Interesting! But you can definitely see it in the horizontals. A high pass
filter would bring it out...

---
Dr. Judson L. Ahern
Professor Emeritus, Geophysics
School of Geology & Geophysics
University of Oklahoma
Norman, OK 73019
jahern@......     W5JA


On Sun, Oct 6, 2013 at 1:22 PM, Brett Nordgren wrote:

> Hi All,
>
> Dave N. has been playing with an old Guralp 24-bit digitizer, attempting
> to make it work in a predictable manner.  Yesterday he hooked it up to his
> Trillium 120 to do some testing and today he recorded a quake that I think
> he said was a 4-something in Mexico, though I don't seem to find it on the
> USGS site (such as it is).
>
> http://bnordgren.org/seismo/**T120ZNE.JPG
>
> It gives one of the best illustrations I have seen recently of why we
> prefer verticals for quake watching.  The top trace is the vertical axis
> and the other two are horizontals from the same bedrock-mounted instrument.
>  The quake is difficult to see above the noise on the horizontals though it
> shows up nicely in the vertical channel.  From what I can see of the LA
> weather I think the wind may have been blowing pretty strongly.
>
> Brett
> ______________________________**____________________________
>
> Public Seismic Network Mailing List (PSNLIST)
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> To leave this list email PSNLIST-REQUEST@.............. with the body of
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>
Interesting! But you can definitely see it in the horizont=
als. A high pass filter would bring it out...

---
Dr. Judson L. Ahern
Professor Emeritus,=
 Geophysics

School of Geology & Geophysics
University of Oklahoma
Norman, OK =
73019
jahern@......=A0 =A0=A0 W5JA<=
/div>


On Sun, Oct 6, 2013 at 1:22 PM, Brett No=
rdgren <brett3nt@.............> wrote:

Hi All,



Dave N. has been playing with an old Guralp 24-bit digitizer, attempting to=
 make it work in a predictable manner. =A0Yesterday he hooked it up to his =
Trillium 120 to do some testing and today he recorded a quake that I think =
he said was a 4-something in Mexico, though I don't seem to find it on =
the USGS site (such as it is).




http:=
//bnordgren.org/seismo/T120ZNE.JPG



It gives one of the best illustrations I have seen recently of why we prefe=
r verticals for quake watching. =A0The top trace is the vertical axis and t=
he other two are horizontals from the same bedrock-mounted instrument. =A0T=
he quake is difficult to see above the noise on the horizontals though it s=
hows up nicely in the vertical channel. =A0From what I can see of the LA we=
ather I think the wind may have been blowing pretty strongly.




Brett =A0

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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.