Uncertainty Analysis in Dynamic Site and Slope Response // Implements a four-stage pipeline for probabilistic seismic performance analysis of slopes and embankments. The package takes a uniform-hazard spectrum at multiple return periods as input (any source) and produces: (1) synthetic soil profile generation and fundamental period estimation from USCS classification via Ishihara's small-strain shear-modulus model and the inhomogeneous truncated shear-beam theory of Gazetas and Dakoulas; (2) nonlinear site amplification using the NGA- East ergodic site-response models (Stewart et al. (2020) doi:10.1177/8755293019878185 and Hashash et al. (2020) doi:10.1177/8755293019878193, with the 2017 PEER-report generation retained as an option), with inter-period correlation via Baker Jayaram (2008) doi:10.1193/1.2857544; (3) Monte Carlo ensemble of six empirical Newmark sliding-block displacement models (Ambraseys Menu (1988) doi:10.1002/eqe.4290160704, Jibson (2007) doi:10.1016/j.enggeo.2007.01.013, Saygili Rathje (2008) doi:10.1061/(ASCE)1090-0241(2008)134:6(790), Bray Travasarou (2007) doi:10.1061/(ASCE)1090-0241(2007)133:4(381), Bray Macedo (2017) doi:10.1016/j.soildyn.2017.05.024, and the Bray and Macedo shallow-crustal update) with coherent correlated draws; (4) log-log inversion to the performance-based seismic coefficient kmax at user-specified displacement targets. All outputs are 'data.table' objects.