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| Titel |
Seismic characterization of pyroclastic flow activity at Soufrière Hills Volcano, Montserrat, 8 January 2007 |
| VerfasserIn |
S. Angelis, V. Bass, V. Hards, G. Ryan |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 7, no. 4 ; Nr. 7, no. 4 (2007-07-23), S.467-472 |
| Datensatznummer |
250004656
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| Publikation (Nr.) |
 copernicus.org/nhess-7-467-2007.pdf |
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| Zusammenfassung |
| A partial dome collapse with concurrent pyroclastic flow (PF) activity
occurred at Soufrière Hills Volcano (SHV), Montserrat on 8 January 2007.
Pyroclastic density currents were observed to propagate from the Northwest
and West sectors of the summit dome into the heads of Tyres Ghaut and Gages
Valley, respectively. Between 10:00 and 10:15 UTC pyroclastic flows entered
Tyres Ghaut and from there descended into the Belham Valley reaching a
distance of about 5 km from the source. Pyroclastic flow activity on the
Northwest and West side of the edifice continued at high levels over the
following 1.5 h, although run-out distances of individual flows did not
exceed 1.5 km. Subsequent observations showed that material had been removed
from the lower Northwest side of the dome leaving an amphitheatre-like
structure cutting through the old crater rim. The seismic waves excited by
the propagation of pyroclastic flows were recorded by the Montserrat Volcano
Observatory's network of broadband seismometers. The seismic records show
the onset of a continuous signal before 09:30 UTC with gradually increasing
amplitudes and spectral energy in the 1–8 Hz band. The signal rapidly
increased in amplitude and a characteristic spindle-shaped waveform with
broadband energy (1–25 Hz) was observed accompanying large PF that descended
along the slopes of the volcano. The main phase was followed by a sequence
of individual seismic pulses which correlated well with visual observations
of PF. PF are a major hazard at SHV and pose significant risk for the
population living in the proximity of the volcano. They can occur with
little or no warning and have the potential to reach inhabited areas to the
Northwest. The study of the seismic activity associated with the generation
and propagation of pyroclastic flows can help to identify characteristic
precursory seismic sequences providing valuable information to improve the
understanding of the hazards posed by the SHV and to allow better warning to
be given to the authorities. |
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