Volcanotectonic interactions between inclined sheets, dykes, and faults at the Santorini Volcano, Greece

Drymoni, Kyriaki; Browning, John; Guðmundsson, Ágúst

doi:10.1016/j.jvolgeores.2021.107294

Cited by 11 publications

(13 citation statements)

References 39 publications

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“…The spatio-temporal evolution of main volcanic centers is controlled by crustal-scale rift zones (Heath et al, 2021;Preine et al, 2022aPreine et al, , 2022c, which are defined by several major faults, and there is alignment along the so-called "Kameni Line" and "Columbus Line"-volcano-tectonic lineaments identified by Heiken and McCoy (1984) and T. H. Druitt et al (1999) (Figure 1b). These lineaments broadly correlate with seismic velocity anomalies in the upper 3 km of the crust (Heath et al, 2019;McVey et al, 2020), as well as the orientations of exposed dyke intrusions onshore (Drymoni et al, 2021(Drymoni et al, , 2022. The Columbus Line (more recently referred to as the "Kolumbo Line," e.g., Heath et al, 2019) can be projected northeastward as a seafloor ridge structure to the Kolumbo edifice, and then further to the northeast as the Kolumbo Volcanic Chain in the Anhydros Basin (Figure 1b).…”

Section: Geological Settingmentioning

confidence: 68%

“…(1999) (Figure 1b). These lineaments broadly correlate with seismic velocity anomalies in the upper 3 km of the crust (Heath et al., 2019; McVey et al., 2020), as well as the orientations of exposed dyke intrusions onshore (Drymoni et al., 2021, 2022). The Columbus Line (more recently referred to as the “Kolumbo Line,” e.g., Heath et al., 2019) can be projected northeastward as a seafloor ridge structure to the Kolumbo edifice, and then further to the northeast as the Kolumbo Volcanic Chain in the Anhydros Basin (Figure 1b).…”

Section: Geological Settingmentioning

confidence: 82%

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Extensional Faulting Around Kolumbo Volcano, Aegean Sea—Relationships Between Local Stress Fields, Fault Relay Ramps, and Volcanism

Crutchley,

Karstens,

Preine

et al. 2023

Tectonics

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The Christiana‐Santorini‐Kolumbo (CSK) volcanic field has hosted more than 100 explosive eruptions in the past 250,000 years, including the 1650 AD eruption of Kolumbo Volcano. Previous studies have established a link between regional tectonics and volcanism in the CSK volcanic field. While 2D seismic reflection data have given valuable insight into regional faulting, detailed fault zone characterization has been precluded by the sparsely spaced profiles. Using 3D seismic reflection data around Kolumbo Volcano, we provide the first 3D characterization of fault zones in the CSK volcanic field. Beneath the volcano’s northwestern flank, and farther to the northwest, normal faults are predominantly NE‐SW trending, with mean fault trends between 044° and 049°. Normal faults beneath the southeastern flank are slightly more north‐oriented, with mean fault trends between 028° and 038°. Our detailed fault zone analysis reveals clear NW‐SE directed extension around the volcano, consistent with published focal mechanisms from microseismicity. The Kolumbo Fault Zone, ∼6 km northwest of Kolumbo Volcano, is characterized by distinct relay ramps between major overstepping normal faults. Regional 2D seismic profiles reveal a previously undocumented volcanic cone directly above the fault zone. Magma ascent to this cone has likely exploited enhanced vertical permeability associated with distributed deformation within a relay ramp. We suggest that fault relay structures may play an important role, over a range of spatial scales, in focusing magma ascent within the CSK volcanic field.

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Section: Geological Settingmentioning

confidence: 68%

Section: Geological Settingmentioning

confidence: 82%

Extensional Faulting Around Kolumbo Volcano, Aegean Sea—Relationships Between Local Stress Fields, Fault Relay Ramps, and Volcanism

Crutchley,

Karstens,

Preine

et al. 2023

Tectonics

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“…Hydraulic fractures are also commonly observed to arrest at contacts between dissimilar layers (Fisher & Warpinski, 2011;Fisher, 2014), and fracture arrest can normally be attributed to Cook-Gordon delamination, stress barrier and/or elastic mismatch (Gudmundsson, 2011). There have also been many studies on the percentage of dykes occupying faults (Gudmundsson, 1983), as well as of dyke-fault interactions (Rubin & Pollard, 1988;Rubin, 1995;Tibaldi, 2015;Drymoni et al 2021).…”

Section: Discussionmentioning

confidence: 99%

“…In this paper, I explore and explain the physics of fluid-driven fracture (hydrofracture) paths. The focus is on magma-driven fractures, particularly on dykes, for the simple reason that numerous well-exposed dykes have been studied in the field where they are seen as having propagated through heterogeneous and layered (anisotropic) crustal segments (Geshi et al 2010(Geshi et al , 2012Galindo & Gudmundsson, 2012;Geshi & Neri, 2014;Drymoni et al 2020Drymoni et al , 2021. Many dyke paths have been studied in detail vertically over hundreds of metres and laterally for kilometres, and traced for tens and, occasionally, hundreds of kilometres.…”

Section: Introductionmentioning

confidence: 99%

The propagation paths of fluid-driven fractures in layered and faulted rocks

Guðmundsson

2022

Geol. Mag.

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Fractures that form when fluid pressure ruptures the rock are referred to as fluid-driven fractures or hydrofractures. These include most dykes, inclined sheets and sills, but also many mineral veins and joints, as well as human-made hydraulic fractures. While considerable field and theoretical work has focused on the geometry and arrest of hydrofractures, how they select their propagation paths, particularly in layered and faulted rocks, has received less attention. Here I propose that of all the possible paths that a given hydrofracture may follow, it selects the path of least (minimum) action as determined by Hamilton’s principle. This means that the selected path is that along which the energy transformed (released) multiplied by the time taken for the propagation is a minimum. Hydrofractures advance their tips/fronts in steps, with a time lag between the fracture front and the fluid front. In the present framework, each step is then controlled by Hamilton’s principle. The results suggest that when the hosting rock body is regarded as homogeneous, isotropic and non-fractured, hydrofracture paths are everywhere perpendicular to the trajectories of the minimum compressive (maximum tensile) principal stress σ3 and follow the trajectories of the maximum principal compressive stress σ1. When applied to layered and faulted rock body, the results indicate that hydrofracture paths may follow existing faults for a while, depending primarily on (1) the dip of the fault (steep faults are the most likely to be used by vertically propagating hydrofractures), and (2) the tensile strength across the fault compared with the tensile strength of the host rock along a path following the direction of σ1. The results suggest that hydrofractures may use faults as parts of their paths primarily if the fault is steeply dipping and with close to zero tensile strength.

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“…For example, the 2000 summit collapse of the Miyakejima volcano in Japan exposed series of arrested dikes and feeder-dikes within the caldera walls (Geshi et al 2002(Geshi et al , 2020. In fact, many caldera walls are ideal for studying the inner workings of volcanoes since the scarps record important information about past magma paths and fault slips (Drymoni et al 2021). More recently, the well-monitored caldera collapse at the summit of Kīlauea (USA) in 2018 (Anderson et al 2019;Tepp 2021) permitted unprecedented temporal coverage of a collapse and allowed frictional properties of the collapse faults to be constrained (Segall and Anderson 2021).…”

Section: Recent Events That Have Shaped Volcanotectonicsmentioning

confidence: 99%

Volcanotectonics: the tectonics and physics of volcanoes and their eruption mechanics

et al. 2022

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The physical processes that operate within, and beneath, a volcano control the frequency, duration, location and size of volcanic eruptions. Volcanotectonics focuses on such processes, combining techniques, data, and ideas from structural geology, tectonics, volcano deformation, physical volcanology, seismology, petrology, rock and fracture mechanics and classical physics. A central aim of volcanotectonics is to provide sufficient understanding of the internal processes in volcanoes so that, when combined with monitoring data, reliable forecasting of eruptions, vertical (caldera) and lateral (landslide) collapses and related events becomes possible. To gain such an understanding requires knowledge of the material properties of the magma and the crustal rocks, as well as the associated stress fields, and their evolution. The local stress field depends on the properties of the layers that constitute the volcano and, in particular, the geometric development of its shallow magma chamber. During this decade an increasing use of data from InSAR, pixel offset and structure-from-motion, as well as dense, portable seismic networks will provide further details on the mechanisms of volcanic unrest, magma-chamber rupture, the propagation of magma-filled fractures (dikes, inclined sheets and sills) and lateral and vertical collapse. Additionally, more use will be made of accurate quantitative data from fossil and active volcanoes, combined with realistic numerical, analytical and machine-learning studies, so as to provide reliable models on volcano behaviour and eruption forecasting.

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Volcanotectonic interactions between inclined sheets, dykes, and faults at the Santorini Volcano, Greece

Cited by 11 publications

References 39 publications

Extensional Faulting Around Kolumbo Volcano, Aegean Sea—Relationships Between Local Stress Fields, Fault Relay Ramps, and Volcanism

Extensional Faulting Around Kolumbo Volcano, Aegean Sea—Relationships Between Local Stress Fields, Fault Relay Ramps, and Volcanism

The propagation paths of fluid-driven fractures in layered and faulted rocks

Volcanotectonics: the tectonics and physics of volcanoes and their eruption mechanics

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