Eruption frequency patterns through time for the current (1999–2018) activity cycle at Volcán de Fuego derived from remote sensing data: Evidence for an accelerating cycle of explosive paroxysms and potential implications of eruptive activity

Abstract

Volcán de Fuego is a stratovolcano in Guatemala that has produced over 50 VEI ≥ 2 eruptions since 1524. After two decades of quiescence, in 1999 Fuego entered a new period of eruptive activity that continues until the present day, characterized by persistent Strombolian activity interspersed with occasional “paroxysmal” eruptions of greater magnitude, the most recent of which occurred in 2018. The land surrounding Fuego accommodates tens of thousands of people, so greater understanding of its eruptive behaviour has important implications for hazard assessment. Nevertheless, there is relatively little literature that studies recent (since 1999) activity of Fuego in detail.Using time-series analysis of remote sensing thermal data during the period 2000–2018 combined with recent bulletin reports, we present evidence for a new eruptive regime beginning in 2015. We find that this regime is defined by a greater frequency of paroxysmal eruptions than in previous years and is characterized by the following sequence of events: (i) effusion of lava flows and increase in summit explosive activity, followed by (ii) an intense eruptive phase lasting 24–48 h, producing a sustained eruptive column, continuous explosions, and occasional pyroclastic flows, followed by (iii) decrease in explosive activity. We discuss various models that explain this increase in paroxysmal frequency, and consider its implications for hazard assessment at Fuego. We advocate the pairing of remote sensing data with monitoring reports for understanding long-term changes in behaviour of poorly-instrumented volcanoes. The results that we present here provide a standard for informed assessment of future episodes of unrest and paroxysmal eruptions of Fuego.