Globally, about 250 Holocene volcanoes are either glacier-clad or have glaciers in close proximity. Interactions between volcanoes and glaciers are therefore common, and some of the most deadly (e.g., Nevado del Ruiz, 1985) and most costly (e.g., Eyjafjallajökull, 2010) eruptions of recent years were associated with glaciovolcanism. An improved understanding of volcano-glacier interactions is therefore of both global scientific and societal importance. This study investigates the potential of using optical satellite images to detect volcanic impacts on glaciers, with a view to utilise detected changes in glacier surface morphology to improve glacier-clad volcano monitoring and eruption forecasting. Roughly 1400 optical satellite images are investigated from key, well-documented eruptions around the globe during the satellite remote sensing era (i.e., 1972 to present). The most common observable volcanic impact on glacier morphology (for both thick and thin ice-masses) is the formation of ice cauldrons and openings, often associated with concentric crevassing. Other observable volcanic impacts include ice bulging and fracturing due to subglacial dome growth; localized crevassing adjacent to supraglacial lava flows; widespread glacier crevassing, presumably, due to meltwater-triggered glacier acceleration and advance. The main limitation of using optical satellite images to investigate changes in glacier morphology is the availability of cloud- and eruption-plume-free scenes of sufficient spatial- and temporal resolution. Therefore, for optimal monitoring and eruption prediction at glacier-clad volcanoes, optical satellite images are best used in combination with other sources, including SAR satellite data, aerial images, ground-based observations and satellite-derived products (e.g., DEMs).

Many (about 250) volcanoes worldwide are occupied by glaciers. Often glaciers are regarded as problematic for volcano monitoring, since glacier ice potentially masks evidence of volcanic activity. The most devastating volcanic eruptions of the last 100 years involved volcano-glacier interactions. The 1985 eruption of Nevado del Ruiz killed 23000 people, and the 2010 eruption of Eyjafjallajökull led to the closure of many European airports. Therefore, it is imperative to minimize these impacts on society by improving methods for monitoring of glacier-clad volcanoes. Amongst several methods, optical satellite remote sensing techniques are perhaps most auspicious, since they frequently have a relatively high temporal and spatial resolution, and are mostly freely available. They often clearly show the effects of volcanic activity on glaciers, including ice cauldron formation, ice fracturing and glacier terminus changes potentially due to subglacial melt or subglacial dome growth. This study has the objective to link pre-, syn- and post-eruption glacier behaviour to the type and timing of volcanic activity, and to develop a satellite based predictive tool for monitoring future eruptions. Despite several studies that link volcanic activity and changing glacier behaviour, the potential of using the latter to predict the former has yet to be systematically tested. Our approach is to observe how glaciers responded to past volcanic events using mostly, but not exclusively optical satellite imagery, and to build a database of examples for potential automated detection and forecasting on a global scale.

Many (about 250) volcanoes worldwide are occupied by glaciers. This can be problematic for volcano monitoring because glacier ice potentially masks evidence of volcanic activity. Both the deadliest and most costly volcanic eruptions of the last 100 years involved volcano-glacier interactions. The 1985 eruption of Nevado del Ruiz killed 23000 people, and the 2010 eruption of Eyjafjallajökull led to the closure of many European airports. Therefore, improving methods for monitoring glacier-clad volcanoes is of clear societal benefit. Amongst several methods, satellite based remote sensing techniques are perhaps most promising, since they frequently have a relatively high temporal and spatial resolution, and are mostly freely available. They can help to identify the effects of volcanic activity on glaciers, including ice fracturing, ice surface subsidence and glacier acceleration potentially due to subglacial melt or subglacial dome growth. This study aims to link pre-, syn- and post-eruption glacier behavior to the type and timing of volcanic activity, and to develop a satellite based predictive tool for monitoring future eruptions. Despite several studies that link volcanic activity and changing glacier behavior, the potential of using the latter to predict the former has yet to be systematically tested. Our approach is to use satellite imagery to observe how glaciers responded to past volcanic events, and to build a training database of examples for automated detection and forecasting.