Computations of seismic wave propagation velocities in ocean bottom sediments from reflected waves traveltime curves
Abstract
The velocity of seismic waves in a thin layer of sediments in the ocean is usually determined using the approximate Dix formula, but the latter has a number of limitations in large part attributable to its derivation. These limitations are reviewed. In its derivation use was made only of the first two even terms in the expansion of the traveltime curve for reflected waves. S. N. Medvedev found a more precise analytical expression for velocity which is derived using the first three terms of the expansion. The Medvedev algorithm, outlined in this article, was checked in a theoretical model and using experimental data obtained on the 28th cruise of the Dmitriy Mendeleyev. The Dobrinskiy program was used in solving the direct seismic problem for horizontally bedded thick layers with a constant velocity and theoretical traveltime curves were computed from the bottom of sedimentary layers of different thicknesses; these theoretical traveltime curves were then introduced into a program for the inverse seismic problem. It is shown that the Medvedev algorithm makes it possible to compute the stratum velocities of propagation of seismic waves in thin sedimentary layers of the ocean with an accuracy to 0.05 km/sec.
 Publication:

USSR Report Earth Sciences JPRS UES
 Pub Date:
 June 1985
 Bibcode:
 1985RpESc.......46M
 Keywords:

 Ocean Bottom;
 Ocean Currents;
 Sediments;
 Seismic Waves;
 Wave Propagation;
 Algorithms;
 Computer Programs;
 Wave Reflection