Eruptions of steam, ash, and tephra continued until June 1917, when the volcano resumed its quiet profile, with minor steam clouds occasionally reported. Since 1921, Lassen Peak has remained quiet.

Another claim to fame is that Lassen Peak is the largest plug dome volcano ... are late stage volcanic activity. Since the last eruptions in 1916, Lassen was designated a National Park to keep ...

Its namesake feature, the 10,457-foot Lassen Peak, is one of the world's largest ... State Park owes much of its existence to volcanic eruptions millions of years ago. The park boundaries contain ...