sentence1: The volcanic activity of Mount St. Helens ( 2004-2008 ) has been documented as a continuous eruption with a gradual extrusion of magma at Mount St. Helens volcano .
sentence2: The 2004 -- 08 volcanic activity of Mount St. Helens has been documented as a gradual eruption with a continuous extrusion of magma at the Mount St. Helens volcano .