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
3 results
Search Results
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Item Present-Day Crustal Stress Field from Gcmt Focal Mechanisms Based on the Slip Model.(Conference Proceedings, 83rd EAGE Annual Conference & Exhibition, 2022) Olaiz Campos, J. A.; Muñoz Martín, Alfonso; De Vicente Muñoz, GerardoThe Slip Model is applied to the Global Centroid Moment Tensor database to determine the present day state of stress. Thus, from each focal mechanism the horizontal shortening direction (Dey) and the shape factor of the strain ellipsoid (k`), defined as the relationship between the maximum horizontal shortening and the vertical axis, are calculated. Additionally, this method proposed the neoformed plane from the calculated nodal planes. In this study, to determine the stress configuration at crustal scale, only depths < 40 km are included. Focal mechanisms are grouped in reverse, strike-slip and normal, to analyse its distribution and to determine the b-parameter from Gutenberg-Richter law. Finally, global shape factor and horizontal shortening direction maps are presented.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.Item Along-strike segmentation in the northern Caribbean plate boundary zone (Hispaniola sector): Tectonic implications(Tectonophysics, 2020) Rodríguez Zurrunero, Álvaro; Granja Bruña, José Luis; Muñoz Martín, Alfonso; Leroy, Sylvie; Ten Brink, Uri S.; Gorosabel-Araus, J.M.; Gómez de la Peña, Laura; Druet Vélez, María; Carbó Gorosabel, AndrésThe North American (NOAM) plate converges with the Caribbean (CARIB) plate at a rate of 20.0 ± 0.4 mm/yr. towards 254 ± 1º. Plate convergence is highly oblique (20-10º), resulting in a complex crustal boundary with along-strike segmentation, strain partitioning and microplate tectonics. We study the oblique convergence of the NOAM and CARIB plates between southeastern Cuba to northern Puerto Rico using new swath multibeam bathymetry data and 2D multi-channel seismic profiles. The combined interpretation of marine geophysical data with the seismicity and geodetic data from public databases allow us to perform a regional scale analysis of the shallower structure, the seismotectonics and the slab geometry along the plate boundary. Due to differential rollback between the NOAM oceanic crust north of Puerto Rico and the relative thicker Bahamas Carbonate Province crust north of Hispaniola a slab tear is created at 68.5ºW. The northern margin of Puerto Rico records the oblique high-dip subduction and rollback of the NOAM plate below the island arc. Those processes have resulted in a forearc transpressive tectonics (without strain partitioning), controlled by the Septentrional-Oriente Fault Zone (SOFZ) and the Bunce Fault Zone (BFZ). Meanwhile, in the northern margin of Hispaniola, the collision of the Bahamas Carbonate Province results in high plate coupling with strain partitioning: SOFZ and Northern Hispaniola Deformed Belt (NHDB). In the northern Haitian margin, compression is still relevant since seismicity are mostly associated with the deformation front, whereas strike slip earthquakes are hardly anecdotal. Although in Hispaniola intermediate-depth seismicity should disappear, diffuse intermediate-depth hypocenter remains evidencing the presence of remnant NOAM subducted slab below central and western Hispaniola. Results of this study improve our understanding of the active tectonics in the NE Caribbean that it is the base for future assessment studies on seismic and tsunamigenic hazard.