Original paper

Historical earthquakes in the Lower Segura basin (SE Spain): geological and archaeological evidence from pre-roman to modern times

Silva, P.G.; Giner-Robles, J.L.; Elez, J.; Roquero, E.; Rodríguez-Pascua, M.A.; Pérez-López, R.; Martínez-Graña, A.; Bardají, T.; Perucha, M.A.

Zeitschrift für Geomorphologie, Supplementary Issues Volume 62 Supplementary Issue 2 (2019), p. 247 - 269

published: Oct 1, 2019

DOI: 10.1127/zfg_suppl/2018/0492

BibTeX file

ArtNo. ESP023106202008

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Abstract

This paper deals with the analysis of ancient and historical earthquakes in the Lower Segura Depression (SE Spain) at the northern end of the Eastern Betic Cordillera Shear Zone (EBSZ), which is defined within the area by the Lower Segura blind-thrust fault. The work summarizes and updates the existing information on the building and environmental damage dispersed throughout several historical documents, as well as the new historical and archaeological research on the area. The analyses performed consider the evolving paleogeography of the old estuarine zone defined by Ibero-Roman "Sinus ilicitanus" and the ancient prograding delta of the Segura River over the marshes. Topographic data from old descriptions of the zone together with the analysis of the geometry of the medieval irrigation system in the growing delta from pre-Roman to modern (18th century) times, allow the paleogeographic evolution of the zone, until the eventual artificial infilling of the old embayment, to be outlined. Several strong earth- quakes (Intensity ≥ VIII EMS-98) occurred in the area during different historical times. Building damage for the different events was variable depending on the number of settlements (and increasing population) within the ancient embayment. Maximum Intensity X during the most recent earthquake (AD 1829 Torrevieja) mainly occurred over old lands reclaimed in the 18 th century. In addition, dominant earthquake secondary effects (EEEs) were caused by liquefaction processes. This study analyzes the dimensions and distribution of these EEEs for the two main earthquakes in the zone during the years AD 1048 and AD 1829 using the ESI-07 intensity scale. The results draw important inferences on the role of ancient paleo-geography in seismic hazard data from past earthquakes.

Keywords

paleogeography • se spain • paleoseismology • ancient earthquakes • littoral zones