Earthquake!
The Stage
Idaho is part of the world’s longest mountain chain above sea level. This chain
extends from the tip of South America to Alaska’s north coast. The widest
section is in the western United States—from the Sierra Nevada to the Rocky
Mountains. The Lost River Range is one of many smaller mountain ranges
between the Rockies and the Sierra Nevadas.
The earth’s crust between the Sierra Nevada and Rocky Mountains, including
the Great Basin, is stretching about 1/2 inch per year. And, it’s getting thinner.
Every so often—a few hundred to a few thousand years—the crust breaks along
old fracture lines known as “faults.” The valleys drop and the mountains rise,
creating the “Basin and Range” landscape you see from here.
