Thursday 29 October, 4 PM CET
DR. SAM POPPE
Abstract: When magma ascends through the Earth’s crust it deforms and displaces the host rocks and ultimately the surface. A fundamental element of volcano monitoring and eruption forecasting is the inversion of that geodetic displacement data to estimate the location, volume, shape and orientation of active magma bodies in the shallow subsurface. The most wide-spread inversion models assume crustal deformation is dominantly elastic, but geological field observations have documented more complex deformation patterns (e.g. Poppe et al., 2020). The models can be improved by integration with other independent geophysical data, but uncertainties on the estimated magma intrusion characteristics remain high and inter-model comparisons often reveal conflicting results. Moreover, active volcanic systems are often found in association with extensional tectonic systems at plate boundaries or continental rift systems. There, it is unclear how magma-induced stress interacts with tectonic extensional stress.
I will briefly present ongoing efforts to analytically invert synthetic surface deformation data from laboratory experiments of magma intrusion that were imaged using X-ray Computed Tomography (Poppe et al., 2019). A recently started FRS-FNRS project aims to build further on this effort of coupling laboratory experiment data and inversion models by studying how magma-induced strain fields interact with extensional tectonic stress regimes in Earth’s mechanically-complex shallow upper crust.
Poppe et al., 2019, An Inside Perspective on Magma Intrusion: Quantifying 3D Displacement and Strain in Laboratory Experiments by Dynamic X-Ray Computed Tomography. Frontiers in Earth Science, 7, 62, https://doi.org/10.3389/feart.2019.00062
Poppe et al., 2020, Structural and Geochemical Interactions Between Magma and Sedimentary Host Rock: The Hovedøya Case, Oslo Rift, Norway. Geochemistry, Geophysics, Geoystems, 21, 3, https://doi.org/10.1029/2019GC008685