The hot springs in the Geysir area are of different types.
Geysir and the hot springs to the west and south are normal hot springs, i.e. they emit hot water ascending through narrow channels from deep sources in the crust.
The temperature of the hot springs is up to 100 degrees and some are constantly boiling – if the temperature at depth rises above boiling the hot springs erupt which means that they are geysers.
The word geyser is derived from the name of the famous Geysir.