On the attached snap of the Terramon window, the second event is a largesh EQ in Middle East. The EQ distance to H1 is 1000km shorter than the distance to L1 but the computed site velocity is 1/2 at H1 versus L1. Is this one of those cases where the waves arrive first from opposite directions and so the crust encountered is different for the travelling surface waves? Interesting info I'm sure everyone wants to know. I see a similar descrepency for the G1 and V1 velocities but those waves are certainly travelling on the same direction. Maybe it is just the local site geology being taken into account? HunterG? Thanks-H
Hey Hugh!
Apologies for the late response. I'm going to paraphrase what Michael Coughlin told me in a recent discussion.
We have historically attributed the different behavior to the sites themselves rather than to any particular selection effect from LHO and LLOs location relative to most EQs. Amplitude as a function of EQ direction dependence would be interesting to look at, as we essentially fit it away by only taking distance into account. Might be a good summer project for someone.
--Hunter