Geology of the Çaldıran Fault, Eastern Turkey: Age, slip rate and implications on the characteristic slip behaviour

Abstract

The Çaldıran Fault is a strike slip fault with a dextral slip in East Anatolia. The activity on this fault was marked by the November, 24 1976 earthquake (Mw: 7.1) which produced an ~50km long surface rupture and caused 3840 fatalities, which was close to half of the population living along the fault at that time. Together with the North Tabriz Fault in Iran, it is regarded as the southern boundary of the Caucasus Block. The fault has an average annual slip rate of 8.1 from 10.8mmyr−1, as derived from elastic block modelling. We present results from a detailed morphotectonic survey along the fault. The Çaldıran Fault is comprised of three segments, each of which is eparated by bend structures that bend towards the SW with a total change in strike of 20° from east to west. The offsets of lithological contact markers show that the long-term geological slip rate for the Çaldıran fault is approximately 3.27±0.17mmyr−1for a duration of approximately 290ka. The cumulative offset of the fault was determined from an analysis of a dome-shaped rhyolitic volcano which constrained the age of the fault to the Middle–Late Pleistocene. An analysis of small-scale morphological offset markers indicates a characteristic slip behaviour of the Çaldıran Fault for the last 3 events with an average offset of 2.6m.