Evidence of seismites in coastal Quaternary deposits of western Oranie (northwestern Algeria)

Mohamed Amine Boukhedimi (1) , Amina Louni-Hacini (1) , Youcef Bouhadad (2) , J.F. Ritz (3) , Djamel Machane (2) , Azzeddine Benhamouche (1) , Hamid Bourenane (1)

1 USTHB - Université des Sciences et de la Technologie Houari Boumediene = University of Sciences and Technology Houari Boumediene [Alger]
2 National Center of Applied Research in Earthquake Engineering
3 Géosciences Montpellier

Coastal Quaternary deposits of western Oranie show typical soft-sediment deformations including sedimentary dykes, sand volcanoes, sismoslumps, thixotropic bowls, thixotropic wedges, diapir-like structures, and faults grading. Field observations indicate that these deformations exist at several levels of the studied deposits along the west Oranian coast. This study demonstrated that these structures are earthquakes-related, by analysis of potential trigger sources. Several arguments demonstrate the seismic origin: the depositional environment rich in water that located in an active tectonic region, the thixotropic nature of deformations and their large vertical and horizontal diffusion in the Quaternary series consistent with a seismic recurrence. This allows characterizing these Quaternary soft-sediment deformations as seismites that were triggered by earthquakes.

Mots clés: Soft-sediment deformations; Quaternary deposits; Active tectonic; Thixotropic nature; Seismites; Earthquakes; Oranie

Domaines: Tectonique

Mohamed Amine Boukhedimi, Amina Louni-Hacini, Youcef Bouhadad, J.F. Ritz, Djamel Machane, et al.. Evidence of seismites in coastal Quaternary deposits of western Oranie (northwestern Algeria). Journal of Seismology, 2017, 21 (3), pp.539-549. ⟨10.1007/s10950-016-9616-2⟩. ⟨hal-01560975⟩