Magma reservoir failure and the onset of caldera collapse at Kīlauea Volcano in 2018
Abstract
Caldera-forming eruptions can be among the most hazardous of natural phenomena, yet the architecture of the underlying magmatic storage systems -- and the conditions which trigger reservoir failure and the onset of collapse -- are poorly known. Using remarkable observations from the collapse of a ~0.8 cubic kilometer basaltic caldera at Kīlauea Volcano in 2018, including draining of an active lava lake, we are able to constrain the location, geometry, and total volume of magma stored beneath the caldera, and estimate the changing conditions within this reservoir that preceded failure of its roof rock. The lava lake provided a direct window into evolving pressure in the underlying magmatic system, and we are able to infer that early stages of collapse occurred around the pre-existing eruptive vent when only a small fraction of magma had been evacuated from several cubic km stored at shallow depth beneath the volcano's summit, reducing reservoir pressure by ~15 MPa. Broad-scale episodic failure of the reservoir roof began 12 days later after continued magma outflow had reduced pressure by at least another ~5-10 MPa. These results suggest that, under some conditions, the onset of caldera collapse may begin sooner than previously inferred from theoretical and experimental models. We also place bounds on the geometry of the overlying collapse "piston" which subsided into the reservoir, the rate of magma supply to the volcano's East Rift Zone, and show at high statistical confidence that a significant fraction of magma remained stored in Kīlauea's shallow reservoir at the end of the eruption.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.V43C0216A
- Keywords:
-
- 8419 Volcano monitoring;
- VOLCANOLOGY;
- 8439 Physics and chemistry of magma bodies;
- VOLCANOLOGY;
- 8440 Calderas;
- VOLCANOLOGY;
- 8488 Volcanic hazards and risks;
- VOLCANOLOGY