Probabilistic earthquake hazard Analysis with considering Risk-Based concept (Case study of olefin 14)

numerous seismic hazard analysis studies are conducted annually using probabilistic methods throughout the world and Iran, which are usually different from the initial assumptions of analysis or software used. On the other hand, many researches are presented every year about new methods of earthquake hazard zoning, but so far these studies have not computed earthquake hazard zoning maps for all regions of Iran. Therefore, it is essential to know the modern methods of seismic hazard maps for Iran based on the strategies presented in these sources.

By comparing several national and international standards (ASCE 07 ,UBC-97, API650, IBC, and 038) comparable across Iran and the world, we compare the results of hazard analysis and related parameters in each of these sources. The results were compared with each other, by performing a hazard analysis on a specific site to the strengths and weaknesses of each standard by collecting seismic data from Site 2 of South Pars; Therefore, the basic prerequisites for doing so include reviewing the seismic status and distribution of projected earthquakes, tectonic conditions,active faults at the site, collecting,developing an integrated and comprehensive database of seismic sources within the study area, fault length mechanisms, geometry the maximum disruption and earthquake attributable to each source is.

Using geological and topographic maps, information about seismicity of the area was collected and field visits were carried out in several selected paths in the design range up to approximately 200 km. During field visits, faults in the area were identified and their characteristics determined based on fault maps, seismicity of the study site, seismic parameters and seismic hazard analysis using probabilistic method, maximum acceleration of the strong earth movement and design response spectrum for the surface designated.

The earthquake estimation in ASCE7-5 & 10, IBC, API650 for the return period is 2475 years(Probability of uniform collapse assuming that there is no uncertainty in the collapsing capacity of a structure), but in ASCE7-10 since earthquake estimation is based on the risk concept that leading to the design of structures at risk of collapse is the same(In fact, there is uncertainty in collapsing capacity). The design spectrum of this standard is affected by the risk integral (integration of the hazard curve with the fragility curve), different from the spectrum 2% probability of Exceedance in 50 years, so ASCE7 has a relative advantage over using the new concept in earthquake estimation than other standards.