Lava effusion rates and channel dynamics during the 2018 Kilauea lower East Rift Zone eruption
Abstract
The 2018 eruption of Kīlauea's lower East Rift Zone produced a long-lived channelized lava flow that offered an unprecedented opportunity to track eruptive behavior and channel dynamics over time and space. Comprehensive syn-eruptive data, including video and digital elevation models (DEMs) acquired using small unoccupied aircraft systems (sUAS), airborne lidar and NASA GLISTIN DEMs, air- and ground-based thermal imaging, ground-based video and imagery, and geophysical monitoring, provide detailed observations of the channel morphology and flow velocities through time. These were integrated to derive estimates of lava effusion rate, which is critical for hazards assessment during eruption response. Results show a general increase in eruption rate from ~7 m3/s to ~80 m3/s from early to late May for the whole flow field, and >200 m3/s by mid-June after the eruption had focused at Fissure 8. We also observe short-term (minutes to hours) fluctuations in bulk effusion rate associated with cyclic degassing patterns at the vent and pressure transients caused by caldera collapse events at the volcano's summit. These changes are reflected in the lava channel dynamics, including standing waves and other fluvial phenomena, overflows, crust coverage, and degassing within the channel. In the proximal part of the Fissure 8 channel, standing waves persisted during high effusion rates, from early June until the effective end of the eruption in early August; their wavelengths and the extents of along-flow wave trains varied with flow depth and rate, providing essential information for measurements during the eruption. At the highest flow rates (i.e., during short-term pulsing events), the standing waves disappeared with a transition to chaotic supercritical shooting flow, characterized by low crust coverage and increased degassing. During high flow after caldera collapse events, overflows extended into the distal reaches of the channel, impacting channel and levee evolution and hazards. We analyze trends in effusion rate through time and with distance along flow to understand the sources and implications of these dynamic phenomena for eruption monitoring, lava flow properties and behavior, and hazards.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.V43C0215D
- Keywords:
-
- 8419 Volcano monitoring;
- VOLCANOLOGY;
- 8439 Physics and chemistry of magma bodies;
- VOLCANOLOGY;
- 8440 Calderas;
- VOLCANOLOGY;
- 8488 Volcanic hazards and risks;
- VOLCANOLOGY