The capital city of Ghana, Accra, is located within the most seismically active region of the country.
This study seeks to assess the seismic site condition and amplification based on the shear wave velocity
for the regional capital by the topography as a proxy method. Point slope measurements are extracted
and subjected to seismic site condition correlation of the NEHRP for stable regions. The correlative
seismic site condition within a limiting slope boundary corresponding to a specific soil class is obtained
using regression analysis. We first analyzed available single-point microtremor measurements to know
the fundamental soil frequency for the study area, after which some inversion parameters based on
diffusion assumption were considered concerning the soil frequencies to understand the terrain within
the study area. The inversion outcome could not support the actual representation of soil layers since it
did not include dispersion curves to aid in generating profiles with relatable soil layers. The obtained
Vs30 is then further subjected to the linear site amplification equation for stable regions by Stewart et
al. Scaling ground condition for linear soil response over an average oscillator period of 0.4 to 2 seconds.
An interpolation using the inverse distance weight method was applied to the calculated seismic site
conditions and the site amplification data sets to generate a representative map at a square kilometer area
raster. A comparison will then be made between the global seismic site condition map to understand the
changes and possible similarities. The newly generated map could serve as an improved first-order
approximation of Vs30 for the capital region.
Microtremor, Topographic slope, Seismic site condition (Vs30), Amplification.
Keywords: Microtremor, Topographic slope, Seismic site condition (Vs30), Amplification.