The geometry and evolution of a transpressional strike-slip system: the Carboneras fault, SE Spain

Abstract

The Carboneras fault system is a 40 km long, 1 km wide Neogene NE-SW-trending left-lateral transpressional strike-slip fault system which is part of the Trans-Alboran shear zone in SE Spain. The Carboneras fault system is an anastomosing array of sub-vertical, individual fault planes or fault zones which surround pods or lenses of less intensely strained rocks. Displacements along the individual fault planes exhibit reverse components of slips and form positive flower structures. Faults have either sharp boundaries or wider bands of gouge, typically a few metres thick and are hundreds of metres in length. Second-order fault splays are well developed and usually exhibit P-shear rather than Riedel-shear orientations. These are interpreted to be related to the transpressional displacement and may also characterize other oblique convergent zones elsewhere. The second-order faults are interpreted to have formed as shear strain increased along the first-order fault and was transferred laterally to branch segments. This process produced pods, or shear lenses, bounded by the fault segments. The length to width aspect ratios of the shear lenses were found to be scale-independent across five orders of magnitude with the most common values between 3:l and 6:l. A model is proposed for the development of the fault zone by incremental finite displacements along the segmented fault surfaces. This model is based on field evidence that displacement switched with time from one fault strand to another.

Scenarios for earthquake-generated tsunamis on a complex tectonic area of diffuse deformation and low velocity: The Alboran Sea, Western Mediterranean

“…We have included the onshore segment due to its proximity to the coast, therefore dividing the Carboneras Fault into three segments: the onshore segment, here called "Carboneras Fault Northern" (CFN); the northern offshore segment; "Carboneras Fault Central" (CFC) and the southern offshore segment, "Carboneras Fault Southern" (CFS). The characteristics of the onshore segment are very similar to those of the northern offshore segment (Keller et al, 1995;Grana et al, 2006;Moreno et aI., 2008).…”

Acoustic and seismic imaging of the Adra Fault (NE Alboran Sea): in search of the source of the 1910 Adra earthquake

“…Marín-Lechado et al, 2005). These events have been mainly attributed to the motion along the Carboneras fault system (Keller et al, 1995). On the other hand, it has been suggested that the 1910 Adra Earthquake (M w = 6.1, I 0 = VIII MSK in Adra) was probably generated by N120-N130 trending faults offshore (Stich et al, 2003b), although, the tectonic source of this earthquake is still unknown.…”

Recent and active faults and folds in the central-eastern Internal Zones of the Betic Cordillera

“…4A; Galindo-Zaldívar, 1986). fault segment runs from Los Guardianes, near Polopos village, to the southern boundary of Sierra Cabrera antiform with an ENE-WSW trend, being called the Polopos fault (Keller et al, 1995) or the South Gafarillos fault ( Fig. 4; Giaconia et al, 2012).…”

“…3C and 4C). Southdipping reverse faults form the north boundary of the Sierra Cabrera (Booth-Rea et al, 2004), locally affecting Quaternary sediments (Sanz de Galdeano, 1987), and north-dipping reverse faults constitute the southern edge of the Sierra (Keller et al, 1995).The CuaTeNeo (Cuanti¿FLDFLyQ GH OD 7HFWyQLFD DFWXDO \ 1HRWHFWyQLFD *36 QRQ permanent network was installed in 1996 to quantify the deformation in the Eastern Betic Cordillera. The network consists of 15 monuments covering an area of 120x50 km in Murcia and Almería (Colomina et al, 1998;Khazaradze et al, 2007 and2008).…”