Shear-wave splitting measurements for a 10-year catalogue in Taupō volcano

The dataset provided includes seismic anisotropy results using a 10-year catalogue around Taupō volcano (January 2010  to December 2019). For the seismic anisotropy measurements, we used seismic data from 23 stations managed by GeoNet. The earthquake catalogue for this dataset was determined by Illsley-Kemp et al. (2021) using matched-filtered earthquake detection (Chamberlain & Townend, 2018). The earthquake templates for the matched-filtered detection were obtained from the GeoNet catalogue with revised manual picks. 

In case you use this data, please cite the following publications:

Bakkar, H. (2022). Seismic anisotropy and time-frequency analyses during Taupō's 2019 unrest [Master's thesis, Victoria University of Wellington].

Illsley-Kemp, F., Barker, S. J., Wilson, C. J. N., Chamberlain, C. J., Hreinsd ́ottir, S., Ellis, S., Hamling, I. J., Savage, M. K., Mestel, E. R., & Wadsworth, F. B. (2021). Volcanic unrest at Taupo ̄ volcano in 2019: Causes, mechanisms and implications. Geochemistry, Geophysics, Geosystems, e2021GC009803.

The data is presented in .csv files, in the same format as MFAST output,  (http://mfast-package.geo.vuw.ac.nz), in which each column is:

1. Name of the event.

2. Station code.

3. Station latitude.

4. Station longitude.

5. Event identification number.

6. Year.

7. Julian day on which the event occurred, with decimal digits giving the fraction of the day.

8. Earthquake latitude in degrees.

9. Earthquake longitude in degrees.

10. Distance between earthquake and station (km).

11. Earthquake depth (km).

12. Earthquake magnitude.

13. Back azimuth in degrees.

14. Initial polarisation of the shear wave in degrees.

15. Error of the initial polarisation in degrees, one standard deviation.

16. Start time of the selected measurement window in seconds, relative to the start of the seismogram at t = 0.

17. End time of the selected measurement window in seconds, relative to the start of the seismogram at t = 0.

18. Not used

19. Not used

20. Signal to noise ratio for this event.

21. Delay tome between fast and slow shear wave in seconds.

22. Delay time between fast and slow shear wave in seconds.

23. Angle of the orientation of the fast shear wave (φ), in degrees from North.

24. Error of φ in degrees, one standard deviation.

25. Angle of incidence at the station, measured against a horizontal plane in degrees, where 0 means vertical incidence.

26. Not used

27. Type of measurement. This field contains the measurement code that is used, the number of measurement window start times and the number of window end times.

28. Not used

29. Not used

30. Nyquist frequency of the event in Hz.

31. Evaluation of the measurement quality.

32. Lower corner frequency of the bandpass filter in Hz.

33. Higher corner frequency of the bandpass filter in Hz.

34. Angle between the initial polarisation and the fast orientation in degrees.

35. Not used

36. Not used

37. The maximum value of the eigenvalue of the corrected covariance matrix.

38. The number of degrees of freedom in the measurement.      

39. The minimum value of the eigenvalue of the covariance matrix before it was scaled to have the 95% confidence level set to 1.

40. The S-wave travel time between the earthquake and the station.

41. The dominant frequency in the S wave, determined from the frequency at the maximum spectral amplitude.