The Mount St. Helens National Volcanic Monument
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The Mount St. Helens Volcano has shown continuous intermittent volcanic activity since the 1980 eruption, including minor eruptions of steam and ash, and occasional pyroclastic flows. More than a dozen extrusions of lava have built a mound-shaped lava dome in the new crater. Goat Rocks on the northern flank is one of the older lava domes. Experts monitoring the volcano believe there will be adequate warning of the next eruption.
The most recent seismic activity occurred October 2004 and consisted of steam and ash eruptions and lava extrusions resulting in the significant expansion of the lava dome.
Understandably, Mount St. Helens has been studied intensively, and more is known about its eruptive history than that of any other Cascade volcano. It is a relatively "young" volcano, perhaps 40,000 to 50,000 years old. The cone that partly collapsed in 1980 is only 2,200 years old. In the last 515 years, it is known to have produced 4 major explosive eruptions and dozens of lesser eruptions. An eruption in 1480 A.D., was about 5 times larger than the May 18, 1980 eruption,
The May 18, 1980 eruption came after nearly 2 months of thousands of local earthquakes and hundreds of steam eruptions, and the outward growth of the volcano's entire north flank by more than 80 meters. A magnitude 5.1 earthquake struck beneath the volcano, sending the volcano's bulging north flank sliding in the largest landslide in recorded history. This in turn triggered a lethal lateral blast of hot gas, steam, and rock debris lasting only a few minutes, but which swept across the landscape as fast as 1,100 kilometers per hour. The next 9-hours of continuous eruption, were followed by 3 days of intermittent eruptions, then 5 smaller explosive eruptions over a period of 5 months.
Altogether, about 4 billion cubic yards of new and old lava material and about 170 million cubic yards of glacial snow and ice were deposited over the landscape, as a result of the May 18 eruption. Some debris and mud-flows, were so voluminous that they reached and blocked the shipping channel of the Columbia River about 70 river miles from the volcano. The eruption itself blew volcanic ash more than 15 miles into the air, within minutes. Winds carried about 490 tons of ash generally eastward across the United States and, in trace amounts, around the world. The ash fell in troublesome amounts as far east as western Montana. About 60 persons were dead or missing.
Best selection of books on the Northwest.
Eruption: The Untold Story of Mount St. Helens by Steve Olson. Learn the history and science of one of the largest eruptions and the effects of the aftermath through personal stories and accounts of those caught in the disaster. Illustrations and maps enable a greater understanding of this tragic event. Order now...
Day Hiking Mount St. Helens by Craig Romano and Aaron Theison. This Mountaineers Book features every trail within and around the monument. Hikes are arranged by regions with trail descriptions, directions to trailheads and difficulty ratings along with other useful information and photographs. Order now...
Mount St. Helens 35th Anniversary Edition: The Eruption and Recovery of a Volcano by Rob Carson. Along with remarkable before-and-after images, this 35th-anniversary retrospective captures the human drama leading up to the eruption and two decades of subsequent scientific research of the amazing post-blast ecological recovery. Order now...
A Falcon Guide to Mount St. Helens: A Guide to Exploring the Great Outdoors by Fred Barstad. This book is a comprehensive guide to this world-renowned attraction, with a close-up look at the destruction and recovery of the area. The guide includes detailed information on the natural and cultural history of the area, recreational opportunities, and historical, geological, and natural exhibits. Order now...
In the Blast Zone: Catastrophe and Renewal on Mount St. Helens by Charles Goodrich, Kathleen Dean Moore and Frederick Swanson. This book presents a cross-pollination of literary and scientific perspectives on the mountain's history of cataclysm and renewal. Discover the gifts of beauty, scientific illumination and of hope. Order now...
Portrait of Mount St. Helens: A Changing Landscape by Chuck Williams (Author) and Stuart Warren (Contributor). View the grandeur and the intimate detail of this beloved mountain as seen by 19th-century painters and pioneers as well as contemporary photographers. Order now...
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