بررسی فعالیت نو زمین ساختی گستره سمنان با استفاده از شاخصهای ریخت زمین ساختی(فرازسنجی).

Abstract

Using morphotectonic indices are useful in high and remote mountaineous areas,where studying the activity of the faults (using traditional geological methods) is difficult and there isn't enough quaternery deposits in such regions for neotectonics studies.Hypsometry of drainage basins is one of the best methods for  evaluation of tectonics activity of regions.Nine drainage basins with different sizes and shapes were selected in Semnan region  in order to compare their activities on the basis of hypsometric parameters.In many cases, it's hard to recognize the effect of active tectonics from the effects due to the erusion,so the activity of an area may not be judged just  with a single morphotectonic indice and it requires other parameters to be in accordance with each other.For confirming  the Hypsometry parameter , the SL map of the area is prepaired and these two morphotectonics parameters are compared with seismic data.The SL indice is used just for confirming the hypsometry parameter ,and its sensitivity to the lithology is not of concern.The results show that tectonic activity is scattered in this part of Alborz range,and no unique pattern may be defined for it.It's clear that the basins in mountainous are show more activity than those which are in mountain front .In some areas the activity may be related to the junction between major faults with different strikes.