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Data from the Global Volcanism Program of the Smithsonian Institution
Details for: Jefferson
Volcanic activity at glacially eroded Mount Jefferson, Oregon's second highest peak, ended during the Pleistocene. However, scoria cones south of the volcano have been active as recently as about 1,000 years ago. The extensive Whitewater Glacier in the foreground has eroded deeply into the volcano across the E flank. Photo by Willie Scott, 1981 (U.S. Geological Survey).
Volcano Number:
322020
Volcano Name:
Jefferson
Country:
United States
Volcano Type:
Stratovolcano
Last Eruption:
950 CE
Elevation:
3199m
Tectonic Setting:
Subduction zone / Continental crust (> 25 km)
Pop. within 30km:
823
Pop. within 100km:
556054
Latitude:
44.674
Longitude:
-121.8
Details
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Mount Jefferson, Oregon's second highest peak, is a deeply eroded stratovolcano. The glacier-clad landmark prominent from both sides of the Cascade Range was named by Lewis and Clark for the president that sponsored their expedition. Jefferson was constructed in two episodes interrupted by extensive glacial erosion. The first of these, beginning about 290,000 years ago, produced an andesitic-to-dacitic volcano possibly higher than the current summit. Dacitic lava domes were emplaced during a second cycle beginning about 70,000 years ago which included ash flows that traveled 15 km E and W. Several Holocene cinder cones near the Cascade crest south of Jefferson have produced lava flows that traveled down glacially carved valleys, including those from Forked Butte and North Cinder Peak. The most recent eruption, from a cinder cone on the flank of the South Cinder Peak cone, produced a lava flow that traveled west into Marion Lake about 1,000 years ago.
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Eruption Data from the Global Volcanism Program of the Smithsonian Institution
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Emissions Data from the Global Volcanism Program of the Smithsonian Institution
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Data from the Earthchem Library
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Data from the Earthchem Portal
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Data from the SESAR Database
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Data from the MaGa Database
Sorry. No data exist for this volcano in the MaGa database.
Data from UNAVCO
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Data from USIEI
Sorry. This volcano is not covered by any USIEI projects
Data from IRIS FDSNWS
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