The Betic Cordillera stretches across southern Spain from Gibraltar to Alicante, forming the westernmost arm of the Alpine mountain belt. Its network of faults, including the Alhama de Murcia, Carboneras and Crevillente faults, absorbs the slow convergence between the African and Eurasian plates in the western Mediterranean.
Motion here combines reverse faulting, as the crust is shortened, with strike-slip displacement along northeast-trending fractures. Convergence is slow, only about four to five millimetres per year, so earthquakes are less frequent than in Turkey or Greece, but the faults are shallow and cut through populated valleys.
The Alhama de Murcia Fault produced the deadly 2011 Lorca earthquake (magnitude 5.1), which killed nine people despite its modest size because it was very shallow and close to the town. Historically, the 1884 Andalusian earthquake near Arenas del Rey killed around 800 people and remains the deadliest in modern Spanish history.