Aso94: Aso seismic observation with broadband instruments

Kawakatsu, Hitoshi; Kaneshima, Satoshi; Matsubayashi, Hirotoshi; Ohminato, Takao; Sudo, Yasuaki; Tsutsui, Tomoki; Uhira, K.; Yamasato, Hitoshi; Ito, Hisao; Legrand, D.

doi:10.1016/s0377-0273(00)00166-9

Cited by 155 publications

(160 citation statements)

References 47 publications

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“…Kawakatsu et al (2000) call this semblance 'waveform semblance' and use it to locate the source region of the long-period tremor in a similar manner to that of Furumoto et al (1990Furumoto et al ( , 1992 (Fig. 10).…”

Section: Semblance Methods For Source Locationmentioning

confidence: 99%

Nature, wavefield properties and source mechanism of volcanic tremor: a review

Konstantinou

Schlindwein

2003

Journal of Volcanology and Geothermal Research

184

129

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Volcanic tremor has attracted considerable attention by seismologists because of its potential value as a tool for forecasting eruptions and better understanding the physical processes that occur inside active volcanoes. However, unlike tectonic earthquakes where the dominant source process is brittle failure of rock, the driving mechanism of tremor seems to involve complex interactions of magmatic fluids with the surrounding bedrock. These interactions are responsible for the following distinct characteristics found in volcanic tremor recorded at many volcanoes worldwide: (a) the onset of tremor may be emergent or impulsive, with its amplitude showing in many cases a direct relationship to the volcanic activity; (b) in the frequency domain the spectra consist of a series of sharp peaks in the band 0.1^7 Hz, representing either a fundamental frequency and its harmonics, or a random distribution, while quite often they exhibit temporal variations in their content; (c) the depth of the source can vary considerably from one volcano to another in the range of a few hundred metres to 40 km; (d) tremor may occur prior to and/or after eruptions with a duration that ranges from several minutes to several days or months. The methods used to study tremor include spectral analysis using both the Fast Fourier Transform and the Maximum Entropy Method, polarisation analysis of the wavefield and methods that make use of array data to deduce the backazimuth and type of the seismic waves as well as the location of the source. Visual and/or recorded acoustic observations of the ongoing volcanic activity have assisted in many cases to further constrain proposed physical mechanisms for the generation of tremor. The models suggested as possible sources of tremor can be grouped as follows: (a) fluid-flow-induced oscillations of conduits transporting magmatic fluids; (b) excitation and resonance of fluid-filled cracks; (c) bubble growth or collapse due to hydrothermal boiling of groundwater; (d) a variety of models involving the oscillations of magma bodies with different geometries. It has been proposed by many authors that the source of tremor is not unique and may differ from one volcano to another, a fact that adds more difficulty in the source modelling efforts. As data quality, computer power and speed are improving, it may be possible in the near future to decipher and accurately model tremor source processes at different volcanic environments. ß 2002 Elsevier Science B.V. All rights reserved.

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Section: Semblance Methods For Source Locationmentioning

confidence: 99%

Nature, wavefield properties and source mechanism of volcanic tremor: a review

Konstantinou

Schlindwein

2003

Journal of Volcanology and Geothermal Research

184

129

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“…However, dense networks of broadband receivers with station separation representing a fraction of the wavelength of VLP energy allow measurements of the coherence of VLP signals, and a derivation of source locations. To locate the VLP sources we use the semblance method [Neidell and Taner, 1971] extended to account for rectilinearity by Kawakatsu et al [2000]. Now called Radial Semblance (RS), this technique is well suited to calculating the source location of VLP signals.…”

Section: Introductionmentioning

confidence: 99%

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

Dawson

Whilldin²,

Chouet

2004

Geophysical Research Letters

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[1] Radial Semblance is applied to broadband seismic network data to provide source locations of Very-LongPeriod (VLP) seismic energy in near real time. With an efficient algorithm and adequate network coverage, accurate source locations of VLP energy are derived to quickly locate the shallow magmatic conduit system at Kilauea Volcano, Hawaii. During a restart in magma flow following a brief pause in the current eruption, the shallow magmatic conduit is pressurized, resulting in elastic radiation from various parts of the conduit system. A steeply dipping distribution of VLP hypocenters outlines a region extending from sea level to about 550 m elevation below and just east of the Halemaumau Pit Crater. The distinct hypocenters suggest the shallow plumbing system beneath Halemaumau consists of a complex plexus of sills and dikes. An unconstrained location for a section of the conduit is also observed beneath the region between Kilauea Caldera and Kilauea Iki Crater.

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“…Waveform inversions solving for the sourcetime histories of the moment-tensor and singleforce components of the source have become the primary tool to identify and understand the source mechanisms generating VLP signals recorded by broadband seismometers Kaneshima et al 1996;Ohminato et al 1998;Kawakatsu et al 2000;Nishimura et al 2000;Legrand et al 2000;Kumagai et al 2001Kumagai et al , 2003Chouet et al 2003Chouet et al , 2005Ohminato et al 2006;Ohminato 2006). When the wavelengths of observed seismic waves are much longer than the spatial extent of the source, the source may be approximated by a point source and the force system represented by the moment tensor and single force components is localized at this point.…”

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confidence: 99%

Shallow-conduit dynamics at Stromboli Volcano, Italy, imaged from waveform inversions

Chouet

Dawson

Martini

2008

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Modelling of Very-Long-Period (VLP) seismic data recorded during explosive activity at Stromboli in 1997 provides an image of the uppermost 1 km of its volcanic plumbing system. Two distinct dyke-like conduit structures are identified, each representative of explosive eruptions from two different vents located near the northern and southern perimeters of the summit crater. Observed volumetric changes in the dykes are viewed as the result of a piston-like action of the magma associated with the disruption of a gas slug transiting through discontinuities in the dyke apertures. Accompanying these volumetric source components are single vertical forces resulting from an exchange of linear momentum between the source and the Earth. In the dyke system underlying the northern vent, a primary disruption site is observed at an elevation near 440 m where a bifurcation in the conduit occurs. At a depth of 80 m below sea level, a sharp corner in the conduit marks another location where the elastic response of the solid to the action of the upper source induces pressure and momentum changes in the magma. In the conduit underlying the southern vent, the junction of two inclined dykes with a sub-vertical dyke at 520 m elevation is a primary site of gas slug disruption, and another conduit corner 280 m below sea level represents a coupling location between the elastic response of the solid and fluid motion.

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Aso94: Aso seismic observation with broadband instruments

Cited by 155 publications

References 47 publications

Nature, wavefield properties and source mechanism of volcanic tremor: a review

Nature, wavefield properties and source mechanism of volcanic tremor: a review

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

Shallow-conduit dynamics at Stromboli Volcano, Italy, imaged from waveform inversions

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