Determining lateral offsets of rocks along the eastern part of the North Anatolian Fault Zone (Turkey) using spectral classification of satellite images and field measurements

Abstract

Fault displacements are being measured by geological observations using the method of detecting and evaluating marker rocks. Thus, the length of total displacement in a fault zone relates to position detection of marker rocks. Due to limits of human eye, we used remote sensing data and terrestrial spectral measurements at 229 locations for measuring the total offset along the Kelkit Valley segment of the North Anatolian Fault Zone (NAFZ). We examined the lithology, especially ophiolites that are older than the fault zone and can be a good marker for detecting the total offset in the region. The Advanced Spaceborne Thermal Emission and Reflection Radiometer images are subjected to Spectral Angle Mapper (SAM) method. Principal component analysis, decorrelation stretching and geological map were used to compare the SAM results. Ophiolites on either side of the fault zone were clearly classified and identified with the SAM analysis. As a result of comparison of SAM with image enhancement methods and the geological map, we measured the total fault displacement on the NAFZ in the part of the Kelkit Valley. Along the fault zone to the north and south of the ophiolites providing a right lateral offset was measured as 90 +/- 5 km.