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first arrivals fade rapidly along line. Jagged topography may account for much of this. Strong PmP seen 30-50 km (sh. 2550-2650) Pg craps out, even on 2-8 Hz trace, before 30 km (sh. 2600). frequency content observation: near traces 2700-2750 (10-15 km) picks are easy with 2-16 Hz bpf. However, the use a 2-8 Hz filter shifts the appearent arrival time by nearly two cycles or 0.25 seconds weak arrivals sh 2600-2685 (30-15 km) Mystery phase from sh. 2670-2700. (?) |