Download ES Ch 2 NOTES Earthquakes

Name_________________________________
Date________
CHAPTER 2 NOTES PACKET
2.1 EARTHQUAKES OCCUR ALONG FAULTS (PG 45-50)
A) Rocks move along faults.
1) Faults are huge breaks in the
__________________________, where movement of
rocks occurs.
a) Some movement is slow and continuous, while
sometimes the rocks on the opposite sides of the
fault lock into place.
2) Stress is the pressure of the rocks
_______________________ on each other.
3) When the _____________________________ gets too
great, the release causes an earthquake, where
the ground moves as the rocks on either side of
the fault jerk past each other.
B) Faults are classified by how rocks move.
1) Normal faults- rocks are being
____________________ apart as one section moves
down.
1
2) Reverse faults- rocks above the fault are being
_____________ together as one section moves up.
3) Strike-slip faults- rocks are pushed
______________________ on either side of the
fault.
2.2 EARTHQUAKES RELEASE ENERGY (PG 51-59)
A) Energy from earthquakes travels through Earth
1) The ___________________ is the underground
location where an earthquake begins.
2) The point directly above the focus on the
_________________ is the epicenter.
3) The crust breaks at the focus and the stored
______________ releases and travels outward in
all directions as seismic waves.
2
a) ________________________________ -travel
the “phastest” so they arrive at seismic
stations “phirst." They travel through
solids and liquids.
b) Secondary wave- arrives at a seismic
station _________. They only travel
through solids.
c) Surface waves- travel along the surface of
the crust and cause most damage. They
arrive last.
B) Seismic waves can be measured.
1) Seismographs are instruments used to
___________________ and record ground movements.
2) When an earthquake occurs the ___________________
of the ground is recorded on paper as a jump.
a) The _________________________ seismograph
records side-to-side motion.
b) The _____________________ seismograph
records up-and-down motion.
3) In order to locate the actual
_____________________ of an earthquake, we need
readings from 3 different seismograph locations.
4) The difference in arrival times of the __________
and S-waves is found and used to calculate the
distance to the epicenter.
3
5) A circle with a radius corresponding to the
distance is drawn around each station and where
the 3 circles meet is the location of the
epicenter.
2.3 EARTHQUAKE DAMAGE CAN BE REDUCED (PG. 60-67)
A) Earthquakes can cause severe damage and loss of
life.
1) Earthquakes vary in size, or
________________________, which is the amount
of energy released.
4
Prince William Sound, Alaska in 1964 is the largest earthquake, measuring at 9.2
2) Movement of the _______________ causes the
ground to shake, damaging roads, dams,
buildings and other structures.
3) Liquefaction occurs when _______________ acts
like a liquid and causes landslides and sinking
structures.
5
4) ____________________________ occur in the same
spot as the original earthquake, where the
rocks are still unsettled along the fault.
5) Tsunamis are caused when ______ is displaced in
the ocean and causes large waves, which come
ashore very quickly.
December 26, 2004 Thailand
Tsunami
B) Scientists work to monitor and predict earthquakes.
1) There are signs to help scientists
_____________________ earthquakes in a
particular area, such as changes in ground
elevation, slow movement of rock sections and
small cracks forming in the ground.
2) A ___________ is when areas along active faults
have few or no earthquake activity for an
extended period of time.
a) Sometimes these gaps are indicators that
___________ may be building for a larger
earthquake in the future.
6
C) Structures can be designed to resist earthquake
damage.
1) Rules have been developed for building
______________ structures.
a) There are
________________________________ between
a building and its foundation absorbs
much of the ground motion.
b) An open space around a building lets the
building shake more gently than the
ground it is built on.
c) Shear walls that contain ___________
supports add strength as do cross braces,
or X-shaped supports.
Earthquake Safety Tips
7
Don't panic — the shaking usually lasts less than a minute, and falling objects and resulting fires
cause most damage. So:




If you're indoors, stay away from glass. Take cover under a table or in a doorway so falling
objects can't hurt you.
If you're outside, move away from buildings and electrical wires. Stand in the open until the
shaking stops.
Don't use candles or any open flames. Earthquakes sometimes break natural gas lines, which
easily catch fire.
If you're in a car, move away from bridges or elevated highways that can collapse. Stop in an
open area and wait until the shaking is over.
8