Earthquake ground motion estimation using strong-motion records : a review of equations for the estimation of peak ground acceleration and response spectral ordinates

Engineering seismology is the link between earth sciences and engineering. The main input of engineering seismology in engineering design are loading conditions which must satisfy certain conditions regarding their level and frequency of occurrence during the lifetime of a structure. One method for estimating these loading conditions is through equations based on strong ground motion recorded during previous earthquakes. These equations have a handful of independent parameters, such as magnitude and source-to-site distance, and a dependent parameter, such as peak ground acceleration (PGA) or spectral acceleration, and the coefficients in the equation are usually found by regression analysis. This review examines such equations in terms of data selection, accelerogram processing techniques of the strong-motion records used to construct the equations, the characterisation of earthquake source, travel path and local site used and regression techniques employed to find the final equations. It is found that little agreement has been reached in the past 30 years of ground motion estimation relation studies. Workers have chosen their techniques based on the available data, which varies greatly with geographical region. Also it is noted that there is a need to include more independent parameters into ground motion estimation equations if the large uncertainties associated with such equations are to be significantly reduced. The data required to do this is, unfortunately, scarce