The Lesser Antilles Volcanic Arc and Subduction Zone: Unlocking the Mysteries

The Lesser Antilles Volcanic Arc and Subduction Zone: Unlocking the Mysteries

Sat, 01/20/2024 - 20:41

The Lesser Antilles Volcanic Arc is a geological formation that shapes the Caribbean Sea. It's a chain of islands from Grenada to Sombrero resulting from the subduction of the North American Plate beneath the Caribbean Plate. It's home to a diverse range of volcanic landforms.

The Lesser Antilles Volcanic Arc

Unlocking the Mysteries

The Lesser Antilles Volcanic Arc is a chain of volcanic islands stretching from the Virgin Islands to Grenada in the eastern Caribbean Sea. It is formed by the subduction of the North American Plate beneath the Caribbean Plate, which creates the volcanoes that make up the islands. This volcanic arc contributes to the shaping of the Caribbean Sea, along with other geological forces.

Geological Framework

Geographically, the Lesser Antilles forms a long arc of islands in the Caribbean Sea, tracing the outer cliff of the Caribbean Plate. This curved chain, approximately 850 kilometers (500 miles) in length, extends from Grenada to Sombrero. However, the island arc bifurcates north of Dominica, with only the western arc remaining active in volcanic activity.

According to the University of the West Indies (UWI) Seismic Centre, the Lesser Antilles region hosts 19 active volcanoes distributed across 11 islands. Each island, whether hosting a single live volcano or multiple potentially active ones, contributes to the dynamic nature of the volcanic arc.

Active Volcanoes in the Region

Numerous islands in the Lesser Antilles region boast live volcanoes, each with its own potential for eruption. Notable active volcanoes include:

  • Dominica: one volcano

  • Grenada: three volcanoes

  • Guadeloupe, Martinique, Montserrat, Nevis, Saba, Saint Kitts, Saint Vincent, Saint Lucia, Sint Eustasius: one volcano each

Among the most active live volcanoes in the region are:

Antilles / Grenada Basin map

Map depicting the Antilles / Grenada Basin.

The Lesser Antilles Subduction Zone

The Lesser Antilles Subduction Zone is a convergent plate boundary that occurs on the seafloor. It involves the subduction of the North American Plate crust beneath the Caribbean Plate. This geological process is known as subduction and occurs when one tectonic plate moves beneath another due to high gravitational potential energy, sinking into the mantle.

The subduction process involved in the Lesser Antilles is oblique subduction, which means that the plates are not only moving directly towards each other, but also slightly sideways. This contributes to the unique tectonic and volcanic activity of the region.

The ongoing subduction of the North American Plate crust under the Caribbean Plate has led to the creation of many volcanic islands. From the Virgin Islands in the north to the islands off the coast of Venezuela in the south, the Lesser Antilles Subduction Zone has left its mark on the Caribbean landscape.

Although the rate of subduction is relatively low, the process is continuous and shapes the region's volcanic and earthquake activity. This subduction-driven geological dance is responsible for the formation of islands and the dynamic nature of the Lesser Antilles Volcanic Arc.

Conclusion

The Lesser Antilles Volcanic Arc, with its active volcanoes, subduction dynamics, and ongoing geological processes, stands as a captivating region that continues to shape the Caribbean landscape. From the individual characteristics of each volcanic island to the overarching impact of subduction, the arc invites exploration into the intricate geological tapestry of the Caribbean Sea.

Diagram of the geological process of subduction

Diagram of the geological process of subduction.