Removing Instrumental Response

[lukemilner]

Hi Marc,

I am using ambient data recorded by the British Geological Survey (BGS) in MiniSEED format, available online via the following link:

http://earthquakes.bgs.ac.uk/monitoring ... chive.html

I am trying to deconvolve the instrument response- so I have a more scientific unit (i.e displacement or velocity or acceleration) vs time, as opposed to the present 'instrumental counts' against time.

I see there is an option for removing the instrumental response within geopsy, but I am not sure how to carry this out with my data. Is this possible?

I should add that the response files required to transform the data into meaningful units are also provided on the website in SEED format.

I've attached an example BGS trace here (Data_file.txt) , along with the corresponding instrument response file (Instrument_Response.txt)

Many thanks,

Luke

[lyegres]

Hi Luke,

I saw your query and I am wandering if you managed to solve the instrument response correction. I know that the latest versions of geopsy have the option in waform tools as "remove instrument response". My question comes when trying to load the resp file, it asks for a "*.sensor" format. Thank you in advanced.

Best regards,

Luis

[admin]

Hi,

The pole and zeros can be entered in the instrumental response GUI box. Export as a .sensor file. These are compressed tar file with an XML format.

Here is an example for Lennartz 5 seconds sensors:

Code: Select all

<InstrumentalResponse>
  <name>Lennartz 5s</name>
  <transductionFactor>400</transductionFactor>
  <normalizationFactor>1</normalizationFactor>
  <frequencyFactor>6.283185307179586232</frequencyFactor>
  <noiseLevel>1.0000000000000000209e-8</noiseLevel>
  <pole>-0.888 0.888</pole>
  <pole>-0.888 -0.888</pole>
  <pole>-0.29 0</pole>
  <zero>0 0</zero>
  <zero>0 0</zero>
  <zero>0 0</zero>
</InstrumentalResponse>

[lyegres]

Thank you very much for your help and example!

Best regards

[lega]

Hi!

I am also trying to perform instrument response removal of data in miniseed format.
I can input poles and zeroes from manufacturer technical specs as shown below.

Sample pic.png

(118.22 KiB) Not downloaded yet

I just have several questions regarding the sample xml file of the Lennartz 5s sensor and other input values:

1. is the transduction factor (V/m/s) the same as "sensitivity (counts/m/s)"?
2. is the normalization factor the same as decimation factor?
3. is the noise level the same as minimum detection threshold?

I have a template instrument response in xml.

out4.response (1).txt

(7.84 KiB) Downloaded 2194 times

Thank you so much!
PS. I'm new to instrument response removal. Thank you for your patience

[Morphiner]

Hi Marc,

I am not sure if there is an answer and solution to my problem, but here it is:

I also want to remove the instrument response to perform some ratios between rock earthquake data and noise data. I am using a MiniShark with Lennarz 5s. KEAS (former LEAS) has no clue to provide any information about the digitizer, they directed me to you.

My problem is that even if I do manage to get any info about the Shark, I am using variable gains depending on position and level of noise, so I will have to have multiple .sensor files and use every time the appropriate one. Am I wrong?

Unless by using only the poles and zeroes for the Lennarz will give me velocity values. What do you think?

Best,
Ilias