Hi Bob,

I'm not sure of the working of Larry's program, but you can see the expected
arrival times at your station for any earthquake by using this page:
http://geohazards.cr.usgs.gov/tt/

There is also a travel time graph - an old one that is a bit hard to read - but
your can see how P becomes P diffracted and then dies out.  PKP is a few
minutes later.

John

At 03:11 PM 5/6/00 , you wrote:
>  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

John C. Lahr
1925 Foothills Road
Golden, CO 80402
(303) 215-9913
http://lahr.org/john-jan/science.html
__________________________________________________________

Public Seismic Network Mailing List (PSN-L)