Usefulness of IR thermography surveys in the archeological site of Hierapolis in Phrygia (Turkey)

IR thermography is a fundamental remote sensing technique in many physics and engineering applications, as well as in the field of the Cultural Heritage for the conservation and maintenance of existing buildings or surfaces with artistic value. The literature reports many works showing the effective usage of IR thermography for various tasks such as the detection of structural anomalies in masonries and in buildings, or as diagnostic tool for predictive maintenance, allowing the identification of water infiltration, rising dampness, detachment, thermal bridges, and energy leaking from the building's envelope. The use of the IR thermography in the archeological site of Hierapolis in Phrygia has been devoted to the survey in two operative modalities: ?in close-range modality for the investigation of rising dampness, and detection/sizing of detachments and anomalies on wall paintings and on walls in the Insula 104 (S. Vettori, paper submitted), a residential area dated at proto-byzantine period; ?in long-range modality to investigate the warm air flow at the area of Ploutonion, the sanctuary of the Gods of Underworld, Hades and Kore, with the theater above a grotto (Theatron), discovered during the 2012 excavation campaign of the Italian Archaeological Mission (D'Andria, 2013); ?and, always in long-range modality for the scanning of terrain by aerial IR photography from a tethered balloon in order to mapping the increasing of soil temperature due to the proximity of fracture over the active fault, due to the fact that Hierapolis town is longitudinally cut by several parallel fractures of the Hierapolis fault zone (Altunel and Hancock, 1996; D'Andria and Silvestrelli, 2000; Scardozzi 2015). The perspective to employ the IR thermography for survey of problems and risks for the conservation of the ruins archaeological has been demonstrated in the site of Hierapolis in combination with several exhaustive diagnostics campaigns performed during archaeological missions in 2013, 2014 and 2015, made in order to characterize the mainly decay processes present on ruins of the site. The results of the aforementioned analyses and their correlation with the IR thermography results will be presented. This research activity has been co-founded by the Ministry of Education, Universities and Research in the framework of the FIRB project "Marmora Phrygiae".