Hawaii is located in the middle of the Pacific Plate, not at its boundary of the ring of fire, yet it has many active volcanoes. Why is that?

Volcanoes occur in many locations that are not on the Ring
of Fire around the edge of the Pacific Plate. At any boundary between two or more of the
plates, volcanoes may occur. That's why there are volcanoes in Iceland, for
example.

Volcanoes may also occur at any weak or thin area
of the earth's crust. In the case of the Hawaiian islands, underwater volcanoes have
been erupting for millions of years. As the lava emerges from the underwater volcanic
cones, it hardens and adds to the height of the cones. Because this has been happening
for millions of years in Hawaii's case, the cones have risen above the ocean level and
are now land - the islands of the state, which are still getting taller and larger as
lava continues to emerge and cool.