Volcanic minerals act as recorders of magma conditions before eruptions
Magma beneath volcanoes is a slushy mix of molten rock and solid crystals, and minerals such as clinopyroxene grow in layers that preserve temperature, depth, and chemical information. Researchers studied crystals from La Palma, including eruptions such as the 2021 Tajogaite event, to reconstruct how magma moved and gathered before erupting. The work suggests these crystals can help improve understanding of volcanic hazards.
Researchers examined clinopyroxene crystals from lava produced by La Palma eruptions in 1712, 1971 and 2021. These minerals grow in successive zones, preserving chemical and physical clues from the magma in which they formed. The crystal interiors point to an older, cooler, crystal-rich reservoir located 18–25 kilometers down, within the upper mantle.
Middle zones indicate that, days to weeks before an eruption, hotter material arrived from greater depth, partially melted existing crystals and mixed the system. Outer zones mark rapid ascent. The 2021 Tajogaite event was La Palma's first eruption in 50 years, lasted nearly three months, destroyed thousands of buildings and displaced over 7,000 people.
This work may sharpen volcano monitoring by linking deep magma movement to crystal records, potentially helping scientists interpret unrest before eruptions. Communities on La Palma and other volcanic islands could benefit if such reconstructions improve hazard assessments, evacuation planning and public warnings. Emergency managers and researchers may gain another line of evidence alongside seismic, ground-deformation and gas data. However, crystal studies cannot predict exact eruption timing or size, so their societal value depends on integration with existing monitoring and clear communication.