Aeolian Remobilisation of Volcanic Ash: Outcomes of a Workshop in the Argentinian Patagonia

Abstract

During explosive volcanic eruptions, large quantities of tephra can be dispersed and deposited over wide areas. Following deposition, subsequent aeolian remobilisation of ash can potentially exacerbate primary impacts on timescales of months to millennia. Recent ash remobilisation events (e.g., following eruptions of Cordón Caulle 2011; Chile, and Eyjafjallajökull 2010, Iceland) have highlighted this to be a recurring phenomenon with consequences for human health, economic sectors, and critical infrastructure. Consequently, scientists from observatories and Volcanic Ash Advisory Centers (VAACs), as well as researchers from fields including volcanology, aeolian processes and soil sciences, convened at the San Carlos de Bariloche headquarters of the Argentinian National Institute of Agricultural Technology to discuss the “state of the art” for field studies of remobilised deposits as well as monitoring, modeling and understanding ash remobilisation. In this article, we identify practices for field characterisation of deposits and active processes, including mapping, particle characterisation and sediment traps. Furthermore, since forecast models currently rely on poorly-constrained dust emission schemes, we call for laboratory and field measurements to better parameterise the flux of volcanic ash as a function of friction velocity. While source area location and extent are currently the primary inputs for dispersion models, once emission schemes become more sophisticated and better constrained, other parameters will also become important (e.g., source material volume and properties, effective precipitation, type and distribution of vegetation cover, friction velocity). Thus, aeolian ash remobilisation hazard and associated impact assessment require systematic monitoring, including the development of a regularly-updated spatial database of resuspension source areas.

Ash emission from a long-lived eruption at Popocatépetl volcano and mapped respiratory effects

“…Eolian remobilization of volcanic ash could be a factor exacerbating spatial and temporal the NIRD rates. However, studies on volcanic ash remobilization are still in their infancy (Jarvis et al 2020), and specific data to allow us to separate out these effects are not yet available for the Popocatepetl area. However, as a result of our findings here, the variables associated with volcanic activity (ash thickness, grain size, componentry, and chemical composition) and variations in NIRD rates remain under continuous study as part of the ongoing research of the working group.…”

Impact of climate change on volcanic processes: current understanding and future challenges

“…Lahars and airborne remobilisation of volcanic deposits are also dependent on extreme and seasonal rainfall (e.g. Kataoka et al, 2018;Paguican et al, 2009;Jarvis et al, 2020) and could be affected by climate change.…”

Communication when it is needed most—the past, present and future of volcano geoheritage

“…There is commonly synergy between two or more commissions with overlapping interests. Examples of best practices include volcano observatory consortia for eruption forecasting, hazard communication and long-term hazard assessment (Pallister et al 2019), risk assessment in volcanology including hazard, exposure and vulnerability (Bonadonna et al 2018), numerical model comparison of volcanic eruptive columns (Costa et al 2016) and aeolian remobilization of volcanic ash (Jarvis et al 2020), among others. Collaborative resources are numerous today.…”