Archaeoseismological Analysis of a Late Bronze Age Site on the Alhama de Murcia Fault, SE Spain

Abstract

An archaeoseismological study of Tira del Lienzo (Totana, Spain) was undertaken. The site belongs to the Argar archaeological group (2200-1550 cal. B.C.; Bronze Age). It is located on the trace of the reverse left-lateral Alhama de Murcia fault (AMF) that was responsible for the 5.1 Mw 2011 Lorca earthquake. The constructive typology of the site consists of mortar-free irregular natural boulders (dry-set masonry) and differs from earlier archaeoseismological sites built on regular masonry constructions in the Betic Cordillera. Four Earthquake Archaeological Effects (EAEs) were identified as follows: (1) an apparent surface rupture (c. 18 cm left-lateral offset), (2) the differential coseismic uplift of several centimeters affecting the main building of the settlement, (3) the widespread development of fractures on the ground surface (ground cracks) in a NE-SW direction consistent with the kinematics of the AMF, and (4) fractures in boulders that constitute the remains of the dry stone walls at the site. Structural analysis of the two fracture types reveals two nearly orthogonal sets (NE-SW and NW-SE), matching the strike-slip kinematics of the AMF in the zone. Archaeoseismic evidence and related radiocarbon dates of the different building phases of the Bronze Age site indicate the probable occurrence of at least one strong seismic event (6.3-6.5 Mw; IX ESI-07) around 1550 cal. B.C., or soon after, triggering the destruction and probably the eventual abandonment of the site. We have identified an ancient lost earthquake from the Bronze Age and report the first archaeoseismological evidence of surface rupture in the Iberian Peninsula. This study also provides the first numerical data in the Totana-Alhama segment of the AMF based on the recorded archaeoseismic displacements. These data allowed us to characterize the related slip rates (0.05 mm/yr) to define the seismic potential of the analyzed fault segment of the AMF, which was poorly defined by previous seismic and geological data. C 2015 Wiley Periodicals, Inc.

A 3D measurement of the offset in paleoseismological studies

“…As expected after the offset calculation, the lateral component of the fault was much higher than the vertical one. The obtained net slip rate was much larger than proposed to date using different approaches (Martínez-Díaz, 1998;Martínez-Díaz et al, 2003;Masana et al, 2004;Ortuño et al, 2012;Echeverria et al, 2013;Ferrater et al, 2015b).…”

“…A number of studies have focused on calculating the seismic parameters of the AMF (Silva et al, 1997;Martínez-Díaz, 1998;Martínez-Díaz et al, 2003;Masana et al, 2004;Ortuño et al, 2012;Echeverria et al, 2013;Ferrater et al, 2015b;Ferrater et al, submitted). Several attempts to estimate the slip rate of the AMF have been done.…”

Catalogue of the Geological Effects of Earthquakes in Spain Based on the ESI-07 Macroseismic Scale: A New Database for Seismic Hazard Analysis

“…The catalogue also considers geological information for ancient earthquakes only documented in archaeological sites, differentiating several types of earthquake archeological effects (EAEs) of the classification [13]. Among the most ancient events included in the catalogue are those of the Cueva del Toro in Antequera (Málaga) of Neolithic age (c. 3700 BCE) [14] and the Bronze Age event of La Tira del Lienzo in Totana, Murcia (c. 1550 BCE) [15]. A surface rupture affecting dry masonry walls along the well-known Lorca-Alhama de Murcia left-lateral fault in the Eastern Betic Cordillera documents this Bronze Age earthquake.…”

Los terremotos antiguos del conjunto arqueológico romano de <em>Baelo Claudia</em> (Cádiz, Sur de España): Quince años de investigación arqueosismológica

“…Los yacimientos arqueológicos pueden utilizarse como antiguos sismógrafos ("seismoscopios") que potencialmente pueden registrar lo que científicamente se denominan " terremotos antiguos" (Sintubin et al, 2010), esto es " terremotos perdidos" tan solo documentados por datos arqueológicos. En España existen diversos ejemplos de análisis arqueosismológicos, los más recientemente documentados en Complutum (Alcalá de Henares; Rodríguez-Pascua et al, 2014;2016), y en el yacimiento del Bronce de La Tira del Lienzo (Totana; Ferrater et al, 2015).…”