Environmental Science, 10th Edition (Cunningham)

Chapter 14: Geology and Earth Resources

GE Exercise: Mount St. Helens

<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=jpg::::/sites/dl/free/8888888555/484165/google.jpg','popWin', 'width=210,height=178,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (34.0K)</a>

Take a virtual field trip with Google Earth!
Google Earth is a free, online application that uses satellite imagery to allow the user to zoom across the globe in a realistic, virtual environment. Downloading Google Earth is free at http://www.earth.google.com.

An overview manual is available by clicking here... Google Earth Overview (342.0K)

To continue:
- Make sure you have the Google Earth software installed and running.
- Copy the following latitude and longitude and paste into the "Fly to" field under the Search tab.
- Hit "Enter" for Google Earth to take you to the specified coordinates, then come back here and read the following overview.

Latitude/Longitude: 46.1895, -122.188

Overview: Mount St. Helens, p. 318

When this volcano erupted on May 18, 1980, it was the deadliest and most economically destructive volcanic event in the recorded history of the United States. Fifty-seven people were killed; and 250 homes, 46 bridges, 25 km of railroad track, and about 300 km of highway were destroyed. The eruption caused a massive debris avalanche to roll down the mountain's slopes. Before the eruption, the mountain was a smoothly symmetrical peak rising to more than 2,950 m (about 9,677 ft) above sea level. Spirit Lake at the foot of the mountain's west side was a much beloved vacation and fishing spot.

The eruption blew out the west side of the mountain, lowering the summit by about 400 m and depositing nearly 1 km3 of dust, ash, and volcanic rock on the surrounding land. You can see the horseshoe-shaped crater and a new central cone forming as lava and ash continue to emerge from the volcano. The catastrophic blast that ruptured the wall of the mountain created hurricane-force winds that flattened thousands of ha of forest. Ash spread over millions of ha of seven western states. Fortunately, the eruption was preceded by numerous earthquakes and a measurable bulge that developed on the mountain's flank. This gave most local residents ample warning to evacuate the area.

Try flying around the mountain using the compass rose in the upper right corner of your screen to get a bird's-eye view of the post-eruption shape of the volcano.

1
What is the white material inside the volcano's crater?
A)Crystals
B)Solidified ash
C)Calcium
D)Paint
E)Snow
2
How can snow persist on top of molten lava?
A)It's a rare example of "warm snow."
B)The molten lava and hot ash are now buried deep in the volcano (when it erupts again, the snow will melt).
C)A thin layer of cooled lava separates them.
D)The bottom layer of snow evaporates and refreezes on the top, in a continual cycle.
3
Why was the direction of the eruption and ash fall fortunate for Portland?
A)The ash provided an excellent fertilizer for acres of farmland.
B)It destroyed a controversial development, saving millions of dollars.
C)The eruption and ash fall were to the northeast, away from Portland
D)It stimulated the economy by providing an area for the study of volcanoes
E)Because that is where they had built the moat to slow down the lava.
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