Iceland's geysers: Strokkur, Geysir and the ones nobody mentions

There is something deeply satisfying about the mechanics of a geyser: groundwater is heated by nearby magma beyond boiling point, pressure builds in the vertical channel until it overcomes the weight of the water above, and the result is a column of water and steam fired into the sky with a regularity that no human mechanism can match. The word “geyser” comes from the Old Norse gjósa, to gush, and was the name Icelanders gave to a thermal spring that in the eighteenth century threw water eighty metres into the air in the valley of Haukadalur. That spring is called Geysir, and it is the linguistic ancestor of every geyser on earth.

What happened to the original Geysir

For centuries, Geysir was one of the most spectacular geysers on the planet. Nineteenth-century traveller accounts describe regular eruptions reaching thirty to eighty metres depending on conditions. The Icelandic earthquakes of the twentieth century altered its underground system in ways no one fully understood, reducing its activity to sporadic eruptions and sometimes to years of silence. There is also a documented theory — supported by historical testimony — that the practice of visitors throwing soap into the geyser’s vent to trigger artificial eruptions contributed to damaging the internal plumbing of the chamber. Today Geysir erupts unpredictably: it may fire several times in a day or remain silent for weeks. Visitors to Haukadalur regard it respectfully and then walk the fifty metres to Strokkur.

Strokkur: the mechanics of regularity

Strokkur erupts every six to ten minutes with a punctuality that clocks should envy. The water column reaches twenty to thirty metres, sometimes more, and is preceded by a blue dome that forms in the vent just before the explosion: that dome is what every photographer is waiting to capture, because it lasts less than a second before disappearing under the jet. The technique for getting the shot: stand with the sun behind you, not in front, because water against the light loses the translucent blue sphere that appears in the iconic images. Wait through three or four cycles to understand the rhythm and anticipate the moment.

The Haukadalur area holds, beyond the two main geysers, dozens of thermal springs at different temperatures and colours, fumaroles and small boiling mud pools. The sulphur smell is constant but not as intense as at some other geothermal fields. Walking the marked perimeter for half an hour covers the full range of the system without entering any restricted areas. The ground markers are not decorative: the thermal water can exceed one hundred degrees Celsius.

The geysers nobody mentions

Iceland has several active geothermal fields with phenomena comparable to Haukadalur, without the same volume of coaches in the car park. Deildartunguhver in the west is not a geyser in the strict sense but Europe’s highest-flow hot spring: 180 litres per second at 97°C. The water from this spring is piped directly to the towns of Borgarnes and Akranes — 64 and 34 kilometres away respectively — for district heating, losing almost no temperature in transit. The scale is industrial but the appearance is of a natural cauldron in the middle of a field.

The Námafjall area beside Lake Mývatn in the north holds the most spectacular fumarole and boiling mud fields in Iceland that require no organised excursion: they are accessed directly from Route 1, with a car park and a marked path. The mud pools at Hverir have an appearance and smell that make it difficult to believe the ground underfoot is walkable. Visitors who pass through Mývatn without detouring to Námafjall probably miss the most visceral geothermal experience of their trip.

The Blue Lagoon and what it is not

The Blue Lagoon, near Keflavík airport, is Iceland’s most marketed geothermal experience. It is worth understanding what it is before paying the €90 entrance fee: not a natural phenomenon but the warm effluent from the Svartsengi geothermal power plant, which pumps seawater up from depth to generate electricity. The surplus hot water, rich in silica, accumulates in an artificial lagoon constructed on a lava field. The milky-blue colour comes from silica in suspension. The bathing experience is genuinely good, especially in winter with steam in the air, but knowing what you are visiting seems like basic information that operators rarely supply.

The complete Far Guides Iceland guide includes detailed routes across the whole island, interactive maps and all the practical information you need to plan your Ring Road and beyond.