A favorite stop along the Golden Circle is the highly active Geysir Hot Spring Area with boiling mud pits, exploding geysers and the lively Strokkur which spouts water 30 meters (100 ft) into the air every few minutes. The newly opened Geysir Center offers exhibits and informative presentations year-round.
Geysir Hot Spring Area is one of the most popular tourist stop in Iceland. The geothermal field is believed to have a surface area of approximately 3 km². Most of the springs are aligned along a 100m wide strip of land running in the same direction as the tectonic lines in the area, from south to southwest. The strip is 500m long and culminates near what once was the seat of the lords of Haukadalur. The hot spring area is approximately 100km from Reykjavik, on route 35 or route 37 from Reykjavik through Thingvellir.
Today we find a church there. Here and there, at a considerably shorter distance from the ancient seat than from the hot springs, we find a 20-150 cm thick layer of siliceous sinter, mostly covered by earth, or in some cases even out in the open as the mound at Hvitamelur.
Hvitamelur was once a spouting spring, but it is now absolutely dry. We can still discern the rims of the ancient basin, and the singer safeguards quite a few plant fossils. In other words, hot spring water must have covered large areas from which the geothermal field seems virtually to have moved.
The heart of the geothermal area is now 2 km to the south of the Haukadalur seat, but two little springs have been left behind, Marteinslaug and Gufubadshver. As for the centre of the field, the northernmost springs, such as Geysir itself, are believed to be the oldest.
The temperature of water 20 m down Geysir’s feeder channel is about 125 ºC. It has risen from a depth of 1-2 km. Geysir discharges 1.5 l/s, whereas the entire area discharges 14 l/s. During the dreaded earthquakes that regularly ripple across southern Iceland, deep fractures inch their way into the country as far as to Haukadalur, yet no known damage to property has as yes been caused this far north. After a seismic swarm, the Geysir springs tend to gather new momentum, particularly the spouting springs, each of which seems to try to outrival the other.
Several sources record that after an earthquake, Geysir has spouted impressively at 6-8 hour intervals. The area became active more than 1000 years ago and comprises more than a dozen hot water blow holes. Although the geyser is less active these days, it did lend its name to hot springs all over the world. It was the first geyser described in a printed source and the first known to modern Europeans. The oldest account of Geysir in Haukadalur Valley date back to 1294, earthquakes in southern Iceland caused changes in the geothermal area and created several new hot springs.
Researches in the 19th century showed that the geyser could reach the height of 170 meters! Seismic activity in the area has effect on Geysir and after being dormant for years, Geysir was revived by an earthquake in 2000 and erupted for a couple of times a day for a few years. Now, Geysir is mostly dormant, though other hot springs in the Geysir geothermal area are quite active.
A truly unique experience offered is Geysir or ‘hot spring bread’, where visitors assist a chef to boil eggs outside in a hot spring, and dig up rye bread that has been ‘baking’ underground for 24 hours.The great Geysir is not the only geyser in the Geysir hot spring area. The most active geyser in the area is called Strokkur. It sprouts hot water as high as 30 meters into the air every few minutes or so.
Travellers do not have to pay an entrance fee when visiting the Haukadalur geothermal area. Visitors are encouraged to stay within marked areas and keep away when the geyser erupt, for the water is extremely hot and can burn.
After the turn of the century Geysir grew very listless and in 1916 it ceased to spout entirely. In 1935 a 50 cm deep furrow was carved into the northern rim of the Geysir basin, whereby the spring was revitalised for a few years, but towards the middle of this century it spouted only very rarely. Fortunately, Strokkur was there by its side, spouting gaily enough to satisfy most spectators.
Others waited for a new round of earthquakes to revitalize Geysir. Then something happened in 1981. The furrow that had been carved into Geysir`s rim was scraped clean and enlarged to a depth of 70 cm and a width of 25 cm with the removal of sinter that had accumulated in it. Geysir reacted instantaneously: as its water level dropped, the spring spouted, and continued to do so almost every day until the furrow was covered up and dammed in 1983. Its jets reportedly reached a height of 40-50 m. The furrow was dammed in such a way that it could be reopened. Geysir`s capricious ways have always fascinated its admirers for it never ceases to take them by surprise.