# Probabilistic Seismic Hazard Assessment of the Southwestern Region of Saudi Arabia
###### Abstract
Figure 1: Tectonic setting for Saudi Arabia and surrounding areas after [4]. The studied area is marked by an open blue rectangle, and the arrows refer to the relative movements of the tectonic plates. Despite their relative low occurrence, earthquakes are an important phenomenon in Saudi Arabia that needs to be studied due to the possible effects they could have on the population and infrastructures of the area. Due to the region under study's location at the converging point of the Arabian and Nubian tectonic plates, faults like the well-known Najd Fault system are the main sites for seismic activity. Several studies have examined Saudi Arabia's seismic past in an effort to comprehend the frequency, size, and distribution of earthquakes in the area [13; 14; 15; 16; 17]. In Saudi Arabia, seismic building codes (e.g., SBC 201 and 301) are essential for guaranteeing the structural stability of infrastructures and buildings in the event of an earthquake. The seismic design and construction requirements for different building types are discussed in [14] by the seismic rules of the Saudi Building Code. These codes take into consideration the seismic hazard assessments specific to the region, emphasizing the importance of site-specific considerations. The authors of [18] highlight the evolving nature of seismic codes in Saudi Arabia, emphasizing the need for continuous improvement to address emerging challenges. Compliance with these codes is crucial for architects, engineers, and construction professionals to ensure that new constructions and retrofitting of existing structures adhere to the latest seismic safety standards. While research on this topic has been limited, studies such as [12; 19] have made significant contributions in evaluating seismic hazards in this region. Refs. [12; 19] carried out ground-breaking research on the seismic hazard near Saudi Arabia's western coast, illuminating a previously unexplored region. Additionally, numerous research projects have looked into the seismic hazard on the Arabian Peninsula. Early research in the area by the authors of [17] established the foundation for further studies by estimating the peak ground acceleration PGA and the peak ground velocity (PGV) for stiff soils. [PERSON]. [13] improved this research by developing seismic zonation maps for Saudi Arabia, providing essential information for seismic design and risk mitigation strategies. Recently, [PERSON]. [20] introduced a framework for PSHA using the Monte Carlo Approach in Saudi Arabia. Accordingly, further research was needed to refine existing methodologies and improve our ability to assess and mitigate seismic risks effectively. The Gulf nations, particularly Saudi Arabia, are undergoing rapid infrastructure growth with the initiation and execution of extensive national projects. This rapid development calls for critical comprehension, analysis, and evaluation of the seismic hazard in these areas. The expansion of population and development into areas prone to moderate or strong earthquakes has led to an escalating risk of damaged buildings and increased vulnerability. Unchecked urban development often correlates with the construction of structures and facilities susceptible to seismic hazard, primarily due to a lack of awareness about seismic risk in the construction zones. In regions where construction practices are inadequate, even minor seismic events can result in devastating consequences. Given the earthquake activity in the Arabian Shield, the central and southern Red Sea, and the western Gulf of Aden, a comprehensive assessment of seismic hazard in the southwest of Saudi Arabia is critical. In the context of geohazard mitigation and risk management, knowing a region's seismic hazard is essential for preserving the stability of its infrastructure and safeguarding the safety of its citizens.