Ground Deformation After a Caldera Collapse: Contributions of Magma Inflow and Viscoelastic Response to the 2015–2018 Deformation Field Around Bárðarbunga, Iceland

Siqi Li; Freysteinn Sigmundsson; Vincent Drouin; Michelle M. Parks; Benedikt G. Ófeigsson; Kristín Jónsdóttir; Ronni Grapenthin; Halldór Geirsson; Andrew Hooper; Sigrún Hreinsdóttir

doi:10.1029/2020JB020157

Ground Deformation After a Caldera Collapse: Contributions of Magma Inflow and Viscoelastic Response to the 2015–2018 Deformation Field Around Bárðarbunga, Iceland

Siqi Li, Freysteinn Sigmundsson, Vincent Drouin, Michelle M. Parks, Benedikt G. Ófeigsson, Kristín Jónsdóttir, Ronni Grapenthin, Halldór Geirsson, Andrew Hooper, Sigrún Hreinsdóttir

University of Iceland

Research output: Contribution to journal › Article › peer-review

Abstract

Improvement of our understanding of the role of ground deformation due to viscoelastic relaxation following eruptions is important, as the generated signals can resemble renewed magma inflow. We study post-eruptive unrest at the subglacial Bárðarbunga volcano, Iceland, after a caldera collapse and major magma drainage in 2014–2015. Elevated seismicity began about 6 months after the eruption ended, including nine M_lw > 4.5 earthquakes. Global Navigation Satellite System and Sentinel-1 Interferometric Synthetic Aperture Radar geodesy are applied to evaluate post-eruptive ground deformation from 2015 to 2018. Horizontal velocities locally exceed 10 cm/year and rapidly decay with distance away from the caldera. We explore two end-member models and their combination to explain the post-eruptive deformation field: 1) viscoelastic relaxation caused by the co-eruptive caldera collapse and magma withdrawal, and 2) renewed magma inflow. We find parameter combinations for each model that explain the observed ground deformation. The purely viscoelastic relaxation model, consisting of a half-space composed of a 7-km thick elastic layer on top of a viscoelastic layer with a viscosity of 3.0 × 10¹⁸ Pa s reproduces broadly the observations. A simple magma inflow model consisting of a single point source with an inflow rate of 1 × 10⁷ m³/year at 0.7 km depth broadly fits the observations, but may be unrealistic. A more elaborate model of magma inflow into a 10-km deep sill combined with slip on the caldera ring fault explains the observations well. Our results suggest that the co-eruptive deformation field is likely influenced by viscoelastic relaxation, renewed magma inflow, or a combination of both processes.

Original language	English
Article number	e2020JB020157
Journal	Journal of Geophysical Research: Solid Earth
Volume	126
Issue number	3
DOIs	https://doi.org/10.1029/2020JB020157
Publication status	Published - Mar 2021

Bibliographical note

Funding Information: The authors thank staff at the Institute of Earth Sciences at University of Iceland and the Icelandic Meteorological Office, in particular Páll Einarsson, Gro Birkefeldt Møller Pedersen, and Ásta Rut Hjartardóttir, as well as Vala Hjörleifsdóttir from Reykjavík Energy, for extensive discussions with us about the research presented here. The authors thank Sveinbjörn Steinþórsson who provided important technical help for the campaign GNSS fieldwork and Cécile Adélie Ducrocq for advise on GNSS data processing. The authors thank Amandine Auriac who provided the Glacial Isostatic Adjustment model grid (Auriac, 2014 ). The authors thank the Research Fund of University of Iceland for funding for the Ph.D. work of the first author (S. Li), which this research is a part of. Partial financial support from the H2020 project EUROVOLC funded by the European Commission is acknowledged (grant number 731070). R.G. acknowledges partial support for this work through NSF grant EAR‐1464546. The authors thank the reviewers for comments that helped us to greatly improve the manuscript. Funding Information: The authors thank staff at the Institute of Earth Sciences at University of Iceland and the Icelandic Meteorological Office, in particular P?ll Einarsson, Gro Birkefeldt M?ller Pedersen, and ?sta Rut Hjartard?ttir, as well as Vala Hj?rleifsd?ttir from Reykjav?k Energy, for extensive discussions with us about the research presented here. The authors thank Sveinbj?rn Stein??rsson who provided important technical help for the campaign GNSS fieldwork and C?cile Ad?lie Ducrocq for advise on GNSS data processing. The authors thank Amandine Auriac who provided the Glacial Isostatic Adjustment model grid (Auriac,?2014). The authors thank the Research Fund of University of Iceland for funding for the Ph.D. work of the first author (S. Li), which this research is a part of. Partial financial support from the H2020 project EUROVOLC funded by the European Commission is acknowledged (grant number 731070). R.G. acknowledges partial support for this work through NSF grant EAR-1464546. The authors thank the reviewers for comments that helped us to greatly improve the manuscript. Publisher Copyright: © 2021. American Geophysical Union. All Rights Reserved.

Other keywords

Bárðarbunga
GNSS
InSAR
viscoelasticity
volcanic unrest

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10.1029/2020JB020157

Cite this

Li, S., Sigmundsson, F., Drouin, V., Parks, M. M., Ófeigsson, B. G., Jónsdóttir, K., Grapenthin, R., Geirsson, H., Hooper, A., & Hreinsdóttir, S. (2021). Ground Deformation After a Caldera Collapse: Contributions of Magma Inflow and Viscoelastic Response to the 2015–2018 Deformation Field Around Bárðarbunga, Iceland. Journal of Geophysical Research: Solid Earth, 126(3), Article e2020JB020157. https://doi.org/10.1029/2020JB020157

@article{13b5b1c719714d6bbf77acc96bff4a1c,

title = "Ground Deformation After a Caldera Collapse: Contributions of Magma Inflow and Viscoelastic Response to the 2015–2018 Deformation Field Around B{\'a}r{\dh}arbunga, Iceland",

abstract = "Improvement of our understanding of the role of ground deformation due to viscoelastic relaxation following eruptions is important, as the generated signals can resemble renewed magma inflow. We study post-eruptive unrest at the subglacial B{\'a}r{\dh}arbunga volcano, Iceland, after a caldera collapse and major magma drainage in 2014–2015. Elevated seismicity began about 6 months after the eruption ended, including nine Mlw > 4.5 earthquakes. Global Navigation Satellite System and Sentinel-1 Interferometric Synthetic Aperture Radar geodesy are applied to evaluate post-eruptive ground deformation from 2015 to 2018. Horizontal velocities locally exceed 10 cm/year and rapidly decay with distance away from the caldera. We explore two end-member models and their combination to explain the post-eruptive deformation field: 1) viscoelastic relaxation caused by the co-eruptive caldera collapse and magma withdrawal, and 2) renewed magma inflow. We find parameter combinations for each model that explain the observed ground deformation. The purely viscoelastic relaxation model, consisting of a half-space composed of a 7-km thick elastic layer on top of a viscoelastic layer with a viscosity of 3.0 × 1018 Pa s reproduces broadly the observations. A simple magma inflow model consisting of a single point source with an inflow rate of 1 × 107 m3/year at 0.7 km depth broadly fits the observations, but may be unrealistic. A more elaborate model of magma inflow into a 10-km deep sill combined with slip on the caldera ring fault explains the observations well. Our results suggest that the co-eruptive deformation field is likely influenced by viscoelastic relaxation, renewed magma inflow, or a combination of both processes.",

keywords = "B{\'a}r{\dh}arbunga, GNSS, InSAR, viscoelasticity, volcanic unrest",

author = "Siqi Li and Freysteinn Sigmundsson and Vincent Drouin and Parks, \{Michelle M.\} and {\'O}feigsson, \{Benedikt G.\} and Krist{\'i}n J{\'o}nsd{\'o}ttir and Ronni Grapenthin and Halld{\'o}r Geirsson and Andrew Hooper and Sigr{\'u}n Hreinsd{\'o}ttir",

note = "Funding Information: The authors thank staff at the Institute of Earth Sciences at University of Iceland and the Icelandic Meteorological Office, in particular P{\'a}ll Einarsson, Gro Birkefeldt M{\o}ller Pedersen, and {\'A}sta Rut Hjartard{\'o}ttir, as well as Vala Hj{\"o}rleifsd{\'o}ttir from Reykjav{\'i}k Energy, for extensive discussions with us about the research presented here. The authors thank Sveinbj{\"o}rn Stein{\th}{\'o}rsson who provided important technical help for the campaign GNSS fieldwork and C{\'e}cile Ad{\'e}lie Ducrocq for advise on GNSS data processing. The authors thank Amandine Auriac who provided the Glacial Isostatic Adjustment model grid (Auriac, 2014 ). The authors thank the Research Fund of University of Iceland for funding for the Ph.D. work of the first author (S. Li), which this research is a part of. Partial financial support from the H2020 project EUROVOLC funded by the European Commission is acknowledged (grant number 731070). R.G. acknowledges partial support for this work through NSF grant EAR‐1464546. The authors thank the reviewers for comments that helped us to greatly improve the manuscript. Funding Information: The authors thank staff at the Institute of Earth Sciences at University of Iceland and the Icelandic Meteorological Office, in particular P?ll Einarsson, Gro Birkefeldt M?ller Pedersen, and ?sta Rut Hjartard?ttir, as well as Vala Hj?rleifsd?ttir from Reykjav?k Energy, for extensive discussions with us about the research presented here. The authors thank Sveinbj?rn Stein??rsson who provided important technical help for the campaign GNSS fieldwork and C?cile Ad?lie Ducrocq for advise on GNSS data processing. The authors thank Amandine Auriac who provided the Glacial Isostatic Adjustment model grid (Auriac,?2014). The authors thank the Research Fund of University of Iceland for funding for the Ph.D. work of the first author (S. Li), which this research is a part of. Partial financial support from the H2020 project EUROVOLC funded by the European Commission is acknowledged (grant number 731070). R.G. acknowledges partial support for this work through NSF grant EAR-1464546. The authors thank the reviewers for comments that helped us to greatly improve the manuscript. Publisher Copyright: {\textcopyright} 2021. American Geophysical Union. All Rights Reserved.",

year = "2021",

month = mar,

doi = "10.1029/2020JB020157",

language = "English",

volume = "126",

journal = "Journal of Geophysical Research: Solid Earth",

issn = "2169-9313",

publisher = "John Wiley and Sons Inc.",

number = "3",

}

Li, S, Sigmundsson, F, Drouin, V, Parks, MM, Ófeigsson, BG, Jónsdóttir, K, Grapenthin, R, Geirsson, H, Hooper, A & Hreinsdóttir, S 2021, 'Ground Deformation After a Caldera Collapse: Contributions of Magma Inflow and Viscoelastic Response to the 2015–2018 Deformation Field Around Bárðarbunga, Iceland', Journal of Geophysical Research: Solid Earth, vol. 126, no. 3, e2020JB020157. https://doi.org/10.1029/2020JB020157

Ground Deformation After a Caldera Collapse: Contributions of Magma Inflow and Viscoelastic Response to the 2015–2018 Deformation Field Around Bárðarbunga, Iceland. / Li, Siqi; Sigmundsson, Freysteinn; Drouin, Vincent et al.
In: Journal of Geophysical Research: Solid Earth, Vol. 126, No. 3, e2020JB020157, 03.2021.

Research output: Contribution to journal › Article › peer-review

TY - JOUR

T1 - Ground Deformation After a Caldera Collapse

T2 - Contributions of Magma Inflow and Viscoelastic Response to the 2015–2018 Deformation Field Around Bárðarbunga, Iceland

AU - Li, Siqi

AU - Sigmundsson, Freysteinn

AU - Drouin, Vincent

AU - Parks, Michelle M.

AU - Ófeigsson, Benedikt G.

AU - Jónsdóttir, Kristín

AU - Grapenthin, Ronni

AU - Geirsson, Halldór

AU - Hooper, Andrew

AU - Hreinsdóttir, Sigrún

N1 - Funding Information: The authors thank staff at the Institute of Earth Sciences at University of Iceland and the Icelandic Meteorological Office, in particular Páll Einarsson, Gro Birkefeldt Møller Pedersen, and Ásta Rut Hjartardóttir, as well as Vala Hjörleifsdóttir from Reykjavík Energy, for extensive discussions with us about the research presented here. The authors thank Sveinbjörn Steinþórsson who provided important technical help for the campaign GNSS fieldwork and Cécile Adélie Ducrocq for advise on GNSS data processing. The authors thank Amandine Auriac who provided the Glacial Isostatic Adjustment model grid (Auriac, 2014 ). The authors thank the Research Fund of University of Iceland for funding for the Ph.D. work of the first author (S. Li), which this research is a part of. Partial financial support from the H2020 project EUROVOLC funded by the European Commission is acknowledged (grant number 731070). R.G. acknowledges partial support for this work through NSF grant EAR‐1464546. The authors thank the reviewers for comments that helped us to greatly improve the manuscript. Funding Information: The authors thank staff at the Institute of Earth Sciences at University of Iceland and the Icelandic Meteorological Office, in particular P?ll Einarsson, Gro Birkefeldt M?ller Pedersen, and ?sta Rut Hjartard?ttir, as well as Vala Hj?rleifsd?ttir from Reykjav?k Energy, for extensive discussions with us about the research presented here. The authors thank Sveinbj?rn Stein??rsson who provided important technical help for the campaign GNSS fieldwork and C?cile Ad?lie Ducrocq for advise on GNSS data processing. The authors thank Amandine Auriac who provided the Glacial Isostatic Adjustment model grid (Auriac,?2014). The authors thank the Research Fund of University of Iceland for funding for the Ph.D. work of the first author (S. Li), which this research is a part of. Partial financial support from the H2020 project EUROVOLC funded by the European Commission is acknowledged (grant number 731070). R.G. acknowledges partial support for this work through NSF grant EAR-1464546. The authors thank the reviewers for comments that helped us to greatly improve the manuscript. Publisher Copyright: © 2021. American Geophysical Union. All Rights Reserved.

PY - 2021/3

Y1 - 2021/3

N2 - Improvement of our understanding of the role of ground deformation due to viscoelastic relaxation following eruptions is important, as the generated signals can resemble renewed magma inflow. We study post-eruptive unrest at the subglacial Bárðarbunga volcano, Iceland, after a caldera collapse and major magma drainage in 2014–2015. Elevated seismicity began about 6 months after the eruption ended, including nine Mlw > 4.5 earthquakes. Global Navigation Satellite System and Sentinel-1 Interferometric Synthetic Aperture Radar geodesy are applied to evaluate post-eruptive ground deformation from 2015 to 2018. Horizontal velocities locally exceed 10 cm/year and rapidly decay with distance away from the caldera. We explore two end-member models and their combination to explain the post-eruptive deformation field: 1) viscoelastic relaxation caused by the co-eruptive caldera collapse and magma withdrawal, and 2) renewed magma inflow. We find parameter combinations for each model that explain the observed ground deformation. The purely viscoelastic relaxation model, consisting of a half-space composed of a 7-km thick elastic layer on top of a viscoelastic layer with a viscosity of 3.0 × 1018 Pa s reproduces broadly the observations. A simple magma inflow model consisting of a single point source with an inflow rate of 1 × 107 m3/year at 0.7 km depth broadly fits the observations, but may be unrealistic. A more elaborate model of magma inflow into a 10-km deep sill combined with slip on the caldera ring fault explains the observations well. Our results suggest that the co-eruptive deformation field is likely influenced by viscoelastic relaxation, renewed magma inflow, or a combination of both processes.

AB - Improvement of our understanding of the role of ground deformation due to viscoelastic relaxation following eruptions is important, as the generated signals can resemble renewed magma inflow. We study post-eruptive unrest at the subglacial Bárðarbunga volcano, Iceland, after a caldera collapse and major magma drainage in 2014–2015. Elevated seismicity began about 6 months after the eruption ended, including nine Mlw > 4.5 earthquakes. Global Navigation Satellite System and Sentinel-1 Interferometric Synthetic Aperture Radar geodesy are applied to evaluate post-eruptive ground deformation from 2015 to 2018. Horizontal velocities locally exceed 10 cm/year and rapidly decay with distance away from the caldera. We explore two end-member models and their combination to explain the post-eruptive deformation field: 1) viscoelastic relaxation caused by the co-eruptive caldera collapse and magma withdrawal, and 2) renewed magma inflow. We find parameter combinations for each model that explain the observed ground deformation. The purely viscoelastic relaxation model, consisting of a half-space composed of a 7-km thick elastic layer on top of a viscoelastic layer with a viscosity of 3.0 × 1018 Pa s reproduces broadly the observations. A simple magma inflow model consisting of a single point source with an inflow rate of 1 × 107 m3/year at 0.7 km depth broadly fits the observations, but may be unrealistic. A more elaborate model of magma inflow into a 10-km deep sill combined with slip on the caldera ring fault explains the observations well. Our results suggest that the co-eruptive deformation field is likely influenced by viscoelastic relaxation, renewed magma inflow, or a combination of both processes.

KW - Bárðarbunga

KW - GNSS

KW - InSAR

KW - viscoelasticity

KW - volcanic unrest

UR - https://www.scopus.com/pages/publications/85104028566

U2 - 10.1029/2020JB020157

DO - 10.1029/2020JB020157

M3 - Article

SN - 2169-9313

VL - 126

JO - Journal of Geophysical Research: Solid Earth

JF - Journal of Geophysical Research: Solid Earth

IS - 3

M1 - e2020JB020157

ER -

Ground Deformation After a Caldera Collapse: Contributions of Magma Inflow and Viscoelastic Response to the 2015–2018 Deformation Field Around Bárðarbunga, Iceland

Abstract

Bibliographical note

Other keywords

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