Thread: problems rotating components and removing instrument response

Started: 2019-05-17 11:13:12
Last activity: 2019-05-21 09:37:53
Dear,

I have downloaded data from many events. I need to rotate and remove
instrument response of all of them.

1) Some of the events have the components called BH1 and BH2 (or BH2 and
BH3) instead of BHE and BHN. To rotate, I need to know which one is BHE and
which one BHN. For that, I watched the header information looking for
CMPAZ=90 - CMPINC=90 for East component BHE, and CMPAZ=0 - CMPINC=90 for
North component BHN.
The problem was that in some cases the numbers of the CMPAZ were not the
expected ones.
Here I show you just two examples,
Network Station Event BH1 (AZ—INC) BH2 (AZ—INC)
2A 42 2002-11-15-mw66-south-georgia-island-region 0 – 90 0 – 90
IU DWPF 2012-04-14-mw62-drake-passage 311 – 90 41 – 90

2) Another problem appeared when the components BHE and BHN were not an
orthogonal pair so I could not rotate. What shall I do in those cases? Can
I just modify the CMPAZ value to make the pair orthogonal? Or I should look
a solution in another way?
For example:
Network Station Event BHE (AZ) BHN (AZ)
II ASCN 2004-12-22-mw60-southern-east-pacific-rise 93 2
II SUR 2007-11-29-mw63-west-chile-rise 87,4 358,6

3) I had a third problem when I tried to remove the instrument response on
events occurred on 2012 and recorded by the TROLL station (NO network). The
next error message appeared: "*ERROR 2118: No transfer function applied.
Unrecognized Constant: 0.000000 e+00*". I did not know how to fix this.

I wish you could help me. Thank you in advance.
Kind regards,


Geof. Duca Freyre, Leticia
Dpto. de Sismología e Inf. Meteorológica
Facultad de Ciencias Astronómicas y Geofísicas
Universidad Nacional de La Plata
Tel: (+54) 221 4236593, int: 1155

  • Hi Leticia,

    Are you using doing SAC to rotate this data?

    If so please send your question to the sac help mailing list sac-help<at>lists.ds.iris.edu <sac-help<at>lists.ds.iris.edu>.

    Thanks,

    Nick
    --
    Nick Falco
    Web & Apps Developer
    IRIS Data Management Center
    nick<at>iris.washington.edu

    On May 20, 2019, at 1:18 PM, Leticia Duca <leticiaduca<at>gmail.com> wrote:

    Dear,

    I have downloaded data from many events. I need to rotate and remove instrument response of all of them.

    1) Some of the events have the components called BH1 and BH2 (or BH2 and BH3) instead of BHE and BHN. To rotate, I need to know which one is BHE and which one BHN. For that, I watched the header information looking for CMPAZ=90 - CMPINC=90 for East component BHE, and CMPAZ=0 - CMPINC=90 for North component BHN.
    The problem was that in some cases the numbers of the CMPAZ were not the expected ones.
    Here I show you just two examples,
    Network Station Event BH1 (AZ—INC) BH2 (AZ—INC)
    2A 42 2002-11-15-mw66-south-georgia-island-region 0 – 90 0 – 90
    IU DWPF 2012-04-14-mw62-drake-passage 311 – 90 41 – 90

    2) Another problem appeared when the components BHE and BHN were not an orthogonal pair so I could not rotate. What shall I do in those cases? Can I just modify the CMPAZ value to make the pair orthogonal? Or I should look a solution in another way?
    For example:
    Network Station Event BHE (AZ) BHN (AZ)
    II ASCN 2004-12-22-mw60-southern-east-pacific-rise 93 2
    II SUR 2007-11-29-mw63-west-chile-rise 87,4 358,6

    3) I had a third problem when I tried to remove the instrument response on events occurred on 2012 and recorded by the TROLL station (NO network). The next error message appeared: "ERROR 2118: No transfer function applied. Unrecognized Constant: 0.000000 e+00". I did not know how to fix this.

    I wish you could help me. Thank you in advance.
    Kind regards,


    Geof. Duca Freyre, Leticia
    Dpto. de Sismología e Inf. Meteorológica
    Facultad de Ciencias Astronómicas y Geofísicas
    Universidad Nacional de La Plata
    Tel: (+54) 221 4236593, int: 1155






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