The Old Faithful Geyser in Calistoga, California, puts on an exciting show for tourists. Each time it erupts, steam and hot water shoot over 60 feet into the air. The water comes from an underground river. When water from this river flows over hot magma, the water becomes boiling
hot. Forced through cracks in the earth's rocky crust, water and steam surge out of the ground.
Old Faithful In California is one of the world's three "old faithful" geysers, which erupt at regular intervals. Its Intervals are typically
30 minutes apart. Some researchers believe that changes in this pattern can signal earthquakes. Before several major quakes, there were unusual
delays in Old Faithful's eruptions. For example, on the day before a major quake in 1975, the interval lengthened to 120 minutes. The geyser later
resumed its usual pattern.