Lesson 1: Earthquake Risks Review – Dutch reviewed for a test on earthquake risk:
• An earthquake is the rupture and the movement of rocks along a break or crack in Earth’s crust.
• A fault is the surface along which the crust moves. When the forces acting on the rock layers are great enough movement occurs along the fault and energy is released causing the ground to shake. Most earthquakes occur along plate boundaries.
• Earthquakes can change Earth’s surface creating new landforms. Compression and tension forces form ridges and mountains as crust moves vertically. A tsunami is a huge ocean wave caused by an underwater earthquake which makes the ocean floor subside.
• When extreme shaking from an earthquake causes loose sediment to behave more like a liquid than a solid it is called liquefaction. Earthquakes can also trigger landslides which bring rocks and soil from mountaintops into valleys.
Then he took the test on Lesson 1: Earthquake Risks.