Volcano is a mountain that has, or once had, lava (hot, molten rock) erupting from a magma chamber underneath the earth. Volcanoes are created by tectonic plate movement. There are 17 major, rigid tectonic plates in the earth’s crust. These float on the mantle’s cooler, softer layer.
- A volcano is an opening in the crust of the earth by which lava, volcanic ash, and other gases escape. Beneath a volcano, liquid magma is there, which consists of dissolved gases that rise through the earth’s crust.
- Volcanoes erupt when magma( molten rock) rises to the surface of the earth. Magma is formed when the mantle of the earth melts. If the magma is thick, gas bubbles cannot escape, and thus pressure builds up. When the pressure gets too much, it causes the volcano to erupt.
- According to geologists, there are four major types of volcanoes
(I) Cinder cones are volcanoes of the simplest kind. They are comprised of particles and congealed lava blobs expelled from a single vent. It splits into tiny fragments that solidify and collapse like cinders around the vent to form a circular or oval cone as the gas-charged lava is blown violently into the air.
(II) Composite volcanoes are also called stratovolcanoes, these types of volcanoes are cone-shaped, built from many layers of lava, pumice, ash, and tephra. Because they are built of layers of viscous material, rather than fluid lava, composite volcanoes tend to form tall peaks rather than rounded cones.
(III) A shield volcano is a type of volcano usually composed almost entirely of fluid lava flows. It is named for its low profile, resembling a warrior’s shield lying on the ground.
(IV)Lava domes, also known as volcanic domes, are bulbous mounds formed via the slow eruption of viscous lava from a volcano. They are commonly encountered in the craters or on the flanks of large stratovolcanoes. - Hawaii’s Mauna Loa is the largest active volcano on our planet. It is about 4 km(2.5 meters) above sea level.
- The popular Mount Fuji of Japan last erupted in 1707. Earthquakes and tsunami were followed by the eruption. It killed over 30000 people and left the rice fields barren for 100 years.
- When the volcanic lava cools very fast, a shiny black glass is formed, known as obsidian. The edges of this substance are razor sharp.
- There is a supervolcano underneath the Yellowstone national park of the United States. The volcano last erupted around 640,000 years ago. If this supervolcano erupts, the ash would be thrown all over the world. It could change the world climate drastically, which could also be responsible for the extinction of human and other animal species.
- One of the largest volcanic eruptions that is recorded in recent history occurred on the island of Krakatau of Indonesia in the year 1883. The eruption was so huge that most of the island disappeared into the sea.
- When the volcano Krakatau erupted, it made the loudest noise in recorded history – it could be heard hundreds of miles away, and the sound waves traveled around the globe at least three times!
- In some occasions, volcanoes explode with such a force that it blows apart completely. When this happens to an island volcano, it could destroy the full island.
- A new island called Surtur’s Island, near Iceland was born in 1963 because of a volcanic eruption. The volcano erupted under the sea, poured out lava which hardened and formed the island.
- The scorching hot winds from a volcanic eruption can travel at a speed of 300 km\h (185mph) and can burn everything that falls in its way at up to 800 degrees Celsius(1,470 degrees Fahrenheit).
- One theory suggests that 75,000 years ago, the eruption of the supervolcano Toba destroyed so many human lives that only 1,000 couples were left to reproduce!
- Some volcanic eruptions produce finely spun strings of glass that look like candyfloss.
- Toba was the last supervolcano to erupt. The eruption was so violent that parts of India were covered with a layer of ash 6 meters (19 feet) thick, and in Malaysia, the ash was 9 meters (29 feet) thick.
- Some people think the legendary lost city of Atlantis was on a volcanic island that exploded and destroyed the city.
- Jupiter has a moon on which there is a volcano that erupts 30 times that of Mount Everest. The area where gas and other production of eruption fall over an area equivalent to the size of France.
- Enceladus is a moon on planet Saturn; it has ice volcanoes that erupt water.
- 90% of all volcanic activity occurs in the ocean.
- There’s a volcano in Indonesia that spews blue lava.
- Two-thirds of all the people killed by volcanoes lived in Indonesia.
