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: 

Magmatic eruptions are the most well-observed type of eruption. They involve the decompression of gas within magma that propels it forward. Phreatic eruptions are driven by the superheating of steam due to the close proximity of magma. This type exhibits no magmatic release, instead causing the granulation of existing rock. Phreatomagmatic eruptions are driven by the direct interaction of magma and water, as opposed to phreatic eruptions, where no fresh magma reaches the surface.Within these wide-defining eruptive types are several subtypes. The weakest are Hawaiian and submarine, then Strombolian, followed by Vulcanian and Surtseyan. The stronger eruptive types are Pelean eruptions, followed by Plinian eruptions; the strongest eruptions are called Ultra-Plinian. Subglacial and phreatic eruptions are defined by their eruptive mechanism, and vary in strength.
The lawsuit claimed that Par marketed the product as effective for this use, despite having conducted no well-controlled studies to support a claim of greater efficacy for Megace ES, and prior knowledge of the severe adverse side effects for geriatric patients, including deep vein thrombosis, toxic reactions with impaired renal function, and mortality. Society and culture
Generic names
Megestrol acetate is the generic name of the drug and its INNM, USAN, USP, and BANM, while megestrol is the INN and BAN and mégestrol the DCF of megestrol, the free alcohol form of MGA. The medication is also known by its developmental code names BDH-1298, NSC-71423, and SC-10363. Brand names
MGA is marketed under a variety of brand names throughout the world but is most commonly sold under the brand name Megace. It is also available under the brand name Megace ES in the United States and under the brand name Megace OS in Canada. For use in veterinary medicine, MGA is sold as Ovaban in the United States and as Ovarid in the United Kingdom. Availability
MGA is available widely throughout the world, including in the United States, Canada, the United Kingdom, Ireland, elsewhere throughout Europe, Australia, New Zealand, Latin America, Asia, and a few African countries. It does not appear to be marketed in Germany, Russia, South Africa, Japan, India, or Mexico, among other countries. Generation
Progestins in birth control pills are sometimes grouped by generation.