Seismicity and Seismic Hazards along the East African Rift System (EARS): A Review

The East African Rift System (EARS) is a highly seismically active continental rift characterized by frequent faulting, volcanism, and significant earthquakes that pose substantial risks to infrastructure and populations in the region. Despite numerous seismic hazard assessments, challenges such as limited earthquake data and sparse monitoring networks compromise the reliability of existing studies. Additionally, the absence of seismic design codes in many EARS countries exacerbates the vulnerability of infrastructure to earthquake damage. This review synthesizes seismic hazard research conducted over the past 50 years, with a focus on advancements in probabilistic and deterministic ground motion predictions, as well as micro- and macrozonation techniques aimed at mitigating seismic risks. The findings highlight inconsistencies in hazard estimates, primarily stemming from parameter uncertainties, emphasizing the urgent need for region-specific ground motion models tailored to the unique geological conditions of EARS and the broader African continent. A gap identified is the lack of accurate and harmonized datasets required for effective earthquake modeling. This includes the need for a comprehensive regional earthquake catalog harmonized across borders and homogenized in terms of moment magnitude (Mw). Equally important is the development of a regional database of active faults with associated slip rate information, which is essential for constructing robust earthquake source models. The goal of this review is to enhance the understanding of seismic hazards in EARS and to provide policymakers with actionable insights to support risk mitigation strategies. This is particularly necessary given the rapid population growth and infrastructure development in this region.