than 之后的倒装问题

Tiny quantities of more than thirty rare gases, most of them industrial by-products, threaten to warm the Earth’s atmosphere even more rapidly over the next fifty years than carbon dioxide will.
        

Because the Earth’s crust is more solid there and thus better able to transmit shock waves, an earthquake in the eastern United States will typically devastate an area 100 times greater than will a quake of comparable magnitude occurring in the West.

同样的than比较结构，为何前者不倒装而后者倒装？