Active faulting in the Betic External Zones (SE, Spain) : the Alcoy Fault Zone
Santamaría-Pérez, Eva (Universitat d'Alacant. Departament de Ciències de la Terra i del Medi Ambient)
Medina-Cascales, Iván (Universitat d'Alacant. Departament de Ciències de la Terra i del Medi Ambient)
Martin-Rojas, Iván (Universitat d'Alacant. Departament de Ciències de la Terra i del Medi Ambient)
Alfaro García, Pedro (Universitat d'Alacant. Departament de Ciències de la Terra i del Medi Ambient)

Date:	2026
Abstract:	Evidence of active faulting is presented from a fault in the eastern Betic External Zones (SE Spain). New fault data are provided for the Alcoy Fault Zone, a structure whose Quaternary activity is currently under debate. This study includes a detailed structural and geomorphic characterization, along with a preliminary palaeoseismological analysis. This fault is ca. 13 km long, and two main sectors are defined based on its surface geometry: a SW sector striking N060E formed by a border fault strand, and a NE sector striking N040E to N065E, formed by a border and an intrabasinal fault strands. The Alcoy Fault Zone displays oblique kinematics, with a predominant left-lateral and a subordinate dip-slip component. Quaternary fault activity is evidenced by a qualitative and quantitative geomorphic analysis, where three geomorphic indices were applied (Smf, Vf, and Bs). The fault presents a marked mountain front with low sinuosity. Cross-fault streams, which are deflected in a left-lateral sense, exhibit knickpoints that coincide with the fault traces and display highly incised valleys. Moreover, the morphology of their watersheds is consistent with an ongoing tectonic uplift in the area. Additionally, the palaeoseismological analysis performed in deformed colluvial deposits suggests a Holocene surface rupture history involving two events during the last ca. 1160 years. The results of this work represent the first step for the seismogenic characterization of the Alcoy Fault Zone and the base for further seismic hazard assessment studies in the External Zones of the eastern Betic Cordillera. However, additional seismicity studies will be required to determine whether the fault is basement-involved or represents a decoupled structure controlled by the Triassic evaporitic layer between the Variscan basement and the pre-Neogene Betic rocks.
Note:	Altres ajuts: VIGROB053 (Universitat d'Alacant), projecte de recerca AICO2021/196 de la Generalitat Valenciana
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Fault characterization ; Active tectonics ; Tectonic geomorphology ; Palaeoseismology ; Betic external zones
Published in:	Geologica acta, Vol. 24 (2026) , p. 1-I (Articles) , ISSN 1696-5728

Adreça original: https://revistes.ub.edu/index.php/GEOACTA/article/view/50864
DOI: 10.1344/GeologicaActa2026.24.4

24 p, 10.5 MB

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