4:30 PM Thursday Update: The ODM and UWI SRC have determined that the recent activity in the Soufriere area is likely the result of a landslide in the area, followed by subsequent re-settling of the near surface hydrothermal activity with associated strong steam degassing.
The full release is as follows:
“The Soufriere area is noted for its hydrothermal activity, which is usually manifested as surface degassing, primarily of steam. The volcanic origin of the soil, in addition to the hydrothermal weathering in the area, has created conditions favouring landslides.
A visit to the area earlier today showed nothing unusual. Thus, there appears to be no cause for panic at this point.
The ODM took photos and drone footage of the area which were provided to the Seismic Research Centre (SRC).
Based on information supplied by the ODM, the SRC team determined that the recent activity in the Soufriere area is likely the result of a landslide in the area, followed by subsequent re-settling of the near surface hydrothermal activity with associated strong steam degassing.
There have been no associated volcanic earthquakes recorded in the area by the SRC network on the island. The SRC therefore believes that a change in volcanic activity has not contributed to this event.
It is possible that the area may still be unstable and additional landslides may occur with continued steam degassing.
The ODM and SRC will continue to monitor the area. Public access to the area should be limited.“
On Wednesday evening, residents of Soufriere, Dominica began reporting emissions from the northwestern hills, towards the Morne Plat Pays Volcano. One reaction on social media stated, “a loud noise was heard, leaving what appeared to be smoke.”
At 7:00 PM Wednesday 16th September 2020, the Office of Disaster Management of Dominica (ODM) issued the following release:
“The Office of Disaster Management (ODM) has received reports of emissions being observed in the Soufrière area in the south of Dominica. This report is being investigated and the public will be updated.”
“The ODM is in contact with the Seismic Research Centre UWI, Trinidad who is responsible for monitoring seismic activity on Dominica.”
“At this time, the ODM is advising the public to stay clear of the area until further notice.”
Dominica is one of the youngest islands in the Eastern Caribbean, formed through volcanism that remains active. Over the millions of years, a chain of nine young volcanic centers forms the backbone of Dominica. These include Morne Plat Pays, Morne Anglais, Petite Savane, Grand Soufriere, Morne Watt, Watt Woven Caldera, and Morne Trois Pitons across Southern Dominica. Morne Diablotins exists further north and Morne aux Diables in the far north of the island.
Dominica’s Volcanic Unrest
Volcanic unrest is considered a period where there is increased seismic activity associated with a (or many) volcanoes. In Dominica’s case, this is Southern Dominica.
According to the University of the West Indies Seismic Research Centre (UWI SRC), this period of unrest began in December 2018 and continues to this day. Since then, UWI SRC has recorded daily earthquakes on the island. They also noted that most of these earthquakes are usually very small in magnitude, and it is unlikely inhabitants of the island may experience shaking.
Professor Richard Robertson, the previous director of UWI SRC, also explained that “there are occasions where the magnitude may be big enough or the quakes are shallow enough” for people to feel shaking.
During this overall unrest period, there have also been bursts of earthquakes or earthquake swarms where more frequent volcanic earthquakes have been recorded. As of September 2019, the UWI SRC has recorded swarms during December 2018, February 2019, and June 2019 where some events were reported felt.
The UWI SRC continues to emphasize that this unrest period does not necessarily mean that an eruption will occur but larger magnitude earthquakes can occur and so the public should remain vigilant.
You can watch Professor Robertson’s full explainer from the UWI SRC below.
What is causing this unrest?
Dominica is a volcanic island with several active volcanoes. This type of activity is expected where active volcanoes exist, as we have seen in other parts of the Caribbean (Kick’em Jenny, Montserrat). Some of the reasons volcanologists know Dominica has active and live volcanoes are the number of fumaroles (where is an opening near or in a volcano where hot, sulfurous gases emerge), the vast area of young rocks, and seismic activity that become elevated from time to time.
What is the UWI SRC doing in response?
Since the start of the unrest period, the UWI SRC has increased monitoring across Dominica by installing more seismic and GPS stations and collecting gas and condensates from sulphur springs. UWI SRC continues to provide frequent updates to the Dominican government. They have also advised on plans and protocols in case of further escalation.
What does this mean for us (in T&T) and the Dominican people?
For the public in T&T, this will be nothing more than a news story as volcanism in Dominica does not impact our seismic events in the T&T region. Note that it also has no relation to our mud volcanoes across the southern half of Trinidad, as mud volcanism is a completely different system.
For the people of Dominica, listen to official sources of information (such as the ODM or UWI SRC) and educate yourself on what to do in case of something escalating. According to the UWI SRC, given past activity (as of September 2019), it is likely that this unrest may go back to background levels, and nothing will happen. However, the SRC also mentioned in 2019 the small possibility that it could escalate to eruptive activity as records have shown steam explosions, or sometimes more intense.
This is a developing story and will be updated.