In this activity, you will use Google Earth to study the characteristics of volcanoes. You will then try to
determine the type of volcano, based on what you have observed.
Begin by opening Google Earth. You will need to make sure that all of your measurements are metric.
To do this, go to the “Tools” tab and select “Options.” Click the “3D View” category, and choose “Meter,
Kilometers” in the “Show Elevation” box. You will also need to select “Decimal Degrees” in the “Show
Lat/Long” box. See the picture below for more detail.
You will be assigned two volcanoes to investigate using Google Earth. Type your volcano’s latitude and
longitude into the “Fly To” search section on the left side of the screen. Once you locate your volcano
(it may be helpful to zoom out a bit), label its position on the map with a “placemark” by clicking on the
thumbtack icon. This will make it easier to go back to your volcano if you need additional information.
At times, it may be helpful to view your volcano’s profile instead of an aerial view. To tilt the image of
the volcano, use the “Look Joystick” in the top right-hand corner of the screen. Pressing the “up” arrow
in the “Look Joystick” tilts the view from a top-down view to one that is parallel with the surface of the
Earth, allowing you to see a side view of the volcano.
My assigned volcanoes are:
For each of your volcanoes, please measure the following and record the data in the data table on page
3. You will then transfer the information for your volcanoes to a Google Doc. The link for the Google
doc can be found on Mrs. Boykin’s wiki page: boykinhonors.wiki.cvsd.k12.pa.us .
The surface elevation at the location of the cursor is provided at the bottom of the screen in Google
Earth. Use this reading to measure the height of your volcano in meters at the summit and the lower
flanks of your volcano. The summit is the highest point on your volcano. The lower flank is where the
slope flattens out into level ground. Record the elevation in the data table.
Note: You can estimate the elevation at several locations, both at the summit and on the flank, before
deciding which measurements are most accurate!
A volcano’s relief is the difference between the summit elevation and the elevation of the lower flanks.
Calculate your volcano’s relief and record it on the data table.
Relief = Summit elevation – lower flanks elevation
The radius of the volcano is a measure of how wide a volcano is. It is the distance from the middle of
the volcano, marked by the summit, to the lower flanks of the volcano, or where the volcano’s slope
flattens out. To measure the radius of your volcano, click on the ruler tool located at the top of the
window. Change the measuring unit to meters, and click to draw a line reaching from the summit to the
lower flanks. Record your data in the data table.
One way to calculate the slope of the volcano is to use your data and a calculator to determine slope
with trigonometry. Use the relief (A) and radius (B) from the data table to calculate the slope of the
volcano’s flank. First, determine the value of A/B and then find the slope by calculating the following:
Slope = tan-1 (A/B)
See Mrs. Boykin if you need help putting this into your calculator,
or for alternate way of calculating this.
A color index is a measure of the dark minerals/materials in a rock. Dark minerals/materials (basalt) are
called mafic by geologists. Mafic magma tends to erupt non-violently. Geologists call light minerals
(rhyolite) felsic. Felsic magma tends to erupt violently. Intermediate magmas behave both ways.
Use the color index chart provided by Mrs. Boykin (or view it on the Wiki site) to estimate if your rocks
are light, intermediate, or dark in color. Hold the chart against the appropriate part of the computer
screen. Record the percentage for the color index in the data table.
Study the appearance of your volcanoes using Google Earth. Details that can be observed from the
surface of the volcano and surrounding area can provide hints about the nature of the volcano.
Possible things to include in your observations:
Do you observe glowing lava or an ash plume?
Were there any problems that might cause your data to be inaccurate (ex. Cloud cover)?
Is there any evidence of lava flows or gas?
Is there any vegetation near the summit?
Put your information for your assigned volcanoes into the chart below. When you have completely filled
out the chart, copy your data into the “Volcano Google Earth” Google Doc. The link to this Google Doc
can be found on Mrs. Boykin’s wiki page.
Elevation Radius Slope
Lower (m) Color Other Volcano
Volcano Summit (B) (degrees)
flanks (summit- Index Observations Type
Plot the data from the volcanoes you researched on the graph displayed on the Promethean Board.
Label your volcano by using the first 3 letters of the volcano’s name. This graph will examine size
relationships among volcano types.
Questions: Answer the following questions for each of your assigned volcanoes.
1. Are the upper slopes showing barren rock or vegetation? What is the significance of this?
2. Are there any nearby towns and cities?
3. Are there any natural or manmade features that might lessen the damage from an eruption?
4. What is the most interesting thing you saw when examining your volcanoes?
Graphing your volcanoes to scale:
Obtain a piece of graph paper from the front table. Complete the following steps for each of your
1. Select an appropriate scale for your volcano. I suggest you use a scale of 1 cm = 200 m.
2. Graph a point to represent the outer flanks of the volcano on your graph paper. Using your
scale, move horizontally, a graph another point at the distance representing the radius of the
volcano, which was recorded in your data table.
3. Connect these two points with a line.
4. Use a protractor to draw an angle equal to the slope of the volcano. Extend the line from this
angle to the point where it lies directly above the radius of the volcano (at the summit).
If any time remains, go back to the Google Doc and check out your classmates’ observations. Check out
any volcanoes that sound interesting to you.