Separation of intrinsic and scattering Q by envelope inversion
Qopen is a script in seismology that estimates shear wave scattering and intrinsic attenuation parameters by inversion of seismogram envelopes.
How it works
The method is described in the following publication:
Tom Eulenfeld and Ulrich Wegler (2016), Measurement of intrinsic and scattering attenuation of shear waves in two sedimentary basins and comparison to crystalline sites in Germany, Geophysical Journal International, 205(2), 744-757, doi:10.1093/gji/ggw035. [pdf]
Alternatively, have a look at our poster presented at the 2015 Annual Meeting of the DGG.
How to use it
Since version 2, Qopen runs on Python3 only. If you want to use Qopen with Python2 use version 1.x.
Dependencies of Qopen are:
- NumPy, SciPy and matplotlib (itself dependencies of ObsPy)
- statsmodels, joblib
Installation with conda :: It's probably best to install ObsPy first and then let pip take care of the rest. Install Qopen and its dependencies with
conda --add channels conda-forge conda create -n qopen python=3 obspy statsmodels source activate qopen pip install qopen
Qopen provides the scripts qopen, qopen-rt and qopen-runtests. The installation can be tested with the second script:
The code is run by the installed command line script qopen. A tutorial can be created with the appropriate flag:
This command copies an example configuration file in JSON format and the corresponding data files into the current directory. The configuration file is heavily commented and should be rather self-explanatory. Now you can perform the inversion by simply running
which will calculate the results and create different plots.
Use your own data
To use the script with your own data you need 1. an inventory (StationXML or other ObsPy readable format) of your stations, 2. the earthquake catalog (QuakeML or other ObsPy readable format) preferable with P and S picks and 3. the waveforms. Waveforms may exist in data files of various formats or can be fetched from a webservice. A custom solution for waveform retrieval is also possible (e.g. mixing of data files and web requests). An example configuration file can be created with
This file has to be adapted to your needs (time window selection, etc.). The inversion is started by simply running qopen again.
Use Qopen in Python scripts
To call Qopen from Python do e.g.
from qopen import run run(conf='conf.json')
All configuration options in conf.json can be overwritten by keyword arguments passed to run().
Please also consult the API documentation.
Get help and discuss
The seistools mailing list can be used to contact other users and developers.
A somewhat advanced example using the Qopen package: USAttenuation.