¿Dónde y por qué se producen terremotos en la península Ibérica?

Abstract

The Iberian Peninsula shows low to moderate seismicity caused by active faults that move at rates of the order of 10-2-10-1 mm/y. Maximum potential magnitudes range from 6.0 to 7.0, and the recurrence periods of the major seisms, for each fault, are of the order of 103-104 years. The Betic chains are the most active zone, where the convergence with the African Plate is accommodated by a high number of faults, responsible for several historic earthquakes with intensity = X. The most conspicuous ones are left-lateral, NE-SW strike-slip faults such as Carboneras, Palomares, Alhama and Bajo Segura faults (seisms of Vera, 1526, Torrevieja, 1829, or Lorca, 2011) and E-W extensional faults such as Zafarraya (Arenas del Rey earthquake, 1884). The compression propagated through Iberia from its southern margin also reactivates large strike-slip faults at the Iberian Massif (Manteigas- Vilariça-Bragança –with evidence of Holocene paleoseisms over M = 7.0– and Plasencia). Eastern Iberia undergoes crustal extension linked to the rift at the Valencia trough, which activates normal faults in the Catalonian and Transversal ranges (El Camp and Amer faults, the latter being responsible for Olot seisms, 1427-1428) and the central-eastern Iberian Chain (Concud –with evidences of Late Pleistocene paleoseisms with potential magnitude close to 6.8–, Teruel or Maestrat faults), in this case without recent catastrophic seisms. Active tectonics in the Pyrenees is caused by interaction between rift extension, intraplate compression and isostatic movements. Main seismicity occurs at the north face of the western Pyrenees (Lourdes-Arette) and at the central chain (Vielha earthquake, 1923, in the northern Maladeta fault).