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161.
The structural role played by masonry infills on RC building performances after the 2011 Lorca,Spain, earthquake 总被引:3,自引:3,他引:0
Flavia De Luca Gerardo M. Verderame Fernando Gómez-Martínez Agustín Pérez-García 《Bulletin of Earthquake Engineering》2014,12(5):1999-2026
On May 11, 2011 an earthquake of magnitude 5.1 ( \(M_{w}\) ) struck Murcia region causing nine casualties and damage to buildings and infrastructures. Even if the main characteristics of the event would classify it as a moderate earthquake, the maximum Peak Ground Acceleration (PGA) registered (equal to 0.37 g) exceeded significantly local code provisions in terms of hazard at the site. This high PGA was a result of directivity effects in the near source region. An overview of earthquake characteristics and damage observed is provided. Notwithstanding the lack of proper structural design characterizing building stock in the area, most of the losses were caused by non-structural damage. According to in field observations, it emerges that masonry infills provided additional, “not designed”, strength to reinforced concrete (RC) buildings. Observed damage data, collected after the earthquake, are shown and compared to the results of a simplified approach for nonstructural damage assessment of RC infilled structures (FAST vulnerability approach). The latter comparison provided a fair accordance between observed data and analytical results. 相似文献
162.
Carlo Del Gaudio Paolo Ricci Gerardo M. Verderame Gaetano Manfredi 《Bulletin of Earthquake Engineering》2016,14(10):2643-2678
A damage scenario based on observational data collected in L’Aquila Municipality after the 6th April 2009 earthquake is compared with a predicted damage scenario derived from the application of a simplified analytical method for seismic vulnerability assessment of Reinforced Concrete (RC) buildings at large scale. The observational damage scenario is derived from a database of 131 RC buildings located in the Municipality of L’Aquila, which after the 2009 earthquake were subjected to post-earthquake usability assessment procedure. The simplified analytical approach adopted is based on the Capacity Spectrum Method to evaluate seismic capacity at different Damage States (DSs) based on the displacement capacity of structural and non-structural elements. DSs and the corresponding displacement capacity are defined through the interpretation of the observational-based DSs provided by the European Macroseismic Scale EMS-98. Data predicted by the adopted methodology are in good agreement with the observed damage distribution. The observed damage scenario is also compared with predicted scenarios derived from other methodologies from literature. 相似文献
163.
Gerardo?Carrasco-Nú?ezEmail author Kevin?Righter John?Chesley Lee?Siebert José?Jorge?Aranda-Gómez 《Contributions to Mineralogy and Petrology》2005,150(4):423-440
Nearly contemporaneous eruption of alkaline and calc-alkaline lavas occurred about 900 years BP from El Volcancillo paired vent, located behind the volcanic front in the Mexican Volcanic Belt (MVB). Emission of hawaiite (Toxtlacuaya) was immediately followed by calc-alkaline basalt (Río Naolinco). Hawaiites contain olivine microphenocrysts (Fo67–72), plagioclase (An56–60) phenocrysts, have 4–5 wt% MgO and 49.6–50.9 wt% SiO2. In contrast, calc-alkaline lavas contain plagioclase (An64–72) and olivine phenocrysts (Fo81–84) with spinel inclusions, and have 8–9 wt% MgO and 48.4–49.4 wt% SiO2. The most primitive lavas in the region (Río Naolinco and Cerro Colorado) are not as primitive as parental melts in other arcs, and could represent either (a) variable degrees of melting of a subduction modified, garnet-bearing depleted mantle source, followed by AFC process, or (b) melting of two distinct mantle sources followed by AFC processes. These two hypotheses are evaluated using REE, HFSE, and Sr, Os and Pb isotopic data. The Toxtlacuaya flow and the Y & I lavas can be generated by combined fractional crystallization and assimilation of gabbroic granulite, starting with a parental liquid similar to the Cerro Colorado basalt. Although calc-alkaline and alkaline magmas commonly occur together in other areas of the MVB, evidence for subduction component in El Volcancillo magmas is minimal and limited to <1%, which is a unique feature in this region further from the trench. El Volcancillo lavas were produced from two different magma batches: we surmise that the injection of calc-alkaline magma into an alkaline magma chamber triggered the eruption of hawaiites. Our results suggest that the subalkaline and hawaiitic lavas were formed by different degrees of partial melting of a similar, largely depleted mantle source, followed by later AFC processes. This model is unusual for arcs, where such diversity is usually explained by melting of heterogeneous (enriched and depleted) and subduction-modified mantle. 相似文献
164.
Luciano?TelescaEmail author Marianna?Balasco Gerardo?Colangelo Vincenzo?Lapenna 《Natural Hazards》2005,34(2):177-198
In the present paper we analyse the series of extreme events in geoelectrical signals recorded at the monitoring station Tito located in a seismic area of southern Italy. Applying an objective criterion to estimate the probability of occurrence of extreme events in the time series (Cuomo et al., 1996; Cuomo et al., 1997), we found a correlation between the geoelectrical anomalies and earthquakes in the area monitored during the period of recording. 相似文献
165.
The Zaragoza ignimbrite and two enclosing rhyodacite pumice fall layers were emplaced during the 15 km3 (DRE), ∼0.1 Ma Zaragoza eruption from Los Humeros volcanic centre, 180 km east of Mexico City. The ignimbrite comprises several massive flow-units, the largest of which locally exceeds 20 m in thickness and is regionally traceable. It comprises massive lapilli-ash with vertical elutriation pipes, and has a fine-grained inverse-graded base and a pumice concentration zone at the top. It also exhibits an unusual gradational ‘double’ vertical compositional zonation that is widely traceable. A basal rhyodacitic (67.6–69 wt% SiO2) zone grades up via a mixed zone into a central andesitic (58–62 wt% SiO2) zone, which, in turn, grades up into an upper rhyodacitic (67.6–69 wt% SiO2) zone. Zoning is also defined by vertical variations in lithic clast populations. We infer that pyroclastic fountaining fed initially rhyodacite pumice clasts to a sustained granular fluid-based pyroclastic density current. The composition of the pumice clasts supplied to the current then gradually changed, first to andesite and then back to rhyodacite. Inverse grading at the base of the massive layer may reflect initial waxing flow competence. The pumice concentration at the top of the massive layer is entirely rhyodacitic and was probably deposited during waning stages of the current, when the supply of andesitic pumice clasts had ceased. The return to rhyodacitic composition may have been the result of eruption-conduit modification during collapse of Los Potreros caldera, marked in the ignimbrite by a widespread influx of hydrothermally altered lithic blocks, and/or a decrease in draw-up depth from a compositionally stratified magma chamber as the eruptive mass flux waned. The massive layer of ignimbrite thins locally to less than 2 m, yet it still shows the double zonation. Correlation of the zoning suggests that the thin massive layer is stratigraphically condensed, and aggraded relatively slowly during the same time interval as did the much thicker (≤50 m) massive layer.Editorial responsibility: J McPhie 相似文献
166.
We consider colloid facilitated radionuclide transport by steady groundwater flow in a heterogeneous porous formation. Radionuclide binding on colloids and soil-matrix is assumed to be kinetically/equilibrium controlled. All reactive parameters are regarded as uniform, whereas the hydraulic log-conductivity is modelled as a stationary random space function (RSF). Colloid-enhanced radionuclide transport is studied by means of spatial moments pertaining to both the dissolved and colloid-bounded concentration. The general expressions of spatial moments for a colloid-bounded plume are presented for the first time, and are discussed in order to show the combined impact of sorption processes as well as aquifer heterogeneity upon the plume migration. For the general case, spatial moments are defined by the aid of two characteristic reaction functions which cannot be expressed analytically. By adopting the approximation for the longitudinal fluid trajectory covariance valid for a flow parallel to the formation bedding suggested by Dagan and Cvetkovic [Dagan G, Cvetkovic V. Spatial Moments of Kinetically Sorbing Plume in a Heterogeneous Aquifers. Water Resour Res 1993;29:4053], we obtain closed form solutions. 相似文献
167.
168.
Jos I Saiz Nuria Anadn Javier Cristobo Oscar Garca-Alvarez Gerardo Garca-Castrillo Eduardo Lpez Cruz Palacn Jess S Troncoso Ana Ramos 《海洋学报(英文版)》2013,32(6):47-55
Insular marine biotas are often richer in faunal diversity than those from the open sea in the same geographical region. The existence of particular island effects were tested under polar conditions by comparing infaunal benthic assemblages on Peter I Island with those of similar latitudes in the open ocean at the Bellingshausen Sea and also from the coast of the Antarctic Peninsula. Sampling was carried out aboard the R/V Hespérides during the expedition named BENTART-2003 from 24 January to 3 March 2003. Benthic samples were collected at 18 stations ranging from 90 to 2 044 m depth, using an USNEL-type box corer (BC) dredge. Representatives of 32 higher taxa of invertebrates were found. Univariate and multivariate analyses revealed various patterns in the data. First, significant differences in polychaete abundance were detected between the stations located in the open sea and the remaining sites (island plus mainland sites). Bivalve abundances were also distinct between island and mainland sampling sites. Sediment columns taken from the island seafloor exhibited the highest rate of bioturbation by the infauna. These findings confirm the model that islands develop distinct assemblages characterized by the enhancement of the benthic communities even in cold waters. Several abiotic factors were measured simultaneously at the seafloor and along the water column to investigate faunal distribution patterns. Significant correlations were found between the benthic assemblages and a combination of two environmental variables: "island effect" (measured as a categorical variable) and the redox state of sediments. Richer and more complex benthic assemblages were found in Peter I Island’s sea bottom, whereas the more depauperate bottoms remained in the open sea. 相似文献
169.
In this work, we analyze the various natural and man-made hazards that may affect the Cayman Islands and determine the level
of exposure of Grand Cayman to these events. The magnitude, frequency, and probability of occurrence of the natural and man-made
hazards that may potentially affect the islands are identified and ranked. The more important natural hazard to which the
Cayman Islands are exposed is clearly hurricanes. To a lesser degree, the islands may be occasionally exposed to earthquakes
and tsunamis. Explosions or leaks of the Airport Texaco Fuel Depot and the fuel pipeline at Grand Cayman are the most significant
man-made hazards. The results of the hazard evaluation indicate that there are four areas in Grand Cayman with various levels
of exposure to natural and man-made hazards: The North Sound, Little Sound, and Eastern West Bay (Area 1) show a very high
level of exposure; The Central Mangroves, Central Bodden Town, Central George Town, and the West Bay (Area 2) have high level
of exposure; The Northwestern West Bay, Western Georgetown-Bodden Town, and East End-North Side (Area 3) are under moderate
levels of exposure. The remainder of the island shows low exposure (Area 4). 相似文献