Geology http://doi.org/khj (2013)

Credit: © THINKSTOCK / ISTOCKPHOTO

Eruptions from geysers begin with an overspill of water, followed by a violent fountain of water and steam. Video footage from inside geysers in Russia shows that this eruption sequence is generated by a highly contorted network of water-filled conduits.

Alexander Belousov at the Institute of Volcanology and Seismology, Petropavlovsk, Russia, and colleagues lowered a video camera into four geysers in Geyser Valley, Kamchatka. The footage shows that the plumbing system in all four geysers consists of a main, vertical upper conduit that is connected by a lower horizontal pipe to a complex system of underground cavities. After an eruption, water flows along the horizontal pipe, filling the vertical conduit until it overflows at the surface. Steam then builds up in the underground cavities and becomes increasingly pressurized until it bursts through the horizontal pipe and up towards the surface, ejecting the water in the main conduit as it escapes.

The observations suggest that periodic geyser eruptions can only occur in rock formations that provide a complex plumbing system of convoluted conduits and cavities, which helps explain why geyser fields are so rare.