The SAMAAV project: Study and Monitoring of Active African Volcanoes using ERS and ENVISAT data
F. Kervyn(1) , N. d'Oreye(2)
, and J. Fernandez(3)
Royal Museum for Central Africa,
(2) Natural History Museum of Luxembourg, 19, rue Josy Welter, L-7256 Walferdange, Luxembourg
(3) Instituto de Astronomia y Geodesia, CSIC, Ciudad Universitaria, 28040 Madrid, Spain
This paper is presenting the SAMAAV project that is
focusing on the observation and the analysis by InSAR of ground
deformation related to the volcanic activity of four major
African volcanoes. Compared to other places in the world, the
study and monitoring of the Ol Doinyo Lengai (Tanzania), the
Nyiragongo-Nyamuragira (DRC), the Mount Cameroon and the Fogo
(Cape Verde) is generally limited and often not present at all.
The project has started in September 2005 and some of the very
preliminary results are also presented. The main objectives are
1) the study of past eruptions using archived SAR data, 2) the
study of the deformations that can occur between these periods,
and 3) the monitoring of future deformations by the use of newly
acquired InSAR data. The project is supported by the ESA CAT-1 no.
3224. The leading idea behind this is of course the mitigation of
the volcanic risks incurred by populations, the environment, or
the air traffic.
Aseismic deformations can take place between the
eruptions as it has been recently unexpectedly observed on some
quiescent stratovolcanoes . It is now recognized that the
"life" of these edifices is not limited to the eruptive events or
their (short-term) precursory and post-eruptive activity. Magma
migration can take place in the upper mantle. As long as the
magma upwelling has not reached the brittle/ductile transition
zone, those internal changes can go unnoticed since the small
surface displacements are slow and are not accompanied by seismic
activity. The study of that inter-cycle activity is therefore
important in a volcano monitoring perspective. Deformations of
other origin such as ground water level variation, gravity driven
collapse or seasonal variations can also produce deformation
patterns in InSAR data   . Systematic monitoring should
help in discriminating them from the deformation signal. The
implementation of ground-based instrument networks is also
considered. Such networks can be deployed or densified in the
more relevant areas detected on InSAR deformation and coherence
maps. The InSAR measurements will be connected to ongoing
researches over the selected sites. They will therefore be
complemented by the use of ground-based techniques such as GPS,
tilt, seismic permanent network etc. The InSAR processing
facilities will also be developed on-site and will involve a
close collaboration with our local partners who are in charge of
the long term monitoring.
Royal Museum for Central Africa (Dr F. Kervyn)
Museum of Luxemburg (Dr N. d'Oreye)
Instituto de Astronomia y
Geodesia, CSIC (Dr J. Fernandez)
Dar es Salaam University.
Tanzania (Dr E. Mbede)
Dept of Geology - University of Ghent.
Belgium (Dr G. Ernst)
Dept. of Geology and Environmental Science,
University of Buea. Cameroon (Prof. S. Ayonghe)
of Tanzania, Dodoma. Tanzania (Prof. A. Mruma)
de Meteorologia e Geofisica de Cabo Verde (B. Faria)
Superior Tecnico, Lisbon. Portugal (Prof. J. Fonseca)
Magmas et Volcans. Blaise Pascal University, Clermont-Ferrand.
France. (Dr V. Cayol)
Laboratory for Engineering Geology.
University of Liege. Belgium. (Prof. E. Pirard)
Volcanological Observatory of Goma, Dem. Rep, Congo (Dr B. Bajope, Mr J. Durieux)
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