I also noticed that the M7.8 NZ quake showed up
strongly on my 4.5 Hz geophone, and when I looked
at the power spectra most of the energy appeared
to be above 1 Hz.  In my previous large teleseismic
geophone detections my power spectra have shown peaks
around 0.02-0.04 Hz.  Are T waves typically at
higher frequencies?

Dave

> ----- Original Message -----
> From: "Dale Hardy" 
> To: "PSN" 
> Sent: Sunday, July 19, 2009 4:43 PM
> Subject: T wave
>
>
> 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)
>
> http://www.daleh.id.au/New_Zealand_M_7.8_T_wave.gif
>
> regards
>
> Dale

__________________________________________________________

Public Seismic Network Mailing List (PSN-L)