This volcano formed most of the northern island, and some of the rocks measured from the northeastern side are almost 0.5 million years old.
(This volcano; formed; most of the northern island) (the rocks; measured; from the northeastern side) (some of the rocks; are; almost 0.5 million years old)
This volcano the rocks some of the rocks
formed measured are
most of the northern island
from the northeastern side
almost 0.5 million years old