Crustal Velocity Structure in Iranian Kopeh-Dagh, from Analysis of P-Waveform Receiver Functions

Nowrouzi, Gholamreza; Priestley, Keith F.; Ghafory-Ashtiany, Mohsen; Javan Doloei, Gholam; Rham, Daniel J.

Crustal Velocity Structure in Iranian Kopeh-Dagh, from Analysis of P-Waveform Receiver Functions

Document Type : Seismology and Engineering Seismology

Authors

Gholamreza Nowrouzi ¹

Keith F. Priestley ²

Mohsen Ghafory-Ashtiany ¹

Gholam Javan Doloei ¹

Daniel J. Rham ²

¹ IIEES

² Department of Earth Sciences, University of Cambridge

Abstract

In this study, the crustal velocity structure and depth of Moho is determined under the eastern part of Iranian Kopeh Dagh, North-East Iran that is named Hezar-Masjed mountains. The teleseismic waveform receiver functions technique is used to determine crustal thicknesses in this study. 41 teleseismic earthquakes from three broadband seismometers installed in the Iranian Kopeh-Dagh, are used to calculate P-wave receiver functions. Receiver functions for each station are generated from events for a wide range of backazimuths. From analysis of receiver functions at KAR, ZOW and HAM stations, the crustal structure is suggested for the Hezar-Masjed area with a Moho depth of 44-50km. Results indicate three main layers; the upper crust has an S-wave velocity between 2.1-3.2km/s and a 10 to 12km thickness, a middle crust with S-wave velocity between 3.2-3.7km/s and a 22 to 25km thickness and the lower crust with S-wave velocity between 3.7-4.4km/s and a 12 to 15km thickness. An S wave velocity between 4.6-4.7km/s indicates the velocity of the Moho at 47km on average and varies from 44 to 50km. Deeper Moho is found under the southern station.

Keywords

Kopeh-Dagh

Hezar-Masjed Mountains

Crustal Structure

Moho Discontinuity

Teleseismic Receiver Functions