Answer :
Geyser is a long narrow, vertical cavity formed in earth crust in the earth crust into which underground water seeps. Here the water column is heated by volcanic heat at where the temperature is above 100C due to the pressure exerted by the water column above. due to the deeper positions, this water is very hot than ground water. therefore bubbles arise and the water pushes up. then the eruption will be started. Due to pressure the water rushes out. thus the geyser continues to spray hot water into air.