Context and objectives
Nyiragongo and Nyamulagira volcanoes are amongst the most active in Africa. They are the sources of various hazards that threaten the region of Goma (N-Kivu, D.R. of Congo). The Nyiragongo eruption that occurred in January 2002 produced spectacular lava flows that destroyed about 10-15 % of the city of Goma and paralyzed ~80 % of the regional economy. Although the amount of casualties was limited, hundred thousands of inhabitants were forced to evacuate in difficult chaotic conditions. The long term socio-economic impact of the eruption is likely the most important; it has added more pressure on populations in an unstable and sensitive area. The main objectives of this initiative are to provide these three interconnected end-users working in the Nyiragongo – Nyamulagira volcanic context with appropriate products and services to assess the volcanic hazards and to mitigate the related risks. It follows three parallel axes: strengthening of the local capacity with new products and services, transversal pluri-disciplinary approach and capacity building including implication and training of the end users. GORISK is acting upstream of the division between direct and indirect volcanic risks. The direct risks are essentially related to short-term volcanic crisis and erupted material, whereas indirect risk deals with mid- to long-term effects on the environment or/and the population.
Ground deformation: A ground based network of 5 tiltmeters has been deployed on the southern part of the volcano. Thanks to additional support obtained from NMNH and MAE of Luxembourg, a geodetic GPS network has also been deployed involving 7 stations including one in Rwanda as a result of extended transnational collaborations.
The deformations associated to Nyiragongo and Nyamulagira eruptions as detected by InSAR have been studied into detailed and subsequent models have been proposed (e.g. Nyiragongo 2002 eruption: Wauthier et al., submitted). These models are of the highest importance for the understanding of the geodynamic mechanisms and therefore the hazard assessment and risk mitigation in the area.
Geochemistry monitoring: A permanent station has been installed in a Mazuku in town. Continuous measurements of CO2 and Radon gas fluxes are performed; to assess for the link with the volcanic activity a long period of observation is required and the results are under process. Dozens of water samples have been collected in a wide area by the CEMUBAC health partner. The samples are coming from areas prone and areas free of volcanic plume. Preliminary results are showing a clear relation with the distribution of some elements like Chloride and Fluorine.
Map update: The map of Goma has been produced based on digitization of a Quickbird image acquired in 2008. A new volcanological map has also been produced based on a compilation of various sources of data including multispectral and multitemporal satellite data.
Sustainability of the developed tool:
Besides the training of two members of the GVO staff in GIS and remote sensing provided at RMCA in the frame of the annual sessions, training was also organized during the field campaign to ensure the maintenance of the provided services.