Earthquake, Ch 4 REVIEW
1. Begin your review by re-reading BIG ideas, page 140
2. Walk through the chapter, reviewing each HIGHLIGHTED vocabulary word
3. Now reread the chapter.
FORCES IN EARTH’S CRUST 4.1 page 118
4. Stress adds energy to rock; when it gets too much, it will release via an earthquake
5. There are 3 kinds of stress: tension, compression, and shearing (the arrows show mvmt)
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Faults are breaks in the Earth’s crust: “it’s not my fault the Earth is broken.”
There are 3 kinds of faults: normal, reverse, and strike slip (notice the arrows for each)
Earth can be FOLDED – folded mtsn, STRETCHED- fault block mtns , or UPLIFTED- plateaus
If the Earth’s crust FOLDS, this makes rock bend, you find FOLDED MTNS
If it bends with an ARCH it is an ANTICLINE (hint: A for arch and A for anticline)
If it bends downward like a smile, it is a syncline (hint: s for smile and S for Syncline)
Examples of Folded mtns are: Appalachian mts., Himalayas in Asia, and Alps in Europe
13. FAULT BLOCK MOUNTAINS- when 2 normal faults cut through a block of rock
14. Example: Great Basin Range of mountains between Salt Lake city to LA
15. PLATEAU- when earth’s crust uplifts a large block of rock
EARTHQUAKES & SEISMIC WAVES – 4.2 pp 125
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There are several thousand earthquakes daily, but most are mild.
Earthquakes are the shaking from rock moving under earth’s surface
Earthquakes usually begin in the LITHOSPHERE at the FOCUS
The point on earth’s surface directly above the focus is the ____________________________
There are 3 kinds of seismic waves: ________ ________ & ___________________________
P waves- primary waves- 1st to arrive; compress and expand ground like an accordion; can
damage buildings
S waves- secondary waves; vibrate side to side AND up and down; shake ground violently;
cannot move through liquid
Surface Waves- slower than P and S waves; make SEVERE ground movements; makes the
ground roll like ocean waves
3 scales to measure EQ: ________________ ___________________ ____________________
Mercalli- rates by level of damage AT A GIVEN PLACE- gives a different reading at a different
place; has 12 levels and uses Roman Numerals (I -= 1, V= 5, X = 10)
Richter- measures MAGNITUDE or size of seismic waves, ranges from 1- 10; uses a
SEISMOGRAPH to measure and record; does NOT work well for large or distant EQ
12. Moment Magnitude Scale- estimates TOTAL energy released; good for all sizes and far or near;
also uses data from seismographs
13. Earthquakes 1-3 did not release much energy or cause much damage, and are barely noticed
14. EQ 4-6 cause moderate damage; EQ with 7-+ cause GREAT damage;
15. 8+ magnitude EQ are RARE and the most powerful on Earth
16. During the 20th century (1900s) only 2 earthquakes registered 9+
17. To find the EPICENTER scientists measure the distance between time is takes for P wave and S
wave to arrive. The longer this time is, the farther away the EQ is; then geologists draw at least
3 circles using data from different seismographs around the world. The radius of the
overlapping circles helps find the epicenter
SEISMOGRAPHS 4.3 page 134
1. Seismograph records seismic waves
2. The pen on the seismograph is weighted and the pen draws on paper attached to a spinning
drum; it usually draws a straight line unless it registers vibrations and draws squiggles
3. The heavy weight helps the seismograph resist motion during a quake, the rest of the
instrument is anchored to the ground so it vibrates when seismic waves arrive.
4. The seismogram is the written record
5. Earthquakes cause damage in 4 ways: _______________________, ______________________,
________________________________ & __________________________________________
6. Tsunami-
7. Aftershocks-
8. Liquefaction-
9. Shaking-
Label these drawings below: