Monday, December 7Cinder Cones: volcanoes that are steep,

but not very big, usually only erupt once`

Warm-Up: Brainstorm words you think of when you hear, or see, this word

 

A.500 Active volcanoes on the Earth

A. 500-800 Active volcanoes on the Eartha. Over ½ located around Ring of Fire

             i.      50 in the US, third most            ii.      Indonesia and Japan 1 and 2

iii. Other Countries in the Ring of Fire include: New Zealand, Korea, Philippines, Canada, Mexico, Columia, Costa Rica

b. Most volcanoes are located near plate boundaries

c. Some are located at hot spots- weak spots in the earth’s crust where magma has broken through the mantle Ex: Hawaiian Islands

d. Volcanic Islands form when magma repeatedly hardens on top of an underwater volcano and eventually breaks the surface

e. Active volcano – has erupted in recorded history

f. Dormant volcano – not erupted in recorded history

There are three types of volcanoes. Can you name all 3?

1. Shield Cones

2. Cinder Cones

3. Composite

Broad cone resulting from smooth lava that builds up gradually in layers

Don’t erupt explosively

Lava flows from large opening and surrounding cracks in ground

Ash and loose rock (cinders) spewed out explosively from the volcano

Steeper than shield cones

only about 30-400m tall

Usually only erupts once

Commonly occur in groups or fields

Alternating layers of solidifed lava and rock particles

Larger because volcano erupts explosively sometimes and quietly other times

Tend to erupt explosively because of thicker (more viscous) magma/lava

Thicker magma traps gasses; increases pressure

Shape: steep summit, gently sloping lower part

3 Types of Volcanic Debris

1. Lava

2. Tephra (pieces of rock)

3. Ash

Craters can be created when the walls of a volcano collapse after an eruption

Crater Lake in Oregon was formed that way

Caldera – large crater

Can be more than 30 km (~15 miles) in diameter

Yellowstone National Park is in the middle of a caldera!

Yellowstone has hot springs, bubbling mud, and spouting geysers

Why? Because the region is geologically active!!

We can harness the energy that creates these hot springs and geysers and use it to heat our homes and light our classrooms!

This type of energy is called geothermal energy

Tuesday, December 8

• Plutons: large intrusive igneous rock bodies• Warm-Up:

– List and describe the 3 types of volcanoes– Why are geothermal energy plants often located

near areas with volcanic activity?