STYLES OF PYROCLASTIC ACTIVITY AT KīLAUEA, 2011-2017

Activity at Kīlauea in 2011-2017 helps to delineate the limits of Strombolian explosions and Hawaiian fountaining eruptions. That demarcation has generally been articulated in terms of transient versus sustained activity linked to mechanical decoupling versus partial coupling of exsolved volatiles.

The spectrum of activity at Kīlauea includes events such as ‘low fountains’, ‘gas pistoning’ and ‘spattering’ which fills much of the area between these extremes. We examine here two recent examples. The 5-day-long Kamoamoa eruption in 2011 was a fissure fed event that showed a partial shift from activity resembling ‘rapid’ Strombolian explosions at Etna to sustained but low and unsteady Hawaiian fountaining. Behavior in the Halemaʻumaʻu lava lake has been dominated in recent times by a range of bubble-bursting and spattering activity that alternates with passive outgassing. Variations in the frequency and spatial distribution of bubble-bursting results in a variety do eruptive activity from isolated bubble bursts of duration typically seconds through to episodes of unsteady discharge lasting from minutes to hours.