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A Geophysical Study of the Carcavai Fault Zone, Portugal

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Abstract

The Algarve province is located a few hundred kilometres north of the crossing of the E–W Eurasia–Africa plate boundary in an area of diffuse seismicity and broad deformation. It is characterised by a moderate seismicity, with some important historical and instrumental earthquakes causing loss of lives and significant material damages. The area is affected not only by plate boundary earthquakes but also by moderate to large events generated by local sources. The assessment of onshore local sources is, therefore, of vital importance for an evaluation of the regional seismic hazard. This paper discusses the application of geophysical data to the study of the Carcavai fault zone, an outcropping structure more than 20 km long which is seen to deform sediments of the Plio-Quaternary age. The location of some sectors of the fault zone, as well as the vertical offsets of the structure, are still to be confirmed. In order to estimate these and to study the geometry of the fault zone at depth, geophysical data were acquired together with new geological data. Where the location of the fault was less certain, EM and seismic reflection profiles with coarse spatial sampling were carried out. After the detailed location of the fault zone, seismic reflection profiles with a more dense spatial resolution were acquired. The integrated interpretation of the geological and geophysical data confirmed the presence of a large fault zone. The total fault length is still unknown as its extension offshore is still being studied. Together with estimated values of the throw obtained, this data set has improved understanding the seismic hazard in the area by providing more refined estimates of co-seismic rupture, maximum expected earthquake and return periods.

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References

  • Antunes, M. T. and Pais, J. (1993), The Neogene of Portugal, Ciências da Terra (UNL). 12, 7-22.

  • Benson, A. K. (1989), Depth imaging seismic data to help delineate gas reservoirs in southwest Wyoming, Wyoming Geological Association Guidebook. 40, 231-240.

  • Benson, A. K., Mustoe, N. B. (1989), Integrated geophysical approach to delineating shallow, concealed faults along the Wasatch Front, SEG Expanded Abstracts. 2, 885-887.

  • Benson, A. K., Mustoe, N. B. (1991), Delineating concealed faults and shallow subsurface geology along the Wasatch Front, Utah, USA, by integrating geophysical and trench data, Quarterly Journal of Engineering Geology. 24, 375-387.

  • Cachão, M. (1995), Utilização de nanofósseis calcários em biostratigrafia, paleocenografia, e paleocologia. Aplicações ao neogénico do Algarve (Portugal) e do Mediterrâneo Ocidental (ODP 653) e a problemática de Coccolithus pelagicus, Ph.D. Thesis, University of Lisbon, Portugal.

  • Campbell, F.M., Kaiser, A., Horstmeyer, H., Green, A., Ghisetti, F., Gorman, A.R., Finnemore, M., Nobes, D.C. (2010), Processing and preliminary interpretation of noisy high-resolution seismic reflection/refraction data across the active Ostler Fault zone, South Island, New Zealand, Journal of Applied Geophysics. 70, 332-342.

  • Carrilho, F., Senos, L., Fitas, A., Borges, F. (1997), Estudo da Sismicidade do Algarve e Zona Atlântica Adjacente, 3rd Meeting on Seismology and Engineering Seismology, IST, Lisbon, Portugal, Expanded Abstracts, 59-67.

  • Carrilho, F., Teves-Costa, P., Morais, I., Pagarete, J., Dias, R. (2004), GEOALGAR Project: First Results on Seismicity and Fault-plane Solutions, Pure and Applied Geophysics. 161, 589-606.

  • Carvalho, J. (2003), Sísmica de alta resolução aplicada à prospecção, geotecnia e risco sísmico, Ph.D. Thesis, University of Lisbon, Portugal.

  • Carvalho, J., Torres, L., Rocha, R., Dias, R., Mendes-Victor, L. (2006), A Geophysical Study of the S. Marcos-Quarteira Fault, Portugal, Journal of Applied Geophysics. 60, 2, 153-164.

  • Carvalho, João, Dias, Ruben, Pinto, Carlos, Leote, Jaime, Mendes-Victor, Luís (2008), A Soil Classification for Seismic Hazard Assessment and Mitigation of the Algarve, 14Th World Conference on Earthquake Engineering, Beijing, China, 7 pp.

  • Carvalho, J., Ghose, R, Pinto, C., Borges, J. (2009), Characterization of a Concealed Fault Zone Using P and S-wave Seismic Reflection Data, Extended Abstracts of the EAGE Near Surface 2009/15Th Meeting of Environmental and Engineering Geophysics, Dublin, Ireland, A14, 5 pp.

  • Catuneanu, O., Bhattacharya, J. P., Blum, Dalrymple, M. D., Eriksson, P. G., Fielding, C. R., Fisher, W. L., Galloway, W. E., Gianolla, P., Gibling, M. R., Giles, K. A., Holbrook, J. M., Jordan, R., Kendall, C,G.St.C., Macurda, B., Martinsen, O. J., Miall, A. D., Nummedal, D., HW. Posamentier, H. W., Pratt, B. R., Shanley, K. W., Steel, R. J., Strasser, A. and M. E. Tucker (2010), Sequence stratigraphy: common ground after three decades of development, First Break. 28, 41-52.

  • Cox, M., Static corrections for seismic reflection surveys (Society of Exploration Geophysicists, Tulsa 1999).

  • Dias, R. P. (2001), Neotectónica da Região do Algarve, PhD Thesis, University of Lisbon, Portugal.

  • Dias, R. P., Cabral, J. (1995), Actividade Neotectónica na região do Algarve, IV Congresso Nacional de Geologia, Universidade do Porto, Faculdade de Ciências Museu e Laboratório Mineralógico e Geológico, Porto, Expanded Abstracts, 241-245.

  • Dias, R.P., Cabral, J. (2002a) Neotectonic activity of the Algarve region (S of Portugal). Comunicações do Instituto Geológico e Mineiro, Tomo 89, 193-208.

  • Dias, R. P., Cabral, J. (2002b), Interpretation of recent structures in an area of cryptokarst evolution-neotectonic versus subsidence genesis, Geodinamica Acta. 15, 233-248.

  • Dias, R. P.; Terrinha, P.; Carvalho, J.; Ramalho, E.;Vicente, J.; Pinto, C. Noiva, J.; Ressurreição, R.; Roque, C.; Duarte, J.; Rego, J.; Gomes, F.; Caneiras, F.; Marquilhas J. (2008) Sismotectónica do Algarve. Final Report of the ERSTA Protocol (Estudo do Risco Sísmico e de Tsunamis do Algarve), Instituto Nacional de Engenharia, Tecnologia e Inovação (INETI) report for the National Authority for Civil Protection (ANPC) (unpublished).

  • Farrell, R. C., and Euwema, R. M. (1984), Refraction Statics, IEEE, 72, no.10, 1316-1329.

  • Gazdag, J (1978), Wave-equation migration by phase shift, Geophysics. 43, 1342-1351.

  • Geirnaert, W., Van Beeres, P. H., De Vries, J. J., Hoogeveen, H. (1982) Geo-electric survey of the miocene aquifer between Quarteira and Olhão, Algarve, Portugal, In Hidrogeologic studies in the East Algarve, Portugal. (Eds. W. Geirnaert P. H. Van Beeres and J. J. De Vries). (A contribution to the III Semana de Hidrogeologia, Lisboa, Portugal 1982) pp. 2-22.

  • Geonics Ltd (1990) EM34-3 and EM34-3XL Operating Instructions.

  • Hale, D. (1984), Dip-moveout by Fourier transform, Geophysics. 49, 741-757.

  • Harris, James B. (2009), Hammer-Impact SH-Wave Seismic Reflection Methods in Neotectonic Investigations: General Observations and Case Histories from the Mississippi Embayment, U.S.A., Journal of Earth Science. 20, 513-525.

  • Hornbostel, S. (1991), Spatial prediction filtering in the t-x and f-x domain, Geophysics. 56, 2019-2026.

  • Kilty, K. T., Norris, R. A., McLamore, W. R., Hennon, K. R., Euge, K. (1986) Seismic Refraction at Horse Mesa Dam: An application of the generalized reciprocal method, Geophysics. 51, 266-275.

  • Legoinha, P. (2003), Upper Miocene planktonic foraminifera from Algarve. Chronostratigraphical implications, Ciências da Terra (UNL). 15, 199-208.

  • Liner, C., L., Liner, J., L. (1997), Application of GPR to a site investigation involving shallow faults, The Leading Edge. 16, 1649-1652.

  • Mair, J., A., Green, A., G. (1981), High-resolution seismic reflection profiles reveal fracture zones with a homogeneous granite batholith, Nature. 294, 439-442.

  • Manuppella, G. (1992), Carta Geológica da Região do Algarve, escala 1: 100.000. (coord. G. Manuppella), Serviços Geológicos de Portugal.

  • Manuppella, G., Ramalho, M., Telles Antunes, M., Pais, J. (2007) Notícia explicativa da folha 53-A (Faro), na escala 1/50 000. Serviços Geológicos de Portugal, 52 pp.

  • Miller, R. D., Steeples, D., W., Myers, P., B. (1990), Shallow seismic-reflection survey across the Meers fault, Oklahoma, Geological Society of America Bulletin. 102, 18-25.

  • Mitchum, R. M. Jr, Vail, P. R., Sangree, J. B., Seismic Stratigraphy and Global Changes of Sea Level, Part 6: Stratigraphic Interpretation of Seismic Reflection Patterns in Deposicional Sequences, In Seismic Stratigraphy–applications to hydrocarbon exploration (American Association of Petroleum Geologists- Memoir 26, Tulsa 1977) pp. 117-134.

  • Mougenot, D., Geologia da Margem Portuguesa (Instituto Hidrográfico, Lisboa 1989).

  • Moura, D., Boski, T. (1999), Unidades litostratigráficas do Pliocénico e Plistocénico no Algarve, Comun. Inst. Geol. e Mineiro. 86, 85-106.

  • Noiva, J. (2009), Caracterização das estruturas tectónicas activas da região sul de Portugal com recurso a ferramentas SIG: O caso da falha de São Marcos-Quarteira, Msc Thesis, Universidade Nova de Lisboa, 112 pp.

  • Noiva, J., Duarte, H., Terrinha, P., Gonçalves, D. (2010), Holocene morphologic changes offshore the Quarteira region, Algarve, south Portugal, EGU Meeting, Vienna, Áustria, EGU2010-12992.

  • Pais, J., Legoinha, P., Elderfield, H., Sousa, L., Estevens, M. (2000), The Neogene of Algarve (Portugal), Ciências da Terra (UNL). 14, 277-288.

  • Palmer, D. (1981), An introduction to the generalized reciprocal method of seismic refraction interpretation, Geophysics. 46, 1508-1518.

  • Palmer, D., The generalized reciprocal method of seismic refraction interpretation (Society of Exploration Geophysicists, Tulsa 1980).

  • Ressurreição, R. (2009), Estudos de Neotectónica na falha de Carcavai (Algarve): contribuição para a caracterização desta estrutura e de paleossismitos prováveis associados, MsC Thesis, University of Lisbon, 121 pp.

  • Rey, J., Dinis, J.L., Callapez, P., Cunha, P.P. (2006) Da rotura continental à margem passiva. Composição e evolução do Cretácico de Portugal, Cadernos de Geologia de Portugal. INETI, 75 pp.

  • Ribeiro, A., Soft Plate and Impact Tectonics (Springer Verlag, New York 2002).

  • Rosas, F.M., Duarte, J.C., Terrinha, P., Valadares, V. & Matias, L. (2008), Morphotectonic characterization of major bathymetric lineaments in Gulf of Cadiz (Africa-Iberia plate boundary): Insights from analogue modeling experiments, Marine Geology. 261, 33-47.

  • Santos, F. M. (2004), 1-D laterally constrained inversion of EM34 profiling data, Journal of Applied Geophysics. 56, 123-134.

  • Shtivelman, V., Frieslander, U., Zilberman, E., Amit, R. (1998), Mapping shallow faults at the Evrona playa site using high-resolution reflection method, Geophysics. 15, 1257-1264.

  • Shtivelman, V., Marco, S., Reshef, M., Agnon, A., Hamiel, Y. (2005), Using trapped waves for mapping shallow fault zones, Near Surface Geophysics. 3, 95-101.

  • Sousa-Oliveira, C., Chadi, M., El Foul, D., Izquierdo, A., Martínez-Solares, J.,M., Tadili, B., A. (1997), The Global Seismic Assessment Program (GSHAP), Seismic Hazard Assessment in the Ibero-Maghreb region, On-line report: http://seismo.ethz.ch/gshap/iberomag/report.html.

  • Steeples, D., Near-Surface Seismology. Continuing Education Short Courses (Society of Exploration Geophysicists, Tulsa 1997).

  • Stoffa, P. L. and Fokkema, J. T. and Freire, R. M. and Kessinger, W. P. (1990), Split-step Fourier migration, Geophysics. 55, 410-421.

  • Taner, M. T., Koehler, F., Sheriff, R. E. (1979), Complex seismic trace analysis, Geophysics. 44, 1041-1063.

  • Terrinha, P. A. G. (1998), Structural Geology and Tectonic Evolution of the Algarve Basin, South Portugal, Ph.D. Thesis, Imperial College, London.

  • Terrinha, P., Dias, R. P., Cabral, J. (1998), Neogene and Quaternary evolution of the South Portugal margin, Comunicações do Instituto Geológico e Mineiro. 84, D81-D84.

  • Terrinha, P., Matias, L., Vicente, J., Duarte, J., Luis, J., Pinheiro, L., Lourenco, N., Diez, J., Rosas, F., Magalhaes, V., Valadares, V., Zitellini, N., Roque, C., Mendes Victor, L. and MATESPRO Team (2009), Morphotectonics and strain partitioning at the Iberia-Africa plate boundary from multibeam and seismic reflection data, Marine Geology. 267, 156-174.

  • Treadway, J. A., Steeples, D. W., Miller, R. D. (1988), Shallow seismic study of a fault scarp near Borah Peak, Idaho, Journal of Geophysical Research. 93, 6325-6337.

  • Wang, C.-Y. (2002), The detection of a recent earthquake fault by the shallow reflection seismic method, Geophysics. 67, 1465-1473.

  • Wells, D.L., Coppersmith, K.J. (1994), New empirical relationships among magnitude, rupture length, rupture width, and surface displacements, Bulletin of the Seismological Society of America. 84, 974-1002.

  • Widess, M. B. (1973), How thin is a thin bed, Geophysics. 38, 1176-1180.

  • Williams, R. A., Stephenson, W. J., Odum, J. K., and Worley, D. M. (2001), Seismic reflection imaging of Tertiary faulting and related post-Eocene deformation 20 km north of Memphis, Tennessee, Engineering Geology. 62, 79-90.

  • Yilmaz, Ö. (2001) Seismic Data Analysis (Society of Exploration Geophysicists, Tulsa 2001).

  • Zitellini, N., Gràcia, E., Matias, L., Terrinha, P., Abreu, M.A., De Alteriis, G., Henriet, J.P., Dañobeitia, J. J., Masson, D.G., Mulder, T., Ramella, R., Somoza, L., Diez, S. (2009), The quest for the Africa-Eurasia plate boundary west of the Strait of Gibraltar, Earth and Planetary Science Letters. 280, 13-50.

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Acknowledgments

The authors are particularly grateful to the ANPC (National Authority for Civil Protection Agency) for financing the ERSTA (Study of the Tsunami and Seismic Risk of the Algarve) project. Fernando Santos, from the University of Lisbon is also acknowledged for providing the software for the inversion of the EM data and helpful comments on its application. Our thanks to F. Carrilho and the Instituto de Meteorologia for allowing publication of epicentre location data. The authors would also like to thank G. Manuppella, J. Cabral and P. Terrinha for discussions on the location of the seismic reflection profiles and to L. Martins, the former head of the INETI Geophysics Division for support to this project. We are also indebted to the field crew: J. Leote, F. Caneiras, J. Marquilhas and J. Gomes. The contributions of two anonymous reviewers are also acknowledged.

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  1. Laboratório Nacional de Energia e Geologia, Alfragide, Portugal

    J. Carvalho, E. Ramalho, R. Dias, C. Pinto & R. Ressurreição

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Carvalho, J., Ramalho, E., Dias, R. et al. A Geophysical Study of the Carcavai Fault Zone, Portugal. Pure Appl. Geophys. 169, 183–200 (2012). https://doi.org/10.1007/s00024-011-0318-y

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