Structural and geomorphological controls of the present-day landslide in the Moulares phosphate mines (western-central Tunisia)

Present-day deformations occurring within both waste dump and bedrock in the Northern Table mine of Moulares, western central Tunisia, show complex landslides of kilometric dimensions. Rock bodies in this mine slide due to the shear stress concentration along a complex sliding surface. As a result of gravity displacement, these rocks display diverse associate structures such as detachment, open fractures, folds, and striated thrust planes. Interaction between predisposition factors (inherited structures, topography, slope, gravity) and triggering factors (artificial vibrations and seismotectonic activity) provided favourable conditions for the sliding. Sloping fractured ground, marly lithology and meteoric water act further to exacerbate the instability in the ground and encourage rock failure. Additionally, the seismic hazard due to the sustained tectonic activity of the Gafsa fault and the vibrations due to explosive detonation can together trigger significant landslide movement.