[SAC-HELP] Response file confusion

[Tien-Huei Wang]

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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