TITLE:
Analysis of Lineaments for Identifying Potential Subsidence Zones in Conakry: The Case of the Former Municipality of Ratoma (Guinea)
AUTHORS:
Ninamou Tökpö, Kolié Labilé, Elégbédé Manou Bernadin
KEYWORDS:
Ratoma, Remote Sensing, Lineament, AHP Method, Risk of Subsidence
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.14 No.2,
January
30,
2026
ABSTRACT: Ratom was one of the five communes of Conakry (Guinea) before the administrative division of 2025. It faces risks of soil subsidence. To identify areas susceptible to subsidence or collapse, lineament analysis was used to locate areas with low mechanical resistance. This study proposes a multidisciplinary methodological approach to assess and map subsidence risks in the study area. It combines remote sensing techniques, geostatistical analysis, geotechnical methods, and multicriteria decision-making methods. Automatic extraction of lineaments from a Landsat 8 image identified 1011 lineaments. Analysis reveals that 68% of these are minor lineaments, while 12% are major lineaments. This may reflect geological discontinuities that impact soil stability. After validation by comparison with the road and hydrographic networks, these lineaments were analyzed using a variogram model to produce a map of risk areas. At the same time, data from geotechnical tests on 11 samples were used to measure paramters such as water content, grain size, and Atterberg limits. The liquidity index (LI) proved to be a determining factor in assessing the risk of subsidence. In addition, a multi-criteria approach using the AHP method took five factors into account: fracture density, mechanical strength, liquidity index, slope, and altitude. The map obtained from this analysis shows that 49.06% of the surface area of Ratoma is exposed to a high risk of subsidence. Critical areas such as Kobaya, Kiroti, and the Kakimbo-University axis, which often experience subsidence, are well located within the identified risk areas. This approach has made it possible to produce a tool for sustainable urban planning and risk prevention in this municipality.