On time-distance curves for Pn waves in the Friuli earthquake of 6 May 1976
Journal: Annals of Geophysics
Year: 2010

Results obtained in the study of the arrival times of the Pn phase forthe Friuli earthquake of 6 May 1976 (H = 20h00™15s,5; φ = 46° 16'30" N; λ = 13° 06' 00" E; M = 6.3) with respect to the epicentral distance arereported. Particular emphasis is given to the fact that the travel-timecurves relative to the Pn waves and the corresponding equations are onlyvalid for selected alignment. By plotting the time-distance curves it waspossible to derive the depth of the lower surface of the upper mantle f