Attenuation and propagation characteristics of seismic waves in Iran

Seismic wave propagation of crustal phases for Iranian earthquakes is examined through different parts of Iran by studying records from the Iranian National Seismological Network (INSN), stations of Mashad University and Iranian Long Period Array (ILPA). The selected crustal phases for analysis were P (Pn or refracted P), Pg, Sn and Lg. Three component rotated seismograms were bandpass filtered (0.1 to 5 Hz) and the presence and amplitude of Sn and Lg were examined relative to the Pn and Pg phases. Also, the data of Iranian stations were used to determine coda Q over a small area (200 km by 200 km) for small earthquakes. According to this research, Q varies with frequency in different parts of Iran as follows:Western Iran: Q=105 f 1.02-North-Central Iran: Q=147 f 0.97-South-Central Iran: Q=138 f 1.06-North-Eastern Iran: Q=151 f 1.01- Eastern Iran: Q=169 f 0.86-South-Eastern Iran: Q=194 f 0.77-The results of previous works such as Rodgers et al. (1997) were used to complete the gaps of Iranian records in some parts of Iran.