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| Titel |
The 2009 and 2010 eruptions and shallow intrusions at Piton de la Fournaise, La Réunion Island, seen by cGPS measurements |
| VerfasserIn |
Thomas Staudacher, Aline Peltier, Patrice Boissier, Andrea Di Muro |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250039289
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| Zusammenfassung |
| The Piton de la Fournaise volcano at La Réunion Island in the western Indian Ocean is one of
the most active volcanoes in the world. Its average eruption rate over the last 2 centuries is
one eruption every 9 months. Between 1998 and 2010 thirty eruptions occurred and produced
some 300Ã106 m3 of lava flows. Since the 2007 collapse of 340 m of the Dolomieu
caldera, the eruptive activity of the volcano changed with mainly the occurrence of
numerous shallow intrusions preceding days or weeks small summit eruptions. In
2009-2010, Piton de la Fournaise erupted successively in November 5, December 14,
2009 and in January 2, 2010. The one day lasting November and December 2009
eruptions started from en echelon fissures close to the summit around its eastern and
southern rims, respectively, whereas the January 2010 eruptive fissure opened on
the western flank inside of the Dolomieu crater. These three eruptions produced
less than 106 m3 of lava, but generated large ground deformation, of up to 70 cm,
recorded by the cGPS network of the volcano observatory and by cinematic GPS
measurements.
The long term survey showed a small extent of the ground deformation field and the small
ratios of base/summit displacements and vertical/horizontal displacements reveal the
involvement of shallow dykes to fed these successive eruptions. The cGPS network allowed
us to follow up precisely the pre eruptive ground deformations, the 40 to 90 minutes dyke
propagation toward the surface, as well as the ground deformations after the vent opening.
For the November and December 2009 eruptions, the dyke started below the western part of
the Dolomieu crater, before propagating to the east and the south, respectively. For the
January eruption, the dyke propagated along a more or less vertical pathway directly
to the western part of the Dolomieu crater. The two previous dyke injections of
November and December had increased the horizontal compressive stress of the
eastern side of the Dolomieu crater and did not favoured a new propagation to the
east. |
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