Abstract

Abstract In this study we determined the stress regime acting along the East Anatolian Fault Zone between Turkoglu (Kahramanmaras) and Celikhan (Adiyaman), from the Neocene to present-day, based on the inversion of striations measured on faults and on the focal mechanisms of earthquakes having magnitudes greater than 5.0. The inversions yield a strike-slip stress regime with a reverse component (i.e., transpression) operative in the Neocene to present with a consistent N-to NW-trending σ1 axis 156 ± 11° and an E- to NE-trending σ3 axis, 67 ± 9°σ3, producing left-lateral motion along the East Anatolian Fault Zone. The inversions of focal mechanisms yield a strike-slip stress deviator characterized by an approximately N-S (N89°W)-trending σ1 and an approximately E-W (N89°E)-trending σ3 axis. Both the kinematic analysis and structural observations indicate that the stress regime operating in the study area has had a transpressional character, giving rise to the Mio-Pliocene compressive structures (reverse faults, thrusts and folds) observed in the study area. Field observations allow estimation of a Pliocene age for the strike-slip East Anatolian Fault Zone.

Highlights

  • Africa-Eurasian convergence and the Arabia-Eurasia collision zones profoundly influence the eastern Mediterranean tectonic framework (Fig. 1)

  • The results of the inversion of all the fault-slip vector datasets belonging to the leftlateral deformation stage correspond to the σ1 and σ3 directions shown on the simplified tectonic map of the study area (Fig. 7)

  • The Neocene stress regime operating in the study area has a strike-slip character with a reverse component

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Summary

Introduction

Africa-Eurasian convergence and the Arabia-Eurasia collision zones profoundly influence the eastern Mediterranean tectonic framework (Fig. 1). The neotectonic regime of Turkey is mainly controlled by the continuing northward motions of the African and Arabian plates with respect to Eurasian plate, which began in the Middle-Late Miocene and resulted in the westward extrusion of the Anatolian block along the North and East Anatolian fault zones (McKenzie, 1972; Dewey and Sengor, 1979; Sengor and Yilmaz, 1981; Jackson and McKenzie, 1988). Upper Cretaceous ophiolitic rocks have been thrust onto an unconsolidated continental red conglomerate of probable Plio-Quaternary age at a site 10 km southeast of Golbasi (Fig. 2(a)). This south-vergent retrocharriage deformation type (or back-thrust faults) indicates a transpressive/compressive regime, with N-S shortening during PlioQuaternary time. The most destructive earthquake recorded since 1900 was on December 4, 1905 (M > 6.8) and caused a 38-km-long surface rupture in the northern end of the present study area

CELIKHAN ADIYAMAN
Pleistocene conglomerate
Lat N Long E
Discussion and Conclusions
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