Crater Lake National Park is a United States National Park located in
Southern Oregon whose primary feature is Crater
Lake. It was established on May 22, 1902 as the fifth National Park in the U.S.[1] The park encompasses
Crater Lake's caldera, which rests in the remains of a destroyed volcano posthumously called Mount Mazama. The lake is 1,958 feet (597 m)
deep at its deepest point, which makes it the deepest lake in the United States and the seventh
deepest anywhere in the world. The caldera rim ranges in elevation from 7000 to 8000 feet (2100 to 2400 m). The average elevation
of the lake itself is 6178 ft (1883 m). The park covers 286 mi² (741 km²). Crater Lake has no streams flowing into or out of it.
The lake's water regularly has a striking blue hue.
Geology
-
Relief map of the Crater Lake area
Volcanic activity in the area is fed by subduction off the coast of Oregon as the
Juan de Fuca Plate slips below the North
American Plate (see plate tectonics). Heat and compression generated by this
movement has created a mountain chain topped by a series of volcanoes, which together are
called the Cascade Range. The large volcanoes in the range are called the High Cascades.
However, there are many other volcanoes in the range as well, most of which are much smaller.
About 400,000 years ago, Mount Mazama began life in much the same way as the other
mountains of the High Cascades, as overlapping shield volcanoes. Over time, alternating
layers of lava flows and pyroclastic flows built Mazama's
overlapping cones until it reached about 11000 feet (3400 m) in height.
As the young stratovolcano grew, many smaller volcanoes and volcanic vents were built
in the area of the park and just outside what are now the park's borders. Chief among these were cinder cones. Although the early examples are gone—cinder cones erode
easily—there are at least 13 much younger cinder cones in the park, and at least another 11 or so outside its borders, that still
retain their distinctive cinder cone appearance. There continues to be debate as to whether these minor volcanoes and vents were
parasitic to Mazama's magma chamber and system or if they were related to background
Oregon Cascade volcanism.
After a period of dormancy, Mazama became active again. Then, around 4860 BC, Mazama collapsed into itself during a tremendous
volcanic eruption, losing 2500 to 3500 feet (760 to 1100 m) in height. The eruption formed a
large caldera that was later filled with a deep blue lake known today as Crater Lake.
The eruptive period that decapitated Mazama also laid waste to much of the greater Crater Lake area and deposited
ash as far east as the northwest corner of what is now Yellowstone National Park, as far south as central Nevada, and
as far north as southern British Columbia. It produced more than 150 times as much ash
as the May 18, 1980 eruption of Mount St.
Helens.
Park features
An aerial view of Crater Lake
Some notable park features created by this huge eruption are:
- The Pumice Desert: A very thick layer of pumice and ash leading away from Mazama in a
northerly direction. Even after thousands of years, this area is largely devoid of plants due to
excessive porosity (meaning water drains through quickly) and poor
soil composed primarily of regolith.
- The Pinnacles: When the very hot ash and pumice came to rest near the volcano, it formed 200 to 300-foot (60 to 90 m) thick
gas-charged deposits. For perhaps years afterward, hot gas moved to the surface and slowly cemented
ash and pumice together in channels and escaped through fumaroles. Erosion later removed most of the surrounding loose ash and pumice, leaving tall pinnacles and spires.
Other park features:
- Mount Scott is a steep andesitic cone whose lava came from
magma from Mazama's magma chamber; geologists call such
volcano a "parasitic" or "satellite" cone. Volcanic eruptions apparently ceased on Scott sometime before the end of the
Pleistocene; one remaining large cirque on Scott's northwest
side was left unmodified by post-ice age volcanism.
- In the southwest corner of the park stands Union Peak, an extinct volcano whose primary remains consist of a large volcanic
plug, which is lava that solidified in the volcano's neck.
- Crater Peak is a shield volcano primarily made of andesite and basalt lava flows topped by andesitic and dacite tephra.
- Timber Crater is a shield volcano located in the northeast corner of the park. Like Crater Peak, it is made of basaltic and
andesitic lava flows, but, unlike Crater, it is topped by two cinder cones.
- Rim Drive is the most popular road in the park; it follows a scenic route around the caldera
rim.
History
Another aerial view of Crater Lake
Local Native Americans witnessed the collapse of
Mount Mazama and kept the event alive in their legends. One
ancient legend of the Klamath people closely parallels the geologic story which emerges from
today's scientific research. The legend tells of two Chiefs, Llao of the Below World and
Skell of the Above World, pitted in a battle which ended up in the destruction of Llao's home, Mt.
Mazama.[2] The battle was witnessed in the eruption of Mt.
Mazama and the creation of Crater Lake.
The first known European American to visit the lake were a trio of gold prospectors: John Wesley Hillman, Henry Klippel, and Issac
Skeeters who, on June 12, 1853, stumbled upon the long, sloping
mountain while looking for a lost mine. Stunned by vibrant blue color of the lake, they named the
indigo body of water "Deep Blue Lake" and the place on the southwest side of the rim where he
first saw the lake later became known as Discovery Point.[1] But gold was more on the minds of settlers at the time and the discovery was soon forgotten. The
suggested name later fell out of favor by locals, who preferred the name Crater Lake, although crater is a misnomer[citation needed] because the lake's basin is in fact a caldera, a volcanic feature that forms from subsidence, not from excavation.
William Gladstone Steel devoted his life and fortune to the establishment and
management of a national park (US) at Crater Lake. His preoccupation with the lake began in 1870.
In his efforts to bring recognition to the park, he participated in lake surveys that provided scientific support. He named many
of the lake's landmarks, including Wizard Island, Llao Rock, and Skell Head.
With the help of geologist Clarence Dutton, Steel organized a USGS
expedition to study the lake in 1886. The party carried the Cleetwood, a half-ton survey boat, up the steep slopes of the
mountain then lowered it to the lake. From the stern of the Cleetwood, a piece of pipe on the end of a spool of
piano wire sounded the depth of the lake at 168 different points. Their deepest sounding,
1,996 feet, was very close to the modern official depth of 1,932 feet (made in 1953 by sonar).[1] At the same time, a
topographer surveyed the area and created the first professional
map of the Crater Lake area.
Partly based on data from the expedition and lobbying from Steel and others, Crater Lake National Park was established
May 22, 1902 by President Theodore Roosevelt. And because of Steel's involvement, Crater Lake Lodge was opened in 1915 and the
Rim Drive was completed in 1918.[1]
Highways were later built to the park to help facilitate visitation. The 1929 edition of
O Ranger! described access and facilities available by then:
| “ |
Crater Lake National Park is reached by train on the Southern Pacific Railroad lines into Medford and
Klamath Falls, at which stops motor stages make the
short trip to the park. A hotel on the rim of the lake offers accommodations. For the motorist, the visit to the park is a short
side trip from the Pacific and Dalles-California
highways. He will find, in addition to the hotel, campsites, stores, filling stations.
The park is open to travel from late June or July 1 for as long as snow does not block the roads, generally until
October.[3] |
” |
Activities
There are many hiking trails inside the park, and several campgrounds. Unlicensed fishing is
allowed without limitation of size, species or number. The lake is believed to have no indigenous fish, but were introduced
beginning in 1888 until fish stocking ended in 1941. Kokanee Salmon (Oncorhynchus nerka) and Rainbow Trout
(Oncorhynchus mykiss) now thrive naturally.[4]
Swimming is allowed in the lake, and boat tours operate daily during the summer which stops at Wizard Island, a cinder cone inside the lake. All lake access is from Cleatwood Trail, a steep walking
trail.
Observation points along the caldera rim are easily accessible by car via Rim Drive, which
is 33 miles (53 km) in length and has an elevation gain of 3800 feet (1158 m).
The highest point in the park is Mt. Scott, 8929 feet (2721 m). Getting there
requires a fairly steep 2.5 mile (4 km) hike from the Rim Drive trailhead. On a clear day from Mt. Scott's summit, visibility
exceeds 100 miles (160 km) and can, in one single view, take in the entire caldera. Also visible from this point are the white
peaked High Cascade volcanoes to the north, the
Columbia River Plateau to the east, and the Western Cascades and the more distant
Klamath Mountains to the west.
Crater Lake's features are fully accessible during the summer months: heavy snow in the park during the fall, winter, and
spring forces road and trail closures, including popular Rim Drive (which is generally open from July to October).
See also
References
Satellite view of Crater Lake
- Rick Harmon, Crater Lake National Park: A History (Corvallis: Oregon State University Press, 2002). ISBN
0-87071-537-2
- Stephen L. Harris, Fire Mountains of the West: The Cascade and Mono Lake Volcanoes (Missoula: Mountain Press
Publishing Company, 1988). ISBN 0-87842-220-X
- Ann G. Harris, Esther Tuttle, Sherwood D. Tuttle, Geology of National Parks: Fifth Edition (Iowa: Kendall/Hunt
Publishing, 1997). ISBN 0-7872-5353-7
External links
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