Choosing between the two Apollonius solutions when locating a microseismic event

John C. Bancroft

The location and clock-time of a microseismic event can be computed analytically using the first arrival clock-times at four known receiver locations, assuming the velocity is known. The process is based on the Apollonius method that produces two solutions, either being possible for the same receiver geometry. The difficulty in choosing the correct solution is presented along with a method for identifying the best solution.