Journal of Geography  & Natural Disasters
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Application of Seismic Refraction Method to Characterize Injibara University Campus Building Site, Injibara, Northwestern Ethiopia

Abraham Mulualem Teshome*

Geophysical investigation using seismic refraction method was conducted for engineering characterization of the foundation conditions of Injibara University buildings construction site located in Injibara town of Amhara Regional State, Northwestern Ethiopia. The principal objective of the research was studying the suitability of the foundation earth materials underlying the site, where Injibara University is established. The seven refraction seismic spreads, seismic velocity models interpretation have provided valuable geotechnical information incorporated with available geologic information in the study area. Interpretation of geophysical data revealed that the subsurface geology of the area is composed of three layers. The topsoil consisted of clay, silt and sand mixtures having a 1-4 m thickness and 255-510 m/s p-wave velocity ranges are mapped over the whole area. The second layer attributed to the highly weathered and fractured vesicular basalt is characterized by 948-1802 m/s p-wave velocity range and revealed somewhat undulating morphology. The depth extent of this layer varies from about 10 m on the North West end and Southeastern parts and to about 27 m around the central part. The third layer occurred in the depth range of 10-27 m is characterized by greater than 2550 m/s average high p-wave velocity and it is due to moderately weathered and fractured basaltic bedrock, which is deeper near to the center of the profiles and gets shallower towards Northwest and Southeastern portions. Besides, analyses of collected data have suggested the possible locations of minor structural discontinuities (maybe local fractures).The geophysical results show that the bedrock is found at shallow depth in the Northwestern and Southeastern part of the study area, whereas in the central part of the survey area the bedrock is found relatively at high depth. Therefore, setting the building foundation is more recommended in the southeastern part of the construction site.