A comparison of earthquake magnitude with T-phase strength

Records from SOFAR-depth hydrophones at widely spaced locations in the North Pacific were scanned for earthquake T phases. A source solution was obtained by computer for T-phase arrivals correlated at four or more hydrophones. Using this method, the number of events located on the North Pacific rim is about ten times greater than the number located by conventional body-wave determinations. It is concluded that the capability for location of earthquakes by T-phase arrivals extends down to about magnitude 3.6 for the North Pacific rim.