Analysis of seismic and acoustic observations at Arenal Volcano, Costa Rica, 1995–1997

Hagerty, M. T.; Schwartz, S. Y.; Garcés, Milton; Protti, Marino

doi:10.1016/s0377-0273(00)00162-1

Cited by 143 publications

(153 citation statements)

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“…The dominant wave types have been identi¢ed either as P waves (Ferrucci et al, 1990) or as Love/SH waves (Ereditato and Luongo, 1994;Wegler and Seidl, 1997) showing a complicated overlapping pattern. Similar observations have been reported for the tremor wave¢eld in other volcanoes, such as Arenal where the dominant wave type was identi¢ed as S waves by Benoit and McNutt (1997), whereas Hagerty et al (2000) reported a very complicated composition of the wave¢eld and were unable to identify any particular wave type.…”

Section: The Nature Of Volcanic Tremorsupporting

confidence: 82%

“…The vertical axis marks the beginning of every calculation window and dark shades indicate high energy, light shades low energy. Note how the spectral lines representing each harmonic shift as time elapses, keeping the same horizontal distance from each other; this phenomenon, which has been termed 'gliding', was also observed at Arenal volcano by Hagerty et al (2000) (from Schlindwein et al, 1995; z AGU, reproduced with permission of American Geophysical Union). more than it is possible with the FFT, the Maximum Entropy Method (MEM) (Burg, 1967) has been applied in a number of cases (PavlofMcNutt, 1986;Izu-Oshima-Yamaoka et al, 1991 ;Mt.…”

Section: The Nature Of Volcanic Tremormentioning

confidence: 78%

See 1 more Smart Citation

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: The Nature Of Volcanic Tremorsupporting

confidence: 82%

Section: The Nature Of Volcanic Tremormentioning

confidence: 78%

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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“…This is potentially important for seismo-acoustic studies of volcanic explosions, in which the differences in ratios of acoustic and seismic energies are explained as physical changes related to the source conditions (Hagerty et al 2000;Rowe et al 2000;Johnson et al 2003). Johnson & Aster (2005), Sciotto et al (2011) and Andronico et al (2013) have all noted that the computation of the seismic energy needs to take into account the site effects, which should improve the accuracy of the estimation of the volcanic acoustic seismic ratio (VASR).…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, it is frequently observed in the case of volcanic explosions that the air waves are coupled into the seismic record (e.g. Hagerty et al 2000;De Angelis et al 2012). More recently, Ichihara et al (2012) proposed a method based on the cross-correlation of seismic and acoustic signals, to identify the coupling.…”

Section: Introductionmentioning

confidence: 99%

Site effect determination using seismic noise from Tungurahua volcano (Ecuador): implications for seismo-acoustic analysis

Palacios

Kendall²,

Mader³

2015

Geophysical Journal International

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University of Bristol -Explore Bristol Research General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. S U M M A R YScattering and refractions that occur in the heterogenous near-surface beneath seismic stations can strongly affect the relative amplitudes recorded by three-component seismometers. Using data from Tungurahua volcano we have developed a procedure to correct these 'site effects'. We show that seismic noise signals store site information, and then use their normalized spectral amplitudes as site frequency response functions. The process does not require a reference station (as per the S-wave and coda methods) or assume that the vertical amplitude is constant (the H/V component ratio method). Correcting the site effects has three consequences on data analysis: (1) improvement of the seismic source location and its energy estimation; (2) identification of a strong influence on the volcanic acoustic seismic ratio (VASR) and (3) decoupling the air wave impact on the ground caused by explosions or eruption jets. We show how site effect corrections improve the analysis of an eruption jet on 2006 July 14-15, appearing two periods of strong acoustic energy release and a progressive increase of the seismic energy, reaching the maximum before finishing the eruption.

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“…Buckingham and Garcs [1996] presented a model in which sound is generated as a wave transmitted to the air from an explosive source embedded within the magma column, and its waveform is due to the resonance of the magma column. Since then, these models have been respectively applied to other Strombolian eruptions on different volcanoes [e.g., Johnson et al, 2004;Vergniolle et al, 2004;Hagerty et al, 2000].…”

Section: Introductionmentioning

confidence: 99%

Airwaves generated by an underwater explosion: Implications for volcanic infrasound

et al. 2009

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[1] A shallow explosion in a fluid is one of the fundamental processes of airwave generation in volcanic eruptions. To better understand the mechanism of the airwave generation, underwater explosion experiments were conducted. Although the underwater explosions have been intensely studied over the last century, airwaves have received little attention. In this study, pressure waves were measured in air and under water, and the corresponding motion of the water surface was captured by a high-speed video camera. Airwaves and associated styles of the surface motion show similarities determined by the scaled depth, defined as the depth divided by the cubic root of the explosion energy. The air waveforms are quite different from the pressure waves measured in the water and cannot be completely explained by linear transmission of pressure waves from water to air. The mechanism of airwave generation is a combination of wave transmission and dynamics of the interface boundary. The first mechanism directly reflects the explosion source, and the same source is also observed as the underwater pressure waves. On the other hand, the second is not necessarily visible in the underwater pressure waves but will provide information on the mechanical properties and behavior of the material above the explosion source. Each mechanism is analyzed in the experiments.

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Analysis of seismic and acoustic observations at Arenal Volcano, Costa Rica, 1995–1997

Cited by 143 publications

References 38 publications

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

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

Site effect determination using seismic noise from Tungurahua volcano (Ecuador): implications for seismo-acoustic analysis

Airwaves generated by an underwater explosion: Implications for volcanic infrasound

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