Name ___________________________________ Earth Science
Dynamic Crust-Earthquakes & Earth’s Interior Unit 3
I. LOCAL EVIDENCE OF CRUSTAL MOTIONS:
A. ________________________ & _________________________wears down the Earth’s crust.
_________________________ ____________________________ creates new mountains.
B. Sedimentary beds are deposited as _________________________ _______________ or
C. Evidence of motions within the Earth’s crust is indicated by: label the diagrams
D. _______________________________________ provide direct evidence of crustal movement.
____________________ _________________ and ________________ __________________
are two changes that can be observed after an earthquake.
E. ______________________ ____________________ are used in mapping surveys and indicate
exact positions and elevations. Changes in ______________________ of benchmarks are evidence
that the land is either ____________________________ or ______________________________.
F. Displaced fossils found in mountains have 2 interpretations:
G. _________________________________ is the RISING OF THE CRUST
_________________________________is the SINKING OF THE
A. Two processes that cause earthquakes:
1. The movement of _________________________ inside ___________________________.
2. _______________________ is the movement of rock along a surface where the rocks are broken.
B. ___________________ movement of the crust over long periods of time builds _______________
within the rocks. Increased pressure causes the ___________________ ______________________
to break creating a _________________________. When faulting occurs energy radiates through the
Earth as __________________ ________________ that cause the ground to ________________.
III. MEASURING THE EARTHQUAKES:
A. There are 2 scales to measure earthquakes
B. _________________________________ scale is based upon the observations of people and the
damage caused. It measures the ____________________ of the earthquake from ______ to ______
C. _________________________ uses the seismograph to determine the _____________________
Magnitude is the total _______________________ released by the earthquake.
It’s numerical scale is _________ to _________. Each numeric step represents a _______ increase.
IV. PARTS OF THE EARTHQUAKE:
A. The place underground where the break or fault occurs is the
_____________ of the quake
The _________________________ is the location along the
surface of the earth just above the focus where the quake is felt most strongly
A. The two most important energy waves are:
B. Characteristics of P-waves (primary)
C. Characteristics of S-waves (secondary)
D. Both S and P waves travel FASTER through ____________________ material.
V. FINDING THE EPICENTER:
A. The seismograph records the _____________________________ and
(Use the chart on page 11 of your reference table)
Use you Find the
Reference best fit
Table on the curve
page 11 Mark off the difference in and read the
arrival time distance
of S and P waves on a below
B. The steps for calculating your distance from the epicenter:
1. The arrival of the P-wave is 12:03:00 The arrival of an S-wave is 12:07:00
The difference is _____________________
How far is this earthquake from this seismic station? ____________________
2. The arrival time of the P-wave is 2:05:00 The arrival time of the S-wave is 2:08:00
The difference is: _____________________
How far is this earthquake from the seismic station? _______________________
3. If the difference in arrival time between P and S waves is 2min. 35 sec. What is the distance
from the earthquake to the seismograph station? _________________________
4. How long does it take for a P-wave to travel from the focus of an earthquake to a seismograph
station 2,000 km. away? _______________________________
How long will the S-wave take to travel to this same station? ______________________
5. What is the difference in arrival time between P and S waves for an earthquake that is
5,000 kilometers away from the seismograph station? ______________________________
VII. THE ORIGIN TIME OF AN EARTHQUAKE:
A. An earthquake wave detected at __________________________ times by observers at
____________________ distances from the epicenter.
B. To find the origin time seismologists need to know:
A seismograph recording station located 5,700 kilometers from an epicenter.
It receives a P-wave at 2:45 P.M.
At what time did the earthquake actually occur at the epicenter?
VIII. THE LAYERS OF THE EARTH:
A. The crusts thickness ______________________.
It is __________________ under the oceans
and ____________________ under the continents.
Continental crust is mostly ____________, __________ density & _________________________
The ocean basins are mostly ______________ and ________________ or __________________
B. Inferred characteristics of the Earth’s Interior:
1. Studying the ____________________________ of
allows us to make inferences about the structure
and composition of the Earth’s interior.
2. The _______________________ of a seismic wave changes with the ________________ of
the material it travels through. Waves are also ___________________________________
as they travel through materials with different densities.
We know that P-waves can be transmitted through ___________ __________ & ___________
S-Waves can be transmitted through ONLY ________________
3. Earth Quake Shadow Zones:
When an earthquake occurs both ____________ are received from most of the earth.
Opposite sides of the earth where the epicenter is, receives ____ but NO _______ because
S-waves cannot penetrate the ________________ outer core.
______________________ (bending) occurs at the __________________ ( boundaries)
Draw a diagram of the earth’s interior and label and describe each layer or part:
A- Inner Core:
B- Outer Core: