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VOLCANOES By : Adriana, Tiahna, and Carla

A Volcano is …: 

A Volcano is … Volcanoes are opening’s in the earth’s crust. When the volcano erupts gas and rocks come out of the opening. The rock is very hot so it is molten. There are pockets of magma underneath the earth in some parts of the world. The magma presses against rock, the earth’s crust.When the magma finds a spot in the crust where there aren’t very many rocks, it pushes to the surface.

Types of Volcanoes: 

Types of Volcanoes Cinder Cones This is the simplest type of volcano. It is built from particles and blobs of congealed lava ejected from a single vent this volcano has a bowl- shaped crater. Composite Volcanoes They are steep – sided. They have a crater at the summit which contains a central vent or clustered group of vents. Lava either flows through breaks in the wall or issue from fissures on the flanks of the cone. This type of volcano is sometimes called strato volcanoes.

More Types of Volcanoes: 

More Types of Volcanoes Shield volcanoes It is built almost entirely of fluid lava flow. Flow after flow pours out in all directions from a central summit vent or group vents, building a broad gently sloping cone of flat, domical shape, with a profile much like a shield. Lava commonly erupt from rift zones that develop or flanks of the cone . Diameters of 3 or 4 miles. There are heights of 1,500 or 2,000 feet .

Tectonic Plates: 

Tectonic Plates The place where 2 tectonic plates collide is called a convergent boundary. As the descending oceanic plate scrapes the continental plate, it sinks deeper and deeper into the mantle, getting hotter. The combination of increased heat and pressure causes the water in the oceanic crust to be released . The water then mixes with the mantle rock causing it to melt. On its way to the surface, heat from rising magma may cause some of the overlying continental crust to melt and become part of the magma. The silica from the continental crust then becomes part of a gooey, silica rich lava that is likely to cause an explosive eruption when it finally reaches the surface.

Crater Lake: 

Crater Lake Crater Lake is the main feature of Crater Lake National Park. It fills nearly a 4,000 feet deep caldera that was formed by the collapse of the volcano, Mount Mazama. The lake is 5 by 6 miles with an average depth of 1,148 feet. Its deepest point has been measured at 1,949 feet deep. As with any lake, its depth fluctuates with the climate, particularly rainfall. This makes Crater Lake the deepest lake in the U.S. Crater Lake also holds the honor of being the deepest lake in the world. The caldera rim ranges in elevation from 7,000 to 8,000 feet. Crater Lake is known for its famous piece of driftwood named the “Old Man of the Lake.” It is a full sized tree that has been bobbing vertically in the lake for more than a century. It contains one of the most cleanest water in the U.S.

Ring of Fire: 

Ring of Fire The ring of fire is an arc of intense seismic earthquakes and volcanic activity stretching from New Zealand along the eastern edge of Asia. It is composed of over 75% of the world’s active and dormant volcanoes. Three- fourths of earth’s active and dormant volcanoes lie along this arc at the margin of the pacific ocean. The ring stretches from South America, where the Nazca plate dips beneath the South American plate, pushing up the Andes mountains and then north up along the coasts of Central America and Mexico. Volcanoes form where the magma breaks through the plates. In the Pacific Northwest the tiny Juande Fuca plate is sinking beneath the North American plate. As it dips beneath the North American plate and before it melts completely, the two plates can snag and then break free. The result is an earthquake.

Mauna Loa: 

Mauna Loa Mauna Loa is the largest volcano on our planet. It is the most active volcano on earth. Located in Hawaii, it has been erupting for over 100,000 years. The volume of Mauna Loa is 9,600 cubic miles (40,000 cubic kilometers) . It is 4 kilometers above sea level. Mauna Loa means “long mountain.” It is a shield volcano and is made of a rock -type known as tholeiitic basalt.

Types of Eruptions: 

Types of Eruptions There are more than 500 active volcanoes that have erupted at least once with recorded history. Many volcanoes are in and around the Mediterranean Sea. Mount Etna in Sicily is the largest and highest of the mountains. Some volcanoes crown island areas lying near the continents, and others form chains of island in the ocean. The most spectacular eruptions consist of violent explosions that blast great clouds of gas and debris. The type of volcanic eruption is often labeled with the name of a well-known volcano where characteristics behavior is similar.

Types of Lava: 

Types of Lava Blocky Lava Blocky lava is cool, stiff lava that can not travel far from the erupting vent. It usually oozes from a volcano only after an explosive eruption has released much of the gas pressure from the magma chamber. Blocky lava forms jumbled heaps of sharp edged chunks. Pahoehoe Pahoehoe lava flows slowly, forming a glassy surface with rounded wrinkles. The lava gets its name from the Hawaiian word for ‘’ropy’’ because its surface represents coils of rope.

More Types of Lava : 

More Types of Lava Aa Aa is a hawaiian word that refers to a type of lava that has a jagged surface. This slightly stiffer lava pours out quickly and forms a brittle crust. The crust is torn into jagged pieces as the molten lava underneath continues to move. Aa is named after the sound you were to walk across this type of lava bare foot. Pillow Lava Pillow lava forms when lava erupts underwater. It forms rounded lumps that are the size and shape of pillows. Pillow lava has a rounded shape because contact with water causes rapid cooling of the lava’s surface.

Mount St. Helens: 

Mount St. Helens Mt. St. Helens formed a conical, youthful volcano known as the Fuji San at America. During the eruption, the upper 400 meters of the summit was removed by the slope failure. Mt. St. Helens gets its power from the heat deep inside the earth. In the months before the eruption, the surge of molten rock or magma inside it triggered earthquakes. The day it erupted was May 18, 1980. The eruption generated a massive lateral blast that devastated the northern flank of the volcano. It flattened millions of Douglas fir trees over a fan shape of 600 square kilometers.

Mount St. Helens: 

Mount St. Helens This buried, burned, and crushed 51 people. The mountain top lost 1,300 feet of height. The valley of the North Toutle River filled with 3 billion cubic yards of rock, ash, snow, and ice. About 230 square miles were severely damaged. Trees blew down 7 miles away. Mt. St. Helens was known as one of the most pituresque sratovolcanoes in the Cascade range. It caused 1.2 billion dollars in damage. The real name of Mt. St. Helens is Mt. St. Hellacious.

Mt. Pelee Eruption: 

Mt. Pelee Eruption The volcano of Mt. Pelee looms over the village of St. Pierre on the French Carribean Island of Martinque . In January 1902 Mt. Pelee began to show an increase in fumarole activity. The public showed a little concern. On April 23 minor explosions began at the summit. Over the next few days, St.Pierre was showered in ash, and covered with choking gas. An estimated 50 people, mostly children, died by snake bites, along with 200 animals. At about 7:50 a.m., on May 8th , the volcano erupted. A large black cloud of a super-heated gas, ash and rock rolled down the south flank of Mt. Pelee at 100 mph. It struck St. Pierre in less than one minute with hurricane force. Of the 28,000 people in St.Pierre, there were only two known survivors.

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