The Geysir and Strokkur Geothermal Field


The geyser fields in southwestern Iceland comprise two more of the spectacular sights within easy driving distance from the capital of Reykjavik. The principal one is the “Great Geysir”, from the Norse “to gush” or “spout” and therefore the etymological origin for “geyser” in English. The companion and alternate gusher is Strokkur.

Sightseeing in Iceland

The glaciers, hot springs, northern lights and stark solitude once one has left Reykjavik are the real reasons for visiting Iceland, notably for adventurous Europeans. Certainly, one can see the Aurora Borealis in the winter months, from September to March or even April. One need only be near the Artic circle: in Alaska, northern Canada, or northern Scandinavia. As it happens, flight times from Heathrow to Keflavik airport are less than 4 hours, including accounting for the time zone difference. Accessibility is the other big reason for choosing Iceland to trek and see glaciers up close in safety. Greenland is simply too remote and forbidding to cover during a short vacation.
Geological activity explains the danger and austere beauty of Iceland. The “Land of Fire and Ice”, as Iceland is otherwise known, sits astride the Mid-Atlantic Ridge where the North American and Eurasian plates meet. As such, magma is eternally spilling over for thousands of miles under the ocean and deep under Iceland itself. On the other hand, the risk of walking into an ash cloud or active eruption is much less than in Hawaii or Indonesia, where “Hot Spot” activity in addition to plate tectonics, explain a near-continuous procession of catastrophic eruptions. Iceland is strewn with no fewer than 130 active and extinct volcanoes, though just 18 have been known to erupt in recorded history, since about 900 A.D. Still, the 2009 eruption of Eyjafjallajokull did throw vast clouds of ash and lava rocks heated to 1,000 degrees hundreds of meters into the air.

The Geysir Field

All these volcanic activity and deep magma displacement leads to geothermal activity, akin to that of Yellowstone’s “Old Faithful” in the USA (though nowhere near as prolific) and unknown elsewhere in continental Europe.
The more prominent of these is Geysir, at an altitude of 105 to 120 meters (360 feet) above sea level. That means Geysir is near the center of volcanic activity on the island, where the southern lowlands begin to slope up to the rocky interior. The geothermal field is adjacent to Hverasandar or Hvannadalshnjúkur, in the Vatnajökull National Park, and bounded to the West by the eroded little mountain, Laugarfell. The safety risk is low since the Geysir field has been determined to be some distance from active magma fields.
Over time, the geothermal field in Haukadalur may have been heated by magma having intruded into subsurface fissures and thus sustaining high-temperature geothermal activity. Since the Geysir field is spread out over three square kilometers, about 100 meters wide and 500 meters long, geologists observe that the alignment roughly matches the tectonic lines in the area. Since the field is slowly drifting away from the center of volcanic activity, temperatures have diminished considerably. In fact, once-prolific springs such as that in Hvitamelur have gone dry.
ggThe great Geysir, approximately in the northernmost center of the field, is probably the oldest. Twenty meters below the surface is a feeder channel that has risen from subsurface depths of one to two kilometers. The feeder channel is constantly above boiling temperature at 125º C. Hence, Geysir accounts for gushers averaging 1.5 liters per second, while the rest of the field discharges another even dozen liters more per second.
When the pressure from underground tectonic plates become unbearable and a series of earthquakes occur, as often happens, new fissures open up in the underground water tables or aquifers. When that happens, the great Geysir spouts at 6-8 hour intervals.
Though Geysir is an arduous trek inland, Iceland’s rulers have been fascinated by it. Northwest of Geysir is a landmark of three stones (“Konungasteinar” or “king stones” in Icelandic) carved with the initials of three kings who visited the site in modern times: Christian IX in 1874; Frederik VIII in 1907; and Christian X in 1921.


strokkurHappily, the erratic performance of Geysir in contemporary times has been amply offset by Strokkur (“the churn” in Icelandic). Strokkur is a fountain geyser in the geothermal field beside the Hvítá River in Iceland, just east of Reykjavík and near the coast in the southwest of the island. At its peak, Strokkur would surge every 4–8 minutes from 15 to 40 meters high. Currently, the average discharge is 2.5 liters per second, which makes Strokkur more impressive than Geysir.