Geology & Geophysics Editors' Highlights

Understanding Where and How Magma is Stored

Gravity measurements reveal depth and storage conditions of rhyolitic magma reservoirs beneath the Laguna del Maule volcanic field in Chile.

Source: Journal of Geophysical Research: Solid Earth


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Rhyolitic magmatism fueled some of the most impressive and largest of Earth’s volcanic eruptions. Despite that, our understanding of such events is often incomplete due to the lack of directly observed eruptions. Our efforts are thus frequently directed to the study of their shallow silicic plutonic counterparts to investigate magma dynamics.

The Laguna del Maule volcanic field in Chile is the largest concentration (about 40 km3) of rhyolite ever erupted in the Andes. Numerous post-glacial eruptions have produced large explosions and voluminous lava flows, with the high production rate resulting in approximately 60 meters of surface uplift recorded by paleo-shorelines during the Holocene.

To understand the causes of deformation and assess the likelihood of future eruptions, Trevino et al. [2021] provide a new set of gravity measurements. Data inversion and thermodynamic modelling reveal at least two different magma bodies at shallow levels and at different physical states. The newly discovered, low-density body representing a volatile poor magma with a greater than 30 percent melt proportion reflects the cooling remnant of a once active melt pocket that last erupted 1 to 2 thousand years ago that, upon temperature increase, may be melted, extracted, and erupted again.

Citation: Trevino, S. F., Miller, C. A., Tikoff, B., Fournier, D., & Singer, B. S. [2021]. Multiple, coeval silicic magma storage domains beneath the Laguna del Maule volcanic field inferred from gravity investigations. Journal of Geophysical Research: Solid Earth, 126, e2020JB020850. https://doi.org/10.1029/2020JB020850

—Marco Pistolesi, Associate Editor, JGR: Solid Earth

Text © 2021. The authors. CC BY-NC-ND 3.0
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