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941.
Earthquake risk assessment of lifelines 总被引:4,自引:0,他引:4
Kyriazis Pitilakis Maria Alexoudi Sotiris Argyroudis Olivier Monge Christophe Martin 《Bulletin of Earthquake Engineering》2006,4(4):365-390
This paper presents the RISK-UE methodology for the seismic risk assessment of utility systems (potable water, waste-water, gas system, telecommunication, electric power) and transportation infrastructures (port, airport, road and railway system). The proposed methodology provides a uniform basis for the reduction of the consequences of lifeline damages in urban areas and an efficient mitigation strategy and prioritization policies for pre-earthquake and post earthquake actions. A detailed inventory for every element at risk together with a reliable seismic hazard assessment, appropriate selection of fragility models, estimation of the “global value” and economical impact of lifeline damages and losses are the main steps of the proposed methodology. The consideration of European distinctive features of lifelines and utility systems in the construction of seismic scenarios and the proposition of fragility curves are among the basic aims of the proposed methodology. Different modules of the methodology were applied in seven pilot cities (Thessaloniki, Catania, Nice, Bucharest, Sofia, Barcelona, Bitola). We present herein few representative examples (case studies) in order to illustrate the methodology and to prove its efficiency. 相似文献
942.
Windsor–Essex County is a major cross-border truck and transportation route, with significant localized industrialization as well as rural and farming areas. Magnetic property measurements (in-field and laboratory susceptibility, frequency-dependent susceptibility, hysteresis properties, thermomagnetic and thermosusceptibility curves, anhysteretic and isothermal magnetizations) were made in order to determine the potential for using such variables to distinguish between natural and anthropogenic pollutants. In-field magnetic susceptibility measured on 324 soil sampling sites on a 0.5–2 km grid spacing through Windsor–Essex County ranged from 3.7 × 10− 6 to 305.2 × 10− 6 SI (average 36.2 ± 35.8 × 10− 6 SI), and showed that high magnetic susceptibility values were obtained on soil sampling sites in and around the cities/towns of Windsor, Harrow, Olinda and Oakland and near the beaches of Point Pelee National Park (PPNP) and Deerbrook, whereas lower susceptibility values were observed in near the towns of Lakeshore and Essex. On this grid spacing, Highway 401 (the major truck route) did not show anomalous susceptibility values; however, closer (1–3 m) sampling on other roads did show anomalously high values, suggesting that the coarser grid spacing may have missed anomalies. Laboratory measurements indicated that the dominant magnetic mineral in the Windsor–Essex County soils is magnetite; however, the grain size is variable. Pseudo-single domain (PSD)–multidomain (MD) magnetite is generally found on beaches and in PPNP, whereas single domain (SD)–PSD magnetite has been found near the City of Windsor and other towns. While certain correlations exist between some anthropogenic activities and the measured magnetic susceptibility and magnetic property values, no overall correlation can be made. A variety of geologic and anthropogenic factors must be considered when interpreting the origin of the magnetic signal in a particular area. 相似文献
943.
The cratonic blocks of South America have been accreted from 2.2 to 1.9 Ga, and all of these blocks have been previously involved in the assembly and breakup of the Paleoproterozoic Atlantica, the Mesoproterozoic to Neoproterozoic Rodinia, and the Neoproterozoic to Phanerozoic West Gondwana continents. Several mineralization phases have sequentially taken place during Atlantica evolution, involving Au, U, Cr, W, and Sn. During Rodinia assembly and breakup and Gondwana formation, the crust-dominated metallogenic processes have been overriding, responsible for several mineral deposits, including Au, Pd, Sn, Ni, Cu, Zn, Mn, Fe, Pb, U, P2O5, Ta, W, Li, Be and precious stones. During Rodinia breakup, epicontinental carbonate-siliciclastic basins were deposited, which host important non-ferrous base metal deposits of Cu–Co and Pb–Zn–Ag in Africa and South America. Isotope Pb–Pb analyses of sulfides from the non-ferrous deposits unambiguously indicate an upper crustal source for the metals. A genetic model for these deposits involves extensional faults driving the circulation of hydrothermal mineralizing fluids from the Archean/Paleoproterozoic basement to the Neoproterozoic sedimentary cover. These relations demonstrate the individuality of metal associations of every sediment-hosted Neoproterozoic base-metal deposit of West Gondwana has been highly influenced by the mineralogical and chemical composition of the underlying igneous and metaigneous rocks. 相似文献
944.
945.
Francisco H.R. Bezerra Mrio K. Takeya Maria O.L. Sousa Aderson F. do Nascimento 《Tectonophysics》2007,430(1-4):27-39
Northeastern Brazil is, within the present knowledge of historical and instrumental seismicity, one the most seismic active areas in intraplate South America. Seismic activity in the region has occurred mainly around the Potiguar basin. This seismicity includes earthquake swarms characterized by instrumentally-recorded events ≤ 5.2 mb and paleoseismic events ≥ 7.0. Our study concentrates in the João Câmara (JC) epicentral area, where an earthquake swarm composed of more than 40,000 aftershocks occurred mainly from 1986 to 1990 along the Samambaia fault; 14 of which had mb > 4.0 and two of which had 5.1 and 5.0 mb. We describe and compare this aftershock sequence with the present-day stress field and the tectonic fabric in an attempt to understand fault geometry and local control of seismogenic faulting. Earthquake data indicate that seismicity decreased steadily from 1986 to 1998. We selected 2,746 epicenters, which provided a high-quality and precise dataset. It indicates that the fault trends 37° azimuth, dips 76°–80° to NW, and forms an alignment 27 km long that cuts across the NNE–SSW-trending ductile Precambrian fabric. The depth of these events ranged from 1 km to 9 km. The fault forms an echelon array of three main left-bend segments: one in the northern and two in the southern part of the fault. A low-seismicity zone, which marks a contractional bend, occurs between the northern and southern segments. Focal mechanisms indicate that the area is under an E–W-oriented compression, which led to strike–slip shear along the Samambaia fault with a small normal component. The fault is at 53° to the maximum compression and is severely misoriented for reactivation under the present-day stress field. The seismicity, however, spatially coincides with a brittle fabric composed of quartz veins and silicified-fault zones. We conclude that the Samambaia fault is a discontinuous and reactivated structure marked at the surface by a well-defined brittle fabric, which is associated with silica-rich fluids. 相似文献
946.
This article argues for a possibly new significance of geographical location in the information age, a significance amounting
to more than mere spatial anchoring, on the one hand, and to less and different than absolute destiny, on the other. Hence,
we show a possible change in the significance of geographical location from destiny in the industrial age to potential opportunity in the information age, a transition which applies to geographical units (i.e. cities, regions) and to individuals. First
we discuss geographical location as destiny in the industrial age for both geographical entities and individuals. Second,
we highlight a transitional period spanning through the 1970s and 1980s during which geographical location lost much of its
absolute nature, becoming more of an anchor. Third, we present a conceptual framework for geographical location possibly turning
into opportunity in the information age, again for both geographical units and individuals. We demonstrate that this potential
opportunity has only partially materialized by individuals in the international use of online shopping, showing that their
adoption is wider in North America, and differentiated in Europe. We further demonstrate a partial dissemination of opportunities
for cities and regions by focusing on FDI. Finally, in the fourth and concluding section, we briefly discuss pertaining policy
issues for the enhancement of locational opportunities. 相似文献
947.
Sonia Maria Barros de Oliveira Paulo Sergio Cardoso da Silva Barbara Paci Mazzilli Deborah Ines Teixeira Favaro Catia Heloisa Saueia 《Applied Geochemistry》2007
In the Cubatão region, southern Brazil, sediments are transported by several rivers from the Serra do Mar Ridge into the Santos estuary. Fertilizer plants have been operating along the margins of one of these rivers (Mogi River) producing a large volume of phosphogypsum, which is stockpiled in nearby areas. Surface sediments of the Mogi River were sampled upstream and downstream in relation to the point where the effluents of the phosphogypsum piles flow into the drainage system. In the vicinity of this point one sediment core was collected. Results show that REE, Ba, Zr and Th concentrations in the non-contaminated sediments are of the same order as those present in the upper continental crust. The contaminated samples present a composition affected by that of the phosphogypsum, marked by a higher concentration of these elements and a stronger degree of REE fractionation. These phosphogypsum characteristics are inherited from the Catalão igneous phosphate ore and were moderately modified by the industrial process of phosphoric acid production. The phosphogypsum signal decreases rapidly downstream, pointing to a limited area of influence of the stacks. The deepest sediments of the core are also free of contamination, representing a time interval prior to the deposition of phosphogypsum wastes on the banks of the estuary. 相似文献
948.
To which extent do wildfires affect runoff production, soil erosion and sediment transport in upland catchments? This transient effect is investigated here by combining data of long term precipitation, sediment yield and wildfire records with a fine resolution spatially distributed modeling approach to flow generation and surface erosion. The model accounts for changes in the structure and properties of soil and vegetation cover by combining the tube-flux approach to topographic watershed partition with a parsimonious parametrization of hydrologic processes. This model is used to predict hydrologic and sediment fluxes for nine small catchments in Saint Gabriel mountains of southern California under control (pre-fire) and altered (post-fire) conditions. Simulation runs using a 45 years record of hourly precipitation show the passage of fire to significantly modify catchment response to storms with a major effect on erosion and flood flows. The probability of occurrence of major floods in the post-fire season is shown to increase up to an order of magnitude under same precipitation conditions. Also, the expected anomaly of sediment yield can increase dramatically the desertification hazard in upland wildfire prone areas. One should further consider the role of firefloods produced by the combined occurrence of wildfires and storms as a fundamental source of non-stationarity in the assessment of hydrologic hazard. 相似文献
949.
Maria Dina Vivarelli 《Celestial Mechanics and Dynamical Astronomy》1983,29(1):45-50
In this note the KS-transformation introduced by Kustaanheimo and Stiefel into Celestial Mechanics is formulated in terms of hypercomplex numbers as the product of a quaternion and its antiinvolute. Therefore it represents a particular morphism of the real algebra of quaternions-having for image a three-dimensional real linear subspace-and also anatural generalization of the Levi-Civita transformation. The quaternion matrix of the product leads to the KS-matrix; the bilinear relation and the two identities which play a central role in the KS-theory are easily derived. A suitable quaternion gauge-transformation is given which leads to the well-known fibration of the four-dimensional space. In addition several geometrical interpretations are brought out. 相似文献
950.
Anna Maria Nobili 《Earth, Moon, and Planets》1978,18(2):203-216
We separate the tidal evolution of a planet-satellite system with zero eccentricity in two phases:phase 1—from the formation of the system to satellite's corotation (satellite's corotation means that its spin angular velocity equals the orbital angular velocity);phase 2—after satellite's corotation.We study the planet-satellite system during phase 1 with Darwin's graphical method and obtain an upper limit to satellite'sQ which discloses whether or not it is corotating. Moreover we obtain some qualitative information about the future evolution of the corotating satellites.The present work does not give any new result for the Earth-Moon case and for the Neptune-Triton case. 相似文献