Crustal structure of Northwest Zagros (Kermanshah) and Central Iran (Yazd and Isfahan) using teleseismic Ps converted phases |
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| Authors: | Narges Afsari Forogh Sodoudi Fataneh Taghizadeh Farahmand Mohammad Reza Ghassemi |
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| Institution: | (1) Department of Physics, Qom Branch, Islamic Azad University, Qom, Iran;(2) Helmholtz Center Potsdam, GFZ Research Center for Geosciences, Telegrafenberg 14473, Potsdam, Germany;(3) Department of Physics, Islamshahr Branch, Islamic Azad University, Tehran, Iran;(4) Research Institute for Earth Sciences, Geological Survey of Iran, Azadi Sq., Meraj Ave., P.O.Box: 13185-1494, Tehran, Iran |
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| Abstract: | Receiver functions are widely employed to detect P-to-S converted waves and are especially useful to image seismic discontinuities
in the crust. In this study we used the P receiver function technique to investigate the velocity structure of the crust beneath
the Northwest Zagros and Central Iran and map out the lateral variation of the Moho boundary within this area. Our dataset
includes teleseismic data (M
b ≥ 5.5, epicentral distance from 30° to 95°) recorded at 12 three-component short-period stations of Kermanshah, Isfahan and
Yazd telemetry seismic networks. Our results obtained from P receiver functions indicate clear Ps conversions at the Moho
boundary. The Moho depths were firstly estimated from the delay time of the Moho converted phase relative to the direct P
wave beneath each network. Then, we used the P receiver function inversion to find the properties of the Moho discontinuity
such as depth and velocity contrast. Our results obtained from PRF are in good agreement with those obtained from the P receiver
function modeling. We found an average Moho depth of about 42 km beneath the Northwest Zagros increasing toward the Sanandaj-Sirjan
Metamorphic Zone and reaches 51 km, where two crusts (Zagros and Central Iran) are assumed to be superposed. The Moho depth
decreases toward the Urmieh-Dokhtar Cenozoic volcanic belt and reaches 43 km beneath this area. We found a relatively flat
Moho beneath the Central Iran where, the average crustal thickness is about 42 km. Our P receiver function modeling revealed
a shear wave velocity of 3.6 km/s in the crust of Northwest Zagros and Central Iran increasing to 4.5 km/s beneath the Moho
boundary. The average shear wave velocity in the crust of UDMA as SSZ is 3.6 km/s, which reaches to 4.0 km/s while in SSZ
increases to 4.3 km/s beneath the Moho. |
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