Magma chamber of magma chambers can be mapped using seismology: seismic waves from earthquakes move more slowly through liquid rock than solid, allowing measurements to pinpoint the regions of slow movement which identify magma chambers. As a volcano erupts, surrounding rock will collapse into the emptying chamber. If the chamber's size is reduced considerably, the resulting depression at the surface can form a caldera. Magma chamber A magma chamber is a large pool of liquid rock beneath the surface of the Earth. The molten rock, or magma, in such a chamber is under great pressure, and, given enough time, that pressure can
Journey to the Centre of the Earth (album) flee the forest for the Lidenbrook Sea and enter a dark tunnel that plunged deep into rock which they blast through with dynamite. The explosion causes an earthquake, and they become trapped in an active volcano shaft which projects them to the surface of the Earth by Mount Etna in Sicily. The concerts and album were first announced in October 1973, and organised during a break when Yes were touring "Tales from Topographic Oceans". Two sell-out performances were held at 6 and 8 p.m. on Friday 18 January 1974 at the Royal Festival Hall in London, attended by 3,000 people