The Use of Ambient Noise for Building and Soil Characterisation

Abstract

This chapter deals with diverse problems related to measurements of the ambient noise and their application for determinationof soil or building properties. Although microtremors are studied since the first half of the 20th century, the number ofinves tigations rapidly increased following the article by Nakamura in 1989. In the last two decades a host of methods andprocedures emerged, some of which found their way into the everyday practice of seismologists and engineers dealing with theproblems of site affects and soil-structure interaction.Even though the theoretical background of the H/V ratio technique was initially not completely clear (and controversies stillexist), its simplicity and low cost appealed to many. In his article in this chapter Y. Nakamura revisits the fundamentalassumptions behind the concept of the H/V ratio and presents examples of its use. He clearly advocates the interpretationin terms of body waves, at least around the fundamental frequency of the soil.