The gravimetric picture of magmatic and hydrothermal sources driving hybrid unrest on Tenerife in 2004/5

Prutkin, I.; Vajda, P.; Gottsmann, Joachim

doi:10.1016/j.jvolgeores.2014.06.003

Cited by 11 publications

(19 citation statements)

References 25 publications

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“…This study revealed that the methodology is applicable to time-lapse gravity changes observed during unrest or volcanic activity. The second study [31] was performed on gravity changes observed during the 2004/5 unrest on Tenerife [15]. This study manifested the true potential of the methodology.…”

Section: Prutkin Inversion Methodologymentioning

confidence: 95%

“…The methodology was originally developed and applied to structural geophysical studies at global, regional, and even local scales [50][51][52][53]. We [31,54] have applied it recently to temporal gravity changes and the results seem promising.…”

Section: Prutkin Inversion Methodologymentioning

confidence: 99%

“…The methodology consists of the following blocks or algorithms: (a) trend removal (optional), where trend is defined as a 2D harmonic function and computed from the input data; (b) decomposition into shallow/deep (or more depth interval) field components (optional) using a triple harmonic continuation numerical procedure; (c) 3D line segments approximation of the sources, where the gravitational effect of these sources approximates the input gravity data; (d) field decomposition based on the individual or grouped line segment effects; and (e) solutions in terms of potato-shaped (closed compact star-convex) source bodies and/or contact surfaces (density discontinuity interfaces). All of these data processing and inversion steps are described mathematically in [31,53]. When the methodology is applied to (time-lapse) gravity changes instead of gravity anomalies, the represent subsurface time-lapse (temporal) density changes instead of density anomalies.…”

Section: Prutkin Inversion Methodologymentioning

confidence: 99%

“…Some interpretations favor a magma intrusion process (e.g., [2,19,25,26]), whereas the opposing ones prefer a hydrothermal reasoning (e.g., [11,14,[27][28][29]). Nat-urally, these two source processes may act simultaneously complementing each other, being referred to as hybrid unrest (e.g., [15,30,31]).…”

Section: Decomposition Of Superimposed Gravity Signalsmentioning

confidence: 99%

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Recent Developments and Trends in Volcano Gravimetry

Vajda¹

2016

Updates in Volcanology - From Volcano Modelling to Volcano Geology

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The aim of this chapter is to take a look at some developments and new trends in volcano gravimetry. First, we will review the objectives of the research work within this subfield of geophysics, discuss the data and methods it uses, and outline the outputs it strives for. Then, we will turn our attention to three areas where innovative approaches possibly can forward this field of study. The first has to do with the coupling between vertical deformations of the topographic surface elevation changes and the observed gravity changes or, in other words, with the removal of the deformation-induced gravimetric signal from the observed gravity changes to obtain the net gravity changes caused by volcanic signals. The second and third areas regard the inversion of the observed gravity changes and deal with two recently or newly developed inversion approaches that both are characterized by the ability to produce a suite of diverse solutions that can be analyzed and discriminated based on additional independent constraints stemming from other earth science disciplines or from the cognition of the interpreter. With this in mind, the final goal is a better understanding of the mechanisms and processes of volcanic unrest or reawakening of a volcano and forecasting the threat of consequent activity and impacts.Keywords: temporal gravity changes, deformation, surface displacements, inversion, interpretation, volcanic unrest . Introduction "ctive and dormant volcanoes cover the face of the earth more plentifully than we usually percept. Their proximity is often richly inhabited by residents or visited by tourists, which gives rise to a tight link between the prosperity, wealth and health, and even the fate of those people and a volcano. "s a natural consequence, the knowledge about the possible volcanic threat is of high demand. Our knowledge, however, of volcanic processes and behavior is far from © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. complete or ideal. There is a lot of room for earth science endeavors and research efforts to contribute to this knowledge. Here, we take a look at how much can a specific earth science discipline gravimetry contribute to this topic. Gravimetry is a discipline overlapping the fields of geophysics, geodesy, and geodynamics that deals with the geometry, properties, and changes of the earth gravity field by means of its observation, analysis, and interpretation.When considering volcanic hazards, the knowledge of the following elements is essential the geological past of a volcano, the geological structure of a volcano and its tectonic setting, and the subsurface processes taking place inside a restless or awakening volcano or deep underneath it within the crust and upper mantle. None of these three elements can be observed directly. The ...

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Section: Prutkin Inversion Methodologymentioning

confidence: 95%

Section: Prutkin Inversion Methodologymentioning

confidence: 99%

Section: Prutkin Inversion Methodologymentioning

confidence: 99%

Section: Decomposition Of Superimposed Gravity Signalsmentioning

confidence: 99%

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Recent Developments and Trends in Volcano Gravimetry

Vajda¹

2016

Updates in Volcanology - From Volcano Modelling to Volcano Geology

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“…During the volcanic unrest of 2004-2005, spatio-temporal gravity changes were observed (Gottsmann et al, 2006), at 14 benchmarks of the rapid reaction CVC network, accompanied by no statistically significant areal surface deformations (within the average precision of the elevation control of ±3 cm). Since the area did not experience widespread ground deformation, there was no need to correct for the deformation-induced topographic effects when inverting and interpreting the gravity changes of the unrest (Gottsmann et al, 2006;Prutkin et al, 2014). Only a few benchmarks experienced local vertical displacements denoted by Gottsmann et al (2006) as site effects.…”

Section: Synthetic Case Study: Central Volcanic Complex Of Tenerifementioning

confidence: 99%

Deformation induced topographic effects in inversion of temporal gravity changes: First look at Free Air and Bouguer terms

Vajda¹,

Pavol²,

Papčo³

et al. 2015

Contributions to Geophysics and Geodesy

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We review here the gravitational effects on the temporal (time-lapse) gravity changes induced by the surface deformation (vertical displacements). We focus on two terms, one induced by the displacement of the benchmark (gravity station) in the ambient gravity field, and the other imposed by the attraction of the masses within the topographic deformation rind. The first term, coined often the Free Air Effect (FAE), is the product of the vertical gradient of gravity (VGG) and the vertical displacement of the benchmark. We examine the use of the vertical gradient of normal gravity, typically called the theoretical or normal Free Air Gradient (normal FAG), as a replacement for the true VGG in the FAE, as well as the contribution of the topography to the VGG. We compute a topographic correction to the normal FAG, to offer a better approximation of the VGG, and evaluate its size and shape (spatial behavior) for a volcanic study area selected as the Central Volcanic Complex (CVC) on Tenerife, where this correction reaches 77% of the normal FAG and varies rapidly with terrain. The second term, imposed by the attraction of the vertically displaced topo-masses, referred to here as the Topographic Deformation Effect (TDE) must be computed by numerical evaluation of the Newton volumetric integral. As the effect wanes off quickly with distance, a high resolution DEM is required for its evaluation. In practice this effect is often approximated by the planar or spherical Bouguer deformation effect (BDE). By a synthetic simulation at the CVC of Tenerife we show the difference between the rigorously evaluated TDE and its approximation by the planar BDE. The complete effect, coined here the Deformation Induced Topographic Effect (DITE) is the sum of FAE and TDE. Next we compare by means of synthetic simulations the DITE with two approximations of DITE typically used in practice: one amounting only to the first term in which the VGG is approximated by normal FAG, the other adopting a Bouguer corrected normal FAG (BCFAG).

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The Ups and Downs of Volcanic Unrest: Insights from Integrated Geodesy and Numerical Modelling

Hickey

Gottsmann

Mothes

et al. 2017

Advances in Volcanology

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Volcanic eruptions are often preceded by small changes in the shape of the volcano. Such volcanic deformation may be measured using precise surveying techniques and analysed to better understand volcanic processes. Complicating the matter is the fact that deformation events (e.g., inflation or deflation) may result from magmatic, non-magmatic or mixed/hybrid sources. Using spatial and temporal patterns in volcanic deformation data and mathematical models it is possible to infer the location and strength of the subsurface driving mechanism. This can provide essential information to inform hazard assessment, risk mitigation and eruption forecasting. However, most generic models oversimplify their representation of the crustal conditions in which the deformation source resides. We present work from a selection of studies that employ advanced numerical models to interpret deformation and gravity data. These incorporate crustal heterogeneity, topography, viscoelastic rheology and the influence of temperature, to constrain unrest source parameters at Uturuncu (Bolivia), Cotopaxi (Ecuador), Soufrière Hills (Montserrat), and Teide (Tenerife) volcanoes. Such model complexities are justified by

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The gravimetric picture of magmatic and hydrothermal sources driving hybrid unrest on Tenerife in 2004/5

Cited by 11 publications

References 25 publications

Recent Developments and Trends in Volcano Gravimetry

Recent Developments and Trends in Volcano Gravimetry

Deformation induced topographic effects in inversion of temporal gravity changes: First look at Free Air and Bouguer terms

The Ups and Downs of Volcanic Unrest: Insights from Integrated Geodesy and Numerical Modelling

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