Mount Shasta is a stratovolcano located in the United States, standing at an elevation of 4,317 meters within a subduction zone and continental crust tectonic setting. According to the Smithsonian Global Volcanism Program's official records, the volcano has a confirmed total of 22 eruptions spanning thousands of years, with the earliest recorded eruption starting around 8050 BCE and the latest recorded eruption beginning around 1250 CE.
As an active volcanic system with a long history of activity, Shasta's historical record provides insight into recurring geological events over millennia. The official record documents distinct eruptive periods identified through various scientific evidence methods, including tephrochronology correlation and uncalibrated radiocarbon dating.
Eruption History and Overview
The historical record for Shasta comprises 22 confirmed eruptions cataloged across multiple centuries, beginning in the 9th millennium BCE and extending into the 13th century CE. Because the available dataset includes representative records alongside aggregate totals, scientists track these events using established geological dating techniques.
The largest recorded eruption in the available Smithsonian data reached a Volcanic Explosivity Index (VEI) of 4.0. This event is documented with an uncalibrated radiocarbon dating method and occurred around 7650 BCE, with an estimated year uncertainty of 100 years, involving activity across the summit, south flank (Red Banks), and Shastina.
Chronology of Recorded Activity
The confirmed eruptions span a wide temporal distribution from antiquity through the medieval period. The earliest recorded eruption began around 8050 BCE, determined through tephrochronology correlation. Subsequent activity recurred across various millennia and centuries, including significant dates such as 7650 BCE (VEI 4.0), 7250 BCE, and 2550 BCE, continuing up to the latest recorded eruption year of 1250 CE.
Frequently asked questions
How many confirmed eruptions does Shasta have?
According to the Smithsonian Global Volcanism Program, Shasta has 22 confirmed eruptions.
When was the earliest recorded eruption at Shasta?
The earliest recorded eruption in the official record began around 8050 BCE.
When was the latest recorded eruption at Shasta?
The latest recorded eruption in the official record began around 1250 CE.
What is the largest recorded VEI for Shasta?
The largest recorded Volcanic Explosivity Index (VEI) for Shasta is 4.0.
Sources and further context
Official datasets support the event-specific facts.