Dangers of Subsea Volcanoes to Mariners

Subsea volcanoes, also known as submarine volcanoes, pose significant dangers to mariners. While many remain hidden beneath the ocean’s surface, their activity can have serious consequences. Here’s how they threaten vessels:

1. Sudden Eruptions

• Submarine volcanoes can erupt with little to no warning, releasing vast amounts of gas, ash, and lava into the water and air.
• Explosive eruptions can cause violent shockwaves, which may damage or even sink ships in the vicinity.

2. Tsunamis

Large underwater eruptions or collapses of volcanic structures can generate tsunamis, which travel rapidly across the ocean and can devastate coastlines.

3. Gas Emissions & Water Displacement

• Volcanic eruptions release gases like carbon dioxide and sulfur dioxide, which can create areas of low-density water.
• This can cause a phenomenon called “ship sinking zones,” where vessels lose buoyancy and sink suddenly due to the gas-saturated water.

4. Floating Pumice Rafts

Eruptions often produce large amounts of lightweight pumice, which float on the ocean’s surface. These can clog water intakes, damage ship propellers, and hinder navigation.

5. Hydrothermal Activity

Heated water and acidic environments near underwater volcanoes can corrode ship hulls and damage sensitive navigation equipment.

6. Ash Clouds & Poor Visibility

Some subsea volcanoes have explosive eruptions that break the surface, producing ash clouds that can reduce visibility and pose a hazard to aircraft as well.

7. Seafloor Changes & Uncharted Hazards

Volcanic activity can rapidly alter the seafloor, creating new islands, reefs, or underwater hazards that don’t appear on nautical charts.

Notable Examples

• Hunga Tonga-Hunga Haʻapai (2022): This submarine volcano near Tonga erupted explosively, sending shockwaves around the world and generating a destructive tsunami.
• Kavachi (Solomon Islands): An active underwater volcano that frequently erupts, posing risks to nearby vessels.
• Kick ’em Jenny (Caribbean): A known submarine volcano that has created dangerous gas bubble zones that can sink ships.

How Mariners Can Stay Safe

• Monitor Reports: Stay updated on volcanic activity through marine advisories and geological surveys.
• Avoid Active Areas: Keep a safe distance from known submarine volcanoes and areas with frequent eruptions.
• Use Satellite & Sonar Data: Advanced navigation tools can help detect changes in the seafloor and potential hazards.
• Be Prepared for Emergencies: Have evacuation and safety plans in place in case of unexpected eruptions or tsunamis.

Subsea volcanoes are hidden dangers of the ocean, but with proper precautions, mariners can navigate safely around these unpredictable natural phenomena.