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.
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.
Dependencies of Qopen are:
- ObsPy>=1.0
- future, NumPy>=1.7, SciPy>=0.11 and matplotlib>=1.3 (itself dependencies of ObsPy)
- statsmodels
- joblib (for multi-core support)
It's probably best to install ObsPy first and then let pip take care of the rest. Install Qopen and its dependencies with
pip install qopen
Qopen provides the two scripts qopen and qopen-runtests. The installation can be tested with the second script:
qopen-runtests
The code is run by the installed command line script qopen. A tutorial can be created with the appropriate flag:
qopen --tutorial
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
qopen
which will calculate the results and create different plots.
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
qopen --create-config
This file has to be adapted to your needs (time window selection, etc.). The inversion is started by simply running qopen again.