hhshiyi / 2020_autocorrelations

Codes to compute autocorrelation functions and reproduce the results of Viens et al. (2022, GJI)

Python codes to compute earthquake and noise autocorrelation functions (ACFs) to image the Kanto Basin, Japan

The codes are for the following manuscript:

• Viens L., C. Jiang, and M. Denolle (2022), Imaging the Kanto Basin seismic basement with earthquake and noise autocorrelation functions, Geophys. J. Int., doi:10.1093/gji/ggac101

Description:

• The Codes folder contains:

  • Compute_AC_PWS.py to compute noise ACFs from the raw MeSO-net data and stack them with the Phase Weighted Stack (PWS, Schimmel and Paulssen, 1997) method (2 days of data at the AYMH station are in the E.AYHM.zip file in the Data folder).
  • Reproduce_Fig_1.py to reproduce Figure 1 (Map of the Kanto Basin, requires Basemap).
  • Reproduce_Fig_3.py to reproduce Figure 3 of the paper (Noise and earthquake ACF plots).
  • Reproduce_Fig_4.py to reproduce Figure 4 of the paper (Maps of the Kanto Basin basin depth, requires Basemap).
  • Reproduce_Fig_8.py to reproduce the Figure 8 of the paper (Axitra simulated ACFs vs observed ACFs).

• The Data folder contains:

  • Five zip files with all the data needed to run the codes and reproduce the figures of the paper. The codes should unzip the zip files automatically.

• The Figures folder contains 10 figures that can be plotted with the 4 codes.

Codes and their outputs:

• The Compute_AC_PWS.py code processes two days of continuous records at the AYMH station and computes the PWS of the 30-min ACFs. For the two days of data, the 20-min ACFs are relatively consistent. Note that we use 1 month of data in the paper.

• The Reproduce_Fig_1.py code outputs a map of the Kanto Basin with the MeSO-net station locations, the JIVSM model, and the four different lines used in this study. The code also plots an azimuthal equidistant projection map centered on the Kanto Basin including all the Mw 6+ earthquakes which occurred within 30 and 95 degrees from the Kanto Basin between May 2017 and 2020.

• The Reproduce_Fig_3.py code is used to plot the noise and earthquake ACFs along the 3 lines. The Figure below shows the ACFs along Line 1.

• The Reproduce_Fig_4.py code compares the bedrock depths from the JIVSM, noise ACF, and earthquake ACF measurements.

• The Reproduce_Fig_8.py code shows a comparison of the Axitra ACF simulations with the observed earthquake and noise ACFs.