Deformation of Eastern Turkey from seismic and geodetic strain rates

Abstract

Crustal deformation is the study of active geophysical processes that occur within the earth’s lithosphere. Geodesy provides facilities to investigate the earth’s crust movements and shares these data with the other disciplines. The various sources of geodetic data can be used to observe crustal deformation. Especially, GPS has gained wider acceptance worldwide for monitoring crustal dynamics for earthquake studies. GPS velocities help to improve the estimation of long-term strain rate tensor field. Seismic strain rates are also essential for determining seismic hazard of a region. Current studies show agreement between seismic strain rates inferred from earthquakes and regional tectonic strain patterns. In this study, a strain rate model was presented for the Eastern Turkey based on GPS velocities and earthquake focal mechanisms. The dense data coverage in this region allows a comparison of the seismic strain rate field with tectonic strain rate field observed geodetically. The principal strain rates were derived from the 16 GPS velocities (2003 - 2006) relative to Eurasia, which are in the range of 16 - 24 mm/year, and moment tensors of moderate-sized earthquakes with 30 years time span. The results are consistent with the current studies and strain rates confirm the active state of the secondary faults in the region. Key words: Crustal deformation, GPS, seismicity, NAFZ, EAFZ, focal mechanisms.