"Strombolian" explosions in Hawai'i

Eruptions labeled "Strombolian" – characterized by spaced discrete explosions that occur when gas pockets burst at the magma free-surface  – represent an endmember of basaltic volcanism, yet the term's applicability outside Stromboli volcano (Italy) itself remains controversial. The occurrence of Strombolian-like activity in diverse settings necessitates a more nuanced approach to classification and characterization. This study presents a quantitative analysis of transient short-lived (seconds to tens of seconds) mafic explosions from two eruptions: the 2011 Kamoamoa eruption of Kīlauea and the 2018 Lower East Rift Zone eruption of Kīlauea (USA, Hawai'i). Ground-based video recordings are the primary data source. Advancements in image processing allow for the efficient analysis of key eruption parameters including explosion frequencies, durations, and repose intervals, as well as 2D particle exit velocities, size distributions, and mass eruption rates and total mass per explosion. Preliminary results revealed that compared to “normal” Strombolian activity at Stromboli, discrete explosions at Kīlauea in 2011 and 2018 were often shorter lived, more closely spaced, and less intense. These findings suggest a spectrum of Strombolian-like behavior, influenced by factors such as magma composition, shallow conduit geometry, and most importantly gas behavior and flux. This diversity of activity challenges the application of the "Strombolian" label and emphasizes the need for quantitative characterization of discrete basaltic explosions outside of Stromboli.