Integration of Petrologic, Geophysical, and Gas Monitoring Data at Kilauea Volcano, Hawaii

Abstract:

Well-quenched, near-vent lava samples taken at weekly to monthly intervals during the past 31 years of near-continuous Kilauea East Rift Zone (ERZ) eruption have yielded an unprecedented temporal record of petrology and geochemistry. Salient petrologic parameters derived from bulk lava major- and trace-element geochemistry, and from microprobe analyses of matrix glasses, phenocrysts, and melt-inclusions, are now incorporated into the USGS Volcano Science Center’s near real-time volcano-monitoring software platform, called the Volcano Analysis and Visualization Environment (VALVE).

 

The petrologic parameters now imported into VALVE for correlation with geophysical and gas data streams are: 1) MgO systematics of bulk lava, glass, and olivine, used to portray pre-eruptive magma temperature and temperature of lava erupted at the vent, 2) incompatible element ratios of bulk lava and glass, used to track either sudden or long-term magma-mixing or magma-source changes , and 3) magmatic sulfur, measured within glass inclusions of olivine, used to infer pre-eruptive volatile content of magma.

Petrologic data in VALVE provides added insight into magmatic processes. For example, since the onset of Kilauea’s summit eruption in 2008, correlations of summit deformation with MgO systematics and magmatic sulfur in coeval summit tephra and ERZ lava, along with their identical incompatible-element signatures, demonstrate summit-to-ERZ magmatic continuity. As constrained by geophysical and geologic observations at both ends of the eruptive plumbing system, changes in petrology of lava erupted at Puu Oo are likely associated with physical maturation of magma pathways along the shallow ERZ conduit, repeated intrusions and systematic over-pressurization during the 2003–2007 surge in magma supply. Two fissure eruptions uprift of Puu Oo in January 1997 and March 2011 also show a strong correlation of geophysical and gas signatures with a petrologic shift to cooler, incompatible-element enriched lava samples, indicating mixing with stored magmas within the ERZ.

This integration of disparate data sets enhances assessments of changing magmatic conditions and enables data-sharing amongst staff scientists monitoring and evaluating hazards associated with ongoing eruptions of Kilauea.