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Deep magma mobilization years before the 2021 CE Fagradalsfjall eruption, Iceland

Published version
Peer-reviewed

Type

Article

Change log

Authors

Kahl, M 
Mutch, EJF 
Morgan, DJ 
Couperthwaite, F 

Abstract

jats:titleAbstract</jats:title> jats:pThe deep roots of volcanic systems play a key role in the priming, initiation, and duration of eruptions. Causative links between initial magmatic unrest at depth and eruption triggering remain poorly constrained. The 2021 CE eruption at Fagradalsfjall in southwestern Iceland, the first deep-sourced eruption on a spreading-ridge system monitored with modern instrumentation, presents an ideal opportunity for comparing geophysical and petrological data sets to explore processes of deep magma mobilization. We used diffusion chronometry to show that deep magmatic unrest in the roots of volcanic systems can precede apparent geophysical eruption precursors by years, suggesting that early phases of magma accumulation and reorganization can occur in the absence of significant increases in shallow seismicity (&lt;7 km depth) or rapid geodetic changes. Closer correlation between geophysical and diffusion age records in the months and days prior to eruption signals the transition from a state of priming to full-scale mobilization in which magma begins to traverse the crust. Our findings provide new insights into the dynamics of near-Moho magma storage and mobilization. Monitoring approaches optimized to detect early phases of magmatic unrest in the lower crust, such as identification and location of deep seismicity, could improve our response to future eruptive crises.</jats:p>

Description

Keywords

37 Earth Sciences, 3703 Geochemistry, 3705 Geology, 3706 Geophysics

Journal Title

Geology

Conference Name

Journal ISSN

0091-7613
1943-2682

Volume Title

Publisher

Geological Society of America
Sponsorship
NERC (NE/W004690/1)