Growth geometries in the Bajo Segura Fault Zone (Eastern Betic Cordillera)

En este trabajo presentamos el análisis de una serie de secuencias de crecimiento asociadas a los pliegues de propagación de la Zona de Falla del Bajo Segura (Cordillera Bética oriental). Los nuevos datos de campo aportados permiten estimar la edad de inicio de la deformación durante el Mioceno superior (~ 6,5 Ma) en el frente meridional de pliegues; mientras que en el frente septentrional comenzó durante el Plioceno basal (~ 5,3 Ma). De acuerdo con estos nuevos datos, proponemos una tasa de desplazamiento del frente septentrional de 0,09 mm/año, algo más baja que las propuestas con anterioridad. También se discuten las implicaciones que tienen estos datos en las hipótesis de evolución estructural de la Zona de Falla del Bajo SeguraWe present here the analysis of growth geometries related to the fault propagation folds of the Bajo Segura Fault Zone, in the Eastern Betic Cordillera (Spain). New detailed field data permit us to establish the beginning of the deformation in the southern front of the folds during the Upper Miocene (~ 6.5 Ma) and in the northern front during the lowermost Pliocene (~ 5.3 Ma). According to these new data, we propose a slip rate for the north front of folds of 0.09 mm/year, i.e. slightly lower than previously proposed. Moreover, we discuss the implications for the structural evolution hypothesis proposed for the Bajo Segura Fault Zon

Calculation of Seismic Damage Scenarios in Valencian Community using Model Builder

En este trabajo presentamos una herramienta que permite simular de forma rápida Escenarios de Daño Sísmico (EDS) a partir de cualquier terremoto que se produzca dentro de la Comunidad Valenciana. Para su diseño se ha empleado la aplicación Model Builder de ArcGIS. Los datos de entrada necesarios para la simulación son: el terremoto, la cartografía litológica, los municipios con el censo de edificios, unas matrices de probabilidad de daño y el censo de población por municipios. Mediante el uso de leyes de atenuación de ondas sísmicas y teniendo en cuenta el efecto de sitio se calcula la sacudida sufrida en términos de intensidad sísmica (EMS-98). Posteriormente se obtienen los daños sufridos por los edificios (leves, moderados y graves) mediante la aplicación de matrices de probabilidad de daño. Finalmente se calculan los daños a la población (heridos leves, heridos graves, muertos y personas sin hogar) utilizando la metodología ATC-13 propuesta por el ATC (Consejo de Tecnología Aplicada) de California. Los resultados obtenidos se representan en varios mapas. De esta forma se ha implementado una herramienta de gran utilidad para estudios orientados a la planificación municipal ante el riesgo sísmico, como pueden ser los Planes de Actuación de Protección Civil.In this paper we present a tool which allows a quick simulation of Seismic Damage Scenarios (SDS) from any earthquake occurred within Valencian Community. For its design we have used ArcGIS Model Builder application. The input data required for the simulation are: the earthquake, the lithological cartography, municipalities with their building census, a damage probability matrices and the municipalities’ population census. Using seismic wave attenuation laws and considering the local effect, the tool calculates the seismic shaking expressed in seismic intensity (EMS-98). Then, with the Vulnerability Index Method (VIM) it obtains building damages (mild, moderated and serious) through the application of damage probability matrices. Finally, population damages (people with minor or serious injuries, deads and homeless) are calculated using the ATC-13 method proposed by the ATC (Applied Technology Council). Obtained results are represented in several maps. In this way we have implemented a useful tool in studies of municipal planning for facing seismic risk, like Protección Civil Actuation Plans.Este trabajo ha sido financiado por el proyecto de investigación del MINECO CGL2011-30153-C02-02, el grupo de investigación de la U. de Alicante VIGROB053, el contrato de investigación de la U. de Jaén 2015CL015, el proyecto de investigación de la U. de Jaén UJA2014/06/17 y una Ayuda de Máster e Iniciación a la Investigación concedida por el Programa Propio del Vicerrectorado de Investigación, Desarrollo e Innovación para el fomento de la I+D+i en la U. de Alicante

Geometry and kinematics of the Baza Fault (central Betic Cordillera, South Spain): insights into its seismic potential

The geometry and kinematics of active faults have a significant impact on their seismic potential. In this work, a structural characterization of the active Baza Fault (central Betic Cordillera, southern Spain) combining surface and subsurface data is presented. Two sectors are defined based on their surface geometry: a northern sector striking N–S to NNW–SSE with a narrow damage zone and a southern sector striking NW–SE with a wide damage zone. A kinematic analysis shows pure normal fault kinematics along most of the fault. Geometric differences between the northern and southern sectors are caused by i) a heterogeneous basement controlling the fault geometry at depth and in the cover; ii) different orientations of the Baza Fault in the basement with respect to the regional extension direction and iii) interaction with other active faults. We use this structural characterization to analyse the segmentation of the Baza Fault. According to segmentation criteria, the entire Baza Fault should be considered a single fault seismogenic segment. Consequently, the seismic potential of the fault is defined for a complete rupture. Magnitude for the Mmax event is calculated using several scale relationships, obtaining values ranging between Mw 6.6 and Mw 7.1. Recurrence times range between approximately 2,000 and 2,200 years for Mmax events and between 5,300 and 5,400 years for palaeo-events. A geodetic scenario modelled for an Mmax event of Mw 6.7 shows permanent vertical displacements of more than 0.40m and an overall WSW–ENE extension during entire ruptures of the Baza Fault.This work was funded by the research project TASCUB (RTI2018-100737-B-I00) of the Spanish Ministry of Science, Innovation and Universities, the research group VIGROB053 (University of Alicante), the research project AICO/2019/040 of the Generalitat Valenciana (Valencia regional government), and the research group RNM-325 of the Junta de Andalucía (Andalucia regional government). Iván Medina Cascales was funded by Ph.D. contract FPU16/00202 of the Spanish Ministry of Science, Innovation and Universities. Research partially funded by the Programa Operativo FEDER Andalucía 2014-2020-call made by the University of Jaén 2018

3D geometry and architecture of a normal fault zone in poorly lithified sediments: A trench study on a strand of the Baza Fault, central Betic Cordillera, south Spain

Successive excavation of 13 trenches of different orientations reveals the complexity of a normal fault zone in Pliocene-Pleistocene unconsolidated sediments on a strand of the Baza Fault, central Betic Cordillera, south Spain. These trenches and the excavation floor are interpreted and integrated to reconstruct the 3D geometry and internal architecture of the fault zone. The structure consists of two main fault strands: an eastern one with a few hundred metres throw and a western one with at least 15 m throw. These strands interact and gradually merge to the south, bounding a main deformation zone narrowing from ∼7 to 1 m along strike. Fault-bounded rock bodies, clay and sand smears, and clay injections define the structure. These features are highly variable in 3D. In the northern part of the outcrop, deformation is localized around the main strands, brittle in the west and more ductile to the east. As the strands and their fault zones increasingly interact, fault throw, rock deformation and maturity of the structure increase. Mechanical stratigraphy also controls the style of deformation. A realistic representation of this 4D picture of fault deformation is critical for modelling fluid flow in shallow to possibly deep, faulted sedimentary reservoirs.This research was founded by research group VIGROB053 (University of Alicante)

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)

Tectónica de placas, fallas, terremotos y riesgo sísmico. Una estrategia integradora

Los terremotos son uno de los recursos educativos más atractivos en ciencias de la Tierra. El tratamiento integrado de aspectos del currículo como la tectónica de placas, las fallas, los terremotos y el riesgo sísmico permite al alumnado desarrollar un pensamiento crítico. Los terremotos de Turquía de 2023 se han utilizado de ejemplo para que los alumnos y alumnas valoren las causas reales de esta catástrofe humanitaria

Insights of Active Extension Within a Collisional Orogen From GNSS (Central Betic Cordillera, S Spain)

The coexistence of shortening and extensional tectonic regimes is a common feature in orogenic belts. The westernmost end of the Western Mediterranean is an area undergoing shortening related to the 5 mm/yr NNW‒SSE convergence of the Nubia and Eurasia Plates. In this region, the Central Betic Cordillera shows a regional ENE‒WSW extension. Here, we present GNSS-derived geodetic data along a 170 km-long transect orthogonal to the main active normal faults of the Central Betic Cordillera. Our data indicate that the total extension rate along the Central Betic Cordillera is 2.0 ± 0.3 mm/yr. Extension is accommodated in the eastern (0.8 ± 0.3 mm/yr in the Guadix-Baza Basin) and western (1.3 ± 0.3 mm/yr in the Granada Basin) parts of the Central Betic Cordillera, while no extension is recorded in the central part of the study area. Moreover, our data permit us to quantify, for the first time, short-term fault slip rates of the Granada Fault System, which is one of the main seismogenic sources of the Iberian Peninsula. We deduce a fault slip rate of ∼1.3 ± 0.3 mm/yr for the whole Granada Basin, with 0.9 ± 0.3 mm/yr being accommodated in the Granada Fault System and 0.4 ± 0.3 mm/yr being accommodated in the southwestern sector of the Granada Basin, where no active faults have been previously described at the surface. The heterogeneous extension in the Central Betic Cordillera could be accommodated by shallow high-angle normal faults that merge with a detachment at depth. Part of the active extension could be derived from gravitational instability because of underlying over-thickened crust.This research was funded by the Generalitat Valenciana (Valencian Regional Government, Research project AICO/2021/196), Spanish Ministry of Science, Innovation and University (Research Projects RTI2018-100737-B-I00 and PID2021-127967NB-I00), the University of Alicante (Research Project VIGROB053), the University of Jaén (POAIUJA 2021–2022, CEACTEMA and Programa Operativo FEDER Andalucía, 2014–2020—call made by UJA, 2018, Ref. 1263446), P18-RT-3275 (Junta de Andalucía/FEDER), and the Junta de Andalucía regional government (RNM282 and RNM 148 research groups). The Institut Cartogràfic Valencià, Agencia Valenciana de Seguridad y Respuesta a las Emergencias (Generalitat Valenciana), Consorcio Provincial para el Servicio de Prevención y Extinción de Incendios y Salvamento de Alicante, Excelentísimas Diputaciones Provinciales de Alicante y Castellón, and the Ayuntamiento de Almoradí also provided partial funding

Crustal velocity field in Baza and Galera faults: A new estimation from GPS position time series in 2009 - 2018 time span

The Baza and Galera faults are two active geologic structures located in the central area of the Betic Cordillera (Southern Spain). The goal of our research is to constrain the activity of this faults from high quality GPS measurements to obtain precise deformation rates. In 2008 a GPS survey – mode network was installed to monitor this area. In previous works, we presented a velocity field based on the analysis of some GPS campaigns. Here we show the new results computed from nine GPS campaigns in the timespan 2009-2018. The measurements were done in September 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2017 and 2018. The data process and analysis were performed in Precise Point Positioning by using GIPSYX 1.6 software. GIPSY is a GNSS-inferred positioning software developed by the Jet Propulsion Laboratory. Then, the new estimation of the crustal velocity field is computed from the IGb14 time series by SARI software. The model applied to the original time series, using weighted least squares, consists of an intercept, a site rate and an offset to account for an antenna change. The error term is composed of white noise and temporally correlated random error. The colored noise is described by a random-walk process. We have assumed a typical magnitude for this process of 1.0 mm/√yr. Finally, we discuss the implications of the new results for the tectonic setting and seismic hazard assessment of this key tectonic area of the Betic Cordillera.This work has been funded by Programa Operativo FEDER Andalucía 2014-2020 - call made by University of Jaen in 2018, Ref. 1263446, POAIUJA 2021/2022, CEACTEMA, and RNM148 and RNM282 research groups of Junta de Andalucía

Geodetic fault slip rates on active faults in the Baza sub-Basin (SE Spain): Insights for seismic hazard assessment

One of the most significant parameters for seismic hazard assessment analyses is the fault slip rate. The combination of both geological (long-term) and geodetic (short-term) data offers a more complete characterization of the seismic potential of active faults. Moreover, geodetic data are also a helpful tool for the analysis of geodynamic processes. In this work, we present the results of a local GPS network from the Baza sub-Basin (SE Spain). This network, which includes six sites, was established in 2008 and has been observed for seven years. For the first time, we obtain short-term slip rates for the two active faults in this area. For the normal Baza Fault, we estimate slip rates ranging between 0.3 ± 0.3 mm/yr and 1.3 ± 0.4 mm/yr. For the strike-slip Galera Fault, we quantify the slip rate as 0.5 ± 0.3 mm/yr. Our GPS study shows a discrepancy for the Baza Fault between the short-term slip rates and previously reported long-term rates. This discrepancy indicates that the fault could be presently in a period with a displacement rate higher than the mean of the magnitude 6 seismic cycle. Moreover, the velocity vectors that we obtained also show the regional tectonic significance of the Baza Fault, as this structure accommodates one-third of the regional extension of the Central Betic Cordillera. Our GPS-related slip rates form the basis for future seismic hazard analysis in this area. Our results have further implications, as they indicate that the Baza and Galera Faults are kinematically coherent and they divide the Baza sub-Basin into two tectonic blocks. This points to a likely physical link between the Baza and Galera Faults; hence, a potential complex rupture involving both faults should be considered in future seismic hazard assessment studies.We acknowledge the comments of Editor Prof. Irina M. Artemieva and two anonymous reviewers, which significantly improved the quality of this paper. This research was funded by the Spanish Ministry of Science, Innovation and University (Research Projects: RTI2018-100737-BI00 and CGL2016-80687-R), the University of Alicante (Research Project: VIGROB053), the University of Jaén (PAIUJA 2019-2020 and Programa Operativo FEDER Andalucía 2014-2020 - call made by UJA 2018), the University of Granada (B-RNM-301-UGR18) and the Junta de Andalucía regional government (RNM148, RNM282, and RNM370 and P18-RT-3275 research groups). We thank all observers who collected the data of survey-mode GPS measurements

Geogymkhana Alicante: ingenuity games and outdoor skill for learning Geology

La Geoyincana Alicante es una actividad que se realiza anualmente desde el año 2012 en la que han participado casi 10.000 estudiantes de 4º de la ESO y 1º de Bachillerato. Se desarrolla en un itinerario de algo más de 2 km en el que se alternan paradas con explicaciones directas y pruebas de destreza e ingenio al aire libre. En este trabajo se analizan las siete actividades en las que el aprendizaje se basa en juegos: la carrera del Tiempo Geológico, superposición estratigráfica humana, pictionary geológico, en busca de fósiles, geoselfi geomorfológico, geomimic e historia geológica: el enigma final. La actividad alcanza cada año su objetivo principal que es acercar la Geología a estudiantes y profesorado de una forma atractiva, utilizando las actividades de campo como recurso principal. La evaluación realizada al alumnado y profesorado muestra la valoración positiva de las pruebas basadas en juegos y su idoneidad para comprender mejor los conceptos de geología. A pesar de su carácter extracurricular, la actividad favorece la consecución de objetivos del currículo oficial, ya que favorece la participación activa, el trabajo en equipo, el conocimiento sobre la geología local, la motivación por la ciencia y, en general, el interés por el estudio de la Geología.The Geogymkhana-Alicante is a game-based learning activity carried out annually since 2012. During these years around 10,000 students of secondary school (fourth year of the Compulsory Secondary Education and the first year of Bachillerato) have attended Geogymkhana-Alicante. It consists of a 2 km-long walking trip that combines direct explanations and outdoor skill and ingenuity games. In this paper, we analyse seven of the game-based learning activities of Geogymkhana-Alicante: the geological time race, the human stratigraphic superposition, geological Pictionary, find fossils, the geomorphological geoselfie, geomimic, and geological history: Final Enigma. Each year, these games achieved their main goal: to bring geology to students and teachers in an attractive way using field activities as main resource. We performed a quantitative survey to students and teachers. This survey showed a positive approval of the game-based learning field activities, and their suitability to better understand geological concepts. Despite its extracurricular nature, the activity helps to achieve several objectives of the official curriculum, as it favours the understanding of geological concepts, the knowledge of local geology, teamwork, active participation, and motivation for Geology and Science in a broad way