High-Resolution Regional Phase Attenuation Models of the Iranian Plateau and Surrounding Regions

Abstract : The objective of this project is to construct regional wave (Pg, Sn, and Lg) attenuation models for the crust and upper mantle throughout the Iranian plateau and surrounding regions. This research should increase ray path coverage of critical areas and help to create robust regional phase amplitude and attenuation models. We have combined our Iranian data set with our existing Middle Eastern Lg waveform database. These two data sets, combined, give us reasonably good coverage of the northern Middle East. We have created a catalog of seismic events in and around Iran with reliable source spectra as well as tested regional phase attenuation maps for the Zagros and Iranian plateau. We have developed an Sn attenuation model using two station measurements of Q for regional phase Sn (0.1 to 0.5 Hz) and for high frequency Sn (0.5 to 2 Hz). We have also processed Pg waveforms in order to obtain robust estimates of Qp in the crust within the Iranian plateau. For most of the phases we see moderately high attenuation within the plateau and less attenuation along the Zagros mountains. This project is the first to use two station and reverse two station methods to measure attenuation of phases such as Pg and Sn.