It reached its maximum size at about midnight in the Cowlitz River about 50 miles downstream from the volcano. The cataclysmic eruption of Mount St.
Erupted volume** (million cubic yards)
| m | Minor |
|---|---|
| ** | Volumes based on lava flows plus uncompacted airfall ash and pyroclastic flows |
How much volume did Mt St Helens lose?
On May 18, 1980, the volcano lost an estimated 3.4 billion cubic yards (0.63 cubic mile) of its cone (about 1,300 feet or 396 meters in height), leaving behind a horseshoe-shaped crater (open to the north), with the highest part of the crater rim on the southwestern side at 8,365 feet (2,550 meters) elevation.
How much material did Mt St Helens erupt?
During the 9 hours of vigorous eruptive activity on May 18, 1980, about 540 million tons of ash from Mount St. Helens fell over an area of more than 22,000 square miles (57,000 square kilometers).
How big was the Mt St Helens eruption?
Notable Statistic: The May 18, 1980 blast devastated 596 square kilometers (229 square miles) and destroyed timber valued at several million dollars. This was the deadliest and most economically destructive volcanic event in the history of the United States.
What rock does Mt St Helens erupt?
The range of rock types erupted by the volcano changed about 2,500 yr ago, and since then, Mount St. Helens repeatedly has produced lava flows of andesite, and on at least two occasions, basalt.
How much bigger would the Yellowstone than Mt St Helens?
The three caldera-forming eruptions at Yellowstone (2.1 million years ago, 1.3 million years ago, and 640,000 years ago), were respectively about 2,500, 700, and 1,000 times larger than the 1980 eruption of Mt. St. Helens in the state of Washington.
How far did debris go from Mt St Helens?
The lateral blast devastated an area nearly 30 km (19 mi) from west to east and more than 20 km (12.5 mi) northward from the former summit. In an inner zone extending nearly 10 km (6 mi) from the summit, virtually no trees remained of what was once dense forest.
How much ash came from Mt St Helens?
about 540 million tons
How much ash was there from the May 18, 1980 eruption of Mount St. Helens? During the 9 hours of vigorous eruptive activity on May 18, 1980, about 540 million tons of ash from Mount St. Helens fell over an area of more than 22,000 square miles (57,000 square kilometers).
How deep was the ash from Mt St Helens?
2 inches
Ash and pumice piled 6 miles (9.7 km) northeast of the volcano to a thickness of 3 feet (0.9 m); 50 miles (80 km) away, the ash was 2 inches (5 cm) deep. Large pyroclastic flows and mudflows subsequently rushed down St.
Did they know Mt St Helens was going to erupt?
In 1980, Mt St. Helens’ continued seismicity warned scientists at monitoring stations that the volcano might erupt, but the danger zone around the mountain turned out to be much too small.
How big was Mt St Helens eruption compared to atomic bombs?
In total, Mount St. Helens released 24 megatons of thermal energy, seven of which were a direct result of the blast. This is equivalent to 1,600 times the size of the atomic bomb dropped on Hiroshima.
How far was the Mt St Helens eruption felt?
(AP) — Mount St. Helens erupted yesterday with a violence blast that blew 600 feet off its summit. the eruption was felt 200 miles away, belching ash and hot gas that blotted out the sun for more than 100 miles. At least nine people were killed.
What did Mount Saint Helens eruption look like?
The lateral blast scorched and flattened about 230 square miles of dense forest, blanketing the area in hot debris. Within 15 minutes, a plume of volcanic ash rose over 80,000 feet. Over the next few days, winds blew the 520 million tons of ash east across the U.S. causing complete darkness 250 miles away in Spokane.
How loud was Mt St Helens?
163 decibels
On 18th May 1980, Mount St Helens erupted in Skamania County, Washington. The force was enough to blow down trees 16 miles away and it was seen on the Space Shuttle from outer space. The sound measured 163 decibels and the force blew windows out up to 200 miles away in Seattle!
What type of flow was Mt St Helens?
During the May 18, 1980 eruption, at least 17 separate pyroclastic flows descended the flanks of Mount St. Helens. Pyroclastic flows typically move at speeds of over 60 miles per hour (100 kilometers/hour) and reach temperatures of over 800 Degrees Fahrenheit (400 degrees Celsius).
Did lava flow from Mt St Helens?
Lava flows from Mount St. Helens typically affect areas within 6 mi (10 km) of the vent. However, two basalt flows erupted about 1,700 years ago extended about 10 mi (16 km) from the summit; one of them contains the Ape Cave lava tube. Sources/Usage: Public Domain.
What is the biggest supervolcano on Earth?
Taupo erupted 22,600 years ago and is the most recent supereruption on Earth (with a volume of about 1,130 cubic kilometers). Additional volcanoes capable of producing supereruptions include the large caldera volcanoes of Japan, Indonesia, and South America.
What are the 3 super volcanoes in the US?
Three of the seven supervolcanoes are located in the continental US: Yellowstone, the Long Valley Caldera, and the Valles Caldera. The most well known supervolcano is in Yellowstone National Park, Wyoming (shown above).
How big would the blast be from Yellowstone?
Based on past research and the general location of the volcano itself, the blast radius of Yellowstone’s calderas is quite large. When it comes to lava and magma flows spewing forth from this volcanic eruption, Yellowstone National Park would likely need to evacuate everyone within a 40 to 50 mile radius.
How long does ash stay in the air?
So, how does the ash get spread so far from the site of the eruption? The simplistic view of ash behavior in the atmosphere would suggest that very small (> 30 μm) ash should stay aloft for days to weeks – the settling rate is between 10–1 to 10–3 m/s if you apply Stokes Law to the settling of the ash.
How far away was the furthest victim from Mt St Helens?
During the eruption, 57 people were killed. 7: How far away was the furthest victim? The farthest victim was about 13 miles away.