Abstract：The first break times from seisrnic source and receiving point to any reflection point can be calculated respectively by solving eikonal eqllation with the use of finitedifference.Then the two first break times are added together to bring relationalcurve between the total travel time and the horizontal coordinates of reflection inter-face.From Fermat principle,we can know that the time corresponding to extremepoint of the curve is reflection travel time,and horizontal coordinate correspondingto the extreme point is the location of reflection point.This method can be used toestirnate both travel times and ray paths of the reflection waves which are receivedby all geophone groups.It is efficient,accurate and adaptable to complicated struc-ture model.
