Macroseismic Intensity Modelling of Earthquakes in Southern Spain: Attenuation and Tectonic Implications

A modelling of the observed macroseismic intensity of historical and instrumental earthquakes in southern Spain is proposed, with the aim of determining the macroseismic parameters for seismic hazard evaluation in a region in which the characterization of intensity distribution of seismic events shows different levels of difficulty referable to the complex faults system of the area in study. The adopted procedure allows an analytical determination of epicenters and principal attenuation directions of earthquakes with a double level of verification with reference to the maximum shaking area and structural lineaments of the region, respectively. The analyses, carried out on a suitable number of events, highlight, therefore, some elements for a preliminary characterization of a seismic zonation on the basis of the consistency between seismic intensity distribution of earthquakes and corresponding structural framework.

BLANCO, M.J. and SPAKMAN, W. (1993), The P-wave Velocity Structure in the Mantle below the Iberian Peninsula: Evidence for Subducted Lithosphere below Southern Spain, Tectonophysics 221, 13–34.
BOCCALETTI, M., PAPANI, G., GELATI, R., RODRIGUEZ-FERNANDEZ, J., GARRIDO LOPEZ, A.C., and SANZ DE GALDEANO, C. (1987), Neogene-Quaternary Sedimentary-tectonic Evolution of the Betic Cordillera, Acta Naturalia de l’Ateneo Parmense 23, 179–200.
BOTTARI, A., FEDERICO, B., and LO GIUDICE, E. (1984), The Correlation between the Macroseismic Attenuation Trend and the Geostructural Framework: The Calabro-Peloritanian Arc as an Example, Tectonophysics 108, 33–49.
GALINDO-ZALDI´VAR, J., JABALOY, A., SERRANO, I., MORALES, J., GONZA´ LEZ-LODEIRO, F. and TORCAL, F. (1999), Recent and Present-day Stresses in the Granada Basin (Betic Cordilleras): Example of a Late Miocene-present-day Extensional Basin in a Convergent Plate Boundary, Tectonics 18, 686–702.
GONZA´ LEZ-LODEIRO, F., ALDAYA, F., GALINDO-ZALDIVAR, J., and JABALOY, A. (1996), Superposition of Extensional Detachments during the Neogene in the Internal Zones of the Betic Cordilleras, Geol. Rundschare 85, 350–362.
IBAN˜ EZ, J.M, BOTTARI, C, ESQUIVEL, J.A, MORALES, J., and ALGUACIL, G. (1999), Magnitude-intensity Relations for Instrumental and Historical (IX-XIX Century) Earthquakes in South Spain. Tectonical and Seismic Hazard Implications, Bull. Seismol. Soc. Am., still in preparation.
LONERGAN, L. and WHITE, N., (1997), Origin of the Betic-Rift Mountain Belt, Tectonic 16, 504–522.
LOPEZ-CASADO, C.,MOLINA-PALACIOS, S., DELGRADO J., and PELAEZ, J.A. (1999), Attenuation of Intensity with Epicentral Distance in the Iberian Penisula, still in preparation
MEZCUA, J. (1982), Catalogo general de isosistas de la Penisula Iberica, Publicacio` n 202 IGN, Madrid.
MORALES, J., SERRANO, I., JABALOY, A., GALINDO-ZALDIVAR, J., ZHAO, D., TORCAL, F., VIDAL, F., and GONZA´ LEZ-LODEIRO, F. (1999), Active Continental Subduction beneath the Betic Cordillera and the Albora´n Sea, Geology 27, 735–738.
SANCHEZ NAVARRO NEUMAN, M. (1921), Lista de terremotos mas notables sentidos en la Penisula Iberica (a.C. 1917), Est. Sism. De Cartuja, 11–65.
SANZ dE GALDEANO, C., LOPEZ CASADO, C., DELGADO, J., and PEINADO, M.A. (1995), Shallow Seismicity and Active Faults in the Betic Cordillera. A Preliminary Approach to Seismic Sources Associated with Specific Faults, Tectonophysics 248, 293–302.
SEBER, D., BARAZANGI, M., IBERBRAHIM, A., and DEMNATI (1996), Geophysical Evidence for Lithospheric Delamination beneath the Albora´n Sea and Rif-Betic Mountains, Nature 379, 785–790.
TERAMO, A., STILLITANI, E., and BOTTARI, A. (1995a), Anisotropic Characterization of Macroseismic Fields, Natural Hazard 11, 223–245.
TERAMO, A., STILLITANI, E., and BOTTARI, A. (1995b), An Anisotropic Attenuation Law of the Macroseismic Intensity, Natural Hazard 11, 203–221.
TERAMO, A., TERMINI, D., STILLITANI, E., and BOTTARI, A. (1996), The Determination of Epicentre by a Vectorial Modelling of Macroseismic Intensity Distribution, Natural Hazard 13, 101–117.
TERMINI, D., BOTTARI, A., TERAMO, A., and TUVE` , T. (2005a), On the Observed Intensity Filtering in the Anisotropic Distribution Modelling of Macroseismic Intensity. Pure and Appl. Geophys. 162, 683–697
TERMINI, D., TERAMO, A., BOTTARI, C., and TUVE` , T. (2005b) An Anisotropic Attenuation Law of Macroseismic Intensity Performed on Virtual Intensity Distribution of Seismogenic Zones. Pure Appl. Geophys. 162, 707–714.
TERMINI, D., BOTTARI, A., TERAMO, A., and BOTTARI, C. (2005c), On the Intensity Virtual Area Characterization in the Intensity Distribution Modelling by Macroseismic Planes, Pure Appl. Geophys. 162, 699–705.
VISSERS, R.L.M., PLATT, J.P., and VAN DER WALD. (1995), Late Orogenic Extension of the Betic Cordillera and the Alboran domain: A Lithospheric View, Tectonics 14, 786–803.
WEIJERMARS, R. (1985), Uplift and Subsidence History of the Alboran Basin and a Profile of the Alboran Diapir (W-Mediterranean), Geol. Mijnbouw 64, 349–356.