Surtsey Island: Watching a New Volcanic Island Form in Real Time

An Island That Did Not Exist Before November 14, 1963

At approximately 7:15 a.m. on November 14, 1963, a cook aboard the Icelandic fishing vessel Ísleifur II, working southwest of the Vestmannaeyjar (Westman Islands) archipelago off Iceland's southern coast, noticed black smoke rising from the sea surface. The captain initially suspected a ship on fire. What he was witnessing was the emergence of a new volcanic island — the first stages of what would become Surtsey, named for Surtur, the Norse fire giant. Within days, the eruption had built a visible land mass above the Atlantic surface. Within months, it had produced an island roughly two kilometers long.

Surtsey's birth, continuing eruption, and subsequent colonization by life offered scientists an extraordinary natural laboratory — a landmass of known age, built of known materials, with no prior biological history, rising from a well-studied ocean. The island became one of the most intensively studied geological and ecological sites on Earth and was designated a UNESCO World Heritage Site in 2008.

The Eruption: Phases and Mechanics

The eruption that created Surtsey began on the floor of the North Atlantic at a depth of approximately 130 meters, where the mid-Atlantic Ridge volcanic system extends beneath Iceland's coastal shelf. Over several days, material accumulated until the growing pile broke the ocean surface on November 14.

The earliest eruptive phase — termed a Surtseyan eruption — was characterized by violent phreatomagmatic explosions: the interaction of hot magma with cold seawater produced enormous quantities of steam and fragmented lava, building a cone of tephra (loose volcanic fragments) rather than solid lava flows. These early tephra deposits were unconsolidated and highly susceptible to wave erosion.

The transition from explosive phreatomagmatic activity to effusive lava flows was scientifically significant — it occurred when lava flows reached the shoreline and the advancing lava sealed the vent area from seawater infiltration. The change was rapid and dramatic: within days of lava reaching the shore, the violent steam explosions ceased and relatively quiet lava lake activity replaced them. This transition gave Surtsey its hard basaltic lava cap that has resisted wave erosion far better than the early tephra deposits.

Erosion and the Island's Changing Size

At its maximum extent in 1967, Surtsey covered approximately 2.7 square kilometers. Wave erosion has reduced it continuously since the eruption ended. The tephra deposits on the island's flanks erode quickly; the harder lava-capped central portion resists more effectively.

• By 2012, Surtsey had shrunk to approximately 1.3 km², less than half its maximum extent
• Calculations suggest the island will continue eroding; some projections estimate the island could disappear below sea level within 100 years, though volcanic activity could rebuild it
• Hydrothermal activity within the island has also altered the rock through chemical processes, partially consolidating tephra into more erosion-resistant palagonite

Geologists use Surtsey's erosion as a model for understanding how ancient volcanic islands elsewhere in the Atlantic — the Canary Islands, Azores, and older seamounts — have changed over geological time.

Life Colonizes from Zero

Biologists were on Surtsey almost immediately after the eruption ended, establishing monitoring protocols that have continued for over 60 years. The island offered something unique: a sterile substrate of known age, allowing researchers to track precisely when and how each species arrived.

Colonization has proceeded in a documented sequence:

• 1965: First vascular plant found — a sea rocket (Cakile arctica) on the beach; did not persist
• 1965: First mosses and bacteria documented
• 1970: First successful nesting seabird colony (northern fulmar)
• 1986: First documented earthworms
• 2004: First documented Atlantic puffin nesting
• By 2022: Over 89 vascular plant species, 335 invertebrate species, 12+ seabird species nesting regularly

Seabirds have been critical accelerators of plant colonization. Nesting colonies deposit nutrients (guano) that dramatically enrich soil and enable plant species that could not otherwise establish. The northern fulmar colony's establishment preceded measurable acceleration in plant diversity.

Access Restrictions and Scientific Significance

Access to Surtsey is strictly controlled by the Surtsey Research Society and Icelandic government authorities. Only scientists with approved research projects are permitted to land on the island, and visits are kept minimal to avoid contaminating the colonization record with introduced species. A small research hut provides basic shelter for visiting scientists.

The restricted access policy has created one of the cleanest long-term biological monitoring datasets in ecology — a rare situation where human influence is nearly zero and baseline conditions are thoroughly documented. Surtsey's research has directly informed conservation biology, island biogeography, and volcanic geology on a global scale.