Science Study Guide: Earthquakes and Volcanoes Chapter 1- Unit C
Write the definition to each word.
1. Core- deepest layer of the Earth
2. Seismograph- instrument that records earthquake waves
3. Earthquake- shaking of Earth’s crust
4. Epicenter- point of Earth’s surface right above the focus of an
earthquake
5. Fault- break in Earth’s crust along which rocks move
6. Focus- underground point where an earthquake first starts
7. Crust- layer of the Earth that includes land and the ocean floor
8. Mantle- thickest layer, made of solid and melted rock
9. Plates- continent-sized slabs that make up the crust and upper mantle
Fill in the blank with the correct word or words.
10.Earth’s plates move very slowly across Earth’s surface on a thin layer
of partly melted mantle.
11.Earth’s core is its hottest layer.
12.Scientists can measure earthquakes by using seismographs, the
Mercalli scale, and the Richter scales.
13.Different kinds of eruptions form different kinds of volcanic
mountains.
14.Some volcanoes form new ocean floor as plates move apart and
magma rises to the surface of the crust.
15.California has more than 20,000 earthquakes each year because there
is a large fault running through the state.
Write each short answer in complete sentences.
16.The 1964 earthquake in Alaska released more energy than the 1989
Loma Prieta earthquake in California. How do you think scientists
know this? Explain.
By measuring the two earthquakes, scientists could compare the
amounts of energy the earthquakes released. (using seismographs,
the Mercalli scale, or the Richter scale)
17.The group of volcanoes in the Pacific Ocean basin are known as the
Ring of Fire. Why is this a good name? What do you think causes the
volcanoes in this ring?
Ring of Fire is a good name because of the large number of volcanoes
there. The plates moving toward each other cause the edges of one
plate to be pushed down into the mantle, where it partly melts. Magma
rises through vents all around the edges of the Pacific Plate, forming
the volcanoes.
18.If Earth’s plates stopped moving, what might happen?
There would be no more earthquakes and no new volcanoes or
mountains.
*You will need to label a picture of a volcano: lava, magma chamber,
crater, magma, and vent.