Types Of Volcanos

Volcanoes come in 3 forms:

1-Extinct-these volcanoes hav not erupted in an extremely long time and will never erupt again.
2-Dormant-these volcanoes hav nt erupted in around 2000 years but are not extinct because they are tought to erupt in the future.
3-Active-these volcanoes have erupted recently and are likely erupt again in the future.

There are 2 main types of volcanoes also: Shield Volcanoes and Composite Volcanoes

Shield Volcanoes-these volcanoes are very wide and very gentle sloping sides. For these to form lava/magma is very hot and runny and they often many layers. They are in Hawaii and Iceland.

Composite Volcanoes-these volcanoes have very steep sides compared to the shield volcanoes. These volcanoes are very explosive and often result in spectacular eruptions. The lava/magma in very thick also in these volcanoes.

Yellowstone Caldera

Yellowstone Caldera is the volcanic caldera in Yellowstone National Park. Yellowstone is located in the northwest of Wyoming and it extends to parts of Montana and Idaho. Its is thought to be around 2.1 million years old and last erupted over 64,000 years ago. It measures about 55km by 72km. The BBC have a documentary made about Yellostone titled Supervolcano. This documentary was made in 2000 and the Yellowstone Caldera has often been called Supervolcano ever since.

Yellowstone lies over a hotspot which geologist call The Yellowstone Hotspot. Over the past 17 million years this hotspot has created many large scale volcanic eruptions. The Yellowstone Caldera has also created the last 3 supervolcanic eruptions.

If Yellowstone were to erupt again it would result in millions of lives being taken. However, scientists from the U.S Geological Survey see no evidence of another eruption in the near future but also said that these eruptions are neither regular or predictabe.

Biggets Volcano Eruption Ever!!!

Mount Tambora on Sumbawa Island, Indonesia, is known to be the one of the largest eruptions of all time and also the deadliest of all time in terms of lives taken.

It is believed to have killed 71,000 people. 11,000-12000 of which were killed directly by the eruption. The explosion was heard from Sumatra Island which is over 2,000 km away.

The eruption created global climate problems and 1816 became known as The Year Without A Summer. As a result of the eruption, livestock were killed and crops failed causing the worst famine of the 19th century.

How Volcanoes Work

here is a short video on how volcanoes are formed and also how they work and build up over the many years.

http://video.google.com/videoplay?docid=4469061453115836229&ei=YLsvSen3LKTgiAKthb3dDQ&q=volcanoes+genre%3Aeducational

How Volcanoes Are Formed

The earth is divided into 3 main layers. The core, the mantle and the outer crust. When 2 of the earth's plate boundaries diverse and converse. A new crust is formed on the earth's surface by magma cooling and solidifying. The magma from the mantle then works it's way up to the earth's crust, breaks through and erupts! The layers on the volcano build up over many years. The layers are made of ash, rock and lava that come out of the volcano.

picture from:http://www1.moe.edu.sg/learn@/Quest/winners/primary/yu_neng_pri_volcano_nc/xplopix9.gif

Introduction

hello everyone,

welcome to my blog on volcanos.
this is the spot to get great information and discuss volcanos!!! enjoy