Geological and Geomorphological Controls on Landslides: North Tanganyika-Kivu Rift Region, Tropical Africa

Abstract Landslides are geohydrological hazards that shape landscapes and may cause disasters. Despite their impact, the geological and geomorphological factors controlling their occurrence are not always well understood. This is especially so in mountainous areas in tropical regions where environmental conditions, such as bedrock type and soil weathering, may be specific. This research investigates these controls on landslides in the North Tanganyika-Kivu Rift region, tropical Africa. Our local-scale studies in the Ruzizi Gorge show how interactions between the rapid incision of the gorge, the bedrock type and associated weathering, as well as the geomorphic legacy of past landslides, have created a complex system in which landslide activity is episodic and scale-dependent, improving our understanding of the drivers of landslides in tropical river gorges. Our regional study demonstrates the importance of considering lithological complexity, the chronology of landslide occurrence and the long-term legacy of landscape evolution in understanding landslide characteristics in rift-prone tropical mountainous regions.