Viking halberd Viking halberd The term "halberd" has been used to translate several Old Norse words relating to polearms in the context of Viking Age arms and armour, and in scientific literature about the Viking age. In referring to the Viking Age weapon, the term "halberd" is not to be taken as referring to the classical Swiss halberd of the 15th century, but rather in its literal sense of "axe-on-a-pole", describing a weapon of the more general glaive type. In English translations of sagas, "halberd," "bill," or other terms have been used to translate several different Old Norse words. It is thus
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