Thread: DECONVOLUTION WITH SAC

Started: 2017-03-02 06:06:24
Last activity: 2017-03-02 17:28:20
Topics: SAC Help
Andrea Pérez
DECONVOLUTION WITH SAC
2017-03-02 06:06:24
Hello. I'm trying to run a deconvolution of a real seismogram to remove the instrument response, introducing the file that contains the real seismogram (which has an ascii format) and the response of the instrument (a REF TEK RT151B-30) which I found on the IRIS website: "http://ds.iris.edu/NRL/sensors/reftek/reftek_rt151_sensors.html" as a RESP file. I have been trying to accomplish it, but haven't been able to, even though I follow the steps as the manual indicates. I may be doing something wrong, therefore I am asking for your advice on the matter. Please.

These are the commands I have introduced:

SAC> SETBB RESP "RESP.XX.NS360..BHZ.RT151B.30.2000"
SAC> READTABLE 201605100605L.asc
SAC> WRITE SAC 20160510065L
SAC> READ 20160510065L
SAC> RTR
SAC> TAPER
SAC> TRANSFER FROM EVALRESP FNAME RESP.XX.NS360..BHZ.RT151B.30.2000 TO VEL

And this is the response I get:

Using response from user-specified file: (RESP.XX.NS360..BHZ.RT151B.30.2000).
Extracting evresp response for *, *...
Station (-12345 ), Channel (-12345 )

Then I plot the results and the seismogram obtained contains velocity values too high, I've tried many times to run it, but I get the same results, and I can't identify what the issue is, I may be doing something wrong, I hope you can help me, thank you so much.

Best Regards
Andrea.

  • Milton Plasencia
    Re: DECONVOLUTION WITH SAC
    2017-03-02 00:17:43
    Hi Andrea,

    Perhaps you need add the freqlimit option in transfer command,
    There is more answer in this topic in the sac list.

    If not please, attach you files (ascii+RESP files) in order to help you.

    Cheers,

    Milton




    On Mar 1, 2017, at 16:08, Andrea Pérez @iris.washington.edu <andreasarai5<at>outlook.com> wrote:

    Hello. I'm trying to run a deconvolution of a real seismogram to remove the instrument response, introducing the file that contains the real seismogram (which has an ascii format) and the response of the instrument (a REF TEK RT151B-30) which I found on the IRIS website: "http://ds.iris.edu/NRL/sensors/reftek/reftek_rt151_sensors.html" as a RESP file. I have been trying to accomplish it, but haven't been able to, even though I follow the steps as the manual indicates. I may be doing something wrong, therefore I am asking for your advice on the matter. Please.

    These are the commands I have introduced:

    SAC> SETBB RESP "RESP.XX.NS360..BHZ.RT151B.30.2000"
    SAC> READTABLE 201605100605L.asc
    SAC> WRITE SAC 20160510065L
    SAC> READ 20160510065L
    SAC> RTR
    SAC> TAPER
    SAC> TRANSFER FROM EVALRESP FNAME RESP.XX.NS360..BHZ.RT151B.30.2000 TO VEL

    And this is the response I get:

    Using response from user-specified file: (RESP.XX.NS360..BHZ.RT151B.30.2000).
    Extracting evresp response for *, *...
    Station (-12345 ), Channel (-12345 )

    Then I plot the results and the seismogram obtained contains velocity values too high, I've tried many times to run it, but I get the same results, and I can't identify what the issue is, I may be doing something wrong, I hope you can help me, thank you so much.

    Best Regards
    Andrea.

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    • Robert Casey
      Re: DECONVOLUTION WITH SAC
      2017-03-02 17:28:20

      The NRL Tool in PDCC appends an NRL datalogger selection to the NRL Sensor selection by replacing the stage 2 through N entries in the RESP file with the datalogger response. Nothing is changed in terms of the indicated system's passband for sensitivity, but in many cases this is not an issue. PDCC then runs this modified RESP stack through evalresp to get the new sensitivity. Wen-Tzong is correct that you want to also select the NRL Datalogger for your installation.

      -Rob



      On Mar 2, 2017, at 1:45 AM, Wen-Tzong Liang <wtl<at>earth.sinica.edu.tw> wrote:

      That nominal response file contains only information of seismometer. You need also the conversion factor of your datalogger to recover the true ground motion.

      ----------------------
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      Sent from the IRIS Message Center (http://ds.iris.edu/message-center/)
      Update subscription preferences at http://ds.iris.edu/account/profile/


      On Mar 1, 2017, at 2:17 PM, Milton Plasencia <mpplasencia<at>gmail.com> wrote:

      Hi Andrea,

      Perhaps you need add the freqlimit option in transfer command,
      There is more answer in this topic in the sac list.

      If not please, attach you files (ascii+RESP files) in order to help you.

      Cheers,

      Milton




      On Mar 1, 2017, at 16:08, Andrea Pérez @iris.washington.edu <andreasarai5<at>outlook.com <andreasarai5<at>outlook.com>> wrote:

      Hello. I'm trying to run a deconvolution of a real seismogram to remove the instrument response, introducing the file that contains the real seismogram (which has an ascii format) and the response of the instrument (a REF TEK RT151B-30) which I found on the IRIS website: "http://ds.iris.edu/NRL/sensors/reftek/reftek_rt151_sensors.html" as a RESP file. I have been trying to accomplish it, but haven't been able to, even though I follow the steps as the manual indicates. I may be doing something wrong, therefore I am asking for your advice on the matter. Please.

      These are the commands I have introduced:

      SAC> SETBB RESP "RESP.XX.NS360..BHZ.RT151B.30.2000"
      SAC> READTABLE 201605100605L.asc
      SAC> WRITE SAC 20160510065L
      SAC> READ 20160510065L
      SAC> RTR
      SAC> TAPER
      SAC> TRANSFER FROM EVALRESP FNAME RESP.XX.NS360..BHZ.RT151B.30.2000 TO VEL

      And this is the response I get:

      Using response from user-specified file: (RESP.XX.NS360..BHZ.RT151B.30.2000).
      Extracting evresp response for *, *...
      Station (-12345 ), Channel (-12345 )

      Then I plot the results and the seismogram obtained contains velocity values too high, I've tried many times to run it, but I get the same results, and I can't identify what the issue is, I may be doing something wrong, I hope you can help me, thank you so much.

      Best Regards
      Andrea.

      ----------------------
      SAC Help (http://ds.iris.edu/message-center/topic/sac-help/)

      Sent from the IRIS Message Center (http://ds.iris.edu/message-center/)
      Update subscription preferences at http://ds.iris.edu/account/profile/

      ----------------------
      SAC Help (http://ds.iris.edu/message-center/topic/sac-help/)

      Sent from the IRIS Message Center (http://ds.iris.edu/message-center/)
      Update subscription preferences at http://ds.iris.edu/account/profile/


  • Wen-Tzong Liang
    Re: DECONVOLUTION WITH SAC
    2017-03-02 09:45:09
    That nominal response file contains only information of seismometer. You need also the conversion factor of your datalogger to recover the true ground motion.
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