The Vanuatu archipelago has 16 volcanoes. Local, regional and central government authorities, plus the aviation and tourism industries, media and the public, need to know if there are any changes to the volcanoes' behaviour.
The overall activity is quantified by setting a Volcanic Alert Level from 0 to 5 for each volcano.
Responding agencies in Vanuatu are notified whenever the alert level changes, and they use it to determine the type and scope of their responses.
Volcanic Alert Bulletins are issued whenever there is a significant change in volcanic activity in Vanuatu.