What causes Earthquakes?

Earthquakes What is happening when an Earthquake occurs?

Earthquakes What is happening when an Earthquake occurs? The Earth’s crust moves suddenly.

Earthquakes What is happening when an Earthquake occurs? The Earth’s crust moves suddenly. Built up tension between two plates is released very quickly and the plates move.

Earthquake key terms: Foot wall: The plate that doesn’t move during an Earthquake.

Earthquake key terms: Foot wall: The plate that doesn’t move during an Earthquake. Hanging wall: The plate that moves during an Earthquake.

Earthquake key terms: Foot wall: The plate that doesn’t move during an Earthquake. Hanging wall: The plate that moves during an Earthquake. Fault plane:The plane along which the break between two plates occurs.

Earthquake key terms: Foot wall: The plate that doesn’t move during an Earthquake. Hanging wall: The plate that moves during an Earthquake. Fault plane:The plane along which the break between two plates occurs. Fault line: The line in the surface of the Earth caused by the fault plane.

Earthquake key terms: Focus: Exact point where the earthquake begins.

Earthquake key terms: Focus: Exact point where the earthquake begins. Epicenter: place on the surface of the Earth directly above the focus.

Earthquake key terms: Focus: Exact point where the earthquake begins. Epicenter: place on the surface of the Earth directly above the focus. P-Waves: 1st set of waves which travel quickly through the interior of the Earth in a spiral motion.

Earthquake key terms: S-Waves: Secondary waves – move slowly through the Earth in an “S” shaped motion.

Earthquake key terms: S-Waves: Secondary waves – move slowly through the Earth in an “S” shaped motion. Surface Waves: move in a circular pattern on the surface of the Earth. Causes damage to the surface of the Earth.

Earthquake types: The type of Earthquake depends on what type of boundary is between the two plates.

Earthquake types: The type of Earthquake depends on what type of boundary is between the two plates. Strike-slip Earthquakes: Result from transform boundaries

Earthquake types: The type of Earthquake depends on what type of boundary is between the two plates. Strike-slip Earthquakes: Result from transform boundaries Normal Earthquakes: Result from divergent boundaries

Earthquake types: The type of Earthquake depends on what type of boundary is between the two plates. Strike-slip Earthquakes: Result from transform boundaries Normal Earthquakes: Result from divergent boundaries Reverse Earthquakes: Result from convergent boundaries.

Strike-slip Earthquakes

Strike-slip Earthquakes

Normal Earthquake:

Reverse (Thrust) Earthquake:

Graben:

Horst:

Where do Earthquakes happen?

Where do Earthquakes happen? Most of the time they happen where plates meet.

Where do Earthquakes happen? Most of the time they happen where plates meet. They can happen in the middle of a plate as well.

Where do Earthquakes happen? Most of the time they happen where plates meet. They can happen in the middle of a plate as well. This is usually caused by the crust dropping like a sink hole.

Measuring Earthquakes: The Richter Scale: Measures the amount of energy released by an earthquake (magnitude).

Measuring Earthquakes: Mercalli scale: Measures the intensity of an earthquake (how much damage is done).