Monitoring the Fault Zone of the Sefid Sang Earthquake (April ۵, ۲۰۱۷, Mw ۶.۱) via Ambient Seismic Noise Analysis Utilizing the Moving Window Cross-Spectral Technique

The Passive Image Interferometry (PII) approach, which incorporates a cross-correlation process to reconstruct the green function between two stations, is emerging as an effective tool for studying seismic velocity changes. These changes provide significant information about the earth's structural and mechanical properties between the stations. Despite its numerous benefits, monitoring fault zones with PII can be challenging due to various processes that can cause velocity changes in the crust. In this study, we investigated the usefulness of this method on the noise recorded in two seismic stations near the fault zone that caused the Sefid-Sang earthquake with a magnitude of Mw = ۶.۱. Our study covers a period of ۱۵ months, including ۱۲ months before and three months after the earthquake. We investigated velocity changes across different frequency ranges and examined the effect of stacking on the results. Our analysis revealed a ۰.۳% increase in seismic velocity two months before the earthquake.

کلیدواژه ها:

interferometry ، Passive image ، Cross-correlation ، Green function ، Iran