- Status: Mount Shasta is monitored by the Long Valley and Cascades Volcano Observatory. It is at a background level of activity.
- Volcanic History Overview: The most voluminous of the Cascade volcanoes, northern California's Mount Shasta is a massive compound stratovolcano composed of at least four main edifices constructed over a period of at least 590,000 years. An ancestral Shasta volcano was destroyed by Earth's largest known Quaternary subaerial debris avalanche, which filled the Shasta River valley NW of the volcano. The Hotlum cone, forming the present summit, and the Shastina lava dome complex were constructed during the early Holocene, as was the SW flank Black Butte lava dome. Eruptions from these vents have produced pyroclastic flows and mudflows that affected areas as far as 20 km from the summit. Eruptions from Hotlum cone continued throughout the Holocene. Shasta's only historical eruption was observed from the ship of the explorer La Perouse off the California coast in 1786.
- Location: Western US, CA
Elevation: 4317 m
Recent Eruption: Shasta's only historical eruption was observed from the ship of the explorer La Perouse off the California coast in 1786.
- Hazard Assessments: Potential Hazards from Future Eruptions in the Vicinity of Mount Shasta Volcano, Northern California, Miller, 1980, USGS Bulletin 1503.
- Link to monitoring data:
Volcanic Alert Level: NORMAL Aviation Color Code: GREEN