Advertisement

Journal of Seismology

, Volume 20, Issue 4, pp 1075–1088 | Cite as

Source mechanism studies of earthquakes in the Ibero-Maghrebian region and their tectonic implications

  • E. Buforn
  • A. Udías
  • C. Pro
Original Article

Abstract

Seismicity of the Ibero-Maghrebian region includes the occurrence of shallow, intermediate depth, and very deep earthquakes. This is a very rare occurrence for a region not associated to an active subduction zone. Detailed studies of the source mechanism of these three types of earthquakes have been made possible through the collaboration with Prof. Madariaga. They give important information about the complex tectonic of the region. Shallow earthquakes at the west and east ends of the region have predominant reverse faulting with NW-SE trending horizontal pressure axes. The center part is the most tectonically complex. At the Strait of Gibraltar, there is a change on focal mechanisms from reverse faulting to strike-slip motion in northern Morocco, conserving the horizontal compression on NW-SE direction. In the Alboran Sea, mechanisms are of normal faulting with E-W trending horizontal tension axes, and in south Spain, mechanisms are of mixed solutions. The intermediate depth earthquakes (40–130 km) are located at both sides of the Strait of Gibraltar, at the western part distributed in E-W direction. The most important concentration, however, is located at the east of Gibraltar in a N-S trending thin vertical body and has different mechanisms. The very deep earthquakes (650 km) are concentrated at a small volume, and their mechanism corresponds to N-S vertical planes or horizontal ones. A tectonic model for the region is presented to explain the shallow, intermediate, and deep earthquakes.

Keywords

Ibero-Maghrebian region Source mechanism Seismic slip distribution Tectonic model 

Notes

Acknowledgments

The authors want to thanks Dr. S. Cesca (GFZ, Potsdam) who provided Fig. 7, Prof. M. Bezzeghoud (University of Evora, Portugal), Dr. J. M. Martínez Solares (IGN, Madrid) for the helpful discussion, and the referees for their comments which have improved the quality of manuscript. This work has been partially supported by MINECO, project CGL2013-45724-C3-R-1, by the INNOCAMPUS project (Ministerio de Economía y Competitividad, Orden CIN/1934/2010) and by Programa de Financiación UCM-Santander Ayuda a Grupos de InvestigaciónValidados GR3/14).

References

  1. Bezzeghoud M, Buforn E (1999) Source parameters of the 1992 Melilla (Spain, Mw = 4.8), 1994 Alhoceima (Morocco, Mw = 5.8) and 1994 Mascara (Algeria, Mw = 5.7) earthquakes and seismotectonic implications. Bull Seismol Soc Am 89:359–372Google Scholar
  2. Bezzeghoud M, Dimitro D, Ruegg JC, Lammali K (1995) Faulting mechanism of the El Asnam (Algeria) 1954 and 1980 earthquakes from modelling of vertical movements. Tectonophysics 249:249–266CrossRefGoogle Scholar
  3. Blanco MJ, Spakman W (1993) The P-wave velocity structure of the mantle below the Iberian peninsula: evidence for subducted lithosphere below southern Spain. Tectonophysics 221:13–34CrossRefGoogle Scholar
  4. Borges JF, Fitas A, Bezzeghoud M, Teves-Costa P (2001) Seismotectonics of Portugal and its adjacent area. Tectonophysics 337:373–387CrossRefGoogle Scholar
  5. Buforn E (2008) Seismotectonics of Azores-Tunisia. In: Mendes-Victor L, Oliveira CS, Azevedo J, Ribeiro A (eds) The 1755 Lisbon earthquake: revisited. Springer, New York, pp 397–410Google Scholar
  6. Buforn E, Udías A (2010) Azores-Tunisia, a tectonically complex plate boundary. Advances in Geophysics. 52, 3, DOI:  10.1016/S0065-2687(10)52003-X. 1139–1182
  7. Buforn E, Udías A, Colombás M (1988) Seismicity, source mechanism and tectonics of the Azores-Gibraltar plate boundary. Tectonophysics 152:89–118CrossRefGoogle Scholar
  8. Buforn E, Udías A, Madariaga R (1991) Intermediate and deep earthquakes in Spain. Pure Appl Geophys 136:375–393CrossRefGoogle Scholar
  9. Buforn E, Sanz de Galdeano C, Udías A (1995) Seismotectonics of the Ibero-Maghrebian region. Tectonophysics 248:247–261CrossRefGoogle Scholar
  10. Buforn E, Coca P, Udías A, Lasa C (1997) Source mechanism of intermediate and deep earthquakes in Southern Spain. J Seismol 1:113–130CrossRefGoogle Scholar
  11. Buforn E, Bezzeghoud M, Udías A, Pro C (2004) Seismic sources on the Iberia-African plate boundary and their tectonic implications. Pure Appl Geophys 161:623–646. doi: 10.1007/s00024-003-2466-1 CrossRefGoogle Scholar
  12. Buforn E, Benito B, Sanz de Galdeano C, del Fresno C, Muñoz D, Rodríguez I (2005) Study of the damaging earthquakes of 1911, 1999 and 2002 in the Murcia (Spain) region: seismotectonics and seismic risk implications. Bull Seismol Soc Am 95:549–567CrossRefGoogle Scholar
  13. Buforn E, Pro C, Cesca S, Udías A, del Fresno C (2011) The 2010 Granada, Spain deep earthquake. Bull Seismol Soc Am 101:2418–2430. doi: 10.1785/0120110022 CrossRefGoogle Scholar
  14. Buforn E, Udías A, Pro C (2015) Large earthquakes at the Ibero-Maghrebian region: basis for an EEWS. Pure Appl Geophys 172:2387–2396. doi: 10.1007/s00024-014-0954-0 CrossRefGoogle Scholar
  15. Cesca S (2005) Inversión del tensor momento sísmico de terremotos superficiales a distancias regionales. PhD Thesis, Universidad Complutense de Madrid, Spain, 289 ppGoogle Scholar
  16. Cesca S, Heimann S, Stammler K, Dahm T (2010) Automated procedure for point and kinematic source inversion at regional distances. J Geophys Res 115:B06304. doi: 10.1029/2009JB006450 CrossRefGoogle Scholar
  17. Cesca S, Rohr A, Dahm T (2013) Discrimination of induced seismicity by full moment tensor inversion and decomposition. J Seismol 17(1):147–163. doi: 10.1007/s10950-012-9305-8 CrossRefGoogle Scholar
  18. Chung W, Kanamori H (1976) Source process and tectonic implications of the Spanish deep-focus earthquake of March 29, 1954. Phys Earth Planet Inter 13:85–96CrossRefGoogle Scholar
  19. CMT (2015) Global centroid moment tensor catalog. http://www.globalcmt.org/
  20. Coca P, Buforn E (1994) Mecanismos focales en el sur de España: periodo 1965–1985. Estud Geol 50:33–45CrossRefGoogle Scholar
  21. de Lis Mancilla F, Stich D, Berrocoso M, Martín R, Morales J, Fernandez-Ros A, Páez R, Pérez-Peña A (2013) Delamination in the Betic range: deep structure, seismicity, and GPS motion. Geology 41(3):307–310CrossRefGoogle Scholar
  22. De Louis B, Vallée M, Meghraoui M, Calais E, Maouche S, Lamalli K, Mahsas A, Briole P, Benhamouda F, Yelles A (2004) Slip distribution of the 2003 Boumerdes-Zemmouri earthquake, Algeria, from teleseismic, GPS, and coastal uplift data. Geophys Res Lett 31:L18607. doi: 10.1029/2004GL020687 CrossRefGoogle Scholar
  23. Deschamps A, Lyon-Caen H, Madariaga R (1980) Mise au point sur les méthodes de calcul de sismogrammes synthetiques de longue période. Ann Geophys 36:167–178Google Scholar
  24. Grimison NL, Chen WP (1986) The Azores-Gibraltar plate boundary: focal mechanism, depths of earthquakes and their tectonic implications. J Geophys Res 91:2029–2047CrossRefGoogle Scholar
  25. Hatzfeld D (1978) Etude sismotectonique de la zone de collision Ibero-Maghrébine. Ph.D. Thesis, Université de Grenoble (France), 281 ppGoogle Scholar
  26. Heimann S (2011) A Robust Method to estimate kinematic earthquake source parameters. PhD. Thesis, University of Hamburg, (Germany)Google Scholar
  27. IGN (2015) Instituto Geográfico Nacional. http://www.ign.es
  28. Kikuchi A, Kanamori H (1991) Inversion of complex waves III. Bull Seismol Soc Am 81:2335–2350Google Scholar
  29. Levander A, Bezada MJ, Niu F, Humphreys ED, Palomeras I, Thurner SM, Masy J, Schmitz M, Gallart J, Carbonell R, Miller MS (2014) Subduction-driven recycling of continental margin lithosphere. Nature 515:253–256. doi: 10.1038/nature13878 CrossRefGoogle Scholar
  30. López Arroyo A, Udías A (1972) Aftershocks sequence and focal parameters of the Feb. 28, 1969 earthquake of the Azores-Gibraltar fracture zone. Bull Seismol Soc Am 62:699–719Google Scholar
  31. Malgrange M, Madariaga R (1983) Complex distribution of large thrust and normal fault earthquakes in the Chilean subduction zone. Geophys J R Astron Soc 73:489–506CrossRefGoogle Scholar
  32. Martínez-Solares JM, López Arroyo A (2004) The great historical 1755 earthquake. Effects and damage in Spain. J Seismol 8:275–294CrossRefGoogle Scholar
  33. Mézcua J, Rueda J (1997) Seismological evidence for a delamination process in the lithosphere under Alborán Sea. Geophys J Int 129:F1–F8CrossRefGoogle Scholar
  34. Pazos A, Buforn E, Martín Davila J, Udías A, Hanka W, Strollo A, Mattesini M, Benzzeghoud M, Harnafi M, Cibeira A, Cabieces R, Prian J, Quijano J, Crespillo S, Caldeira B, El Ouai D, ROA Seismic Group (2015) The seismic broadband Western Mediterranean network and other instrumentation in the Western Mediterranean region. 26th general assembly of the international union of geodesy and geophysics, Prague (Czech Rep.) 22 June-2 July 2015Google Scholar
  35. Pro C, Buforn E, Bezzeghoud M, Udías A (2013) The earthquakes of 29 July 2003, 12 February 2007 and 17 December 2009 in the region of Cape Saint Vincent (SW Iberia) and their relation with the 1755 Lisbon earthquake. Tectonophysics 583:16–27CrossRefGoogle Scholar
  36. Pro C, Buforn E, Cesca S, Sanz de Galdeano C, Udías A (2014) Rupture process of the Lorca (southeast Spain) 11 May 2011 (Mw = 5.1) earthquake. J Seismol 18:481–495. doi: 10.1007/s10950-014-9421-8 Google Scholar
  37. Udías A (1967) The focal mechanism of earthquakes in the southern coast of the Iberian Peninsula. Tectonophysics 4:229–234CrossRefGoogle Scholar
  38. Udías A, López-Arroyo A (1970) Body and surface wave study of the source parameters of the March 15, 1964, Spanish earthquake. Tectonophysics 9:323–346CrossRefGoogle Scholar
  39. Udías A, Muñoz D (1979) The Andalusian earthquake of 25 December 1884. Tectonophysics 53:291–299CrossRefGoogle Scholar
  40. Udías A, López-Arroyo A, Mezcua J (1976) Seismotectonics of the Azores-Alboran region. Tectonophysics 31:259–289CrossRefGoogle Scholar
  41. Udías A, Muñoz D, Buforn E, Sanz de Galdeano C, del Fresno C, Rodríguez I (2005) Reevaluation of the earthquakes of 10 March and 19 May 1951 in southern Spain. J Seismol 9:99–110CrossRefGoogle Scholar
  42. Yelles K, Djellit H, Beldjoudi H, Bezzeghoud M, Buforn E (2004) The AinTemouchent (Algeria) earthquake of December 22nd, 1999. Pure Appl Geophys 161:607–621CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2016

Authors and Affiliations

  1. 1.Departamento de Geofísica y Meteorología/Universidad ComplutenseMadridSpain
  2. 2.IGEO, UCM-CSICMadridSpain
  3. 3.Departamento de Física/Universidad de ExtremaduraMéridaSpain

Personalised recommendations