PROBABILISTIC SEISMIC HAZARD ANALYSIS OF SOUTHWESTERN NIGERIA

Abstract

For about ten decades, the seismic record of Nigeria has shown the occurrence of several
magnitudes of earthquakes. This is contrary to the belief of some people in time past that Nigeria is aseismic.
In number and in size, most of the witnessed earthquakes in Nigeria are found to occur in her South-Western
region. Researchers have also begun to warn recently that some regions of Nigeria should prepare for
devastating earthquakes in years to come. Hence this paper aimed at the probabilistic seismic hazard analysis
of the South-Western region of Nigeria using the available historical and instrumentally recorded data. The
Gutenberg-Richter (G-R) recurrence law was used to assess the seismicity parameters and to generate a model
for calculating the mean annual rate of exceedance and to forecast probable future earthquake occurrence in
the South-West. The findings of this assessment established that the South-West region of Nigeria is likely to
experience earthquake magnitude as high as 7.2 in the year 2028 with a probability of 36.79%. Hence, this
work enlightens on the extent of probable future earthquake magnitude in South-Western Nigeria and it is
recommended that the government of Nigeria and inclined agencies begin to look into earthquake in this region.