Neotectonic fault mapping at the Gibraltar Strait Tunnel area, Bolonia Bay (South Spain)

Abstract A Map of Fault Activity has been developed for preliminary engineering planning related to the construction of an underwater fixed link-route between Africa and Europe at the Gibraltar Strait Sector, in South Spain (the Gibraltar Tunnel). Main criteria used in fault activity evaluation have been seismicity, surface faulting, geomorphology of fault traces, identification of paleoseismic ground failures, and evaluation of differential uplift rates on coastal segments separated by large-scale inland faults. The aim of this work is the development of comprehensive methodology for the graphic representation (chart-format) of geo-hazards related to ground conditions, seismicity and fault activity. The criteria management is mainly focused on the establishment of the seismic or aseismic character of individual fault traces. For this the age of the last deformational event, and slip rates (where possible) are taken into account, but their classification as active or inactive structures is avoided. From this study, the Cabo de Gracia strike-slip fault (NE–SW) can be catalogued as active during at least the last 128 ka BP, and as a probable seismic source of moderate events (mb

[1]  C. Rodríguez,et al.  Paleoesfuerzos en las cuencas de antepaís en la parte noroccidental del arco de gibraltar (mioceno superior-actualidad) , 1998 .

[2]  J. Mezcua,et al.  Isoseismal map of the 1755 Lisbon earthquake obtained from Spanish data , 1979 .

[3]  M. Thiry,et al.  Seismically induced deformation structures in Oligocene shallow-marine and aeolian coastal sands (Paris Basin) , 1992 .

[4]  J. Balanya,et al.  Les directions structurales dans le Domaine d'Alborán de part et d'autre du Détroit de Gibraltar , 1987 .

[5]  Richard G. Gordon,et al.  Effect of recent revisions to the geomagnetic reversal time scale on estimates of current plate motions , 1994 .

[6]  B. Vliet-Lanoë,et al.  Neotectonic and seismic activity in the Armorican and Cornubian Massifs: Regional stress field with glacio-isostatic influence? , 1997 .

[7]  J. Morales,et al.  Moment tensor solutions for small and moderate earthquakes in the Ibero‐Maghreb region , 2003 .

[8]  Homa J. Lee,et al.  Geotechnical properties and preliminary assessment of sediment stability on the continental slope of the northwestern Alboran Sea , 1992 .

[9]  P. Vaskou,et al.  Proposal for classification of fault activity in an intraplate collision setting: Definitions and examples , 1991 .

[10]  G. De Vicente,et al.  The recent (upper Miocene to Quaternary) and present tectonic stress distributions in the Iberian Peninsula , 2000 .

[11]  António Ribeiro,et al.  Stress pattern in Portugal mainland and the adjacent Atlantic region, West Iberia , 1996 .

[12]  Antonio Jabaloy,et al.  Stress and palaeostress in the Betic-Rif cordilleras (Miocene to the present) , 1993 .

[13]  F. Audemard,et al.  Survey of liquefaction structures induced by recent moderate earthquakes , 1991 .

[14]  R. Weijermars.  Geology and tectonics of the Betic Zone, SE Spain , 1991 .

[15]  P. García,et al.  Estructuras sedimentarias de deformación en el Mioceno superior-Cuaternario de la Cordillera Bética , 2000 .

[16]  O. Reina.  Holocene aeolian phases and human settlements along the Atlintic Coast of Southern Spain. de F. Borja, C. Zazo, C. J. Dabrio, F. Díaz del Olmo, J. L. Goy y J. Lario , 1999 .

[17]  A. Muñoz-Martín,et al.  Determination of present-day stress tensor and neotectonic interval in the Spanish Central System and Madrid Basin, central Spain , 1996 .

[18]  T. Reston.  Shear in the lower crust during extension: not so pure and simple , 1990 .

[19]  M. Esteras,et al.  Evolución morfológica y estratigráfica plio-cuaternaria del Umbral de Camarinal (Estrecho de Gibraltar) basada en sondeos marinos. , 2000 .

[20]  T. Bardají,et al.  Archaeoseismic record at the ancient Roman City of Baelo Claudia (Cadiz, south Spain) , 2005 .

[21]  C. Galdeano,et al.  Geologic evolution of the Betic Cordilleras in the Western Mediterranean, Miocene to the present , 1990 .

[22]  Pierre Sillières,et al.  Baelo Claudia: una ciudad romana de la Bética , 1997 .

[23]  A. González,et al.  Coastal uplift in continental collision plate boundaries: data from the Last Interglacial marine terraces of the Gibraltar Strait area (south Spain) , 1999 .