The Geodetic Response to Magma Thermal Modulation During Drilling

Gottsmann, Joachim; Lavallée, Yan (2025): The Geodetic Response to Magma Thermal Modulation During Drilling. Geophysical Research Letters, 52 (16): e2024GL114. ISSN 0094-8276

Abstract

We report surface displacements and gravity changes triggered by thermal modulation of shallow-seated (2 km depth) silicic magma lenses during drilling. 2D plane strain models predict ground subsidence of up to 20 cm and net gravity increases of up to 82 Gal from the thermal contraction of a thin (0.01 aspect ratio) sheet aligned either vertically or horizontally upon rapid (period of months) cooling from magmatic to subcritical temperatures. Application of the models in 2.5D to Krafla caldera (Iceland) where magma was encountered during drilling predicts between 0.1 and 15 cm of ground subsidence and between 7 and 40
Gal of net gravity increase during cooling of the Icelandic deep drilling project well when of coolant (1–7 vol-% of the modeled reservoirs) were lost to the subsurface over a period of 4.5 months. We highlight the importance of magma residence time and thermal fracturing on the efficacy of thermal modulation.

• Doc-Type: Article (LMU)
• Organisational unit (Faculties): 20 Geosciences > Department of Earth and Environmental Sciences
• DFG subject classification of scientific disciplines: Natural sciences
• DFG: Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - 491502892