Abstract: In this paper, a general method has been developed for determining earthquake parameters on basis of one or several phases of recorded waves when the travel time tables are given. The problem is reduced to minimizing some criterion function. On the computer an efficient and direct searching technique, the Powell method is proposed. This technique allows the requirements to the starting value to be less critical. Generally, the location of a station with the least arrival is selected as a start. From the arrival data of a single phase, two phases and the first motion of unknown phases, the determinations of parameters of earthquakes are illustrated and some numerical examples given. Computations for more than 100 local and near earthquakes recorded by certain seismic station networks are described.