A new method for earthquake source location and velocity structure determination is formulated based on the Bayes theory. The medium is represented by homogeneous layers with plane-dipping interfaces. Inversion of the arrival-time data yields the velocity parameters, the hypocenters, and the origin times of the earthquakes.
A linear combination of model parameters is included in the method, and the determination of the standard deviations of the estimated parameters is elaborated. The possibility of constraining a linear combination of two model parameters are used for the P-to-S velocity ratio. Because the travel time cannot be found analytically, the forward problem is solved numerically, namely, by two-point raytracing.