That has to be on the outer boundary of depths isn’t it?
4 posted on 11/02/2015 10:09:43 AM PST by Sequoyah101
(It feels like we have exchanged our dreams for survival. We just have a few days that don't suck.)
Pretty much so. The subducting slabs do go pretty deep. Average crust thickness Is A mere three miles in the ocean to 20 to 30 miles beneath the continental crusts.