What are the 3 factors that determine the strength of a volcanic eruption?
The style of eruption depends on a number of factors, including the magma chemistry and content, temperature, viscosity (how runny the magma is), volume and how much water and gas is in it, the presence of groundwater, and the plumbing of the volcano.
What makes a volcanic eruption more explosive?
When magma is rapidly expelled from a volcano, it undergoes rapid cooling. This induces the formation of crystals, resulting in a sudden increase in the viscosity of the magma. In turn, this produces magma fragmentation, creating a highly explosive eruption.
Where does the strength of a volcanic eruption come from?
Although there are several factors triggering a volcanic eruption, three predominate: the buoyancy of the magma, the pressure from the exsolved gases in the magma and the injection of a new batch of magma into an already filled magma chamber.
What does a volcanic eruption depend on?
Some volcanic eruptions are explosive and others are not. The explosivity of an eruption depends on the composition of the magma. If magma is thin and runny, gases can escape easily from it. When this type of magma erupts, it flows out of the volcano.
What determines the type of volcano that forms?
When magma erupts at the surface as lava, it can form different types of volcano depending on:
- the viscosity, or stickiness, of the magma.
- the amount of gas in the magma.
- the composition of the magma.
- the way in which the magma reached the surface.
How can you predict when a volcano will erupt?
How can we tell when a volcano will erupt?
- An increase in the frequency and intensity of felt earthquakes.
- Noticeable steaming or fumarolic activity and new or enlarged areas of hot ground.
- Subtle swelling of the ground surface.
- Small changes in heat flow.
- Changes in the composition or relative abundances of fumarolic gases.
What two factors control the explosiveness of an eruption?
Volcanoes
| Question | Answer |
|---|---|
| These two factors control whether an eruption will be explosive or quiet? | Water vapor and silica |
| Magma that is low in silica and produces nonexplosive eruptions is called? | basaltic |
| Magma that is high in silica and produces explosive eruptions is called? | granitic |
Which of the following materials from volcano determines its explosiveness?
Explosive eruptions are favored by high gas content & high viscosity magmas (andesitic to rhyolitic magmas). The explosive bursting of bubbles fragments the magma into clots of liquid that cool as they fall through the air.
Why volcanic eruptions vary in their magnitude?
Volcanic eruptions vary in their duration, amount of material released and their type (effusive/explosive). Therefore, it is difficult to compare one eruption with another. magnitude – the amount of material erupted from the volcano. intensity – the speed material erupts from the volcano.
How does volcanic eruption affect the biotic factors?
Livestock and other mammals have been killed by lava flows, pyroclastic flows, tephra falls, atmospheric effects, gases, and tsunami. They can also die from famine, forest fires, and earthquakes caused by or related to eruptions. Eruptions can influence bird migration, roosting, flying ability, and feeding activity.
What determines whether a volcanic activity will be lava flow or a pyroclastic eruption?
Volcanic eruptions can be explosive, sending ash, gas and lava high up into the atmosphere, or the magma can form lava flows, known as effusive eruptions. Whether an eruption is explosive or effusive largely depends upon the amount of gas in the magma.
Does the height of a volcano determines its explosive power?
All volcanoes have a magma chamber, where magma is stored and builds up. They also have a central vent, which the magma travels through to get to the surface. At the top of the volcano is a crater. The height of a volcano determines its explosive power.
How is the nature of a volcanic eruption determined?
The nature of a volcanic eruption is determined by the temperature, viscosity and the amount of dissolved gases in the magma, according to San Diego State University.
Can a large earthquake cause a volcano to erupt?
Sometimes, yes. A few large regional earthquakes (greater than magnitude 6) are considered to be related to a subsequent eruption or to some type of unrest at a nearby volcano. However, volcanoes can only be triggered into eruption by nearby tectonic earthquakes if they are already poised to erupt .
How does viscosity affect the composition of magma?
Viscosity, or resistance to flow, is one of the most important aspects of magma composition, as the University of Rhode Island states. Magmas with low viscosity, such as basaltic magmas, are more like fluids and allow gases to escape with relative ease.
