Application of near real‐time radial semblance to locate the shallow magmatic conduit at Kilauea Volcano, Hawaii

Dawson, Phillip B.; Whilldin, D.; Chouet, Bernard

doi:10.1029/2004gl021163

Cited by 41 publications

(22 citation statements)

References 10 publications

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“…First, magma storage regions can consist of an interconnected series of sills (e.g. Hildreth 1981; Dawson et al 2004;Sánchez et al 2004). These sills may exploit either modal pre-existing fault orientation.…”

Section: Elliptical Calderas In the Kenyan Riftmentioning

confidence: 99%

Influence of regional tectonics and pre-existing structures on the formation of elliptical calderas in the Kenyan Rift

Robertson

Biggs

Cashman

et al. 2015

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Calderas are formed by the collapse of large magma reservoirs and are commonly elliptical in map view. The orientation of elliptical calderas is often used as an indicator of the local stress regime; but, in some rift settings, pre-existing structural trends may also influence the orientation. We investigated whether either of these two mechanisms controls the orientation of calderas in the Kenyan Rift. Satellite-based mapping was used to identify the rift border faults, intra-rift faults and orientation of the calderas to measure the stress orientations and pre-existing structural trends and to determine the extensional regime at each volcano. We found that extension in northern Kenya is orthogonal, whereas that in southern Kenya is oblique. Elliptical calderas in northern Kenya are orientated NW-SE, aligned with pre-existing structures and perpendicular to recent rift faults. In southern Kenya, the calderas are aligned NE-SW and lie oblique to recent rift faults, but are aligned with pre-existing structures. We conclude that, in oblique continental rifts, pre-existing structures control the development of elongated magma reservoirs. Our results highlight the structural control of magmatism at different crustal levels, where pre-existing structures control the storage and orientation of deeper magma reservoirs and the local stress regime controls intra-rift faulting and shallow magmatism.

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Section: Elliptical Calderas In the Kenyan Riftmentioning

confidence: 99%

Influence of regional tectonics and pre-existing structures on the formation of elliptical calderas in the Kenyan Rift

Robertson

Biggs

Cashman

et al. 2015

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“…[6] The seismic energy release from the shallow region under the eastern edge of Halemaumau also has distinct characteristics: first as a source region of long-period (LP) seismicity [Almendros et al, 2001;Saccorotti et al, 2001;Almendros et al, 2002b;Battaglia et al, 2003;Kumagai et al, 2005]; and second as a recurring locus of very long period (VLP) signals [Chouet and Dawson, 1997;Ohminato et al, 1998;Almendros et al, 2002a;Dawson et al, 2004]. LP seismicity related to an active hydrothermal system was located in this region by Almendros et al [2001].…”

Section: Introductionmentioning

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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“…Instead, the results from various approaches have revealed intricate systems of dikes, sills, and small chambers with irregular shapes that extend upward through the crust (Preston, 2001;Dawson et al, 2004;Marsh, 2004;Thomson, 2004;Cartwright and Hansen, 2006;Zellmer and Annen, 2008;Paulatto et al, 2010). The geometries of these bodies will clearly control the degree of hydraulic continuity and connectivity, and they somewhat hamper simple magma migration through the entire plumbing system.…”

Section: Introductionmentioning

confidence: 99%

Geochemical evidence for mixing between fluids exsolved at different depths in the magmatic system of Mt Etna (Italy)

Paonita

Caracausi

Iacono-Marziano

et al. 2012

Geochimica et Cosmochimica Acta

112

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Application of near real‐time radial semblance to locate the shallow magmatic conduit at Kilauea Volcano, Hawaii

Cited by 41 publications

References 10 publications

Influence of regional tectonics and pre-existing structures on the formation of elliptical calderas in the Kenyan Rift

Influence of regional tectonics and pre-existing structures on the formation of elliptical calderas in the Kenyan Rift

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

Geochemical evidence for mixing between fluids exsolved at different depths in the magmatic system of Mt Etna (Italy)

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