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Many volcanoes exhibit evidence of long-term deformation driven by gravity. This deformation influences the development of magmatic plumbing systems and volcanic vent locations, and it manifests as earthquakes and ground surface motions. Two end-member deformation styles are volcano sagging (flexure) and volcano spreading. Previous modelingstudies indicated that the mechanical and geometric properties of basement rocks below the volcano can control whether a volcano spreads or sags, but these works differed on exactly how. Furthermore, evidence in nature that a volcano may progress from sagging to spreading as it grows has not been tested experimentally. Using Digital Image Correlation (DIC) and a revised scaling approach, we here revisit the classic experiments in which a sand–plaster cone is emplaced upon a basement comprising an upper brittle layer and a lower ductile layer. In a first experiment series, we emplaced the cone instantaneously. By normalizing both brittle and ductile layer thicknesses to cone height, we provide new insight into the dimensionless geometric controls on spreading and sagging. In a novel second experiment series, we emplaced the cone incrementally. We show that as a growing cone migrates through the dimensionless geometric parameter space, its deformation style changes successively in time from sagging to spreading. DIC shows that the horizontal velocity of the cone flank increases linearly or non-linearly during cone construction, but it decreases exponentially after construction ceases. Despite their geometric simplification and the omission of several sedimentological, magmatic, and regional-tectonic processes, our models’ results are compatible with a range of observations of volcanoes on Earth and Mars. In particular, they help to explain: (i) why lithosphere-scale loading results in sagging rather than spreading, and (ii) why ocean island volcanoes of >2-3 km in height develop stellate forms and rift zones.
Bibliografische notaFunding Information:
This manuscript greatly benefited from the comments of four anonymous reviewers and editor C. Petrone. We acknowledge O. Galland and Beanhive for fruitful discussions, and M. Rosenau for access to the DaVis software. During this work EPH received financial support from University College Dublin , GFZ-Potsdam , the European Regional Development Fund project AGEO - Platform for Atlantic Geohazards (Grant code: EAPA_884/2018 ) and the Irish Centre for Research in Applied Geosciences (iCRAG - grant code: 13/RC/2092_P2 ). SP was supported by an Aspirant PhD grant from FWO-Flanders (2014-2019), and since 2021 by ULAM postdoctoral scholarship ( PPN/ULM/2020/1/00067 ) from the Polish National Agency for Academic Exchange (NAWA) and project 2020/37/K/ST10/02447 from the Norwegian Financial Mechanism 2014-2021 (NCN Poland). AD acknowledges an FWO-Flanders Post-doc grant. BvWdF acknowledges funding from the UNESCO International Geosciences Programme (Grant no. 692: Geoheritage for Resilience ). MK acknowledges funding from the Research Foundation – Flanders ( FWO Credit 1505212N and FWO project G029820N ).
© 2023 The Author(s)
Copyright 2023 Elsevier B.V., All rights reserved.
VingerafdrukDuik in de onderzoeksthema's van 'Transition from volcano-sagging to volcano-spreading'. Samen vormen ze een unieke vingerafdruk.
- 2 Afgelopen
1/01/20 → 31/12/23
FWOKN246: Analoge modellering van morfo-structurele processen in actieve vulkaan-tektonische gebieden.
1/01/12 → 31/12/12