Kīlauea volcano is commonly thought of as an effusive volcano, rightly so as 90% of its 1,500 km2 area is covered by shield lava flows younger than 1,000 years old. Since 1983, lava flows produced by the ongoing PuʻuʻŌʻō eruption have repeatedly impacted surrounding communities and illustrated the unpredictability of long-lived pāhoehoe flows. The management of such crises is, therefore, a delicate task since our lack of understanding of the controlling processes and their feedbacks result in forecasts associated with levels of uncertainties that are orders of magnitudes larger than what is acceptable by authorities. But Kīlauea also has a lesser known explosive history. The summit stratigraphy of the past 2,200 years contains two tephra-dominated units recording century-long periods of un-sustained explosive activity exhibiting a wide range of mechanisms.
These two aspects of the eruptive behaviour of Kīlauea are a key issue of the ongoing 2018 Puna eruption. Should the effusive eruption continue, accurate models of pāhoehoe emplacement will become critically required to provide reliable predictions to civil authorities? In parallel, should the drainage of fresh magma from the summit area towards PuʻuʻŌʻō along the East Rift Zone continue, a new episode of dominantly explosive activity could start around Halema’uma’u crater and produce a different range of hazards.
This talk will present the outcomes of two recent projects located on both sides of the effusive/explosive spectrum of styles at Kīlauea. We will first discuss the emplacement of the 2016-2018 lava flow as inferred from the structure from motion-based visible and thermal imaging of the flow field, and the potential use of this method in an emergency context to inform physical models of flow propagation in real time. Second, we will examine the characterization of deposits of one phase of the most recent explosive episode of Kīlauea and discuss the implications of these finding in the general understanding of the potential range of explosive behaviours. Together, these projects help constrain – and thus reduce the uncertainties of – processes governing eruptions and hazards for present and future eruptions at Kīlauea.