Mount St. Helens Research Paper
Introduction
For five hours, multiple avalanches of hot ash, pumice, and gases poured out of the crater. During explosive eruptions, fiery, pyroclastic flows travel down slope from a volcano. The Mount St. Helens pyroclastic flow spread as far as five miles north of the crater. The hot lava flows and suffocating ash falls destroying plant and animal life. The eruptions are over, but consequences go on. What happens to the surrounding environment after such an eruption? The Earth repairs itself from the destructive effects of the lava, gases and ash spewed by the eruption of Mount St. Helens. It is the short-term hazards posed by volcanoes that are balanced by benefits of volcanism and related processes over geologic time. A factor …show more content…
Mount St. Helens, other active Cascade volcanoes, and those of Alaska form the North American segment of the Pacific "Ring of Fire," a notorious zone that produces frequent, often destructive, earthquake and volcanic activity.
Work done by geologist in the 1950s used methodical studies of the volcanic deposits, laboratory investigations of rock and ash samples, they also used radiocarbon (carbon-l4) dating of plant remains buried in and beneath the ash layers and other volcanic debris has allowed them to reconstruct a complete record of the prehistoric eruptive behavior of Mount St. Helens. Historical Stages Volcanologists have named four stages of volcanic activity, Ape Canyon, Cougar, Swift Creek, and Spirit Lake. These stages are separated by dormant intervals. Little is known about the Ape Canyon stage (300-35 thousand years ago) (ka). During this stage, lava domes in two distinct periods, one from 300 to 250 thousand years ago (ka) and a second from 125-35 ka. Geologists have found layers of ash and rocks that were changed hydrothermally, …show more content…
It appeared to oringinate directly under Mount St. Helens. As usual aftershocks followed the next day. What was unusal was the aftershocks continued into Saturday and Sunday with more frequent aftershocks and the epicenter seems to be rising toward the surface. “By Monday March 24, the number of earthquakes had jumped to more than one per minute, some as strong as 4.0 on the Richter scale”. (Carson, 2000, p. 29) As experts gathered in the region with local and state athourites they decieded to close part of the mountian off above the timberline as a precaution. A local radio traffic reporter looking for a new story angle about the mountian, flew near the summit and saw steam and black ash discharging from a hole in the snow. This was hidden from a ground veiw because of overcast skies. When the plume subsided and the skies cleared aerial observers saw a new crater 200 feet in diameter and 150 feet deep opend on the top of the mountianalong with cracks up to three miles long running east to west near the summit, indicating that the north side of the peak was starting to droop. Later on March 30 Mount St. helens had 93 small eruptions of steam and ash that spewed from the summit. In April seimometers recorded tremors that were rhytmic and continous which indicate magma moving beneath the Earth’s surface. Geolgist’s knew that Mount St. Helens would explode but when was everyones question.
For five hours, multiple avalanches of hot ash, pumice, and gases poured out of the crater. During explosive eruptions, fiery, pyroclastic flows travel down slope from a volcano. The Mount St. Helens pyroclastic flow spread as far as five miles north of the crater. The hot lava flows and suffocating ash falls destroying plant and animal life. The eruptions are over, but consequences go on. What happens to the surrounding environment after such an eruption? The Earth repairs itself from the destructive effects of the lava, gases and ash spewed by the eruption of Mount St. Helens. It is the short-term hazards posed by volcanoes that are balanced by benefits of volcanism and related processes over geologic time. A factor …show more content…
Mount St. Helens, other active Cascade volcanoes, and those of Alaska form the North American segment of the Pacific "Ring of Fire," a notorious zone that produces frequent, often destructive, earthquake and volcanic activity.
Work done by geologist in the 1950s used methodical studies of the volcanic deposits, laboratory investigations of rock and ash samples, they also used radiocarbon (carbon-l4) dating of plant remains buried in and beneath the ash layers and other volcanic debris has allowed them to reconstruct a complete record of the prehistoric eruptive behavior of Mount St. Helens. Historical Stages Volcanologists have named four stages of volcanic activity, Ape Canyon, Cougar, Swift Creek, and Spirit Lake. These stages are separated by dormant intervals. Little is known about the Ape Canyon stage (300-35 thousand years ago) (ka). During this stage, lava domes in two distinct periods, one from 300 to 250 thousand years ago (ka) and a second from 125-35 ka. Geologists have found layers of ash and rocks that were changed hydrothermally, …show more content…
It appeared to oringinate directly under Mount St. Helens. As usual aftershocks followed the next day. What was unusal was the aftershocks continued into Saturday and Sunday with more frequent aftershocks and the epicenter seems to be rising toward the surface. “By Monday March 24, the number of earthquakes had jumped to more than one per minute, some as strong as 4.0 on the Richter scale”. (Carson, 2000, p. 29) As experts gathered in the region with local and state athourites they decieded to close part of the mountian off above the timberline as a precaution. A local radio traffic reporter looking for a new story angle about the mountian, flew near the summit and saw steam and black ash discharging from a hole in the snow. This was hidden from a ground veiw because of overcast skies. When the plume subsided and the skies cleared aerial observers saw a new crater 200 feet in diameter and 150 feet deep opend on the top of the mountianalong with cracks up to three miles long running east to west near the summit, indicating that the north side of the peak was starting to droop. Later on March 30 Mount St. helens had 93 small eruptions of steam and ash that spewed from the summit. In April seimometers recorded tremors that were rhytmic and continous which indicate magma moving beneath the Earth’s surface. Geolgist’s knew that Mount St. Helens would explode but when was everyones question.