Anne Domzig

Comment on “Zemmouri earthquake rupture zone (Mw 6.8, Algeria): Aftershocks sequence relocation and 3D velocity model” by A. Ayadi et al.

Although often difficult to characterize, the relationship between a seismic rupture, its aftershock sequence, and cumulative subsurface or surface faulting or folding is an important challenge to modern seismology and seismotectonics. Among other benefits, it helps document fault length, slip, and magnitude relationships, reconstruct the evolution of the rupture process through historical and prehistorical times and identify the complexity of the deformation in its path toward the surface. This approach is a prerequisite to any seismic hazard assessment but is particularly difficult for faults whose surface trace projects offshore. A specific effort to identify and quantify the source parameters of large earthquakes in coastal areas is therefore needed, not only in subduction zones but also in areas of slow rate and/or diffuse deformation.

Submarine Landslides Along the Algerian Margin: A Review of Their Occurrence and Potential Link with Tectonic Structures

The Algerian continental margin, a Cenozoic passive margin along the plate boundary between Eurasia and Africa presently reactivated in compression, is one of the most seismically active areas in the Western Mediterranean, having experienced several moderate to strong earthquakes in the coastal zone during the last century. The morphology of the continental slope offshore Algeria is steep and dominated by the presence of numerous canyons of variable size and sea-floor escarpments that are probably the seafloor expression of active thrust-folds. Numerous submarine landslides are present along these structures, as well as asso-ciated with salt diapirs in the abyssal plain. Submarine landslides are expressed by seafloor scars (usually of small size) and subsurface or buried acoustically chaotic/ transparent units interpreted as mass transport deposits (MTD). Compared with the most recent (superficial) small size of slide scars, buried MTDs seem to be of larger size, possibly suggesting a change in the functioning of gravity-driven processes in the margin throughout the Plio-Quaternary.

Plio-Quaternary deformation pattern along the Algerian margin: insights from multibeam bathymetry and seismic reflection profiles (Maradja 1 and Samra cruises)

Los braquiopodos retzidinos son una fraccion menor de las faunas devonicas de la CordilleraCantabrica (Norte de Espana). Aparte de un par de formas raras, impublicadas, del Praguiense delDominio Palentino y del Emsiense inferior del Astur-Leones, proximas al genero Rhynchospirina, ellinaje alcanzo su maximo de diversidad en la parte superior del Emsiense, con dos especies del generoRetzia, R. adrieni y R. cf. prominula, Cooperispira subferita y, quizas, una forma impublicada dePlectospira. El grupo no es conocido en el resto del Devonico y reaparece en el Pensilvaniense con algunasformas del genero Hustedia. En este trabajo se propone un nuevo taxon de la Familia Retziidae,Argovejia n.gen., de la parte final del Emsiense superior de Asturias y Leon, constituido por su especietipo,A. talenti n.sp. y, quizas, por las formas del Emsiense superior del Macizo Armoricano (Francia)Retzia haidingeri var. armoricana y Retzia haidingeri var. dichotoma.The Ronda Depression is filled by Neogene sediments on the boundary between Subbeticreliefs, with NE-SW structural trends, and the frontal Subbetic Chaotic Complexes. The folding stylein the Subbetic Units of Western Betics is strongly controlled by the rheology of the rocks: thick andmassive beds of Jurassic limestones over Triassic marls and gypsum with plastic behaviour. Main deformationstructures in the sedimentary infill of the Ronda depression are simultaneous box folds withNNE-SSW and WNW-ESE trends that only affect its southwestern part. This distribution of folds isa consequence of the inherited fold trend that affected the basement during Early Burdigalian age.