Probable regional geothermal field reconnaissance in the Aegean region from modern multi-temporal night LST imagery

Abstract

The Hellenic Peninsula and the adjacent Aegean and Ionian seas are segmented into regions on the basis of Terra satellite-MODIS instrument derived land surface temperatures (LST) to test if they can be used in the field reconnaissance for potential geothermal targets, each region representing a different thermal signature. The method has been used successfully to identify hot spot and geothermal activity in the Afar Triangle and in the Red Sea. Night monthly average LST values per pixel, since 2001, are used in this work for geothermal field identification. Average LST seasonal variability is expressed by a common centroid curve of pixel cluster. Clusters were subsequently ranked in increasing LST according to their centroids. Cluster-2 represents by far the Aegean volcanic arc (AVA) which comprises the high enthalpy (320 and 350°C, respectively) geothermal fields of Milos and Nisyros. The interpretation of LST terrain segmentation into sub-clusters of Cluster-2 is consistent with thermal anomalies related to the volcano-islands of the AVA, the occurrence of thermal anomalies related to granodiorite plutons in the Cyclades and to the volcano-related anomalies of the Dodecanese Province. We conclude that the identification of such thermal anomalies obtained by a combination of remote sensing (LST), regional geology and field data (borehole, thermal spring and subsurface hydrothermal reservoir temperatures) can be a particularly useful exploration tool for localizing geothermal anomalies.