[SAC-HELP] Response file confusion

[Rick Benson]

Hi, Tien-Huei-
 The first thing to notice is that the time periods (epochs in SEED lingo)
are different, suggesting that these are indeed different sensors,
dataloggers, or other response characteristics.
 You need to make sure that the information is correlated by time as well.
 Hope this helps-
 Rick

On Mar 14, 2012, at 11:57 AM, Tien-Huei Wang wrote:

> Hi all,
>     I 've been using broadband data from IRIS on research and recently encounter a confusing thing about response.
> I am using the BH* channels of network AZ, and it should be velocity data. I downloaded sac files from SCEC stp.
> I originally request response file in SEED format, then extracted it to be RESP.AZ.XXX..BHX, the response file. 
> Recently, because I want to confirm the amplitudes in velocity and also in displacement is correct, I went to IRIS SeismiQuery to get the response file updated until 2011. Surprisingly, the extracted response file from my SEED format and the response file from SeismiQuery are different.
> The RDSEED extracted response file has 2 zeros and 5 poles, but the response file from SeismiQuery has 5 zeros 9 poles.
> I thought 2 zeros is standard for velocity response, had no idea what the 5 zeros are. They are from the same time span for same station. 
> 
> Post front portion of RESP files
> 1. from RDSEED:
> =================================
> #               << IRIS SEED Reader, Release 4.7.5 >>
> #               
> #               ======== CHANNEL RESPONSE DATA ========
> B050F03     Station:     RDM
> B050F16     Network:     AZ
> B052F03     Location:    ??
> B052F04     Channel:     BHE
> B052F22     Start date:  2004,056,18:43:30
> B052F23     End date:    No Ending Time
> #               =======================================
> #               +               +--------------------------------------------+                +
> #               +               |   Response (Poles & Zeros),   RDM ch BHE   |                +
> #               +               +--------------------------------------------+                +
> #               
> B053F03     Transfer function type:                A [Laplace Transform (Rad/sec)]
> B053F04     Stage sequence number:                 1
> B053F05     Response in units lookup:              M/S - velocity in meters per second
> B053F06     Response out units lookup:             V - emf in volts
> B053F07     A0 normalization factor:               5.91892E+07
> B053F08     Normalization frequency:               0.159155
> B053F09     Number of zeroes:                      2
> B053F14     Number of poles:                       5
> #               Complex zeroes:
> #                 i  real          imag          real_error    imag_error
> B053F10-13    0  0.000000E+00  0.000000E+00  0.000000E+00  0.000000E+00
> B053F10-13    1  0.000000E+00  0.000000E+00  0.000000E+00  0.000000E+00
> #               Complex poles:
> #                 i  real          imag          real_error    imag_error
> B053F15-18    0 -3.701000E-02  3.701000E-02  0.000000E+00  0.000000E+00
> B053F15-18    1 -3.701000E-02 -3.701000E-02  0.000000E+00  0.000000E+00
> B053F15-18    2 -2.513000E+02  0.000000E+00  0.000000E+00  0.000000E+00
> B053F15-18    3 -1.310000E+02  4.673000E+02  0.000000E+00  0.000000E+00
> B053F15-18    4 -1.310000E+02 -4.673000E+02  0.000000E+00  0.000000E+00
> 
> 
> 2. from SeismiQuery
> ======================================
> 
> ###################################################################################
> #
> B050F03     Station:     RDM
> B050F16     Network:     AZ
> B052F03     Location:    ??
> B052F04     Channel:     BHE
> B052F22     Start date:  2000,264,20:11:00
> B052F23     End date:    2001,250,20:49:00
> #
> #                  +-----------------------------------+
> #                  |    Response (Poles and Zeros)     |
> #                  |        AZ  RDM        BHE         |
> #                  |     09/20/2000 to 09/07/2001      |
> #                  +-----------------------------------+
> #
> B053F03     Transfer function type:                A
> B053F04     Stage sequence number:                 1
> B053F05     Response in units lookup:              M/S - velocity in meters per second
> B053F06     Response out units lookup:             V - emf in volts
> B053F07     A0 normalization factor:               +5.74357E+12
> B053F08     Normalization frequency:               +2.00000E-01
> B053F09     Number of zeroes:                      5
> B053F14     Number of poles:                       9
> #              Complex zeroes:
> #              i  real          imag          real_error    imag_error
> B053F10-13     0  +0.00000E+00  +0.00000E+00  +0.00000E+00  +0.00000E+00
> B053F10-13     1  +0.00000E+00  +0.00000E+00  +0.00000E+00  +0.00000E+00
> B053F10-13     2  -1.51500E+01  +0.00000E+00  +0.00000E+00  +0.00000E+00
> B053F10-13     3  -3.18600E+02  +4.01200E+02  +0.00000E+00  +0.00000E+00
> B053F10-13     4  -3.18600E+02  -4.01200E+02  +0.00000E+00  +0.00000E+00
> #              Complex poles:
> #              i  real          imag          real_error    imag_error
> B053F15-18     0  -3.70000E-02  +3.70000E-02  +0.00000E+00  +0.00000E+00
> B053F15-18     1  -3.70000E-02  -3.70000E-02  +0.00000E+00  +0.00000E+00
> B053F15-18     2  -1.59900E+01  +0.00000E+00  +0.00000E+00  +0.00000E+00
> ...
> 
> 
> Does anyone know why and how this will affect our final outcome? What are the outputs and will they be consistent?
> 
> Thanks,
> 
> --Tien
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================
Rick Benson
Director of Data Management
IRIS DMC
(206)547-0393 ext. 119(office)
rick at iris.washington.edu



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