Browsing by Author "Odumeru, Gladys Titilayo"

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    Vulnerability assessment of boreholes drilling along fault lines and their impacts on earthquakes/ tremors in Nigeria
    (Department of Geography, Faculty of Social Sciences, Obafemi Awolowo Univeristy, 2023) Odumeru, Gladys Titilayo
    The study analyzed spatio-temporal clustering of past earthquake/tremor events, and examined borehole drilling with other geophysical factors and their impacts on earthquake/tremor occurrences. Finally, the study modeled an earth vulnerability map of the study area. These were with a view to determining the effect of indiscriminate borehole drilling along fault lines which can stimulate an earth movement. The study made use of mainly secondary data. The data include the magnitude of past earthquake/tremor events (1933-2018), geospatial data such as DEM (Digital Elevation Map), soil/geology maps and tectonic data from the 1m SLAR (Side Looking Aerial Radar) Aeromagnetic Lineament Map of Nigeria were used for the study. Data were analyzed using geospatial techniques, descriptive and inferential statistics (multiple regressions). The result of the Anselin Local Moran’s I and Getis–Ord Gi* Pattern Analysis showed a Spatio-temporal clustering of Earthquake/Tremor events in Ogun, Oyo, Kaduna states and the Federal Capital Territory at a global and local level, where borehole drilling, mining, and quarrying are primed, with zscores of 1.76, 1.80, 1.64, and -2.56 and p-values<1.73, 0.05, 0.03, 0.045, 0.0008, and 0.04, at 0.05 significant level and at 95% confidence interval, while, Ogun and Bayelsa states were identified as earthquake/tremor hotspots where borehole drilling and oil well drilling are respectively predominant at 90% and 99% confidence interval. The results also showed that drilling and quarrying/mining had a statistically significant effect on the magnitude of past earthquake/tremors with p-values< 0.02 and 0.04 respectively at 0.05 significant level and 95% confidence interval. The modeled earthquake/tremor hazard/vulnerability map using Analytical Hierarchal Processing (AHP) and Pairwise Comparism Matrixes (PCM) with Eigen 18 values of 0.62, 0.22, 0.088, 0.042, 0.027 assigned on the Lineament density, geology, soil, elevation and magnitudes respectively were finally processed on a weighted overlay tool, ranked on a likert scale ranging from: Very high hazard/vulnerability (7), high hazard/vulnerability (5), moderate hazard/vulnerability (3), low hazard/vulnerability (2) and very low hazard/vulnerability (1) levels. The study concluded that indiscriminate borehole drilling along fault lines could stimulate an earth movement within the study area.