Square dance square dance, very rarely are two modern Western dances ever alike. Like traditional square dancing, recovering from occasional mistakes is often part of the fun. Dancers are encouraged to dance only those programs at which they are reasonably proficient, the default level of achievement being the Mainstream program. All programs are set by Callerlab, the callers' international association, which also governs the training of callers. Irish and Scottish dances are normally done to traditional tunes. English dances may be done to traditional tunes, though, especially at ceilidhs, there is experimentation with many different musical styles. The two types of American
Types of volcanic eruptions Types of volcanic eruptions Several types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior has been observed. Some volcanoes may exhibit only one characteristic type of eruption during a period of activity, while others may display an entire sequence of types all in one eruptive series. There are three different types of eruptions. The most well-observed are magmatic eruptions, which involve the decompression of gas within magma that