Ground Deformation: Faulting and Folding

Earthquakes and Mountain- Building

An Earthquake is a rapid vibration of the Earth’s surface

created by a sudden movement of a part of a plate along a fault.

Energy released radiates in all directions from its source, the focus

Energy propagates in the form of seismic waves

L Waves

S Waves

Sensitive instruments around the world record the event

Seismograph

What is a Fault or Fault line?

A Fault is a fracture in rock along which displacement has taken place- associated with a plate

boundary.

Faults can be active or inactive, and can be associated with either

current or old plate boundaries.

Types of Faults

Normal

Reverse

Strike-slip

What causes an Earthquake??

Focus- The location within the Earth where movement

occurs, and an Earthquake originates.

Epicenter- The location on the surface directly above the focus of an earthquake.

Where do Earthquakes occur?

So, how does energy released by slippage at a fault travel through

the ground?

Energy from an Earthquake

travels in seismic waves.

S-Wave Motion – “Side-to-Side” Motion

Surface Waves

Detecting and Locating Earthquakes

Seismograph: A device that records earthquake waves.

Seismogram: The “picture” drawn by a seismograph.

How far is the epicenter of an earthquake from a seismic station, if the difference between the arrival time of the P and the S wave is 5 minutes?

Folding

Folding creates non-volcanic mountains

Folded Mountains

Domed Mountains

Fault-Block Mountains