Volcanos Flashcards
1
Q
how does a volcano form over time at a separating plate boundary:
A
- As plates separate, a crack forms in the crust of the Earth.
- Magma, from the magma chamber in the mantle, rushes up through this newly formed gap in the crust.
- Lava spills out across the surface of the Earth.
- This lava cools and hardens.
- Many eruptions over time increase the size of the volcano and give it its cone shape.
- Lava from the most recent eruption flows down the outside of the volcano, covering layers of rock that have already cooled and hardened from previous eruptions.
2
Q
How does a volcano form over time at a colliding plate boundary:
A
- When two plates collide, the heavier oceanic plate sinks under the lighter continental plate at a location called the subduction zone.
- A deep ocean trench forms at the subduction zone.
- As the oceanic plate sinks under the continental plate, it melts and is recycled back into the mantle (subduction).
- The heat from plate melting/recycling causes a rise in temperature in this section of the mantle. This increased temperature causes the magma to burn up through the continental plate
- This super-heated magma burns through the crust to form a new volcano. These volcanoes run all the way along the colliding boundary and create a line of volcanoes on the surface of the Earth.
3
Q
Acidic lava
A
Acidic lava is thick, moves slowly and cools quickly. It’s associated with:
• Tall volcanoes with steep sides
• Cone shape
Destructive plate boundaries
• Violent eruptions
4
Q
Basic lava
A
Basic lava is thin, moves quickly and cools slowly. It’s associated with:
• Short and wide volcanoes with gentle sides
• Shield shape
• Constructive plate boundaries
• Non-violent eruptions
5
Q
Active volcano
A
A volcano that erupts regularly and will likely erupt again soon
6
Q
Dormant volcano
A
A volcano that has not erupted in a long time but could erupt again
7
Q
Extinct volcano
A
A volcano that has not erupted in recorded human history
