Late Cenozoic stress distribution along the Misis Range in the Anatolian, Arabian, and African plate intersection region, SE Turkey

Abstract

This study defines the Mio-Pliocene to present-day stress regime acting at the northeastern Mediterranean along the SE border of the Neogene Adana basin along the Misis Range. The inversion of earthquake focal mechanisms shows that the present-day state of stress is dominantly a transtension, combined the strike-slip and extension with a consistent ENE (N83°E) trending σHmin (σ3) axis. The inversion slip vectors measured on fault planes and chronologies between striations indicate a consistent strike-slip stress regime that varied from transpressional initially to transtensional during Pleistocene time, with the latter continuing into recent times as indicated by earthquake focal mechanism inversions. Both states have consistent NNW (N15°W) trending, compatible with NNW Arabian drift direction, and ENE (N75°E) trending σHmax (σ 1) and σHmin (σ3) axes, respectively, but have significantly different mean arithmetic stress ratio (Rm) values: Rm = 0.75 indicating transpression for the old regional stress regime and Rm of 0.20 denoting transtensional for the younger regional stress regime. The crosscutting of striations confirms also the change within the strike-slip stress regime. Both stress regimes induce sinistral displacement along the major strike-slip fault systems, i.e., East Anatolian Fault, Karatas-Osmaniye Fault. The temporal stress regime change probably occurred during Quaternary time and resulted from coeval influence of the superimposed forces owing to subduction processes in the southwest along the Cyprus arc, continental collision in the east, and westward escape of the Anatolian Block in the north and west. Copyright 2004 by the American Geophysical Union.