What is the world's largest active volcano by volume?

Mauna Loa is the world's largest active volcano by volume, rising from the seafloor to form more than half of Hawaii's Big Island.

It is a broad shield volcano built by repeated eruptions of fluid, silica-poor basaltic lava. Although its summit is lower than neighboring Mauna Kea, Mauna Loa is far larger overall, with an estimated volume of roughly 18,000 cubic miles. Its submarine flanks extend thousands of meters below sea level.

Mauna Loa has likely been erupting for hundreds of thousands of years. Written records document 34 eruptions since 1843, including major lava flows in 1950, 1984, and 2022. Scientists monitor it closely through the Hawaiian Volcano Observatory.

Kilauea is also highly active and often erupts more frequently, but it is not as large. Mount Everest comparisons can also mislead: Mauna Loa is not Hawaii's highest summit above sea level, but it is the bigger volcano by volume.