Volcanoes

Animation of a volcano

Cinder Cone

Cinder Volcanoes are the simplest type of volcano.

They are built from particles and blobs of congealed lava ejected from a single vent. Lava is blown into the air, which breaks into small

fragments that solidify and fall as cinders around the vent to form a circular or oval cone. Most cinder cones have a bowl-shaped crater at the

summit, and rarely rise more than a thousand feet or so above their surroundings.

Composite/StratovolcanoTypically, composite volcanoes are steep-sided, symmetrical cones of large dimension built of

alternating layers of lava flow, volcanic ash and cinders. Composite volcanoes will rise as much as 8,000 feet above their base. Most composite volcanoes have a crater at the summit, which contains a central vent or a clustered group of vents. One essential feature about composite volcanoes is the conduit system. This is when the magma (molten rock material) from a reservoir deep in the Earth's

crust rises to the surface. This type of volcano is built by the accumulation of materials erupted through the conduit, which increases in size as lava, cinders, and ash are added to its slopes.

Shield VolcanoShield volcanoes are built almost entirely of fluid lava flow. Flow after flow pours out in all directions

from a central summit vent, which builds a broad, gently sloping cone - much like a warrior's shield or a plateau. Shield volcanoes can be easily identified because they are tall and broad, with flat,

rounded shapes.

Olympus MonsLocation: Mars

Type: Shield volcano

Facts:• Olympus Mons a Latin term meaning "Mount Olympus" is the tallest known

volcano and mountain in our solar system

• Roughly the size of the American state of Arizona and three times taller than Mt. Everest; about 20x wider than it is tall.

• The extraordinary size of Olympus Mons is likely due to the fact that Mars does not have tectonic plates. Thus, the crust remained fixed over a hot spot and the volcano continued to discharge lava, bringing it to such a height. Formed the same way as the Hawaiian Islands.

Last Eruption: as recently as 40 mya; may still be an active volcano??

Mt. Pinatubo

Location: Philippines Type: Composite volcano/stratovolcano

Facts:• Has had between 6 and 12 eruption cycles• Largest eruption was 35,000 years ago• Most of the volcano was blasted away in the 1991 eruption• Surrounded by smaller volcanoes that are actually vents to the

larger volcano

Last Eruption: 1991-1992, although it is still an active volcano

Mount Hood

Location: Oregon, USA

Type: Composite volcano/stratovolcano

Facts:• Tallest mountain in Oregon; the base is over 92 miles wide• Has had 4 active eruption periods in the last 15,000 years• Formed 500,000 years ago• Very popular with skiers, hikers and climbers; many communities would be

threatened by a modern day eruption of this volcano

Last Eruption: 1790's, not long before Lewis and Clark's expedition to the Pacific Northwest

KilaueaLocation: Hawaii, USA

Type: Shield volcano

Facts:• Youngest volcano in Hawaii• One of the most active volcanoes

on Earth; over 90% of the surface is covered in lava

• Formed by a hotspot under the Pacific plate

• Most of the volcano is below sea level

• Has a large caldera

Last Eruption: November 2009

ParicutinLocation: Mexico

Type: Cinder Cone volcano

Facts:• Grew in a cornfield in an eruption

that began in 1943; largest period of growth was the first year, continued to grow for 8 years

• Lava flow covered 10 square miles• It’s unique growth cycle allowed

scientists to study volcanoes more closely

Last Eruption:1952

Mount Cotopaxi

Location: Ecuador

Type: Composite volcano/stratovolcano

Facts:• Located in the Ring of Fire• Means “throne of moon”• Has erupted 50 times since 1783• Tallest volcano in Ecuador• It’s eruptions produced mudflows

that traveled over 60 miles

Last Eruption: 1904-has been dormant for the last 35 years

Mount Saint Helens

Location: Washington, USA

Type: Composite/stratovolcano

Facts:• Massive eruption in May, 1980 sent thousands of tons of ash into

atmosphere and covered 150 square miles; the top of the volcano was destroyed in minutes; vegetation has yet to recover

Last Eruption: 2008

Mount Rainer

Location: Washington, USA

Type: Composite/stratovolcano

Facts:• Formed 730,000 years ago• Steepest volcano in Cascade range• Over the last 100,000 years the

erosion has been greater than the growth; due to glaciers

• Has a high number of avalanches; covered in large amounts of ice and snow

Last Eruption: 1894

Mauna LoaLocation: Hawaii, USA

Type: Shield volcano

Facts:• Largest volcano on Earth; one of the

most active• Began to form nearly 1 million years

ago• Makes up ½ the area of the island of

Hawaii• There is a caldera located at the

summit• Has erupted 15 x since 1900

Last Eruption: 1984

Mount Fuji

Location: Japan

Type: Composite/stratovolcano

Facts:• One of the most well-known volcanoes• Japan’s largest volcano/highest

mountain; actually made up of 3 volcanoes

• Currently dormant• Eruptions have resulted in 0 fatalities• Has a large crater from the 1707

eruption• Has erupted 16 times since 781 AD

Last Eruption: 1707

Mount Shasta

Location: California, USA

Type: Composite/Stratovolcano

Facts:• Second highest mountain in the

Cascades

• Erupts approximately every 800 years

• Comprised of 4 overlapping eruption centers

Last Eruption: 1786

Mt. Etna

Location: Italy

Type: Composite volcano/stratovolcano

Facts:• One of the world’s most studied

volcanoes• Second largest active volcano in

Europe• One of the world’s largest

continental volcanoes• Surface is covered by historic lava

flows

Last Eruption: 2008