The Geysir hot spring is part of the geothermal field in Haukadalur valley in South Iceland, quite close to the entrance to the Kjalvegur road leading to the Highland. It has been active for 10.000 years, although the earliest accounts of hot springs in Haukadalur only date back to 1294. Geysir is a capricious hot spring, sometimes active, sometimes not. Its earliest mention was due to significant changes in the area's landscape following a mighty earthquake. Ever since seismic activities have been carefully documented, and the geothermal field in Haukadalur closely monitored.
Connections between earthquakes and hot spring eruptions
Earthquakes tend to strengthen Geysir. It has had quite a few peeks during the nineteen century, as well as bursts of activities. If we go a bit further back, it had been more or less asleep for ages until the 1896 earthquake. Then it started erupting several times a day again, causing eruptions of up to 60 meters high and lasting for up to an hour. In 1910, Geysir was active every 30 minutes. The spells of activity rarely last more than a few months, and after the action in 1910, it looked as if the mighty Geysir was dead.
Geysir has a history of shutting off and turning on at its own convenience
In 1935 a channel was cut through the silica rim around its vent. The ditch resulted in lowering of the water level and restored Geysir's activity. The channel soon became clogged with silica and eruptions all but ceased. In 1981, the ditch was cleared again. By then, those who had authority over the hot spring realized it could be stimulated – on special occasions – by adding soap to it. Due to environmental concerns, the method was soon abandoned.The last time Geysir displayed its grandeur was following the Icelandic National Day earthquakes in 2000. It spewed its boiling water 122 m high and thus became the highest known geyser in history.
Strokkur has taken over the responsibility of splashing boiling water from the hot spring
Today the other impressive geyser Strokkur has taken the role and responsibility of erupting every ten to fifteen minutes every day and every night of the year. It is one of the most remarkable creature of mother nature in Iceland, almost like it wast designed for tourism. Barely fails or disappoints its hundred of thousands of visitors every year.