ON THE NECESSITY TO ESTABLISH LOCAL SEISMIC HAZARD MAPS FOR URBAN REGIONS

In order to manage urban developments, it is necessary to define the design basis accurately. In urban regions with high earthquake risk, local seismic hazard maps are necessary to properly plan new developments and to ensure that upgrading of existing buildings and infrastructure be carried out properly. The local hazard maps will take into account the following information: - Effects of local faults - Effects of local soils conditions, including the thickness of the soils layers The main usages of this information are: - Definition of design basis for new buildings - Definition of necessary earthquake strengthening of existing buildings - Identification of necessary emergency measures like firewater and access by fire equipment and ambulances - Definition of locations of safe shutdown valves for gas - Identification of muster points for local population to avoid hazards caused by jet fires etc. A case study is presented where particulars of a mayor mega city (Tehran) and a smaller densely populated city (Oslo) are compared. The requirements of both cities are spelled out and suggestions for use of the local seismic hazard maps are presented.