At the end of what could only have been a miserable day, William Clark wrote in his journal:
“We made 22 Miles only to day the wind and a Strong current being
against us all day, with rain. Discovered a high mountain S E. Covered
with Snow which we call Mt. Jefferson.” It was March 30, 1806, and
Clark, Meriwether Lewis, and their Corps of Discovery had been on the
trail home for just five days after wintering near the Oregon coast.
They named the towering peak after Thomas Jefferson, the president who sent them west to explore the headwaters of the Missouri River and find a water route to the Pacific Ocean.
Mount Jefferson was one of five volcanic peaks that the Lewis and
Clark expedition observed rising over the Cascade Range during their
voyage down the Columbia River, and the only one they named. At 3,199
meters (10,495 feet) in elevation, Mount Jefferson ranks as the second
highest peak in Oregon.
This view of the volcano came from the Operational Land Imager on the Landsat 8
satellite on August 13, 2013. Even from above, the peak’s symmetrical
cone shape and glacier-capped height set it apart from the surrounding
mountains.
Mount Jefferson is a stratovolcano
that has erupted periodically over the past 300,000 years. The volcano
can produce large, explosive eruptions, and the last one was about
15,000 years ago. Smaller events have also occurred, including lava
flows and lahars. Some of the most recent activity associated occurred
about 7,600 years ago, when basaltic lava flowed from Forked Butte and
the North Cinder Peak south of Mount Jefferson down valleys carved out
by glaciers. These flows look like dark rivers in the lower half of the
image.
Much of Mount Jefferson’s history is unknown since erosion by
glaciers has long since erased the evidence of past eruptions. Even
today, the mountain is covered in glaciers, making it a significant challenge for climbers.
Though past activity may not be obvious, more recent disasters are.
The red-brown region northeast of Mount Jefferson is a burn scar from
the 2012 Waterfalls 2 fire. And treeless regions near the basalt flows are scars from the B&B complex fire.
The bright white glaciers and surrounding dark forest also make Mount
Jefferson a challenge for satellites. To see detail in the dark forest,
one would have to brighten the image enough that the ice would be
overly white and featureless. But darkening the image to see features in
the ice or clouds would obscure the forest. Providing detail on both
the bright and dark ends of the scale, this image represents the best
Landsat view to date. The Landsat 8 satellite is more sensitive to brightness and color than past Landsat satellites.
Since Landsat data are distributed free of charge through the U.S.
Geological Survey, anyone can produce a true-color Landsat 8 image using
image-editing software. To learn how the Earth Observatory team made
this image, see How to make a true-color Landsat 8 image. The blog post also provides information about how to download free data.
References
- Global Volcanism Program Jefferson. Accessed October 30, 2013.
- NASA Earth Observatory (2013, October 22) How to make a true-color Landsat 8 image. Elegant Figures, Robert Simmon. Accessed October 30, 2013.
- United States Geological Survey (2011, January 3) Mission of the Corps of Discovery and the U.S. Geological Survey. Accessed October 30, 2013.
- United States Geological Survey (2004, June 29) The volcanoes of Lewis and Clark: Mount Jefferson, Oregon. Accessed October 30, 2013.
- United States Geological Survey Cascades Volcano Observatory (2005, December 23) Mount Jefferson Volcano, Oregon. Accessed October 30, 2013.
NASA Earth Observatory image by Robert Simmon, using Landsat 8 data from the USGS Earth Explorer. Caption by Holli Riebeek.
- Instrument:
- Landsat 8 - OLI
NASA: USA - Mount Jefferson - 11.17.13
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My blogs are an open house to all cultures, religions and countries. Be a follower if you like it, with this action you are building a new culture of tolerance, open mind and heart for peace, love and human respect.
Thanks :)
Mis blogs son una casa abierta a todas las culturas, religiones y países. Se un seguidor si quieres, con esta acción usted está construyendo una nueva cultura de la tolerancia, la mente y el corazón abiertos para la paz, el amor y el respeto humano.
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