What are the factors affects magmas viscosity?
The three factors that influence the viscosity of a lava are temperature, the dissolved gases it contains, and its chemical composition.
What is the main component of Magma?
Magmas can vary widely in composition, but in general they are made up of only eight elements; in order of importance: oxygen, silicon, aluminum, iron, calcium, sodium, magnesium, and potassium (Figure 3.6).
What elements has the highest amount in the magma?
Explanation: Oxygen, the most abundant element in magma, comprises a little less than half the total, followed by silicon at just over one-quarter. The remaining elements make up the other one-quarter. Magmas derived from crustal material are dominated by oxygen, silicon, aluminum, sodium, and potassium.
What are the 3 major types of magma?
There are three basic types of magma: basaltic, andesitic, and rhyolitic, each of which has a different mineral composition. All types of magma have a significant percentage of silicon dioxide. Basaltic magma is high in iron, magnesium, and calcium but low in potassium and sodium.
Which type of magma is most explosive?
andesitic
How do volatiles affect Magma?
Magma invariably contains small amounts of dissolved gas (water, CO2 etc) which is released as pressure is removed. A high volatile content decreases viscosity (like adding water to treacle), and is probably the main factor in enabling some highly viscous (but also volatile-rich) melts to reach the surface at all.
What are the most common volatiles found in Magma?
water
Is high silica magma explosive?
Magmas with high silica content have a high viscosity (resistance to flow) and are generally more explosive when eruptions occur. All magmas also contain some degree of trapped gasses (CO2 & H2O ).
What is the shortest lived type of volcano?
Cinder cones form when thin or runny magma is flung in the air during an eruption, and then hardens and falls back to earth in fragments called “cinders.” Over time, these cinders build up, creating a cone shaped mound. Cinder cones can form rapidly, and are the shortest-lived volcanoes.
What are the 3 major types of volcanoes?
Lesson Summary
- Composite, shield, cinder cones, and supervolcanoes are the main types of volcanoes.
- Composite volcanoes are tall, steep cones that produce explosive eruptions.
- Shield volcanoes form very large, gently sloped mounds from effusive eruptions.
What is the largest type of volcano?
shield volcano
Is a stratovolcano a shield volcano?
Stratovolcanoes have relatively steep sides and are more cone-shaped than shield volcanoes. The lava therefore builds up around the vent forming a volcano with steep sides. Stratovolcanoes are more likely to produce explosive eruptions due to gas building up in the viscous magma.
How many Super volcanoes are on earth?
12 supervolcanoes
What is the difference between a stratovolcano and a shield volcano?
Composite volcanoes, also known as stratovolcanoes, are towering structures, often rising more than 10,000 feet. Shield volcanoes are broad, typically 20 times wider than they are high. These volcanoes can be massive.
Which is more dangerous stratovolcano or shield volcano?
Stratovolcanoes show inter-layering of lava flows and pyroclastic material, which is why they are sometimes called composite volcanoes. Due to the higher viscosity of magmas erupted from these volcanoes, they are usually more explosive than shield volcanoes.
What are some characteristics of a shield volcano?
Shield volcanoes have the following characteristics:
- basic lava, which is non-acidic and very runny.
- gentle sides as the lava flows for long distances before it solidifies.
- no layers, as the volcano just consists of lava.
- less violent eruptions.
- shorter periods between eruptions.
Do Stratovolcanoes erupt violently?
Why do stratovolcanoes erupt violently and shield volcanoes do not? Low-viscosity lavas flow easily, erupt non-violently, and form gently-sloping shield volcanoes. High-viscosity lavas do not flow easily. Pressure builds up within the magma chamber and eruptions are explosive and violent.
Why do shield volcanoes have such a different shape than Stratovolcanoes?
vent and tumble to form slopes of about 30 degrees; they build the cone higher near the vent. Why do shield volcanoes have such a different shape than stratovolcanoes? They erupt where rising basaltic magma encounters near-surface groundwater, An active hotspot volcano lies in the ocean basin near the Hawaiian Islands.
Why are Stratovolcanoes so explosive?
Explosive eruptions occur at stratovolcanoes due to the high gas concentration in the magma. As the magma rises, the gases release, causing the pressure beneath the volcano to increase. Once this pressure becomes large enough, an explosive eruption occurs.
Can a volcano pop up anywhere?
Can a volcano pop up anywhere? Volcanic eruptions don’t occur just anywhere. 60% of all active volcanoes are located at plate boundaries such as the Pacific Plate, which is very well known as the Ring of Fire because of many active volcanoes on its perimeter.