Person: Muñoz Martín, Alfonso
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First Name
Alfonso
Last Name
Muñoz Martín
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Department
Geodinámica, Estratigrafía y Paleontología
Area
Geodinámica Interna
Identifiers
9 results
Search Results
Now showing 1 - 9 of 9
Item Survey explores active tectonics in Northeastern Caribbean(Eos, Transactions American Geophysical Union, 2005) Carbó Gorosabel, Andrés; Córdoba Barba, Diego; Martín Dávila, José; Ten Brink, Uri S.; Herranz Araújo, Pedro; Von Hilldebrant, Christa; Payero, Juan; Muñoz Martín, Alfonso; Pazos, Antonio; Catalán, Manuel; Granja Bruña, José Luis; Gómez Ballesteros, MaríaThere is renewed interest in studying the active and complex northeastern Caribbean plate boundary to better understand subduction zone processes and for earthquake and tsunami hazard assessments [e.g., ten Brink and Lin, 2004; ten Brink et al., 2004; Grindlay et al, 2005]. To study the active tectonics of this plate boundary, the GEOPRICO-DO (Geological, Puerto Rico-Dominican) marine geophysical cruise, carried out between 28 March and 17 April 2005 (Figure 1), studied the active tectonics of this plate boundary. Initial findings from the cruise have revealed a large underwater landslide, and active faults on the seafloor (Figures 2a and 2c). These findings indicate that the islands within this region face a high risk from tsunami hazards, and that local governments should be alerted in order to develop and coordinate possible mitigation strategies. The cruise collected multibeam bathymetry, gravity, magnetic, high-resolution seismic, deep seismic sounding, and multichannel seismic reflection data, which are currently being processed and interpreted (Table 1). In early November 2005, 10 ocean-bottom seismometers (OBS) that had been deployed northeast of Puerto Rico and the Virgin Islands (Figure 1) during the cruise were recovered. These OBS recorded data during the cruise and the local seismicity between April and October 2005.Item Una década de investigación sobre el geopotencial(Investigación y ciencia, 2011) Catalán, Manuel; Muñoz Martín, AlfonsoItem Gravity modeling of the Muertos Trough and tectonic implications (north-eastern Caribbean)(Marine Geophysical researches, 2010) Granja Bruña, José Luis; Muñoz Martín, Alfonso; Ten Brink, Uri S.; Carbó Gorosabel, Andrés; Llanes Estrada, Pilar; Martín Dávila, José; Córdoba Barba, Diego; Catalán, ManuelThe Muertos Trough in the northeast Caribbean has been interpreted as a subduction zone from seismicity, leading to infer a possible reversal subduction polarity. However, the distribution of the seismicity is very diffuse and makes definition of the plate geometry difficult. In addition, the compressive deformational features observed in the upper crust and sandbox kinematic modeling do not necessarily suggest a subduction process. We tested the hypothesized subduction of the Caribbean plate’s interior beneath the eastern Greater Antilles island arc using gravity modeling. Gravity models simulating a subduction process yield a regional mass deficit beneath the island arc independently of the geometry and depth of the subducted slab used in the models. This mass deficit results from sinking of the less dense Caribbean slab beneath the lithospheric mantle replacing denser mantle materials and suggests that there is not a subducted Caribbean plateau beneath the island arc. The geologically more realistic gravity model which would explain the N–S shortening observed in the upper crust requires an overthrusted Caribbean slab extending at least 60 km northward from the deformation front, a progressive increase in the thrusting angle from 8 to 30 reaching a maximum depth of 22 km beneath the insular slope. This new tectonic model for the Muertos Margin, defined as a retroarc thrusting, will help to assess the seismic and tsunami hazard in the region. The use of gravity modeling has provided targets for future wide-angle seismic surveys in the Muertos Margin.Item Margen Continental Gallego; Zona Económica Exclusiva Española (ZEEE): mapas temáticos de anomalías gravimétricas de aire libre y Bouguer (2012)(2012) Martín Dávila, José; Catalán, Manuel; Larran, M.; Somoza, Luis; León, R.; Gonzalez, F.J.; Carbó Gorosabel, Andrés; Muñoz Martín, Alfonso; Granja, J.L.; Llanes Estrada, P.; Gómez Ballesteros, María; Druet, M.; Acosta, JuanItem Echo-character distribution in the Cantabrian Margin and the Biscay Abyssal Plain(Journal of maps, 2021) Maestro, Adolfo; Gallastegui, Alba; Moreta, Mercedes; Llave, Estefanía; Bohoyo, Fernando; Druet Vélez, María; Navas, Javier; Mink, Sandra; Fernández Sáenz, Fernando; Catalán, Manuel; Gómez Ballesteros, María; Muñoz Martín, Alfonso; Granja Bruña, José LuisIn 2003, 2006–2009, 2014 and 2015, seven oceanographic cruises were carried out onboard the Spanish R/V Hespérides in the Cantabrian Margin and the adjacent abyssal plains, covering anarea of 219,124 km2. Based on the combined analysis and interpretation of the bathymetric and reflectivity data obtained with multibeam echosounders (SIMRADEM12, EM120 and EM1002), and ultra-high-resolution reflection seismic records acquired with the SIMRAD TOPASPS18 parametric sounder, the mapping of the acoustic facies or echo-character at a scale of 1:1,200,000 has been carried out. Thirty types of echoes have been differentiated and gather into four main groups: Distinct, Irregular, Hyperbolic and Undulated. The echo-character depends on the acoustic response of the shallow sediment and these a bed morphology. Therefore, its analysis and characterization are basic for understanding recent and present-day sedimentary processes.Item Cartografía del ecocarácter del Margen Continental de Galicia y de las llanuras abisales adyacentes(Geotemas, 2021) Maestro, Adolfo; Jane, G.; Fernández Saéz, F.; Llave, E.; Bohoyo, Fernando; Navas, Javier; Mink, Sandra; Druet Vélez, María; Gómez Ballesteros, María; Martín Dávila, José; Catalán, Manuel; Carbó Gorosabel, Andrés; Muñoz Martín, Alfonso; Granja Bruña, José LuisLa cartografía y análisis de las facies acústicas que se determinan a partir de la interpretación y correlación de los perfiles sísmicos de muy alta resolución, es una herramienta muy útil para la caracterización de los procesos sedimentarios recientes y su distribución en ambientes marinos profundos. Este trabajo presenta el primer mapa de ecocarácter del Margen Continental de Galicia y las llanuras abisales adyacentes. El mapa se realizó sobre la base del análisis e interpretación de los datos de batimetría y reflectividad de las ecosondas multihaz SIMRAD EM12, EM120 y EM1002, y los perfiles sísmicos de muy alta resolución de la ecosonda paramétrica SIMRAD TOPAS PS18. Sobre la base de la morfología del fondo marino, la reflectividad y los caracteres del eco acústico, se identificaron 26 tipos de ecos en la secuencia sedimentaria más superficial. Estos tipos de eco se han clasificado en cuatro grupos principales: bien definidos, irregulares, hiperbólicos y ondulados. Esta información ha sido adquirida en el marco del ‘Programa de Investigación Científica de la Zona Económica Exclusiva Española’, coordinado por el Ministerio de Defensa, durante las campañas oceanográficas que se han realizado a bordo del BIO Hespérides del 2001 a 2003 y del 2006 a 2009.Item Geomagnetic secular variation of Bransfield Strait (Western Antarctica) from analysis of marine crossover data(Geophysical journal international, 2005) Catalán, Manuel; Agudo, Luis Miguel; Muñoz Martín, AlfonsoTracking the secular variation of the geomagnetic field in the past is severely limited in some cases by factors relating to the remoteness of the sites. This is maximal in the Antarctic where the remote location and severe climate lead to logistic limitations that make it difficult to keep a continuous record of magnetic field variations. From the magnetic information available from historical marine expeditions, it is possible to infer this time-varying component from the comparison of readings at crossovers. This study focuses on this technique, discusses the impact of the different error sources and proposes a simple mathematical procedure to infer average secular variation rates. The result is validated by comparing it with local data from the Arctowski and Livingston magnetic observatories, sited in the area. Additionally, using a high-quality data set from a local area in the neighbourhood of Deception Island, we have detected a systematic distribution in its secular variation. This dichotomy has been interpreted in terms of a volcano-magnetic signal. This fact and the nature of its principal mechanisms are analysed and discussed.Item Bouguer anomalies of the NW Iberian continental margin and the adjacent abyssal plains(Journal of Maps, 2019) Druet Vélez, María; Muñoz Martín, Alfonso; Granja Bruña, José Luis; Carbo Gorosabel, Andrés; Llanes Estrada, María Pilar; Catalán, Manuel; Maestro, Adolfo; Bohoyo, Fernando; Martín Dávila, JoséThe NW Iberian continental margin has a complex structure, resulting from the succession of several rifting episodes close to a ridge triple junction, and a superimposed partial tectonic inversion stage. The wide-ranging physiography matches the diverse tectonic deformation domains related to its evolution. Each deformation domain has a distinctive gravity signal, so the detailed Bouguer anomaly map presented here is a good first approach to the regional study of the whole margin. Moreover, as the presented chart is a complete Bouguer anomaly map (including terrain corrections), its analysis and interpretation can be done in terms of density, geometry and depth variations below the seafloor. This map is mainly based on the dataset obtained during seven one-month surveys carried out in the frame of the Spanish Economic Exclusive Zone project, and also includes two 2 + 3/4D density models illustrating the deep structure of the margin.Item Magnetic anomalies of the NW Iberian continental margin and the adjacent abyssal plains(Journal of maps, 2020) Druet Vélez, María; Catalán, Manuel; Martín Dávila, José; Martos, J.M.; Muñoz Martín, Alfonso; Granja Bruña, José LuisThe NW Iberian margin is a hyperextended continental margin, formed during the opening of the North Atlantic Ocean, where a subsequent partial tectonic inversion has undergone during the Alpine Orogeny. This succession of tectonic episodes determines the magnetic signature of the margin. The Spanish Exclusive Economic Zone Project has carried out seven one-month cruises between 2001 and 2009. To extend and densify the spatial coverage, we have used data from the World Digital Magnetic Anomaly Map. Here, we describe the methodology used for the acquisition and data processing of the magnetic field data. The use of diverse instrumentation, a non-complete external field’s cancelation, and the use of different magnetic core field models, contributed to the total error budget. To reduce it, we have used a leveling algorithm which minimizes all these contributions. Finally, a statistical analysis was applied using crossover residuals, showing a resolution better than 28 nT.