Ppol¶
Ppol – short for P-wave polarization – is a Python package based on ObsPy.
Its purpose is to determine (mis-)orientations of the horizontal components of ocean-bottom seismometers (OBS).
It is equally applicable to terrestrial seismometers.
To retrieve these horizontal sensor orientations, ppol uses earthquake information and compares expected (theoretical) backazimuth angles with those calculated from earthquake
P-wave arrivals contained in your waveform data (using 2-D and/or 3-D principle component analysis).
The package is further capable to improve on the calculated station orientations by fitting for seismic anisotropies and dipping discontinuities beneath the station.
The code is based on the following, peer-reviewed paper. If you find ppol useful, please consider citing it. :)
Scholz, John-Robert, Guilhem Barruol, Fabrice R. Fontaine, Karin Sigloch, Wayne Crawford, and Martha Deen. “Orienting Ocean-Bottom Seismometers from P-Wave and Rayleigh Wave Polarisations.” Geophysical Journal International 208, no. 3 (2017): 1277–1289. https://doi.org/10.1093/gji/ggw426.