OBS Orientations

We have developed a Python-based software package to estimate the geographic orientation of the horizontal componenets of broadband three-component seismometers. The codes were originally written to orient free-fall ocean-bottom seismometers (OBS), but can also be used with land stations, including those from the GSN or USArray.

The codes are available free of charge, and are licensed under the Simplified BSD License.
For more information regarding the method, implementation, or results, please see:

Doran, A. K., and G. Laske (2017). Ocean-bottom seismometer instrument orientations via automated Rayleigh-wave arrival-angle measurements, Bulletin of the Seismological Society of America, 107(2), doi:10.1785/0120160165.

Please site this publication if you use our results or software.


Download:
DLOPy_v1.0.zip

This is a zipped folder containing the necessary Python routines, along with documentation discussing the installation and usage of the program.

In its current form, DLOPy relies on the Python package ObsPy for data retrieval. More information and installation help can be found in the DLOPy README or at https://github.com/obspy/obspy/wiki.

If you have any questions or comments, or discover any bugs, please email me at adoran at ucsd dot edu.


Results

We provide instrument orientations for two networks of OBSs as part of our original analysis.

Table 1 contains results from the Cascadia Initiative was a multi-year deployment of hundreds of OBS packages offshore the northwest US (more information at http://cascadia.uoregon.edu).

Table 2 contains results from the three Ocean Seismic Network Pilot Experiment (Collins et al, 2001, GRL; Stephen et al, 2004, G3) sensors and the OBSs from the second phase of the PLUME deployment (https://igppweb.ucsd.edu/~gabi/plume.html). As described in Doran and Laske (2017), our results for the seven SIO instruments of PLUME2 are 180 degrees off from the previously published results of Rychert et al (2013). We have not yet identified the source of this error. One possibility is that the channel names were flipped and data re-uploaded to the IRIS DMC after the previous orientation estimates but before our most recent. Table 2 also contains the STACHPy results (computed using the method of Stachnik et al (2012) and the Laske et al (1994) results used in the Rychert et al paper.