1. Physical and Ecological Processes
SOL WG.2b

2. Plate Tectonics
The surface of the earth is constantly changing due to plate tectonics and erosion and weathering.

6. Volcanoes
Earthquakes and volcanoes can occur anywhere on the surface of the earth, including underwater, but they are more common at plate boundaries.

7. Volcanoes
Sometimes volcanoes occur far from plate boundaries. These areas are called hot spots. A good example of a hot spot is the formation of the Hawaiian Islands in the middle of the Pacific.

8. Volcanoes
There is an area around the Pacific Ocean where many plates come together known as The Ring of Fire. This area has many active and dormant volcanoes and volcanic eruptions are frequent.

11. Volcanoes Scientists cannot predict when volcanoes will erupt.
People live near volcanoes because volcanic ash is extremely fertile and good for farming.

12. Earthquakes Earthquakes are more common at plate boundaries.
The center of an earthquake on the surface of the earth is called the epicenter.
A seismograph is a device that detects if an earthquake has occurred.
The Richter Scale is a scale used for measuring the intensity of an earthquake.

13. Tsunami
Tsunamis are giant waves caused by earthquakes or volcanic explosions.
Tsunamis can be detected with an early warning system but not all countries have the money to install them.

14. An early warning system in the Pacific Ocean.

17. Tsunami
See a tsunami here:

18. Erosion and Weathering
The surface of the earth is also being formed by erosion and weathering.
Weathering breaks rocks into smaller pieces.
Erosion moves pieces of rock or dirt.

19. Review: Earth Main Ideas
The earth is the only habitable planet in the solar system.
The earth consists of a series of shells that float on one another.
The theory of continental drift explains the formation of the continents

20. Review : Bodies of water
Bodies of Water and Landforms main ideas
Water covers three-fourths of the earth’s surface and makes life possible.
The water on earth is continuously circulated between the atmosphere, the oceans, and the earth.
The ocean floor and the continents have similar landforms.

21. Review: Earth’s Internal Forces
The earth’s crust consists of a number of tectonic plates.
The movement of the tectonic plates continually reshapes the surface of the earth.
Movement of the plates produces earthquakes and volcanoes.

22. Review: Forces Shaping the Earth
Weathering and erosion alter the surface of the earth.
Water, wind, and glaciers cause erosion that produces a variety of landforms.
Weathering and erosion help form soil.