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Seismic microzonation study of Semarang is still on-going following the recommendations from the Team for Revision of Seismic Hazard Maps of Indonesia 2010 (TRSHMI-2010). The study was performed by carrying one-dimensional site response analysis at 190 locations and implementing Lasem fault as a closest seimic source that significantly influence the hazard of the city. The analysis was performed using two soil deposit models, 30 m and real soil deposit models, to get ground surface peak acceleration (PGA) and amplification factor of PGA. The results obtained using the first model are then compared with the results obtained using the second model. To perform the analysis bedrock elevation and acceleration time histories data are needed. The bedrock elevation was estimated based on 218 single station seismometer measurements. Five different time histories representing different earthquakes with magnitude 6.5 MW and maximum distance 20 km are collected from worldwide historical earthquake records. The results of this study includes the distribution of surface PGA and amplification factor of PGA. The PGA and amplification factor calculated using 30 meter soil deposit model are greater than the same values calculated using real soil deposit model.

The new Indonesian Code for seismic resistance design for building has been issued recently. It follows the concept of Risk-Targeted Maximum Considered Earthquake (MCER). Seismic risk microzonation of Semarang is analyzed using the new concept. Seismic risk microzonation study for hazard mitigation is also performed for the whole city based on deterministic approach, considering the closes distance fault (Lasem Fault). Interpretation of local site effects is performed by carrying one-dimensional ground response analysis. Depth of bedrock is estimated based on single station feedback seismometer measurement. Geotechnical parameters are interpreted from recent and previous measurements. The result of deterministic microzonation study includes the distribution of surface peak ground acceleration (PGA) and spectral acceleration due to Lasem Fault. The obtained results are compared with the distribution of surface PGA and spectral acceleration obtained through new code.