More Stuff About Earthquakes

Faults

•Any stress on the plates can cause an earthquake if the elastic limit is reached.

•Each type of stress results in a specific type of fault.

Normal Fault

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Reverse Fault

•AKA Thrust Fault

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Strike Slip

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• No change in elevation, rock slides past one another.

Focus and Epicenter

•The focus is the point within Earth where faulting begins.

•The point directly above the focus on the surface is the epicenter.

Types of Earthquakes

• Shallow focus - Foci are less than 70 km depth.

• Intermediate focus - Foci are between 70 and 300 km depth.

• Deep focus - Foci are greater than 300 km.

Which earthquakes are most destructive? Why?

The Benioff Zone is the active seismic zone in a subduction zone.

The main Benioff Zone is 10-20 km below where deformation of the slab produces a focus of earthquakes