In pattern A Hawaiian Volcano like Kilauea are created.
they are shield volcanoes.
their eruption is mostly like fissure eruptions.
the pacific hot spot helps in building these volcanoes.
In pattern B Mount St Helen and Rainer like volcanoes are created.
They are stratovolcano.
Their eruption is often violent.
As the pacific plate pushes under the North American plate these volcanoes are built.