Mount Shasta's magma is composed of basalts and basaltic andesite. These two types of magma are very runny, forming large shield cones and steep, loose tephra cones. The basaltic andesites at Mount Shasta are unusually rich in magnesium.
Mount Shasta is located in northern California and is the second largest volcano in the Cascade Range. Mount Shasta's landscape includes four overlapping cones and seven glaciers. Rising nearly 10,000 feet in the air, it is remarkable for the large avalanche that removed its entire northern side approximately 300,000 years ago. This was one of the largest avalanches known on Earth. The last confirmed eruption of Mount Shasta was in 1786.