Flood Response to Solar Activity in the Tagus Basin (Central Spain) over the Last Millennium     

Gerardo Benito  Andrés Díez-Herrero  María Fernández de Villalta 《Climatic change》2004,66(1-2):27-28

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Spatial distribution, morphometry and activity of La Puebla de Alfindén sinkhole field in the Ebro river valley (NE Spain): applied aspects for hazard zonation     

F. Gutiérrez-Santolalla  M. Gutiérrez-Elorza  C. Marín  G. Desir  C. Maldonado 《Environmental Geology》2005,48(3):360-369

A highly active collapse sinkhole field in the evaporitic mantled karst of the Ebro river valley is studied (NE Spain). The subsidence is controlled by a NW-SE trending joint system and accelerated by the discharge of waste water from a nearby industrial state. The morphometry, spatial distribution and temporal evolution of the sinkholes have been analysed. The volume of the sinkholes yields a minimum estimate of average lowering of the surface by collapse subsidence of 46 cm. The clustering of the sinkholes and the tendency to form elongated uvalas and linear belts, in a NW–SE direction have a predictive utility and allow the establishment of criteria for a hazard zonation. With the precipitation record supplied by a pluviograph and periodic cartographic and photographic surveys the influence of heavy rainfall events on the triggering of collapses has been studied.  相似文献   

Subsidence hazard avoidance based on geomorphological mapping in the Ebro River valley mantled evaporite karst terrain (NE Spain)   总被引：1，自引：6，他引：1  

F. Gutiérrez-Santolalla  M. Gutiérrez-Elorza  C. Marín  C. Maldonado  P. L. Younger 《Environmental Geology》2005,48(3):370-383

In the valley of the Ebro River to the southeast of the city of Zaragoza (NE Spain), the dissolution of evaporite sediments (gypsum, halite and Na-sulphates) which underlie alluvial deposits gives rise to numerous sinkholes. These sinkholes are a potential hazard to human safety, particularly where they develop in a catastrophic way. Even slow-developing sinkholes are problematic, as they damage urban and agricultural infrastructure, necessitating costly repairs and vigilant maintenance. To assist in developing avoidance strategies for these hazards, the factors controlling sinkhole occurrence have been assessed using geomorphological maps produced from aerial photographs for 1956 and 1981. Important controls on sinkhole development are found to include underlying geological structure (manifest in preferred orientations of sinkholes on the azimuths N130-150E and N30-40E), and the presence of glauberite in the groundwater flow path, which apparently promotes accelerated gypsum dissolution. Perhaps surprisingly, alluvium thickness does not appear to significantly correlate with the density of sinkholes on the floodplain in this area. The maps for 1956 and 1981 reveal that both human activity and natural processes can serve to obscure the true density of sinkhole development. For instance, a large number of sinkholes which were conspicuous in 1956 have since been back-filled by farmers. In the most fluvially active zone of the Ebro valley (the meander belt), the relatively low density of sinkholes compared with adjoining zones suggests that subsidence is being masked by morpho-sedimentary dynamic processes (aggradation and erosion). Careful geomorphological mapping for different time periods yields a much more accurate impression of the frequency of sinkhole development than would be gained from surveying currently visible sinkholes in the area of interest.  相似文献   

Calibration of Four Species of Tillandsia as Air Pollution Biomonitors   总被引：1，自引：0，他引：1  

Eduardo D. Wannaz  María L. Pignata 《Journal of Atmospheric Chemistry》2006,53(3):185-209

Many organisms have been used as bioindicators of atmospheric contamination, with moss and lichen species being the most common. However, studies using epiphytic vascular species of Tillandsia have shown a good correlation between the presence of pollutants and the bioindicator's response. Therefore, the aim of our investigation was to calibrate and compare the response of four Tillandsia species of Argentina to ascertain whether they could be used as atmospheric contamination biomonitors. For this, we analysed the correlation between the levels of heavy metals in total atmospheric deposition samples and: a) their rate of enrichment; b) the physiological response of the plant samples. Tillandsia samples collected from a non contaminated area in the province of Córdoba were transplanted to four areas in the capital city with different sources of pollution (industrial or traffic emissions). They were exposed for a period of 3 to 6 months after which the concentrations of Pb, Ni, Fe, Zn, Cu and S as well as the physiological parameters of foliar damage were determined. Simultaneously samples of total atmospheric deposition were also taken.The highest level of metal enrichment was found in T. capillaris followed by T. tricholepis, T. permutata and T. retorta. Also, the use of a foliar damage index proved to be effective and could be a useful tool to evaluate different levels of atmospheric quality in these species. The rate of heavy metal deposition was higher in the industrial area for all metals except for Zn whose values were higher in areas with high levels of traffic.  相似文献   

Salt-water intrusion and nitrate contamination in the Valley of Hermosillo and El Sahuaral coastal aquifers, Sonora, Mexico   总被引：1，自引：0，他引：1  

Birgit Steinich  Oscar Escolero  Luis E. Marín 《Hydrogeology Journal》1998,6(4):518-526

 The Valley of Hermosillo coastal aquifer, state of Sonora, northwestern Mexico, has been over-exploited for the last four decades, in order to maintain agricultural activity in one of the most important irrigation districts of the Mexican Republic. The over-exploitation has resulted in the development of several drawdown cones and in the lowering of the water table to as much as 50 m below mean sea level. Contamination of the aquifer in the form of salt-water intrusion from the Gulf of California and high nitrate concentrations is the consequence of human activities. A hydrogeochemical zonation of the aquifer, based on the presence of different water families, led to the identification of a coastal band approximately 30 km wide that is affected by salt-water intrusion. Conductivity of the sampled water and the interpretation of the ratio Na/Cl×1000 was used to identify the location of three major intrusion plumes in this coastal band. The background nitrate contamination of the aquifer is about 4 ppm, but contents as great as about 17 ppm occur in some wells. Irrigation with raw sewage and movement of contaminants in areas of high hydraulic gradients within the drawdown cones probably are responsible for localized peaks of the nitrate concentration. Received, October 1996 Revised, September 1997, May 1998 Accepted, July 1998  相似文献   

Poets and narrators from Mendoza and their local perceptions     

Prof.  Dr. María E. de Civit Furlani  Prof.  Dr. María J. de Manchón Gutiérrez 《GeoJournal》1996,38(1):109-118

This article outlines three modalities of relation between literature and geography: the literary work as demonstrative element, the literary work as collective image, and the literary work as analogous process. The verification of the three modalities takes place through an approachment to the local literature using a geographical concept, namely region, and a particular area: the province of Mendoza, in western Argentina. Ten literary works of different genre were selected to which content analysis was applied. First the relevance of these representations at the initiation of geographical research is verified and then the way in which they stimulate the definition of problems and the formulation of hypotheses is addressed.  相似文献   

Large Scale Rockfall Reach Susceptibility Maps in La Cabrera Sierra (Madrid) performed with GIS and Dynamic Analysis at 1:5,000   总被引：1，自引：0，他引：1  

Ayala-Carcedo  Francisco J.  Cubillo-Nielsen  Silvia  Alvarez  Ana  Domínguez  María J.  Laín  Luis  Laín  Ricardo  Ortiz  Guillermo 《Natural Hazards》2003,29(3):325-340

For the testing of the effect on the tsunami prevention facilities, a simplified methodfor tsunami risk assessment was suggested without wave run-up analysis. This methodis proposed using calculated offshore tsunami waveform and field reconnaissance suchas the seawall height, time necessary for residents' evacuation and tsunami warninginsurance. Then, two normalized values are evaluated; one is the ratio of calculatedmaximum tsunami height to seawall height, the other is the ratio of time betweentsunami over-topping and evacuation completion to total time required for evacuation.These two values are used to qualitatively estimate the safety of residents and the effectof tsunami prevention facilities, eliminating the necessity to compute complicatedtsunami run-up onshore.  相似文献   

Establishing habitat-specific indicator species in Tierra del Fuego with freshwater macroinvertebrates     

Christopher B. Anderson  Montana Johnson  María Eugenia Lopez 《新西兰海洋与淡水研究杂志》2018,52(1):145-154

As a tool to understand Tierra del Fuego’s basic ecology and detect changes due to human pressures, this study develops habitat bioindicators. We compared the freshwater benthic macroinvertebrates at 61 study sites in six habitat types: grassland streams, urbanised streams, forested streams, beaver ponds, lakes and peat bog ponds. Forty-nine taxa were identified; insects were the most diverse group. Beaver pond, lake and grassland stream assemblages were similar, as were those from lakes, grassland streams and peat bog ponds. Fourteen taxa were habitat-specific. In forests, these included mayfly scrapers (Andesiops, Meridialaris) and blackfly filterers (Gigantodax). In lakes, two copepod filterers were indicators, and in urban streams, one shredder (Aphroteniella) and three collector-gatherers (springtail, earthworm, aquatic worm). Predators (Corixa, Aeshna) were characteristic of peat bog ponds. Beaver ponds had no indicator species. Establishing links between species and ecosystems constitutes the beginning of a broader effort to understand anthropogenic impacts to Fuegian watersheds.  相似文献   

Analysis of the goodness of empirical approaches in predicting explosive detonation parameters     

Fernando?G.?BastanteEmail authorView author&#;s OrcID profile  Elena?Alonso  María?Araújo  Julio?García Menéndez 《Stochastic Environmental Research and Risk Assessment (SERRA)》2018,32(9):2605-2618

Goodness of empirical models for predicting explosive detonation velocity and pressure was analysed using 3 databases consisting of experimental velocity and pressure measurements for different explosives. The first database was used to estimate experimental errors for detonation velocity and pressure measurements. The second database was used to compare residuals obtained by the experimental models and by various thermochemical codes. Finally, the third database, consisting of some 600 data on 130 explosive substances, was used to estimate residual bias and dispersion resulting from the application of the experimental models. Also analysed was model coherence with the ideal detonation theory. Our main conclusion is that all the models introduce bias in their predictions depending on the density and oxygen balance values of the explosive. Of those analysed, the Xiong model was notable for its good results, with residual dispersion comparable to that obtained from application of the best thermochemical codes. Our results would indicate that the Xiong model is the only model that may be compatible with the ideal detonation theory. The pressure equation derived from the ideal detonation theory and calibrated with experimental data had excellent predictive capacity.  相似文献   

New insights into asymmetric folding by means of the anisotropy of magnetic susceptibility,Variscan and Pyrenean folds (SW Pyrenees)     

Belén Oliva-Urcia  Inma Gil-Peña  Ruth Soto  José María Samsó  Borja Antolín  Emilio L. Pueyo 《Studia Geophysica et Geodaetica》2018,62(2):291-322

Magnetic fabric allows to unravel the petrofabrics of sedimentary rocks and to assess their deformational history. The use of this technique, in addition to classical structural field observations in the limbs of seven asymmetric folds in the Pyrenees, helps to determine the differences of internal deformation as well as the folding kinematics. Three folds developed during the Variscan Orogeny in Ordovician and Devonian rocks, and four folds developed during the Pyrenean Orogeny in Eocene rocks, are studied. Folds show a variety of structural locations, in different thrust sheets of the Southern Central Pyrenees, different cleavage development, age, geometry and lithology. Sampling follows an equivalent lithological layer in the two limbs, except for one case, of the selected folds. Results show a modified tectonic magnetic fabric in most sites with the magnetic lineation on the tectonic foliation plane. A larger scattering of the magnetic lineation (maximum magnetic anisotropy axis) and a higher intensity of the preferred orientation of minerals (eccentricity of the anisotropy of magnetic susceptibility - AMS ellipsoid) is better observed in the overturned (short) limb of the asymmetric Variscan folds than in the normal (long) limb. On the other hand, the shape parameter in Alpine folds is generally larger in the overturned (short) limb then in the normal (long) one. A good clustering of the minimum magnetic anisotropy axes is observed in all limbs. The combination of the AMS data with the structural data helps to understand and better constrain the deformation degree in these asymmetric folds and to unravel the deformational history.  相似文献