By developing scientific knowledge and deeper understanding of the geological environment, it is possible to better estimate of seismic hazards. In this paper, by evaluating previous studies, deterministic seismic hazard assessment has been carried out in the Haji-Abad Dam, located in the east of Qaen. Haji-Abad Dam is a dam that is located at a very small distance from the Abiz seismic fault. In spite of this, the evaluation of the previous seismic hazard study, which was carried out before the earthquake occurred on May 10, 1997, estimates the maximum seismic acceleration of about 0.3g. A new evaluation has been made taking into account the Abiz fault in less than 5 km of the site, where the maximum acceleration is about 0.64g. This issue highlights the importance of earthquake hazard review studies for critical structures at specific time periods.