As explained before, there are many interesting features for the volcanoholics to visit in Dominica. I will describe two and keep Champagne bubbles and Tête Chien for a later post.
Should you decide to visit the island I recommend using a small 4WD because the roads are sometimes terrible (even if the Dominica governement has done a lot for road quality lately) and sometimes they are really very steep or muddy. Or both. With real potholes.
The first feature is the Cold Soufriere.
It is located in the north of the island in the Morne aux Diables caldera.
After steep climbing from the coast and getting gorgeous views on nearby Guadeloupe, Les Saintes and Marie Galante you get into the crater.
Accessing it is rather easy as it takes only a few minutes walking on foot from the road. The Terrain is not difficult and there is even a sign post. It is located in a wide crater or caldera, it is difficult to know because of the vegetation.
Note that the northern coast of Dominica is really nearly linear. Some have seen there the results of landslides in the past and consequently some tsunami risk rumors have begun to spread (a bit like the nutters for La Palma).
There were some studies, particularly from french IPGP and Barbadian USWI who conluded that the risk was (of course) extremely low to nearly non existant.
By the way you can check that this type of feature is also present in the adjacent island of Martinica.
But I disgress.
Once on the spot there are several small bubbling pools and ponds, but no visible vapours.
The size of the visible fumaroles area is about 50 x 50 meters. Some small wood bridges let the visitors pass over the bubbling pools. There are probably some other spots, but as the water in the area is corrosive, you tend to stay on the safe areas.
EP Joseph & al (2011) describes the place as a kaipohan feature which means and “area of diffuse cold fluid emissions”. He states that there a strong H2S smell, but we did not smell any strong sulfur odor while in the area.
He gives values of pH around 1-2 (this is very low – “normal pH is 7” and it’s a log scale, but consistent with the gases analyses, with these values you would get painful blisters or damaged skin in a few minutes of contact) and temperatures about 23-28°C.
It is true that the vegetation is damaged.
Also there is some chemical alteration of the volcanic rocks which are clearly visible.
Finally you can get near the bubbling pools and hear their little song.
This pool size is about 30 cm across. The bubbling is energetic
Here are some small videos. Have a look at the rocks alteration by the acid fluids. Note the damaged vegetation.
Let the videos advance to see all the extracts (5 in all)
Soufriere is a small village on the shore of the southern part of the island, facing the Caribbean Sea.
To the south of the island, you also find the Plat Pays volcanic field. In that area there are several fumarolic manifestations. In fact all the south point of the island is a volcanic complex. This is probably one of the most problematic parts of the island with Morne Anglais and Desolation Valley, because they are not far from the Capital City and most populated area, Roseau.
On the highs overlooking The Soufrière village you find a zone of hot pools which have been amenaged to bathe and relax.
If you go higher on the inner slopes of the crater, passing along the cashew nut trees, you reach a fumarolic zone where most of the vegetation has disappeared.
This bing maps link shows the zone from above. Soufrière is on the bottom left, the fumarolic zone on the upper right.
When I refect upon the pictures I’m realizing now that there are maybe the remains of some lava domes. Referring to Lindsay et Al (2003) work there seems to be some dome remains in the crater.
It is of course a wee bit steep and as the water pools and streams are boiling, it is better to watch where you put you feet.
There are several sulfur niches in the fumarolic field. Note the acicular (needle like) crystals. Of course there is some hot water vapour so you’ve got to be careful where you touch.