Geology of Urban Watersheds - Urban Watersheds: Geology, Contamination, and Sustainable Development - page 24

Eurasian Plate Eurasian Plate

North American Plate

CASCADE
-RANGE
-San Andreas
Fault

Aleutian Trench

Mid-Atlantic
Ridge

“ Ring of Fire ”

Arabian
Plate

Hawaiian “Hot Spot”

Cocos Plate

East Pacific
Rise-

Java Trench-

Nazca
Plate

South
American
Plate

African Plate

Indo-Australian Plate

Pacific Plate

Antarctic Plate

USGS

FIGURE 2.1
The major tectonic plates of the world. (From United States Geological Survey, World map showing plate bound-
aries and active volcanoes, http://vulcan.wr.usgs.gov/Glossary/PlateTectonics/Maps/map_plate_tectonics_
world.html (accessed June 18, 2010), 2010a.)

Exosphere

Thermosphere

Atmosphere

Mesosphere

Stratosphere

Lithosphere
(crust and upper
most solid mantle)

Troposphere

Crust 0-100 km
thick

Asthenosphere

Mantle

Mantle

Crust

2900 km

Not to scale

Liquid

Core

Outer core

5100 km

Solid

Inner core

6,378 km

To scale

FIGURE 2.2
(See color insert.) Cross section of the interior portions of the Earth showing the asthenosphere. (Modified
from Kious, W.J. and Tilling, R.I., The Dynamic Earth: The Story of Plate Tectonics, United States Geological Survey,
Governmental Printing Office, Washington, DC, 1996.)