1. What is a volcano?

2. What is a non-explosive eruption?
The most common type of eruption
Releases a lot of lava that flows calmly
Created most of the sea floor and also the Northwest USA
This is how Hawaii was formed

3. What kind of volcano is this?
A shield volcano – cause its Hawaii
But it could also be a composite – cause they sometimes ooze

4. What is a hot spot?
A very hot place in the mantle of the earth – it burns a hole through the tectonic plates and volcanoes form – this is how Hawaii formed.

5. What kind of volcano is this?
Composite Volcanoes
Describe it
Has both explosive and non explosive eruptions
Sometimes they ooze and leave layers of rock
Sometimes they explode and leave gravel
The most common type of volcano
Sides get steeper towards the top

6. What kind of volcano is this?
Shield Volcano
Describe it
Formed from non explosive eruptions
Gently sloping sides
Large base
Hawaiian islands are shield volcanoes

7. What is lapilli? A pyroclastic material Pebble like bits of magma
Like the ones that made the volcano at Paricutin, Mexico

8. What kind of volcanic eruption is this?

9. What is a volcanic bomb?
A pyroclastic material that is formed when large blobs of magma harden in the air
It basically rains boulders!

10. What kind of boundary is this?
Most earthquakes and volcanoes
occur near subduction zones.
Denser oceanic plates move
under continental plates.
What kind of boundary is this?

11. How does pyroclastic material form?
When magma is ejected from a volcano and hardens during an explosive eruption

12. What is a crater?
A funnel shaped pit around the central vent at the top of many volcanos

13. What is a caldera?
A large semicircular depression that forms when the magma chamber begins to empty and the magma chambers roof collapses

14. What is viscosity? A measure of how fluid something is
high viscosity means slow flow (like pancake syrup)
Low viscosity means fast flow (like water)

15. What is this? Why is it dangerous?
pyroclastic flow
up to 1000 degrees!
Very fast!
Breathing ash will kill you

16. What are volcanic blocks?
A pyroclastic material
Large pieces of solid rock that have erupted from a volcano

17. What is volcanic ash? A pyroclastic material
Tiny, dust-like particles of hardened magma

18. What is this a picture of?
It’s a subduction zone!
Most
earthquakes and
volcanic eruptions occur near subduction zones.
What is this a picture of?
The Ring of Fire

19. What is an explosive eruption?
Incredibly destructive
They create clouds of ash, gas & hot debris.
Magma is thrown in the air and hardens before it drops.
The ash can cause climate change!

20. Which plate is the ring of fire around?
It’s a subduction zone!
Most
earthquakes and
volcanic eruptions occur near subduction zones.
Which plate is the ring of fire around?
The Pacific Plate

21. Which type of lava is this?
Aa – pours quickly, forms a brittle crust, less silica so it has a low viscosity

22. Which type of lava is this?
Pahoehoe – it flows slowly, has a glassy surface, high viscosity (more silica)

23. Which type of lava is this?
Blocky – oozes from volcanoes and does not travel far – more silica so high viscosity

24. Which type of lava is this?
Pillow – forms underwater less silica so it flows quickly low viscosity

25. Label this mountain with: Main Vent, Side Vent, Crater, Ash, and Lava
Ash (pyroclastic material)
Crater
Side Vent
Main Vent
Lava (pyroclastic material)
Label this mountain with: Main Vent, Side Vent, Crater, Ash, and Lava

26. What are the 3 categories of volcanoes?
Extinct – has not exploded in recorded history – probably won’t ever again
Dormant – quiet for 200 years – may erupt again
Active – currently erupting or showing signs that it will soon

27. What do you need to get an explosive eruption?
High silica content – the silica blocks the vents so pressure build up
More water – because water expands rapidly and turns to steam – causes more pressure
More volcanic gases because the gases expand rapidly – like water

28. The pacific plate is shrinking
The pacific plate is shrinking! Subduction is occurring at almost every edge of the plate. That’s why the ring of fire is there!

29. What kind of volcano is this?
Cinder Cone
Describe it
Cinder cones are the smallest volcanoes.
Made of small bits of lava that harden before they hit the ground.
The whole volcano is like a large gravel pile.
Small base with steep sides
Built from pyroclastic material (Paricutin, Mexico)

30. And even if you are not anywhere near the explosion – the ash can be deadly

31. Name 4 signs that a volcano might erupt
1. Change in magnitude of earthquakes
Change in volume and composition of volcanic gases
Change in the slope of the volcano
Change in the temperature of the volcano’s surface