Tectonique actuelle et récente et risque sismique de la région de Constantine

Abstract

Northeastern Algeria is periodically subject to earthquakes. While often localized within the Tellian belt, they can also occur in the Atlas foothills and continental basins. Understanding the mechanisms behind these natural phenomena requires tracing them back to their origins—specifically, the geological faults that, under the influence of tectonic stress, remain locked until they reach a breaking point, triggering an earthquake. This process allows for correlation with other existing geological structures, providing insights essential for the general management and forecasting of seismic events. However, this type of analysis faces several challenges, notably the scarcity and imprecision of existing geological maps (including geological boundaries, dating, etc.), the prevalence of terrigenous facies, and the degradation of the morphological expressions of deformation. The western part of the Constantine region serves as a telling example. The approach taken here is both multidisciplinary and multi-scalar. It leverages the specific morphological and geological anomalies of the region to identify recent and ongoing deformations, applying criteria related to active tectonics. The body of this thesis is structured around four key areas: • Identifying the topographical expressions of deformation. • Characterizing and quantifying horizontal and vertical movements, and their relationship to fracture networks. • Analyzing the historical seismicity of the region. • Examining the interplay between neotectonics, deformation, and seismicity. Finally, the analysis will also examine certain impacts of neotectonics, such as significant uplift, the fragmentation of the landscape, valley incision, and subsidence.