Earthquake Notes
I. Earthquakes

When plates move very _________ and over a _________
period of time

Eventually a sudden _____________ of the crust occurs at a
particular place: _________________

The majority of earthquakes occur at the ________________
of tectonic _________________.

Individual earthquakes also occur where there is a __________.

A fault is a __________ of__________________ in the ___________ along which some
movement of rock occurs.
A. 3 types of Faults

___________– compression causes
horizontal and vertical movement

Normal: ____________ causes horizontal
and vertical movement

Strike-Slip – _________ causes horizontal
and vertical movement
B. Earthquake Terms

Focus: the area in the crust (________ surface) where
__________ is _____________ during an earthquake
(where the earthquake ________________)

o
______________: 0-70 km
o
Intermediate: ______________ km
o
__________: over 300 km
Epicenter: The __________ on the surface directly
_____________the focus of an earthquake
C. Process (how an earthquake happens!)

As tectonic plates move, __________ causes the
rocks at plate boundaries to ______________
or __________________.

Like a stretched rubber band or a compressed spring, these rocks _________ energy called the
________________________________________.

When the pressure __________ ____ within the crust, the stored energy is suddenly
___________________ as the rocks slip along the fault, and an earthquake occurs.

More than _________ of all earthquakes occur along the _________ of ______________
a. _________________ zones
b. Mid-ocean ______________
c. _____________________ zones (continent-continent convergence)
D. Seismology

The study of _____________________________

Scientists ____________ predict the ____________ date and time of an earthquake

But… they can identify areas __________ to have an earthquake in the next ____ years.
A _______________ measures earthquakes, and seismologists use seismic waves to study

The __________ released by an earthquake _____________
away from the focus in__________________

_____________: relative size of an earthquake
depends on _____________ energy released

Seismographs show the kinds of ________, their
___________________, and the ___________ of the waves

______________ are small tremors that _________ an earthquake

Aftershocks are small tremors that follow _______ an earthquake
E. Scales
•
Magnitude is expressed on the __________________________
–
Study the waves to determine the _______________
and location of the earthquake
–
Uses number ___ & ____
–
Each # indicates_______ times stronger
than the # ___________
•
Ex: A rating of ___ has a magnitude ten
times as great as an earthquake
with a magnitude of ___
–
7 or __________ indicates a major earthquake
( 10-felt all over the ____________)
•
Modified Mercalli Scale: use to rate _____________
–
Roman numerals __ to _____ describes
___________ done by the quake
–
XII : ___________ destruction
–
An earthquake with one magnitude, damage
can __________ depending on the location
F. Seismic Waves

The ____________ of potential to kinetic
energy results in seismic __________

Travel through the ground _____ times faster
than the speed of sound

Seismic waves reach the ____________ at the ___________________
 Body waves – originate from the _______ of the earthquake

P waves (____________ waves) are compression waves
that _____ and ______ rock as they travel
i. Cause particles to move ______ & ________
ii. Move through _______, liquids and __________
iii. 1st waves to ___________ at earthquake

S waves – (shear/ ______________ waves) Body waves
that have reached the surface
i. Cause particles to move ______ to _______
ii. Do _________ travel through liquids
 Surface Waves: ________ & _________ waves

Love waves & Rayleigh waves

Travel along the _____________& more __________

Cause the _________ damage

Love: ____ vertical movement of the surface

Rayleigh: ______ horizontal and vertical movement
G. How to determine the distance to the epicenter
 Need data from ____________ seismographic stations including the spread of S and P waves
and the ___________ between the arrival of the s and p waves.
 Forecasting
o
Based on calculating the _______________
o
2 factors

______________ of area

______________ at which strain builds up
H. Earthquake Hazards
 Factors that determine the severity of damage
o
______________ of buildings

______________ structure = _________ damage
 2) Ground shaking
o
-
tall building – vibrations too _________ (to knock it down)
-short building – vibrations too ___________ (to knock it down)
______________ stories collapsed
 3) Soil Fracture
–
_____________ area = landslides
–
Liquefication = sand becomes _______________ due to ______________
–
___________ materials _____________ the motion
–
Hard/resistant materials _____________ the motion
•
______________, falling over, buildings
•
Underground pipes & tanks ____________ to the surface
Causes
4) Tsunami: A huge__________ generated by an _____________ ______________or landslide
•
•
•
Caused by ______________ motion on the ocean floor
______ ocean
•
Height less than _______
•
_________ 500-800 km/h
Shallow water
•
Height ___________ due to
breakers/shallow water
•
Height may exceed _______