Scientists divide volcanoes into three cat
egories - extinct (considered as no threat to erupt again), dormant (inactive, but subject to possible future eruptions) and active (currently or recently erupting). The volcanoes that formed the island
s of Kauai
and Oahu are classified as extinct; Haleakala on Maui is classified as dormant; and, Mauna Kea on the Big Island
has been in a constant state of eruption since the early 1980s.