The 14th World Conference on Earthquake Engineering

Detailed analysis was conducted for the recorded mainshock across the country during the 21 May 2003 Boumerdes, Algeria earthquake. A remarkable difference has been recorded between neighbour stations. Since local site conditions have a significant effect on the ground motions, and hence on the damage distribution caused by the earthquake, microtremor survey was conducted at several sites of seismic observation stations. In this study, a particular attention is paid to 4 seismic network stations located in the most affected area between Algiers and Boumerdes provinces. Using the microtremor records and the strong motion records from five stations, the effect of soil condition on seismic motion is investigated and the damage distribution caused by this event is explained. The results from this study show that in some stations, the recorded high PGA values were influenced by high-frequency contents. However, in other stations, soil amplification is considered to be responsible for high PGV values. Hence, in order to conduct a further engineering and seismological study, it is highly recommended to conduct an investigation to identify the local soil profile at the seismic stations.