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Shallow vs Structure Estimation for Seismic Site Response Using the Active MASW Method - A Case Study at the Urban Area
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 23rd European Meeting of Environmental and Engineering Geophysics, Sep 2017, Volume 2017, p.1 - 5
Abstract
The multichannel analysis of surface wave method (MASW) was utilized to estimate the soil stiffness at the urban area of Managua, Nicaragua. A total of 24 sites distributed throughout the study area, were sampled using the active walk-away scheme. The results indicates that in most of the sampled sites the elastic bedrock appears shallower than 30 meters. From the soil-class viewpoint, based on the Vs30 criterion, the soils of the area of Managua can be grouped into soil classes C and D, that is equivalent to soil types II and III of the Nicaraguan code. It appears that, the softer soil deposits occur at the western part of the city with a marked strip in north-south direction. The stiffer soils predominate at the central part of the study area that seems to decrease eastwards. Finally, when considering a shallow local earthquake, the calculated amplification function, independently of the depth of the elastic bedrock, shows that the peak ground amplification surpasses the amplification factors suggested in the Nicaraguan Building Code. This may indicate that for shallow local earthquakes the current Nicaraguan Building Code does not reflect the actual soil amplification of the area of Managua.