Geochemical Monitoring Along the Türkoǧlu (Kahramanmaraş)-Gölbaşı (Adıyaman) Segments of the East Anatolian Fault System

We revisited the historical and instrumental period records and recognized that due to Gölbaşi{dotless}-Türkoǧlu and Türkoǧlu-Antakya segments of the East Anatolian Fault System (EAFS), densely populated Kahramanmaraş district is at great seismic risk. Therefore, in this study, Gölbaşi{dotless}-Türkoǧlu segment of East Anatolian Fault was continuously monitored by collecting data of different geochemical parameters of spring waters emanating from major fault segments (pH, temperature, conductivity, anion and cation concentrations) and correlating with seismicity. For this purpose, three online spring water observation stations located on the Gölbaşi{dotless}-Türkoǧlu segment of EAFS which is the most important source of earthquakes for Kahramanmaraş and its surroundings were established. Physical and chemical changes of the spring waters which are thought to be directly related to the fault were monitored. Spring water temperature and electrical conductivity and pH were measured on an hourly basis, whereas anion-cation concentrations were determined daily from bottled spring water samples. Dense seismology network run under the TURDEP Project (EOS Transactions, 88, 333-334, 2007) in the area provided means for monitoring earthquakes down to magnitude 1. We show that a magnitude 4.2 event (20 August 2008) caused significant changes in the geochemical parameters of a nearby spring. From the geochemical transients determined we conclude that there is a close relation between earthquakes and geochemical parameters of spring waters in the region. In order to see this correlation better, measurements of geochemical parameters should continue in the future.