Localization of volcanic activity: 2. Effects of pre-existing structure

Gaffney, E. S.; Damjanac, Branko; Valentine, Greg A.

doi:10.1016/j.epsl.2007.09.002

Cited by 96 publications

(72 citation statements)

References 43 publications

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“…Indeed the pre-existing faults/fractures have proved to be significantly correlated with the opening of new vents and typically represent a weakness element that may favor the magma ascent (Connor et al, 2000;Calais et al, 2008;Vitale and Isaia, 2014;Mazzarini et al, 2016;Bevilacqua et al, 2017;Tadini et al, 2017). However, several other factors including the fault angle, the magma pressure and the depth of interaction can be relevant too (Gaffney et al, 2007;Le Corvec et al, 2013), but are neglected in the present study. In addition, in order to take into account the influence of other variables not considered or unidentified processes, a uniform probability map inside the caldera is also included.…”

Section: Spatial Probability Distribution Of Vent Openingmentioning

confidence: 68%

The Effects of Vent Location, Event Scale, and Time Forecasts on Pyroclastic Density Current Hazard Maps at Campi Flegrei Caldera (Italy)

et al. 2017

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This study presents a new method for producing long-term hazard maps for pyroclastic density currents (PDC) originating at Campi Flegrei caldera. Such method is based on a doubly stochastic approach and is able to combine the uncertainty assessments on the spatial location of the volcanic vent, the size of the flow and the expected time of such an event. The results are obtained by using a Monte Carlo approach and adopting a simplified invasion model based on the box model integral approximation. Temporal assessments are modeled through a Cox-type process including self-excitement effects, based on the eruptive record of the last 15 kyr. Mean and percentile maps of PDC invasion probability are produced, exploring their sensitivity to some sources of uncertainty and to the effects of the dependence between PDC scales and the caldera sector where they originated. Conditional maps representative of PDC originating inside limited zones of the caldera, or of PDC with a limited range of scales are also produced. Finally, the effect of assuming different time windows for the hazard estimates is explored, also including the potential occurrence of a sequence of multiple events. Assuming that the last eruption of Monte Nuovo (A.D. 1538) marked the beginning of a new epoch of activity similar to the previous ones, results of the statistical analysis indicate a mean probability of PDC invasion above 5% in the next 50 years on almost the entire caldera (with a probability peak of ∼25% in the central part of the caldera). In contrast, probability values reduce by a factor of about 3 if the entire eruptive record is considered over the last 15 kyr, i.e., including both eruptive epochs and quiescent periods.

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Section: Spatial Probability Distribution Of Vent Openingmentioning

confidence: 68%

The Effects of Vent Location, Event Scale, and Time Forecasts on Pyroclastic Density Current Hazard Maps at Campi Flegrei Caldera (Italy)

et al. 2017

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“…Dikes have been found to follow pre-existing faults on both Earth (Gaffney et al, 2007) and Mars (Cole and Andrews-Hanna, 2017). Generally, faults must be within 45° of the preferred angle for dike intrusion in order for the fault capture the dike (Gaffney et al, 2007), though on Mars there is evidence for capture of a dike or sill by a low angle thrust fault (Cole and Andrews-Hanna, 2017).…”

Section: Gravity Gradientsmentioning

confidence: 99%

“…Generally, faults must be within 45° of the preferred angle for dike intrusion in order for the fault capture the dike (Gaffney et al, 2007), though on Mars there is evidence for capture of a dike or sill by a low angle thrust fault (Cole and Andrews-Hanna, 2017). The stresses associated with the central load or mass concentration (mascon) may also play a role in controlling intrusive activity .…”

Section: Gravity Gradientsmentioning

confidence: 99%

Ring faults and ring dikes around the Orientale basin on the Moon

Andrews-Hanna

Head

Johnson

et al. 2018

Icarus

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“…For dilation of misoriented cohesionless fractures, with planes oriented at a high angle to σ 3 , a higher fluid pressure is required to overcome the normal stress acting on their surface (e.g. Gaffney et al, 2007). Importantly, if misoriented planes do not become linked to the fluid network, high fluid overpressures will be relaxed by dilation of preferentially oriented pre-existing structures, or via failure of intact rock (e.g.…”

Section: Dilation Of Pre-existing Fracturesmentioning

confidence: 99%

“…3), as the normal stress acting on these planes exceeds the fluid pressure, preventing dilation (e.g. Gaffney et al, 2007;Gudmundsson, 2011a). Terminated intrusions may inflate against closed fractures if magma supply continues; dilation will be accommodated by local shear along the closed fracture, producing a blunt intrusion tip (Baer, 1991;Stephens et al, 2017).…”

Section: Dilation Of Pre-existing Fracturesmentioning

confidence: 99%

Mechanical models to estimate the paleostress state from igneous intrusions

et al. 2018

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Abstract. Dikes and sills represent an important component of the deformation history in volcanic systems, but unlike dikes, sills are typically omitted from traditional paleostress analyses in tectonic studies. The emplacement of sheet intrusions is commonly associated with Mode I fracturing in a low deviatoric stress state, in which dilation is perpendicular to the fracture plane. Many natural examples of sills and dikes, however, are observed to accommodate minor shear offsets, in addition to a component of dilation. Here we present mechanical models for sills in the San Rafael subvolcanic field, Utah, which use field-based measurements of intrusion attitude and opening angles to constrain the tectonic stress axes during emplacement and the relative magma pressure for that stress state. The sills display bimodal dips to the NE and SW and consistent vertical opening directions, despite variable sill dips. Based on sill attitude and opening angles, we find that the sills were emplaced during a phase of NE-SW horizontal shortening. Calculated principal stress axes are consistent (within ∼ 4 • ) with paleostress results for penecontemporaneous thrust faults in the area. The models presented here can be applied to any set of dilational structures, including dikes, sills, or hydrous veins, and represent a robust method for characterising the paleostress state in areas where other brittle deformation structures (e.g. faults) are not present.

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Localization of volcanic activity: 2. Effects of pre-existing structure

Cited by 96 publications

References 43 publications

The Effects of Vent Location, Event Scale, and Time Forecasts on Pyroclastic Density Current Hazard Maps at Campi Flegrei Caldera (Italy)

The Effects of Vent Location, Event Scale, and Time Forecasts on Pyroclastic Density Current Hazard Maps at Campi Flegrei Caldera (Italy)

Ring faults and ring dikes around the Orientale basin on the Moon

Mechanical models to estimate the paleostress state from igneous intrusions

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