Stress field control of eruption dynamics at a rift volcano: Nyamuragira, D.R.Congo

Wadge, G.; Burt, Louise

doi:10.1016/j.jvolgeores.2011.06.012

Cited by 47 publications

(65 citation statements)

References 37 publications

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“…[71] The 1977 eruption appears to have induced a 2.4-fold increase in eruption rates at neighboring Nyamulagira volcano [Burt et al, 1994;Wadge and Burt, 2011], while the 2002 eruption may have decreased the lava output rate at Nyamulagira [Wadge and Burt, 2011]. Large dikes, such as the ones in this study, imply stress perturbations at a rift scale that could also affect the 15 km-distant Nyamulagira volcano and change its eruption rate or its intruded versus extruded magma volume.…”

Section: Comparisons With the 1977 Eruptionmentioning

confidence: 92%

Magma sources involved in the 2002 Nyiragongo eruption, as inferred from an InSAR analysis

Wauthier¹,

Cayol²,

Kervyn³

et al. 2012

J. Geophys. Res.

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along a 20 km-long fracture network extending from the volcano to the city of Goma. The event was captured by InSAR data from the ERS-2 and RADARSAT-1 satellites. A combination of 3D numerical modeling and inversions is used to analyze these displacements. Using Akaike Information Criteria, we determine that a model with two subvertical dikes is the most likely explanation for the 2002 InSAR deformation signal. A first, shallow dike, 2 km high, is associated with the eruptive fissure, and a second, deeper dike, 6 km high and 40 km long, lies about 3 km below the city of Goma. As the deep dike extends laterally for 20 km beneath the gas-rich Lake Kivu, the interaction of magma and dissolved gas should be considered as a significant hazard for future eruptions. A likely scenario for the eruption is that the magma supply to a deep reservoir started ten months before the eruption, as indicated by LP events and tremor. Stress analysis indicates that the deep dike could have triggered the injection of magma from the lake and shallow reservoir into the eruptive dike. The deep dike induced the opening of the southern part of this shallow dike, to which it transmitted magma though a narrow dike. This model is consistent with the geochemical analysis, the lava rheology and the pre-and post-eruptive seismicity. We infer low overpressures (1-10 MPa) for the dikes. These values are consistent with lithostatic crustal stresses close to the dikes and low magma pressure. As a consequence, the dike direction is probably not controlled by stresses but rather by a reduced tensile strength, inherited from previous rift intrusions. The lithostatic stresses indicate that magmatic activity is intense enough to relax tensional stresses associated with the rift extension.

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Section: Comparisons With the 1977 Eruptionmentioning

confidence: 92%

Magma sources involved in the 2002 Nyiragongo eruption, as inferred from an InSAR analysis

Wauthier¹,

Cayol²,

Kervyn³

et al. 2012

J. Geophys. Res.

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“…Eruptions are fed by dykes and fissures that occasionally cut the summit caldera (~2 km in diameter), and more often propagate down the flanks of the volcano (Wadge and Burt 2011). Eruption onsets are characterised by the ejection of lava fountains that may reach 200-300 m in height, and may involve one or more fissure vents.…”

Section: Figurementioning

confidence: 99%

“…Recent satellite-based studies on SO 2 emissions have suggested that the effusive activity is characterized by a strong "excess" of sulfur (Carn and Bluth 2003;Bluth and Carn 2008;Head et al 2011) clearly exceeding those derived from petrologic models (Wallace 2001;Sharma et al, 2004, Shinohara 2008 (Wadge and Burt 2011). In order to reconcile the measured SO 2 emissions of Nyamuragira with the amount of erupted lava, an initial S content of about 5000 ppm in the Nyamuragira magma is required, although the maximum S content found in the primitive melts is nearly 3700 ppm (Head et al 2011).…”

Section: Figurementioning

confidence: 99%

“…Ripepe et al 2005;Calvari et al 2010;Coppola et al 2012), Piton de la Fournaise (Coppola et al 2009;Gouhier and Coppola 2011) and Kilauea (Di Bartola et al 2008, Koeppen et al, 2013, its application in the analysis of Nyamuragira eruptions has addressed only a few, with only qualitative observations (e.g., Wright and Pilger 2008;Wadge and Burt 2011).…”

Section: Introductionmentioning

confidence: 99%

“…Notably, since 1980 the long-term magma output rate at Nyamuragira has increased significantly (from 0.47 m 3 s -1 to 1.13 m 3 s -1 ) and eruptions have been considered to follow the so-called "pressure-cooker" model (Wadge 1981) whereby the eruptions take place when the magma exerts an overpressure that exceeds the wall rocks' strength and the confining pressure (Burt et al 1994;Wadge and Burt 2011). Thus far, the volumetric fluxes and effusive trends have been only inferred qualitatively (Wadge and Burt 2011) due to limited and sporadic measurements of lava discharge rates within recent years (Smithsonian Institution, 2001 to present).…”

Section: Introductionmentioning

confidence: 99%

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Thermal regimes and effusive trends at Nyamuragira volcano (DRC) from MODIS infrared data

Coppola

Cigolini

2013

Bull Volcanol

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New lava lake at Nyamuragira volcano revealed by combined ASTER and OMI SO₂ measurements

Campion

2014

Geophysical Research Letters

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We report recent satellite measurements of the SO 2 emissions from the Virunga Volcanic Group (VVG), which comprises the very active Nyamuragira and Nyiragongo volcanoes. Combining high time resolution data from the UV-operating OMI (Ozone Monitoring Instrument) with high ground resolution data from the IR-operating ASTER (Advanced Spaceborne Thermal Emission and Reflection radiometer), we show that (1) the SO 2 emissions from the VVG have increased severalfold since the end of the last eruption of Nyamuragira. (2) Nyamuragira, which used to have very low intereruptive emissions of SO 2 before this eruption, is now contributing to 60 to 90% of the combined emissions measured by OMI. Considering the eruptive history of Nyamuragira, the evidence from previous research for the existence of a shallow magma chamber, and the detection of isolated thermal anomalies since April 2014, we conclude that a deep-seated lava lake has formed in the N pit of Nyamuragira's caldera.

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Stress field control of eruption dynamics at a rift volcano: Nyamuragira, D.R.Congo

Cited by 47 publications

References 37 publications

Magma sources involved in the 2002 Nyiragongo eruption, as inferred from an InSAR analysis

Magma sources involved in the 2002 Nyiragongo eruption, as inferred from an InSAR analysis

Thermal regimes and effusive trends at Nyamuragira volcano (DRC) from MODIS infrared data

New lava lake at Nyamuragira volcano revealed by combined ASTER and OMI SO₂ measurements

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Stress field control of eruption dynamics at a rift volcano: Nyamuragira, D.R.Congo

Cited by 47 publications

References 37 publications

Magma sources involved in the 2002 Nyiragongo eruption, as inferred from an InSAR analysis

Magma sources involved in the 2002 Nyiragongo eruption, as inferred from an InSAR analysis

Thermal regimes and effusive trends at Nyamuragira volcano (DRC) from MODIS infrared data

New lava lake at Nyamuragira volcano revealed by combined ASTER and OMI SO2 measurements

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New lava lake at Nyamuragira volcano revealed by combined ASTER and OMI SO₂ measurements