In this map, the white colored in line is supposed to be Subduction Zones and the black dotted lines are supposed to be Sea Floor Spreading areas:
Source Map NOAA
So, are they really subduction zones though? I think they probably are. However, to me, it looks as though there is much more crustal spreading going on than there is subduction going on, a lot more. Perhaps that's due to the expansion of Earth's Iron Core as it cools.
Source: Expanding Earth Outline (?)
