Ash erupted into the sky falls back to Earth like powdery snow. If thick enough, blankets of ash can suffocate plants, animals, and humans. When hot volcanic materials mix with water from streams or melted snow and ice, mudflows form. Mudflows have buried entire communities located near erupting volcanoes.
https://www.usgs.gov/faqs/how-do-volcanoes-erupt
Cinder cones. Cinder cones are the simplest type of volcano. They are built from particles and blobs of congealed lava ejected from a single vent. As the gas-charged lava is blown violently into the air, it breaks into small fragments that solidify and fall as cinders around the vent to form a circular or oval cone.
https://pubs.usgs.gov/gip/volc/types.html
While volcanoes can be destructive, they are also responsible for creating rich agricultural soil, minerals like gold and silver, diamonds, hot springs and geothermal energy. So how do these iconic wonders form, and what risks do they really pose? What is a volcano? A volcano is like a chimney that allows hot liquid rock, called magma, to flow from a layer within the Earth and erupt onto the surface.
http://www.abc.net.au/news/science/2017-11-22/volcanoes-heres-what-happens-when-they-erupt/8997014
So hot, in fact, that the rock melts. This molten rock will gradually make its way up to the surface of the earth through a series of cracks. When it reaches the surface of the earth, we refer to it as lava. As layer upon layer of lava builds up, a volcano is formed. There are many factors that determine what kind of lava flow will occur and what type of volcano it will be. The amount of gas trapped in the lava, the kinds of minerals making up the lava, and how much pressure can be trapped in the area all affect the eruption and formation of the volcano. You can read about the types of lava and lava flows.
http://www.familyonbikes.org/educate/lessons/volcanoes.htm
Volcanoes are spectacular — sometimes deadly — forces of nature and Planet Earth is covered in hundreds of them. But how do these iconic wonders form, and what risks do they really pose?
http://www.abc.net.au/news/science/2017-11-22/volcanoes-heres-what-happens-when-they-erupt/8997014
How Do Volcanoes Erupt? Deep within the Earth it is so hot that some rocks slowly melt and become a thick flowing substance called magma. Because it is lighter than the solid rock around it, magma rises and collects in magma chambers.
https://www.usgs.gov/faqs/how-do-volcanoes-erupt
How often do volcanoes erupt? Some small volcanoes only erupt once in their lives, while other volcanoes erupt multiple times. Kilaeua volcano in Hawaii, which has been erupting continuously since 1983, is the world's most active volcano. While some volcanoes erupt at regular intervals, there are always exceptions to the rule.
http://www.abc.net.au/news/science/2017-11-22/volcanoes-heres-what-happens-when-they-erupt/8997014
Volcanoes dominate the landscape in Nicaragua and Costa Rica – big, massive volcanoes rising up out of nowhere. Occasionally, steam or glowing red lava seeps out of tops. How do volcanoes form, anyway? Most volcanoes are formed by the movement of tectonic plates on the surface of the earth. These plates are basically huge pieces of rock that ‘float’ on the mantle (a layer of the earth that is sort-of liquid rock). The tectonic plates are in constant motion, albeit very slow motion.
http://www.familyonbikes.org/educate/lessons/volcanoes.htm
Volcanoes is an interdisciplinary set of materials for grades 4-8. Through the story of the 1980 eruption of Mount St. Helens, students will answer fundamental questions about volcanoes: What is a volcano? Where do volcanoes occur and why? What are the effects of volcanoes on the Earth system? What are the risks and the benefits of living...
https://www.usgs.gov/faqs/how-do-volcanoes-erupt
Some volcanic eruptions are explosive and others are not. How explosive an eruption is depends on how runny or sticky the magma is. If magma is thin and runny, gases can escape easily from it. When this type of magma erupts, it flows out of the volcano. A good example is the eruptions at Hawaii’s volcanoes.
https://www.usgs.gov/faqs/how-do-volcanoes-erupt
how do volcano form
Most volcanoes are formed by the movement of tectonic plates on the surface of the earth.