Crater Lake Region
Upper Klamath Lake &
Klamath Falls Region
The Klamath Basin,
Tulelake & Lava Beds
Butte Valley Region
Mount Shasta Region
The Waterfalls Region:
McCloud & Burney
Hat Creek Rim
Mount Lassen Region
Lake Almanor Region
Trip Planner
Volcanic Spectacles
History
Recreation
Events Calendar
Travel with Kids
Lodging & Services
RV & Camping
Fishing & Hunting
Scenic WondersThe Volcanic Legacy Scenic Byway traverses the southern section of the great Cascade range, a chain of active volcanoes that stretch from the Canadian border to northern California.
Of the 13 potentially active volcanoes in the Cascade Range of the Pacific Northwest, 11 have erupted in the past 4,000 years and 7 in just the past 200 years. Cascades volcanoes tend to erupt explosively, and on average two eruptions occur per century--the most recent were at Mount St. Helens, Washington (1980-86), and Lassen Peak, California (1914-17).
The major volcanoes you will explore along the Byway are Crater Lake,
Medicine Lake, Mount Shasta and Mount Lassen. Crater
Lake, or Mount Mazama, is the least active of these peaks...it has not
been active for over 4000 years. The 6 mile wide caldera, which Crater Lake
now fills, formed when a massive ash eruption 6,950 years ago emptied the
magma chamber underneath Mount Mazama, causing it to collapse. The four
thousand foot deep hole has filled with rain and snowmelt to a depth of about
1,900 feet. Seepage and evaporation now balance the incoming precipitation,
and the level of the lake remains nearly constant.
While not the tallest, the Medicine Lake volcano is actually the largest
volcano along the Byway. In fact, with a volume of more than 130 cubic
miles, it is the largest volcano in the entire Cascade range. Medicine
Lake Volcano, a broad shield capped by a 4- by 7-mile caldera, has erupted
at least 8 times in the past 4,000 years, most recently about 900 years
ago. This photo from the USGS shows the Medicine Lake caldera with Mount
Shasta in the distance.
Although a small peak, Black Butte is a unique volcano (and not a small
part of its nearby neighbor Mount Shasta). In the middle of the valley
to the west of Mount Shasta, and often mistaken for it by visitors when
the bigger mountain is obscured by clouds, the tiny Black Butte volcano
is made of four overlapping dacite lava domes that erupted about 9,500 years
ago. A Forest Service fire lookout cabin once covered the top of Black Butte.
Today, this peak provides one of the finest hikes of the entire Byway region.
At 4317 meters above seal level, Mount Shasta is the tallest volcano
on the Byway...one of the largest composite cones (or stratovolcanos) in
the world, so-called because the volcano actually consists of the remains
of at least four different cones, two of which were destroyed by erosion or
explosion. Mount Shasta has been the most active volcano in California during
the past 4,000 years, and is second in the entire Cascade Range only to Mount
St. Helens. During that time, Shasta has erupted on average about once every
300 years, producing many pyroclastic flows. It probably last erupted in
1786. Shastina, the northernmost peak of Mount Shasta, is a large subsidiary
cone that rises to 3,758 meters on the west flank of the compound volcano.
Lassen Volcanic Field, including Lassen Peak, is the southernmost volcanic
center in the Cascades. The most recent volcanic eruptions in California
occurred at Lassen Peak from 1914 to 1917. An explosive eruption on May
22, 1915, produced a large pyroclastic flow, lahars, and ash that fell as
far away as Elko, Nevada, 300 miles to the east.You will pass many more small volcanoes as you drive the Byway. The Cascades are actually made up mostly of hundreds (even thousands) of small shield volcanoes that lie between the large stratovolcanoes like Mount Shasta and Crater Lake (the former Mount Mazama). Deer Mountain, for example, on the road between Weed and Dorris in northern California, is a fairly small shield volcano separate from both Mount Shasta and the Medicine Lake volcano.
Please follow the links below to discover information on the volcanic features found along the Volcanic Legacy Scenic Byway.
- Visit the Cascades Volcano Observatory on the Web. This extensive web site from the U. S. Department of the Interior - U. S. Geological Survey, has a wealth of information about the volcanoes of the Byway and the entire Cascade range.
- Does Pumice float? ... What is the tallest volcano in the Cascade Range? ... Test how well you know your volcanoes and volcanic terminology ... Here are the 59 "Most Frequently Asked Questions" (with answers) covering general information, Mount St. Helens and the Cascade Range Volcanoes, Alaskan and Hawaiian Volcanoes, and volcanic features and processes. ... Enjoy!
- How did the volcanoes get their names? Visit Volcano Names and History for the answers.
- Learn lots about Mount Mazama at the Geology of Crater Lake pages.
- Lava Beds National Monument is located on the north flank of the Medicine Lake volcano. Find information on this area of the Byway at the Lava Beds National Monument Geology pages.
- Read an Introduction to the Geology of the Mount Shasta Region from Dr. William Hirt at College of the Siskiyous in nearby Weed, Califonria.
- Lots more about the geology of northern California from the geology program at the College of the Siskiyous, including Local Geology Links and "Is this a dangerous volcano?" describing Mount Shasta's eruptive history and its likely future activity.
- Discover Mount Lassen volcanic information at the Nature and Science section of the Lassen Volcanic National Park web site.
- Learning more about volcanoes is easy with the illustrated glossary at the USGS web site. Just click on a word (like pyroclastic flow, lava dome, shield volcano or cinder cone) to see its picture and read the definition.
- Discover the Subway Caves
just south of Burney-- on Hwy 89, just a 1/4 of a mile North on Hwy
44.
VolcanicLegacyByway.org