The eruption of Mount St. Helens on May 18, 1980, caused the destruction of 27 bridges, over 200 homes and 4.7 billion boards of timber. In addition, 15 miles of railway and 185 miles of highway were damaged or destroyed. Fifty-seven people also lost their lives during the eruption, and another four deaths occurred as an indirect result of the eruption.
In the immediate area, immeasurable damage was caused to the forest area from falling ash, lahars, flooding and mudslides. In the direct blast zone closest to the eruption site, everything within an eight-mile radius was completely obliterated. Aside from the destruction of buildings, cars and forestry, thousands of animals were killed.
When Mount St. Helens erupted, the ash column rose 12 miles high. The ash settled over Washington, Oregon and Idaho, and it even reached Colorado, Minnesota and Oklahoma. The settlement of ash caused the destruction of acres of crops, and thousands of dollars were spent on clean-up efforts. In all, the eruption of Mount St. Helens cost over one billion dollars in damage.
The eruption of Mount St. Helens also had many secondary effects. For example, local tourism was affected by the eruption, and unemployment increased significantly in the area surrounding Mount St. Helens.Learn More
Volcanoes are important for many reasons, including benefiting nearby plants with nutrient-rich ash, providing rare species with habitats that are inaccessible to humans and livestock, and enriching the atmosphere with gases, according to Oregon State University. The Earth's life, water and atmosphere would not exist without volcanoes.Full Answer >
The eruption of Mount Pinatubo in 1991 was the second largest volcanic eruption of the 20th century. The eruption released a huge volume of volcanic ash and sulfur dioxide into the atmosphere. This caused the planet to experience a global cooling in the following year and temperatures to decrease significantly.Full Answer >
The last eruption of Mount Unzen happened in 1995 after a series of at least 10,000 pyroclastic flows that persisted between 1991 and 1994. The worst eruption during this period happened on June 3, 1991 and killed 43 people, including French volcanologists Katia and Maurice Krafft.Full Answer >
A plug dome volcano is a rounded volcano containing very thick lava that congests or “plugs” easily. Plug dome volcanoes come in many different forms. However, they all possess viscous lava that cannot flow readily. These structures form through repeated outpourings of bulbous lava masses around the volcanoes’ vents.Full Answer >