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)

(1) Royal Museum for Central Africa, 13, Leuvensestwg., 3080 Tervuren, Belgium
(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

Abstract

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 [1]. 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 [1] [2] [3]. 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.

2 PARTICIPANTS

Royal Museum for Central Africa (Dr F. Kervyn)

Natural History 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)

Geological Survey of Tanzania, Dodoma. Tanzania (Prof. A. Mruma)

Instituto Nacional de Meteorologia e Geofisica de Cabo Verde (B. Faria)

Instituto Superior Tecnico, Lisbon. Portugal (Prof. J. Fonseca)

Laboratoire 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)

3 REFERENCES

[1] Lu Z., Wicks C. Dzurisin D., Power J., Moran S., Thatcher W., Magmatic inflation at a dormant stratovolcano: 19961998 activity at Mount Peulik volcano, Alaska, revealed by satellite radar interferometry. Journal of Geophysical Research, Vol. 107, n. B7, 13 p, 2002.

[2] Fernandez J., Romero R., Carrasco D., Tiampo K. F., Rodridguez-Velasco G., Aparicio A., Arana V., Gonzalez-Matesanz F. J., Detection of displacements on Tenerife Island, Canaries, using radar interferometry. Geophysical Journal International, Vol. 160, 1, 33 - 45. 2005

[3] Lundgren P., Casu, F., Manzo, M., Pepe, A., Berardino, P. Sansosti, E., Lanari R., Gravity and magma induced spreading of Mount Etna volcano revealed by satellite radar interferometry, Geophys. Res. Lett., Vol. 31, 2004

 

 

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