New Zealand Journal of Geology and Geophysics abstracts
A comparative study of low-frequency seismic signals recorded at
Stromboli volcano, Italy, and at Yasur volcano, Vanuatu
A. NABYL
J. DOREL
Observatoire de Physique du Globe
Centre de Recherches Volcanologiques
UMR 6524 CNRS/INSU
12 Avenue des landais
63000 Clermont-Ferrand, France
M. LARDY
Centre ORSTOM
BP 76 Port-Vila, Vanuatu
Abstract The explosive activities of the volcanoes Stromboli
(Aeolian Islands, Italy) and Yasur (Tanna Island, Vanuatu) produce
low-frequency seismic signals. Several types of such signals were identified
both on Stromboli (Types Is and IIs) and on Yasur (Types Iy, IIy, and
IIIy). The dominant frequencies of these signals fall generally between 1 and
3 Hz although sometimes frequencies in the range 3-6 Hz also exist.
The two volcanoes display similar seismic characteristics: the seismic signal
associated with the strombolian explosion is accompanied by a forerunner signal
that occurs several seconds before eruption and which corresponds to the time
separating the formation of the gas pocket at different levels in the magmatic
column and its reaching the surface.
The similar spectral characteristics of the volcanic background seismic noise
and the discrete signals suggest a common source.
Keywords seismology; volcanology; Yasur; volcanic
earthquakes; low-frequency seismic events; explosion earthquakes; Stromboli;
Italy; Vanuatu
New Zealand Journal of Geology and Geophysics, 1997, Vol. 40: 549-558
0028-8306/97/4004-0549 $7.00/0 (c) The Royal Society of New Zealand
1997
PDF file of entire paper: medium quality (1015K); (scanned from paper original: notes about this process)
This year's abstracts |
Journal home page |
All abstracts |
Publishing home page
