73-16 Using Thermochromism to Study the Thermal Evolution of Analogue Lava Flows

Session: Using Volcanic Deposits to Help Us Understand Volcanic and Magmatic Processes (Posters)

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Abstract:

Lava flows are one of the most common volcanic hazards that impact both property and - occasionally - life, yet our understanding of the mechanisms behind their emplacement is still incomplete.

This study aims to provide further insight into the thermal evolution of lava flows, as temperature exerts a key control on their emplacement dynamics. We selected an analogue experimental approach, using polyethylene glycol (PEG) 600 - an organic wax - as the material of choice. PEG is a well-established lava analogue with its temperature-dependent viscosity, a freezing point near room temperature (~18-20°C), and its crust-forming ability. Our experimental setup requires the injection of heated PEG (20-35°C) into chilled water (0-10°C). However, its underwater nature prevents us from directly measuring the surface temperature of the flows.

To overcome this challenge, we constrained the temperature of the flow surface using two thermochromic pigments. The two pigments we selected shift from yellow to red and pink to blue and as they cool, with an activation temperature of 15 °C and 18 °C respectively. The color change with cooling is consistent and predictable, allowing for the calibration of temperature based on color.

So far, we have emplaced 18 PEG flows within the breakout regime, consisting of pillow-like lavas with some rifting. Map-view surface temperatures have been constrained by applying our thermal calibration to video footage of flows. Through a successive viscosity calibration, surface flow viscosity-time maps were also obtained. Additionally, morphological events, such as breakouts or resurfacing, were recorded for all conducted flows, allowing the analyses of their timing, spatial distribution, and frequency.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-6512

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