سید رضا منصوری

Abstract Rotational seismology is an emerging field for studying all aspects of rotational ground motions induced by earthquakes, explosions, and ambient vibrations. It is of interest to a wide range of geophysical disciplines, including strong-motion seismology, broadband seismology, earthquake engineering, earthquake physics, seismic instrumentation, seismic hazards, seismotectonics, and geodesy[lee et al]. The seismic waves that spread out from the earthquake source to the entire Earth are usually measured at the ground surface by a seismometer which consists of three orthogonal components (Z (vertical), N (north-south), and E (eastwest) or R (radial), T (transversal), and Z (vertical)). However, a complete representation of the ground motion induced by earthquakes consists not only of those three components of translational motion, but also three components of rotational motion plus six components of strain[Wiwit suryanto]. The main objective of the paper, is investigation the rotational components of deformation using seismic data in Sought Khorasan Zone. Historical evidence shows that major part of deformation (50-100 percent) is caused by seismic events which occurred in this zone. Therefore, to calculate seismic displacement tensor and tensor rotational strain, seismic data were used. The rotational strain tensor calculation provides contribution of the rotation effect around the vertical, North-South and East-West. The results of this study can be used to complete those with other methods to improve information of the deformation in this zone.