While volcanic eruptions do not often cause large humanitarian disasters, they have the potential of causing extreme ones. In the case of volcanic eruption, GDACS alerts mainly utilises source information from authoritative institutions, media and scientific organisations, rather than automated procedures.

Since 1980, volcanic eruptions caused 21800 dead in Colombia (1985), 1746 dead in Cameroon; affected over 1 million people in 1991 in Philippines, over 300 000 in Nicaragua (1992), Ecuador (2006) and Indonesia (1982) (source: CRED/EMDAT). Main volcanic eruptions also triggered the humanitarian emergency response, starting from the large event in Goma with the Nyiragongo in 2002 which required the intervention of the humanitarian community, up to 2016 when the Nyiragongo became active again and because of a complex crisis in the area and breakdown of the local volcano observatory, with space-based observations as the only monitoring solution. Recently, on early-mid 2018, the Volcano de Fuego crisis in Guatemala also required the support of the humanitarian community.

The GDACS information system related to the Volcano status is based on Volcano Ash Advisories (VAAs) and the weekly reports from the Smithsonian Institute.

As a primary source of information, GDACS monitors the VAAs daily issued by the Volcanic Ash Advisory Centres (VAACs). VAAs are automatically stored in the database and provided through the GDACS Alert session when there is a significant increase of the ash cloud emission.

To monitor the volcanic activity, GDACS relies on the weekly reports issued by the Smithsonian Institution (https://volcano.si.edu/reports_weekly.cfm). If the report provides information about a significant increase in the volcanic activity (New Activity/Unrest section), this information is combined to the VAA, in order to provide a comprehensive and updated situation overview.

GDACS issues an alert depending on this information from those two sources:

- GREEN ALERT: significant increase of the ash cloud emission (Alert colour equal to Red or increases from Green to Orange) provided by the VAAC and/or significant increase of the volcanic activity (New Activity/Unrest section of the Smithsonian Institution - Weekly report).

- ORANGE/RED ALERT: manually introduced as soon as a significant volcanic event triggers the attention of the international humanitarian community.

VO GDACS Alert Score:

The GDACS Alert score is currently based only on the wind effect. A GDACS storm surge alert level is also estimated, but this is not yet taken into account in the GDACS alert score. The inclusion of all TC effects in the alert algorithm is under development