Seismic palaeogeography of coastal zones in the Iberian Peninsula: Understanding ancient and historic earthquakes in Spain.

Abstract

Roman city of Baelo Claudia located in the Bolonia Bay (Strait of Gibraltar); and the effects of the earthquake of AD 1048on the ancient Sinus Ilicitanus (Bajo Segura Depression) during Muslim times. Descriptions from Roman and Arabic geographers are cross-checked with existing palaeogeographic models based on geological data. This type of analysis results in ancient macroseismic scenarios for the interpretation of theoretical distributions of intensities and environmental effects supporting the concept of "seismic palaeogeography" proposed in this paper.Keywords: Palaeoseismology, Archaeosismology, Palaeogeography, ancient earthquake, littoral zone, South Spain. ResumenEl presente trabajo recoge tres ejemplos de terremotos antiguos (218 AC, 40-60 AD y 1048 AD) ocurridos en zonas litorales del S y SO de la Península Ibérica con la intención de ilustrar el uso de datos geológicos y arqueológicos en la caracterización macrosísmica de los mismos. En la mayor parte de los sísmos ocurridos con anterioridad al siglo X d.C. la información documental histórica que se posee es muy escasa o inexistente. El presente trabajo muestra que el actual estado de conocimiento en paleosismología y arqueosismologia sobre este tipo de terremotos sobrepasa con creces la información documental histórica, permitiendo la multiplicación de los puntos de información macrosísmica mediante el uso de la escala ESI-07 (Environmental Seismic Intensity). Consecuentemente, el análisis geológico de los terremotos antiguos mejora su conocimiento y análisis paramétrico, permitiendo avanzar la evaluación de la peligrosidad sísmica de las zonas afectadas. El aspecto que se pone de especial relieve en este trabajo es el análisis de la paleogeografía existente en la antigüedad, ya que todas las zonas (afectadas) analizadas en este trabajo corresponden a zonas estuarinas abiertas que se han ido rellenado por aportes fluviales o de forma artificial con el tiempo. Se analizan los efectos del terremoto de 218 AC en las zonas estuarinas del Golfo de Cádiz y muy especialmente en el antiguo Lacus Ligustinus (marismas del Guadalquivir) durante época romana; los efectos del terremoto de 40-60 AD en la antigua Bahía de Baelo Claudia (Estrecho de Gibraltar); y los efectos del terremoto de 1048 AD en el antiguo Sinus ilicitanus (Depresión del Bajo Segura) durante época musulmana. Se han cotejado descripciones de geógrafos romanos y árabes con modelos basados en datos geológicos. Este tipo de análisis ha permitido generar antiguos escenarios macrosísmicos basados en la paleogeografía y reinterpretar las distribuciones teóricas de intensidades y los efectos ambientales de los terremotos estudiados que es a lo que se refiere el concepto de "paleogeografía sísmica" propuesto en este trabajo.

Palaeoseismic crisis in the Galera Fault (S Spain). Consequences in Bronze Age settlements?

“…More recently, during instrumental times, the GF was the seismogenic source of the 1964 Galera Earthquake (I= VIII, 4.7 mbLg, (Martínez-Solares & Mezcua, 2002). This earthquake was responsible for severe damage to many buildings in Galera, Orce, Huéscar, and Castilléjar villages (Silva Barroso et al, 2014), for partially reactivating a massive rock avalanche close to Galera village, and for causing a great social alarm. The GF has also been proposed as the seismogenic source of the 1973 Huéscar Earthquake (4.0 mbLg) and the background seismicity in the area.…”

“…Seismicity in the Central Betic Cordillera includes the most destructive onshore historical earthquake in Spain, the 1884 Andalusian Earthquake (IEMS98 IX-X/estimated magnitude Mw=6.5) (Muñoz & Udías, 1991), and other significant events such as the 1531 Baza earthquake (IMMI VIII-IX; estimated magnitude of ca. 6.0) (Sanz de Galdeano et al, 2012;Martínez-Solares & Mezcua, 2002), the 1964 SW Galera earthquake (mbLg 4.8, VIII) (Martínez-Solares & Mezcua, 2002;García-Tortosa et al, 2007;Silva Barroso et al, 2014) or the 2021 Granada seismic sequence (Lozano et al, 2022;Madarieta-Txurruka et al, 2021b;Madarieta-Txurruka et al, 2022). Moreover, the central sector of the Betic Cordillera has been densely populated since prehistoric times, and today includes important urban centres such as Granada, Guadix, and Baza.…”

Comparative Analysis and Evaluation of Seismic Response in Structures: Perspectives from Non-Linear Dynamic Analysis to Pushover Analysis

“…First and foremost, it is crucial to understand the seismic context in which the analysed structures are located. This region is characterised by significant seismic activity due to its location in a high seismic risk zone [1]. Seismic zones, such as the one covering the study area, are subject to tectonic movements that can have devastating effects on buildings if proper design and construction measures to withstand them are not taken [2].…”

3D Modelling of Archaeoseismic Damage in the Roman Site of Baelo Claudia (Gibraltar Arc, South Spain)

“…The Roman city of Baelo Claudia is one of the most renowned archaeoseismological sites in the Mediterranean, since its present remains preserve the impact of two different earthquakes during Roman times (first and fourth centuries CE; [9]) and the subsequent tsunami destruction that followed the last event [10,11]. The site has been the subject of deep archaeoseismological analyses, including geoarchaeological research, 2D GPR and ERT geophysical prospections [12][13][14][15], and 2D detailed mapping of damage [14,16], as well as complementary geological and paleogeographical analyses [11,12,14,17]. To date, all the compiled 2D information has followed the archaeoseismological classification and routines proposed by Rodríguez-Pascua et al [18], presently synthetized and updated in the Springer Encyclopedia on Cultural Heritage [19,20].…”