Fault reactivation and growth at rift-related calderas
Fault reactivation and growth at rift-related calderas
Caldera collapses are paramount volcano-tectonic features because they form during hazardous explosive volcanic eruptions, they are ideal sites for geothermal development and mineral resources exploitation, and also because they preserve the evidence of the interaction between caldera magmatism and the regional tectonic processes. Despite this, many aspects of the caldera collapse process remain unclear, particularly concerning the interaction between caldera and tectonic related fault systems. We therefore used analogue models 1) to quantify the effect of regional strain on caldera elongation in extensional settings, such as the Main Ethiopian and the Kenya rifts, 2) to describe the effect of regional strain on caldera structures and, vice-versa 3) to document, for the first time, “the other side of the coin”, that is how caldera structures affect the formation of newly forming regional extensional faults. Our models showed that tectonic extension only explains a small proportion (e.g. 13% for the Main Ethiopian Rift) of the elongation of most rift calderas. Furthermore, we showed how specific segments of caldera faults may accommodate regional extension by reactivating, therefore precluding caldera elongation. Finally, we showed how the presence of caldera structures may influence the geometry of newly forming regional normal faults, that display a marked curvature, “faking” caldera ring faults. We have suggested that these “fake” curved caldera ring faults may lead to incorrect estimations of caldera elongation in nature. In addition, such faults may also mislead geothermal fluid exploration, as they are likely disconnected from the caldera structures or the caldera plumbing system, and less likely the locus of hydrothermal fluid flow.
Analogue modelling, Caldera collapse, East African Rift System, Elongation, Fault reactivation, Rifting
Maestrelli, Daniele
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Corti, Giacomo
dce88b12-5b7a-43b1-8a58-5bd1bc13634c
Bonini, Marco
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Keir, Derek
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Facincani, Pietro
1ab1f7f7-5c8e-4e13-9ddc-11d7c676ccd0
Vannucchi, Paola
7c0b6a81-a76a-4357-ac38-6c21e967dbd1
Ventisette, Chiara Del
c1750a3a-3027-47fd-a45c-5f8544eed19a
Montanari, Domenico
f09c8226-1b65-415c-94ab-b6fec5d1dc91
Sani, Federico
6c59b4c4-ecca-4ecc-ba2c-66efa5e5e3df
15 June 2024
Maestrelli, Daniele
1e8d2a80-0847-434e-8433-ed36c650e994
Corti, Giacomo
dce88b12-5b7a-43b1-8a58-5bd1bc13634c
Bonini, Marco
0b661765-6720-4424-9070-a5b6f78df825
Keir, Derek
5616f81f-bf1b-4678-a167-3160b5647c65
Facincani, Pietro
1ab1f7f7-5c8e-4e13-9ddc-11d7c676ccd0
Vannucchi, Paola
7c0b6a81-a76a-4357-ac38-6c21e967dbd1
Ventisette, Chiara Del
c1750a3a-3027-47fd-a45c-5f8544eed19a
Montanari, Domenico
f09c8226-1b65-415c-94ab-b6fec5d1dc91
Sani, Federico
6c59b4c4-ecca-4ecc-ba2c-66efa5e5e3df
Maestrelli, Daniele, Corti, Giacomo, Bonini, Marco, Keir, Derek, Facincani, Pietro, Vannucchi, Paola, Ventisette, Chiara Del, Montanari, Domenico and Sani, Federico
(2024)
Fault reactivation and growth at rift-related calderas.
Earth and Planetary Science Letters, 636, [118700].
(doi:10.1016/j.epsl.2024.118700).
Abstract
Caldera collapses are paramount volcano-tectonic features because they form during hazardous explosive volcanic eruptions, they are ideal sites for geothermal development and mineral resources exploitation, and also because they preserve the evidence of the interaction between caldera magmatism and the regional tectonic processes. Despite this, many aspects of the caldera collapse process remain unclear, particularly concerning the interaction between caldera and tectonic related fault systems. We therefore used analogue models 1) to quantify the effect of regional strain on caldera elongation in extensional settings, such as the Main Ethiopian and the Kenya rifts, 2) to describe the effect of regional strain on caldera structures and, vice-versa 3) to document, for the first time, “the other side of the coin”, that is how caldera structures affect the formation of newly forming regional extensional faults. Our models showed that tectonic extension only explains a small proportion (e.g. 13% for the Main Ethiopian Rift) of the elongation of most rift calderas. Furthermore, we showed how specific segments of caldera faults may accommodate regional extension by reactivating, therefore precluding caldera elongation. Finally, we showed how the presence of caldera structures may influence the geometry of newly forming regional normal faults, that display a marked curvature, “faking” caldera ring faults. We have suggested that these “fake” curved caldera ring faults may lead to incorrect estimations of caldera elongation in nature. In addition, such faults may also mislead geothermal fluid exploration, as they are likely disconnected from the caldera structures or the caldera plumbing system, and less likely the locus of hydrothermal fluid flow.
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Accepted/In Press date: 6 April 2024
e-pub ahead of print date: 18 April 2024
Published date: 15 June 2024
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Publisher Copyright:
© 2024 Elsevier B.V.
Keywords:
Analogue modelling, Caldera collapse, East African Rift System, Elongation, Fault reactivation, Rifting
Identifiers
Local EPrints ID: 489548
URI: http://eprints.soton.ac.uk/id/eprint/489548
ISSN: 0012-821X
PURE UUID: 419371c0-abe7-413c-b81f-1856ba900194
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Date deposited: 26 Apr 2024 17:02
Last modified: 24 May 2024 01:43
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Contributors
Author:
Daniele Maestrelli
Author:
Giacomo Corti
Author:
Marco Bonini
Author:
Pietro Facincani
Author:
Paola Vannucchi
Author:
Chiara Del Ventisette
Author:
Domenico Montanari
Author:
Federico Sani
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