Instrument response removal

General Questions
1

Hi, I would appreciate any suggestions on how to remove the instrument response.
I am currently working on plotting velocity ground motion using raw data recorded with a seismometer (CMG-3ESP). I need to remove the instrument response in order to compare it with my simulation. I have 3 components of the record (HHN,HHE, HHZ), as well as information about the seismometer and the values of poles and zeros. Thanks

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2

Hello navids94, and welcome to the community!

As you have a different seismometer model than the ones used with our Raspberry Shakes, I cannot be 100% sure, but I think you can use ObsPy’s seismometer correction and remove response features to achieve what you want. You can find more information here (and, in general, over all their documentation): Seismometer Correction/Simulation — ObsPy 1.4.1 documentation

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3

Hello, Thank you so much for your reply. I used the following code to remove the instrument response but I received an error showing _get_response
raise ValueError(msg)

ValueError: No matching response information found.

code:
from obspy import read, read_inventory
st = read(r"C:\Users\NV\Desktop\New folder\WU.ALFO.20130517.mseed", “MSEED”)
tr = st[0]
inv = read_inventory(r"C:\Users\NV\Desktop\New folder\irisws-nrl_2024-06-12T22_44_48.resp")
pre_filt = [0.1, 5, 45, 50]
output = “VEL”
tr.remove_response(inventory=inv, pre_filt=pre_filt, output=output,
water_level=60, plot=True)

I already have seismic data (mseed) and I downloaded the response file for the seismometer sensor from IRIS.

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4

Hello,

Mmm that kind of error could appear for one of these reasons (you probably have already checked out the first one):

  • Check the response metadata details a second time to ensure that the network, station, location, and channel codes in the MiniSEED file match those in the response file. To verify, you can print out these details from the MiniSEED file and the response file.

  • Also, check that the response file’s time range covers the MiniSEED file’s time range. In this case, I see that the miniSEED appears to be from 2013(?) while the response file is from today, which could create a discrepancy. You should adjust the response file dates accordingly so that there is a match.

  • You can also print out the inventory content to ensure it contains the necessary response information for the specific channel you are working with.

If none of these solve the issue, or there is something wrong with the inventory file/response removal, then you may have to get in touch with IRIS and/or the ObsPy support forum and ask for more information there.

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