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Posts tagged Cascade Volcanic Arc

Mount Hood and Lake Bonneville, Western USA – May 9th, 2010

45.5N 121.5W

May 9th, 2010 Category: Image of the day, Rivers, Volcanoes

USA - April 28th, 2010

USA - April 28th, 2010

Mount Hood, standing out above the surrounding peaks of the Cascade Range in the lower right quadrant of this orthorectified image, is a stratovolcano in the Cascade Volcanic Arc of northern Oregon. It is located about 50 miles (80 km) east-southeast of Portland, on the border between Clackamas and Hood River counties.

The exact height assigned to Mount Hood’s snow-covered peak has varied over its history. Modern sources point to different heights: 11,249 feet (3,429 m) based on the 1991 U.S. National Geodetic Survey and 11,240 feet (3,426 m) based on a 1993 scientific expedition. Regardless, it is the highest mountain in Oregon and the fourth-highest in the Cascade Range.

Visible to the north of the volcano is Lake Bonneville, a reservoir on the Columbia River shared by the U.S. states of Oregon (south) and Washington (north). It was created in 1937 with the construction of Bonneville Dam. The reservoir stretches between it and the Dalles Dam, upstream. It lies in parts of three counties in Oregon (Multnomah, Hood River, Wasco) and two in Washington (Skamania, Klickitat).

Mount Shasta and Surrounding Volcanic Peaks, California USA

41.3N 122.3W

July 29th, 2009 Category: Volcanoes

USA - July 16th, 2009

USA - July 16th, 2009

A series of volcanoes are visible in this orthorectified image, the most prominent of which is Mount Shasta, in the top left corner. Mount Shasta is a stratovolcano and the second-highest peak in the Cascade Range, at 14,179 feet (4,322 m).

The mountain consists of four overlapping volcanic cones which have built a complex shape, including the main summit. What remains of the oldest of Shasta’s four cones is exposed at Sargents Ridge on the south side of the mountain. Lava from the Sargents Ridge vent covers the Everitt Hill shield at Shasta’s southern foot.

The newest and highest cone is called the Hotlum Cone, named after the Hotlum glacier on its northern face; its longest lava flow, the 500 feet (150 m) thick Military Pass flow, extends 5.5 miles (8.9 km) down its northwest face.

One prominent cone, Shastina, is a 12,330-foot (3,760 m) high satellite cone. The fourth and final cone is exposed south of Shasta’s current summit and is called Misery Hill.

Mount McLoughlin and Brown Mountain Volcanoes, Oregon, USA

42.4N 122.3W

July 6th, 2009 Category: Volcanoes

Oregon, USA - June 30th, 2009

Oregon, USA - June 30th, 2009

This orthorectified ASAR (radar) image gives a fine view of the mountainous regions of western Oregon, USA, home to some of the most prominent mountain peaks in the country.

Of particular interest here, in the lower right quadrant, are two volcanoes: Mount McLoughlin (above) and Brown Mountain (below).

Mount McLoughlin is a shield volcano in the Cascade Range of southern Oregon and within the Sky Lakes Wilderness area. It is one of the volcanic peaks in the Cascade Volcanic Arc.

Brown Mountain, on the other hand, is a small basaltic andesite to andesite shield volcano located in Oregon’s Klamath and Jackson counties.

Towards the center of the image is a cluster of white dots, showing the location of the city of Medford, situated in the remains of ancient volcanic flow areas.

Mount Shasta, California, USA

41.3N 122.3W

July 1st, 2009 Category: Volcanoes

California, USA - June 30th, 2009

California, USA - June 30th, 2009

This orthorectified ASAR (radar) image shows Mount Shasta, a 14,179-foot (4,322 m) stratovolcano that is the second-highest peak in the Cascade Range and the fifth highest peak in California. It is a member of the Cascade Volcanic Arc and is located in Siskiyou County.

Mount Shasta is not connected to any nearby mountain; as can be seen here, it rises abruptly from miles of level ground which encircle it, standing nearly 10,000 feet (3,000 m) above the surrounding area.

Mount Shasta has an estimated volume of 108 cubic miles (450 km3), making it the most voluminous stratovolcano in the Cascades.

The mountain consists of four overlapping volcanic cones which have built a complex shape, including the main summit and the prominent satellite cone of 12,330-foot (3,760 m) Shastina, which has a visibly conical form. If Shastina were a separate mountain, it would rank as the third-highest peak of the Cascade Range.

Mount Shasta’s surface is relatively free of deep glacial erosion except, paradoxically, for its south side where Sargents Ridge runs parallel to the U-shaped Avalanche Gulch. This is the largest glacial valley on the volcano, although it does not presently have a glacier in it.

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