Monitoring surface deformations of active volcanoes in Turkey with geodetic techniques

Ranking 14th among 95 countries in terms of volcanic threat, Turkey has 7 volcanic systems (Mount Hasan, Tendürek Volcano, Mount Ağrı, Nemrut Volcano, Kula Volcanic Complex, Karacadağ, Mount Erciyes) that have been active in the last 10.000 years. According to the Global Volcanism Program, these volcanic systems in Turkey have caused 38 volcanic eruptions in the last 10,000 years and at least one volcanic eruption occurred every century between 1100 and 1900 AD. Although the last recorded volcanic activity was the gas and ash eruption from Tendürek Volcano in 1855, volcanoes that have been in a dormant state for a long time can continue their activities even after hundreds of years and pose a serious threat to the communities living in their surroundings. Therefore, detecting surface deformations, which are one of the earliest and most important indicators of volcanic activity, is a very important issue. This study aims to determine the surface deformations occurring in 7 active volcanic systems in Turkey according to the Global Volcanism Program. In this context, surface deformations between 2019 and 2023 were determined using the PSInSAR technique using GACOS delay products and Sentinel-1 SAR images obtained from descending and ascending orbits for the study areas. In addition, a geodetic network was established for the first time in Turkey for the purpose of monitoring volcanic areas in Mount Hasan, which was selected as a pilot area, within the scope of the TÜBİTAK 121Y401 project, and the findings obtained from GNSS and PSInSAR techniques were compared. As a result of the study, a deformation of approximately -1.5 cm/year was detected in Tendürek volcano and a general deformation of -2 to 5 mm/year was detected in the other 6 volcanic systems in Turkey.