Question

very big note on volcano​

Answer 1

Answer:

A volcano is an opening in the earth's crust through which lava volcanic ash, and gases escape.

volcanic eruptions are partly

driven by pressure from dissolved gas, much as escaping gases force the cork out of a bottle champagne.

Beneath a volcano liquid magma containing dissolved gases rises through cracks in the earth's crust. As the magma rises , pressure decreases allowing the gases to from bubbles. How the magma behave when it reaches the surface depend on both its content and chemical composition.Lava with low silica contents have low viscosities and flow freely , allowing any gas bubbles to escape readily , while lavas with high silica are more viscous , so that any trapped gases cannot escape gradually.

Answer 2

A volcano is a mountain that has, or has had in the past, lava (hot, liquid rock) erupting from a magma chamber under the surface.

• The movement of tectonic plates causes volcanoes to arise.
• There are 17 main tectonic plates in the Earth's crust. These float on top of the mantle's hotter, softer layer.
• Volcanoes are frequently seen when tectonic plates are separating or joining.
• Volcanoes can also occur in areas where the crust's plates are extending and weakening, such as the East African Rift.
• Volcanoes are rare when two tectonic plates collide.
• Mantle plumes promote volcanic activity away from plate boundaries. "Hotspots," as they're dubbed.