From what I understand, rebound is fairly rapid at first when the crust itself uncompresses. Then it slows down and gets exponentially slower as the exceedingl

From what I understand, rebound is fairly rapid at first when the crust itself uncompresses. Then it slows down and gets exponentially slower as the exceedingly viscous mantle flows back into the region. I believe that's what's occurring under Finland today, but I'm not sure how fast it ever was at its peak.