Abstract：In order to know interval velocity in layered acoustic medium,ve一locity analysis is made using wave field continuation and fuzzy decisiontheories.First,surface mufti-offset seismic wave field is continued toobtain continued mufti-offset wave field by making use of trial velocity(νi)，two way travel time(τi)and continuation equation that has doublesquare roots in Fourier domain,Then,the similarity degree of contin-ued wave-field values in offset direction is calculated in terms of coher-ent ciiterion,and used as similarity degree at(νi,τi)point，which is call-ed alternate point.Next,the similarity degree on νi-τi plane is ob-tamed by repeating the above steps for a new(νi,τi) point,and the si-milarity degree is converted into brightness at each alternate point accor-ding to similarity degree,trend approach and minimum distance eriter-ions,Finally,velocities and two-way travel time values can be auto-matically picked up in the light of each point brightness so that intervalvelocities and optimum two-way travel time values relating to reflec-tors are obtained from the mufti-offset wave field.The experimental re-sults of both theoretical model and real datashow that interval velocity obtained using this method is accurate,without accumulated errorand that this method may be applicable to thecase where reflection signalsare weak and noises strong.
