USGS publishes study on Kīlauea lava fountain geochemistry

The US Geological Survey published a new paper Tuesday on the geochemistry of lava fountains at Kīlauea volcano in Hawaii. The paper was led by the USGS Hawaiian Volcano Observatory and tracks the geochemistry of the first year of lava fountains from episodes 1 through 39 of the ongoing episodic eruption in Halema'uma'u at the summit of Kīlauea, which began December 23, 2024.

The agency said the paper found no significant geochemical changes during episodes that might be related to the range of observed lava fountain heights or episode durations.

According to the report, there has been variable but clear geochemical and petrologic influence of the still-molten Halema'uma'u lava lake interior on the compositions of erupted lava fountain material.

The agency said the magmas driving the eruption were stored and sourced from the shallow 1 to 2 kilometer Halema'uma'u reservoir.

A new magma composition arrived within a few weeks of the eruption onset, with elevated incompatible elements in addition to a higher MgO signature, the report said.

Kīlauea's shallow reservoir system is heating up, with higher bulk MgO and systematically increasing olivine Fo contents in the low-Fo population, according to the agency.

The paper is titled Petrologic and geochemical characterization of the first year of the 2024-ongoing episodic Halema'uma'u eruption of Kīlauea (Episodes 1-39) and is available to read online through ScienceDirect.