Kīlauea's magma temperature is rising, and it's a cause for concern. The ongoing eruption at the summit of Kīlauea volcano remains paused, but the forecast window for the next episode of high lava fountaining is between April 5th and 15th. This is based on modeling of the slow re-inflation measured at the summit.
The rising temperature of the shallow magma system under the summit is a significant indicator of the eruption's potential. Geochemical analysis of erupted tephra samples over the past decade has revealed that things have been "heating up!" This is not just a figure of speech; the temperature of erupting basaltic lava at our Hawaiian volcanoes is around 1150-1200°C (2100-2190°F).
The USGS Hawaiian Volcano Observatory (HVO) has been monitoring this closely. They've been using magnesium oxide (MgO) values in near-real-time as a geochemical monitoring tool, conducted as part of a cooperative agreement with the Geology Department at the University of Hawai‘i at Hilo. By examining changes in MgO, they can determine whether the magmatic system is cooling down or heating up.
The results are alarming. Over the first 42 episodes of the ongoing lava fountaining eruption in Halema‘uma‘u, the magmatic system has been hotter, with glass MgO higher at 7.0-8.2 weight percent, meaning temperatures are at least 50°F higher (range of 1165-1191°C or 2129-2176°F). This is higher than eruptions from 2018-2023.
The increase in temperature of both glass (liquid component) and olivine shows us that Kīlauea’s shallow magma reservoirs have been heating up over the past decade and continue to show these signals through episode 42. This could mean the episodic activity will continue for some time, or it may reflect somewhat high rates of magma supply to the shallow reservoir beneath Kīlauea’s summit, which could lead to continued episodes or an eruption elsewhere on the volcano.
The HVO's team of interdisciplinary scientists are carefully monitoring Kīlauea to detect any changes to the pattern of episodic eruptions. The laboratory-based work and near-real-time geochemical monitoring is an important perspective that will help detect changes to the thermal state of the system.
In my opinion, this is a critical moment for Kīlauea. The rising magma temperature and the potential for continued episodic activity are a stark reminder of the power and unpredictability of our Hawaiian volcanoes. It's a reminder that we must continue to monitor and study these volcanoes to better understand their behavior and to ensure the safety of those who live and work in their shadow.
