Source Parameters of the March 31st, 2006, Dorud Earthquake in Iran

The occurrence of the western iran earthquake of 31 march 2006 provided an importantopportunity to study the source properties of earthquakes in this region. although moderatein size (m l = 6.1, iiees), this earthquake was the largest to have occurred in the region sincethe deployment of the global digital seismograph network. the far-field data determination ofbody wave (p) spectra, interpreted in terms of the circular seismic source model, are used toestimate the parameters seismic moment (mo), corner frequency (fa) , source radius (r) andstress drop ((delta)(sigma)). p waves recorded at teleseismic distances can be obtained from stations ofthis network that are flat to displacement, in a frequency range of 0.19 to 0.32 hz. the averageseismic moment (mo = 14.92 x 10^19 n-m) and source radius (r = 9281 m) were calculatedfrom the long period spectral levels, which were corrected for the radiation pattern of a doublecouple point source. in addition, the stress drops ((delta)(sigma) = 87 x 10^6 n/m^2 ) ofthis event have beencalculated by using an average seismic moment and source radius. additional errors in the stressdrop determination are produced by uncertainty in the seismic moment. scatter in the seismicmoment values is caused by such factors as site condition and errors in the radiation pattern.