Investigation of the Geothermally Contaminated Area after the Blowouts in Alasehir Using Magnetic and EM Methods

Geothermal activity around city of Manisa in Gediz Graben has been investigated by many researchers and many drillings has been opened in order to produce electricity and heating purposes. In the middle of May, 2012, a geothermal blowout occurred 150 m away from the deep drilling, during 1100 m, in Alkan village of Alaşehir resort in city of Manisa. After that, 4 big blowouts happened at the same area and hot water had been diverted to Alkan stream for almost 4 months. In this study, it was intended to determine contaminated area by using magnetic susceptibility measurements for the surface and VLF-R method for underground layers. All of the susceptibility values were mapped and contaminated areas was clearly defined on the surface using 346 data points. Besides, VLF-R studies were carried out along 18 profiles each of a length of 170 m at three different frequencies with a station spacing of 5 m. Laterally constrained two layer inversion was applied to each station and in addition to the inversion of all profiles for each frequency, all lines were stacked and 2-D views of the possibly contaminated (low resistive) zones which are covering approximately 35000 m2 were obtained.