A change that occurs quickly.

Earthquakes  Earthquakes- Movement or vibration in the rock that make up Earth’s crust.  Earthquakes are caused by the release of stored energy in the Earth’s crust.

Learning From Earthquakes  Scientists “feel” and “listen to” the Earth by using seismographs.  Seismograph- An instrument that detects, measures, and records the energy of earthquake vibration. The 2011 Japan earthquake measured a 9.0 on the Richter Scale.

What Causes Earthquakes?  The plates that make up the Earth’s crust sometimes rub against each other. This spot is called a fault.  Movement begins in the focus. This causes the fault to move and release energy called seismic waves.  Scientists use seismograph readings to learn about the Earth’s interior.

Earthquake Examples Find the focus and the fault The San Andreas Fault in California.

Effects of Earthquakes  Earthquakes can cause landslides or avalanches.  Landslide- Rocks and other material that are shaken loose by an earthquake or heavy rain.  Sometimes heavy rain can cause mudslides.  With all three processes, soil and rock are moved from a high place to a lower place.

Effects of Earthquakes  Tsunamis- Giant waves of water created by underwater earthquakes.  Tsunami waves crash into land and pull rock and soil back into the ocean.

Eruption!!!!  Volcano- When volcanoes erupt, the lava cools to create new land. For example, the Hawaiian Islands.  Magma from below the surface explodes onto the Earth’s surface. With it comes ash, steam, rock, soil, and lava.  The mountain is now different and the lava cools to form new rock or land.

These are the before and after photos of Mount St. Helens. What changes were caused by the volcano’s eruption?

The effects of the 2011 earthquake on Japan. Look what it has done to human- made structures. What would it do to the land?