Polka in the United States Blazoncyzk's "Polka Fireworks" festival in Pittsburgh, are run by polka stars or polka fans. These festivals usually last several days and involve performances, dancing, jam sessions, beer, ethnic food, athletic events, parades, and polka masses. Though many festival attendees belong to an older generation, there are also a substantial number of young participants. Polka music and polka festivals are often described as "happy" and "joyful" by their organizers and participants. In their book Polka Happiness, Charles and Angeliki Keil describe the aspects of these "polka parties" that allow them to bring joy to people of all ages. A wide variety
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