Strong ground motion estimation in the Sea of Marmara region (Turkey) based on a scenario earthquake   总被引：1，自引：0，他引：1  

Nelson Pulido  Anibal Ojeda  Kuvvet Atakan  Tetsuo Kubo 《Tectonophysics》2004,391(1-4):357

We perform a broadband frequency bedrock strong ground motion simulation in the Marmara Sea region (Turkey), based on several fault rupture scenarios and a source asperity model. The technique combines a deterministic simulation of seismic wave propagation at low frequencies with a semi-stochastic procedure for the high frequencies. To model the high frequencies, we applied a frequency-dependent radiation pattern model, which efficiently removes the effective dependence of the pattern coefficient on the azimuth and take-off angle as the frequency increases. The earthquake scenarios considered consist of the rupture of the closest segments of the North Anatolian Fault System to the city of Istanbul. Our scenario earthquakes involve the rupture of the entire North Anatolian Fault beneath the Sea of Marmara, namely the combined rupture of the Central Marmara Fault and North Boundary Fault segments. We defined three fault rupture scenarios based on the location of the hypocenter, selecting a preferred hypocentral location near a fault bend for each case. We analysed the effect of location of the asperity, within the Central Marmara Fault, on the subsequent ground motion, as well as the influence of anelasticity on the high-frequency attenuation characteristics. The fault and asperity parameters for each scenario were determined from empirical scalings and from results of kinematic and dynamic models of fault rupture. We calculated the resulting time series and spectra for ground motion at Istanbul and evaluated the sensitivity of the predictions to choice of model parameters. The location of the hypocenter is thus shown to be a critical parameter for determining the worst scenario earthquake at Istanbul. We also found that anelasticity has a significant effect on the regional attenuation of peak ground accelerations. Our simulated ground motions result in large values of acceleration response spectra at long periods, which could be critical for building damage at Istanbul during an actual earthquake.  相似文献   

An electoral geography of Western Europe     

Christian Vandermotten  Pablo Medina Lockhart 《GeoJournal》2000,52(2):93-105

The European Parliament elections give the opportunity to map voting behaviour in Western Europe. The main methodological difficulty is related to the classification of the parties. The cleavage theory is not a sufficient basis for an operational typology. The left-right axis remains an important basis for a classification. We have discriminated three groups of parties (the left, including the ecologists; the moderate centre-right and classical right; a growing populist reactionary right and the extreme-right, with a different geographical pattern). Beyond those families, the regionalist parties can also be isolated. The green voting pattern is more specific to the central regions and not linked to that of the traditional left, which is related to the traditions of the workers' movement or more specific to the peripheral regions. In general, the metropolitan regions vote more to the left than the surrounding regions, today more and more often on the basis of an intellectual voting pattern, including some well to-do urban and periurban districts. The centre-right and classical right voting pattern designate two main spaces: a conservative mid-European area, with a strong Christian-democracy in the Catholic countries with a quite recent State building (however recently collapsed in Italy), and rural peripheral spaces, mainly those dominated for a long time by small familial rural enterprises and/or by strong and conservative religious practices. At the European scale, the new populist reactionary right is stronger in the `central' regions than the traditional extreme right, even if the latter is also present in some central deprived urban and old industrial districts.  相似文献   

Deterministic computer-aided optimum design of rock rubble-mound breakwater cross-sections, by W. de Haan     

Joseph R. Medina 《Coastal Engineering》1992,17(3-4)

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Cyclical salt efflorescence weathering: an invisible threat to the recovery of underground mine environment for tourist exploitation     

J. Matías Peñas Castejón  J. Francisco Maciá Sánchez  Mª Pilar Jiménez Medina  Mª Jesús Peñalver Martínez 《Environmental Earth Sciences》2014,72(6):1901-1913

Enhancing the value of an underground mine environment for tourist exploitation involves altering the physico-chemical balance of stone materials whose original mechanical properties guaranteed the structural stability of the site’s galleries and chambers. Humidity and temperature changes caused by the public exhibition of this kind of assets are the main causes of such disorders. After the intervention in the Agrupa-Vicenta mine in La Union (Spain) there were still runoff-water leaks into the mine. These water runoffs through the fault and schistosity planes of the enclosing rock mass give rise to salt precipitation over time. Adapting this mine and turning it into a museum have meant a decrease in relative indoors humidity and an increase in temperature. These variations have caused rocks, which were stable in the original conditions, to increase their rate of physico-chemical weathering due to the polycyclic supergene alteration of the metal sulfides they contain. The resulting release of sulfates into the solution and their subsequent precipitation as single and double salt efflorescence causes haloclasty, deteriorating the rock’s mechanical properties and diminishing the structural stability of the operation. This paper presents the results of characterizing the supergene mineral phases of salt efflorescence in the rock bed enclosing an underground sulfide mine value enhanced for tourist exploitation. Dangers for the structural stability of this type of architectural intervention, associated to the formation of efflorescences, are also identified; these efflorescences are caused by the weathering of rocks that make up its supporting structure.  相似文献   

The magmatic- and hydrothermal-dominated fumarolic system at the Active Crater of Lascar volcano,northern Chile     

F. Tassi  F. Aguilera  O. Vaselli  E. Medina  D. Tedesco  A. Delgado Huertas  R. Poreda  S. Kojima 《Bulletin of Volcanology》2009,71(2):171-183

Low-to-high temperature fumaroles discharging from the Active Crater of Lascar volcano (northern Chile) have been collected in November 2002, May 2005 and October 2006 for chemical and isotopic analysis to provide the first geochemical survey on the magmatic-hydrothermal system of this active volcano. Chemical and isotopic gas composition shows direct addition of high-temperature fluids from magmatic degassing, mainly testified by the very high contents of SO₂, HCl and HF (up to 87,800, 29,500 and 2,900 μmol/mol) and the high R/Ra values (up to 7.29). Contributions from a hydrothermal source, mainly in gas discharges of the Active Crater rim, has also been detected. Significant variations in fluid chemistry, mainly consisting of a general decrease of magmatic-related compounds, i.e. SO₂, have affected the fumarolic system during the period of observation, indicating an increase of the influence of the hydrothermal system surrounding the ascending deep fluids. The chemical composition of Active Crater fumaroles has been used to build up a geochemical model describing the main processes that regulate the fluid circulation system of Lascar volcano to be utilized in volcanic surveillance.  相似文献   

Gas tracer transport through a heterogeneous fracture zone under two phase flow conditions: Model development and parameter sensitivity     

Jorge Jodar  Agustín Medina  Jesús Carrera 《Advances in water resources》2009

Large amounts of gas can result from anaerobic corrosion of metals and from chemical and biological degradation of organic substances in underground repositories for radioactive waste. Gas generation may lead to the formation of a gas phase bubble and to the migration of radioactive gaseous species. Transport occurs in, at least, in two forms: (1) gas bubble, migration is controlled by advection, dispersion and diffusion in the gas phase, and (2) within water pockets, the dissolved species migrate mainly by diffusion. We consider a two-dimensional system representing an isolated heterogeneous fractured zone. A dipole gas flow field is generated and gas tracers are injected. The delay in the breakthrough curves is studied. A simple method is used to solve the gas species transport equations in multiphase conditions. This method is based on a formal analogy between the equations of gas transport in a two phase system and the equations of solute tracer transport in water saturated systems. We perform a sensitivity analysis to quantify the relevance of the various transport mechanisms. We find that gas tracer migration is very sensitive to gas tracer solubility, which affects gas tracer transport of both mobile and immobile zones, and shows high sensitivity to diffusion in the gas phase, to heterogeneity and to gas pressure, but the largest sensitivity was observed with respect to injection borehole properties, i.e. borehole volume and water filled fraction.  相似文献   

Analysis of the reliability of a statistical oil spill response model     

Ana J. Abascal  Sonia Castanedo  Raul Medina  Maria Liste 《Marine pollution bulletin》2010,60(11):2099-2110

A statistical oil spill response model is developed and validated by means of actual oil slick observations reported during the Prestige accident and trajectories of drifter buoys. The model is based on the analysis of a database of hypothetical oil spill scenarios simulated by means of a Lagrangian transport model. To carry out the simulations, a re-analysis database consisting of 44-year hindcast dataset of wind and waves and climatologic daily mean surface currents is used. The number of scenarios required to obtain statistically reliable results is investigated, finding that 200 scenarios provide an optimal balance between the accuracy of the results and the computational effort. The reliability of the model was analyzed by comparing the actual data with the numerical results. The agreement found between actual and numerical data shows that the developed statistical oil spill model is a valuable tool to support spill response planning.  相似文献   

Causes of Weather-Related Crashes in Salt Lake County,Utah     

David A. Call  Richard M. Medina  Alan W. Black 《The Professional geographer》2019,71(2):253-264

In 2010, the World Health Organization declared 2011 to 2020 the Decade of Action for Road Safety in response to the enormous toll that roadway crashes take on individuals, communities, and national economies. More than 6.2 million vehicle crashes occurred in the United States in 2015, resulting in around 2.4 million injuries and more than 35,000 fatalities. Motor vehicle crashes in the United States in 2015 had an economic cost of $836 billion, equal to nearly 5 percent of the U.S. gross domestic product. For this study, more than 122,000 crashes occurring in Salt Lake County, Utah, from 2012 to 2016 were analyzed to see how weather conditions affected the number and type of crashes observed. Approximately 12 percent of crashes occurred under “adverse weather conditions.” Weather-related crashes were most likely in the winter season and were very highly correlated with monthly snowfall. Although the greatest number of crashes occurred during evening rush hours, adverse weather-related crashes made up a larger percentage of crashes from 5 to 7 a.m. Although excessive speed was much more likely to be a factor in crashes during adverse weather, such crashes, on average, were less severe. Roadway slope also played a significant role, with slight increases causing more crashes.  相似文献   

Combining point and regular lattice data in geostatistical interpolation     

Jorge Jódar  Gonzalo Sapriza  Christian Herrera  Luis Javier Lambán  Agustín Medina 《Journal of Geographical Systems》2015,17(3):275-296

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Debris-flow susceptibility assessment at regional scale: Validation on an alpine environment   总被引：2，自引：1，他引：1  

Francesco Bregoli  Vicente Medina  Guillaume Chevalier  Marcel Hürlimann  Allen Bateman 《Landslides》2015,12(3):437-454

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