ter Lake
Crater Lake is the deepest lake in the United States. The lake formed in the crater at the top of
volcanic Mount Mazama after it exploded in a violent eruption approximately 7700 years ago.
The rim of the crater is approximately 2300 meters (7500 feet) above sea level and is mostly
composed of the rock andesite. The average yearly air temperature at the lake is 38°F, and
snowfall often occurs from October through June. Hydrothermal activity (heating of the water) is
ongoing under the lake, indicating that this region is still volcanically active.
40° N
Pacific
Ocean
Wizard
Island A
WASHINGTON
OREGON
Crater
Lake
530
460
IDAHO
450 494
540
MONTANA
Yellowstone
Field Map of Crater Lake
-Crater rim-
500
550
Hot Spot
WYOMING
460 400
500
540
B
490
300
2001
N
100
40° N
500
570
560
560
500
460
lake bottom.
Determine the gradient, in meters per kilometer, between points C and D.
Kilometers what’s the gradient?