Determination of the Preliminary Velocity Model Using Receiver Function Analysis Method with DEUNET Seismological Observation Network Data

Abstract

The Western Anatolia and Aegean Region, renowned for its history of potent earthquakes, necessitates a specialized seismic velocity model for precise hazard assessments. This research leverages DEUNET Seismological Observation Network data to establish a region-specific velocity model. Fifteen teleseismic earthquakes (2019 to January 2023) were carefully selected, ranging from magnitudes 7.5–8.2, based on signal-to-noise ratios exceeding three. Epicentral distances spanned 30° to 90°. Station noise analysis involved choosing suitable earthquakes for spectral assessment. Steps included instrument response-based restitution and horizontal-to-radial/tangential component transformation (SAC software). Z components largely reflected direct P phases, while R components dominated Ps phases. ZRT to LQT rotation enabled Ps and P wave separation. The focus lay on P-SV-SH wave phases. L components conveyed strong P wave signals, while Q and T components featured converted S wave energy. Deconvolution effectively removed source and ray path contributions from L component P wave signals. The inversion performed subsequently determined the subsurface S-wave velocity structure based on depth. The station with the lowest signal-to-noise ratio, Çeşme, emerged from noise analysis. Receiver function analysis determined crust-mantle boundaries for DEUNET stations, indicating depths between 13 and 39 km.