Bob, When I added the IASP91 tables to WinQuake I was surprised to see the P and S wave tables went out farther then the JB tables. Since the P wave goes into a shadow at around 106 deg (1 deg = ~111km) I'm not sure what the tables represent past this distance. -Larry Cochrane Redwood City, PSN At 05:11 PM 5/6/00 EDT, you wrote: >Hello all: > >The recent quake on the Minahassa Peninsula, Sulawes reminded me of a >question that I have had for some time about the use of the IASP91 table in >Winquake. > >The teleseismic table in Winquake cannot be used to calculate the P and S >wave arrivals for distances beyond about 12,000 km because beyond this >distance the arrival location is in the "shadow" of the earth's core and >arrivals are modified by travel through or along the boundary of the core (my >location is about 15,000 km from the Minahassa event location). Thus, >Winquake gives the error message "Can't place P and S markers" when one tries >to calculate P and S wave arrivals beyond this distance using the teleseismic >table. Yet if one uses the IASP91 table beyond the critical distance, P and >S markers can be calculated. I guess I don't understand what the IASP91 >table does that the teleseismic table doesn't do. Are the P and S wave >arrivals that can be calculated using the IASP91 "real" beyond the critical >distance? I noticed that my event record using the IASP91 table to calculate >P and S arrivals and some of the other event records posted for the Minahassa >quake showed 3 to 4 minutes difference between the calculated P wave arrival >and what looked like the first arrival on the record. > >Can someone shed some light on this issue? > >Thanks, > >Bob Laney >Herndon, VA >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with >the body of the message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>