Mammoth Mountain is technically not an active volcano because it hasn't erupted in the last 10,000 years. ... Mammoth Mountain is one of many volcanoes in the Mono-Inyo Craters volcanic chain that stretches from Mono Lake to just south of Mammoth Mountain.

Is there a volcano in Mammoth?

Mammoth Mountain is a 3,369-m (11,053-ft) high volcano lies west of the structural rim of the caldera and is considered to represent a magmatic system distinct from Long Valley Caldera and the Mono-Inyo Craters. The latest magmatic eruptions at Mammoth Mountain took place about 50,000 years ago. ...

What Caused Mammoth Mountain to erupt?

Phreatic eruptions, distinct from those at South Inyo Craters, took place about 700 years ago from vents on the north side of Mammoth Mountain. Recent volcanic unrest, including seismicity, gas emission, and tree kill, is thought to be related to a dike intrusion beneath Mammoth Mountain in 1989.