Investigating plume dynamics using ground-based thermal infrared imagery at Sabancaya Volcano, Peru
Abstract
During May 21-26, 2018, we collected time series of high-resolution, ground-based thermal infrared and video imagery of varied eruptive activity at Sabancaya Volcano, Peru. We observed a wide spectrum of behavior, from emergent to impulsive, time-varying to continuous, involving emissions variously composed of ash and steam or gas. Plumes were observed in many cases to transition continuously between these regimes, reflecting fluctuation of source conditions. In fact, emissions were observed from multiple source regions within the crater, with distinct ash and gas plumes sometimes occurring simultaneously from different sources. Despite these fluctuations, of particular and striking note was the regular recurrence interval of approximately 4.5 hours for the largest explosive events. These events were impulsive, very hot, and ash-rich, reaching plume heights of 2-5 km above the vent. They were often preceded by an obvious decay in emissions on a timescale of minutes to tens of minutes, and followed by sustained emission for periods of minutes to hours. Data were recorded using a VarioCam HD thermal camera, in most cases with simultaneous and co-located imaging by DSLR cameras. The VarioCam instrument is broadband in the range of 7.5-14 mm, has a resolution of 1024x768 pixels, and recording distances were between 4.5 to 5.5 km from the vent, giving a pixel resolution of approximately 3 m. Image processing techniques applied to these data are being used to analyze plume properties and dynamics, with particular emphasis on comparing behaviour between events with widely varying ash and gas contents. Here we present preliminary results of the data analysis, in regards to these key research questions: 1) To what degree can ash/steam content be estimated from the thermal and visual data? 2) Do thermal properties and ascent dynamics vary as a function of relative ash/steam content? 2) Can water condensation during plume ascent be observed through changes in thermal properties and ascent dynamics? Insight gained from these data will be used to facilitate future modelling efforts that explore the influence of plume water content on transport and delivery of ash and gas emissions to the atmosphere.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.V51E0147R
- Keywords:
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- 3304 Atmospheric electricity;
- ATMOSPHERIC PROCESSESDE: 8419 Volcano monitoring;
- VOLCANOLOGYDE: 8428 Explosive volcanism;
- VOLCANOLOGYDE: 8488 Volcanic hazards and risks;
- VOLCANOLOGY