| Most of the earthquake damage is caused by the amplification due to local geological conditions of the seismic waves propagating from the bedrock. A simple and efficient way to characterize the geological conditions is the fundamental natural period of the soil deposit. The use of microtremors is a convenient tool to estimate this period which does not require other geological information. The term microtremor is used to describe any environmentally-induced soil vibrations due to human activities, industries, traffic and noise produced by tides, wind and teleseisms. This work presents a comparison of different experimental techniques to determine the fundamental period of soil deposits. The ambient vibration measurements were undertaken in 134 sites in Mayaguez, Puerto Rico. The site periods were determined with the Nakamura (H/V ratio) technique. Several factors that affect the results were examined to guarantee the stability of the method and an isoperiod map for Mayaguez was prepared. |
