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Intense earthquake activity persisted at the volcano during and between visible eruptive activity.

As early as March 31, seismographs also began recording occasional spasms of volcanic tremor, a type of continuous, rhythmic ground shaking different from the discrete sharp jolts characteristic of earthquakes.

The combination of sustained strong earthquake activity and harmonic tremor at Mount St.Helens, as painted by Canadian artist Paul Kane following a visit to the volcano in 1847 (Photograph courtesy of the Royal Ontario Museum). The two braves, Wyeast and Klickitat fought over her, burying villages and forests in the process ( hurling rocks as they erupted? Because Loowit was beautiful, her mountain (Mount St. Helens began to grow before the last major glaciation of the Ice Age had ended about 10,000 years ago.Helens) was a beautiful, symmetrical cone of dazzling white. The local Indians and early settlers in the then sparsely populated region witnessed the occasional violent outbursts of Mount St. The volcano was particularly restless in the mid-19th century, when it was intermittently active for at least a 26-year span from 1831 to 1857. Helens also was active sporadically during the three decades before 1831, including a major explosive eruption in 1800. Hopson, and their associates, who began their studies in the late 1950's, has particularly advanced knowledge of Mount St. Their systematic studies of the volcanic deposits, laboratory investigations of rock and ash samples, and radiocarbon (carbon-l4) dating of plant remains buried in or beneath the ash layers and other volcanic products enabled them to reconstruct a remarkably complete record of the prehistoric eruptive behavior of Mount St. The oldest ash deposits were erupted at least 40,000 years ago onto an eroded surface of still older volcanic and sedimentary rocks.Vancouver also named three other volcanoes in the Cascades--Mounts Baker, Hood, and Rainier--for British naval officers. According to one Indian legend, the mountain was once a beautiful maiden, "Loowit".Indians on the Cowlitz River watching an eruption of Mount St. Helens blew its top is was a beautifully symmetric rounded snow-capped mountain that stood between two powerfully jagged peaks Mt. When two sons of the Great Spirit "Sahale" fell in love with her, she could not choose between them. He smote the three lovers and erected a mighty mountain peak where each fell.Helens "Louwala-Clough," or "smoking mountain." The modern name, Mount St.Helens, was given to the volcanic peak in 1792 by Captain George Vancouver of the British Royal Navy, a seafarer and explorer.In contrast, the gently sloping shield volcanoes, such as those in Hawaii, typically erupt nonexplosively, producing fluid lavas that can flow great distances from the active vents.Although Hawaiian-type eruptions may destroy property, they rarely cause death or injury.The crown of the ash column rose to about 6,000 feet above the volcano.The initial explosions formed a 250-foot-wide crater within the larger, preexisting snow- and ice-filled summit crater, and new fractures broke across the summit area. Helens, from a measurement site about 2 miles to the northeast (Photograph by Peter Lipman).


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