orient

The orient is a package written in MATLAB, developed for determining the orientation of ocean bottom seismograph (OBS) via Rayleigh-wave polarization.

This package calculate the orientation based on the method of Stachnik et al. (2012).

<div align=center><img src="FIGURES/orient.png" width="350"/></div>

Authors

Ba Manh Le & Yuechu Wu

Chinese introduction

被动源OBS数据处理（3）：确定OBS水平方位角

Data

• Public seismic data can be downloaded by using package DownloadSeisData.
• The user's own data file is also supported. The first 15 digits of the event file name should preferably be yyyymmdd_HHMMSS (e.g., 20120827_043719, represents 2012-08-27T04:37:19). The earthquake event data storage path is shown in the figure below.

<div align=center><img src="FIGURES/sacdata_event_path.png" width="650"/></div>

Usage

Note: The quality of seismic event data determines the accuracy and error range of the results.

• Usage 1 (automatic)

1. Run orient, the script will automatically select the event data and calculate the orientation.

• Usage 2 (manual)

1. Run plot_waveform, the script will roughly select the events and plot the waveforms.
2. Enter the waveform figure folder and delete the figures with poor quality (select events manually).
3. Run orient_select, the script will calculate the orientation based on the selected events.

Example results

• Automatically select events

<div align=center><img src="FIGURES/north.png" width="500"/></div> <div align=center><img src="FIGURES/rose.png" width="500"/></div>

• Manually select events

<div align=center><img src="FIGURES/north_select.png" width="500"/></div> <div align=center><img src="FIGURES/rose_select.png" width="500"/></div>

Cite

If you use orient in your work, please cite:

Yuechu Wu, Ting Yang, Min Xu, Dan Liu, Yizhi Wang, Chuanhai Yu, Mei Xue, Weiwei Ding, Baohua Liu. (2024). A passive‐source ocean‐bottom seismic experiment in the South China Sea: Evaluations of data quality and instrument performance. Seismological Research Letters, https://doi.org/10.1785/0220240224

References

• Stachnik, J. C., Sheehan, A. F., Zietlow, D. W., Yang, Z., Collins, J., Ferris, A. (2012) Determination of New Zealand Ocean Bottom Seismometer Orientation via Rayleigh-Wave Polarization. Seismological Research Letters, 83(4): 704–713. https://doi.org/10.1785/0220110128