By Neal Lineback and Mandy Lineback Gritzner, Geography in the NewsTM
Crater Lake: An Awesome Volcanic Wonder
Crater Lake is a beautiful caldera lake found in South-central Oregon State, USA. It has a stunning deep blue color and brilliant water clarity and forms the main feature in Crater Lake National Park. The lake is one of the purest bodies of water in the United States, with almost no signs of pollution and a record clarity of 43.3 meters.
National Parks are always major attractions to vacationers. Even as we endure the cold and snowy weather at the end of this 2014 winter, many are planning family road trips to the Northwest. Every summer thousands visit Crater Lake National Park, one of the West’s most awe-inspiring parks and home to the deepest lake in the United States.
Crater Lake is located 100 miles (160 km) east of the Pacific Ocean on the crest of the Cascade Mountain Range in Southern Oregon. The Cascades, as the massive volcanic range is known, extend from British Columbia, Canada, to northern California. The range continues to be active as the Juan de Fuca tectonic plate, located offshore in the Pacific, plunges beneath the North American plate, creating volcanic activity.
At 1,958 feet (597 m) deep, Crater Lake is the country’s deepest lake and the world’s seventh deepest lake. Crater Lake itself was created when the 12,000-foot (3,700-m) composite volcano Mount Mazama erupted approximately 7,700 years ago. The eruption collapsed the volcano’s top, leaving a depression called a caldera. Today, Crater Lake fills that caldera.
Mount Mazama’s eruption is the largest known eruption from the Cascade’s volcanoes, completely devastating the surrounding landscape. The volcano sent torrents of pumice and ash into all of the nearby river valleys and as far as 40 miles (64 km) from the eruption. Mount Mazama also discharged a blanket of ash to its northeast, reaching central Canada. According to the United States Geological Survey (USGS), scientists have even discovered tiny particles of ash from Mazama in Greenland’s ancient ice.
Following Mount Mazama’s collapse, which volcanologists believe took only a few hours or days to occur, the caldera continued filling with lava and rock debris from the caldera’s walls. Estimates show that it took 250 years of snow and rain from the time of Mazama’s eruption to fill the caldera with water to form what is today Crater Lake.
Crater Lake has no substantial inlets or outlets, relying solely on winter snows and any rain that falls for its water supply. On average, 533 inches (1,354 cm) of snow (equivalent to about 53 inches or 135 cm of water) falls in the area annually. Without natural major inlets, Crater Lake’s water has some of the lowest levels of pollutants in North America.
Crater Lake’s water level fluctuates only slightly from year to year, with a maximum observed variation of only 16 feet (5 m)—a minor change for such a deep lake, according to USGS. The small variations in lake levels are attributed to evaporation and seepage of the lake’s water, thus preventing major changes in water level.
Any volcanic activity at Crater Lake since Mazama’s initial eruption occurred within the caldera itself, including several smaller and less violent eruptions. Wizard Island, a small volcanic island on the west side of Crater Lake, was created during one of these events. Actually a cinder cone rising 760 feet (233 m) above the lake level, Wizard Island has a small crater at its summit. The crater remains dry during the summer months, but is filled by snowmelt during the spring.
As the eruption story is found in many ancient legends of the area, anthropologists believe that Native Americans witnessed Mount Mazama’s eruption more than 7,000 years ago. The first recorded sighting of Crater Lake by non-Native Americans occurred in 1853, when a group of prospectors “discovered” it while searching for a rumored lost gold mine. One of the prospectors called it “…the bluest lake he’d ever seen.” Crater Lake, while not receiving its current name until 1869, soon became legendary.
President Theodore Roosevelt gave Crater Lake and its surrounding landscape national park status in 1902. In total, Crater Lake National Park encompasses 249 square miles (645 sq. km). With stunning natural scenery and the spectacular crystal blue waters of its famous lake, Crater Lake National Park is worthy of repeated visits by vacationers.
And that is Geography in the News.
Sources: GITN 1135 Awesome Crater Lake: a Volcanic Marvel, Maps.com, Aug. 24, 2012; GITN #1106, “Mount St. Helens: 31 Years Later,” Maps.com, Aug. 12, 2011; http://vulcan.wr.usgs.gov/Volcanoes/CraterLake/description_crater_lake.html ; and http://www.nps.gov/crla/index.htm
Co-authors are Neal Lineback, Appalachian State University Professor Emeritus of Geography, and Geographer Mandy Lineback Gritzner. University News Director Jane Nicholson serves as technical editor. Geography in the NewsTM is solely owned and operated by Neal Lineback for the purpose of providing geographic education to readers worldwide.