 With the exception of the 1915 eruption of remote Lassen Peak in Northern California, the range was quiet for more than a century.Then, on May 18, 1980, the dramatic eruption of Mount St. Helens shattered the quiet and brought the world's attention to the range.Geologists were also concerned that the St. Helens eruption was a sign that long-dormant Cascade volcanoes might become active once more, as in the period from 1800 to 1857 when a total of eight erupted.