Benny Greener age 11of Madison Wisconsin for his question:

What is the biggest volcano ?

On the Island of Hawaii, in Hawaii's National Park, rumbles the massive Mauna Loa   the world's largest volcano. The smoldering crater has thrown up enough lava and molten rocks to form a massive mountain, Such great volcanoes have boon pushing up material from the deep bed of the Pacific Ocean for eons of time. Many of them have become extinct cooled and formed whole chains of islands,

Mauna Loa has a sister peak which is slightly taller  but in over all size: this Mauna Kea cannot compare with the huge bulk of Mauna Loa, The massive base of the world’s biggest volcano rests on the ocean floor 30,000 feet below the surface of the Pacific„ And its smokey top reaches another 13,680 feet above the water.

Smoke and steam can always be seen coming from the chimney of Mauna Loa. The volcano is always active and from time to time it erupts adding to it’s size with new rivers of molten rocks, lava and debris. It has been known to toss this debris for a distance of 2 miles.