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

2. Volcano Stats Definition of Volcano Number of active volcanos = ?
Mountain that forms when molten rock (magma) is forced to the Earth’s surface
Number of active volcanos = ?
20 erupting right now (50-60/year) (160/decade)
Number of volcanologists = 1,500
MASS, DENSITY, AND ESCAPE VELOCITY The Earth's mass is about 5.98 x 1024 kg. The Earth has an average density of 5520 kg/m3 (water has a density of 1027 kg/m3). Earth is the densest planet in our Solar System. To escape the Earth's gravitational pull, an object must reach a velocity of 24,840 miles per hour (11,180 m/sec).

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. Volcano Model
Demonstration

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

6. 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.

7. Explosive Volcano Model
Demonstration

8. Questions a. What physical event causes explosive eruptions?
b. Would high water content increase the likelihood of having an explosive eruption?
c. Would high silica content increase the likelihood of having an explosive eruption?

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

10. 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

11. 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

12. Types of Volcanoes
Shield volcano- a low profile volcano usually built almost
entirely of fluid lava flows. (Resembles a warriors shield laying on the ground)
Cinder cone volcano- a steep cone
shaped volcano with layers of cinder and
pyroclastic ash
Composite volcano-  is a conical volcano built up
by many layers of hardened lava, tephra, pumice, and volcanic ash

13. 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)

14. 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.

15. 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

16. What causes volcanoes?

17. What causes volcanoes?
Hot Spots- are places within the mantle where rocks melt to generate magma.
(Basically, a hole in the lithosphere that allows magma to reach the surface as a volcano) 

18. 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

19. 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

20. Parts of a Volcano