Volcanic ash is an excellent archetype of an ‘extensive hazard’. Ash fall occurs frequently and intermittently during volcanic eruptions, and populations in close proximity to persistently-active volcanoes report ash impacts and distribution that have complex spatial patterns. This is reflected in high-resolution modelling of ash dispersion that integrates local atmospheric and topographic effects. This paper reviews three case studies of long-lasting eruptions in the Caribbean and Ecuador to highlight the extensive characteristics of ash eruption, deposition, and impacts. Over the long term, attritional effects of volcanic ash create negative impacts on livelihood trajectories via loss of income and nutrition from agriculture, and damage to and increased maintenance of critical infrastructure. There are also benefits: communities report that over short time periods following eruptions, there is often increased agricultural productivity.
Recognition of the extensive nature of volcanic ash impacts has direct implications for disaster risk reduction policy and practice. These include the need to: anticipate long-lasting costs of relief and potentially severe impacts on people’s wellbeing; plan flexibly to respond to high spatial and temporal variability in impacts; and to be cognisant of communities’ adaptations and actions to maintain livelihoods when undertaking external interventions. This work highlights that collaborations between populations at risk, scientists and managers of risk can create pragmatic solutions that mitigate the most serious impacts and exploit the benefits of volcanic ash.
This paper is a contribution to the 2019 edition of the Global Assessment Report on Disaster Risk Reduction (GAR 2019).
To cite this paper:
Phillips, J. et al. Dynamic and extensive risk arising from volcanic ash impacts on agriculture. Contributing Paper to GAR 2019