Pressure changes associated with the ascent and bursting of gas slugs in liquid-filled vertical and inclined conduits

James, Michael; Lane, S. J.; Chouet, Bernard; Gilbert, Jennifer

doi:10.1016/s0377-0273(03)00232-4

Cited by 130 publications

(109 citation statements)

References 38 publications

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“…In both simulations the 'void' bubble has an initial volume of ∼470 m 3 and pressure of ∼3.9 MPa. This represents a gas mass of between ∼3800 and 9400 kg for end-members of pure H 2 O or pure CO 2 that covers the possible range of major volatile species [Gerlach et al, 2002], assuming a temperature of ∼1400 K. Note that in this system, thermal effects and nonideal gas behavior are all secondary processes and can be neglected; the dynamics are controlled by liquid inertial and viscous forces [Clift et al, 1978;Seyfried and Freundt, 2000;James et al, 2004James et al, , 2008.…”

Section: Source Dynamicsmentioning

confidence: 99%

Seismic source mechanism of degassing bursts at Kilauea Volcano, Hawaii: Results from waveform inversion in the 10–50 s band

et al. 2010

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) summit eruptive activity at Kilauea Volcano is characterized by explosive degassing bursts accompanied by very long period (VLP) seismic signals. We model the source mechanisms of VLP signals in the 10-50 s band using data recorded for 15 bursts with a 10-station broadband network deployed in the summit caldera. To determine the source centroid location and source mechanism, we minimize the residual error between data and synthetics calculated by the finite difference method for a point source embedded in a homogeneous medium that takes topography into account. The VLP signals associated with the bursts originate in a source region ∼1 km below the eastern perimeter of Halemaumau pit crater. The observed waveforms are well explained by the combination of a volumetric component and a vertical single force component. For the volumetric component, several source geometries are obtained which equally explain the observed waveforms. These geometries include (1) a pipe dipping 64°t o the northeast; (2) two intersecting cracks including an east striking crack (dike) dipping 80°to the north, intersecting a north striking crack (another dike) dipping 65°to the east; (3) a pipe dipping 58°to the northeast, intersecting a crack dipping 48°to the westsouthwest; and (4) a pipe dipping 57°to the northeast, intersecting a pipe dipping 58°to the west-southwest. Using the dual-crack model as reference, the largest volume change obtained among the 15 bursts is ∼24,400 m 3 , and the maximum amplitude (peak to peak) of the force is ∼20 GN. Each burst is marked by a similar sequence of deflation and inflation, trailed by decaying oscillations of the volumetric source. The vertical force is initially upward, synchronous with source deflation, then downward, synchronous with source reinflation, followed by oscillations with polarity opposite to the volumetric oscillations. This combination of force and volume change is attributed to pressure and momentum changes induced during a fluid dynamic source mechanism involving the ascent, expansion, and burst of a large slug of gas within the upper ∼150 m of the magma conduit. As the slug expands upon approach to the surface and more liquid becomes wall supported by viscous shear forces, the pressure below the slug decreases, inducing conduit deflation and an upward force on the Earth. The final rapid slug expansion and burst stimulate VLP and LP oscillations of the conduit system, which slowly decay due to viscous dissipation and elastic radiation. Consideration of the fluid dynamic arguments leads us to prefer the dual-crack VLP source model as it is the only candidate model capable of producing plausible values of length scales and pressure changes. The magnitudes of the vertical forces observed in the 15 bursts appear consistent with slug masses of 10 4 to 10 6 kg.Citation: Chouet, B. A., P. B. Dawson, M. R. James, and S. J. Lane (2010), Seismic source mechanism of degassing bursts at Kilauea Volcano, Hawaii: Results from waveform inversion in the 10-50 s band,

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Section: Source Dynamicsmentioning

confidence: 99%

Seismic source mechanism of degassing bursts at Kilauea Volcano, Hawaii: Results from waveform inversion in the 10–50 s band

et al. 2010

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“…Vergniolle et al 1996;Chouet et al 2003Chouet et al , 2008Marchetti and Ripepe 2005), experimental studies (e.g. James et al 2004James et al , 2006James et al , 2008Lane et al 2013), and field observations (e.g. Chouet et al 1974;Blackburn et al 1976;Ripepe et al 1993Ripepe et al , 2005Patrick et al 2007;Harris et al 2012;Taddeucci et al 2012a, b;Gaudin et al 2014;Bombrun et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Recycled ejecta modulating Strombolian explosions

et al. 2016

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Two main end-members of eruptive regimes are identified from analyses of high-speed videos collected at Stromboli volcano (Italy), based on vent conditions: one where the vent is completely clogged by debris, and a second where the vent is open, without any cover. By detailing the vent processes for each regime, we provide the first account of how the presence of a cover affects eruptive dynamics compared to open-vent explosions. For clogged vents, explosion dynamics are controlled by the amount and grain size of the debris. Fine-grained covers are entirely removed by explosions, favouring the generation of fine ash plumes, while coarse-grained covers are only partially removed by the explosions, involving minor amounts of ash. In both fine-and coarse-grained cases, in-vent ground deformation of the debris reflect variations in the volumetric expansion of gas in the conduit, with rates of change of the deformation comparable to ground inflation related to pre-burst conduit pressurization. Eruptions involve the ejection of relatively slow and cold bombs and lapilli, and debris is observed to both fall back into the vent after each explosion and to gravitationally accumulate between explosions by rolling down the inner crater flanks to produce the cover itself. Part of this material may also contribute to the formation of a more degassed, crystallized and viscous magma layer at the top of the conduit. Conversely, open-vent explosions erupt with hotter pyroclasts, with higher exit velocity and with minor or no ash phase involved.

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“…The wavefield is generated by the excitation of only few degrees of freedom of the complex fluid-dynamical source system. Possible models of the production of these oscillations have been postulated by Julian (1994), Ida (1996) and James et al (2004). In particular, Julian (1994) suggested an organ pipe model, with a constant rate supply of fluids inside a cylinder conduit for a variety of almost periodic signals observed on volcanoes.…”

Section: Discussionmentioning

confidence: 99%

“…The same function for the generation of ground vibration (the coupling between degassing and the conduit) can be ruled by the variable geometry of the conduit (James et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

Characterization of Strombolian events by using independent component analysis

Ciaramella

Lauro

Martino

et al. 2004

Nonlin. Processes Geophys.

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Abstract. We apply Independent Component Analysis (ICA) to seismic signals recorded at Stromboli volcano. Firstly, we show how ICA works considering synthetic signals, which are generated by dynamical systems. We prove that Strombolian signals, both tremor and explosions, in the high frequency band (>0.5 Hz), are similar in time domain. This seems to give some insights to the organ pipe model generation for the source of these events. Moreover, we are able to recognize in the tremor signals a low frequency component (<0.5 Hz), with a well defined peak corresponding to 30 s.

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Pressure changes associated with the ascent and bursting of gas slugs in liquid-filled vertical and inclined conduits

Cited by 130 publications

References 38 publications

Seismic source mechanism of degassing bursts at Kilauea Volcano, Hawaii: Results from waveform inversion in the 10–50 s band

Seismic source mechanism of degassing bursts at Kilauea Volcano, Hawaii: Results from waveform inversion in the 10–50 s band

Recycled ejecta modulating Strombolian explosions

Characterization of Strombolian events by using independent component analysis

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