Hi Gary,
from what I have read, the T waves travel at approximately 1500m/s. I =
live about 2km from the ocean and measured the velocity at 1550m/s. I =
suppose the conversion from a 'water' wave back to a seismic wave must =
consume enormous energy generating a shock wave. I have seen these =
before with events from Fiji and Vanuatu region but never realised what =
they were, assumed them to be bug quakes etc. On a  local TV news report =
a trawler fisherman recounted how the fish suddenly vanished during his =
night of fishing, he was unaware of the event but the fish were probably =
shocked out of their scales :).
I found a good article on T waves at  =
http://www.earth.northwestern.edu/people/emile/PDF/EAO050.pdf

regards
Dale
  ----- Original Message -----=20
  From: Gary Lindgren=20
  To: psn-l@.................
  Sent: Tuesday, July 21, 2009 3:58 AM
  Subject: RE: T wave


  Dale,

  How do you differentiate the "T" and the Love and Raleigh waves.

  Gary

  =20

  =20

  =20

  =20

  =20

  From: psn-l-request@.............. =
[mailto:psn-l-request@............... On Behalf Of Dale Hardy
  Sent: Sunday, July 19, 2009 4:43 PM
  To: PSN
  Subject: T wave

  =20

  The recent M7.8 New Zealand EQ produced " T " waves which showed up =
very strongly on my geophone.

  "T" phase & is seen for big events - it is transmitted through the =
ocean water, rather than through the rock below  - hence it is slower  - =
only seen for events under oceans ( & probably have to be shallow as =
well)

  =20

  http://www.daleh.id.au/New_Zealand_M_7.8_T_wave.gif

  =20

  regards

  =20

  Dale



-------------------------------------------------------------------------=
-----



  No virus found in this incoming message.
  Checked by AVG - www.avg.com=20
  Version: 8.5.392 / Virus Database: 270.13.20/2249 - Release Date: =
07/19/09 17:59:00







Hi Gary,
from what I have read, the T waves travel at =
approximately=20
1500m/s. I live about 2km from the ocean and measured the velocity =
at=20
1550m/s. I suppose the conversion from a 'water' wave back to a seismic =
wave=20
must consume enormous energy generating a shock wave. I have seen =
these=20
before with events from Fiji and Vanuatu region but never realised what =
they=20
were, assumed them to be bug quakes etc. On a  local TV news =
report a=20
trawler fisherman recounted how the fish suddenly vanished during his =
night of=20
fishing, he was unaware of the event but the fish were probably shocked =
out of=20
their scales :).
I found a good article on T waves at =
 ht=
tp://www.earth.northwestern.edu/people/emile/PDF/EAO050.pdf
 
regards
Dale

  
----- Original Message ----- 
  From:=20
  Gary=20
  Lindgren 
  
To: psn-l@.............. 
  
Sent: Tuesday, July 21, 2009 =
3:58=20
AM
  
Subject: RE: T wave
  


  

  
Dale,
  
How=20
  do you differentiate the =93T=94 and the Love and Raleigh=20
  waves.
  
Gary
  
 
  
 
  
 
  
 
  
 
  

  
  
From: psn-l-request@...............
=20
  [mailto:psn-l-request@............... On Behalf Of Dale=20
  Hardy
Sent: Sunday, July 19, 2009 4:43 PM
To:=20
  PSN
Subject: T wave
  
 
  

  
The recent M7.8 New Zealand EQ produced " =
T "=20
  waves which showed up very strongly on my =
geophone.
  

  
"T" phase & is seen for big events - it is =
transmitted=20
  through the ocean water, rather than through the rock below  - =
hence it=20
  is slower  - only seen for events under oceans ( & probably =
have to=20
  be shallow as well)
  

  
 
  

  
http://www.d=
aleh.id.au/New_Zealand_M_7.8_T_wave.gif
  

  
 
  

  
regards
  

  
 
  

  
Dale
  

  


  

No virus found in this incoming message.
Checked by AVG =
-=20
  www.avg.com 
Version: 8.5.392 / Virus Database: 270.13.20/2249 - =
Release=20
  Date: 07/19/09 17:59:00