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Earthquake is a sudden release of energy due to faults. Natural calamities like earthquakes can neither be predicted nor prevented. However, the severity of the damages can be minimized by development of proper infrastructure which includes microzonation studies, appropriate construction procedures and earthquake resistant designs. The earthquake damaging effect depends on the source, path and site conditions. The earthquake ground motion is affected by topography (slope, hill, valley, canyon, ridge and basin effects), groundwater and surface hydrology. The seismic hazard damages are ground shaking, structural damage, retaining structure failures and lifeline hazards. The medium to large earthquake magnitude (< 6) reported in Ethiopia are controlled by the main Ethiopian rift System. The spatial and temporal variation of earthquake ground motion should be addressed using the following systematic methodology. The general approaches used to analyze damage of earthquake ground motions are probabilistic seismic hazard assessment (PSHA), deterministic seismic hazard assessment (DSHA) and dynamic site response analysis. PSHA considers all the scenarios of magnitude, distance and site conditions to estimate the intensity of ground motion distribution. Conversely, DSHA taken into account the worst case scenarios or maximum credible earthquake to estimate the intensity of seismic ground motion distribution. Furthermore, to design critical infrastructures, DSHA is more valuable than PSHA. The DSHA and PSHA ground motion distributions are estimated as a function of earthquake magnitude and distance using ground motion prediction equations (GMPEs) at top of the bedrock. Site response analysis performed to estimate the ground motion distributions at ground surface using dynamic properties of the soils such as shear wave velocity, density, modulus reduction, and material damping curves. Seismic hazard evaluation of Ethiopia shown that (i) amplification is occurred in the main Ethiopian Rift due to thick soil, (ii) the probability of earthquake recurrence due to active fault sources. The situation of active fault is oriented in the N-S direction. Ethiopia is involved in huge infrastructural development (including roads, industrial parks and railways), increasing population and agricultural activity in the main Ethiopian Rift system. In this activity, socio-economic development, earthquake and earthquake-generated ground failures need to be given attention in order to reduce losses from seismic hazards and create safe geo-environment.

The study area is located in one of the most earthquake prone regions in southern Ethiopia, which is characterized by small-to-intermediate earthquake occurrences causing damage to buildings. Predicting liquefaction hazard potential and local site effects are imperative to manage earthquake hazard and reduce the damage to buildings and loss of lives. The objectives of this work were to perform the equivalent linear response analysis (ELA) and shear wave velocity (Vs.)-based liquefaction hazard analysis and classify the site into different seismic site classes based on the European and American codes. The SPT-N and Vs.30 values showed the site falls in the C and D classes based on the NEHRP (2015) code but falls in the B and C classes based on the EC8 (2003) code. The susceptibility of liquefaction was evaluated using grain size analysis curves. Moreover, peak ground acceleration (PGA), spectral acceleration (SA), and maximum strain (%), which are very critical to understanding the local site effects, were estimated by the DeepsoilV.7 program. The cyclic stress ratio and cyclic resistance ratio were used to calculate the factor of safety (FS). A liquefaction potential index (LPI), probability of liquefaction (PL), and probability of liquefaction induced ground failure (PG) were used to assess the probability of liquefaction. The peak ground acceleration (g) values ranged from 0.166 to 0.281 g, whereas spectral acceleration (g) was found to be high at 0.1–1s. The liquefaction susceptibility screening criteria revealed that the study area is highly susceptible to liquefaction. FS is &lt; 1 for a liquefied site, but FS is &gt; 1 for non-liquefied sites. In comparison to non-liquefied sites, the liquefaction forecast site has a liquefaction potential index value of 0–54.16, very likely high PL, and high PG. The findings will be helpful in the design of structures and in solving practical challenges in earthquake engineering.

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