1. Earth and Space Science
Earthquakes and Volcanoes

2. earthquake
1. An _______________________ is a sudden movement of Earth’s crust.

3. focus, focus
2. The place where the slipping begins is called the earthquake’s
__________________. Waves of energy ripple outward from the _________________.

4. epicenter, epicenter
3. When waves of energy ripple outward from the focus and reach Earth’s surface, the waves spread out from a point directly above the focus called the ____________________. People first feel the ground shaking at the _____________________ of the quake

5. tectonic plates
4. Earthquakes happen along boundaries of _______________
____________ because the pressure from the movement of the
plates pushes nearby faults.

6. primary
Earthquakes produce three different kind of waves: primary waves (P waves), secondary waves (S waves), and surface waves (L waves). 5. ________________ waves move the fastest. They pass through both solid and liquid layers of Earth.

7. secondary, solid
6. ______________ waves move about half as fast as primary waves and only move through Earth’s ____________ layers.

8. surface
7. ______________ waves move the slowest and travel along Earth’s surface. These waves cause the most damage.

9. magnitude, damage
8. _____________________ is the measure of the amount of energy released by an earthquake. The strength of an earthquake can be measured in different ways: _________________________ or the extent of ______________ caused to an area.

10. Richter scale, 1 9. The __________ ________ scale measures magnitude
at the epicenter. It rates earthquakes weakest to strongest starting from _____.

11. Mercalli scale, I to XII, less reliable
10. The __________ ______ scale measures what people felt and what happened to objects. On the Mercalli scale, earthquakes are rated in Roman numerals from ____ to ____(twelve) with XII being the most severe. The Mercalli scale is based on observed effects, not mathematics, so it is __________ __________ than the Richter scale.

12. volcanoes, volcano, tectonic plates
11. ____________________form on land and on the ocean floor. A ____________________ is an openings in the Earth’s crust. Most volcanoes are fond where ______________ _____________ meet.

13. Ring of Fire,
12. The _______________ of _____________ is a circle of volcanoes the surround the Pacific Ocean. The Ring of Fire follows the boundaries of the plates that meet around the Pacific Ocean.

14. eruption
13. Volcanoes are more likely to erupt at plate boundaries than any other place on Earth. An _________________ is an outpouring of melted rock, ash, gases, or a combination of these.

15. vent, lava
14. All volcanoes have at least one _________, or opening. Once magma reaches Earth’s surface, it is called _________________.

16. active, dormant, extinct
15. An _____________ volcano is currently erupting; a _____________ volcano is one that has not erupted in some time; and an _______________ volcano has stopped erupting.

17. thinner
Shield volcanoes are built by _________________, fluid lava that spreads over a large area.

18. thick
Cinder-cone volcanoes are built by ____________ lava that is thrown high into the air and falls down as a cone shape.

19. hardened
Composite volcanoes are built by layers of ash and cinder sandwiched between layers of ________________lava.

20. island chain
16. The Hawaiian Islands are an _______________ ________, or a line of volcanic mountains.

21. hot spot
17. Scientists know that the Hawaaian Islands move with a slowly moving tectonic plate. As it moves, the plate passes over a stationary pool of magma called a __________ __________.

22. volcanic island
18. Over millions of years, lava erupting form the hot spot formed a mountain. Eventually the mountain grew taller than the ocean’s surface and became a _____________ _____________. As the plate moved, that island moved away and a new island began to form.