Multisource and temporal thermal infrared remote sensing of Hasandag Stratovolcano (Central Anatolia, Turkey)

Abstract

Hasandag ˘ is a double-peaked long-dormant volcano, where associated volcanic risk is poorly known and needs to be assessed. Weak fumaroles and water vapor emissions have been observed at several vents, on the western flank of the Greater Hasandag ˘ summit, between 3000 and 3100 m (a.s.l.). The highest temperature and CO2 values measured in those vents were ~ 70 ◦C and > 100,000 ppm respectively. Multisource and wide-period thermal remote sensing analyses were performed to investigate the thermal state and to test the possibilities of remote thermal monitoring of the volcano. MODIS daily surface temperature data were analyzed for a period of 18 years. We used a statistical approach using the Seasonal Decomposition of Time-series procedure to decompose the temperature data into the trend, seasonal, and remainder components. The trend component was used to analyze temporal thermal anomalies in comparison to the decomposed meteorological temperature data. 56 nighttime ASTER TIR imagery acquired between 2001 and 2018 had been used to derive and analyze the Surface temperature, Surface temperature anomaly and Relative radiative heat flux. High-resolution ground-based and aerial thermal mosaic images were built to investigate the thermal radiation over the summit fumarole zone and its structural dependence. A baseline reference value for thermal monitoring of the fumarole zone was achieved using remotely sensed data and time-series decomposition of long-term TIR data. The resolution of the thermal imagery positively affects the mapping and monitoring capability. A permanent ground-based thermal observation station should be established for direct and remote thermal monitoring of the fumarole zone.