Role of tectonics in the evolution of Taftan Volcano, SE Iran

Abstract

The study of factors that control volcanoes can help analysesize the risk of triggering an the next eruption. Taftan is a Quaternary volcano of southeast Iran, formed as the result of subduction of Oman oceanic lithosphere underneath the continental Iranian plate that emplaced onto compressional tectonic setting such as strongly folded and faulted Eocene flysch and Cretaceous ophiolites. This volcano has several centers that are directed along a northeast to southwest from old to new. In order to investigate the role of the tectonic regime to evolution of Taftan volcano, structural elements such as Dikes, Fractures, crater opening of Anjerk amphitheater, the direction of centers and direction of springs have been studied. The resulting data of these elements represent a northeast-southwest directed extensional stress in the Taftan body which has created an extension area in the northwest-southeast direction. But earthquakes and structural trends of pre volcanic rocks underlying Taftan show a maximum regional compressional northeast-southwest striking. Recent relevant data such as structural analysis, analog modeling, field data demonstrating that volcanism can occur in compressional tectonic settings associated with thrust faulting. In other words magma can transport beneath the volcano to the surface along the thrust faults. Based on these data we proposed a model that demonstrates the substrate thrust fault (as magma path) splits into two faults within the volcano: A shallow-dipping one, with reverse movement, propagates towards the volcano flank, and a steeper-dipping one, with normal movement, propagates upwards and causes northeast-southwest extensional area along the centers parallel to thrust fault of substrata. The suggested model in this study proposes a next eruption point in the southeast of the currently active point.

Keywords

• volcano
• compressional tectonics
• reverse faults
• dike
• hazard