Crater Lake Facts: The Science of Crater Lake National Park Oregon
Nestled in the center of southern Oregon’s wilderness and national forest lands lies the world’s 7th deepest freshwater lake, a gaping basin filled with centuries of rain and snowfall of unmatched clarity and color. Crater Lake is the main feature of Crater Lake National Park and no streams enter or leave it. Its pristine waters thus remain unclouded by sediment and consistent levels are maintained by a delicate balance of rain, snowfall, evaporation and seepage. It is estimated that precipitation compensates for water lost from evaporation and seepage at a rate such that the total amount of water is replaced every 250 years.
Why is Crater Lake so blue?
In contrast to red light, which is absorbed near the surface of the water and converted into heat, or yellow light, which is absorbed slightly deeper than the red, blue light travels to great depths before causing electrons in the water molecules to vibrate and re-radiate light in blue wavelengths. Therefore, although sunlight entering Crater Lake’s crystal-clear waters contains a variety of colors, these colors are absorbed by the lake’s great depth and the human eye only sees the remaining wavelengths of scattered blue light.
Was it formed by a meteor?
No. Crater lake lies in the enormous, bowl-shaped belly (or caldera) of Mount Mazama, one of a long line of Cascade range volcanos stretching from northern California into British Columbia. Two of the Earth’s crustal plates, the oceanic crust and the continental plate collide along this zone. As the oceanic crust’s denser plate is forced beneath the continental plate, it meets powerful temperatures and pressures that partially melt solid rock. Approximately 7 million years ago, the molten rock surfaced as volcanic vents, thus beginning the rise of the Cascade Range. This process continues today with both Lassen Peak and Mount Saint Helens having erupted within the last century.
How did a mountain become the nation’s deepest lake?
The 12,000-foot (3,600 meter) Mount Mazama was formed over a period of about 400,000 years by means of repeated volcanic eruptions. Glaciers formed and receded, while the mountain’s vents continued to emanate thick lava and put on spectacular displays of thinner lava bursting to the surface.
Then, about 7,700 years ago, a vent located northeast of the summit, commenced the most violent of Mount Mazama’s eruptions. The rising magma, under great pressure in a chamber below the mountain, released expanding gas which powered a huge skyward eruption of pumice and ash. New vents surrounding the crumpling peak formed and sent sizzling streams of pumice, ash, and gas oozing down its sides. As the pressurized magma chamber below it emptied, Mount Mazama could no longer support itself. Unable to bear its own weight, the once snow-capped volcano collapsed to form a deep caldera. This eruption may have been the most massive in North America in over 640,000 years and the resulting volcanic basin now holds 4.9 trillion gallons of water which geologists estimate took approximately 800 years of precipitation to fill.
How big is Crater Lake?
• 6.02 miles (9.69 kilometers) across (maximum)
• 4.54 miles (7.31 kilometers) across (minimum)
• 1,943 feet (592.23 meters) deep at deepest point
• Holds 4.9 trillion gallons (1.85e13 liters) of water
• Tallest point on rim 1,978 feet (602.89 meters) above lake
• Lower point on rim 507 feet (154.53 meters) above lake
The volcanic islands.
Crater Lake encapsulates two fascinating above-water landmasses: Wizard Island and Phantom Ship Island.
Rising 763 feet above the west end of Crater Lake, the volcanic cinder cone dubbed Wizard Island erupted about 7,300 years ago, after the lake began to fill with water. A symmetrical cinder cone capped by a volcanic crater named the “Witches Cauldron”, Wizard Island is almost wholly surrounded by dark, rugged lava flows. Although a number of cinder cones on the caldera floor were formed by smaller eruptions over the several hundred years following Mount Mazama’s explosion, Wizard Island is the only one to rise above the lake’s current water level.
Formerly part of the 400,000 year old “Phanton Cone” formation, a precursor to Mount Mazama and the first major volcano to erupt in its vicinity, Phantom Ship Island is the oldest exposed rock within the caldera. Composed of erosion-resistant lava, Phantom Ship Island is home to seven different species of trees, colonies of violet green swallows and several varieties of flowers and lichens.
The whitebark pine trees.
Able to withstand extreme temperatures and treacherous wind conditions, the whitebark pines at Crater Lake National Park live at the highest elevations and rely almost entirely on the Clark’s nutcrackers for regeneration. These smallish, ashy-grey birds derive their name from the explorer William Clark and are sometimes referred to as Clark’s Crow or Woodpecker Crow. They crack open the whitebark pine cones to feed on their fresh seeds. leaving seeds behind to germinate in the process, thus planting new trees and allowing the survival of these gnarled and twisted pines. Like many unfortunate pine trees throughout the West, the witebark pine has in recent years become a major target of the destructive mountain pine beetle, which constitutes the primary cause of whitebark pine mortality at Crater Lake.
The future of Crater Lake.
Mount Mazama is alive, well, and by no means an extinct volcano. Although currently asleep, Mount Mazana may one day awaken with a new phase of volcanic eruptions, returning this peaceful landscape to its powerful, violent past . As the geologic processes that formed the Cascade Range continue, future eruptions stand to destroy Crater Lake, filling the caldera with new rock. So check out this Oregon Bog Spot before it becomes a bubbling mess of red hot lava and ash.