# EQcorrscan

A Python package for the detection and analysis of repeating and near-repeating seismicity. EQcorrscan contains an efficient, multi-parallel, matched-filter detection routine, as well as routines to implement subspace detection, and detection based on brightness.

Code is stored on github, the development branches are here, or the latest stable release can be found here.

EQcorrscan uses Obspy bindings when reading and writing seismic data, and for handling most of the event metadata, which ensures that detections can be easily migrated between softwares. Matched-filter correlations are calculated using openCV. OpenCV is not installed alongside EQcorrscan and must be installed before using this package.

Also within this package are:

- Clustering routines for seismic data;
- Peak finding algorithm (basic);
- Automatic amplitude picker for local magnitude scale;
- Seisan S-file integration for database management and routine earthquake location;
- Stacking routines including phase-weighted stacking based on Thurber at al. (2014);
- Brightness based template creation based on the work of Frank et al. (2014)

This package is written by Calum Chamberlain and Chet Hopp of Victoria University of Wellington, New Zealand, and is distributed under the LGPL GNU Licence, Copyright Calum Chamberlain & Chet Hopp 2015 & 2016.

## References

- CJ Chamberlain, DR Shelly, J Townend, TA Stern (2014) Low‐frequency earthquakes reveal punctuated slow slip on the deep extent of the Alpine Fault, New Zealand, G-cubed, doi:10.1002/2014GC005436
- Thurber, C. H., Zeng, X., Thomas, A. M., & Audet, P. (2014). Phase‐Weighted Stacking Applied to Low‐Frequency Earthquakes, BSSA, doi:10.1785/0120140077.
- Frank, W. B., & Shapiro, N. M. (2014). Automatic detection of low-frequency earthquakes (LFEs) based on a beamformed network response, Geophysical Journal International, 197(2), 1215-1223, doi:10.1093/gji/ggu058.

## Contents:

- 1. Introduction to the EQcorrscan package
  - 1.1. Why EQcorrscan?
  - 1.2. Installation - Updated for version 0.2.0
  - 1.3. Supported environments
  - 1.4. Functions
  - 1.5. Running tests
- 2. What’s new
  - 2.1. Version 0.1.4
  - 2.2. Version 0.1.3
  - 2.3. Version 0.1.2
  - 2.4. Version 0.1.1
- 3. EQcorrscan tutorials
  - 3.1. Template creation
  - 3.2. Matched-filter detection
  - 3.3. Subspace Detection
  - 3.4. Lag-time and pick correction
  - 3.5. Magnitude calculation
  - 3.6. Clustering and stacking
- 4. Core
  - 4.1. Brightness
  - 4.2. Template generation
  - 4.3. Matched-Filter
  - 4.4. Lag-Calc
  - 4.5. Subspace
  - 4.6. API-docs
- 5. Utils
  - 5.1. archive_read
  - 5.2. catalog_to_dd
  - 5.3. catalog_utils
  - 5.4. clustering
  - 5.5. correlate
  - 5.6. despike
  - 5.7. findpeaks
  - 5.8. mag_calc
  - 5.9. parameters
  - 5.10. picker
  - 5.11. plotting
  - 5.12. pre_processing
  - 5.13. sac_util
  - 5.14. seismo_logs
  - 5.15. sfile_util
  - 5.16. stacking
  - 5.17. synth_seis
  - 5.18. trigger