Ossetra genitive case form "осетра" (osetra, 'of sturgeon') of the Russian word "осётр" (osyotr 'sturgeon') from the phrase "икра осетра" (ikra osetra, 'caviar of sturgeon'). At one time, the term "ossetra" simply referred to Russian sturgeon species harvested for this type of caviar. In Russian, there are different names for the species of sturgeon that live in various territories such as "Beluga" ("Huso huso"), Sevruga ("Acipenser stellatus") and Sterlet ("Acipenser ruthenus"). The name Ossetra corresponds to the species "Acipenser gueldenstaedtii", which is much smaller than Beluga sturgeon ("Huso huso"), and has a firmer texture. In the territory of the Russian Federation
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