Do Now: What do you know about earthquakes?

Turn and Talk: What kind of damage do you expect from an earthquake? Can it be prevented?

Learning Objective: I will be able to explain what causes earthquakes and where they occur.

Success Criteria: I can explain what an earthquake is. I can explain where earthquakes occur. I can explain what causes earthquakes through elastic rebound and faults.

EARTHQUAKES sudden movement or shaking of the Earth Caused by plate tectonic stresses Located at plate boundaries Resulting in breakage of the Earth’s brittle crust

Earthquake Locations Around the World

Do we understand how and where earthquakes occur?

What do you think causes Earthquakes?

Video Clip: While watching the following clip answer the following: Where do earthquakes occur? What causes an earthquake? What is a fault? What is elastic rebound?

PLATE TECTONIC STRESSES Plate boundaries and faults (= cracks where plate sections are moving in different directions) cause friction as plates move Plates in a fault zone have STICK-SLIP motion Periods of no movement (stick) and fast movement (slip) Energy stored as plates stick, Energy released as plates slip

A. ___________________ Elastic Rebound Theory Sudden release of progressively stored strain Tectonic forces act on a rock over a long period of time Stored energy exceed the rock’s strength Rock suddenly breaks, causing an earthquake

Scarp caused by the Denali fault earthquake Faults The most common source of earthquakes felt by people Fault motions don’t necessarily break the surface. Recent California earthquakes are related to buried thrust faults. Eastern U.S. earthquakes have no surface displacement Faults cause hazards. Scarp caused by the Denali fault earthquake in Alaska, November 3, 2002

EARTHQUAKE DAMAGE Landslides Building damage Liquefaction

EARTHQUAKE DAMAGE Most caused by SURFACE waves (arrive last)

Do we understand what causes earthquakes?

Summary: Exit Slip