Wotten Waven Caldera

The Wotten Waven Caldera is a significant geological formation located in the Roseau Valley of Saint George Parish, Dominica. Identified and named by Demange and colleagues in 1985, the caldera measures approximately 7 km by 4.5 km. It is elongated west-southwest, parallel to a chain of Pelean volcanoes along the southern margin of the Central Graben. The caldera’s margins are partially fault-controlled, and the prominent Micotrin Dome is situated on its northeastern edge.

Geological Significance and Surroundings

Formed by subsidence due to the eruption of the Roseau Tuff, the Wotten Waven Caldera exhibits intense geothermal activity indicative of active volcanic processes beneath the surface. The Roseau Tuff deposits are subdivided into three units:

• Unit 1: Dominated by thick welded ignimbrites channelled between Morne Trois Pitons and Morne Anglais volcanoes, estimated to be older than 46,000 years before the present (B.P.).
• Unit 2: Preceded by Plinian fall activity, these ignimbrites have a widespread extent and are well-exposed in the Goodwill quarry north of Roseau.
• Unit 3: Characterized by pumiceous deposits overlain by extensive block and ash flow deposits, likely originating from the Micotrin Domes, suggesting the eruption concluded with the extrusion of Pelean domes.

Recent volcanic activity includes eruptions dated between 1,160 and 1,020–1,050 years B.P., producing small-volume block and ash flow deposits exposed in the northern part of the caldera. In December 2018, a swarm of volcanic earthquakes emanated from the caldera area, peaking on June 15, 2019, with over 500 events in a 24-hour period.

The caldera’s geothermal activity has given rise to numerous attractions:

• Natural Sulphur Springs: Visitors can relax in therapeutic hot pools at establishments like Screw’s Sulphur Springs, Tia’s Hot Spa, Bongo Baths, and Ti Kwen Glo Cho.
• Geothermal Features: The area is characterized by fumaroles, hot springs, and boiling mud pools.

Surrounding the caldera are the villages of Laudat, Trafalgar, Morne Prosper, Wotten Waven, and the capital city Roseau. The River Blanc borders the area to the north, while mountains such as Morne Anglais, Morne Watt, Morne Nicholas, and Morne Micotrin encircle the caldera.