The landslide travelled at 112-240 km/h, with a volume of 2.8 cubic km. The average depth of the landslide was 46 meters but it reached 182 meters deep. The volcano sent a mix of lava and pulverized rock toward Spirit Lake.
How fast was the blast from Mt St Helens?
Once the side of the mountain was removed, the volcanic gases exploded out of the side of the volcano producing a lateral blast. This blast, traveling at speeds of up to 1,072 km/hr (670 mi/hr), quickly overtook the landslide and extended to up to 30.4 km (19 mi) from the volcano.
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 far did Mt St Helens pyroclastic flow travel?
Pyroclastic flows from the May 18, 1980, eruption ran out no farther than 8 km (5 mi) from the vent. During the past 4,000 years, numerous pyroclastic flows are known to have traveled at least as far as 10 to 15 km (6 to 9 mi) and one older flow reached 20 km (12 mi) from source.
How fast does a volcanic explosion travel?
With rock fragments ranging in size from ash to boulders that travel across the ground at speeds typically greater than 80 km per hour (50 mph), pyroclastic flowsknock down, shatter, bury or carry away nearly all objects and structures in their path.
How big was the blast zone of Mt St Helens?
about 230 square miles
At Mount St. Helens, the “uncorking” unleashed a tremendous, northward-directed lateral blast of rock, ash, and hot gases that devastated an area of about 230 square miles in a fan-shaped sector north of the volcano.
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.
How far away was Mt St Helens heard?
The eruption that morning mowed down some 200 square miles of forest and collapsed the mountain’s elevation from 9,677 feet to 8,365 feet. The explosion was heard more than 150 miles away.
How far did the ash from Mt St Helens go?
The total volume of the ash before its compaction by rainfall was about 0.3 cubic mile (1.3 cubic kilometers), equivalent to an area the size of a football field piled about 150 miles (240 kilometers)…
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 long does ash stay in the air?
Some of the ash drifted around the globe within about 2 weeks. After circling many more times, most of the ash settled to the Earth’s surface, but some of the smallest fragments and aerosols are likely to remain suspended in the upper atmosphere for years.
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 far can ash from a volcano travel?
Bottom Line: Volcanic Ash Can Travel 10,000s of Miles!
How far volcanic ash travels depend on a variety of factors, but ash from powerful volcanos have hovered in the atmosphere for years, traveling 10,000s of miles.
Can a human outrun lava flow?
Can you outrun (or walk) lava flows? The average adult human can walk at around 5 km/hr (3.1 miles/hr) and jog at around 11 km/hr (7 miles/hr). In short bursts humans can run at 32 km/hr (20 miles/hr). So people could easily walk, jog or run away from almost all lava flows….
Can you outrun flowing lava?
Depending on its composition, lava ranges from 10,000 to 100 million times as viscous as water. This means even the runniest molten rock has the viscosity of room temperature honey. Unless you’re on a very steep slope, you can generally outrun it.
Can you outrun lava flows?
Lava flows typically move slowly enough to outrun them, but they will destroy everything in their path.
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 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 deep is the crater floor below the summit of Mount St. Helens?
Helens’ height by about 1,300 feet (400 m) and left a crater 1 mile (1.6 km) to 2 miles (3.2 km) wide and 0.4 miles (600 m) deep, with its north end open in a huge breach. The eruption killed 57 people, nearly 7,000 big-game animals (deer, elk, and bear), and an estimated 12 million fish from a hatchery.
How long did it take for life to return to Mt. St. Helens?
When Mount St. Helens erupted, hundreds of square miles of forest were destroyed. Forty years later, life has returned.
How big was the bulge on the northern face of Mount St. Helens?
450 feet
Helens underwent a catastrophic and deadly eruption, triggering the largest landslide ever recorded. Earlier in the year, thousands of small earthquakes, venting steam, and a growing bulge protruding 450 feet (140 m) indicated that magma was rising in the volcano.