Volcano FAQ

No, volcanoes in the Caribbean are not connected. Volcanoes on individual islands are formed by the same process, i.e. subduction at the plate boundary, but they do not share the same magma chamber, and are not linked by long underground magma conduits. A volcanic eruption on one island, therefore, cannot trigger an eruption on another island.

Geothermal fields or systems are areas of hot springs and steam vents, which form when rainwater seeps into the ground. The water is then heated by hot rock that has itself been heated by underlying magma (molten rock). They do not necessarily represent the vent of a volcano.

Hot springs and fumaroles are not volcanoes. They represent small cracks where hot water and steam escape at the surface. They often occur in volcanic areas, where they can be found in the vent, on the slopes, and in the surrounding countryside, miles away from the volcano! For example, the Sulphur Springs in Saint Lucia is part of the much larger Soufriere Volcanic Centre. It is not the volcano.

No, it does not. The Sulphur Springs area in Saint Lucia, for example, includes over 20 hot springs and steam vents. Contrary to popular belief, these do not act as a “safety valve” to reduce the likelihood of an eruption. The steaming in this area is generated from heated rainwater, which comes from above the Earth. It does not indicate that the volcano is “letting off steam” or reducing pressure. 

Kick ‘em Jenny is the only known ‘live’ (likely to erupt again) submarine volcano in the Caribbean. 

Currently, the volcano is most dangerous for ships and boats since the gases released by Kick ‘em Jenny can lower the density of the water causing them to sink even if it is not erupting. For this reason there is a 2 km exclusion zone around the summit of the Kick ‘em Jenny. Although likely to be minor, tsunamis triggered by underwater eruptions are a potential hazard for neighbouring islands. 

Mud volcanoes are vents/fractures through which natural gas such as methane exit, entraining a slurry of mud and sand with it, which they will spew at the surface. Mud volcanoes are not real volcanoes and are not as hazardous as real volcanoes since they can only emit warm mud and only very locally (a few hundred meters around them). Mud volcanoes are generally encountered in areas where natural gas is present. “Real” volcanoes are different. They erupt when magma (i.e., molten rocks) reach the surface and become lava. 

Earthquakes are not necessarily linked to volcanic activity. Some earthquakes are due to tectonic activity (plates shifting), hence not related to volcanoes, while some others are due to magma trying to find its way up a volcano (volcanic earthquakes). Volcanic earthquake are generally indicative of an increase of volcanic activity but don’ necessarily lead to an eruption. Tectonic earthquakes can “shake” a volcano and can potentially help triggering an eruption. However, they can also potentially stop an eruption. No direct links between tectonic earthquake activity and eruptions in the Eastern Caribbean have been found so far. 

It is rather unlikely that geothermal exploration can trigger an eruption. However, geothermal energy extraction can modify the surroundings of the exploration sites (e.g., ground subsidence). While these changes will tend to be relatively shallow (compared with the deep roots of a volcano), exploration must be carefully monitored when located close to an active volcano. 

The type of lava flow depends on the chemical composition of the lava. Lava with low silica content are less viscous (i.e., more “fluid”) and can flow freely downslope as in Hawai’i. Lava with higher silica content are more viscous (i.e., “stiffer”) and cannot flow as freely. They will tend to accumulate close to the vent (e.g., crater) and form lava dome. Our volcanoes in the region tend to produce viscous lava flows (e.g., dome at Soufriere Hills Volcano in Montserrat). But some have produced lava which are fluid enough to produce long distance traveling lava flows, as in St Vincent.

It is unlikely that an eruption will occur without warning. Volcanic eruptions in the Eastern Caribbean are usually preceded by recognizable symptoms, such as small earthquakes, changes in gas chemistry, and/or ground deformation (swelling of the mountain) long before an eruption occurs. The Seismic Research Centre operates a monitoring system which should enable scientists to provide sufficient warning to the authorities prior to an eruption so that appropriate action can be taken.

Volcanoes are caused by processes beneath the surface of the Earth and the factors which may trigger eruptions are totally unconnected to the atmospheric processes which cause changes in weather. Heat waves, overcast conditions at the summit or any other weather phenomena do not indicate anything about the state of the volcano. However, heavy rains during an eruption may trigger mudflows (lahars) and lightening can occur from eruption columns. 

The term “soufriere” comes from the French “soufre”, which means sulphur. In many volcanic areas, sulphur is naturally deposited at the surface by the volcanic gases and has traditionally been extracted and used by people. A “soufriere” is by definition such a place where sulphur is naturally deposited and is often associated with a volcano (e.g., Soufriere Hills Volcano, in Montserrat or the town Soufriere in Dominica). 

A volcano is considered active (i.e., “live”) when signs of activity can still be detected. These signs can be occasional volcanic seismic activity, gas emitted on an around the volcano, ground deformation. Apart from the occurrence of gas vents, most of these signs are generally only detectable with specialized monitoring equipment (e.g., seismometers, GPS).