statphase2slowvec.py
Release v1.0.0 from October 13, 2022, is archived under
https://zenodo.org/record/7195885#.Y0rf0UxBxaQ with DOI 10.5281/zenodo.7195885
https://doi.org/10.5281/zenodo.7195885
Licenced under the EUPL (European Union Public Licence)
https://joinup.ec.europa.eu/collection/eupl/eupl-text-eupl-12
Steven J Gibbbons
June 14, 2021 (NGI)
Needs os, sys, argparse, numpy, geographiclib, math, obspy
Single standalone python code which takes a single ASCII file of the format
Station_Name Phase_Name Station_Lat Station_Lon
together with a reference coordinate for the source, and it will write out a file containing the corresponding lines
Station_Name Phase_Name Station_Lat Station_Lon Ref_Lat Ref_Lon Sx_outgoing Sy_outgoing
where Sx and Sy are the East-West and the North-South horizontal slowness vectors at the
seismic source given by Ref_Lat Ref_Lon with units (s/km) with respect to the AK135 model
(Kennett et al., 1995).
For example, we consider the Hukkakero explosion site in Northern Finland (see Gibbons et al., 2020).
We use the reference coordinates
latitude 67.93590 and longitude 25.83491.
We want to calculate the slowness vectors for the outgoing wavefront for the first arriving regional P phase and the first arriving regional S phase for the 6 stations used by the study Gibbons et al. (2020).
So our input file is as follows:
ARE0 P1 69.53490 25.50580
ARE0 S1 69.53490 25.50580
KEV P1 69.75530 27.00670
KEV S1 69.75530 27.00670
SGF P1 67.44211 26.52611
SGF S1 67.44211 26.52611
LP34 P1 67.26574 28.12528
LP34 S1 67.26574 28.12528
LP53 P1 68.08434 27.18877
LP53 S1 68.08434 27.18877
LP61 P1 67.91408 23.93216
LP61 S1 67.91408 23.93216
(call it, for example Finland_phaselist.txt).
If we call the program as follows:
python ../statphase2slowvec.py \
--reflat 67.93590 \
--reflon 25.83491 \
--phaselistfile Finland_phaselist.txt \
--outfile Finland_ak135_slovecs.txt
then this should generate the following ASCII file:
ARE0 P1 69.53490 25.50580 67.93590 25.83491 -0.00888570 0.12337091
ARE0 S1 69.53490 25.50580 67.93590 25.83491 -0.01594664 0.22140645
KEV P1 69.75530 27.00670 67.93590 25.83491 0.02687697 0.12073203
KEV S1 69.75530 27.00670 67.93590 25.83491 0.04823417 0.21666916
SGF P1 67.44211 26.52611 67.93590 25.83491 0.08181667 -0.15176232
SGF S1 67.44211 26.52611 67.93590 25.83491 0.13714934 -0.25439928
LP34 P1 67.26574 28.12528 67.93590 25.83491 0.13871543 -0.10238026
LP34 S1 67.26574 28.12528 67.93590 25.83491 0.23252879 -0.17162010
LP53 P1 68.08434 27.18877 67.93590 25.83491 0.16493699 0.05021592
LP53 S1 68.08434 27.18877 67.93590 25.83491 0.27648398 0.08417697
LP61 P1 67.91408 23.93216 67.93590 25.83491 -0.17239066 -0.00260066
LP61 S1 67.91408 23.93216 67.93590 25.83491 -0.28897858 -0.00435949
(with the name Finland_ak135_slovecs.txt)
#References
Gibbons, S.J., Kvaerna, T., Tiira, T., Kozlovskaya, E., 2020.
A benchmark case study for seismic event relative location,
Geophys J Int, 223, 1313-1326
https://doi.org/10.1093/gji/ggaa362
Kennett, B.L.N. Engdahl, E.R. & Buland R., 1995.
Constraints on seismic velocities in the Earth from travel times,
Geophys J Int, 122, 108-124
https://doi.org/10.1111/j.1365-246X.1995.tb03540.x