Hi Larry, Here's a suggestion for WinQuake. It would be nice to have a marker for the beginning of the Love (LQ) and Rayleigh (LR) waves. Based on the "Principles Underlying the Interpretation of Seismograms" travel time chart, you could easily compute their approximate start times from: origin time plus (distance in degrees)/2.43 for LQ and the same formula, but divide by 2.2 for LR. You could plot these phases for distances of 20 degrees and greater. This would certainly work for depths as deep as 50 km. For deeper depths, down to at least 200 km, one can often see surface waves. I'm not sure if the arrival times would need to be delayed for these depths, but you could use the same formulas and people would have to understand that these are the earliest start times, that the arrivals are emergent, that the duration of the waves increases with greater epicentral distance, that the start times are somewhat dependent on how much of the path is oceanic and how much is continental, and that surface waves become weaker and weaker as the depth increases. Clearly surface waves are not helpful for locating an earthquake, but it would be nice to know approximately when they should start arriving. Just a suggestion. Others may have a better approach. Cheers, John John C. Lahr 1925 Foothills Road Golden, CO 80402 Phone: (303) 215-9913 john@........ http://lahr.org/john-jan/science.html __________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>