Ch. 2 Sec. 2 Review Questions
1. Why does the greatest shaking of the ground
occur near an earthquake's epicenter?
Seismic waves lose more energy the further they
travel.
2. What information do you need to completely
describe where an earthquake started?
It's epicenter and depth (focus)
3. What types of information can a scientist get
by studying seismographs?
Where earthquakes start and how strong they
are.
Ch. 2 Sec. 2 Review Questions
4. How are the primary and secondary waves
similar? How are they different?
PRIMARY
SECONDARY
-Second waves
-Fastest seismic
to arrive at a
-both travel out location after an
waves
from the focus of earthquake.
-First to reach an earthquake
any location
-Travel @ about
-both can travel
after an
half the speed of
through Earth's
earthquake
primary waves.
interior
-Primary means
-They can NOT
"first"
travel through
liquids or solids.
Ch. 2 Sec. 2 Review Questions
5. What information could you get about an
earthquake's location from only two seismic
stations' data? Explain.
Circles showing distances from two stations to
the epicenter will usually intersect in two places,
only one of which can be the actual epicenter.
6. Why might an earthquake's primary waves,
but not its secondary waves, reach a location on
the other side of the world from the epicenter?
Secondary waves can not pass through Earth's
outer core, but primary waves can.
Hmm...who REALLY completed the
reading??
1. How do scientists often name their earthquakes?
Usually after the city that is closest to its epicenter.
2. In what year did an earthquake stop baseball's World Series
at Candlestick Park in San Francisco?
1989
3. How many types of seismic waves exist?
Three--primary, secondary, and surface.
4. What is the average speed of a primary wave?
5 kilometers per second (3 miles per second)
5. What type of waves leave at the same time as primary
waves?
Secondary
6. How did scientists learn that the Earth's outer core was a
liquid? B/c the secondary waves could not pass through Earth's
outer core.
Hmm...who REALLY completed the
reading??
7. Which type of waves cause the largest ground
movements and most damage?
Surface waves
8. What do we call the place where ground movements
are measured?
Seismic Stations
9. What is the recording called that a seismograph
produces?
Seismograms
10. What is the FIRST step in locating the epicenter of
an earthquake?
1. Find the difference in the arrival times of the primary
and secondary waves @ each of the three locations.
earthquakes
vibrations
seismic waves
first movement
along fault
underground
X
the house on the right will shake first b/c it is closer to the focus.
primary waves are the fastest seismic waves.
they can travel through solids, liquids, gases.
Secondary waves travel through the interior @ about 1/2
the speed and can not travel through liquids or gases.
Surface waves cause the most damage and travel the
slowest. They occur along Earth's surface.
Earthquake
instrument
Ground movements
lines
The seismograph contains suspended weight. When the ground
moves, the weights stay in place. Pens attached to weights record
movement.
3 seismograms are needed to locate Seismograms are used to locate a
focus
an epicenter
They record how much the ground
moved.