Magmato-tectonic interactions

Magma intrusions have a strong influence on the deformation of volcanic edifices which is recorded through the use of geophysical tools (e.g., satellites, GPS) [McGuire et al., 1995; Wang et al., 2018]. Understanding these measurements relies on physical models using analogue materials (e.g., [van Wyk de Vries et al., 2000; Norini and Acocella, 2011]) or numerical methods (e.g., [Lisowski, 2006; Casagli et al., 2009]).

Using analogue models, we have shown that magma intrusions within a volcanic edifice can have a strong influence on their internal deformation. Intrusions tend to bulldozed unbuttressed flanks which can on one side clamp tectonic faults, i.e., inhibit tectonic faulting, and on the other side favor movements along detachment within or a decollement at the base of the volcanic edifice (Fig. 1) [Le Corvec and Walter, 2009; Chaput et al., 2014; Le Corvec et al., 2014].

Figure 1: Internal deformation and magmatic activity of oceanic volcanic islands for 1. Hawaii (spreading model with a basal decollement) and 2. La Réunion (non-spreading model with an internal detachment). a. Sketches highlighting the differences in deformation and magmatic activity between Hawaiian and Reunion-like volcanoes. Reworked from Chaput et al. [2014]. b) and c) Analogue experiments and their structural interpretation for a spreading (1b and 1c) and non-spreading model (2b and 2c). Digital image correlation (DIC) technique enables the recognition of shear zones through the analysis of particle displacement. Reworked from Le Corvec and Walter [2009].