Late Pleistocene-Holocene lake terraces, water level change, and active tectonics: Eastern coast of Lake Van, Eastern Anatolia, Turkey

摘要

Data obtained from mapping, topographic analysis and radiometric dating completed in the epicentral region of the 23 October 2011 Van earthquake reveals the role of tectonic processes on the terrace formation. An investigation of seven terraces between Bardakci and Yesilsu villages on the hanging wall of the Van Fault Zone indicates changes in the Holocene coastline of Lake Van and provides information regarding the relationships between the changes and tectonic uplift in the region. Taking note of the elevation of the terraces, seven terrace levels appeared within the last 30 ka. Three of them are interpreted as tectonic origin. According to the dates and heights of the tectonic terrace levels, the mean annual uplift rate is calculated to be = 2 mm/year on the hanging wall of the Van Fault Zone. Additionally, mapping occurred of folds with generally E-W direction, occasionally NE and NW orientation, developed within the Quaternary deposits. Assessment of the obtained data shows uplifting of the area, with the effect of reverse faults/thrusts and folds developed by the N-S compression during the Plio-Quaternary an important factor in terrace development in the region.