Characteristics on Bode plot using Inventory.plot_response

Dear people of ObsPy,

where can I find some details (documentation) about 2 highlighted numbers on
Bode plot using Inventory.plot_response (see [1])?

* Right value shows plateau of amplitudes -- it's clear for me;
in [1]: 9.4e+08.
* But top value (in [1]: 0.02Hz = 50s) often don't show expected flat regions
lower corner frequency. Without knowledge of example's details I would expect
in case [1] something around 0.01Hz = 100s (probably 120s = STS2?). At least
one of my STS2-plots shows exactly the same unexpected value.

In my examples in 6 of 7 cases highlighted frequency don't match lower corner,
but in one case it fits well. So it could be possible that I'm wrong to expect
lower corner frequency for highlighting - but what else frequency could be
highlighted otherwise?

Best Regards


Sfunke.vcf (168 Bytes)

Hi Sigward,

the values you see as annotations to the amplitude spectrum in the Bode
plot are simply what is specified for the overall sensitivity in the
given station metadata:

from obspy import read_inventory
response = read_inventory()[0][0][0].response

Instrument Sensitivity:
  Value: 943680000.0
  Frequency: 0.02
  Input units: M/S
  Input units description: Velocity in Meters per Second
  Output units: COUNTS
  Output units description: Digital Counts

Usually this should be within the flat part of the response.


Hi Tobias,

thanks for fast and clear explanation. So not corner frequency is annotated
but frequency of overall sensitivity - makes sense.

Best Regards