The direct P phase is not detected beyond 103 degrees because it is  in the 
shadow of the core. There are phases which pass through the core. If you  want 
a good picture of how seismic waves propagate, try running the Seismic  Waves 
program by Alan Jones,  _http://www.geol.binghamton.edu/faculty/jones/_ 
(http://www.geol.binghamton.edu/faculty/jones/) 
 
  I have a program "Travel Time" which might also be useful. It plots  and 
uses the Jeffreys and Bullen Seismological Tables to list the time of arrival of 
 an event at your station coordinates. Just enter your station coordinates, 
and  the event line from NEIC, load file "BigList.jb1, and you can get travel  
and arrival times for all JB files listed to the clipboard, and a plot of all  
phases for all distances. The program can be downloaded from:
 
  _http://www.jclahr.com/science/psn/mcclure/traveltime/index.html_ 
(http://www.jclahr.com/science/psn/mcclure/traveltime/index.html) 
 
  For a discussion of some special core waves, consult 
 
  _http://www.seismosoc.org/publications/SRL/SRL_72/srl_72-1_eq.html_ 
(http://www.seismosoc.org/publications/SRL/SRL_72/srl_72-1_eq.html) 
 
  Hope this is helpful
 
Bob





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in the shadow of the core. There are phases which pass through the core. If=20=
you=20
want a good picture of how seismic waves propagate, try running the Sei=
smic=20
Waves program by Alan Jones,  http://www.geol.bingh=
amton.edu/faculty/jones/
 
  I have a program "Travel Time" which might also be useful. It pl=
ots=20
and uses the Jeffreys and Bullen Seismological Tables to list the time of arriva=
l of=20
an event at your station coordinates. Just enter your station coordinates, a=
nd=20
the event line from NEIC, load file "BigList.jb1, and you can get trave=
l=20
and arrival times for all JB files listed to the clipboard, and a plot of al=
l=20
phases for all distances. The program can be downloaded from:
 
  htt=
p://www.jclahr.com/science/psn/mcclure/traveltime/index.html
 
  For a discussion of some special core waves, consult 
 
  h=
ttp://www.seismosoc.org/publications/SRL/SRL_72/srl_72-1_eq.html
 
  Hope this is helpful
 
Bob