This　study　investigates　the　impact　of　aftershocks　on　hazard　assessment　and　disaster　prevention　by　examining　three　main　characteristics　of　strong　ground　motions:　amplitude,　spectrum,　and　duration.　A　total　of　6414　accelerograms　were　compiled　from　26　selected　mainshock-aftershock　events　in　the　Yalong　River　Basin,　China,　Japan,　and　Turkey.　The　aim　is　to　investigate　the　correlation　between　mainshocks　and　aftershocks　using　Copula　theory　and　seven　representative　intensity　measures:　peak　ground　acceleration　(PGA),　cumulative　absolute　velocity　(CAV),　peak　ground　velocity　(PGV),　Arias　intensity,　significant　duration,　mean　frequency　and　predominant　frequency　of　Fourier　amplitude　spectrum.　The　findings　reveal　a　moderate　to　strong　non-linear　correlation　among　the　seven　intensity　measures　of　mainshocks　and　aftershocks.　This　non-linear　correlation　can　be　effectively　captured　using　Gumbel,　Gaussian,　and　t-Copula　functions.　Under　the　conditions　of　the　optimal　Copula　joint　distribution　model　among　the　given　intensity　measures　and　the　mainshock　intensity　measures,　the　Copula　conditional　prediction　model　for　aftershocks　accurately　reflects　the　values　of　aftershock　intensity　measures.　This　approach　demonstrates　the　effectiveness　of　Copula　theory　in　studying　the　correlation　between　mainshock　and　aftershock　intensity　measures.　It　offers　a　novel　method　for　determining　aftershock　intensity　measures　and　investigating　correlations　among　multivariate　random　variables.