The velocity structure of Mount Erebus, Antarctica, and its lava lake

Dibble, R. R.; O'Brien, B. H.; Rowe, C. A.

doi:10.1029/ar066p0001

Cited by 11 publications

(5 citation statements)

References 12 publications

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“…The Lagrangian multipliers λ p.h,v control the trade‐off between data misfit and regularizing constraints and were varied to select the smoothest and most damped velocity perturbation model that minimized the data misfit while yielding absolute P‐wave velocities that were not appreciably less than the minimum P‐wave velocities of near‐surface Erebus phonolitic magma as estimated by Dibble et al . []. In addition to exploring the regularization parameters, the stability of the inversion was examined by varying parameterization details, including the ray tracing parameters and inversion model grid spacing, and in tests using only subsets of the travel‐time data.…”

Section: Methodology and Datamentioning

confidence: 99%

“…We assessed the importance of the initial model on the final results by testing a range of initial 1‐D models that were consistent with a priori knowledge of the geology, previous geophysical investigations [ Dibble et al ., ; Dibble et al ., ], and the results of a 2‐D large‐scale model for Ross Island obtained during the Tomo Erebus [ Zandomeneghi et al ., ; Maraj , ].…”

Section: Methodology and Datamentioning

confidence: 99%

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Internal structure of Erebus volcano, Antarctica imaged by high‐resolution active‐source seismic tomography and coda interferometry

et al. 2013

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[1] Erebus volcano, Antarctica has hosted a persistent convecting phonolite lava lake for over 40 years. The lake produces small (VEI 0-1) Strombolian eruptions resulting from gas slugs rising through the upper conduit system. High-resolution (to scale lengths of several hundreds of meters) three-dimensional P-wave tomographic velocity images were obtained to a depth of approximately 600 m below the volcano surface. Data were collected using 91 seismographs deployed over an approximately 4 by 4 km area of the summit region. Seismic illumination was provided by 12 chemical shots emplaced in shallow snow and ice boreholes. P-wave direct arrival travel-time measurements were used to invert for strong velocity anomalies (with spatial variations in V p exceeding AE1 km/s) associated with the uppermost few km. Shallow anomalies correlate with fumarolic ice caves, a prominent radial chilled dike, and ring structures associated with the caldera rim. Conduit structures feeding the lava lake and other vents within the Inner Crater are evidently too small (e.g., less than many 10 s of meters) to be imaged under the resolution limits of this experiment. However, combined velocity and coda interferometry scattering intensity images identify near-summit regions with both low velocity and high scattering that are candidates for magma accommodation. Results indicate a nonaxisymmetric near-summit magmatic system that is likely constrained by heterogeneous structures in the uppermost volcano. The most extensive volume of near-summit magma likely resides approximately 500 m NW of the active Inner Crater vents at depths of 500 m and more below the surface.Citation: Zandomeneghi D., R. Aster, P. Kyle, A. Barclay, J. Chaput, and H. Knox (2013), Internal structure of Erebus volcano, Antarctica imaged by high-resolution active-source seismic tomography and coda interferometry, J. Geophys.

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Section: Methodology and Datamentioning

confidence: 99%

Section: Methodology and Datamentioning

confidence: 99%

Internal structure of Erebus volcano, Antarctica imaged by high‐resolution active‐source seismic tomography and coda interferometry

et al. 2013

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“…We can, however, perform an order of magnitude predictive comparison between theory and observation in the 1–10 Hz frequency rage by applying a shallow vertical force (depth z =50 m) using the average time function shown in Figure a. In addition to the body wave source model of Haskell [] described in , we considered the seismic effects of applying this force to the surface of an elastic half‐space (Lamb's problem) to calculate the seismic response using reasonable bulk properties for the summit region of the volcano at the position of the lava lake [ Johnson , ; Dibble et al , , seismic velocities v p =2.2 km/s; v s =1.27 km/s; density ρ =2400 kg/m 3 ].…”

Section: Application Of the Bubble Expansion Modelmentioning

confidence: 99%

The first second of volcanic eruptions from the Erebus volcano lava lake, Antarctica—Energies, pressures, seismology, and infrasound

et al. 2013

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[1] We describe a multiparameter experiment at Erebus volcano, Antarctica, employing Doppler radar, video, acoustic, and seismic observations to estimate the detailed energy budget of large (up to 40 m-diameter) bubble bursts from a persistent phonolite lava lake. These explosions are readily studied from the crater rim at ranges of less than 500 m and present an ideal opportunity to constrain the dynamics and mechanism of magmatic bubble bursts that can drive Strombolian and Hawaiian eruptions. We estimate the energy budget of the first second of a typical Erebus explosion as a function of time and energy type. We constrain gas pressures and forces using an analytic model for the expansion of a gas bubble above a conduit that incorporates conduit geometry and magma and gas parameters. The model, consistent with video and radar observations, invokes a spherical bulging surface with a base diameter equal to that of the lava lake. The model has no ad hoc free parameters, and geometrical calculations predict zenith height, velocity, and acceleration during shell expansion. During explosions, the energy contained in hot overpressured gas bubbles is freed and partitioned into other energy types, where by far the greatest nonthermal energy component is the kinetic and gravitational potential energy of the accelerated magma shell (> 10 9 J). Seismic source energy created by explosions is estimated from radar measurements and is consistent with source energy determined from seismic observations. For the generation of the infrasonic signal, a dual mechanism incorporating a terminally disrupted slug is proposed, which clarifies previous models and provides good fits to observed infrasonic pressures. A new and straightforward method is presented for determining gas volumes from slug explosions at volcanoes from remote infrasound recordings.

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“… Dibble et al [1994] first noted the high degree of seismic waveform similarity for Strombolian eruptions of the Erebus lava lake, which are caused by large (up to 10‐m diameter) exsolved bubbles that explosively decompress near its surface [ Aster et al , 2003]. Because the lava lake rapidly refills, this eruptive scenario is especially conducive to producing nearly identical events.…”

Section: Reproducible Seismic Events At Mount Erebusmentioning

confidence: 99%

Monitoring rapid temporal change in a volcano with coda wave interferometry

Grêt

Snieder

Aster

et al. 2005

Geophysical Research Letters

109

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Multiply–scattered waves typically dominate the late part of the seismic coda in local earthquake seismograms. Small medium changes that have no detectable influence on the first arrivals are amplified by multiple scattering and may thus be readily observed in the coda. We exploit this idea using Coda Wave Interferometry to monitor temporal changes at Mount Erebus Volcano, Antarctica. Erebus is one of the few volcanoes on Earth with a long–lived convecting lava lake. Large exsolved gas bubbles generate impulsive Strombolian explosions that provide a repeating seismic source of seismic energy propagating through the strongly scattering geology of the volcano. We examined these signals during a particularly active eruptive two–month period between December, 1999 and February, 2000. Early seismograms are highly reproducible throughout this period. During the first month this is also the case for the coda. Approximately midway through this period, however, the seismic coda decorrelates rapidly over a period of several days. This indicates a rapid change in the scattering properties of the volcano, likely reflecting subtle changes in the near–summit magma/conduit system that would not be discernible using direct– or single–scattered seismic wave methods.

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The velocity structure of Mount Erebus, Antarctica, and its lava lake

Cited by 11 publications

References 12 publications

Internal structure of Erebus volcano, Antarctica imaged by high‐resolution active‐source seismic tomography and coda interferometry

Internal structure of Erebus volcano, Antarctica imaged by high‐resolution active‐source seismic tomography and coda interferometry

The first second of volcanic eruptions from the Erebus volcano lava lake, Antarctica—Energies, pressures, seismology, and infrasound

Monitoring rapid temporal change in a volcano with coda wave interferometry

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