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entire set of shots show weak arrivals. Even near shot 1800 where range is < 10 km. Instrument is opposite shots on other side of caldera. PmP-like feature at sh. 1870-1910 (~37 km)occurs at place where range is not changing significantly. PmP appears steeper on than most though the topography is not drastic. sh. 1840-1860 show a very bright arrival near or behind the missing first arrival. With high amplification and 2-8 Hz filter, 3? cycles are seen in front of bright spot. However, filter may create some of this. Picked as x2, this set of arrivals may be encountering the caldera M.C. bright spot arrivals appear set back from closer traveltime even considering topography. |