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Available Weekly Reports
There are no Weekly Reports available for Crater Lake.
Summary of eruption dates and Volcanic Explosivity Indices (VEI).
|Start Date||Stop Date||Eruption Certainty||VEI||Evidence||Activity Area or Unit|
|2850 BCE (?)||Unknown||Confirmed||Radiocarbon (corrected)||Lava dome ENE of Wizard Island|
|5250 BCE (?)||Unknown||Confirmed||Tephrochronology||Wizard Island and Merriam Cone|
|5550 BCE (?)||Unknown||Confirmed||0||Tephrochronology||Central Platform|
|5677 Oct 15 BCE ± 150 years ± 45 days||Unknown||Confirmed||7||Ice Core||Mt. Mazama summit and flank vents|
|5900 BCE ± 50 years||Unknown||Confirmed||6||Radiocarbon (corrected)||North flank (Llao Rock)|
The following references are the sources used for data regarding this volcano. References are linked directly to our volcano data file. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title. Additional discussion of data sources can be found under Volcano Data Criteria.
Bacon C R, 1983. Eruptive history of Mount Mazama and Crater Lake caldera, Cascade Range, U S A. J Volc Geotherm Res, 18: 57-116.
Bacon C R, 2008. Geologic map of Mount Mazama and Crater Lake caldera, Oregon. U S Geol Surv Sci Invest Map, I-2832, 1:24,000 scale, 4 sheets and 45 p text.
Bacon C R, Druitt T H, 1988. Compositional evolution of the zoned calcalkaline magma chamber of Mount Mazama, Crater Lake, Oregon. Contr Mineral Petr, 98: 224-256.
Bacon C R, Lanphere M A, 2006. Eruptive history and geochronology of Mount Mazama and the Crater Lake region, Oregon. Geol Soc Amer Bull, 118: 1331-1359.
Green J, Short N M, 1971. Volcanic Landforms and Surface Features: a Photographic Atlas and Glossary. New York: Springer-Verlag, 519 p.
Hildreth W E, 2007. Quaternary magmatism in the Cascades--geologic perpectives. U S Geol Surv Prof Pap, 1744: 1-125.
Kamata H, Suzuk-Kamata K, Bacon C R, 1993. Deformation of the Wineglass Welded Tuff and the timing of caldera collapse at Crater Lake, Oregon. J Volc Geotherm Res, 56: 253-266.
Nelson C H, Bacon C R, Robinson S W, Adam D P, Bradbury J P, Barber J H Jr, Schwartz D, Vagenas G, 1994. The volcanic, sedimentologic, and paleolimnologic history of the Crater Lake caldera floor, Oregon: evidence for small caldera evolution. Geol Soc Amer Bull, 106: 684-704.
Sherrod D R, Smith J G, 1990. Quaternary extrusion rates of the Cascade Range, northwestern United States and southern British Columbia. J Geophys Res, 95: 19,465-19,474.
Williams H, 1942. The geology of Crater Lake National Park, Oregon. Carnegie Inst Wash Pub, 540: 1-162.
Zdanowicz C M, Zielinski G A, Germani M S, 1999. Mount Mazama eruption: calendrical age verified and atmospheric impact assessed. Geology, 27: 621-624.
The spectacular 8 x 10 km Crater Lake caldera in the southern Cascades of Oregon formed about 6850 years ago as a result of the collapse of a complex of overlapping shield and stratovolcanoes known as Mount Mazama. The cone-building stage, during which at least five andesitic and dacitic shields and stratovolcanoes were constructed, took place between about 420 and 40 thousand years ago (ka). A series of rhyodacitic lava domes and flows and associated pyroclastic rocks were erupted between about 30 ka and the climactic eruption. The explosive eruptions triggering collapse of the 8-10 km wide caldera about 7500 years ago were among Earth's largest known Holocene eruptions, distributing tephra as far away as Canada and producing pyroclastic flows that traveled 40 km from the volcano. A 5-km-wide ring fracture zone is thought to mark the original collapse diameter. The deep blue waters of North America's second deepest lake, at 600 m, fill the caldera to within 150-600 m of its rim. Post-caldera eruptions within a few hundred years of caldera formation constructed a series of small lava domes on the caldera floor, including the partially subaerial Wizard Island cinder cone, and the completely submerged Merriam Cone. The latest eruptions produced a small rhyodacitic lava dome beneath the lake surface east of Wizard Island about 4200 years ago.