334 research outputs found

    Using travertine deformations to characterize paleoseismic activity along an active oblique-slip fault: the Alhama de Murcia fault (Betic Cordillera, Spain)

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    A preliminary paleoseismic study of trave rtine deposits cut by an active oblique-slip fault is presented. The Alhama de Murcia fault affects late Pleistocene and Holocene travertine deposits along the Lorca-Totana segment. Travertines along oblique-slip (reverse-sinistral) active faults have not been reported. On the Alhama de Murcia fault, CaCO3 rich springs are linked to an extensional step-ove rand to releasing fault junctions in a reverse-sinistral fault zone. The sampling methodology for U/Th dating employed to avoid contamination (by choosing material from a geochemical closed system) is described. A petrographic analysis is necessary to ensure the quality of the samples. Terrace-mound, fissure-ridge, eroded sheets and range-front trave rtine deposits occur in the Alhama de Murcia fault zone. At Carraclaca a 15 m amplitude monocline fold was formed by the reverse movement of this fault which has been active since the late Pleistocene. The first available absolute ages for deformed and undeformed travertines yield a vertical slip rate of 0.08mm/yr. It is possible to estimate 4818 yr of recurrence time for the northern branch given the slip per event on alluvial deposits in the southern branch of the Alhama de Murcia fault

    Tectónica activa de la Falla de Alhama de Murcia, Cordillera Bética, España

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    We present an overview of the knowledge of the structure and the seismic behavior of the Alhama de Murcia Fault (AMF). We utilize a fault traces map created from a LIDAR DEM combined with the geodynamic setting, the analysis of the morphology, the distribution of seismicity, the geological information from E 1:50000 geological maps and the available paleoseismic data to describe the recent activity of the AMF. We discuss the importance of uncertainties regarding the structure and kinematics of the AMF applied to the interpretation and spatial correlation of the paleoseismic data. In particular, we discuss the nature of the faults dipping to the SE (antithetic to the main faults of the AMF) in several segments that have been studied in the previous paleoseismic works. A special chapter is dedicated to the analysis of the tectonic source of the Lorca 2011 earthquake that took place in between two large segments of the fault.En este estudio se presenta una revisión del conocimiento que hasta la actualidad se tiene de la estructura y comportamiento sismogenético de la Falla de Alhama de Murcia (AMF). Se utiliza un nuevo mapa de la traza de la AMF realizado a partir de un modelo digital del terreno de alta resolución a partir de datos LIDAR, combinado con el análisis del marco geodinámico, la geomorforlogía, la distribución espaciotemporal de la sismicidad, la información geológica de trabajos previos y los datos paleosísmicos existentes, para describir la actividad reciente de la AMF. Se discute la importancia de las incertidumbres que se mantienen en relación con la estructura y la cinemática de la AMF para la correcta interpretación y correlación espacio-temporal de los datos paleosísmicos obtenidos hasta ahora. En particular, se discute la naturaleza de las fallas con buzamiento SE en superficie (antitéticas con las fallas principales de la AMF que bordean las sierras) en varios segmentos que han sido estudiados en análisis paleosismológicos previos. Se dedica un capítulo especial al análisis de la fuente geológica del terremoto de Lorca de 2011 que tuvo lugar en la zona de intersegmento que separa dos de los segmentos de mayor longitud de la AMF

    Time- and space-resolved spectroscopic characterization of laser-induced swine muscle tissue plasma

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    10 págs.; 12 figs.; 1 tab.The spatial-temporal evolution of muscle tissue sample plasma induced by a high-power transversely excited atmospheric (TEA) CO2 pulsed laser at vacuum conditions (0.1–0.01 Pa) has been investigated using high-resolution optical emission spectroscopy (OES) and imaging methods. The induced plasma shows mainly electronically excited neutral Na, K, C, Mg, H, Ca, N and O atoms, ionized C+, C2 +, C3 +, Mg+, Mg2 +, N+, N2 +, Ca+, O+ and O2 + species and molecular band systems of CN(B2Σ+–X2Σ+), C2(d3Πg–a3Πu), CH(B2Σ−–X2Π; A2Δ–X2Π), NH(A3Π–X3Σ−), OH(A2Σ+–X2 Σ+), and CaOH(B2Σ+–X2Σ+; A2Π–X2Σ+). Time-resolved two-dimensional emission spectroscopy is used to study the expanded distribution of different species ejected during ablation. Spatial and temporal variations of different atoms and ionic excited species are reported. Plasma parameters such as electron density and temperature were measured from the spatio-temporal analysis of different species. Average velocities of some plasma species were estimated. © 2015 Elsevier B.V. All rights reserved.We gratefully acknowledge the support received in part by the DGICYT (Spain) Project MICINN: CTQ2013-43086-P for this research. The authors wish to thank the Geomaterials2 Program (S2013/MIT 2914) supported by the Comunidad de Madrid and EU structural and cohesion funds (FSE and FEDER).Peer reviewe

    Evidence for coseismic events of recurrent prehistoric deformation along the Alhama de Murcia fault, southeastern Spain

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    The Alhama de Murcia fault is a 85 km long oblique-slip fault, and is related to historical and instrumental seismic activity. A paleoseismic analysis of the Lorca-Totana sector of the fault containing MSK I=VIII historical earthquakes was made in order to identify and quantify its seismic potential. We present 1) the results of the neotectonic, structural and geomorphological analyses and, 2) the results of trenching. In the study area, the Alhama de Murcia fault forms a depressed corridor between two strands, the northwestern fault with morphological and structural features of a reverse component of slip, bounding the La Tercia range to the South, and the southeastern fault strand with evidence of sinistral oblique strike-slip movement. The offset along this latter fault trapped the sediments in transit from the La Tercia range towards the Guadalentín depression. The most recent of these sediments are arranged in three generations of alluvial fans and terraces. The first two trenches were dug in the most recent sediments across the southeastern fault strand. The results indicate a coseismic reverse fault deformation that involved the sedimentary sequence up to the intermediate alluvial fan and the Holocene terrace deposits. The sedimentary evolution observed in the trenches suggests an event of temporary damming of the Colmenar creek drainage to the South due to uplifting of the hanging wall during coseismic activation of the fault. Trench, structural and sedimentological features provide evidence of at least three coseismic events, which occurred after 125,000yr. The minimum vertical slip rate along the fault is 0.06mm/yr and the average recurrence period should not exceed 40,000yr in  accordance with the results obtained by fan topographic profiling. Further absolute dating is ongoing to constrain these estimates.

    Tectónica activa de la Cuenca de Málaga: evidencias en marcadores morfotectónicos (Cordillera Bética Occidental, España)

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    The Malaga Basin is located in the westernmost part of the Betic Cordillera. This alpine cordillera in the south of Spain is the most active region of the Iberian Peninsula. Some of the most destructive earthquakes occurred historically in Spain took place within the Malaga Basin. In this work we focus on geomorphic and morphotectonic observations in the aim of finding active tectonic structures that could be seismogenic sources. First, we study the spatial arrangement and age of the Quaternary alluvial fan system as well as the drainage pattern of the basin, followed by the analysis of the distribution of regional markers like marine erosive surfaces and the extend of Pliocene marine deposits in the Malaga Basin. The tectonic structures inferred as active by the morphotectonic analysis are grouped into four main families: N60º-85ºE folds associated with blind thrust faults, N20º-30ºE and N40º-50ºE high angle dip-slip faults, and N165º-170ºE tear faults. Finally, their seismic potential in terms of maximum moment magnitude (Mw) is assessed by means of empirical relationships, varying between 6.0 and 7.0 depending on the hypothesis considered.La cuenca de Málaga se sitúa en la parte más occidental de la cordillera Bética. En esta cordillera alpina del sur de España se han localizado algunos de los terremotos más destructivos ocurridos históricamente en la península Ibérica. En este trabajo se estudian algunos de los aspectos geomorfológicos de la cuenca del Málaga con el fin de identificar las estructuras tectónicas activas que pudiesen ser fuentes sismogénicas. Se estudia la distribución y edad del sistema de abanicos aluviales de la cuenca, así como la red de drenaje. También se analiza la distribución regional de marcadores tectónicos pliocenos, como superficies de erosión marina y los depósitos sedimentarios de este periodo transgresivo. Se han identificado varias estructuras tectónicas activas que han sido agrupadas en cuatro familias: pliegues N60º-85ºE asociados con falla inversas ciegas, fallas de alto buzamiento con salto en la vertical N20º-30ºE y N40º-50ºE, y fallas de transferencia N165º-170ºE. En base a relaciones empíricas se ha estimado un potencial sísmico para las fallas identificadas, obteniéndose valores de magnitud momento (Mw) entre 6,0 y 7,0

    Magnetotelluric Characterization of the Alhama de Murcia Fault (Eastern Betics) - Preliminary Results

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    The Lorca Earthquake (11/5/2011, Mw 5.2) stands as the most destructive in Spain over the last 50 years. It was interpreted as having occurred in an intersegment zone of the strike-slip Alhama de Murcia Fault (AMF). Within the research project “Intergeosima”, a multi parametric characterization and monitoring of the fault structure is ongoing, with the aim of developing a future Near Fault Observatory (NFO) to improve the understanding of the seismic behaviour of the fault in the short and medium term. In this work we present the preliminary results of a magnetotelluric (MT) survey carried out along the rambla de la Torrecilla (SW of Lorca). A more resistivity area might correspond to the Quaternary units, whereas the conductive areas might delineate the extent of the fault gauge materials. Further analysis and inversion of the data are necessary to obtain a more detailed picture of the extension and geometry below the fault zone

    Improvement of a functional method to determine the design thermal transmittance of building façades. Implementation in southern Spain

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    The thermo-hygrometric conditions to which construction materials are subjected cause their thermal performance to vary by location. These variations must be characterised in order to design building envelopes adjusted to the requirements of each situation, thus contributing to improve their energy efficiency under actual operating conditions. To this end, a functional calculation procedure that corrects the standardised thermal conductivity values of façade materials (¿-value) has been recently proposed; which considers the climatic characteristics of each location. This work proposes and validates improvements that, while preserving its functionality, overcome some limitations of the original procedure. To calculate more accurate corrections, the façade configuration and the climatic zones established by the building codes are also considered, allowing a more reliable characterisation of the design thermal transmittance of each building façade. By using climatic records gathered from 316 weather stations, a detailed isopleth map is also developed to present the applicable corrections for more than 250, 000 km2 of southern Spain. The largest ¿-value corrections are identified on the southeast coast and reach up to +6% in the summer months (with average annual corrections above +4%). This improved procedure can be extrapolated to any national building code that establishes constant values of thermal conductivity for façade materials and that defines thermal design requirements based on climatic zones

    Contribución a la peligrosidad sísmica de las fallas activas de la zona intraplaca de Iberia: la Falla Alentejo-Plasencia

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    We present the earthquake potential characterisation of the Alentejo-Plasencia Fault (APF) in the intraplate area of the Iberian Peninsula. The APF displays clear deformation of geomorphic surfaces and sediments of Neogene and younger age and, thus, we consider it to be active within the current tectonic regime. APF fault slip rate values range from 0.01 to 0.1 mm/yr with a preferred value of 0.05 mm/yr. Mw associated to fault rupture ranges from 6.6 to 8.7 using different segmentation models (segments ranging from 20 to 500 km) and various fault scaling relationships. Recurrence intervals derived from slip rate and Mw range from 10 ka to 4 Ma, with preferred values between 20 and 30 ka. Other faults in the interior of Iberia present similar values. Hazard curves produced using all fault sources from the intraplate Iberia show that active faults of the intraplate Iberia do not contribute significantly to seismic hazard at short return periods typical of the building codes (~ 500 year return periods). However, they can be important contributors to hazard at critical facilities (high hazard dams, nuclear power plants, emergency response buildings) where return periods of interest may be 10,000 years or more. Our fault source characterisation is very preliminary (with large uncertainties) and further detailed studies of active faults across the whole plate boundary are required to confirm the values for the intraplate faults presented here.En este trabajo se presenta la caracterización del potencial sísmico de la falla Alentejo-Plasencia (APF) situada en la región intraplaca de la Península Ibérica. La APF muestra una clara deformación de superficies geomorfológicas y sedimentos de edad neógena y más reciente, de modo que la consideramos una falla activa dentro del régimen tectónico vigente. Los valores de velocidad de movimiento de la APF van de 0.01 a 0.1 mm/yr con un valor preferido de 0.05 mm/yr. El valor de magnitud Mw asociada a la falla oscila entre 6.6 y 8.7 utilizando diferentes modelos de segmentación (con longitudes de segmento que van de 20 a 500 km) y varias relaciones de escala. Los intervalos de recurrencia derivados de la velocidad de movimiento y de la Mw oscilan de 10 Ka a 4 Ma, estando los valores preferidos entre los 20 Ka y los 30 Ka. Otras fallas en el interior de Iberia presentan valores similares. Las curvas de peligrosidad generadas utilizando todas las fallas-fuente de la zona intraplaca de Iberia muestran que las fallas activas de esta zona no contribuyen de forma significativa a la peligrosidad sísmica para los cortos periodos de retorno generalmente considerados en los códigos de construcción (para períodos de retorno de ~ 500 años). Sin embargo, dichas fallas pueden contribuir de modo importante a la peligrosidad sísmica para instalaciones críticas (presas de elevado riesgo, centrales nucleares, edificios de servicios de emergencia) donde los periodos de retorno de interés pueden ser de 10.000 años o más. Nuestra caracterización de la falla como fuente sismogénica es muy preliminar (presenta importantes incertidumbres) y se requieren estudios detallados adicionales de las fallas activas a lo largo de todo el límite de placa para confirmar los valores de las fallas intraplaca presentados aquí

    The effect of self-efficacy expectations in the adherence to a gluten free diet in celiac disease

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    Objective: To analyse the effect of general and specific self-efficacy on the adherence to a gluten free diet (GFD) in patients with celiac disease along with the effect of other relevant variables. Design: 271 patients with celiac disease participated in this transversal descriptive study and completed a series of questionnaires regarding adherence (CDAT), general self-efficacy (GSES) and specific self-efficacy (Celiac-SE) and quality of life (CD-Qol), among others. Main Outcome Measures: Dependent variable was adherence to the Gluten Free Diet (GFD). Main independent variables were general self-efficacy, specific self-efficacy and quality of life. Model tests were conducted using regression analysis. Results: 71.9% of patients show an excellent or good adherence to the diet. Higher levels of adherence are positively associated to a high expectancy of specific self-efficacy, to the perceived adoption of recommended behaviours, risk perception and better quality of life (these variables accounted for 36.4% of the variance in the adherence to a GFD, p <.001). Conclusions: Specific self-efficacy rather than general has a predictive value in adherence to a GFD. Therefore, we need to develop and transculturally adapt new instruments to assess specific self-efficacy. Celiac-SE has proved to be a useful scale for this objective
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