The Geology of Mount Shasta
The geology of California is unique. There are two high masses, the Sierra Nevada and lower mountains in the northwest. Between these masses is a lower plain, called the Great Valley. The lower mountains are called the Coast Ranges that extend 1,200 miles from Point Arena, north of San Francisco, to the southern part of the state. This area is subject to tremors and sometimes to severe earthquakes caused by tectonic stress along the San Andreas Fault. The Sierra Nevada range includes Mt. Whitney, Kings Canyon National Park, Sequoia National Park, and Yosemite National Park. The Cascade Range, the northern continuation of the Sierra Nevada, includes Lassen Volcanic National Park.
Mt. Shasta is a 14,179-foot high volcano located in Siskiyou County, California and has a volume of more than eighty cubic miles. The towns of Weed, Mount Shasta and McCloud sit at its base. It is the second highest peak in the Cascade Mountain Range after Mount Whitney. The Cascade Range is a 500-mile long chain of young volcanic mountains that reaches from British Columbia to northern California. There are seven glaciers on Mt. Shasta: Bolam, Hotlu, Konwakiton, Wintun, Mud Creek, Watkins and Whitney. Mt. Shasta does not receive as much snow as other mountains in the area because the Pacific Ocean and Klamath Mountains stop the snow before it reaches Mt. Shasta. The annual snowline is about 10,000 feet.
Mt. Shasta’s History
Mt. Shasta is classified as a stratovolcano, or conical mountain, composed of lava and volcanic ash. Subduction of tectonic plates contributes to the height of these types of volcanoes. The volcano is composed of four overlapping eruptive centers. The oldest center is the Sergeants Ridge cone, located on the lower slopes of Shasta; it was active about 450,000 years ago. Misery Hill, on the northwest flank of the Sergeants Ridge Cone, was active between 15,000 and 20,000 years ago. Shastina, on the west flank of Shasta, was active around 9,200 years ago.
The Hotlum cone is the youngest eruptive center and forms Shasta’s summit. Mount Shasta is a potential hazard because it is not an extinct volcano. Mt. Shasta erupts an average of every 600 to 800 years and the last significant eruption occurred in 1786. The city of Mount Shasta is about ten miles southwest of the volcano, simply called “The Mountain” by the locals. The town of Mount Shasta was originally named Sisson and was changed in 1924.
Native American Groups at Mount Shasta
In the spring of 1792 British navigator George Vancouver entered Puget Sound and started to give English names to the high mountains he saw. However, the first European to “discover” Mt. Shasta was Peter Skene Ogden who named it in 1827 after the local Shastan Indian tribe. E.D. Pearce made the first ascent in 1854.
Native Americans present in the area at this time were the Modocs, who lived primarily on the Modoc Plateau, the Shastans, and the Karuks, who occupied the area along the Klamath River from Seiad Valley to north of Weitchpec in Humboldt County. Also, in the southern areas lived the Wintu, the Achumawi and Astsugewi tribes. The city of Mount Shasta is about ten miles southwest of the volcano, simply called “The Mountain” by the locals. The town of Mount Shasta was originally named Sisson and was changed in 1924.
Surrounding Areas of Mt. Shasta
Surrounding towns include McCloud, Weed and Dunsmuir. McCloud was originally named McLeod’s River, after Alexander Roderick McLeod, who was the Hudson’s Bay Company fur brigade leader. In 1897 the McCloud River Lumber Company renamed the city McCloud. The first Europeans to visit the area were Hudson Bay Company trappers and explorers in 1829. The first mill was built in 1892 but failed because lumber was too difficult to obtain. In 1897 the McCloud River Railroad Company was founded to transport lumber to more populated areas. The mill closed in 2002 and many homes are now being purchased as vacation housing. The old railroad has been reconstructed as a dinner train and provides site seeing excursion.
The town of Weed is about ten miles northwest of Mt. Shasta, fifty miles south of the Oregon border, and is located in Siskiyou County. Weed is named after Abner E. Weed who came to the Mount Shasta area in 1889. Abner Weed built mills however the logging and mill operations have declined sharply in the past few years. Like other rural towns in the area, Weed is turning to tourism for economic support. Currently there is a bowling alley, theater, nine-hole golf course, five parks, a swimming pool and community college.
Dunsmuir was established in the late 1880s with the construction of the railroad line through the Sacramento River canyon. In the 1950s Dunsmuir was the largest town in Siskiyou County until diesel trains were introduced. This also reduced tourism to the area, especially the Shasta Springs Resort and Shasta Retreat, which no longer operate. Dunsmuir was originally called Pusher but in 1886 Alexander Dunsmuir proposed that if the town was renamed after him, he would provide the town a fountain. The town’s economic status was based as a link between the north-south rail line.