Active faulting in the central Betic Cordillera (Spain): Palaeoseismological constraint of the surface-rupturing history of the Baza Fault (Central Betic Cordillera, Iberian Peninsula)

This paper on the Baza Fault provides the first palaeoseismic data from trenches in the central sector of the Betic Cordillera (S Spain), one of the most tectonically active areas of the Iberian Peninsula. With the palaeoseismological data we constructed time-stratigraphic OxCal models that yield probability density functions (PDFs) of individual palaeoseismic event timing. We analysed PDF overlap to quantitatively correlate the walls and site events into a single earthquake chronology. We assembled a surface-rupturing history of the Baza Fault for the last ca. 45,000 years. We postulated six alternative surface rupturing histories including 8–9 fault-wide earthquakes. We calculated fault-wide earthquake recurrence intervals using Monte Carlo. This analysis yielded a 4750–5150 yr recurrence interval. Finally, compared our results with the results from empirical relationships. Our results will provide a basis for future analyses of more of other active normal faults in this region. Moreover, our results will be essential for improving earthquake-probability assessments in Spain, where palaeoseismic data are scarce.This research was founded by the Spanish Ministry of Economics, Industry and Competitiveness (MINECO) research Projects CGL2011-30153-C02-02 and EPILATES (CGL2015-65602-R). Also by the research group VIGROB053 (University of Alicante), the research Project UJA2014/06/17 (Caja Rural de Jaén and University of Jaen) and the research contract 2015CL015 (University of Jaen)

Characterization of the shallow subsurface structure across the Carrascoy Fault System (SE Iberian Peninsula) using P-wave tomography and Multichannel Analysis of Surface Waves

Acknowledgement. The authors would like to acknowledge the project INTERGEO (CGL2013-47412-C2-1-P) GEO3BCNCSIC for the data access. Data are public access through SeisDARE (DeFelipe et al., 2021), dataset Martí et al.(2015). The Ministry of Education and Culture of the Republic of Indonesia is thanked for the main author's Ph.D. scholarship (D3.2/KD.02.01/2019). JA is funded by MICINN (IJC2018-026335-I). I.P. is funded by the Spanish Government and the Universidad de Salamanca (Beatriz Galindo grant BEGAL 18/00090). IDF is funded by a FEDER-Junta de Castilla y León Postdoctoral contract (SA0084P20). We thank the GIPP-GFZ, (Germany) and Lisbon University (Portugal) for the instrumentation provided. Generalitat de Catalunya (AGAUR) grant 2017SGR1022 (GREG); EU (H2020) 871121 (EPOSSP); and EIT-RawMaterias 17024 (SIT4ME). We sincerely thank Seismic Unix CWP (Center for the Wave Phenomena, Colorado School of Mines (Cohen and Stockwell, 2019)). We also thank all the people involved directly or indirectly in this work.The seismicity in the SE Iberian Peninsula is distributed parallel to the coast in a well-developed strike-slip fracture system known as the Eastern Betic Shear Zone (EBSZ). This work focuses on the characterization of the shallow subsurface structure of the Algezares-Casas Nuevas Fault, within the Carrascoy Fault System of the EBSZ. The Carrascoy Fault borders the Guadalentín Depression to the south, which is a densely populated area with extensive agricultural activity. Therefore, this faults system represents a seismic hazard with significant social and economic implications. We have constructed two velocity-depth models based on P-wave tomography and Multichannel Analysis of Surface Waves (MASW) acquired from seismic reflection data. The resulting velocity models have allowed us to interpret the first ~250m depth and have revealed: i) the thickness of the critical zone; ii) the geometry of the Algezares-Casas Nuevas Fault; iii) the depth of the Messinian/Tortonian contact and iv) the presence of blind thrusts and damage zones under the Guadalentín Depression. Our results have also helped us to estimate an apparent vertical slip rate of 0.66±0.06m/ky for the Algezares-Casas Nuevas Fault since 209.1±6.2ka. Our results provide a methodological and backflow protocol to study the shallow subsurface of active faults, complementing previous geological models based on paleoseismological trenches, and can be used to improve the seismic hazard assessment of tectonically active regions around the world

Dataset: Improved geological slip rate estimations in the complex Alhama de Murcia Fault zone (SE Iberia) and its implications for fault behavior

This repository contains datasets used for the article "Improved geological slip rate estimations in the complex Alhama de Murcia Fault zone (SE Iberia) and its implications for fault behaviour" published in Tectonics. The dataset includes two zip files: A. Uninterpreted_trenches: This folder contains PDF files with uninterpreted photologs of all the trenches carried out in the paleoseismic survey of the study. Each file contains all the trenches from a paleoseismic site, as named in the paper. B. MATLAB_codes: This folder contains MATLAB codes to compute the probability density functions of the slip rates, based on fault slips and numerical dates obtained in the trenches. These codes are intented to be run using the code by Zechar and Frankel (2009) and are written based on the format designed by these authors. A separate code for each trench and slip component is provided. To read and edit these files use MATLAB or an open source code editor such as Spyder. The data from this article is part of the doctoral thesis of Octavi Gómez-Novell developed at the University of Barcelona. You can findn it publicly available at: http://hdl.handle.net/2445/183755 *For any further requests or suggestions, please write to the corresponding author of the publication, Octavi Gómez-Novell ([email protected]). </p

Active Faults in Iberia

43 pages, 9 figures, 1 tableThe distribution of active faults in the Iberian Peninsula is not homogeneous, being mainly present, but not only, in areas affected by the Alpine Orogeny. They are located in several regions: (1) The Iberian Massif, including Portugal, and Galicia and Cantabrian Mountains in the North, (2) The Pyrenees, (3) The NE of Iberia, (4) The Iberian Cordillera, and (5) The Betic Cordillera. The Pyrenees, the Iberian Cordillera, and particularly the Betic Cordillera are the most active regions. These faults have being considered active in a broad sense, that is to say, corresponding to faults that, at least, present movements during the Quaternary, not restricting them only to those presenting displacements during the late 10,000 years. Although important, faults situated offshore have not being included in the present reviewPeer Reviewe