8 research outputs found
Present-Day Crustal Stress Field from Gcmt Focal Mechanisms Based on the Slip Model.
The 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
Alpine kink bands on foliated rocks of the Central System variscan basement
La asociación espacial y cinemática entre kink bands en rocas con foliación varisca y cabalgamientos alpinos en el basamento del Sistema Central, permiten deducir que los primeros tienen una edad cenozoica, y no varisca o tardivarisca. Sistemáticamente, la dirección de los ejes de los kinks es subparalela a los cabalgamientos. Se estudian tres afloramientos clave: El Cabalgamiento de Villares de Jadraque, el Cabalgamiento de Valdesotos y el Retrocabalgamiento de El Atazar.The spatial and kinematic association between kink bands in
rocks with variscan foliation and alpine thrusts in the Central System basement, allow us to deduce that the former have a Cenozoic age, and not variscan or late-variscan. Systematically, the fold axes trend of the kinks is sub-parallel to the strike of the thrusts. Three key outcrops are studied: the Villares de Jadraque thrust, the Valdesotos
thrust and the El Atazar back-thrust.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu
Analysis of changes in the association of income and the utilization of curative health services in Mexico between 2000 and 2006
<p>Abstract</p> <p>Background</p> <p>A common characteristic of health systems in most developing countries is unequal access to health services. As a result, members of the poorest population groups often do not receive formal attention for health services, because they cannot afford it. In 2001 in Mexico, to address income-related differences in the use of health services, the government launched a major healthcare reform, which includes a health insurance program called <it>Seguro Popular</it>, aimed at improving healthcare access among poor, uninsured residents. This paper analyzes the before and after changes in the demand for curative ambulatory health services focusing on the association of income-related characteristics and the utilization of formal healthcare providers vs. no healthcare service utilization.</p> <p>Methods</p> <p>By using two nationally representative health surveys (ENSA-2000 and ENSANUT-2006), we modeled an individual's decision when experiencing an illness to use services provided by the (1) Ministry of Health (MoH), (2) social security, (3) private entities, or (4) to not use formal services (no healthcare service utilization).</p> <p>Results</p> <p>Poorer individuals were more likely in 2006 than in 2000 to respond to an illness by using formal healthcare providers. Trends in provider selection differed, however. The probability of using public services from the MoH increased among the poorest population, while the findings indicated an increase in utilization of private health services among members of low- and middle-income groups. No significant change was seen among formal workers -covered by social security services-, regardless of socioeconomic status.</p> <p>Conclusions</p> <p>Overall, for 2006 the Mexican population appears less differentiated in using healthcare across economic groups than in 2000. This may be related, in part, to the implementation of <it>Seguro Popular</it>, which seems to be stimulating healthcare demand among the poorest and previously uninsured segment of the population. Still, public health authorities need to address the remaining income-related healthcare utilization differences, the differences in quality between public and private health services, and the general perception that MoH facilities offer inferior services.</p
3D crustal-scale structure of the West Iberia margin: a novel approach to integrated structural characterization of passive margins
Hyperextended margins are very heterogeneous along the entire length of the margin, so the definition of tectonic domains made exclusively from 2D seismic sections presents serious limitations. In this work we present an approach of the 3D crustal-scale structure of the West Iberia margin (WIM) by modelling eight lithospheric sections, using seismic, wells and gravity data. The continuous nature of gravity data allowed us to propose a new map of tectonic domains within the WIM. Maps of total horizontal (THD) and vertical gradients (dZ) of Bouguer anomaly have been calculated and compared with other criteria such as the crustal structure and thinning factor. This comparative analysis has been carried out on a section proposed as a model for the Western Iberian Margin (Tugend et al. in Tectonics, 2014; Cadenas et al. in Tectonics 37:758–785, 2018), and on four 2 + 1/2D gravimetric models transversal to the margin. The results point out a significant variation in the absolute values of Bouguer anomaly, thinning factor and crustal structure along the margin and, therefore, of the position of the different domain boundaries. Clear patterns that correlating the Bouguer anomaly signal and its derivatives to the tectonic domain are evidenced. Most significantly, the necking-zone and its transition to the hyperextended domain are characterized by high values of the THD of the Bouguer anomaly. The observed patterns in Bouguer anomaly and its derivatives provide a solid constraint for mapping the boundaries between different tectonic domains along the margin, even in those areas where limited deep seismic information could lead to uncertain interpretations. The results of this work can also inform on the general kinematics of the WIM
Gravimetric and magnetic analysis of salt diapirs in the offshore of the Asturias basin
En este trabajo se analizan mediante campos potenciales (gravimetría y magnetismo) las estructuras salinas interpretadas previamente en el offshore de la Cuenca de Asturias. Para ello se han realizado los mapas de anomalías y tres modelos en 2+3/4D GRAV/MAG con datos coincidentes con un cubo sísmico 3D adquirido por Repsol en 2008. El análisis cuantitativo de los mapas y la modelización en 2+3/4D ha permitido reinterpretar la estructura del basamento y de las estructuras salinas hasta ajustar la señal GRAV/MAG. Estas modificaciones son significativas por debajo de los niveles de evaporitas, destacando la necesidad de introducir menor cantidad de sal, y una reinterpretación de la geometría del techo del basamento.In this work a potential field analysis (gravimetry and magnetism) of the salt structures interpreted in the offshore of the Asturias Basin. For this purpose, 2D processing of the anomaly maps and three models in 2+3/4D GRAV/MAG have been carried out with the data that coincide with a 3D seismic cube acquired by Repsol in 2008. The quantitative analysis of the maps and modeling has allowed the revaluation of the structure of the basement and salt structures until adjusting the GRAV/MAG signal. These modifications are significant below the levels of evaporites, highlighting the need to introduce less salt, and a new geometry of the basement top.Ministerio de Ciencia e Innovación (MICINN)Comunidad de MadridDepto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu