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An indication of the soil topmost layer response in Quito (Ecuador) using noise H/V spectral ratio 总被引：1，自引：0，他引：1
P. Guguen J. -L. Chatelain B. Guillier H. Yepes 《Soil Dynamics and Earthquake Engineering》2000,19(2):1073
H/V noise spectral ratio (HVSR), standard spectral ratio (SSR), and receiver functions (RF) techniques have been used in the Quito (Ecuador) urban area to estimate the frequency dependence of soil response. Two amplified frequencies obtained by the HVSR method appear on about 60 sites. Taking into account the most amplified frequency rather than considering only the first amplified frequency, generally associated with the fundamental frequency, we find that iso-frequency curves tightly fit the surface geology. The second amplified frequency is interpreted as the fundamental frequency of the soft thin topmost layer, which in some cases amplifies the surface ground motion more than the rest of the soil column. This hypothesis is further supported by the results provided from the SSR and RF studies at a station located on top of a solid waste landfill, and by a study of known thickness of a waste landfill, using the HVSR method. 相似文献
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Roy H. Ryder 《The Professional geographer》2004,56(4):488-502
It is generally assumed that older mansions in the elite residential sector of Latin American cities filter down to the middle classes once their residents migrate to modern suburban homes. Five land use maps compiled between 1975 and 1999 show that the elite residential sector of Quito (Mariscal Sucre) experienced a much more complex fate. Diffusion of nonresidential land uses from the city center and its associated spine transformed the residential neighborhood into a vibrant upper‐scale business district. Sophisticated businesses subsequently moved on to modern suburban facilities, but Mariscal Sucre became a major hub for business, nocturnal entertainment, and tourism. Diversification of land use in Mariscal Sucre confirms the Crowley hypothesis of complexity in Latin American urban land use patterns ( Crowley 1995 ). 相似文献
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Situated at the foot of the Pichincha volcano, the city of Quito is frequently subjected to hydroclimatic hazards. In 1995 an 11·2 km2 watershed, located in the vicinity of the city, was equipped with eight rain gauges and two flow gauges to better understand the local rainfall/runoff transformation processes. Rainfall simulation experiments were carried out on more than 40 one‐square‐metre plots to measure infiltration point‐processes. The high density of measurement devices allowed us to identify the origin and nature of the various contributions to runoff for the different physiographic units of the watershed: urban area from an altitude of 2800 to 3200 m; farmland, pasture and forested land, and finally páramo above 3900 m. Runoff occurs mainly in the lower part of the basin and is caused by urbanization; however, the natural soils of this area can also produce Hortonian runoff, which is predominant in a few events. This contribution can be studied through rainfall simulation experiments. In the upper natural zone, the younger and more permeable soils generate less runoff on the slopes. However, almost permanently saturated contributing areas, which are located in the bottom of the quebradas, may generate flood events, the size of which depends on the extent of the area concerned. Variations in the runoff coefficients are related first to the baseflow and second to the amount of rainfall in the previous 24 h. This analysis, which underlines the complexity of a small, peri‐urban, volcanic catchment, is a necessary preliminary to runoff modelling in an area where very few experiments have been carried out on small catchments. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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Political and scientific uncertainties in volcanic risk management: The yellow alert in Quito in October 1998 总被引：1，自引：0，他引：1
Volcanic risk management involves volcanologists, civil authorities and the affected population. The paper reports on one
`yellow alert' in Quito in 1998. It describes the scientific context, the political announcement and the decision-making process
that preceded, as well as the social perception of the volcanic crisis.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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