Introduction Video Clip

• Type of MagmaType of Magma – basaltic magma - from oceanic

crust – very dense

• Shape of VolcanoShape of Volcano – shield shaped; more flat and

rounded than other volcanoes – wider than tall

• Type of EruptionType of Eruption – Non-explosive – Quiet Eruptions– Lava erupts from the rift zones

or faults on the surface of the “shield”

• ExamplesExamples – Mauna Loa (Hawaii) – largest

mountain in the world– Galapagos Islands– Iceland

•Big Island News Clip

•One of the most active volcanoes on Earth

• Towers at a height of 4,190 feet above sea level

• 1,000 year old lava envelopes the exterior of this volcano

January 3, 2013– 30 year old birthday of eruption that is still going on – Longest eruption known in Earth’s existence

Cinder Cone Volcano Characteristics

• Type of MagmaType of Magma– Granitic lava - only

continental crust• ShapeShape

– “Narrow” base and the steep sides

– Cone-shaped• Type of EruptionType of Eruption

– Very Explosive – due to high content of gases in magma

– Loud Eruptions– Pyroclastic (aka - tephra)

explosions – mixtures of hot, dry rock

fragments and hot gases• Examples:Examples:

– Paricutin (Mexico)– Cerro Nego (Nicaragua)

•Located in Mexico

• February 20, 1943—Farmer noticed bulge growing in cornfield-within week grew to 100 meters in height

• Within five months of the first eruption, the town was evacuated and lay covered in ash and lava

•Only one eruption in history—lasted from 1943 to 1952 1948

1946

1944

• AKA: StratovolcanoesAKA: Stratovolcanoes• Type of MagmaType of Magma

– granitic and/or basaltic lava• Shape Shape

– Tall and Wide– Moderately steep

• Type of EruptionType of Eruption– Explosive or non-explosive

eruptions in different eruptions– Loud or Quiet Eruption– Pyroclastic (Tephra) or Lava Flows

• ExamplesExamples– Mount St. Helens (Cascades)– Mount Hood (Cascades)– Mount Rainier (Cascades)– Krakatoa (Indonesia)– Vesuvius (Italy)– Fujiyama (Japan)

•

•Located in the state of Washington, USA in the Cascades Range

•First estimated eruption occurred about 10,000 years ago

•57 people died in the 1980 eruption, one of the most powerful eruptions in its history

•Video Clip

Currently Active Volcanoes

• http://www.volcanodiscovery.com/erupting_volcanoes.html

Volcanic Eruption Detection

• Geologists can predict volcanic eruptions to a certain degree by monitoring the following:– Earthquakes– Gas emission changes– Mountain deformation via GPS and satellites

Crater

• a circular depression in the ground caused by volcanic activity. It is typically a basin, circular in form within which occurs a vent (or vents) from which magma erupts as gases, lava, and ejecta

Caldera

• a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption.

• Video clip