Publications

Smets, B.,  d'Oreye, N.,  Kervyn, M. & Kervyn, F. 2017. ‘The Nyiragongo lava lake (D.R. Congo): current state of knowledge and perspectives’. IAVCEI Scientific Assembly 2017. Book of abstracts.

Conference abstract

Nyiragongo volcano, in North Kivu, Democratic Republic of Congo, is among the most active volcanoes in Africa and on Earth. Since the first European observations in the late 19th Century, its eruptive activity mostly concentrated into its main crater, with the presence of a persistent lava lake from at least 1928 to 1977 and since 2002. The size, shape and elevation of this lava lake have evolved through time, modifying the topography of the main crater. In January 1977 and 2002, the uppermost magmatic system of Nyiragongo, including the lava lake, was drained during flank eruptions. Like any other persistent lava lake system, the Nyiragongo lava lake is a unique opportunity to directly monitor the dynamics of the upper magmatic system of the volcano. Monitoring the Nyiragongo lava lake also offers a chance to detect any change in the magmatic activity that could lead to a hazardous flank eruption. In this presentation, we focus on the dynamics of the Nyiragongo lava lake level and its relationship with the volcanic plumbing system, by describing the historical and most recent lava lake activity, and presenting new quantitative observations using close-range photogrammetry, a Stereographic Time-Lapse Camera (STLC) system and high-resolution satellite SAR and InSAR remote sensing. Results highlight that, contrary to some interpretations in the literature, the lava lake drainages appear to be the consequence and not the cause of the 1977 and 2002 flank eruptions. Two types of short-term lava lake level variations are observed. The first one corresponds to cyclic metre-scale variations attributed to gas piston activity. First STLC records in September 2011 show hour-scale gas piston cycles reaching up to 3.8 m, which are interpreted to be related to gas accumulation and release in the lava lake itself. The second type of variations corresponds to sporadic decametre-scale level rises or falls, which are related to major pressure changes in the upper magmatic system and may be responsible for topographic changes or ground deformation in the main crater. Finally, preliminary results of a large scientific expedition focused on the study of the Nyiragongo lava lake, which is planned in June 2017, will be presented, in order to highlight the perspective of new multidisciplinary studies on this remote persistent lava lake.