Ambient noise measurements for preliminary microzoning studies in the city of Messina, Sicily

Abstract

On December 28th 1908 the city of Messina was destroyed by one of the most catastrophic Italian earthquakes of the last centuries (Mw=7.1, I = XI) which caused more than 60000 deaths and destruction in many localities of Sicily and Calabria. In this study we present the results of more than 100 seismic ambient noise measurements carried out in the framework of the first massive seismic site response survey performed in the city of Messina. Starting from geological information and historical reports reconstructing the damage scenario of the 1908 event, we have identified several sites particularly interesting for seismic response investigations. This extensive survey allowed us to evaluate the fundamental resonance frequency for each investigated site and to identify the areas prone to site amplification. Measurements have been performed by using 3-component velocimeter, Micromed Tromino, and the collected dataset has been processed by applying the Horizontal-to-Vertical Spectral Ratio technique. For each investigated site we provide the fundamental resonance frequency and a preliminary information on the metamorphic bedrock depth. The massive dataset collected and the results obtained will be useful for the seismic microzonation of the urban territory of Messina.