Volcanoes
To: Mrs. Blair
By: Bryant
April 23, 2004
A cinder cone volcano is a very simple volcano. It’s made of the lava with a single vent inside it. When the lava pours out it dries up and makes the volcano bigger. It has a small shaped bowl at the top. The cinder cone is mostly seen in North America.
A cinder cone volcano began on a farm in Mexico in 1943. As the lava built up, it got to be the height of 1,200 feet. It took 9 years to build the cone. In the end the town by the farm was covered by 100 square miles of ashes and destroyed. Many geologists studied the volcano during the time it was growing and they were able to learn a lot about volcanoes.
One thing they learned from this volcano is the order of events. They are eruption, formation of the cone and crater, and then lava flow.
A composite volcano is very steep around its sides. Most of them have a summit on the top with a central vent. The central vent is a vent in the center of a volcano. Two of the many composite volcanoes are Mount Shasta and Mount Fuji. When a composite volcano is dormant, erosion starts to destroy the cone on top of it. The hardened magma inside the cone will be filled up. After that all that remains is a plug.
An
interesting amount of composite volcanoes are in Oregon. They are mostly around
Crater Lake. From the last few eruptions, they have produced a small cinder
cone volcano. The cinder cone is at the waters of Wizard Island. Mount Mazama
has had a big explosion that was almost 6,800 years ago.
Shield volcanoes are very flat. They are built mostly by fluid lava. The fluid lava is called basalt lava. They slowly get higher and higher by the day. Lava usually erupts from vents inside the volcano. Most of them can go to 3 or 4 miles wide. The heights of most of the shield volcanoes go to 1,500 to 2,000 feet high. Hawaii has a lot of shield volcanoes. Two of the worlds most active shield volcanoes are there. Sometimes in eruptions lava pours out quietly. When it does that it usually floods towns.
