE REFRACCION SISMICA
622.159 / P3 1980
The generalized reciprocal method of seismic refraction interpretation / by Derecke Palmer ; edited by Kenneth B. S. Burke - vii, 104 p. : il. ; 26 cm.
Incluye referencia bibliográfica: p. 87-89 e índice
The generalized reciprocal method (GRM) is a technique for delineating undulating refractors, at any depth, from in-line seismic refraction data consisting of forward and reverse traveltimes. The arrival times at two geophone positions, separated by a variable distance XY, are used in refractor velocity analysis and time-depth calculations. At the optimum XY separation, the rays to each geophone emerge from near the same point on the refractor, and the refractor velocity analysis and time-depths are the most detailed. Perpendicular thicknesses are obtained from time-depths and the depth conver¬sion factor. Loci, rather than actual depth points, are determined, and the surface of the refractor is taken as the envelope of these loci. The depth conversion factor is independent of dip for angles up to about 20 degrees; thus depth calculations to an undulating refractor are particularly convenient, even when the overlying strata have velocity gradients. The presence of undetected layers can be inferred when the observed optimum XY-value differs from that derived from the computed depth section. The optimum XY-value can be used to form an average velocity which permits accurate depth calculations with commonly encountered velocity contrasts.
0931830141
METODO DE REFRACCION SISMICA
622.159 / P3 1980