The last big Great Geysir’s eruption occurred in 2000, when it was revived by an earthquake. In the last decade, however, eruptions have decreased considerably and it is now considered almost inactive.
Earthquakes have been shown to revive the activity of Geysir and records from 1630 show that it erupted violently many times that year. Until 1896 however the hot spring was almost dormant before an earthquake that year caused eruptions to begin again, several times a day.
Here another more impressive erution of the same geyser: