000007559 001__ 7559
000007559 005__ 20250310140139.0
000007559 0247_ $$2DOI$$a10.1029/2024JB029380
000007559 037__ $$aSCART-2025-0127
000007559 100__ $$aSoubestre, J.
000007559 245__ $$aDynamics of the 2021 Fagradalsfjall Eruption (Iceland) Revealed by Volcanic Tremor Patterns
000007559 260__ $$c2025
000007559 520__ $$aCo-eruptive volcanic tremor during the 2021 Fagradalsfjall eruption in Iceland (19 March–18 September 2021) is characterized using seismic and visual data recorded close to the eruption site and across the Reykjanes Peninsula. An automatic seismic network-based approach reveals several tremor patterns associated with seven phases of the eruption, including (a) continuous tremor located beneath the eruption site and attributed to pressure changes in the shallow vent system(s) in phases I, III, and VII, and (b) two patterns of minute- and hour-long intermittent tremor in May (phase II) and July–August (phases IV–VI), respectively. The first intermittent pattern of minute-long tremor bursts associated with pulsating lava fountains in May is attributed to magma degassing in a shallow reservoir (top 100 m) connected to a top-conduit. The progressive enlargement of both the top-conduit and shallow reservoir with time is estimated quantitatively using a collapsing foam model. Sudden changes of their geometries, as detected from tremor characteristics, are systematically associated with observed crater collapse events. The second intermittent pattern of cyclic hour-long tremor episodes associated with episodic effusive activity in July–August is attributed to magma flowing and cooling in the feeder dike connected to a sill at 5 km depth. The sill is fed by a constant influx of magma from the deeper plumbing system and stores magma during low discharge periods. The observed cyclicity of both the eruptive activity and the tremor is interpreted quantitatively with a sill-dike model accounting for magma cooling and induced cyclic viscosity changes in the dike.
000007559 536__ $$aIcelandic Research Fund, Rannis. Grant Number: 217738-051 & HORIZON 2020 EUROPE European Research Council. Grant Number: 787399-SEISMAZE/$$cIcelandic Research Fund, Rannis. Grant Number: 217738-051 & HORIZON 2020 EUROPE European Research Council. Grant Number: 787399-SEISMAZE/$$fIcelandic Research Fund, Rannis. Grant Number: 217738-051 & HORIZON 2020 EUROPE European Research Council. Grant Number: 787399-SEISMAZE
000007559 594__ $$aNO
000007559 6531_ $$avolcano seismology
000007559 6531_ $$aambient noise
000007559 6531_ $$atremor
000007559 6531_ $$aIceland
000007559 6531_ $$acovseisnet
000007559 700__ $$aCaudron, C.
000007559 700__ $$aMelnik, O.
000007559 700__ $$aLecocq, T.
000007559 700__ $$aJaupart, C.
000007559 700__ $$aShapiro, N.M.
000007559 700__ $$aJourneau, C.
000007559 700__ $$aÇubuk-Sabuncu, Y.
000007559 700__ $$aJónsdóttir, K.
000007559 773__ $$ne2024JB029380$$pJournal of Geophysical Research: Solid Earth$$v130$$y2025
000007559 8560_ $$fthomas.lecocq@ksb-orb.be
000007559 8564_ $$s1183423$$uhttp://publi2-as.oma.be/record/7559/files/jgrb57147-fig-0010-m.jpg$$yConceptual model of magma flow in the sill-dike system top-connected to the shallow-conduit system resulting in cyclic activity during phases IV–VI. (a) Four stages composing each cycle (described in the text). (b) Sketch of the sill-dike system, with observed shallow, intermediate, and deep tremor sources. (c) Example of 2-day long spectral width plot showing cycle #18 during phase VI, with the corresponding stages 1–4 according to subplot (a). (d)–(e) Drone images (from the Volcanology and Natural Hazards Research Group of the University of Iceland, Moreland et al. (2024)) taken above the crater at 14:24 UTC on 2 July (d) corresponding to stage 2 in subplots (a) and (c), and on the side of the crater at 21:47 UTC on 9 August (e) corresponding to stage 3 in subplots (a) and (c).
000007559 8564_ $$s21542$$uhttp://publi2-as.oma.be/record/7559/files/jgrb57147-fig-0010-m.jpg?subformat=icon-180$$xicon-180$$yConceptual model of magma flow in the sill-dike system top-connected to the shallow-conduit system resulting in cyclic activity during phases IV–VI. (a) Four stages composing each cycle (described in the text). (b) Sketch of the sill-dike system, with observed shallow, intermediate, and deep tremor sources. (c) Example of 2-day long spectral width plot showing cycle #18 during phase VI, with the corresponding stages 1–4 according to subplot (a). (d)–(e) Drone images (from the Volcanology and Natural Hazards Research Group of the University of Iceland, Moreland et al. (2024)) taken above the crater at 14:24 UTC on 2 July (d) corresponding to stage 2 in subplots (a) and (c), and on the side of the crater at 21:47 UTC on 9 August (e) corresponding to stage 3 in subplots (a) and (c).
000007559 8564_ $$s22797$$uhttp://publi2-as.oma.be/record/7559/files/jgrb57147-fig-0010-m.gif?subformat=icon$$xicon$$yConceptual model of magma flow in the sill-dike system top-connected to the shallow-conduit system resulting in cyclic activity during phases IV–VI. (a) Four stages composing each cycle (described in the text). (b) Sketch of the sill-dike system, with observed shallow, intermediate, and deep tremor sources. (c) Example of 2-day long spectral width plot showing cycle #18 during phase VI, with the corresponding stages 1–4 according to subplot (a). (d)–(e) Drone images (from the Volcanology and Natural Hazards Research Group of the University of Iceland, Moreland et al. (2024)) taken above the crater at 14:24 UTC on 2 July (d) corresponding to stage 2 in subplots (a) and (c), and on the side of the crater at 21:47 UTC on 9 August (e) corresponding to stage 3 in subplots (a) and (c).
000007559 905__ $$apublished in
000007559 980__ $$aREFERD