1. Volcanoes

2. Shield Volcanoes Basaltic magma - from oceanic crust – very dense
Shield shaped- more flat and rounded than other volcanoes – wider than tall
Very quiet non-explosive eruption - Lava erupts from the rift zones or faults on the surface of the cone

3. KILAUEA Exists as a shield volcano
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
KILAUEA
January 3,2003 – 20 year old birthday of eruption that is still going on – Longest eruption known in Earth’s existence

4. Hot Spots
Hot Spots: Not all volcanoes develop along plate boundaries. Sometimes magma works its way up through earth’s lithospheric plates.
Areas where this occurs is called a hot spot.
Hot spots appear to be stationary but are they really? ______ Why? ______________________________________________________________________________________________________.
What is an example of a hot spot? __________________________

6. Volcanic Hot Spot Audio and Visual
click here to view and listen to how hot spots are created

7. Cinder Cone Volcano Characteristics
Granitic lava- only continental crust
“Narrow” bases and the steepest sides
Pyroclastic (aka - tephra) explosions - mixtures of hot, dry rock fragments and hot gases – VERY EXPLOSIVE

8. Paricutin Now stands at a height of 10,400 ft. (3170 meters)
Only one eruption in history—lasted from 1943 to 1952
Inactive since then
Once cinders erupted, the cone was slowly built up and added to over the years in size
A cinder cone volcano
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

9. Composite Volcanoes Made of granitic and basaltic lava
Tall and Wide Mountains - “Middle sized volcano”
Tephra (pyroclastic) and lava flows (at different times)…Can be quiet or very explosive
Examples: Mount Rainier, Mount St. Helens, Mount Shasta, Mount Hood

10. Mount St. Helens Example of a composite volcano
Located in the state of Washington, USA
First estimated eruption occurred about 10,000 years ago
Summit stands at 8,363 feet
57 people died in the 1980 eruption
Also the most examined eruption in recent history
Most recent eruption was in 1990
Oldest rocks on mountain = 40,000-50,000 years old
1980 eruption is one of the most powerful eruptions by Mt. St. Helens in its history