1. Volcanoes Tungerahua Volcano, Ecuador Picture by Alcinoe Calahorrano
Talk about this volcano when it erupted and what it is doing right now.
Tungerahua Volcano, Ecuador
Picture by Alcinoe Calahorrano
Volcanoes

2. Volcanoes form around vents that release magma onto the Earth’s surface.
Lava
Magma chamber

3. Nonexplosive Eruptions
Volcanic Eruptions
Lava flow
Lava fountain
Nonexplosive Eruptions
Explosive Eruptions
What is Lava?
-magma that flows onto the Earth’s surface

4. The Composition of Magma Determines whether it is explosive or not!
water
High water content
More likely to be !!!
High content
More likely to be !!!
Why?
Silica has a thick, stiff consistency
Flows slowly
Tends to Harden in the volcano’s vent
EXPLOSIVE
silica
EXPLOSIVE
The Earth is made of many different and distinct layers. The deeper layers are composed of heavier materials; they are hotter, denser and under much greater pressure than the outer layers. Core: The Earth has a iron-nickel core that is about 2,100 miles in radius. The inner core may have a temperature up to about 13,000°F (7,200°C = 7,500 K), which is hotter than the surface of the Sun. The inner core (which has a radius of about 750 miles (1,228 km) is solid. The outer core is in a liquid state and is about 1,400 miles (2,260 km) thick.

5. What Erupts from a Volcano?
Blocky lava
Lava can be
thick or thin.
Pahoehoe Aa
Pillow lava

6. What Erupts from a Volcano?
Pyroclastic material
Rock fragments created by eruptions
magma explodes from volcano and solidifies in the air
existing rock is shattered by powerful eruptions
EXPLOSIVE
Lapilli
Volcanic bombs
Volcanic blocks
Volcanic ash

7. How do volcanoes affect the Earth?
Flows and Fallouts
hot ash can flow really quickly
Knock down buildings
Dam rivers (flooding/drought)
Kill crops and livestock
Climatic Changes
Ash & Gases can block sunlight
Drop average global temperature noticeably

8. Types of Volcanoes Shield volcano Cinder cone volcano
Composite volcano

9. Craters, Calderas, and Lava Plateau
From explosions of material out of the vent and the collapse of material back into vent
Caldera
Much larger depression that forms when magma chamber empties and its roof collapses
Lava Plateau
Forms when lava erupts from long cracks, or fissures, and spreads out evenly (thousands of km)

10. What causes volcanoes? The Formation of Magma
Mantle rock melts when the temperature increases
or the pressure decreases.
There are lots of uncertainties about why volcanoes form, because scientists have to rely on models based on rock samples and other data.

11. What causes volcanoes? Where Volcanoes Form
Tectonic Plate Boundaries!!!
There are lots of uncertainties about why volcanoes form, because scientists have to rely on models based on rock samples and other data.
~75% world’s active volcanoes in Ring of Fire

12. What causes volcanoes?

13. What causes volcanoes?
Hot Spots

14. How do volcanologists predict eruptions?
Measuring Small Quakes
Before eruption, increase in number & intensity
Measuring Slope
Bulges may form with magma (tiltmeter)
Measuring Volcanic Gases
Outflow of volcanic gases
Sulfur dioxide, carbon dioxide
Measuring Temperature from Orbit
Measure changes in temperature over time

15. You should not be a Volcanologist if….
You don’t like hiking, backbacking, rockclimbing, etc.
You are not interested in experiencing extreme temperatures and heights.
If you don’t like to travel to incredible places and see breathtaking views of the world.
Robert McGimsey
USGS
A. Ozerov