Volcanoes are considered active if they are currently erupting or have erupted within the last 10,000 years. A dormant volcano is not currently erupting but is expected to erupt again in the future. An extinct volcano has not erupted within the past 10,000 years and is not expected to erupt again in the near geologic future.
Smithsonian Global Volcanism Program
USGS Volcano Hazards Program
USGS Hawaiian Volcano Observatory
A slow-moving lava flow from Hawaii’s shield volcanoes can appear deceptively innocuous, but easily destroys everything in its path. When lava enters the ocean, sea water explodes with steam and boiling water. Methane gas explosions can occur, and benches (new land formed from cooling lava) can collapse without warning. Be aware of these dangers when visiting Hawaii’s volcanoes.