Estimates of plume height from infrasound for regional volcano monitoring

Present efforts in volcano monitoring, particularly in Southeast Asia, rely on the combination of local data (generally gathered at less than 100 km from the volcano), and satellite remote sensing. While this combination has its strengths, there are still weaknesses that the use of ground-based remote sensing data - such as distant infrasound measurements - could help alleviate. Infrasound offers tools for detecting and characterizing volcanic plumes independent of cloud cover and time of day. Larger volcanic eruptions generate infrasound that is related to the plume and offers a unique view into eruption dynamics within the context of monitoring. Past research has demonstrated that infrasound can be used to estimate source parameters, such as the rate at which material is ejected from volcanic vents during eruptions; these are key input parameters into empirical and numerical models to estimate the height of volcanic plumes, atmospheric ash transport and dispersion. Here, we demonstrate the use of remote infrasound in estimating the height of volcanic plumes, including a case study on the May 30, 2014 plume from the volcano Sangeang Api in Indonesia. We were able to determine the plume height using infrasound gathered from 2000 to over 5000 km distance from the volcano. During the January 2020 eruption of Taal volcano in the Philippines, this method was applied to remote infrasound recorded 1650 km to the east. We show that our workflow can be implemented in near real-time, offering an effective tool for rapid plume height measurement, including associated uncertainties, when volcanic clouds are not visible from the ground or space.