What are geysers and how are they formed?

A geyser is a natural phenomenon, which is a source that periodically releases hot water and steam under pressure in the form of a fountain. The temperature of the discharged water sometimes reaches 100 degrees. The name of this amazing natural phenomenon was given in honor of the name of one of the oldest known geysers in Iceland – Gelsir.
The formation of geysers is associated with volcanic activity. They arise in places where very close to the earth’s surface there is magma that has not cooled down after an eruption, which releases a large amount of vapor and gases that rise up through accessible channels and cracks. These gases and steam enter the caves filled with underground waters, which have arisen during volcanic eruptions, heat these inputs, mix with them. Further, the heated bottom layer of this water rushes upward and is thrown to the surface through the found channels and cracks. The geyser stops gushing when water runs out in underground caves. But when groundwater fills these caves again and heats up to the required temperature, there will be another eruption.