Where do the most violent volcanic eruptions occur?
The most violent eruption recorded in history was that of the La Garita caldera in the United States. It formed 2.1 million years ago and formed a 35 x 75 km crater, which drastically changed the climate of Earth. Fortunately, these eruptions are rare: they occur every 50,000 or 100,000 years.
What happens when a composite volcano erupts?
Composite volcanoes have very sticky and thick lava, which can make them very explosive when they erupt: gas bubbles trapped in the magma chamber have difficulty escaping through the viscous rock. They can also spew masses of hot ash and rock into the air, making them extremely dangerous.
What makes a composite volcano an explosive volcano?
These explosive volcanoes also spew eruptions of small rocks and ash that are deposited on the sides of the volcano. Therefore, we see that composite volcanoes are composed of alternating layers of hardened lava, volcanic ash and rock fragments, which is why they are called 'composite. Are compound volcanoes the most explosive?
What are the dangers of a composite volcano?
When St. Helens erupted, the gentle peak left a bowl-shaped depression – a caldera. Hot lava isn't the only threat compound volcanoes can pose – the ash rising from them can have catastrophic effects. Ash can remain suspended in the atmosphere and significantly affect the world's climate.
What happens to the lava when a volcano erupts?
When a volcano erupts, lava, gases and fragments of rock travel all the way up the main vent and are ejected through the crater. When the eruption ends, the lava may fall back down the tube or form a lava lake in the crater. Lava flow – When magma reaches the surface it is called lava (pronounced 'larvae').
What is the most violent part of an outbreak?
This is the most violent eruption of a volcano. Fine ash, thick lava, and glowing, gas-laden clouds are emitted, moving downhill at high speed. Heavy rain often accompanies eruptions due to the release of steam from the volcano, which will then condense on the atmosphere to form clouds.