Hooft, EmilieHeath, Benjamin2020-02-272020-02-272020-02-27https://hdl.handle.net/1794/25297In extensional volcanic arcs, tectonic and magmatic processes control the evolution of eruptive centers and their surrounding regions. Faulting, which increases crustal permeability, can focus magmatism and preferentially localize eruptive edifices near intersecting fault zones. In turn, magmatic diking and volcanic edifice growth/collapse can change both the regional and local stress/strain in the crust altering the style and amount of faulting. The relative importance of these magmatic and tectonic processes as well as how these processes coevolve are still poorly known. Here we study magmatic and tectonic interactions at Santorini Volcano, focusing on the localization of magmatism in the highly extended terrain and the subsequent influence of this magmatism on the evolution of tectonic activity. We use the dense PROTEUS active source seismic dataset, collected in a 120 km x 45 km region around the volcano, to perform both P-wave anisotropic traveltime tomography inversions and full waveform inversions, imaging the upper crust down to ∼4 km depth. Integrating our results with the well-studied volcanic and geologic history of Santorini, we show evidence for strong tectonic control on the evolution of Santorini’s magmatic system. In Chapter II and V, this interaction is recorded as i) the alignment of volcanic features parallel to tectonic features, ii) the localization of volcanism within a tectonic basin, and iii) the strong influence of tectono-magmatic lineaments on both regional volcanic evolution and localization iv of caldera collapse. In Chapter III we show that the magnitude of small-scale local faulting is uncorrelated to regions of magmatic activity indicating that magmatism is neither focused in areas of higher fracturing nor is accommodating substantial extensional strain. Rather both magmatism and small-scale faulting are strongly correlated with regional stress. In Chapter IV we hypothesize that the broad distribution of deformation (>40 km wide) currently observed results from magmatic activity. In contrast, a narrower episode of localized deformation (<20 km wide) preceded initiation of regional magmatism. This highlights the impact of regional magmatism on tectonic evolution. This works shows that magmatic and tectonic processes interact on a variety of temporal and spatial scales. This dissertation includes both previously published and co-authored material.en-USAll Rights Reserved.GeophysicsTectonicsTomographyVolcanologyElectronic Thesis or Dissertation