A study on the active crustal deformation of the north and east anatolian fault zones

Abstract

Active crustal deformation in the North Anatolian Fault Zone (NAFZ) and the East Anatolian Fault Zone (EAFZ), based on seismicity data, is examined. The results show that the deformation in the NAFZ is taken up by extension on an azimuth of 59° at a rate of 27 mm/yr and as compression on an azimuth of 149° and a rate of 20 mm/yr. The average dextral lateral motion on the NAF is about 23 mm/yr. This motion in the western part of the NAF is 16 mm/yr; while it increases in the eastern part of the fault to 27 mm/yr. In the EAFZ the deformation is taken up as nearly N-S compression (N7°E) at a rate of 5 mm/yr and as nearly E-W extension (N97°) at a rate of about 9 mm/yr. The average sinistral-lateral motion has a rate of about 6 mm/yr. The expected slip rates, from plate motions, along the North Anatolian Fault are of the order of 38 mm/yr. The predicted slip rates for East Anatolian Fault are 19 mm/yr or 29 mm/yr. The seismicity of the last 140 years can account for the expected deformation along the NAFZ: for the EAFZ, however, it is possible that part of the total deformation has been expressed aseismically.