Work

Tectonic Stress as the Driving Mechanism for Dike Opening in an Oblique Rift Setting: A Deformation Model of the 2021 Fagradalsfjall Dike, Iceland

Year: 2025

Type: article

Abstract: Repeated dike‐intrusions often occur in zones where extensional stress has accumulated. Still, geodetic modeling of observed dike‐induced ground deformation often ignores the contribution of tectonic stress. On the obliquely spreading Reykjanes Peninsula, Iceland, tectonic strain build‐up had been geodetically documented for three decades when a magmatic dike formed at Fagradalsfjall in 2021. We explore the contribution of tectonic stress on dike emplacement in a viscoelastic three‐dimensional Finite‐Element deformation model. Tectonic stress accumulation is initially simulated through plate motion, and later partially released by opening of a segmented rectangular dike. We find that surface deformation can be largely reproduced by releasing 60% of the accumulated tectonic stress. Partial stress release and low magma overpressure are consistent with successive dike intrusions and low‐intensity eruptions in the area. Our model provides an approach to consistently model stress‐release constrained by surface deformation.

Source: Geophysical Research Letters

DOI: 10.1029/2024gl113970

Authors: Sonja H. M. Greiner, Freysteinn Sigmundsson, Halldór Geirsson, Steffi Burchardt, Olivier Galland

Institutions: Uppsala University, Centre of Natural Hazards and Disaster Science, Institute of Earth Sciences, University of Oslo

Language: English

Topic: earthquake and tectonic studies

Subfield: Geophysics

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $3,190

Funders: Uppsala Universitet, Rannís