On the localization of seismic events

Source location of seismic events is a cruciial item in seismology. Different methods of source location are considered and discussed, with particular emphasis on the determination of the azimuth and the angle of emergence of the first recorded impulse, which requires that all of the three components of ground displacement are measured at the seismometic station. The greatly increased accuracy and sensitivity of the present instrumentation and the possibility of digital recording of seismic data ask for reconsideration of the azimuth-angle-of-emergence method, especially for the location of seismic events on a regional scale