Publication Date:
2017-04-04
Description:
Stromboli is well known for its persistent, normal explosive activity, consisting of intermittent, mild to
moderate, Strombolian explosions that typically occur every 10–20 min. All tephras erupted during this
activity usually fall back into the crater terrace, and consist of volatile-poor scoriae fed by Highly Porphyritic
(HP) magma. More occasionally, large explosions or “paroxysms” eject a greater quantity of tephra, mainly
consisting of HP scoriae and pumice clasts of Low Porphyritic (LP) magma, but also including large lithic
blocks. In addition to this activity, between 2004 and 2006 high energy explosions, displaying an
intermediate eruptive style between that of normal and paroxysmal explosions in terms of column height,
duration and tephra dispersal, were observed to occur at a frequency of one to eight events per year. While
many volcanological, geochemical and geophysical studies have focused in the last few years on the two endmembers
of activity, i.e. normal or paroxysmal, a detailed investigation on these intermediate types of events
has not been carried out yet. Here we report of a study on the 9 January 2005 explosion, one of the high
energy explosions during which the main fountaining phase lasted nearly a minute causing ejection of coarse
bombs up to a height of 120 m, and of ash and lapilli to N200 m. An accompanying ash plume rose up to
500 m at the end of the explosion. We present a multidisciplinary approach that integrates the results from
analysis of live-camera images with compositional and textural characterization of the erupted products.
Major element composition of glassy groundmass and 3D views of textures in the erupted scoriae support
the hypothesis based on volcanological observations that this explosion falls between normal and
paroxysmal activity, for which we use the term “intermediate”. By comparing the video-camera images of
the 9 January 2005 explosion with volcanological features of other high energy explosions that occurred at
Stromboli between June 2004 and October 2006, we find that three additional events can be considered
intermediate explosions, suggesting that this type of activity may be fairly common on this volcano. The
results of this study, although preliminary given our limited dataset, clearly indicate that the methodology
used here can be successfully applied to better define the range of eruptive styles typifying the normal
explosive activity, potentially improving our capability of eruption forecasting and assessing volcanic hazard
at Stromboli.
Description:
Published
Description:
541-550
Description:
1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
Description:
JCR Journal
Description:
open
Keywords:
Stromboli
;
volcano monitoring
;
05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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