Feeling the heat: global detection of volcanic effects on glacier mass balance and dynamics

With the availability of open-access satellite imagery and derived products from open-source tools, global studies of glaciers have become increasingly manageable. Many studies have used these global datasets to delineate spatial and temporal variations in glacier mass balance and dynamics. This has highlighted the effects of seasonal fluctuations and climatic trends on glaciers and has aided the identification of glacier surges. Here we focus on the often-neglected effects volcanoes may have on glacier mass balance and dynamics. First, we analyse the elevation distribution of the world’s glaciers with respect to their proximity to volcanoes and find that there is measurable evidence of the negative mass-balance effect volcanoes have on nearby glaciers. Second, we use the ITS_LIVE glacier velocity dataset along with the new TICOI regularisation and signal decomposition to identify velocity anomalies on glaciers located around volcanoes. This allows us to discern both short-lived velocity anomalies as well as long-term trends and variations in seasonal patterns. We identify multiple velocity anomalies, many of which correlate with climatic trends or weather events, others with surges, but some stand out as volcanically induced. We demonstrate examples of what effect various volcanic processes such as geothermal activity, mass wasting events, unrest, and pre-eruptive activity can have on glacier velocity.