Tomografía sísmica vertical inversa 2.5D alrededor del sondeo científico Almera-1, ICTJA-CSIC, Barcelona

En 2011 junto al Instituto de Ciencias de la Tierra Jaume Almera-CSIC, en Barcelona, se perforó un sondeo científico con el objeto de disponer de una infraestructura destinada a la investigación con sondas de testificación geofísica, monitorización de sondeos, la formación especializada y también para la exploración del subsuelo urbano. La extracción de testigo continuo y un completo estudio mediante sondas de testificación geofísica del ICTJA-CSIC, permitieron caracterizar la sección geológica, estructuras atravesadas y características hidrogeológicas en el sondeo Almera-1. Se presentan aquí los resultados obtenidos en una exploración sísmica de la estructura en el entorno del sondeo y el reconocimiento de la estructura en la que está emplazado el mismo. En este contexto se planteó una tomografía sísmica vertical inversa pseudo-3D (o 2.5D), cuyo dispositivo experimental, metodología y resultados son objeto de este trabajo. Se define la estructura en el entorno del sondeo y se establece una correlación entre las respuestas geofísicas y los distintos tramos de materiales reconocidos en el subsuelo.Peer Reviewe

Prospección sísmica en el Glaciar Johnsons, Isla Livingston (Antártida). (campañas antárticas 1996-1997 y 1997-1998)

During two Antarctic summers (1996-97 and 1997-98), five seismic refraction (2.685 m long) and two reflection profiles (2.980 m long) were acquired on Johnsons Glacier (Livingston Island, Antarctica) in order to obtain information about the structure of the ice, characteristics of the ice-rock contact and the basement topography. Seismic refraction is an efficient method for calculating ice thickness and seismic waves velocity; whereas the seismic reflection is recommended because it leads us to a clear seismic image of bedrock topography and ice-bed contact. This study was completed using a raw data analysis (wavefront) which detected ice crevasses and delineated sectors with different glacier structures (accumulation and ablation zones). The information obtained from seismic data about the internal structure of the glacier constrains the glacial dynamics of Johnsons Glacier

Prospección sísmica en el Glaciar Johnsons, Isla Livingston (Antártida). (campañas antárticas 1996-1997 y 1997-1998)

Durante las campañas antárticas de 1996-97 y 1997-98, se realizaron en el glaciar Johnsons (Isla Livingston, A n t á rtida) cinco perfiles sísmicos de refracción (con un total de 2.685 m longitud) y dos perfiles de reflexión (2.980 m longitud) con el objetivo de obtener información sobre el grosor del hielo y la topografía del basamento. En cuanto a la sísmica de refracción, se presenta como un método eficaz para la obtención del espesor y de la velocidad del hielo, mientras que se propone la sísmica de reflexión como la técnica más adecuada para obtener información sobre la morfología de la cubeta glacial y el contacto hielo-roca. Los resultados aportados por los anteriores métodos se han completado con un análisis minucioso de los datos de campo (estudio del frente de ondas) obteniéndose la localización de sectores con fracturas (grietas) y pudiéndose distinguir áreas de distintas características glaciológicas (zonas de acumulación y ablación). Este conocimiento de la estructura interna del glaciar mediante prospección sísmica junto con otros datos glaciológicos permitirá modelizar la dinámica del flujo del glaciar Johnsons.During two Antarctic summers (1996-97 and 1997-98), five seismic refraction (2.685 m long) and two reflection profiles (2.980 m long) were acquired on Johnsons Glacier (Livingston Island, Antarctica) in order to obtain information about the structure of the ice, characteristics of the ice-rock contact and the basement topography. Seismic refraction is an efficient method for calculating ice thickness and seismic waves velocity; whereas the seismic reflection is recommended because it leads us to a clear seismic image of bedrock topography and ice-bed contact. This study was completed using a raw data analysis (wavefront) which detected ice crevasses and delineated sectors with different glacier structures (accumulation and ablation zones). The information obtained from seismic data about the internal structure of the glacier constrains the glacial dynamics of Johnsons Glacier

Aplicação de métodos geofísicos em Arqueologia: desenvolvimento de metodologias eficazes de prospecção geofísica aplicadas a diferentes ambientes arqueológicos

The use of geophysical methods applied to Archaeology, in the exploration of buried structures in the sub-surface, is an imperative need in the previous steps to excavations or archaeological surveys, playing an important role in the delimitation of archaeological sites, making it more effective protective actions archaeological heritage. With regard to planning an archaeological exploration, geophysical methods significantly reduce the runtime and operating costs, guiding with acceptable accuracy for local archaeologist digging and what to look for. The development of efficient methods in geophysical exploration, applied to different archaeological environments usually requires the crossing of different geophysical techniques. The methodologies for the application of geophysical surveys shall concern either in the steps of the data acquisition either in the steps of the obtained data processing and in the result representation. This work presents the results for two techniques, georadar and magnetometry, in different archaeological locations, showing the differences between the different archaeological sites, whose features are different

Caracterización de la Falla de Alhama de Murcia mediante MASW

The deep structure of the Alhama de Murcia Fault (AMF) is characterized by means of the analysis of surface waves identified in shallow high resolution seismic reflection data. Multichannel analysis of surface waves (MASW) is used to unravel the 2-D S-wave velocity model and image the depth geometry of the fault system. The study area includes segments of the fault located in La Salud area. Two approaches have been used to achieve a well constrained velocity model in the AMF fault zone. Conventional seismic reflection processing work flow has been used to clean the seismic data and increase its S/N ratio. Occam’s approach has been used to invert the digitized surface wave dispersion curves. 1D shear wave velocity-depth profiles were estimated in shot and CDP domains. Relatively well resolved 2D velocity-depth models were obtained by com- posite of the 1D Velocity-depth functions. These composite 2D-velocity models are able to constrain the depth geometry of the fault zone up to 100 m depth. The fault zone is indicated by a relatively broad low velocity anomaly that correlates with the fault’s surface expression.La estructura profunda de la falla de Alhama de Murcia (AMF) ha sido caracterizada mediante el análisis de ondas superficiales identificados en datos de reflexión sísmica superficial de alta resolución. El análisis multicanal de ondas de superficie (MASW) es usado para desentrañar un modelo 2D de Vs y para obtener imágenes de la geometría del sistema de fallas en profundidad. El área de estudio incluye segmentos de la AMF ubicados en el área de La Salud. Se han utilizado dos enfoques para lograr modelos de velocidad bien restringidos de la zona de falla. Por un lado, se han limpiado los datos utilizado un flujo de procesado convencional diseñado para aumentar su ratio de señal/ruido. Por el otro, se ha usado el enfoque de Occam para invertir las curvas de dispersión de ondas de superficie digitalizadas. Los perfiles 1D de profundidad de las Vs fueron estimados en los dominios de disparo y de CDP. Se obtuvieron modelos de velocidad-profundidad 2D relativamente bien resueltos mediante la interpolación de las funciones de velocidad-profundidad 1D. Estos modelos de velocidad 2D ayu- dan a restringir en profundidad la geometría de la zona de falla hasta los 100 m que se caracteriza por una anomalía de baja velocidad relativamente amplia que se correlaciona en la superficie con la expresión de la falla.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEMinisterio de Ciencia e Innovación (MICINN)ICTJA-CSICMinistry of Education and Culture of the Republic of Indonesiapu

Early life stages of a Mediterranean coral are vulnerable to ocean warming and acidification

The ability of coral populations to recover from disturbance depends on larval dispersion and recruitment. While ocean warming and acidification effects on adult corals are well documented, information on early life stages is comparatively scarce. Here, we investigate whether ocean warming and acidification can affect the larval and juvenile development of the Mediterranean azooxanthellate coral Astroides calycularis. Larvae and juveniles were raised for 9 months at ambient (23 &deg;C) and warm (26 &deg;C) temperatures and ambient (8.0) and low pH (7.7, on the total scale). The timing of the larvae metamorphosis, growth of the juvenile polyp, and skeletal characteristics of the 9-month-old polyps were monitored. Settlement and metamorphosis were more successful and hastened under a warm temperature. In contrast, low pH delayed the metamorphosis and affected growth of the recruits by reducing the calcified area of attachment to the substrate, as well as by diminishing the skeleton volume and the number of septa. However, skeleton density was higher under low pH and ambient temperature. The warm temperature and low pH treatment had a negative impact on the survival, settlement, and growth of recruits. This study provides evidence of the threat that represents ocean warming and acidification for the larval recruitment and the growth of recruits of A. calycularis.</p

Investigating active faults in SE Iberia: borehole and surface seismic monitoring

Monitoring seismic signal associated to active faults in SE Iberia was undertaken by the installation of 3-component geophone strings in boreholes and also on the surface, close to active faults located in Torreperogil-Sabiote area and Baza basin. Our instrumentation was installed in existing hydrogeological and geotechnical boreholes for continuous monitoring of low intensity seismic activity during 8 months. Borehole geophone strings consisting of 8 receivers of 3-component, with 15Hz of natural frequency, spaced 6 m at depth were used. The main purpose of continuous monitoring of the seismic signal in the subsurface was to record the high frequencies of the seismic data and to investigate and eventually characterize fault creep and seismic noise related to deformation and fault movements in seismically active areas. The dataset recorded included a series of low magnitude earthquakes and is being analyzed to identify and characterize seismic events. A 3G GSM module was used together with the acquisition system in order to guarantee remote access to check the acquired data quality and to control the acquisition parameters. Also, the remote access allowed us to pre-process the data 'in situ' and to perform only selective transmission of the most relevant files. Because of the isolated and remote locations of some of the monitoring stations, proprietary software was developed to avoid the possible losses of communication between the acquisition system and remote control computer. In this contribution we present the most relevant features of the acquisition and methodology implemented for this acquisition, first results of the field experiment and data processing and advantages of the on site pre-processing management and remote operation of the acquisition system. This system is being applied to other active fault zones in the area.Peer Reviewe

Caracterización sísmica de la falla de Alhama de Murcia

La falla de Alhama de Murcia (AMF) es una de las fallas más activas de la Península Ibérica y fue la causante del terremoto de Lorca de 2011 que significó numerosos daños materiales e incluso víctimas mortales. Esta falla oblicua en dirección NE-SO, que se extiende por más de 100 km, ha sido estudiada en superficie pero poco se sabe de su estructura en profundidad. Esto es especialmente importante para poder interpretar de forma correcta los numerosos datos paleosísmicos que se están obteniendo, ya que conocer la relación estructural en profundidad de las distintas ramas que forman la AMF es esencial. Por este motivo, y dentro del marco del proyecto InterGEO, se ha realizado una campaña de adquisición de datos sísmicos 2D a lo largo de la AMF, centrándose en los segmentos más interesantes en la zona de Lorca-Totana. Aquí se presentan los los resultados preliminares del procesado de algunos de los perfiles adquiridos en esta campaña que muestran la primera imagen estructural de la falla en profundidad y que permitirá entender el comportamiento de dicha falla, así como determinar su relevancia desde el punto de vista del riesgo sísmico.Este trabajo ha podido ser realizado gracias a la financiación de los proyectos CGL2014-56548-P, 2009-SGR-1595, 2009-SGR-1595.Peer Reviewe

Pectin methyl esterases and rhamnogalacturonan hydrolases: weapons for successful Monilinia laxa infection in stone fruit?

The secretion of cell wall‐degrading enzymes is one of the mechanisms used by necrotrophic fungi to colonize host tissues. However, information about virulence factors of Monilinia spp., the causal agents of brown rot in stone fruit, is scarce. Plant cell walls have three main components that are broken down by fungal enzymes: cellulose, hemicellulose and pectin. In order to identify Monilinia laxa candidate proteins involved in pectin hydrolysis, two in vitro approaches were conducted: (i) phenotypic and ecophysiological characterization of growth of the pathogen at different pHs, in glucose‐ and pectin‐containing solid media for 7 days' incubation; and (ii) expression analysis of genes encoding M. laxa pectin methyl esterases (MlPMEs) and rhamnogalacturonan hydrolases (MlRG‐HYDs) after incubation for 0.5, 2, 6, 24 and 48 h in glucose‐ and pectin‐containing liquid media. Phenotypic tests showed the role of carbon source on M. laxa growth rate and aggressiveness, and indicated that pectinases were greatly affected by pH. Gene expression analyses uncovered differences among members of each family of pectinases and between the two families, defining sets of genes expressed at earlier (0.5–6 h) and later (48 h) phases. Notably, the up‐ or down‐regulation of these target genes was carbon source‐dependent. Finally, an in vivo study confirmed the synergistic and complementary role that these genes play in the M. laxa–stone fruit pathosystem. Based on these results, it is hypothesized that MlPME2, MlRG‐HYD1 and MlRG‐HYD2 may be potential virulence factors of M. laxa in the process from infection to colonization.info:eu-repo/semantics/acceptedVersio

GPR Clutter Reflection Noise-Filtering through Singular Value Decomposition in the Bidimensional Spectral Domain

Usually, in ground-penetrating radar (GPR) datasets, the user defines the limits between the useful signal and the noise through standard filtering to isolate the effective signal as much as possible. However, there are true reflections that mask the coherent reflectors that can be considered noise. In archaeological sites these clutter reflections are caused by scattering with origin in subsurface elements (e.g., isolated masonry, ceramic objects, and archaeological collapses). Its elimination is difficult because the wavelet parameters similar to coherent reflections and there is a risk of creating artefacts. In this study, a procedure to filter the clutter reflection noise (CRN) from GPR datasets is presented. The CRN filter is a singular value decomposition-based method (SVD), applied in the 2D spectral domain. This CRN filtering was tested in a dataset obtained from a controlled laboratory environment, to establish a mathematical control of this algorithm. Additionally, it has been applied in a 3D-GPR dataset acquired in the Roman villa of Horta da Torre (Fronteira, Portugal), which is an uncontrolled environment. The results show an increase in the quality of archaeological GPR planimetry that was verified via archaeological excavation