Volcanic tremor-source mechanisms and correlation with eruptive activity

Schick, R.

doi:10.1007/bf00126610

Cited by 36 publications

(11 citation statements)

References 21 publications

(27 reference statements)

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“…On occasions the activity increased, and sometimes a thick steam column and considerable explosive activity were observed. Schick (1988Schick ( , 1992 states that strong tremor is not necessarily accompanied by strong lava emission, but strong degassing of volcanoes does coincide with strong tremor. In the light of our observations on this Hekla eruption, it is also likely that the Hekla tremor rather reflects the vigour of the eruption than the amount of produced lava.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

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Volcanic tremor related to the 1991 eruption of the Hekla volcano, Iceland

Soosalu

Einarsson

Jakobsdóttir

2003

Bulletin of Volcanology

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Volcanic tremor at the Hekla volcano is directly related to eruptive activity. It starts simultaneously with the eruptions and dies down at the end of them. No tremor at Hekla has been observed during noneruptive times. The 1991 Hekla eruption began on 17 January, after a short warning time. Local seismograph stations recorded small premonitory earthquakes from 16:30 GMT on. At 17:02 GMT, low-frequency volcanic tremor became visible on the seismograph records, marking the onset of the eruption. The initial plinian phase of the eruption was short-lived. During the first day several fissures were active but, by the second day, the activity was already limited to a segment of one principal fissure. The eruption lasted almost 53 days. At the end of it, during the early hours of 11 March, volcanic tremor disappeared under the detection threshold and was followed by a swarm of small earthquakes. At the start of the eruption, the tremor amplitude rose rapidly and reached a maximum in only 10 min. The tremor was most vigorous during the first hour and started to decline sharply during the next hour, and later on more gently. During the eruption as a whole, the tremor had a continuous declining trend, with occasional increases lasting up to about 2 days. Spectral analysis of the tremor during the first 7 h of the eruption shows that it settled quickly, within a couple of minutes, to its characteristic frequency band, 0.5-1.5 Hz. The spectrum had typically one dominant peak at 0.7-0.9 Hz, and a few subdominant peaks. Hekla tremor likely has a shallow source. Particle motion plots suggest that it contains a significant component of surface waves. The tremor started first when the connection of the magma conduit with the atmosphere was reached, suggesting that degassing may contribute to its generation.

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Section: Conclusion and Discussionmentioning

confidence: 99%

“…This behaviour is not self-evident for every volcano. Some volcanoes show periods of volcanic tremor without observable eruptive activity (Schick 1988). At Etna, for example (e.g.…”

Section: Time History Of the Eruption In The Light Of Tremor Observatmentioning

confidence: 99%

Volcanic tremor related to the 1991 eruption of the Hekla volcano, Iceland

Soosalu

Einarsson

Jakobsdóttir

2003

Bulletin of Volcanology

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“…Many authors [see, e.g., Schick , 1988; Chouet and Shaw , 1991; Julian , 1994; Ida , 1996; Ripepe and Gordeev , 1999; Konstantinou and Schlindwein , 2002] have proposed models for the volcanic tremor. All have suggested that the fluid flow along the shallow part of the system is the origin of the steady state volcanic tremor.…”

Section: Modelingmentioning

confidence: 99%

Model for high‐frequency Strombolian tremor inferred by wavefield decomposition and reconstruction of asymptotic dynamics

et al. 2008

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[1] We study the volcanic tremor time series recorded by a broadband three-component seismic network installed at Stromboli volcano during 1997. By using decomposition methods in both frequency and time domains, we prove that Strombolian tremor can be described as a linear combination of nonlinear signals in time domain. These ''components'' are similar to those obtained for explosion quakes, with the only difference being the amplitude enhancement. We characterize each of these nonlinear signals both in terms of their wavefield properties as well as dynamic systems. Moreover, we take into account the complex processes of magma flow and turbulent degassing, looking at time and amplitude modulation of tremor on a suitable scale. The distribution of tremor amplitudes is Gaussian while the intertimes between the maxima in a suitable scale are described by a Poisson clustered process. Starting from these analyses, a first approximate model for volcanic tremor field can be deduced. The recorded signals, i.e., the elastic vibrations at a point, can be described by a nonlinear equation which gives limit cycles (different observed ''nonlinear modes''). This equation is governed by a time-dependent threshold which represents the variability of bubble flux. We take into account some inelasticity in the medium perturbing the elastic potential with a Gaussian function on a suitable scale. It acts as a radiance function modulating the frequency of the limit cycle. This proposed model is able to reproduce waveform, Fourier spectrum, and phase space dimension of one of the extracted nonlinear wave packets.

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“…This hypothesis is supported by a negative correlation between the gravity sequence recorded at PDN and the volcanic tremor observed at both PDN and ESP stations (placed respectively within a few meter from PDN gravity station and in the southeastern sector of the volcano). Given that volcanic tremor is generated by fluid flow as gases escape through open magma-filled conduits (SEIDL et al, 1981;SCHICK, 1988) and has an amplitude related to the intensity of turbulent motions (LEONARDI et al, 1999), it is likely that increased degassing in the inferred source leads to both a gravity (mass) decrease and an increase in the spectral amplitude of the volcanic tremor, giving rise to the observed negative correlation. Fig.…”

Section: Case Studiesmentioning

confidence: 99%

Review of Microgravity Observations at Mt. Etna: A Powerful Tool to Monitor and Study Active Volcanoes

Carbone

Greco

2007

Pure appl. geophys.

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Microgravity observations at Mt. Etna have been routinely performed as both discrete (since 1986) and continuous (since 1998) measurements. In addition to describing the methodology for acquiring and reducing gravity data from Mt. Etna, this paper provides a collection of case studies aimed at demonstrating the potential of microgravity to investigate the plumbing system of an active volcano and detect forerunners to paroxysmal volcanic events.

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Volcanic tremor-source mechanisms and correlation with eruptive activity

Cited by 36 publications

References 21 publications

Volcanic tremor related to the 1991 eruption of the Hekla volcano, Iceland

Volcanic tremor related to the 1991 eruption of the Hekla volcano, Iceland

Model for high‐frequency Strombolian tremor inferred by wavefield decomposition and reconstruction of asymptotic dynamics

Review of Microgravity Observations at Mt. Etna: A Powerful Tool to Monitor and Study Active Volcanoes

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