Publications

Dille, A.,  Nobile, A.,  Monsieurs, E.,  d'Oreye, N.,  Derauw, D.,  Malet, J-P.,  Kervyn, F.,  Kervyn, M. & Dewitte, O. 2017. ‘A multi-sensor approach to characterise the spatio-temporal dynamics of landslides in tropical urban environment: focus on Bukavu (DR Congo)’. Disaster and Resilience in the 21st Century. Book of abstracts. Brussels : Royal Academy for Overseas Sciences.

Résumé de colloque

Landslides represent one of the main hazards in dissected landscape, resulting every year in fatalities, structural and functional damage to infrastructures and serious disruptions of the organisation of societies. Loss of lives associated with landslides has been shown to be concentrated in developing countries, particularly in tropical areas where a combination of active tectonics, steep topography, intense rainfall and high population density is found. In most tropical regions, however, landslide process characterisation relevant for hazard assessment and urban planning remains rare. In the framework of a PhD research, we aim to increase our understanding of the ground deformation processes in the urban and peri-urban environments of the rapidly expanding city of Bukavu (DR Congo), located on the southern shore of Lake Kivu in the western branch of the East African Rift. The combined presence of natural triggers (heavy rainfall, tectonic activity…) and predisposing factors (steep topography…) make this city very prone to landsliding; slope instabilities being there responsible for a continuous degradation and destruction of houses, buildings and roads, but also of the water networks and sewerage infrastructures in several districts of the town. To characterise the ground deformations, a combination of remote sensing (space-borne Synthetic Aperture Radar (SAR) and Very High-Resolution optical sensors) and field-based (targeted UAV acquisitions, ground-based time-lapse stereo-photogrammetry and LiDAR, as well as repeated DGPS measurements) data and techniques adapted to the deformation dynamics, landslide characteristics (exposure condition and size) and the land cover context are being applied. A first field work and preliminary InSAR measures already allow us to detect various deformations patterns and landslide processes. It is expected that such multi-sensor, multi-scale and multi-temporal study will provide information that will help us to distinguish the signatures and trends of distinct landslide parameters and hence to precisely characterise the mechanism at play. The construction of displacement time series will be of great value for the understanding of the effect of environmental drivers (climate, seismicity, ect.) on the landslide dynamics. These outputs will also contribute to the update of the landslide inventory that serves as a basis for the assessment of the landslide susceptibility, hazard, and risk over the city of Bukavu.