Lassen Peak is not considered an active volcano in the traditional sense. It last erupted in 1915, and while it's possible for it to erupt again in the future, it's not currently showing any signs of imminent activity.

However, Lassen Peak is still considered volcanically active. This means it's part of a larger volcanic system, and its geothermal activity continues to be present. This is evident through features like hot springs, fumaroles (steam vents), and mud pots.

So, while Lassen Peak might not erupt anytime soon, it remains a significant part of a vibrant volcanic area and should be treated with respect.