On the time-scale of thermal cycles associated with open-vent degassing

摘要: Thermal imagery obtained with portable infrared cameras is widely used to track and measure volcanic phenomena. In the case of explosive eruptions, both air ground-based thermal monitoring have enabled collection data streams from relatively safe distances. Analysis these characterisation different regimes, parameterisation eruptive plumes, assessment on dynamics occurring in shallow system. Here we explore suitability imagers for investigating short time scale behaviour three basaltic volcanoes. We present high-time resolution image data-sets recorded at Etna, Stromboli Kīlauea volcano. At observations, all exhibited pulsed degassing. Signal processing mean apparent temperature time-series highlights four broad classes cyclic changes volcanoes based characteristic time-scales revealed periodograms: (1) <15 s, (2) ~20-50 (3) ~1-10 min, (4) 12–90 min. Based previous studies integrating results qualitative visible observations and, Kīlauea, also SO2 column amounts plume, hypothesise that cycles relate mainly bursting overpressured gas bubbles magma surface, while long might be associated mechanisms slug formation ascent, emplacement drainage a lava lake. slow fluctuations may reflect periodic variations lake surface level. The reveal superimposition degassing frequencies, suggesting link through common magmatic processes physical properties.