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Combining relative and absolute gravity measurements to enhance volcano monitoring
Author(s)
Language
English
Obiettivo Specifico
2.6. TTC - Laboratorio di gravimetria, magnetismo ed elettromagnetismo in aree attive
Status
Published
JCR Journal
JCR Journal
Peer review journal
Yes
Title of the book
Issue/vol(year)
7/74(2012)
ISSN
0258-8900
Electronic ISSN
1432-0819
Publisher
Springer Berlin Heidelberg
Pages (printed)
1745-1756
Issued date
June 16, 2012
Keywords
Abstract
To achieve a balance between uncertainty and
efficiency in gravity measurements, we have investigated the applicability of combined measurements of absolute and
relative gravity as a hybrid method for volcano monitoring.
Between 2007 and 2009, three hybrid gravity surveys were
conducted at Mt Etna volcano, in June 2007, July 2008, and
July 2009. Absolute gravity data were collected with two
absolute gravimeters, which represent the state of the art in
recent advances in ballistic gravimeter technology: (1) the
commercial instrument FG5#238 and (2) the prototype instrument
IMGC-02. We carried out several field surveys and
confirmed that both the absolute gravimeters can still
achieve a 10 μGal or better uncertainty even when they
are operated in severe environmental conditions. The use
of absolute gravimeters in a field survey of the summit area
of Mt Etna is unprecedented. The annual changes of the
gravity measured over 2007–2008 and 2008–2009 provide
unequivocal evidence that during the 2007–2009 period,
two main phenomena of subsurface mass redistribution occurred
in distinct sectors of the volcano, accompanying
different eruptive episodes. From 2007 to 2008, a gravity
change of −60 μGal was concentrated around the North-
East Rift. This coincided with a zone affected by strong
extensional tectonics, and hence might have been related
to the opening of new voids. Between 2008 and 2009, a
North-South elongate feature with a maximum gravity
change of +80 μGal was identified in the summit craters
area. This is interpreted to indicate recharge of a deepintermediate
magma storage zone, which could have occurred
when the 2008–2009 eruption was still ongoing.
efficiency in gravity measurements, we have investigated the applicability of combined measurements of absolute and
relative gravity as a hybrid method for volcano monitoring.
Between 2007 and 2009, three hybrid gravity surveys were
conducted at Mt Etna volcano, in June 2007, July 2008, and
July 2009. Absolute gravity data were collected with two
absolute gravimeters, which represent the state of the art in
recent advances in ballistic gravimeter technology: (1) the
commercial instrument FG5#238 and (2) the prototype instrument
IMGC-02. We carried out several field surveys and
confirmed that both the absolute gravimeters can still
achieve a 10 μGal or better uncertainty even when they
are operated in severe environmental conditions. The use
of absolute gravimeters in a field survey of the summit area
of Mt Etna is unprecedented. The annual changes of the
gravity measured over 2007–2008 and 2008–2009 provide
unequivocal evidence that during the 2007–2009 period,
two main phenomena of subsurface mass redistribution occurred
in distinct sectors of the volcano, accompanying
different eruptive episodes. From 2007 to 2008, a gravity
change of −60 μGal was concentrated around the North-
East Rift. This coincided with a zone affected by strong
extensional tectonics, and hence might have been related
to the opening of new voids. Between 2008 and 2009, a
North-South elongate feature with a maximum gravity
change of +80 μGal was identified in the summit craters
area. This is interpreted to indicate recharge of a deepintermediate
magma storage zone, which could have occurred
when the 2008–2009 eruption was still ongoing.
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article
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