Publications

Wauthier, C.,  Smets, B.,  Hooper, A.,  Kervyn, F. & d'Oreye, N. 2017. ‘Steady-rate and long-term ground deformation associated with dry gas vents in the Lake Kivu area’. IAVCEI Scientific Assembly 2017. Book of abstracts.

Résumé de colloque

Dry gas vents correspond to an increasing lethal hazard to the local population in the Goma region in the Lake Kivu area (Democratic Republic of Congo). We processed a time series (« StaMPS » [Hooper, 2008]) of an ENVISAT ASAR dataset comprising 47 SAR scenes spanning 16 January 2003 to 25 March 2010, acquired along descending orbits. We identified new deforming areas on the northern shore of Lake Kivu, characterized by line of sight steady ground subsidence of ~15 mm/year. Two distinct areas can be identified : one centered on the Rumoka volcanic cone which was built during the 1912 eruption at Nyamulagira volcano, and another one, broader spatially and centered in the Bulengo area. Both areas include dry gas vents that are topographic depressions which release substantive amount of gases (mainly CO2 and CH4). The inversion of the StaMPS geodetic dataset led us to infer the presence of at least two deflating hydrothermal reservoirs accounting for the observed deformation. These findings provide crucial information about the deformation behavior and patterns associated with hazardous gas emanations areas in the populated Lake Kivu area and thus bear important implications for natural hazard assessment.