Investigation on effect of Tabriz North fault on the quantity and quality of groundwater resources in the vicinity of Tabriz East

Abstract

The North Tabriz Fault (NTF) is the most prominent tectonic structure in the Northwest of Iran. As results of this study, this fault has a major impact on hydrogeological conditions of the local aquifer. Plio-Quaternary volcanic ash and tuff layers constitute the only unconfined aquifer of this area which is directly lie on Miocene red marl as aquifer bed rock. Northern part aquifer bed rock placed in the higher level than the southern part. This could be the reason for the existence of the reverse dip-slip movement of fault in this area, which, in effect, the northern part (hanging wall) over trust on the southern part (footwall). Aquifer bed rock level sharp differences at a relatively low distances (less than 200 m), can be a sign of near-vertical slope for fault in this area. An obvious groundwater level differences which reaches to more than 8 meters along with the apparent differences between groundwater qualities across the fault at a low distance (about 200 meters) show a barrier behavior of fault against across fault flows. Total depth of southern part wells is four times of northern parts. Total annual discharge of southern part wells is about eight times of northern parts. Total hardness and ions concentrations of groundwater samples shows that most of northern part samples are not suitable for drinking purposes, but the southern part samples are suitable. Also, all of the northern part samples have the negative Langelier index (corrosive). All of the southern part samples have the positive (very close to zero) Langelier index and suitable for industrial usages. Therefore, most of industries in this area are located in the southern part of the fault.