MONITORING OF VELOCITY CHANGES NOVEMBER 12th, 2017 EARTHQUAKE, SARPOL-E ZAHAB WITH MOVING WINDOW CROSS SPECTRAL TECHNIQUE

Ambient noise is instrumental in the consistent investigation of seismic characteristics of the earth. One of these seismic characteristics is seismic velocity, which can be monitored consistently by ambient noise. In this paper, we took the advantage of Moving Window Cross Spectral (MWCS) method and MSNoise Python package (Lecocq, Caudron, & Brenguier, 2014) for studying of velocity variation of M-w 7.3 12 November 2017 Sarepol-e Zahab earthquake. At the first step, one-year continuous recordings of two Iranian seismological center (IRSC) (Dehrash (DHR) and Layen (LIN)), which are the nearest stations to the earthquake epicenter, were processed to compute daily cross- correlation function (CCF) in different filter ranges. According to MWCS method, daily CCF were stacked linearly for the whole period of this study called reference CCF, and in this case study, we compared linear stack of daily CCF for every 5 days, 10 days, 30 days, which is called current CCF. Finally, for the frequency range of 0.1-0.5 Hz, and with considering that the coda part of CCF is in the time lags between 15 to 50 second on both sides, the coseismic velocity decreased by 0.1% in the 30- day current stack.

کلیدواژه ها:

Velocity changes Monitoring ، Moving Windows Cross Spectral method ، MSNoise Python package ، Sarpol-e Zahab ، Earthquake