Person:
Giner Robles, Jorge Luis

First Name

Jorge Luis

Last Name

Giner Robles

URI

https://hdl.handle.net/20.500.14352/81990

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Geológicas

Area

Geodinámica Interna

Identifiers

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Now showing 1 - 10 of 21

Bransfield Basin, Antarctic Peninsula: Not a normal backarc basin
(Geology, 2000) González-Casado, J.M.; Giner Robles, Jorge Luis; López-Martínez, J.
The Bransfield Basin, a marginal basin located northwest of the Antarctic Peninsula, has been habitually considered as a backarc basin associated with the rollback process that took place along an inactive plate boundary, the South Shetland Trench, where the Antarctic and the Phoenix plates meet. New geophysical and structural data discussed in this paper show that the basin opening is related to a sinistral simple-shear couple between the Scotia and the Antarctic plates, and not to the previously suggested rollback mechanism. The widening of the Bransfield Basin and the lack of trench retreat are causing compression in the South Shetland Islands. Two different neotectonic stress directions, with interchanged stress axes, are found in the area of the South Shetland block.
Calibración de la constante de difusión (k0) para la datación de escarpes cosísmicos: aplicación al terremoto de Alborax (Albacete, SE España)
(Contribuciones al Estudio del Periodo Cuaternario, 2007) Pérez López, Raúl; Rodríguez Pascua, Miguel Angel; Giner Robles, Jorge Luis; Calvo Sorando, José Pedro; Garduño Monroy, V.H.; Israde Alcántara, I.; Bischoff, James L.; Lario Gómez, Javier; Silva Barroso, Pablo Gabriel
The diffusion equation was formulated to estimate the age of fault scarps. This technique is rather simple, taking into account the degradation of the unconsolidated scarp with the time. The Tobarra-Cordovilla segment consists in a surface rupturing associated to undated paleoearthquakes. This segment configures a graben basin with normal faults affecting Quaternary deposits. Preliminary study of the paleoearthquake indicates a magnitude greater than 5.5. As a primary approach, we have applied the Diffusion Equation in order to delimitate the age interval of occurrence. However, the diffusion constant for such equation (K0) is only calibrated for arid environmental. Therefore, we have introduced a new equation to obtain the K0-value according the fault throw, the erodability and the apparent density of the unconsolidated faulted sediment.
The recent (upper miocene to quaternary) and present tectonic stress distributions in the Iberian Peninsula
(Tectonics, 2000) Herraiz Sarachaga, Miguel; Vicente Muñoz, Gerardo De; Lindo-Ñaupari, R.; Giner Robles, Jorge Luis; Simón, J.L.; González-Casado, J.M; Vadillo, O.; Rodríguez-Pascua, M.A.; Cicuéndez, J.I.; Casas, A.; Cabañas, L; Rincón, P.; Cortés, A.L.; Ramírez, M.; Lucini, M.
A general synthesis of the recent and present stress situation and evolution in the Iberian Peninsula was obtained from microstructural and seismological analysis. The stress evolution was deduced from (1) fault population analysis (FPA) from 409 sites distributed throughout the Iberian Peninsula, (2) paleostress indicators given by 324 stations taken from the bibliography, and (3) seismic data corresponding to 161 focal mechanisms evenly spread in the studied region. The application of FPA together with the determination of stress tensors and focal mechanisms for the whole Iberian microplate has provided two main results: (1) the Iberian Peninsula is undergoing a NW-SE oriented compression, except for the northeastern part (Pyrenees, Ebro Basin, and Iberian Chain), where it is N-S to NE-SW, and the Gulf of Cádiz, where it seems to be E-W, and (2) the main trends of the stress field have remained almost constant since the upper Miocene. The analysis performed by zones suggests the presence of local heterogeneities in the stress field.
Caracterización geoeléctrica de los depósitos superficiales en la Antártida Occidental (Isla Livingstone, Islas Shetland del Sur, Antártida Occidental)
(Geogaceta, 2000) Muñoz Martín, Alfonso; Giner Robles, Jorge Luis; González Casado, José Manuel; López Martínez, Jerónimo; Durán Valsero, Juan José; Gumiel, Pablo; Serrano, Enrique
The geophysical study of superficial deposits (mainly gravels) in ice-free areas near the seashore in the South Shetland Islands (Antarctica) allows establishing the possible existence of permafrost and buried ice bodies. In this work we have investigated the internal structure of Quaternary sediments using the resistivity method (vertical electric sounding, V.E.S.), with the purpose of establishing the resistivity values of the different materials and their geometry. We present here the results obtained from 17 vertical electric soundings carried out in Caleta Española, (north coast of Hurd Peninsula), and in the surroundings of Caleta del Glaciar Rocoso (south coast of Hurd Peninsula), both in Livingston Island. Vertical electric soundings interpretation has allowed us to characterise different units from the resistivity values (active layer, permafrost, buried ice, Quaternary deposits and their basement), and to establish the inter-phase between sea water and continental water. Moreover, with the resistivity method we have deduced the spatial distribution of some of these beds. In this way the permafrost (with resistivity values ranging between 13000 and 35000 Ω*m), and the associated active layer, is restrained to shallow depths(< 2 m) and located in the surveyed areas faraway from the seaside (i.e. mainly in the upper raised beaches). Buried ice under coarse Quaternary deposits have resistivity values of one major order magnitude than the permafrost (> 60000 Ω *m) and has been only found in the studied rock glacier.
Análisis de las deformaciones y esfuerzos recientes y su relación con la sismicidad en el borde oriental de la cuenca del Tajo (España Central)
(Boletín Geológico y Minero, 2003) Muñoz Martín, Alfonso; Vicente Muñoz, Gerardo de; Giner Robles, Jorge Luis
La cuenca del Tajo es un área de actividad sísmica baja pero con evidencias geológicas de actividad neotectónica. Para establecer su evolución reciente se han analizado las deformaciones y esfuerzos recientes, a partir de 794 planos de falla con estrías repartidas en 40 estaciones de análisis. Los resultados muestran la presencia de un campo de esfuerzos extensivo principal un eje de extensión horizontal (SHMIN) NO-SE, y un campo secundario en régimen de desgarre con la misma orientación de SHMIN. Este campo secundario aparece asociado a zonas de fractura previas de orientación NE-SO, y es simultáneo con el campo extensivo. El estudio de la sismicidad incluye la construcción de cuatro nuevos mecanismos focales de terremotos, y su análisis conjunto con los datos previamente publicados. La inversión de esfuerzos aplicada a los planos nodales de los terremotos ha permitido calcular la presencia coetánea de dos tensores de esfuerzos activos en la cuenca del Tajo: Uno en régimen compresivo, próximo a desgarre, con una dirección del máximo esfuerzo horizontal (SHMAX) según NO-SE, y un tensor minoritario de tipo extensivo con SHMIN según NO-SE. Este tensor extensivo lo interpretamos como el producto de una permutación entre σ1 y σ3 en la zona externa superficial de una flexión antiformal de escala cortical descrita previamente (Giner, 1996; Andeweg et al., 1999; Cloetingh et al., 2002)
Geometrie analysis and scaling properties of calcite e-twins in the Cameros Basin (NW Iberian Chain, Spain)
(Geotemas, 2004) Gumiel, Pablo; González Casado, José Manuel; Campos, R.; Giner Robles, Jorge Luis; García Cuevas, C.
One dimensional geometric analysis has been carried out in several scan lines from 885 measures of twins in calcite grains to determine grain width (in microns) and twin density (number of twins.mm-1 ) distributions. Grain width and twin density have a good fit to the log-normal frequency distribution. Twinning in calcite implies intracrystaline deformation mechanism with low shear stress. When the process begins low grain width and calcite twins are developed with a probably random distribution what could be supported by a negative exponential distribution tendency. The twinning process continues until a "critical" value of grain width and density which is going to influence in the scaling process, and becoming the distribution to log-normal type. But some data also conform to a power-law (fractal) frequency distribution from determined range or sizes (300 to WOO mm) and density (2 to W twins.mm-1) with some superimposed random (negative-exponential) elements, possible due to the irregularities at grain scale, but also because this systems show multifractal behavior.
Determinación de valores absolutos de paleoesfuerzos, basados en el maclado de la calcita, en el frente norte de la Sierra de Cameros (Cordillera Ibérica).
(Geotemas, 2004) González Casado, José Manuel; García Cuevas, C.; Gumiel, Pablo; Giner Robles, Jorge Luis; Moreno, A.
Calcite e-twin density (twins/mm) and percentage of calcite grains with one and two twin sets from sparry grains that fill microveins were used to precise the differential stress related with the inversion of the Cameros Basin, a Mesozoic sedimentary basin located in the northwestern part of Iberian Chain (Spain). The results obtained using techniques based on the percentage of twined grains yield better results that those techniques based on twin density. The deduced stress magnitudes fit well with the differential stress interval proposed for fold-thrust belt domains. Combination of twin data with rock mechanics data provides adequate estimations of differential stresses.
Colapsos cosísmicos y paleosismicidad en la sima de Benis (Cieza, SE España), asociados al terremoto de Mula (1999; VII mks; Mb = 4,8)
(Contribuciones al estudio del periodo cuaternario, 2007) Pérez López, Raúl; Martínez Díaz, José Jesús; Rodríguez Pascua, Miguel Angel; Silva Barroso, Pablo Gabriel; Giner Robles, Jorge Luis; Bejar Pizarro, Marta; Marcos Nuez, A.; Calvo Sorando, José Pedro; Lario Gómez, Javier; Silva Barroso, Pablo Gabriel
In this work we present the first conclusions obtained from the morphotectonic and seismotectonic analysis of the Benis Cave (Cieza, SE of Spain). Both analyses provide new descriptions of seismic structures formed during a known instrumental earthquake and a new type of paleoseismic feature or seismothem (a migrating coral flowstone). From the last seismothem, at least two paleoearthquakes have been identified within the cave. During the Mula earthquake (mb = 4.8, MSK VII, 1999), a massive collapse of metric blocks at -156m was reported. This direct effect caused by a low magnitude earthquake shows the high sensitivity of caves to seismic shaking in this area.
Present-day strain field on the South American slab underneath the Sandwich Plate (Southern Atlantic Ocean): A kinematic model
(Special publication - Geological Society of London, 2009) Giner Robles, Jorge Luis; Pérez López, Raúl; Rodríguez Pascua, Miguel Angel; Martínez Díaz, José Jesús; González Casado, J.M.
This work analyses the present-day principal strain orientation on the downgoing slab of the South America Plate (SAM) beneath the Sandwich Plate (SAND). The strain regime was deduced from the study of 331 earthquake focal mechanism solutions examined by fault population analysis methods. In the slab, the maximum horizontal shortening direction (ey) rotates in trend in a clockwise direction from NE in the north, to SE in the south. Based on this rotation, three different areas were defined according to the prevailing focal mechanism type: (1) the North Zone, with ey oriented N058°E and reverse and strike-slip focal mechanisms; (2) the Central Zone, with only reverse focal mechanisms and ey striking N080°E; and (3) the South Zone, with ey oriented N1068E and reverse and strike-slip focal mechanisms. The strain field in the North Zone of the SAND involves decoupling of the slab at approximately 70 km depth. In contrast, the South Zone edge slab exhibits no decoupling and it exhibits different geometry (hook-like shaped) from the North Zone. Finally, we define the dextral strike-slip component acting at the South Sandwich Fracture Zone (SSFZ), according to focal mechanism solutions and the regional tectonic configuration.
The 7 June 2007 mbLg 4.2 escopete earthquake : An event with significant ground motion in a stable zone (Central Iberian Peninsula)
(Seismological research letters, 2008) Carreño, Emilio; Benito, B.; Martínez Solares, José Manuel; Cabañas, Luis; Giner Robles, Jorge Luis; Murphy, P.; López, C.; Del Fresno, Carmen; Alcalde, J.M.; Gaspar Escribano, Jorge M.; Antón, R.; Martínez Díaz, José Jesús; Cesca, Simone; Izquierdo, A.; Sánchez Cabañero, J.G.; Expósito, P.
An earthquake occurred on 7 June 2007 at 01h:42m:09.5s (UTC) with geographical coordinates 40°.41N, 2°.98W and magnitude mbLg = 4.2 according to the Seismic national network (RSN) of Madrid's Instituto Geográfico Nacional (IGN). The epicenter was located close to the town of Escopete, where the earthquake was felt with intensity IV, waking up inhabitants and causing widespread alarm. Historically, rare but similar events have been felt in the area, near the towns of Pastrana (1922) and Duron (1982). Nevertheless, this part of Iberia experiences very low seismic activity. The earthquake with the largest magnitude recorded to date by the RSN since the mid-1920s was 4.1. Due to low seismicity values, the hazard map of the Norma de la Construcción Sismorresistente Española (Spanish seismic building code; NCSE-02) establishes a basic acceleration value of less than 0.04 g, which is the threshold value for the application of the earthquake-resistant building code. However, this value was exceeded in strong-motion recordings during the 2007 event. An important consideration is the existence of two nuclear power plants in the Guadalajara administrative province: José Cabrera and Trillo. Strong-motion instruments at the José Cabrera nuclear power plant (JCNPP) recorded a peak ground acceleration (PGA) value of 0.07g. This is the first acceleration recording made from central Iberia and also one of the highest values read from instruments to date for the whole of the Iberian peninsula. This paper presents an overview of the results of our multidisciplinary analysis of the earthquake, which we researched in terms of its regional and local tectonic setting, local seismicity, focal mechanics, strong-motion records, and macroseismic effects.