Investigation of the internal Structures and Determination of the Type of the Glacier using the Ground Penetrating Radar (GPR) Method: A Case Study - Alam Kuh Glacier, Mazandaran Province

The method of ground penetrating radar (GPR) has increasingly been used for investigation of surface and internal structures of glaciers within the last few decades. This geophysical method distinguishes different structures of glaciers considering the existence of electrical permittivity contrast between ice, air, sediment debris and water in the glaciers. In this research, the GPR acquired data using unshielded antenna with central frequency of 25 MHz along 3 lines in Alam kuh glacier, Kelardasht, Mazandaran, in June 2012, have been processed and interpreted. In order to remove the effect of low-frequency unwanted reflections overlain on high-frequency reflections from all GPR sections, we have used dewow filter. Moreover, we have used gain function for signal enhancement, especially in late times of the GPR data acquisition. Considering the coarse topography of the study area, we have also applied topography correction on the data, and then, the obtained results have been compared with the obtained results without topography correction to demonstrate the importance of topography correction on GPR data. Moraine materials, covered the surface of the area, are mainly fine-grained granite. The bed rock or basement in the area is also granite. The polarity representing ice-bed rock is clearly seen on the GPR profiles. Furthermore, the results of this research indicate that recognition of moderate and cold ice areas in the glacier, type of the glacier (Multi-thermal), holes and topography of the glacier basement has successfully been possible using only the GPR method. The electrical resistive nature of the glacier has caused large depth of penetration of GPR waves in this research work.