NSF SAGE:
The RESP Format
Data Services
Nodes
DMC
Data
Data Formats
The RESP Format
Requesting Data
Webservices
Web Service Interfaces
Java
API
MATLAB
Library
JWEED
Fetch Scripts
Real time Streaming Service
SeedLink
Email-based requests
BREQ
_FAST
miniSEED
Web-based requests
BUD
Interface
WebRequest
Wilber3
Metadata-only
Dataless
MDA
SeismiQuery
FetchEvent
FetchMetadata
IEB
Status
Submitted requests
Recent shipments
Problems
Re-archiving
Data Problem Reports
The RESP Format
Contents
What is a RESP file?
What are the fields in a RESP file?
Meaning of numbers in rdseed RESP files
Links
What is a
RESP
file?
RESP
file is an
ASCII
representation of
SEED
instrument response information. Generally
RESP
files only contain the subset of
SEED
headers that represent an instrument response, they do not contain station coordinates or other metadata available in
SEED
headers.
SEED
, and consequently
RESP
, can contain comprehensive response details that represent all aspects of the recording of a time series. Each step in the recording process is represented by a stage in the response sequence including analog sensors, digitization and digital filters. A single
RESP
usually contains the response information for a single channel for one or more time ranges (epochs), but a file may also contain the response information for many channels.
RESP
files structure
SEED
response information by rows identifying a
SEED
Blockette and field number followed by its description and value. These readable and easily editable files are commonly used as input to programs that evaluate the response such as evalresp, JEvalResp, and JPlotResp.
How to get
RESP
files (also see the related article below)
The
rdseed
and
PDCC
programs can both generate
RESP
from
SEED
volumes.
RESP
is also available via the
DMC
’s
RESP
webservice
and can be downloaded through the
Nominal Response Library
. Please see related topics for software and access details.
What are the fields in a
RESP
file?
Notes about the meaning of
RESP
files were posted by Sheila Peacock to the sac-help mailing list, which follow.
Meaning of numbers in rdseed
RESP
files
Here is a sample rdseed
RESP
file, which is output if you ask rdseed to output responses:
* RESP.IU.FURI.00.BHE: "RESP" file for FURI component BHE
The topmost part is like this:
# << IRIS SEED Reader, Release 4.6 >>
# ======== CHANNEL RESPONSE DATA ========
B050F03 Station: FURI
B050F16 Network: IU
B052F03 Location: 00
B052F04 Channel: BHE
B052F22 Start date: 1999,111,00:00:00
B052F23 End date: No Ending Time
# =======================================
# + +--------------------------------------------+ +
# + | Response (Poles & Zeros), FURI 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 - Volts
B053F07 A0 normalization factor: 3948.58
B053F08 Normalization frequency: 0.02
B053F09 Number of zeroes: 2
B053F14 Number of poles: 4
# 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 -1.234000E-02 1.234000E-02 0.000000E+00 0.000000E+00
B053F15-18 1 -1.234000E-02 -1.234000E-02 0.000000E+00 0.000000E+00
B053F15-18 2 -3.918000E+01 4.912000E+01 0.000000E+00 0.000000E+00
B053F15-18 3 -3.918000E+01 -4.912000E+01 0.000000E+00 0.000000E+00
# + +---------------------------------------+ +
# + | Channel Gain, FURI ch BHE | +
# + +---------------------------------------+ +
B058F03 Stage sequence number: 1
B058F04 Gain: 2.296000E+03
B058F05 Frequency of gain: 2.000000E-02 HZ
B058F06 Number of calibrations: 0
# + +-------------------------------------------+ +
# + | Response (Coefficients), FURI ch BHE | +
# + +-------------------------------------------+ +
B054F03 Transfer function type: D
B054F04 Stage sequence number: 2
B054F05 Response in units lookup: V - Volts
B054F06 Response out units lookup: COUNTS - Digital Counts
B054F07 Number of numerators: 0
B054F10 Number of denominators: 0
# + +------------------------------+ +
# + | Decimation, FURI ch BHE | +
# + +------------------------------+ +
B057F03 Stage sequence number: 2
B057F04 Input sample rate: 5.120000E+03
B057F05 Decimation factor: 1
B057F06 Decimation offset: 0
B057F07 Estimated delay (seconds): 0.000000E+00
B057F08 Correction applied (seconds): 0.000000E+00
# + +---------------------------------------+ +
# + | Channel Gain, FURI ch BHE | +
# + +---------------------------------------+ +
B058F03 Stage sequence number: 2
B058F04 Gain: 4.194300E+05
B058F05 Frequency of gain: 0.000000E+00 HZ
B058F06 Number of calibrations: 0
And the very end is like this:
# + +---------------------------------------+ +
# + | Channel Sensitivity, FURI ch BHE |
# + +---------------------------------------+ +
B058F03 Stage sequence number: 0
B058F04 Sensitivity: 9.630000E+08
B058F05 Frequency of sensitivity: 2.000000E-02 HZ
B058F06 Number of calibrations: 0
The corresponding poles-zeros file, which is output if you ask rdseed to put it out, is:
ZEROS 3
POLES 4
-0.0123 0.0123
-0.0123 -0.0123
-39.1800 49.1200
-39.1800 -49.1200
CONSTANT 3.802483e+12
The “
RESP
” file represents the velocity response, and hence the poles and zeros listed there include two zeros while the pole-zero file immediately above has three since it represents the displacement response.
The “Sensitivity” at the end of the “
RESP
” file is the product of all the gains in the file (all the numbers in lines containing “Gain”: in this case, 9.63e8 = 2.296e3 V/(m/s) x 4.1943e5 counts/V). It is in the velocity domain and has units of counts per (metre per second) so to convert it to displacement sensitivity (counts per metre) you would
MULTIPLY
by 2pi times the calibration frequency (0.02 Hz in this case). This gives you 10^9 / the value of “calib” that would be found in
GSE
/IMS format files,
CSS
.wfdisc files and “static.instrument”
IDC
database table (8.263497 in this case). “Calib” is in units of nanometres per count.
The number “A0 normalization factor” (value 3948.58 in this case) is said in the
SEED
manual to be “set such that when you evaluate the polynomial at the reference frequency the result will be one”. It is the “poles-and-zeros constant” for the velocity poles-zeros in the “
RESP
” file. If you calculate the poles-zeros constant (a hefty job best done in
FORTRAN
for the complex arithmetic required – beware of floating-point overflow, though!) from the displacement poles-zeros file output by rdseed, rather than take the “
RESP
” file value, you should get the “displacement” poles-and-zeros constant, which is equal to the A0 normalization factor value divided by (2pi times the calibration frequency) (in this case 0.02 Hz, which gives 31421.7).
If you multiply the A0 normalization factor by the “sensitivity” (9.63e8 counts/(m/s)), you get the value of the poles-zeros constant at the end of the poles-zeros file produced by rdseed (3.802483e12 in this case). Note that because this constant consists of the product of a velocity sensitivity (a displacement sensitivity divided by 2pi x calibration frequency) and a velocity poles-zeros constant (a displacement poles-zeros constant multiplied by 2pi x calibration frequency), the factors of 2pi x calibration frequency cancel out and it is correctly a displacement poles-zeros constant (albeit multiplied by the sensitivity) and accompanies a set of displacement poles-zeros, as expected by
SAC
Since the poles-zeros file written by rdseed contains a constant that has already been multiplied by the sensitivity and the sensitivity is equivalent to 1/(calibration factor “calib” in
IDC
parlance x 2pi x frequency), it is not necessary to multiply the seismogram by the calibration factor.
Links
Read about the EarthScope
RESP
Service
Tags
RESP
instrument response
NSF SAGE Facility has been
certified as a trustworthy data repository
by the CoreTrustSeal Standards and Certification Board
Quick Links
Mailing Lists
Frequently Asked Questions
Comments about this page
Directorates
Instrumentation Services
Data Services
Engagement
Connect
EarthScope Consortium operates the
NSF Geodetic Facility for the Advancement of Geoscience (GAGE)
and NSF Seismological Facility for the Advancement of Geoscience (SAGE).
Any opinions, findings and conclusions, or recommendations expressed
in this material do not necessarily reflect the views of the
U.S. National Science Foundation.
09:44:12
v.cd43e7e7