Dyke-arrest scenarios in extensional regimes: Insights from field observations and numerical models, Santorini, Greece

Abstract

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Relationship Between Active Faulting/Fracturing and Magmatism Around Santorini: Seismic Anisotropy From an Active Source Tomography Experiment

“…Dikes in less tectonically active environments often form circumferential and/or radial patterns (with no preferential orientation) in close proximity to the volcanic edifice (Acocella & Neri, 2009). However, observations of Santorini dikes suggest only a minor component of these effects and a strong preference for the NE‐SW orientation (Browning et al., 2015; Drymoni et al., 2020). The dominance of the NE‐SW direction suggests a strong regional control on dike emplacement (Acocella & Neri, 2009).…”

“…This line is thought to have focused one of the large eruptive phases of the LBA eruption (Pfeiffer, 2001). These two tectono-magmatic lineaments collectively bound: (a) Plinian vents throughout Santorini's history (Druitt, 2014;Hooft et al, 2019); (b) a region of NE-SW diking in the caldera (Fabbro et al, 2013;Browning et al, 2015;Heath et al, 2019;Drymoni et al, 2020); (c) a region of isolated caldera collapse (Hooft et al, 2019); and (d) an upper crustal, NE-SW-elongate magma body (McVey et al, 2020) (Figure 2). NE of Santorini is the Kolumbo volcanic chain, a NE-striking alignment of submarine volcanic cones (e.g., Hooft et al, 2017;Nomikou et al, 2012Nomikou et al, , 2013, the largest of which is Kolumbo Seamount (Hübscher et al, 2015;Nomikou et al, 2016).…”

Field observations and numerical models of a Pleistocene-Holocene feeder dyke swarm associated with a fissure complex to the east of the Tatara-San Pedro-Pellado complex, Southern Volcanic Zone, Chile

“…Several studies have already attempted to estimate the overpressure and source depths of magmas using the aforementioned technique in other volcano tectonic settings (e.g. Ray et al, 2006;Becerril et al, 2013;Browning et al, 2015;Elshaafi and Gudmundsson, 2016;Karaoğlu et al, 2018;Drymoni et al, 2020). Nonetheless, analytical cal culation of magma overpressure and magma source depth is also highly sensitive to dyke aspect ratios and the appropriate choice of crustal stiff ness (Young's modulus).…”

“…Pérez Flores et al, 2016;Sielfeld et al, 2019b), crustal heterogene ities (e.g. Drymoni et al, 2020), load of a volcanic edifice (e.g. Van Wyk De Vries and Merle, 1998;Dahm, 2000;Gudmundsson, 2002;Kervyn et al, 2009;Maccaferri et al, 2011), and the loading effect of crustal res ervoirs (e.g.…”

A Systematic Approach to Mapping Regimes of Earthquake‐Induced Static Stress Changes Acting on Magmatic Pathways

“…Rapid magma transfer through the Earth's crust occurs by flow in self‐propagating sheet intrusions such as dykes (Clemens & Mawer, 1992; Petford et al., 1993, 2000; Rubin, 1995; Ruprecht & Plank, 2013). Magmatic intrusions are generally mode I fractures and so preferentially open parallel to the minimum principal stress direction ( σ 3 ), although they may be influenced by structures or weaknesses in the host rock such as faults, fractures, or layering (Anderson, 1951; Drymoni et al., 2020; Gudmundsson, 2002, 2020; Magee et al., 2013; Nakamura, 1977; Rivalta et al., 2015; Ziv et al., 2000). At the regional level, crustal stress and structure is primarily controlled by plate tectonics (Kearey et al., 2009; Zoback, 1992; Zoback et al., 1989).…”