# Preliminary Seismic Hazard Analyses for the Ugandan Region
###### Abstract
Characterizing potential earthquake shaking is not earthquake prediction but quantifying the type and level of shaking that can be expected. One way to help characterize potential earthquake shaking is seismic hazard analysis. Seismic hazard analysis is a quantitative estimation of the level of ground shaking at a particular site [11; 12]. This is not to be confused with seismic risk, which quantifies the potential losses for a given earthquake scenario. The seismic hazard analysis framework generally provides a type of IM that the developer can utilize in further processes such as engineering design or mitigation strategies. With details given later, the seismic hazard \begin{table}
\begin{tabular}{c c c c} \hline
**Date** & **Epicentral Location** & **Magnitude, \(\mathbf{M_{L}}\)** & **Observed Effects** \\ \hline
9 July 1912 & Kitgum near Aswa Shear Zone & 6.0 & Partial destruction of buildings in northern and northwestern Uganda. \\
2 October 1929 & Toro, Western Uganda & 5.9 & Change of water color in the hot springs and earthquake induced landslides. \\
18 March 1945 & Sembabule, 40 km north of Masaka town & 6.0 & Entebbe seismograph put out of order, 5 people dead, and several buildings destroyed [7]. \\
20 March 1966 & Toro, Western Uganda & 6.1 & 160 people passed on, 1300 others injured, and about 7000 buildings damaged. \\
29 March 1966 & Toro, Western Ugandan & 6.6 & 150 people dead and over 1300 injured, as well as property loss worth millions of dollars [8; 9]. \\  & & & 8 people died and demolition of stuff value US561M damage in the western districts of Kasege, Bundibugyo, and Kabarole. The hottest hot spring in Buranga (Sempyaya) geothermal field (98 \% C) emerged. \\
10 September 2016 & East of North western town of Nsunga-Kagera region in Tanzania & 5.7 & 4 people died in Rakaia, 20 were injured, 590 persons were also zaffected, and several buildings were damaged and some collapsed. \\
20 April 2016 & 43 km west of Hoima and 42 km west of southwest of Kigorobya & 4.8 & [10] \\ \hline \end{tabular}
\end{table} 
Table 1: Examples of major earthquakes in Uganda. analysis framework involves firstly selecting a site, the characterization of seismic sources, applying methods to correlate these sources to a preselected IM, and compiling the quantitative results to reach a final IM that represents the seismic hazard at the site. For example, in seismic slope stability problems, a typical set up would require characterizing the load demand as a level of shaking such as PGA. Uganda is also embarking on developing their own nuclear power infrastructure. Lessons from operating countries have shown that for a nuclear power project to be developed, seismic hazard analyses have to be conducted to reduce earthquake-related risks to a potential nuclear facility. It is upon this background that this study intends to perform a preliminary seismic hazard analysis. This preliminary seismic hazard analysis would be conducted using a probabilistic approach with hopes of demonstrating local hazard curves and simplified seismic hazard maps for earthquake resistant design and planning. A review has shown that little literature exists on seismic hazard analyses for the Ugandan region as well as a lack of usable data. Therefore, this study is a vast improvement on previous renditions with a modern approach to the analyses.