Probabilistic seismic hazard assessment and site analyses of Arusha International Conference Centre (AICC), Arusha, Tanzania

This work presents the evaluation of earthquake resistance of the Arusha International ConferenceCentre (AICC) complex, in Tanzania. The evaluation included probabilistic seismic hazardanalysis (PSHA) and site response analysis. Seismic sources considered to constitute a seismichazard in this study were randomly occurring seismicity located within five tectonic provincesaround the site. For each province the seismic hazard is based on a cursory analysis of earthquakedata from compiled ESARSWG bulletins and temporary deployed networks within the NorthTanzania Divergence (NTD). Bedrock response signal together with the information of materialcharacteristics from boreholes around the AICC site were used in analysis of site response. PSHAresults indicated uniform hazard spectra values of 0.15, 0.2 and 0.27 g for return periods of 475,975 and 2475 years, respectively. The surface ground response results indicated a maximumamplification factor of 3.7 and a spectral response of 4.5 g for a wave period of 0.6 sec thatmatches the natural frequency of the 6-7 storey buildings of the AICC complex. It is thisresonance effect on the buildings that is assumed to have caused intense shaking in the earthquakeof December 5th 2005 from Lake Tanganyika. Keywords: Probabilistic seismic hazard analysis; Arusha International Conference Centre; EastAfrican Rift System; Uniform hazard spectra; Site effect.