Science - Ch. 11 Lesson 2 Flashcards
(25 cards)
What is an earthquake?
An earthquake is a rupture and sudden movement of rocks along with a break or a crack in Earth’s crust.
What is a fault?
The surface along which the crust moves is called a fault
How does an earthquake happen?
When pieces of crust slide past each other, energy is released, causing the ground to shake.
What’s my opinion?
ew, people
Where do earthquakes occur?
Most earthquakes occur near plate boundaries, though some occur very far from plate boundaries.
What do forces do?
Compression and tension forces produce ridges and mountains as Earth’s crust moves vertically.
What is liquefaction?
Liquefaction refers to when extreme shaking causes ground that is made up of loose sediment to behave more like a liquid than a solid.
What can earthquakes cause?
Earthquakes can trigger landslides, which bring rocks and soil from the tops of mountains into valleys.
What is a tsunami and how does it happen?
Earthquakes that happen underwater can cause tsunamis—huge ocean waves created by movement at a fault.
What are volcanoes?
Volcanoes are landforms that form when magma erupts onto Earth’s surface as lava.
Where can volcanoes occur?
• Volcanoes can occur at divergent and convergent plate boundaries and at hot spots.
What are mid ocean ridges?
The mountains that form as lava from a volcano at a divergent boundary builds up and cools
What are hot spots?
Hot spots are locations where volcanoes form far from plate boundaries.
How is volcanic ash made?
At convergent plate boundaries, part of the continental crust can become mixed with magma from the mantle. • When this mixture of molten materials erupts, it does not flow as easily as lava made only of melted mantle. •
How is a volcano formed?
Rising magma and great pressure caused by dissolved gases eventually erupt through cracks in Earth’s surface, creating a volcano.
What are lava flows?
When melted mantle material erupts, it flows over Earth’s surface, creating long streams of molten rock called lava flows.
What is volcanic ash?
Instead of forming lava flows, it often solidifies in the atmosphere, where it breaks into small pieces of lava called volcanic ash
What are explosive eruptions?
Eruptions that eject ash high into the atmosphere are called explosive eruptions. •
How do shield volcanoes form?
Shield volcanoes form after basaltic lava flows have occurred over time.
What do shield volcanoes look like?
Shield volcanoes tend to be large with gentle slopes.
How do composite volcanoes form?
• Composite volcanoes form as lava flows and ash layers deposited by explosive eruptions build up.
What do composite volcanoes look like?
Composite volcanoes often have steep sides and a cone shape
What happens before a volcano erupts?
Before a volcano erupts, magma builds up in the crust in a reservoir called a magma chamber
What is a caldera and how is it formed?
Sometimes the surface above the chamber collapses, creating a large depression in the center of the volcano called a caldera.
