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Chaos Crags

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Chaos Crags
Chaos Crags with Chaos Jumbles below.
Highest point
Elevation8,124+ ft (2,476+ m) NAVD 88[1]
Prominence~ 580 ft (177 m)
Geography
Map
LocationLassen Volcanic National Park, Shasta County, California, U.S.
Parent rangeCascade Range
Topo mapUSGS Manzanita Lake
Geology
Age of rockHolocene
Mountain typeLava domes[3]
Volcanic arcCascade Volcanic Arc[4]
Last eruption980 CE ± 300 years
Climbing
Easiest routeScrambling

Chaos Crags is the youngest group of lava domes in Lassen Volcanic National Park, California, having been formed as five dacite domes 1,100-1,000 years ago.[5] The cluster of domes is located north of Lassen Peak.

From the base of the crags and extending toward the northwest corner of the park is Chaos Jumbles, a cold rock avalanche which undermined Chaos Crags' northwest slope 300 years ago.[6] Riding on a cushion of compressed air (see sturzstrom), the rock debris traveled at about 100 miles per hour (160 km/h), flattened the forest before it, and dammed Manzanita Creek, forming Manzanita Lake.

In 1974 the National Park Service took the advice of the USGS and closed the visitor center and accommodations at Manzanita Lake. The USGS stated that these buildings would be in the way of a rockslide from Chaos Crags if an earthquake or volcanic eruption occurred in the area.

In 2011, twenty prefab cabins were reinstalled in the Manzanita Lake Campground. It had been determined in the 1980s that the rockslide danger had been overstated by the USGS, and therefore, the cabins were reintroduced to the park for nightly rental.[7]

Chaos Crags and Lassen Peak seen from the side of Manzanita Lake

References

  1. ^ "Chaos Crags, California". Peakbagger.com. Retrieved 2014-12-28.
  2. ^ "Chaos Crags". Geographic Names Information System. United States Geological Survey, United States Department of the Interior. Retrieved 2014-12-28.
  3. ^ "Lassen Volcanic Center - Synonyms and Subfeatures". Global Volcanism Program. Smithsonian Institution. Retrieved 2009-01-05.
  4. ^ "Lassen Volcanic Center". Global Volcanism Program. Smithsonian Institution. Retrieved 2009-01-05.
  5. ^ Wood, Charles A.; Jűrgen Kienle (1993). Volcanoes of North America. Cambridge University Press. pp. 216–219. ISBN 0-521-43811-X.
  6. ^ Hill, Richard L. (2004-10-01). Volcanoes of the Cascades: Their Rise and Their Risks. Falcon. pp. 86–87. ISBN 978-0-7627-3072-8.
  7. ^ http://www.redding.com/news/lassen-park-brings-back-manzanita-lake-cabins

Further reading

  • Ann G. Harris; Esther Tuttle; Sherwood D. Tuttle (1997). Geology of National Parks, Fifth edition. Iowa: Kendall/Hunt Publishing. ISBN 0-7872-5353-7.
  • CVO Description - Lassen Peak (Look under Lassen Volcanic National Park - Points of Interest for info on Chaos Crags in that site)