Coda Wave Spatial Variation in Eastern Anatolia, Turkey

Abstract

Eastern Anatolia is a tectonically active area, where continent-to-continent collision and accretion processes are shaping the crust and leading to high seismic characteristics. The main motivation of this research is to calculate the Coda Wave Spatial Variation in the depth and horizontal plane using 3438 events recorded by 26 seismic stations. The Coda Q features from 1 to 16 Hz are computed for various lapse times, which determine the coda waves depth distribution. The contours of Q-variation in the regional crust at different depths are obtained. The Coda-Q values range from ~180±120 at 1 Hz to ~800±500 at 16 Hz in the study area. The Q characteristics are interpreted concerning tectonics, crustal anomalies, and possible geothermal regime variations. Low Q values are observed in and around major fault-lines, zones of high tectonic activity, and geothermal spots. The results suggest that 8 Hz coda-Q distribution may be associated with the Curie point depth distribution. Low Coda-Q values specifies high attenuation features, while low-frequency exponent can define clear principal attenuation according to molten lower crust along Arabian-Anatolian plate collision zone and presence old volcanic units, such as Tendürek, Agri, Süphan, and Nemrut Mountains scattered all around the study area, as well as geothermal reservoirs.