Superheated Magma Delays Crystal Growth, Influencing Eruption Style

Scientists have discovered that extremely hot magma can significantly alter how a volcanic eruption unfolds. This phenomenon, known as superheating, can prevent the formation of crystals within magma, allowing it to remain fluid for longer periods as it ascends.

An international research team, led by The University of Manchester, analyzed magma from the 2021 Tajogaite eruption on La Palma, Spain. Their findings suggest that superheating dissolves tiny existing crystals that typically act as nucleation sites for new crystal growth. This process also reorganizes the magma's microscopic structure, making it less conducive to new crystal development.

Researchers recreated volcanic conditions in a laboratory using magma from the Tajogaite eruption. They observed crystal formation in real time using synchrotron X-ray microtomography. Magma that was not superheated began forming crystals within approximately 20 minutes. In contrast, strong superheating delayed crystal formation for over eight hours.

These delays in crystallization can keep magma relatively fluid, enabling it to rise rapidly to the surface. This rapid ascent can lead to dramatic lava fountains. If crystals form earlier, the magma becomes thicker and more viscous, resulting in a slower rise. This slower movement allows volcanic gases to escape, potentially leading to a gentler, effusive eruption.

This research provides new insights into how magma's temperature history affects crystallization before and during an eruption. Understanding the role of superheating could help volcanologists better interpret monitoring data. It may also improve forecasts of volcanic eruption behavior.

The study's results were published in *Nature Communications*.