abdolmajid asadi

Knowledge of the location of the blind fault and revealing fault length in urban areas are so critical. Moreover, recognizing and direct study of faults' location calls for selecting a proper approach to study the faults due to areas being covered with thick quaternary sediments and lack of faults outcrop in many areas. In doing so, one of the commonest methods is using geophysical methods. The study explored the blind faults of Banesh Plain in Fars, Iran using geoelectrical sampling with a Schlumberger array and integrating it with field sampling and direct observations. Accordingly, 30 soundings and 10 profiles were developed in this regard, and sections and pseudo-sections were analyzed. The results showed the existence of two fault zones along the northeast-southwest and northwest-southeast, and it seems that the conduction of groundwater in the mentioned area is under the influence of these two main zones.

The Sefid-Zakhur anticline is located in an area of Fars province where the gas potential on the Dehram horizon is high. The restored sections have been studied in three western, eastern and central parts of this anticline, deformation in this area is caused by a combination of compressive and shear deformation and tilting of layers in the end sections in the non-deformation stage, it indicates the existence of shear plates (separation horizons) between the stratigraphic units. Based on the order of formation of faults on sections, it can be concluded that first progressive thrusts and then as the deformation progresses, back thrusts are formed. The deformation in this region is related to the beginning of the Zagros deformation in Miocene time and is not older than that. According to the growth strata observed in the carbonate member of Gachsaran Formation in Sefid-Zakhur anticline, compression and folding in this area occurred during the Early Miocene. The southwestern part began to form earlier and formed as detachment fold with box geometry above the lower detachment horizon. In the higher deformations, the deformation occurs to the northeast, and the anticline forms detachment fold with a chevron geometry. The geometry of fold in the eastern part is a box fold. The degree of deformation in the eastern part is less than the central and west parts. Generally, Sefid-Zakhor field and its surrounding fields are formed based on the action and reaction of the compressive force of the region and the separation horizon.

One of the suitable & affordable methods for detecting karstic zones is geoelectric method. Geoelectric is one of the geophysical field operations, which is designed based on the transmission of electrical current into the ground, creating a potential difference between two points and calculating specific resistance of the ground in different depths. In this method, exploratory studies are carried out based on the standards for the resistance of different soil and rocks, as well as the electrical resistance values of materials such as water, metals, cavities, etc. In this research, in order to identify the karstic zones containing water in the Roniz plain in the west of Estahban, 97 electrical sounding were utilized using Schlumberger array and a maximum flow transmitter length of 300 m. After processing the data, Geological sections were prepared and analyzed. Finally, determined the hydraulic gradient of aquifer from west to east, based on specifying the saturated karsted zone in A2 sounding with a thickness of 140 meters at a depth of 260 meters has an electrical resistance of 100 to 150 ohms and at the place of D2 sounding at a depth of 150 meters with an electrical resistance of less than 100 ohms has 80 M thickness. That means, although the only seasonal river in this plain is near the D2 sounding, and therefore the rate of surface water in this area is at its highest, the maximum thickness of the subsurface aquifer is in the eastern part.

The axis of Mollasadra dam of x=604171 and y=3390531 at 39 zone is located near Sedeh village in Tange Boragh basin 125 km far from northwest of Shiraz.
Three morphometric indices, namely the VF, Mountain Front Sinuosity and hypsometric integration Index have been measured in different parts of the catchment area in order to reveal the tectonic activities. Analysis of the obtained data shows an increase of tectonics around the dam. The Mountain Front Sinuosity increases from 1.1 to 3.1.
Results show the studied area is active in the view of tectonic activity and it is located at group 2 in active tectonic classify.