Download Ring of Fire and Quakes

Ring of Fire and Quakes
Original Source: Dr. Leslie Sautter (Dept. of Geology, College of Charleston)
Grade Level:
SC Standards:
National Standards:
8th
8th – IIIB3c,d,g,j
Earth and Space Science Content Standard D
.
Focus Question
Teacher Preparation
What are the relationships among the locations
of earthquakes, active volcanoes and plate
boundaries?
If this activity will be presented using an LCD
projector, the powerpoint presentation “Ring of Fire
and Quakes” should be downloaded.
Objectives
If this activity will be presented using an overhead
projector, the following preparations are necessary:
1. Photocopy Figures 1-5 onto overhead
transparencies.
Students will:
compare distributions of shallow and deep
focus earthquakes.
compare distributions of volcanoes with
earthquakes.
compare earthquake and volcano
distributions with plate boundary locations.
make inferences of what is occurring at
different plate boundary locations.
2. If the overheads are in black and white:
a.
Figure 3: With a yellow transparency
marker, color over the areas where there
are dots that represent deep focus
earthquakes.
b. Figure 4: With a red transparency marker,
fill in the circles that represent sites of
recently active volcanoes.
Key Words
earthquake focus
epicenter
Pacific Ring of Fire
Time Frame
divergence
One 50-minute class period
convergence
Suggested Learning Environment
Materials
This activity is written for the teacher to
conduct with the entire class, using either an
LCD or overhead projection.
“Ring of Fire and Quakes” powerpoint
presentation, (by L. Sautter)
computer
LCD projector
Relevant pages in Of Sand and Sea
or
Chapter I, The Ocean Planet, pp. 7-16.
overhead transparency copies of Figures 1-5
overhead projector
physiographic map of the continents
red and yellow overhead transparency
markers (not necessary if overheads are
printed in color)
tape
COASTeam Program, Project Oceanica, College of Charleston
1
Ring of Fire and Quakes
TEACHER PAGES
Teacher Background Information
Procedure
The teacher should review basic information about
earthquakes:
An earthquake is the sudden release of a
tremendous amount of energy from within the
earth‟s interior. This release of energy is often
from a location where tremendous friction has
prevented rocks under stress from fracturing
or moving. When the stresses exceed the force
of friction, the built-up energy is suddenly
released.
Earthquake energy travels through the earth in
the form of seismic waves.
The point of origin of an earthquake (i.e., where
the energy is released) is called the earthquake
focus. The plural of “focus” is “foci.”
Earthquake foci occur at depths ranging from
the earth‟s surface to approximately 700 km
below the surface. Scientists group the foci
into three broad groupings, based on the depth
of the earthquake. These groups and their
approximate depth ranges are:
o shallow focus (0-50 km),
o intermediate focus (50-300 km)
o deep focus (300-700 km)
The point plotted on a map directly above the
earthquake focus is called the earthquake‟s
epicenter. Therefore, on a map, different
symbols will indicate the epicenter locations of
shallow, intermediate, and deep focus
earthquakes.
The following instructions are intended for the
teacher to use as a classroom demonstration, using
the powerpoint “Ring of Fire and Quakes,” or using
overhead transparencies. Text in blue italics and in
parentheses relate to instructions if the teacher is
using overhead transparencies.
The lettered items (a, b, c, etc.) are the
instructions or questions the teacher might pose to
the class.
1.
Slide 1 - “Physiography of the seafloor.”
(Show overhead Figure 1.)
a.
Review the large-scale seafloor features of
the Pacific and Atlantic Ocean basins.
2. Slide 2 - “Distribution of shallow focus
earthquake epicenters.”
(Remove Figure 1 and show Figure 2 by itself.)
a. What is a shallow focus earthquake?
b. What is an epicenter?
c. Make observations regarding the shallow
focus earthquake distribution.
Observations should pertain ONLY to the
information being viewed on the figure. Do
not make interpretations as to why the
epicenters are distributed as they are.
d. Is the concentration of these epicenters
the same everywhere?
3. Slide 3 – “Overlay of shallow focus earthquake
epicenter on the seafloor physiography.”
(Overlay Figure 2 onto Figure 1. You may wish
Note that there are no student sheets with this
activity, as it is done as a class, with the teacher
leading the guided inquiry. Students should write
their observations and responses to the questions
posed by the teacher in their science notebooks.
to tape the edges of the overheads to the
projector, but this is only temporary.)
a.
Where are the greatest concentrations of
shallow focus earthquakes?
b. With what type of seafloor feature are
they associated?
Students are asked to make observations. Stress
that observations are what they can see, not the
how or why of the data presented. They should not
interpret the data (e.g., explain why volcanoes are in
a ring around the Pacific) when asked to make
observations.
4. Slide 4 – “Distribution of deep focus earthquake
epicenters.”
(Remove Figures 1 and 2 from the overhead
COASTeam Program, Project Oceanica, College of Charleston
2
Ring of Fire and Quakes
TEACHER PAGES
projector. Show Figure 3 by itself. Separate
Figures 1 and 2 if they were taped together.)
c.
Are they associated with any continental
features?
d. Generally, how are the volcanoes distributed
in the Pacific Ocean?
The line of volcanoes around the rim of the
Pacific is called the “Ring of Fire.”
e. Generally, how are the volcanoes distributed
in the Atlantic Ocean? Is there a “Ring of
Fire” in the Atlantic Ocean?
a. What is a deep focus earthquake?
b. Make observations (not interpretations)
regarding the deep focus earthquake
epicenter distribution. (Note: observations
should pertain ONLY to the information
being viewed.)
5. Slide 5 – “Overlay of deep focus earthquake
epicenters on seafloor physiography.”
(Overlay Figure 3 onto Figure 1. You may wish
9. Slide 9 – “Distribution of shallow focus
earthquake epicenters and active volcanoes.”
to tape the edges of the overheads to the
projector, but this is only temporary.)
(Overlay Figure 2 on Figure 4.)
a.
a.
Where are the greatest concentrations of
deep focus earthquakes?
b. Are they associated with any seafloor
features?
c. Are they associated with any continental
features?
10. Slide 10 – “Distribution of deep focus
earthquake epicenters and active volcanoes.”
(Remove Figure 2, and overlay Figure 3 on
Figure 4.)
6. Slide 6 – “Distribution of shallow and deep focus
earthquake epicenters.”
a.
(Remove Figure 1. Overlay Figure 3 onto Figure
2).
a.
Make observations to compare the
distribution of shallow focus earthquakes to
the distribution of deep focus earthquakes.
Make observations to compare the
distribution of deep focus earthquakes to
the distribution of recently active
volcanoes.
11. Slide 11 – “Distribution of shallow focus
earthquake epicenters, deep focus earthquake
epicenters, and active volcanoes.”
7. Slide 7 – “Distribution of recently active
volcanoes (approximated).”
(Add Figure 3 to Figures 2 and 4. Tape these
three overheads together, as they will be used
as a group in the next steps.)
(Remove Figures 2 and 3, and show Figure 4 by
itself.)
a.
Make observations to compare the
distribution of shallow focus earthquakes to
the distribution of recently active
volcanoes.
Make observations of the distribution of
active volcanoes.
a.
Summarize your observations regarding the
distributions of and associations among deep
and shallow focus earthquakes and
volcanoes.
b. Complete the following sentence: “Volcanoes
are more strongly associated with ____
focus earthquake epicenters.”
8. Slide 8 – “Overlay of recently active volcanoes
on seafloor physiography.”
(Overlay Figure 4 onto Figure 1.)
a.
Where are the greatest concentrations of
volcanoes?
b. Are they associated with any seafloor
features?
COASTeam Program, Project Oceanica, College of Charleston
3
Ring of Fire and Quakes
TEACHER PAGES
12. Slide 12 – “Overlay of shallow and deep focus
earthquake epicenters, and volcanoes on
seafloor physiography.”
14. Toggle back and forth between Slide 13 and
Slide 14 several times so that students can
visualize the associations among earthquakes,
volcanoes and the different types of plate
boundaries.
(Place Figure 1 underneath the taped stack of
Figures 2, 3, and 4).
(Overlay Figures 2,3, and 4 on Figure 5.)
a.
What earthquake/volcanic activity is
occurring at the mid-ocean ridges (e.g., the
Mid-Atlantic Ridge and East Pacific Rise)?
b. What earthquake/volcanic activity is
occurring at Iceland?
c. What earthquake/volcanic activity is
occurring at trenches (e.g., the Aleutian
Trench, the Mariana Trench, The Tonga
Trench, the Peru-Chile Trench)?
d. What earthquake/volcanic activity is
occurring at the Andes Mountains?
e. What earthquake/volcanic activity is
occurring at the seamount chains such as
the Aleutian Islands and the Mariana
Islands?
f. What earthquake/volcanic activity is
occurring at Hawaii?
g. What earthquake/volcanic activity is
occurring at the San Andreas Fault?
a.
What type or types of earthquakes do you
find associated with divergent plate
boundaries?
b. What type or types of earthquakes do you
find associated with convergent plate
boundaries?
c. Compare divergent and convergent plate
boundaries with respect to the distribution
and abundance of volcanoes.
d. Find the San Andreas Fault. What type of
plate boundary is it? What type or types of
earthquakes are associated with it?
e. Is Hawaii on a plate boundary? What type
or types of earthquakes are associated with
it?
15. Students should be challenged with the
following questions, which are intended to
provoke brainstorming. Students may be broken
into small discussion groups to devise some
hypotheses to answer the questions.
13. Slide 13 – “Tectonic plates, showing divergent,
convergent and transform plate boundaries.”
(Remove Figures 1-4 and show only Figure 5.)
What does a high concentration of earthquakes
occurring along a line indicate?
This figure shows the locations of the tectonic
plate boundaries. Examine the legend and make
observations as to where divergent, convergent
and transform plate boundaries occur.
a. Define the terms divergence, and
convergence.
b. What seafloor and/or continental feature(s)
are found associated with divergent plate
boundaries?
c. What seafloor and/or continental feature(s)
are found associated with convergent plate
boundaries?
d. Where is the largest transform plate
boundary on the Pacific Plate?
Deep focus earthquakes are usually not located
directly beneath the shallow focus earthquakes,
but they are almost always offset. Any ideas
why this might be occurring?
Most volcanoes occur above deep focus
earthquakes, rather than shallow focus
earthquakes. Is there a possible association
between these „quakes and volcanoes?
Why are there few to no deep focus
earthquakes associated with mid-ocean ridges?
COASTeam Program, Project Oceanica, College of Charleston
4
Ring of Fire and Quakes
TEACHER PAGES
Assessment
Use the students‟ responses to the previous
questions as assessment of their understanding
of the Ring of Fire and Quakes as well as the
relationship between plate boundaries and the
locations of earthquakes and volcanoes.
Source: Dr. Leslie Sautter, Project Oceanica, Dept. of Geology and Environmental Geosciences, College of Charleston, SC.
website: http://oceanica.cofc.edu email: [email protected] phone: 843-953-5586
Funding for the COASTeam Program was provided by the South Carolina Sea Grant Consortium. http://oceanica.cofc.edu/coasteam/
COASTeam Program, Project Oceanica, College of Charleston
5
Ring of Fire and Quakes
TEACHER PAGES
COASTeam Program, Project Oceanica, College of Charleston
6