PSN-L Email List Message
Subject: Re: P-waves
From: Bob McClure bobmcclure90@.........
Date: Fri, 25 Mar 2011 11:42:11 -0400
I disagree with your hypothesis. Transverse motion is only possible with a
wave of finite cross-section. A P wave has a more-or-spherical wavefront and
is not a beam of sound. Even a beamed wave would have no transverse motion
at its center axis.
Bob
On Thu, Mar 24, 2011 at 5:17 PM, Brett Nordgren wrote:
> Dave,
>
> I think in real world seismology, not everything always exactly follows the
> simple theory. We see P waves quite well on our verticals. For one thing
> they are body waves and commonly approach the station from an angle below
> the horizontal. Also I think there is always a transverse motion associated
> with compression waves like P waves--look up Poisson's Ratio. I would
> normally expect them to have a transverse motion of very roughly 1/3 the
> amplitude of their longitudinal motion.
>
> Regards,
> Brett
>
>
> At 03:57 PM 3/24/2011, you wrote:
>
> Found what I was looking for ,,,,, a animation of a P wave
>>>
>>
>> http://www.geo.mtu.edu/UPSeis/images/P-wave_animation.gif
>>
>> notice there is NO vertical motion, it is totally longitudinal
>> P waves travel like sound waves do :)
>>
>> cheers
>> Dave
>>
>>
>
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>
I disagree with yo=
ur hypothesis. Transverse motion is only possible with a wave of finite cro=
ss-section. A P wave has a more-or-spherical wavefront and is not a beam of=
sound. Even a beamed wave would have no transverse motion at its center ax=
is.
Bob
On Thu, Mar 24, 201=
1 at 5:17 PM, Brett Nordgren
<brett3nt@.............> wrote:
Dave,
I think in real world seismology, not everything always exactly follows the=
simple theory. =A0We see P waves quite well on our verticals. =A0For one t=
hing they are body waves and commonly approach the station from an angle be=
low the horizontal. =A0Also I think there is always a transverse motion ass=
ociated with compression waves like P waves--look up Poisson's Ratio. =
=A0I would normally expect them to have a transverse motion of very roughly=
1/3 the amplitude of their longitudinal motion.
Regards,
Brett
__________________________________________________________
Public Seismic Network Mailing List (PSNLIST)
To leave this list email PSNLIST-REQUEST@.............. with the body of the m=
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See h=
ttp://www.seismicnet.com/maillist.html for more information.
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