Exceptional Cluster of Simultaneous Shallow Landslides in Rwanda: Context, Triggering Factors, and Potential Warnings
Rwanda, in eastern tropical Africa, is a small, densely populated country where climatic disasters are often the cause of considerable damage and deaths. Landslides are among the most frequent hazards, linked to the country’s peculiar configuration including high relief with steep slopes, humid trop...
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MDPI AG
2024-09-01
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| author | Fils-Vainqueur Byiringiro Marc Jolivet Olivier Dauteuil Damien Arvor Christine Hitimana Niyotwambaza |
| author_facet | Fils-Vainqueur Byiringiro Marc Jolivet Olivier Dauteuil Damien Arvor Christine Hitimana Niyotwambaza |
| author_sort | Fils-Vainqueur Byiringiro |
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| description | Rwanda, in eastern tropical Africa, is a small, densely populated country where climatic disasters are often the cause of considerable damage and deaths. Landslides are among the most frequent hazards, linked to the country’s peculiar configuration including high relief with steep slopes, humid tropical climate with heavy rainfall, intense deforestation over the past 60 years, and extensive use of the soil for agriculture. The Karongi region, in the west-central part of the country, was affected by an exceptional cluster of more than 700 landslides during a single night (6–7 May 2018) over an area of 100 km<sup>2</sup>. We analyse the causes of this spectacular event based on field geological and geomorphology investigation and CHIRPS and ERA5-Land climate data. We demonstrate that (1) the notably steep slopes favoured soil instability; (2) the layered soil and especially the gravelly, porous C horizon allowed water storage and served as a detachment level for the landslides; (3) relatively low intensity, almost continuous rainfall over the previous two months lead to soil water-logging; and (4) acoustic waves from thunder or mechanical shaking by strong wind destabilized the water-logged soil through thixotropy triggering the landslides. This analysis should serve as a guide for forecasting landslide-triggering conditions in Rwanda. |
| format | Article |
| id | doaj-art-188411a47f7345d1b2c9065dd2890d23 |
| institution | Kabale University |
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| language | English |
| publishDate | 2024-09-01 |
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| series | GeoHazards |
| spelling | doaj-art-188411a47f7345d1b2c9065dd2890d232024-12-27T14:28:11ZengMDPI AGGeoHazards2624-795X2024-09-01541018103910.3390/geohazards5040049Exceptional Cluster of Simultaneous Shallow Landslides in Rwanda: Context, Triggering Factors, and Potential WarningsFils-Vainqueur Byiringiro0Marc Jolivet1Olivier Dauteuil2Damien Arvor3Christine Hitimana Niyotwambaza4Centre National de la Recherche Scientifique (CNRS), Géosciences Rennes, ULR 6118, Université Rennes, F-35000 Rennes, FranceCentre National de la Recherche Scientifique (CNRS), Géosciences Rennes, ULR 6118, Université Rennes, F-35000 Rennes, FranceCentre National de la Recherche Scientifique (CNRS), Géosciences Rennes, ULR 6118, Université Rennes, F-35000 Rennes, FranceCentre National de la Recherche Scientifique (CNRS), Laboratory Littoral – Environnement – Télédétection – Géomatique (LETG), UMR 6554, Université Rennes 2, F-35000 Rennes, FranceMinistry in Charge of Emergency Management (MINEMA), KN3 Rd, Kigali P.O. Box 4386, RwandaRwanda, in eastern tropical Africa, is a small, densely populated country where climatic disasters are often the cause of considerable damage and deaths. Landslides are among the most frequent hazards, linked to the country’s peculiar configuration including high relief with steep slopes, humid tropical climate with heavy rainfall, intense deforestation over the past 60 years, and extensive use of the soil for agriculture. The Karongi region, in the west-central part of the country, was affected by an exceptional cluster of more than 700 landslides during a single night (6–7 May 2018) over an area of 100 km<sup>2</sup>. We analyse the causes of this spectacular event based on field geological and geomorphology investigation and CHIRPS and ERA5-Land climate data. We demonstrate that (1) the notably steep slopes favoured soil instability; (2) the layered soil and especially the gravelly, porous C horizon allowed water storage and served as a detachment level for the landslides; (3) relatively low intensity, almost continuous rainfall over the previous two months lead to soil water-logging; and (4) acoustic waves from thunder or mechanical shaking by strong wind destabilized the water-logged soil through thixotropy triggering the landslides. This analysis should serve as a guide for forecasting landslide-triggering conditions in Rwanda.https://www.mdpi.com/2624-795X/5/4/49natural hazardrainfall-induced landslideseastern Africathunderstormshigh population density |
| spellingShingle | Fils-Vainqueur Byiringiro Marc Jolivet Olivier Dauteuil Damien Arvor Christine Hitimana Niyotwambaza Exceptional Cluster of Simultaneous Shallow Landslides in Rwanda: Context, Triggering Factors, and Potential Warnings GeoHazards natural hazard rainfall-induced landslides eastern Africa thunderstorms high population density |
| title | Exceptional Cluster of Simultaneous Shallow Landslides in Rwanda: Context, Triggering Factors, and Potential Warnings |
| title_full | Exceptional Cluster of Simultaneous Shallow Landslides in Rwanda: Context, Triggering Factors, and Potential Warnings |
| title_fullStr | Exceptional Cluster of Simultaneous Shallow Landslides in Rwanda: Context, Triggering Factors, and Potential Warnings |
| title_full_unstemmed | Exceptional Cluster of Simultaneous Shallow Landslides in Rwanda: Context, Triggering Factors, and Potential Warnings |
| title_short | Exceptional Cluster of Simultaneous Shallow Landslides in Rwanda: Context, Triggering Factors, and Potential Warnings |
| title_sort | exceptional cluster of simultaneous shallow landslides in rwanda context triggering factors and potential warnings |
| topic | natural hazard rainfall-induced landslides eastern Africa thunderstorms high population density |
| url | https://www.mdpi.com/2624-795X/5/4/49 |
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