International Federation of Digital Seismograph Networks

Thread: Re: FDSN Working Group I draft agenda

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Started: 2019-07-02 17:47:48
Last activity: 2019-07-02 17:47:48
Wen-Tzong Liang
2019-07-02 17:47:48
Dear Rudolf,

Thanks for the plot. I am impressed with the superb low noise level of BFO.

Best regards,
Wen-Tzong

-----Original message-----
From:Rudolf Widmer-Schnidrig <widmer<at>gis.uni-stuttgart.de>
To:wtl <wtl<at>earth.sinica.edu.tw>,FDSN Working Group I <fdsn-wg1-stations<at>lists.fdsn.org>
Cc:Pete Davis <Pdavis<at>ucsd.edu>,Thomas Forbriger <Thomas.Forbriger<at>kit.edu>,Kutterer,Hansjörg (GIK) <Hansjoerg.kutterer<at>kit.edu>
Date:Tue, 02 Jul 2019 17:37:55
Subject:Re: [fdsn-wg1-stations] FDSN Working Group I draft agenda


Dear Wen-Tzong,

the quality of BFO shows best in the band 200 - 3000 seconds.
This is the band of the Earth's free oscillations and it is outside the
frequency band covered by your plots.

The contribution of BFO STS-1 data to the GSN low-noise model of Berger
et al. (2004) is illustrated in the attached plot.
The plot shows that there are several bands where the STS-1 seismometer
at BFO - both vertical and horizontal - helps to define the vertical and
horizontal GSN low-noise model.

Unfortunately I cannot come to IUGG but I imagine that there are plenty
of people in WG1 that know BFO.

           kind regards,

                                            Rudolf Widmer-Schnidrig





Am 02.07.19 um 11:11 schrieb wtl:
Dear Rudolf,

As shown in the attached image files, BFO's noise level (mode value in blue color) is pretty low compared to the rest of 139 FDSN stations (gray lines). Personally I love the performance of BFO station.

_06.jpg: June of 2018
_12.jpg: December of 2018

We can figure out criteria for selecting potential new FDSN stations during the WG-1 meeting. Are you coming for the IUGG meeting this year?

Wen-Tzong


-----Original message-----
From:Rudolf Widmer-Schnidrig <widmer<at>gis.uni-stuttgart.de>
To:Wen-Tzong Liang <wtl<at>earth.sinica.edu.tw>
Cc:Pete Davis <Pdavis<at>ucsd.edu>,Thomas Forbriger <Thomas.Forbriger<at>kit.edu>,Kutterer,Hansjörg (GIK) <Hansjoerg.kutterer<at>kit.edu>
Date:Wed, 26 Jun 2019 23:30:17
Subject:Re: [fdsn-wg1-stations] [fdsn-wg1-stations] FDSN Working Group I draft agenda

Dear Wen-Tzong,

I would like to propose to include BFO, an affiliated IRIS/IDA station,
in the group of FDSN backbone stations.

As argument for including BFO in this group of stations I would put
forward the very low noise level in
the frequency band of the Earth's free oscillations.
See for example the ranking of BFO in the near real-time noise plots of
Goran Ekstrom (Lamont)

https://www.ldeo.columbia.edu/~ekstrom/Research/Noise/RADB_hourly_rms.html

Discoveries made based on BFO data include:

          Horizontal Hum   (Kurrle & Widmer-Schnidrig, GRL, 2008)
          Observation of Coriolis coupled modes below 1mHz (Zuern et
al., GJI, 2000)
          On noise reduction in vertical seismic records below 2 mHz
using local
                   barometric pressure (Zuern & Widmer, GRL, 1995)
               This last paper was at the start of installing
barometers at GSN stations.

I cc this mail to Pete Davis (IRIS/IDA) as he knows BFO very well too.

                     Sincerely,

Rudolf Widmer-Schnidrig, BFO



Am 25.06.19 um 19:39 schrieb Wen-Tzong Liang:
Dear FDSN WG I members,

The FDSN Working Group I on Station Siting and Instrumentation will be held on Friday, July 12, 2019 in Room 513D of the Montreal Convention Center from 12:00 to 13:30.

The draft agenda for the WG I meeting is listed below:

12:00 Review and Approval of the 2017 Minutes from Kobe
Please see http://www.fdsn.org/media/wg/I/2017/FDSNWG1.ppt

12:05 Review of the Definition of the FDSN Backbone Stations

Please see http://www.fdsn.org/media/wg/I/2009/2009_FDSN_WG1_minutes.pdf
and http://www.fdsn.org/media/wg/I/2017/FDSNWG1.ppt for details.

A tentative statement is proposed below, which will be discussed during the meeting:
"A subset of 250 (need more?) stations chosen on the basis of hardware standards (VBB or BB and VLP, 3-component, dynamic range greater than 100db), noise characteristics, geographical location, and status (installed or installation imminent)."

The current _FDSN backbone stations can be found at
http://www.iris.edu/mda/_FDSN or http://www.iris.edu/gmap/_FDSN
(Note that 38 stations there are not available Right Now.)

12:35 Replacement of the FDSN station inventory which was maintained in an excel file.

12:50 A quick report of the performance of the FDSN backbone stations
(Do we need to increase the number of FDSN backbone stations? If yes, how many?)

13:20 Other business

13:30 Adjourn

If there are any items you think we should discuss in the meeting as well, please just let me know that.

See you soon,
Wen-Tzong
-------------------------------
Wen-Tzong Liang
Chair of FDSN WG1
Institute of Earth Sciences, Academia Sinica, Taiwan
http://bats.earth.sinica.edu.tw
http://tec.earth.sinica.edu.tw

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--
+---------------------------------------------------------------+
Rudolf Widmer-Schnidrig
Black Forest Observatory (BFO)
Heubach 206
D-77709 Wolfach, Germany
e-mail: widmer<at>gis.uni-stuttgart.de
phone: +49 7836 2151
fax: +49 7836 955240
48d 19' 48.24" North 8d 19' 23.13" East

+---------------------------------------------------------------+