A “bulge” developed on the north side of Mount St. Helens as magma pushed up within the peak. Angle and slope-distance measurements to the bulge indicated it was growing at a rate of up to five feet (1.5 meters) per day.
How fast was the lateral blast from Mt St Helens?
670 mph
St. Helens’ lateral blast devastated an area of 230 square miles (600 square km), and blew down wide swaths of forest, splintering and snapping some tree like matchsticks. The blast travelled at speeds up to 670 mph (1080 k/hr), and left a thin deposit of warm rock fragments and ash.
How fast was the lava flow at Mt St Helens?
50 to 80 miles per hour
| Volcano | |
|---|---|
| Area covered | 6 square miles; reached as far as 5 miles north of crater |
| Volume & depth* | 0.029 cubic miles (155 million cubic yards); multiple flows 3 to 30 feet thick; cumulative depth of deposits reached 120 feet in places |
| Velocity | Estimated at 50 to 80 miles per hour |
| Temperature | At least 1,300¡ F (700¡ C) |
Did they know Mt St Helens was going to explode?
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 long was Mt St Helens asleep?
123-year
A magnitude 4.2 (Richter Scale) earthquake on March 20, 1980, at 3:47 p.m. Pacific Standard Time (PST), preceded by several much smaller earthquakes beginning as early as March 16, was the first substantial indication of Mount St. Helens’ awakening from its 123-year sleep.
How far away were trees blown down Mt St Helens?
Within 10 kilometers (6.2 miles) north, it didn’t matter whether the trees were on the near or far sides; the blast cloud “followed topography, eroding timber as it slowed down into each valley and up over each succeeding traverse ridge.” Where it passed, the trees were simply gone, leaving behind nothing but shattered
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.
What is the fastest lava flow ever recorded?
On January 10,1977, a lava lake at Nyiragongo drained in less than one hour. The lava erupted from fissures on the flank of the volcano and moved at speeds up to 40 miles per hour (60 km/hr).
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.
What president was killed by Mt. St. Helens?
Harry R. Truman
| Harry R. Truman | |
|---|---|
| Truman near his lodge in 1980, a few months before his death | |
| Born | October 30, 1896 Ivydale, West Virginia, U.S. |
| Died | May 18, 1980 (aged 83) Mount St. Helens, Washington, U.S. |
| Occupation | Bootlegger, prospector, caretaker of the Mount St. Helens Lodge |
Did any life survive the eruption of Mount St. Helens?
FAQ 3: Did any life survive the 1980 eruption? Although the ash-covered ground appeared lifeless after the May 18, 1980, eruption, scientists found that not everything had died. In fact, much to scientists’ surprise, thousands of plants, animals, and fungi survived in much of the disturbed area.
How loud was Mt St Helens?
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!
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.
What animal survived Mt St Helens?
Gophers were able to survive underground after the 1980 Mount St. Helens eruption and helped plants thrive again.
Will Mt St Helens rebuild itself?
St. Helens will continue to rebuild itself. The eruption that started a decade ago was the second of two dome-building phases.
How tall did Mt St Helens used to be?
9,677 feet
How high was it after? Before May 18, 1980, Mount St. Helens’ summit altitude of 9,677 feet (2,950 meters) made it only the fifth highest peak in Washington State.
What was found in Spirit Lake three years after the eruption?
About 350,000 acre-feet of pyrolized trees were deposited into Spirit Lake and these shattered trees formed a floating log raft on the lake surface that is present to this day, more than three decades after the event.
How far did the 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.
How big was the St Helens tsunami?
The megatsunami in Spirit Lake, Washington, USA that was caused by the 1980 eruption of Mount St. Helens reached 260 metres (853 ft), while the tallest megatsunami ever recorded (Lituya Bay in 1958) reached a run-up height of 520 metres (1,720 ft).
How many nukes are equal to a volcanic eruption?
James Garvin, the chief scientist at NASA’s Goddard Space Flight Center, told NPR that they came up “with a number that’s around 10 megatons of TNT equivalent.” With an estimated explosive yield of 10 megatons of TNT equivalent, the volcano blast was equivalent to the force of roughly 667 “Little Boy” atomic bombs.
What if you nuke a volcano?
The explosion of the bomb mixed with the build-up of pressure inside a volcano could amplify the eruption. The force would release even more ash and lava, spreading it even further than it would’ve gone with the volcano’s own power.