Vp/Vs

Calculate Vp/Vs ratio using differential times from waveform cross-correlation.

Input

• .mat file that contains CC times for pairs of events

  Format:

EVENT ID | EVENT ID | CC (correlation coefficient) | DT (delay time) |
STATION NUMBER (instead of using characters) | Phase ID [1: P, 2: S]

• Catalog file with clusters
• Format:

 YEAR ORIGINTIME | LATITUDE | LONGITUDE| DEPTH | MAGNITUDE| DECIMAL YEAR |
 TIME RALTIVE TO THE FIRST EVENT IN THE CATALOG| EVENT ID| CLUSTER ID

Note:

The input file can be obtain after using xcorr.

cc=cell2mat(cut_event_pairs);
save results_xcorr.mat

This code is based on

Lin, G., & Shearer, P. (2007). Estimating local Vp/Vs ratios within similar earthquake clusters. Bulletin of the Seismological Society of America, 97(2), 379–388. https://doi.org/10.1785/0120060115

Bachura, M., & Fischer, T. (2016). Detailed velocity ratio mapping during the aftershock sequence as a tool to monitor the fluid activity within the fault plane. Earth and Planetary Science Letters, 453(1975), 215–222. https://doi.org/10.1016/j.epsl.2016.08.017

and was used in

Maria Mesimeri, Athanassios Ganas, Kristine L Pankow, Multisegment ruptures and Vp/Vs variations during the 2020-2021 seismic crisis in western Corinth Gulf, Greece, Geophysical Journal International, 2022;, ggac081, https://doi.org/10.1093/gji/ggac081

Written in Matlab

Author: Maria Mesimeri