Nucleation, linkage and active propagation of a segmented Quaternary normal-dextral fault: the Loma del Viento fault (Campo de Dal铆as, Eastern Betic Cordillera, SE Spain)

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• 作者：Antonio Pedrera^a ; ^{a.pedrera@igme.es} ; Carlos Marí ; n-Lechado^a ; ^{c.marin@igme.es} ; Daniel Stich^b ; ^{daniel@iag.ugr.es} ; Ana Ruiz-Constá ; n^c ; ^{ruiz@gm.univ-montp2.fr} ; Jesú ; s Galindo-Zaldí ; var^d ; ^{jgalindo@ugr.es} ; Carmen Rey-Moral^a ; ^{c.rey@igme.es} ; Flor de Lis Mancilla^b ; ^{florlis@ugr.es}
• 关键词：Faulted hybrid joints ; Active fault segmentation ; Fault linkage ; Seismicity ; Almeria
• 刊名：Tectonophysics
• 出版年：2012
• 期刊代码：82_00401951
• 类别：ear
• 出版时间：5 February, 2012
• 卷：522-523
• 期：Complete
• 页码：208-217
• 文件大小：3898 K

摘要

Active faults from the Campo de Dal铆as (SE Betic Cordillera) allow us to constrain the deformation styles involved in the development of segmented oblique-slip faults. This sector constitutes the widest outcrop of Plio-Quaternary sediments in the northern boundary of the Alboran Sea. It has emerged since the Late Pliocene, and therefore provides recent deformation markers that are not disturbed by erosive processes. The faults started to grow during the Pleistocene, reactivating previous hybrid joints, with a normal-dextral slip. We present a detailed map of the largest fault in the area, the Loma del Viento fault, comprising six onshore segments. Based on field work and aerial photography, the distributions of the contiguous joints have been mapped, and the joints reactivated as faults are identified. Some of these fault segments are hard-linked, and fault slip enhances toward the linkage sectors between them with associated sedimentary depocenters. An electrical tomography profile reveals the wedge geometry of a unit of Pleistocene conglomerates and red silts that were coevally deposited during the fault movement. Long-term slip rate in the central part of the fault is estimated at 0.07 卤 0.03 mm/y. In addition, a seismic crisis nucleated close to the Loma del Viento fault during November 2010 was recorded. Moment tensor analysis of the two mainshocks (Mw 3.5 and 4.2) provides a focal solution indicating a N120掳E striking right-lateral strike-slip fault. The corrugated morphology of the Loma del Viento fault may have influenced its seismic behavior. Some of the fault segments are oblique to the general motion of the fault. These oblique segments would provide higher resistance against the general fault motion and could lock the fault, leading to accumulate elastic energy.