Shear-induced seismic slope displacement estimates for shallow crustal earthquakes

A new seismic slope displacement procedure is developed, which utilizes 6711 two-component horizontal ground motion recordings from the updated NGA-West2 database. A mixed random variable formulation separates the probability of "zero" displacement (i.e. < 0.5 cm) from the more important distribution of meaningful seismic slope displacement values. A fully coupled, nonlinear seismic slope displacement model captures the important influence of the system's yield coefficient k(y), its initial fundamental period T-s, the ground motion's spectral acceleration at a degraded period of the slope taken as 1.3T(s), and earthquake magnitude as a proxy for duration. An additional term of peak ground velocity PGV, is required to eliminate bias in the estimates for intense (PGV > 60 cm/s), near-fault pulse motions. The procedure can be implemented rigorously within a probabilistic framework or used deterministically to evaluate the shear-induced component of seismic slope displacement.