Variation of Moho Depth in the Central Alborz

Using teleseismic body waves, this paper presents the crustal and lithospheric structure in the central part of the Alborz Mountains for the first time. The region has been known as a very active and seismogenic locations in the past, characterized by strong earthquakes and complex structures. Tehran, the capital of Iran, is located on the southern part of the region. The aim of this study is to determine Moho depth and its variation beneath the Central Alborz with high resolution and accuracy. The crustal structure of the Central Alborz beneath 26 broadband stations from a temporary dense seismological network was determined by using recorded data deployed for a period of 4-6 months. We first summarize an analysis of the teleseismic P-wave receiver function beneath each station. Next, we use joint inversion of receiver functions with surface wave dispersion data calculated for the center of network. Results of this research are shown as cross-sections through N-S azimuth of the profiles which passes across the Alborz Mountains. Our study shows a thickening in the central part of the Alborz Mountains crust down to 55 km relative to 48-50 km crustal thickness beneath northern part of the Central Iran. The crustal thickness is close to 44 km beneath the southern coast of the South Caspian Sea Block. These results are completely unlike with most of the other previous suggested crustal thickness. Based on our results, the Alborz Mountains with a high average elevation can be considered with a crustal root.