An unusual patient: 4D X-ray Computed Tomography of analogue magma intrusion experiments

Autor: Sam Poppe, Olivier Galland, Nico Buls, Gert Van Gompel, Eoghan Holohan, Matthias Rosenau, Régis Mourgues, Matthieu Kervyn
Přispěvatelé: Geography, Physical Geography, Faculty of Sciences and Bioengineering Sciences, Medical Imaging, Supporting clinical sciences, Earth System Sciences
Předmět:
Zdroj: Vrije Universiteit Brussel
Popis: Although geophysical observations provide insight into the interaction of shallow magma intrusion and host rock deformation at active volcanic systems, we remain unable to observe these processes directly. Understanding these subsurface processes in all their dimensions, possibly by combining geophysical observables with analytical and numerical models, is nevertheless critical for ultimately forecasting volcanic eruption. We present a novel analogue modeling set-up for magma intrusion in brittle rock, based on X-ray Computed Tomography (XCT). Firstly, we quantified in detail the mechanical behavior of the often-used, but poorly-understood, brittle rock analogue sand-and-plaster mixed at a range of ratios. Secondly, we show how varying the mechanical strength of this brittle host material results in variations of magma analogue intrusion geometries. Thirdly, through medical wide beam XCT, we collected a series of 3D scan images of each entire experiment over a sequence of time increments. We then use this 4D (3D + time) imagery to study (1) the interaction of intrusion growth with deformation (i.e. fault growth and displacement) in the host and (2) the deformation at the model surface. The major novelty of our approach is that it extends 4D monitoring and quantification of deformation beyond the model surface deformation by enabling a full quantification of the entire intrusion and host rock system through time. In the example experiment series, we found that host rock strength controls intrusion geometry and propagation mode, and we document the development of the intrusion-induced system of faults and fractures in the host. Our modeling set-up envisions the interpretation of intrusion-induced deformation and seismicity, and potential validation of analytical and numerical models used in geodesy of active volcanic systems.
Databáze: OpenAIRE