Halberd forms of the voulge in design and usage. The halberd was usually 1.5 to 1.8 metres (5 to 6 feet) long. The word has also been used to describe a weapon of the Early Bronze Age in Western Europe. This consisted of a blade mounted on a pole at a right angle. A very similar weapon, the dagger-axe, from Bronze Age China, has also been called "halberd" in English. The halberd was inexpensive to produce and very versatile in battle. As the halberd was eventually refined, its point was more fully developed to allow it to better deal with spears
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