The European Network on Volcanology established by the EC and ESF early in the ‘90s, led to thorough studies on European Laboratory Volcanoes (4th EC Framework Programme). Monitoring of Mt. Etna and Piton de la Fournaise eruptions since, and the long crisis of Soufriere Hills, Montserrat, have helped elevate the terrestrial, European volcano monitoring capacity to today’s high standards. Conversely, diverse territorial reasons sometimes make effective ground- based monitoring unfeasible at many volcanoes abroad. The EVOSS service will use EO-derived thematic information to observe the whole of European Union, Africa and the Caribbean at high temporal resolution. This strategy presents the potential to react rapidly to any new or unexpected volcanic unrest, to continue observation during years if necessary, and to overcome local structural drawbacks in the RoI.

In the target of EVOSS : EU and Africa volcanoes erupting in historical times

Volcanoes that have undergone at least one documented eruptive unrest in the last 20 years (last event in brackets), are marked in bold. Michael is in the Southern Sandwich Islands. Permanent lava lake activity at Nyiragongo and Erta Ale are considered here as eruptive activity. The CO2 outgassing disaster of lake Nyos (Cameroon 1986, not listed) is not considered a volcanic eruption sensu-stricto. Submarine eruptions – such as those of 1867 at Ferdinandean Bank (Strait of Sicily), 1939-2001 at Kick’em Jenny (off-Grenada, Lesser Antillas), in 2000 off-Terceira (Azores) and in 2004 off-Tristan da Cunha (Southern Atlantic) – are considered out of reach of current EO capacity other than in exceptional cases.

The Antilles are subject to many natural hazards, including large earthquakes, volcanic eruptions, tsunamis, tropical storms, flash floods and landslides. The political context and economic development of the islands is variable and some territories are poor. Hurricanes regularly damage infrastructure and in severe cases, recovery can be slow. In the few islands that have advanced volcano monitoring facilities, central installations and outlying instruments can be temporarily incapacitated and repairs costly. In 2006, Hurricane Dean damaged the Martinique Volcano Observatory, incapacitated some telecommunications networks and cut roads. Montserrat had barely recovered from hurricane Hugo (1984) when Soufriere Hills volcano begun the unrest that culminated in the current eruption of 1995-present.

Individual volcanoes of the island chain only show activity rarely and it is unrealistic to propose dense instrumental ground networks to monitor each volcano. Nevertheless, in the early 20th century, volcanoes in both Martinique and St. Vincent were simultaneously active. In this context, space-borne monitoring can provide a vital tool, complementary to ground-based networks, for example to help detect the first signs of unrest at a poorly monitored edifice, or to maintain effective operational monitoring in the case of an active system where monitoring capacity may be temporarily paralysed.

In Africa, the issue of limited resources for scientifically sophisticated activities such as volcano monitoring is more acute, especially given the strain that already exists in some countries due to serious health crises, for example, or where tele-communications networks may be inadequate. As a result there are many dangerous un-monitored volcanoes in Africa and nearby regions. Space-borne monitoring can be the sole realistic means of performing the crucial task of detecting unrest.

In one recent example, a major rifting event and a small explosive eruption took place in 2005 near Dabbahu volcano in Afar, Ethiopia. No effective ground monitoring network existed, and as confused reports came in from local populations, scientists initially assumed that the much more active Erta Ale volcano, 100 km. to the north, had erupted. This crisis is still ongoing and IPGP is following it by means of a temporary local seismic network and by regularly visualising ground deformation by satellite radar interferometry. With hindsight it was easy to verify with the latter technique, or with space-borne detection of thermal and SO2 anomalies, where the first eruption had occurred. However, it was not possible to do this quickly because of the lack of a convenient service such as EVOSS.

Much more serious problems exist in countries undergoing major political or social unrest, or even military conflict, where disruption to scientific and political chains of interaction or command can be anything from partial to total. This tragic kind of situation was illustrated recently in the Democratic Republic of the Congo, where two volcanoes have been active: Nyiamuragira (2006) and Niyiragongo (2002-present), lava flows from the latter engulfing parts of Goma. Although a geophysical capacity does exist – the Observatory is an End-User in EVOSS Consortium – it is effectively incapacitated by the political and social upheaval.

Even countries such as neighbouring Rwanda that do not have active volcanoes on their territory can be affected because serious volcanic crises can involve events such as the emission of ash and gas clouds that cross the border. Sudan is another country undergoing a refugee crisis that has potentially active volcanoes.

Volcanic Ash threat to Aviation - Volcanic ash clouds can severely damage aircraft flying through them. Ash can clog their sensors, limit the view of the pilots, and severely scratch (“sandblast”) the windows. Ash particles that enter an aircraft's engine can melt (melting point is about 1100ºC), leading to engine failure. The hazard is not limited to the vicinity of the volcano as ash may be transported over large distances. Ash damaged aeroplanes as far away as 1000 km from the erupting Pinatubo volcano in 1991, for example. The only known safe procedure for aeroplanes is to avoid encounters with volcanic ash. This led to the establishment by the International Civil Aviation Organisation (ICAO) of Volcanic Ash Advisory Centres (VAAC), within the framework of the International Airways Volcano Watch (IAVW). The nine VAACs gather information on the possible threat of volcanic ash clouds, forecast their motion, and, if necessary, advise and alert air line and air traffic control organisations.