Open image in new windowLandslide Diversity in the Rwenzori Mountains (Uganda)
In the Rwenzori Mountains, at the border between Uganda and the D.R. Congo, landslides frequently occur and cause fatalities and substantial damage to agricultural land and infrastructure. Up until recently, no information on the landslide characteristics, occurrence or spatial distribution was available. The use of archive inventories and field surveys however allowed identifying the key mass wasting processes in this region and their triggering and controlling factors. Here, we present the results of these multi-temporal archive and field inventories. The Rwenzori mountains are diverse in lithology, topography and land use patterns. This diversity in landslide controlling factors is also reflected in the types of landslides that occur in this 3000 km2 large region. The majority of the Rwenzori Mountains consists of steep slopes on gneiss, mica-schists and amphibolite lithologies. A dominance of shallow translational soil slides is observed in gneiss while the amphibolite is found not to be prone to such landslides. This is in sharp contrast to the lowlands, which are characterized by gentle slopes and a rift alluvium lithology. In contrast to what was expected, the largest landslide densities are found in these lowlands where large, deep-seated rotational soil slides with head scarps up to 30 m depth prevail. In both the lowlands and the uplands, slope gradients appears to be the main topographic predictor for the spatial occurrence of landslides. Finally, concerning landslide triggering events, in both the archive inventory and the field surveys, rainfall-triggered landslides are the most common but co-seismic slides were also observed.
KeywordsLandslides Rwenzori Mountains East-African rift
This study was supported by the Belgium Science Policy (BELSPO) through the AfReSlide project BR/121/A2/AfReSlide entitled ‘Landslides in Equatorial Africa: Identifying culturally, technically and economically feasible resilience strategies’ and by the the Flemish Interuniversity Council for Development Cooperation (VLIR-UOS) in the framework of the South Initiative project “Identification and analysis of land degradation hot spots, their socio-economic and physical controls and implications in the Mt Rwenzori region”.
- Jacobs L, Dewitte O, Poesen J, Maes J, Mertens K, Sekajugo J, Kervyn M (2016b) Landslide characteristics and spatial distribution in the Rwenzori Mountains, Uganda. J Afr Earth Sci doi:10.1016/j.jafrearsci.2016.05.013
- Koehn D, Lindenfeld M, Rümpker G et al (2010) Active transsection faults in rift transfer zones: evidence for complex stress fields and implications for crustal fragmentation processes in the western branch of the East African Rift. Int J Earth Sci 99:1633–1642. doi:10.1007/s00531-010-0525-2 CrossRefGoogle Scholar
- Maes J, Kervyn M, de Hontheim A, Dewitte O, Jacobs L, Mertens K, Poesen J (2017) Landslide risk reduction measures: A review of practices and challenges for the tropics. Prog Phys Geogr, doi:10.1177/0309133316689344
- Ost L, Van Den Eeckhaut M, Poesen J, Vanmaercke-Gottigny MC, Ost Lieven (2003) Characteristics and spatial distribution of large landslides in the Flemish Ardennes (Belgium). Zeitschrift fur Geomorphol N F 47:329–350Google Scholar
- Simmons WC (1930) Local earth tremors recorded in February and March connected with an epicenter near Rwenzori. Geol. Surv. Dept. Uganda, Ann. Rep. for 1929: 33–37Google Scholar
- Statoids (2013) Administrative divisions of countries. http://www.statoids.com/uug.html. Accessed 15 April 2014
- UNESCO (1966) Earthquake Reconnaissance Mission, Uganda, The Toro earthquake of 20 March 1966. UNESCO. http://unesdoc.unesco.org/images/0000/000077/007799EB.pdf. Accessed 25 April 2014
- USGS (2014) Significant earthquake archive. Earthquake hazard program. http://earthquake.usgs.gov/earthquakes/eqinthenews/. Accessed 4th December 2014
- USGS (2015) Earthquake archives. http://earthquake.usgs.gov/earthquakes/search/. [on line] Accessed 31th July 2015