Publication Date:
2012-02-03
Description:
An edited version of this paper was published by AGU. Copyright (2010) American Geophysical Union
Description:
Seismic, deformation, and volcanic gas observations offer independent and complementary information
on the activity state and dynamics of quiescent and eruptive volcanoes and thus all contribute to volcanic
risk assessment. In spite of their wide use, there have been only a few efforts to systematically integrate and
compare the results of these different monitoring techniques. Here we combine seismic (volcanic tremor
and long‐period seismicity), deformation (GPS), and geochemical (volcanic gas plume CO2/SO2 ratios)
measurements in an attempt to interpret trends in the recent (2007–2008) activity of Etna volcano. We
show that each eruptive episode occurring at the Southeast Crater (SEC) was preceded by a cyclic phase
of increase‐decrease of plume CO2/SO2 ratios and by inflation of the volcano’s summit captured by the
GPS network. These observations are interpreted as reflecting the persistent supply of CO2‐rich gas bubbles
(and eventually more primitive magmas) to a shallow (depth of 1–2.8 km asl) magma storage zone
below the volcano’s central craters (CCs). Overpressuring of the resident magma stored in the upper
CCs’ conduit triggers further magma ascent and finally eruption at SEC, a process which we capture as
an abrupt increase in tremor amplitude, an upward (〉2800 m asl) and eastward migration of the source
location of seismic tremor, and a rapid contraction of the volcano’s summit. Resumption of volcanic activity
at SEC was also systematically anticipated by declining plume CO2/SO2 ratios, consistent with magma
degassing being diverted from the central conduit area (toward SEC).
Description:
Published
Description:
Q09008
Description:
1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
Description:
1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
Description:
1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
Description:
JCR Journal
Description:
reserved
Keywords:
volcano monitoring
;
Mt. Etna volcano
;
geochemistry and geophysics
;
volcanic tremor
;
04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
;
04. Solid Earth::04.08. Volcanology::04.08.01. Gases
;
04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
;
04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
