Thermally-assisted Magma Emplacement Explains Restless Calderas

Area of Science:

• Geosciences
• Volcanology
• Geophysics

Background:

• Calderas exhibit centuries-long unrest, likely magma-induced, but dynamics remain poorly understood.
• Campi Flegrei caldera in Italy has experienced multiple significant unrest episodes in recent decades.

Purpose of the Study:

• To investigate the mechanisms driving the persistent unrest in restless calderas.
• To understand the dynamics of magma-induced deformation and thermal evolution in Campi Flegrei.

Main Methods:

• Interpretation of ground deformation data.
• Development and application of thermal models for Campi Flegrei.
• Analysis of volcanic rock compositions to infer magma history.

Main Results:

• Inflation and deflation of magmatic sources at consistent locations explain observed deformation since 1538 AD.
• A shallow magma intrusion ~3,000 years prior to the last eruption created a thermal anomaly.
• This thermal anomaly assisted repeated magma emplacement, maintaining a hot crust.

Conclusions:

• The thermal anomaly from past intrusions is key to understanding persistent magma sources and unrest in Campi Flegrei.
• This model of thermally-assisted unrest may explain the behavior of other restless calderas globally.
• The findings also account for the complex magmatic processes (crystallization, re-melting, mixing) observed in volcanic rocks.