1. Ch. 13 Volcanoes
Volcano: A vent or fissure in Earth’s surface through which magma and gases are expelled.
Often volcanoes look like mountains.
There are three major types of volcanoes.

2. Most chains of volcanoes exist where oceanic crust subducts beneath continental crust Happens at a convergent boundary

4. Magma: Liquid rock produced under the Earth’s surface that is formed
Magma: Liquid rock produced under the Earth’s surface that is formed when crust melts.
Can melt in three ways
High temperature
Pressure causes the melting point to be lower
Water makes the melting point lower
Volcanism: Activity that includes the movement of magma toward or onto the Earth’s surface.

5. Hot Spot: A volcanically active area on Earth’s surface, commonly far
Hot Spot: A volcanically active area on Earth’s surface, commonly far from a tectonic plate boundary.

6. Caldera: A large, circular depression that forms when the magma chamber below a volcano partially empties and causes the ground above to sink.

7. Ch. 12 Earthquakes
Earthquakes: Movements of the ground caused by a sudden release of energy when rocks along a fault move.
San Andreas Fault, California
Marina District, San Francisco, CA

8. Earthquakes are caused by sudden movements of tectonic plates.
-Usually at transform boundaries
- Frequent earthquakes in a given zone are evidence that two or more plates may meet in that area.

9. Parts of an Earthquake
Focus: The location along a fault in the Earth where the first motion of an earthquake occurs.
Epicenter: The point on Earth’s surface that is directly above an earthquake’s starting point.
Surface wave: A seismic wave that travels along a medium and has a stronger effect near the surface than on the interior
Body waves are waves that travel through the medium (Under the surface)
P and S waves are two different types of waves

10. Studying Earthquakes
Seismograph: An instrument that records vibrations in the ground.
Magnitude: A measure of the strength of an earthquake.
The higher the number the stronger the earthquake is. The strongest earthquake recorded was a 9.5!
Intensity: The amount of damage caused by an earthquake.

11. Tsunami: A giant ocean wave that forms after a volcanic eruption, undersea earthquake, or landslide.
Major tsunami in 2004 in Japan. Another in 2011.
Debris is coming across that Pacific and reaching the West Coast.

12. Tsunami Most often caused by an underwater earthquake
Transform boundary
Results in major destruction and flooding