Crustal Structure beneath SLY1 Station from Joint Inversion of Receiver Function and Surface Wave Dispersion Analyses, Sulaymaniyah Area, NE Iraq

Abstract

The crustal structure beneath the Sulaymaniyah area in northeast Iraq which is located in a seismically active zone, was investigated and the results were presented in this study. Teleseismic and regional earthquakes recorded by the Sulaymaniyah broadband seismic station (SLY1) were used to conduct the P-wave receiver functions and Rayleigh wave group velocities using Computer Programs in Seismology (CPS). Joint inversion of receiver functions and surface waves dispersion curves were used to infer the crustal structure below the station. The waveforms were analyzed for 72 earthquakes with epicentral distances ranging from 30º to 90º that occurred during the period from October 2015 to Oct. 2021 with magnitudes ≥ 7Mw. The generated crustal model shows that the sedimentary cover in the area is around 6km with a P-wave velocity of 5.4817km/sec and Moho discontinuity around 48km with a P-wave velocity of 8.0560km/sec. These outcomes indicate that the crystalline crustal thickness at Sulaymaniyah station is 42 km with a P-wave velocity ranging from 5.4817km/sec to 8.0560km/sec. There are two sharp discontinuities around 20km and 38km with P-wave velocities of 5.9182km/sec and 7.1485km/sec respectively. It is believed that these are the discontinuities between the upper, middle, and lower crust.