Recent structures in the Alboran Ridge and Yusuf fault zones based on swath bathymetry and sub-bottom profiling: evidence of active tectonics

Geo-Marine Letters - Tập 31 - Trang 19-36 - 2010
Pedro Martínez-García1, Juan I. Soto2, Menchu Comas1
1Instituto Andaluz de Ciencias de la Tierra (CSIC and University of Granada), Facultad de Ciencias, Granada, Spain
2Instituto Andaluz de Ciencias de la Tierra (CSIC and University of Granada) and Departamento de Geodinámica, Facultad de Ciencias, Granada, Spain

Tóm tắt

The seafloor of the Alboran Sea in the western Mediterranean is disrupted by deformations resulting from convergence between the African and Eurasian plates. Based on a compilation of existing and new multibeam bathymetry data and high-resolution seismic profiles, our main objective was to characterize the most recent structures in the central sector, which depicts an abrupt morphology and was chosen to investigate how active tectonic processes are shaping the seafloor. The Alboran Ridge is the most prominent feature in the Alboran Sea (>130 km in length), and a key element in the Gibraltar Arc System. Recent uplift and deformation in this ridge have been caused by sub-vertical, strike-slip and reverse faults with associated folding in the most recent sediments, their trend shifting progressively from SW–NE to WNW–ESE towards the Yusuf Lineament. Present-day transtensive deformation induces faulting and subsidence in the Yusuf pull-apart basin. The Alboran Ridge and Yusuf fault zones are connected, and both constitute a wide zone of deformation reaching tens of kilometres in width and showing a complex geometry, including different active fault segments and in-relay folds. These findings demonstrate that Recent deformation is more heterogeneously distributed than commonly considered. A narrow SSW–NNE zone with folding and reverse faulting cuts across the western end of the Alboran Ridge and concentrates most of the upper crustal seismicity in the region. This zone of deformation defines a seismogenic, left-lateral fault zone connected to the south with the Al Hoceima seismic swarm, and representing a potential seismic hazard. Newly detected buried and active submarine slides along the Alboran Ridge and the Yusuf Lineament are clear signs of submarine slope instability in this seismically active region.

Tài liệu tham khảo

Ait Brahim L, Chotin P, Hinaj S, Abdelouafi A, El Adraoui A, Nakcha C, Dhont D, Charroud M, Sossey Alaoui F, Amrhar M, Bouaza A, Tabyaoui H, Chaouni A (2002) Paleostress evolution in the Moroccan African margin from Triassic to present. Tectonophysics 357:187–205

Alonso B, Maldonado A (1992) Plio-quaternary margin growth patterns in a complex tectonic setting: Northeastern Alboran Sea. Geo Mar Lett 12(2/3):137–143. doi:10.1007/BF02084924

Bárcenas P, Vázquez JT, Díaz del Río V, Fernández-Salas LM (2004) Geomorfología del Banco de la Isla de Alborán. Geo-Temas 6:209–212

Benmakhlouf M, Galindo-Zaldívar J, Chalouan A, Sanz de Galdeano C, Ahmamou M, López-Garrido AC (2005) Cinemática y paleoesfuerzos en la zona de falla transcurrente de Jebha-Chrafate (Rif septentrional, Marruecos). Geogaceta 38:71–74

Bourgois J, Mauffret A, Ammar A, Demnati A (1992) Multichannel seismic data imaging of inversion tectonics of the Alboran Ridge (western Mediterranean Sea). Geo Mar Lett 12(2/3):117–122. doi:10.1007/BF02084921

Campos J, Maldonado A, Campillo AC (1992) Post-Messinian evolutional patterns of the central Alboran Sea. Geo Mar Lett 12(2/3):173–178. doi:10.1007/BF02084929

Chalouan A, Michard A, El Kadiri K, Negro F, Frizon de Lamotte D, Soto JI, Saddiqi O (2008) The Rift Belt. In: Michard A, Saddiqi O, Chalouan A, Frizon de Lamotte D (eds) The Rif belt continental evolution: the geology of Morocco. Structure, stratigraphy, and tectonics of the Africa-Atlantic-Mediterranean triple junction. Lecture in Earth Sciences, vol 116. Springer, Berlin, pp 203–302

Comas MC, Zahn R, Klaus A, Shipboard Scientific Party (1996) Proceedings of the Ocean Drilling Program, initial reports 161. Ocean Drilling Program, College Station

Fernández-Ibáñez F, Soto JI (2008) Crustal rheology and seismicity in the Gibraltar Arc (western Mediterranean). Tectonics 27:TC2007. doi:10.1029/2007TC002192

Fernández-Ibáñez F, Soto JI, Zoback MD, Morales J (2007) Present-day stress field in the Gibraltar Arc (western Mediterranean). J Geophys Res 112:B08404. doi:10.1029/2006JB004683

Galindo-Zaldívar J, Chalouan A, Azzouz O, Sanz de Galdeano C, Anahnah F, Ameza L, Ruano P, Pedrera A, Ruiz-Constán A, Marín-Lechado C, Benmakhlouf M, López-Garrido AC, Ahmamou M, Saji R, Roldán-García FJ, Akil M, Chabli A (2009) Are the seismological and geological observations of the Al Hoceima (Morocco, Rif) 2004 earthquake (M = 6.3) contradictory? Tectonophysics 475:59–67

Maestro-González A, Bárcenas P, Vázquez T, Díaz-del-Río V (2008) The role of basement inheritance faults in the recent fracture system of the inner shelf around Alboran Island, Western Mediterranean. Geo Mar Lett 28(1):53–64. doi:10.1007/s00367-007-0089-8

Martín-Serrano A (2005) Mapa geomorfológico de España y del margen continental a escala 1:1.000.000. Instituto Geológico y Minero de España, Madrid

Masana E, Martínez-Díaz JJ, Hernández-Enrile P, Santanach P (2004) The Alhama de Murcia fault (SE Spain), a seismogenic fault in a diffuse plate boundary: seismotectonic implications for the Ibero-Magrebian region. J Geophys Res 109:B01301. doi:10.1029/2002JB002359

MediMap Group (2008) Morpho-bathymetry of the Mediterranean Sea. CIESM/Ifremer special publication, atlases and maps, two maps at 1/2000000. Editions Ifremer, Plouzané

Muñoz A, Ballesteros M, Montoya I, Rivera J, Acosta J, Uchupi E (2008) Alboran basin, Southern Spain. Part I: geomorphology. Mar Petrol Geol 25:59–73

Soto JI, Manzano FJ (2002) Geometría y cinemática de fallas recientes en el margen septentrional del Mar de Alborán (Sector de Maro, Provincia de Málaga). Geogaceta 31:139–142

Stich D, Ammon CJ, Morales J (2003) Moment tensor solutions for small and moderate earthquakes in the Ibero-Maghreb region. J Geophys Res 108:2148. doi:10.1029/2002JB002057

Vázquez JT (2001) Estructura del margen septentrional del Mar de Alborán. PhD Thesis, Universidad Complutense de Madrid, Madrid

Willet A (1991) Marine geophysical investigations of the Alboran Sea. PhD Thesis, Oxford University, Oxford