The longevity of lava dome eruptions: analysis of the global DomeHaz database

Abstract:

The likely duration of ongoing volcanic eruptions is a topic of great interest to volcanologists, volcano observatories, and communities near volcanoes. Lava dome forming eruptions can last from days to centuries, and can produce violent, difficult-to-forecast activity including vulcanian to plinian explosions and pyroclastic density currents. Periods of active dome extrusion are often interspersed with periods of relative quiescence, during which extrusion may slow or pause altogether, but persistent volcanic unrest continues. This contribution focuses on the durations of these longer-term unrest phases, hereafter eruptions, that include periods of both lava extrusion and quiescence.

A new database of lava dome eruptions, DomeHaz, provides characteristics of 228 eruptions at 127 volcanoes; for which 177 have duration information. We find that while 78% of dome-forming eruptions do not continue for more than 5 years, the remainder can be very long-lived. The probability distributions of eruption durations are shown to be heavy-tailed and vary by magma composition. For this reason, eruption durations are modeled with generalized Pareto distributions whose governing parameters depend on each volcano’s composition and eruption duration to date.

Bayesian predictive distributions and associated uncertainties are presented for the remaining duration of ongoing eruptions of specified composition and duration to date. Forecasts of such natural events will always have large uncertainties, but the ability to quantify such uncertainty is key to effective communication with stakeholders and to mitigation of hazards. Projections are made for the remaining eruption durations of ongoing eruptions, including those at Soufrière Hills Volcano, Montserrat and Sinabung, Indonesia.

This work provides a quantitative, transferable method and rationale on which to base long-term planning decisions for dome forming volcanoes of different compositions, regardless of the quality of an individual volcano’s eruptive record, by leveraging a global database.