Volcanic ash impacts on water transport networks after three widespread tephrafalls in Patagonian lakes, Argentina

SALGADO, PABLO A.; VILLAROSA, GUSTAVO; BEIGT, DÉBORA; OUTES, VALERIA; WILSON, THOMAS M.; STEWART, CAROL

Heraclio

Conferencia; Cities on Volcanoes 11; 2022

Cities and Volcanoes Commission, IAVCEI

Although volcanic ashfalls have been largely documented affecting all modes of surface transport, little specific information exists related to volcanic-ash-risks and water transport. In Patagonia Argentina, three recent and widespread ashfall events (associated with the Chaitén 2008, Cordón Caulle 2011-2012, and Calbuco 2015 volcanic eruptions) gravely affected the profuse nautical activity that takes place in the many lakes of the region. By means of thorough field visitations, in-person meetings, guided mechanical inspections, and technical expert advice, we surveyed the effects of these highly disruptive phenomena on the different elements that make up a water transport network. First, we offer a brief reconstruction of the events, narratively compiling details on the most relevant effects of volcanic ash on water transport, the management of the successive volcanic crises, and the response actions undertaken at different coastal sites. Based on these observations, we frame a novel and systematic catalog of volcanic ash impacts particularly on ships, port sites, and shipping activities, accounting not only for primary ash fallouts, but also the drifting of pumice rafts, sedimentation processes, and fluvial and aeolian remobilization events. Plus, we provide a summary and assessment of the most effective mitigation and remediation strategies undertaken, including tephra clean-up actions on the ship and port environments. Finally, in order to better categorize the type and severity of impacts regarding different hazard intensities, we expand on available impact scales from volcanic ash on critical infrastructure, to include more specific details about disruption and physical damage to water transport systems, also evaluating their interrelations with different environmental conditions that controlled impacts’ nature. Our contribution ultimately aims to communicate to emergency managers, policymakers, stakeholders, and the volcanological and nautical communities, the most likely outcomes from explosive volcanic eruptions on shipping, along with best-practice advice for mitigating and remediating potential adversities