Person:
Muñoz Martín, Alfonso

First Name

Alfonso

Last Name

Muñoz Martín

URI

https://hdl.handle.net/20.500.14352/75220

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Geológicas

Department

Geodinámica, Estratigrafía y Paleontología

Area

Geodinámica Interna

Identifiers

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Now showing 1 - 10 of 23

Estructura alpina del antepaís ibérico
(Geología de España, 2004) Vicente Muñoz, Gerardo de; Muñoz Martín, Alfonso; Guimerà Rosso, Joan; Vegas, Ramón; Cloetingh, Sierd; Vicente Muñoz, Gerardo de
Relación entre la complejidad estructural frágil y la distribución espacial de la sismicidad en tres regímenes tectónicos diferentes (Sur de Centro América)
(Geotemas, 2000) Muñoz Martín, Alfonso; Arcila, M.; Pérez López, Raúl; Rodríguez Pascua, Miguel Angel; Vicente Muñoz, Gerardo de
Fracturation process is the main geological mechanism for earthquakes generation as well as their magnitude and spatial distribution. In this work we analyze the correlation among a geometric, cinematic and dynamic fault-slip analysis with the magnitude frequency distribution (Ms) and the epicentral setting into three different tectonic areas. In order to compare all these parameters these areas have the same surface (2°x2°) and a similar number of epicentres. The brittle structural complexity has been defined by means an index which depends on the number of active structures as well as the different type of active faults under the present-day stress tensor. The obtained results seem indicate that a bigger index of brittle structural complexity has a good relationship with an increasing of the "b" value and with a bigger complexity in the spatial distribution of earthquakes defined by the fractal dimension (capacity dimension, Dcap).
Análisis de la geometría en profundidad de fracturas conductoras en zonas de baja permeabilidad mediante tomografía eléctrica (El Berrocal, Sistema Central Español)
(Geogaceta, 2007) Muñoz Martín, Alfonso; Olaiz Campos, Antonio José; Vicente Muñoz, Gerardo de; Antón López, Loreto; Elorza, Francisco José; Vicente, Raquel de
The groundwater flow in zones of low permeability, as granites, is mainly associated with zones of fracture. For this reason the characterization of the fractures is fundamental, both in surface as in depth, and must integrate geological information (geological mapping, structural analysis), geophysics (mainly electrical and electromagnetic methods) and geochemistry (radon and others gases) with hydrogeology. In this work we analyze the geophysical response of a strike-slip fault zone by means of three 2D resistivity models. The objective is to investigate the presence of several conductive zones and their geometry in depth. The obtained results allow to control the geometry in depth of the fractures, the gaps between the different mapped traces along the fault zone as well as the thickness of landfill. All this information will be useful for the hidromechanical simulation of the massif, and to check the geometry and gas permeability calculated from emanometry.
Inversion of moment tensor focal mechanisms for active stresses around the Microcontinent Iberia: Tectonic implications
(Tectonics, 2008) Vicente Muñoz, Gerardo de; Cloetingh, Sierd; Muñoz Martín, Alfonso; Olaiz Campos, Antonio José; Stich, Daniel; Vegas, Ramón; Galindo-Zaldívar, Jesus; Fernández Lozano, Javier
The Iberian microcontinent and its connected oceanic crust are affected by deformations related to the Eurasian-African plate boundary. Active stress inversions from populations of moment tensor focal mechanisms have been performed around and inside the Iberian peninsula, using a total of 213 moment tensor estimates. Main results are: 1) The tensorial solutions show better consistency and lower misfits compared to those obtained previously from first P arrival focal mechanisms. 2) Along the Eurasia- Africa western boundary, the type of active stresses progressively changes easternwards from triaxial extension to uniaxial compression along the Terceira Ridge, the Gloria Fault zone and the Gulf of Cadiz. 3) In the Betics-Alboran-Rif zone, uniaxial extension predominates with Shmax N155ºE trending. 4) In N Algeria, uniaxial compression reappears. 5) The Iberian foreland is currently under strike-slip to uniaxial extension tensorial conditions.
El cabalgamiento cenozoico de Boinás (Cordillera Cantábrica, España)
(Geogaceta, 2007) Vicente Muñoz, Gerardo de; González Nistal, S.; Muñoz Martín, Alfonso; Vegas, Ramón; Olaiz Campos, Antonio José; Fernández Lozano, Javier; Vicente, Raquel de
The opencast gold mine of Boinás, has allowed to outcrops the contact between the variscan basement and the Cenozoic sediments. It is observable that the contact is a post - Lower Oligocene thrust, with a N40ºE trend. From a macrostructural point of view, Boinás thrust spreads along more than 10 km with a constant orientation, a vertical gap that reaches 400 m, and a NW vergence. Northwestwards another Alpine thrust develops (Tineo, A l o n s o y Pulgar , 2004) with a parallel orientation an opposite vergence. Between both thrusts a tectonic pop-down appears (Narcea Pop-down). The dynamic analysis shows that this structure was activated by a paleostress tensor with an horizontal s1 trending N139ºE, with a stress regime close to uniaxial compression (R=0.06). This stress allows the geometrical interchanges between s2 and s3. The outcrop also allows to observe a secondary population of normal faults, that fits to an extensional stress tensor (R=0.01) with s3 trending N146ºE, that is coaxial with the main compressive stress tensor. We interpret both fault populations as generated by the tectonic thrust emplacement.
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
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)
Mapa de esfuerzos de Europa a partir de Mecanismos focales calculados desde el Tensor de Momento Sísmico
(Geogaceta, 2006) Olaiz Campos, Antonio José; Vicente Muñoz, Gerardo de; Muñoz Martín, Alfonso; Vegas, Ramón
This work shows a new stress map for Europe obtained from the inversion of earthquakes focal mechanisms calculated with the centroid tensor method (Dzieownski et al., 1982). An amount of 1608 focal mechanisms have been selected with several quality criteria from different catalogues (CMT Harvard, ETH, Med-Net, I.G.N. and I.A.G.) from 1973 to present-day. Values for the maximum horizontal stress and the shape factor of the ellipsoid (horizontal/vertical stress) have been calculated following the Reches (1983) and De Vicente (1988) slip model. The local results have been interpolated to a 1ºx1º regular grid in which the relation between tectonic horizontal stress and vertical load has been taken into account. The final map shows a good correlation with the primary tectonic forces generated in the plate boundaries and the local perturbations related with main crustal heterogeneities as suggested by Gölke and Coblentz (1996).
Los corredores de fallas de Regua-Verin y Vilariça: Zonas de transferencia de la deformación intraplaca en la Península Ibérica
(Geotemas, 2004) Vegas, Ramón; Vicente Muñoz, Gerardo de; Muñoz Martín, Alfonso; Palomino, R.
A substantial part of the intraplate deformation in the Iberian Foreland is transferred from the Cantabro-Pyrenean border by means of two strike-slip deformation belts, the Regua-Verin and Vilariça fault corridors. The Neogene and recent tectonic activity along these intraplate strikeslip belts is responsible for the onset of a geomorphic barrier between the Duero Basin and the Atlantic Margin.
Reactivación intraplaca de un relieve apalachiano: Las Sierras de Guadalupe y Montánchez
(Geotemas, 2004) Álvarez, J.; Muñoz Martín, Alfonso; Vicente Muñoz, Gerardo de; Vegas, Ramón
In this work, we reconcile structural data analysis with géomorphologie observations to better constrain the morphotectonic evolution of the Guadalupe and Montánchez intraplate ranges located in western central Iberia. Fault slip data analysis and geological mapping suggest a global episode of uplift and northwest tilting during Pliocene times. The Hercynian basement was then uplifted by a NW verging thrust developing Plio-Quaternary syntectonic alluvial fans "Raña deposits". The present-day landscape of these ranges should be interpreted as a result of the interaction of (neo) tectonic forcing and longitudinal fluvial erosion.
Cenozoic thick-skinned deformation and topography evolution of the Spanish Central System
(Global and Planetary Change, 2007) Vicente Muñoz, Gerardo de; Vegas, Ramón; Muñoz Martín, Alfonso; Silva Barroso, Pablo Gabriel; Andriessen, Paul; Cloetingh, Sierd; González Casado, José Manuel; Van Wees, Jan Diederik; Álvarez García, Juan; Carbó Gorosabel, Andrés; Olaiz Campos, Antonio José
The Spanish Central System is a Cenozoic pop-up with an E-W to NE-SW orientation that affects all the crust (thick-skinned tectonics). It shows antiform geometry in the upper crust with thickening in the lower crust. Together with the Iberian Chain it constitutes the most prominent mountainous structure of the Pyrenean foreland. The evolutionary patterns concerning the paleotopography of the interior of the Peninsula can be established by an analysis of the following data: gravimetric, topographical, macro and micro tectonic, sedimentological (infilling of the sedimentary basins of the relative foreland), P-T-t path from apatite fission tracks, paleoseismic and instrumental seismicity. Deformation is clearly asymmetric in the Central System as evidenced by the existence of an unique, large (crustal-scale) thrust at its southern border, while in the northern one there is a normal sequence of north verging thrusts, towards the Duero Basin, whose activity ended during the Lower Miocene. This deformation was accomplished under triaxial compression, Oligocene- Lower Miocene in age, marked by NW-SE to NNW-SSE shortening. Locally orientations of paleostresses deviate from that of the regional tensor, following a period of relative tectonic quiescence. During the Upper Miocene-Pliocene, a reactivation of constrictive stress occurred and some structures underwent rejuvenation as a consequence of the action of tectonic stresses similar to those of today (uniaxial extension to strike-slip with NW-SE shortening direction). However, the westernmost areas show continuous activity throughout the whole of the Tertiary, with no apparent pulses. At the present time there is a moderate seismic activity in the Central System related to faults that were active during the Cenozoic, with the same kinematic characteristics.