1. Introduction Video Clip
Volcanoes
Introduction Video Clip

2. Shield Volcanoes Big Island News Clip Type of Magma
basaltic magma - from oceanic crust
very dense
Shape of Volcano
shield shaped; more flat and rounded than other volcanoes
wider than tall
Type of Eruption
Non-explosive
Quiet Eruptions
Lava erupts from the rift zones or faults on the surface of the “shield”
Examples
Mauna Loa (Hawaii) – largest mountain in the world
Galapagos Islands
Iceland
Big Island News Clip

3. KILAUEA 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

4. Cinder Cone Volcano Characteristics
Type of Magma
Granitic lava - only continental crust
Shape
“Narrow” base and the steep sides
Cone-shaped
Type 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:
Paricutin (Mexico)
Cerro Nego (Nicaragua)

5. Paricutin 1944 1946 1948 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
1944
1946
1948

6. Composite Volcanoes AKA: Stratovolcanoes Type of Magma
granitic and/or basaltic lava
Shape
Tall and Wide
Moderately steep
Type of Eruption
Explosive or non-explosive eruptions in different eruptions
Loud or Quiet Eruption
Pyroclastic (Tephra) or Lava Flows
Examples
Mount St. Helens (Cascades)
Mount Hood (Cascades)
Mount Rainier (Cascades)
Krakatoa (Indonesia)
Vesuvius (Italy)
Fujiyama (Japan)

7. Mount St. Helens
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

9. Currently Active Volcanoes

10. 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

11. 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

12. Caldera
a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption.
Video clip