How Was Mount Saint Helens Formed

Geology and History Summary for Mount St. Helens

Mount St. Helens’ digital elevation map, including annotations of pre-1980 topography and deposits from 1980 to 2008, is shown below. The location of magma generation, accumulation, and storage under Mount St. Helens is shown in the diagram below (locations are inferred from scientific data). Located around 53 kilometers (33 miles) due west of Mount Adams and approximately 80 kilometers (50 kilometers) northeast of the Vancouver, Washington—Portland, Oregon metropolitan region, the volcano is active.

Helens and other volcanoes in the Cascades arc are experiencing volcanic activity as a result of the subduction of the Juan de Fuca plate off the western coast of North America.

Helens has generated both powerful explosive eruptions of volcanic tephra and relatively calm lava outpourings throughout the course of its long and complicated 275,000-year history.

After a few thousand years of growth, the volcano reached its pre-1980 elevation of 2,950 meters (9,677 feet), making it the sixth tallest mountain in Washington state at the time.

Massive lava flows buried huge portions of a center cluster of dacite domes and surrounding fans, which signaled the commencement of the cone-building process in full swing.

Helens has developed from a relatively basic to a more complicated state as the volcano has grown, based on a careful chemical examination of the eruptive products from each stage of volcanism.

Mount St. Helens

Mount St. Helens is a volcano in the U.S. state of Washington that erupted in 1980. It is the most active volcano in the Cascade Range, a mountain range that stretches from British Columbia through Washington and Oregon to northern California, and it is the most active volcano in the United States. Since the beginning of recorded history, Mount St. Helens has alternated between periods of cataclysmic eruptions and lengthy stretches of relative calm. However, on May 18, 1980, after a few of months of seismic activity and mild volcanic flare-ups, Mount St.

Thousands of acres of land were devastated and whole animal and plant groups were wiped off by the 1980 volcanic eruption, which claimed the lives of more than 50 people.

It darkened the skies for hundreds of kilometers around, emitted a massive ash cloud that circled the globe, and radically altered the terrain of the mountain and its surrounding areas, among other things.

Ring of Fire

Located in the Pacific Northwest, Mt. St. Helens and the surrounding Cascade Range are part of the Pacific Ring of Fire, an area of intense volcanic and seismic activity stretching from the west coast of South America to the Aleutian Islands, as well as northward through Central and North America to Alaska and the Aleutian Islands. After crossing the Pacific Ocean to the east coast of Asia (including eastern Siberia and Japan), the Ring of Fire extends to include islands in Oceania and the Pacific Ocean, stretching all the way south to New Zealand.

  • Helens began to develop prior to the end of the Ice Age; the volcano’s earliest ash deposits date back at least 40,000 years ago.
  • The formation of the crater is believed to have occurred during the previous 2,200 years.
  • Helens was the site of nine major eruptions.
  • Goat Rocks was formed between 1800 and 1857 as the result of a major explosion followed by a succession of lesser eruptions.

A Volcanic Giant Rouses

Years before the eruption of Mount St. Helens, modern-day scientists and geologists expressed alarm about the volcano. Some believed that it was the most probable volcano to erupt before the end of the twentieth century, and they were correct. They were absolutely correct. Beginning on March 16, 1980, a sequence of thousands of earthquakes and hundreds of steam explosions (known as phreatic explosions) erupted at Mount St. Helens, causing the mountain’s north side to rise by more than 260 feet in an outward direction.

  1. A 6,000-foot-high ash cloud was blasted into the atmosphere by Mount St.
  2. The ash-spewing volcano continued to erupt until the end of April, generating two massive craters that later combined into a single larger crater.
  3. In response to magma pushing upward into the volcano from deep inside the earth’s crust, Mount St.
  4. There were more earthquakes and more continuous steam explosions, and it became evident that a big eruption was unavoidable, but no one knew when it would happen.

Earthquakes and Landslides

On Sunday, May 18, 1980, early in the morning, volcanologist David Johnston recorded measurements of Mount St. Helens from a nearby observation site, according to historical records. A red flag should have been raised to alert the public of the impending disaster. In the early morning hours of August 22, a magnitude 5.1 earthquake hit one mile beneath the summit of Mount St. Helens, causing the greatest debris landslide in modern history. After successfully transmitting the information, Johnston would unfortunately not make it through the day.

The debris avalanche and mudflows destroyed the volcano’s top and bulge and flowed down the North Fork of the Toutle River. According to the United States Geological Survey, the debris avalanche had a volume equivalent to 1 million Olympic-size swimming pools.

Mount St. Helens Erupts

The debris landslide relieved pressure on the volcano’s magma structure, resulting in large lateral explosions and the ejection of tons of ash, rock, volcanic gas, and steam from the volcano’s vents. Because of the acceleration of the lateral blast, it reached speeds of up to 670 miles per hour and engulfed the region north of the volcano with a swarm of scorching debris covering 230 square miles. The bomb may have reached or exceeded supersonic speed in certain regions, according to some estimates.

Helens, which was designated as a “silent zone,” for some reason.

It razed every tree within a six-mile radius and burned others in addition to destroying them.

Pryoclastic flows, which are fast-moving bursts of lethal superheated volcanic gas and pumice, were also caused by the lateral explosion.

Ash Cloud Circles the Globe

An enormous amount of volcanic ash mushroomed vertically into the air for at least 12 miles, causing lightning and setting forest fires in its wake. The cloud moved at 60 miles per hour and obscured the skies over Spokane, Washington, during the daytime. The eruption’s intense ash emissions persisted until around 5:30 p.m., after which they began to subside the next day. Across the course of the next two weeks, the massive ash cloud transported about 520 million tons of ash over a distance of 22,000 miles to the east.

Death and Destruction

The events that occurred at Mount St. Helens in 1980 converted the immediate surrounding region into a wasteland, wiping out plants, trees, and entire ecosystems in the process. A total of 57 persons were murdered, including volcanologists, loggers, campers, and news reporters in the eruption. According to autopsy records, the majority of the victims perished as a result of thermal burns or breathing hot ash. Some individuals feel the death toll might be far higher and that many unidentified victims were swept up by the debris flow.

  1. Helens, was completely submerged under masses of debris and sludge.
  2. The wildlife in the region was particularly heavily impacted, as was the vegetation.
  3. Local salmon hatcheries were also damaged as a result of the fire.
  4. Furthermore, the flying ash cloud left a wide swath of devastation in its wake.
  5. Because of this, it blocked filters, pumps, and other electrical equipment, leading to extensive power outages.

Getting rid of the settled ash was a massive undertaking that cost millions of dollars and took more than two months to finish, but it was well worth it. The majority of the ash was disposed of in abandoned quarries or landfills. Some of it was kept in reserve for future industrial use.

National Volcanic Monument

The National Volcanic Monument was established in 1982 when Congress designated 110,000 acres of property surrounding Mount St. Helens and within the Gifford Pinchot National Forest as the National Volcanic Monument. A research, recreation, and educational facility, the Monument was established. The ecology within the Monument has been mostly left alone to re-establish itself through natural processes. Visitors may see the volcanic crater of Mount St. Helens, as well as lava domes and other changes in the area.

Spirit Lake has been resurrected, however it is shallower than it was previously.

Thousands of acres of land were reforested following the 1980 volcanic eruption, with about 200 million board feet of dead timber salvaged.

Mount St. Helens Today

Following the May 1980 eruption, Mount St. Helens witnessed a series of further explosions during the summer and autumn. Two of the domes were destroyed by further explosions, which resulted in the formation of fresh lava in the new crater and the formation of additional lava domes. Over the next several years, 17 further blasts occurred, resulting in the formation of a massive lava dome that stood over 820 feet tall and measured 3,600 feet in circumference by 1986. After a long period of inactivity, hundreds of minor earthquakes shook beneath the lava dome in September 2004, forcing magma to begin surging to the surface and erupting into flames.

  1. Several explosions, the most of which were minor, occurred on Mount St.
  2. Between 2005 and 2008, the volcano remained active and erupted with enough lava to fill 36,000 Olympic-sized swimming pools on the crater floor.
  3. Since 2016, geologists have witnessed hundreds of tiny earthquakes beneath Mount St.
  4. It is estimated that at least 40 earthquakes have occurred in the area since the beginning of 2018, with one earthquake measuring 3.9 on the Richter Scale.


The Cataclysmic Eruption of 1980. Volcanic Activity Rebounds in the United States Geological Survey (USGS). 2004-2008. The Forest, according to the U.S. Geological Survey. Gifford Pinchot National Forest is managed by the USDA Forest Service. Mount St. Helens is undergoing a’recharging’ process decades after the catastrophic 1980 eruption. According to ABC News. The eruptions of Mount St. Helens have occurred in the past, present, and future. USGS. The Resurrection of Life: Answers to Frequently Asked Questions About Plant and Animal Recovery After the 1980 Eruption Mount St.

Helens National Volcanic Monument is managed by the USDA Forest Service. St. Helens is a town in the United Kingdom. The Smithsonian Institution’s National Museum of Natural History is located in Washington, DC. The Global Volcanism Program (GVP) was established in 1989.

Explosives reveal Mount St. Helens’ cold heart

The Cataclysmic Eruption of 1980 took place in the Pacific Northwest. 2004-2008 Volcanic Activity Revisited, according to the United States Geological Survey. The Forest, according to the United States Geological Survey (USGS). Gifford Pinchot National Forest, managed by the USDA Forest Service. Mount St. Helens is “recharging” decades after the catastrophic 1980 eruption. This is according to ABC News. Mount St. Helens eruptions in the past, present, and future are all covered in this article: USGS.

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Helens National Volcanic Monument is administered by the USDA Forest Service.

NHMNH (National Museum of Natural History) at the Smithsonian Institution A program to study volcanic activity throughout the world is known as the Global Volcanism Program (GVP).

Mount Saint Helens

Mount Saint Helens is a volcano in the Cascade Range in southern Washington State, United States. In 1980, the volcano erupted in one of the most powerful volcanic explosions ever recorded in North America, the May 18th eruption. Take, for example, the volcanic eruption of Mount Saint Helens and the resulting flooding caused by glaciers that have melted. Mt. Saint Helens erupted in a massive explosion on May 18, 1980, drawing the attention of geologists across the world. Encyclopaedia Britannica, Inc.

  1. View all of the videos related to this topic.
  2. Helens had been dormant since 1857, when it was given its name by the English sailor George Vancouver in honor of a British envoy.
  3. Extensive cracks and the formation of a bulge on the north side of the volcano were produced by pressure from rising magma within the volcano.
  4. The earthquake was felt as far away as Alaska.
  5. The blast reached temperatures of 660 degrees Fahrenheit (350 degrees Celsius) and traveled at speeds of at least 300 miles (500 kilometers) per hour.
  6. Helens were submerged in deep layers of mud and debris that reached as far as 17 miles (27 km) away as a result of mudflows, pyroclastic flows, and floods caused by the avalanche and side-blast.
  7. Complete darkness descended on the city of Spokane, Washington, which is approximately 250 miles (400 kilometers) northeast of the volcano.

It is not known which nation the Southern Alps are located in.

An estimated 57 humans were killed, as well as thousands of animals, in the May 18 incident, and trees covering an area of approximately 200 square miles (500 square kilometers) were blown down by the lateral air blast.

Helens’ volcanic cone, which stood 9,677 feet (2,950 metres) high at the time of the eruption (2,549 metres).

Scattered earthquakes and minor explosions happened again between 1989 and 1991 (including a few of small explosions), then again in 1995 and 1998.

Michael Hynes is a musician and songwriter from Los Angeles, California.

Helens National Volcanic Monument was established in 1982 over 172 square miles (445 square kilometers) of land surrounding the volcano, which is maintained by the United States Forest Service as part of the Gifford PinchotNational Forest.

There are also several recreational and educational possibilities available at the monument.

There are additional possibilities to see animals and plants that have returned to the explosion zone on the west side, along with lakes that have developed as a result of the eruption on the east side.

Several lava structures of varying ages may be seen on the south side, including the longest continuous lava tube in the 48 conterminous United States, which was produced during an eruption around 2,000 years ago.

Mount Saint Helens, in the state of Washington. Michael Hynes is a musician and songwriter from Los Angeles, California. Those in charge of editing the Encyclopaedia Britannica Adam Augustyn was the author of the most recent revision and update to this article.

Mount St. Helens

Prior to 1980, Mount St. Helens had created a conical, young volcano dubbed as the Fuji-san of America because of its conical shape. During the 1980 eruption, the highest 400 meters of the summit were destroyed by slope collapse, producing a horseshoe-shaped crater of 2 x 3.5 kilometers in size that is now partially filled by a lava dome. Since its formation around 40-50,000 years ago, Mount St. Helens has been the most active volcano in the Cascade Range, and it has been the most active volcano in the United States during the Holocene epoch.

  1. St.
  2. Aerial view of the contemporary structure.
  3. Historical eruptions on the north slope of the volcano began in the 19th century and were seen by early inhabitants in the Goat Rocks area on the north flank.
  4. Helens website maintained by the United States Federal Government, or see below for additional information!
  5. Helen’s Mt.
  6. Helens summit panoramas captured by Dan Taylor and his crew at Studio 360 have been made available online for everyone to see and enjoy.
  7. Amazing photos, and excellent effort!
  • To see a current panorama of MSH, please visit this page. Click here to see a panoramic view of MSH taken in 2003. To see a comparison between 2003 and 2006, click here. More breathtaking panoramas from the staff at Stromboli Online may be found by clicking here.

Our close buddy and VW alum Prabhu Ram just gave us many wonderful MSH photographs, which we are pleased to share with you. To view his images, please visit this page. Dr. Shan de Silva, a resident volcanologist at VW, traveled to MSH in August 2006 to take some exclusive high-resolution close-up images of the crater’s interior and surrounding area. To view his images, please visit this page.

Mount St. Helens isn’t where it should be. Scientists may finally know why.

The frigid volcanic peaks of the Pacific Northwest rise from the jumbled landscape east of Interstate 5 in an amazingly straight line, defying the odds. However, there is one volcano that stands out as being out of place. Mount St. Helens, located in the southwest corner of Washington State, is more than 25 miles to the west of the other exploding peaks in the region. It’s been 40 years since Mount St. Helens famously erupted, blasting ash and gas 15 miles into the sky, destroying 135 square miles of forest, and killing 57 people in the country’s bloodiest volcanic explosion in recorded history.

  1. The source of all this weaponry, on the other hand, has remained a secret for decades.
  2. ‘There really shouldn’t be a volcano where Mount St.
  3. The goal of resolving this problem is more than only to satisfy geologic curiosity.
  4. During the decades that have followed, scientists have used the considerable data gathered from that explosion to better understand volcanic eruptions around the world and to prepare for those that are yet to occur.
  5. ” Importantly, a more complete understanding of the volcano’s inner workings may enable researchers to better follow the shudders and shifts that herald an eruption, perhaps allowing them to improve volcanic predictions and get people out of harm’s way before an eruption occurs.
  6. Helens, scientists are now uncovering some hints as to why the volcano is in such an unusual location.
  7. Helens, or iMUSH for short, was one of the most comprehensive efforts to trace a volcano’s origins ever undertaken.
  8. In general, the volcano does not conform to the classic idea of a crater over a chamber of molten rock, as is commonly believed.

The cloud of partly molten blobs appears to be floating deep beneath the surface, skewed to the east, toward adjacent Mount Adams, and it appears to be lingering there for some time.

View from the sky

On the bright, clear morning of May 18, 1980, geologists Dorothy and Keith Stoffel were flying over Mount St. Helens and taking in the spectacular vistas. To commemorate Dorothy’s forthcoming 31st birthday, the couple had obtained permission from the United States Geological Survey (USGS) to charter a flight above the volcano. The mountain had been rumbling for over two months, yet it was almost completely silent early on that Sunday morning. When Dorothy contacted the United States Geological Survey to see whether the trip was still on, she was told: “Come on over, there’s nothing going on here.” Because of the recent volcanic burbles, Mount St.

  • The Cessna 182’s windows provided an excellent vantage point for taking shots of the symmetrical top.
  • Because it began growing in late March of that year, the bulge has expanded six and a half feet each day since then.
  • In the next moments, the plane swung around in the sky, finally making two passes above the crater of the volcano.
  • It was at this point that the volcano began to collapse.
  • Before anyone could fathom what was occurring, the mountain was split in half.
  • “Volcanoes erupt, that’s something you expect as a geologist,” Dorothy explains.
  • The landslide relieved pressure on the magma chamber under the surface, much like popping the cork of a champagne bottle, and the volcano sprang into life.

The explosion, which was traveling at speeds of up to 300 miles per hour, blasted the volcano’s summit off and spread havoc across hundreds of square kilometers.

In order to gain speed, the pilot dipped into a nosedive.

However, by deviating to the south, the trio was able to narrowly avoid capture.

More than nine hours, the plume towered over the volcano, blanketing the surrounding area in ash and completely blocking out the sunlight.

Climber John Christiansen, on the summit of Mount Adams, about 34 miles to the east, hoisted his ice ax to the heavens.

On Oregon’s Sauvie Island, 45 miles to the southwest, artist Lucinda Parker and her husband monitored the swirling plume while their three-year-old daughter played in the beach nearby.

The force of the explosion has reverberated down through the centuries, attracting volcanologists from all over the world to Washington State to examine the volcano. Part of the inspiration for the iMUSH project came from this deep curiosity.

Peering into the deep

Mount St. Helens is a volcano on the Cascadia volcanic arc, which extends from British Columbia to Northern California and is the most active volcano in the world. Like many volcanoes across the world, this simmering range is a tectonic collision zone caused by the subduction of an oceanic plate beneath a more buoyant continental plate, as is the case with this particular volcano. As the slab descends, pressures and temperatures rise, and fluids percolate out of the slab, causing the solid mantle rocks to melt.

  1. It is above these locations, when the falling slab falls to around 62 miles deep and temperatures rise to levels conducive to magma formation, that the majority of Cascade volcanoes—and others across the world—take shape.
  2. Helens, on the other hand, is in a different predicament.
  3. The iMUSH project, which began in the summer of 2014 with the goal of resolving this problem, was launched in part to address this issue.
  4. Hundreds of researchers gathered to deploy a fleet of seismometers all over the volcano’s sides, despite the challenges of flat tires and poorly maintained dirt roads.
  5. During the same time period, another set of equipment recorded every tremor that occurred around the peak, including the rumbling of ocean waves and earthquakes on the other side of the planet.
  6. Other researchers approached the system from a different angle, by investigating the chemistry of the rocks.
  7. “As far as we were allowed to go, we threw everything we had at Mount St.
  8. The findings suggest that seismic waves move slowly in a zone east of Mount St.
  9. Magnesium, for example, can slow down seismic waves due to differences in mineral composition, although magma can also slow down seismic waves.
  10. Helens, according to the research.
  11. According to Dawnika Blatter, an experimental petrologist with the USGS’ California Volcano Observatory and a member of the iMUSH team who works with the California Volcano Observatory, the team discovered that the sticky gas-rich magmas that give Mount St.

Geoffrey Abers, a geophysicist at Cornell University who was involved in the iMUSH seismic analysis, says the unexpected offset of this magma “suggests we need to investigate more extensively than simply just below a volcano if we’re going to understand where the magma is coming from.” Following the 1980 eruption, geologists may have even detected tremors emanating from this deep melt zone, as the earth adapted to the draining of molten rock from under the surface.

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Moran claims that tremors continued to rumble to the southeast of the summit for over a year after the explosion.

Helens’ magma pockets could aid in directing future monitoring efforts.

According to Moran, “we’ve known for some time that the southeastern side of St. Helens is a little bit of a weak area in the network.” Knowing the reasons for earthquakes that happen on the other side of the volcano gives us additional motivation to work on that side of the volcano.”

Ancient scars

The identity of the choreographer of this magmatic dance is still out in the air. In the surrounding environment, which is scarred by millions of years of tectonic upheaval, many scientists believe they can find signs that will help them better understand how the present flow of molten rock will be directed. Siletzia was a volcanic plateau that formerly existed off the shore of North America’s west coast. However, the Earth’s ongoing tectonic shifting gradually reduced the distance, and Siletzia crashed with the continent around 50 million years ago.

  • It is possible that an indelible tectonic suture can be found close under Mount St.
  • The scientists used a technique known as Magnetotellurics, which measures the conductivity of rocks, to sketch out the structures that resulted from this merging.
  • Helens, marking the location where ancient sea sediments were transformed into a special rock type known as metasedimentary.
  • The experts believe that this rock is a slug of lava that has cooled over time and developed millions of years before Mount St.
  • This volcanic block, known as a batholith, and the metasedimentary rocks of the suture zone have different characteristics, and the changes in these properties may cause the stresses in the area to change and, in turn, control the magma flow.
  • Helens by the batholith; nevertheless, metasedimentary rocks may act as a relief valve, pulling the volcano’s sticky, viscous magma to the surface.

Navigating a sea of data

While the iMUSH studies have helped to improve our image of the deep interior of the planet, Moran points out that the picture is far from comprehensive. “When it comes to geophysical imaging, one of the fundamental laws is that the deeper you go, the less you know.” Today, the ruins of Siletzia may only be seen in fragments on the surface, partially hidden by flows of now solidified lava and soils densely populated with trees, and partially buried by flows of now solidified lava. As a result, experts are contesting the precise location of the suture zone, as well as its significance in magmatic direction.

  1. Helens, according to seismologist Eric Kiser of the University of Arizona, who was a member of the iMUSH team.
  2. They aren’t the only ones, though.
  3. What is the rate at which the magma moves?
  4. Helen Janiszewski, a seismologist at the University of Hawaii at Manoa, explains that each potential answer contributes to our understanding of how and why volcanoes erupt.
  5. Since that fatal day in 1980, Mount St.

This convergence highlights the need of keeping a careful eye on this specific peak, and scientists have relished the challenge of doing so. According to Kiser, “Mount St. Helens is being monitored really closely.” “The folks from the USGS, they’ve got it all under control.”

A Timeline of Mount St. Helens

One day before the eruption, on May 17, 1980, the volcano erupted. Data image selection is specified by the attribute ” data-image-selection=” “> One day before the eruption, on May 17, 1980, the volcano erupted.

►~300,000 years ago

Mount St. Helens, also known as Loowit Volcano, is a stratovolcano that developed when the Juan de Fuca tectonic plate subducted into the North American plate.

~1850 BCE

Scientists believe this is the volcano’s largest eruption ever, erupting 5–10 cubic kilometers of material, which is around five to ten times larger than the eruption that occurred in 1980.

~ 1000 BCE

Mount St. Helens is formed as a result of a sequence of lava flows, making it younger than the Great Pyramids of Giza, which were built more than 5,000 years ago.


The summit is named after a fellow Britishman, Alleyne Fitzherbert, Baron St. Helens, by explorer George Vancouver. It had been known as Lawetlat’la, or “smoker,” by the nearby Native American tribe for a long time. Spirit Lake, around the summer of 1968. In the summer of 1968, Spirit Lake was photographed. ” data-image-selection=” “>


A camping and fishing location, Spirit Lake, at the foot of the mountain is flanked with cabins, a YMCA camp, and the Mount St. Helens Lodge, which is operated by the colorful World War I veteran Harry Truman, who died in the war (nope, no relation).

March 27, 1980

When steam begins to flow from the mountain’s crater near the summit, it signals the commencement of an eruption. It was preceded by a series of minor earthquakes, which indicated that magma was flowing deep inside the earth.

Spring 1980

David A. Johnston, a 30-year-old volcanologist with the United States Geological Survey (and University of Washington PhD graduate), is among the geologists who have converged on Vancouver, Washington. No one has ever had the opportunity to observe an eruption like this up close before.

April 1980

Red (hazardous) and blue (permitted employees only) zones are established around the mountain, and most locals are evacuated, yet 83-year-old Truman refuses to leave his cottage with 16 cats, which he shares with his wife. David Johnston’s last photograph was shot on May 17, 1980, when he passed away. It was decided that this spot will be renamed Johnston Ridge in his honor in the future. Data image selection is specified by the attribute ” data-image-selection=” “> David Johnston’s last photograph was shot on May 17, 1980, when he passed away.

►May 18, 1980

5.1-magnitude earthquake shakes the world on a bright Sunday morning, prompting the greatest landslide in recorded history and the largest lateral outpouring of lava, which flattens 600 square kilometers of woodland. As he is being murdered instantaneously by the bomb, Johnston, situated on a ridge close to the north, radios his colleagues: “Vancouver, Vancouver, this is it!” Johnston is killed instantly by the blast.

May 18, 1980

Fifty-seven individuals die, the majority of them from asphyxiation, primarily in locations beyond the red and blue zones, with the majority of them going fishing, camping, or hiking.

A lahar, sometimes known as a mud flow, is rushing down the Toutle River. Column of lava from the eruption on May 18, 1980. the=”data-image-selection=” “> the=” data-image-selection=” Column of lava from the eruption on May 18, 1980.

►May 18, 1980

The eruptive episode comes to a close around nine hours later, when a column of ash rises 18 miles into the air and approximately 1,300 feet of mountain is blown off, bringing Mount St. Helens’ height down to 8,366 feet.

May 1980

Ash blankets the Pacific Northwest and drifts as far east as Wyoming; a total of 540 million tons of ash fall in a single year in the region.

Summer 1980

Smaller eruptive activity will continue into October, giving geologists the opportunity to examine a large eruption up up and personal. A few visitors from the volcano hotspot of Hawaii cook a pig on the pyroclastic flow, also known as the searing hot gas emissions, as others watch. It is still customary for USGS Cascades Volcano Observatory scientists to have an annual BBQ, albeit in someone’s back yard.)


Mount St. Helens is designated as the first National Volcanic Monument in the United States by Congress.


The eruption series that began in 1980 has taken on a completely different appearance than the one that began in 1980. These eruptions involve plumes of ash and lava extrusion that eventually form a dome 1,000 feet in height, despite the fact that they are less immediately striking.


Mount St. Helens has reconstructed around 7% of the mass that was lost during the catastrophic 1980 eruption.

Explaining the location of Mount St Helens – Geographical Magazine

One of the most intriguing, yet deceptively basic, issues that surround the legendary Mount St Helens volcano, which erupted with such ferocity in May 1980, is: Why is the volcano located in the location that it is? The major Cascade arc of volcanoes (produced by the subduction of the Juan de Fuca Plate beneath North America during the past 40 million years) is located in the southwest corner of Washington state and is a very straight line that includes such peaks as Mount Adams, Mount Rainer, and Goat Rocks.

In addition to being “out of line,” Mount St Helens is also the most active volcano in the Cascade Range, according to the National Geographic.

Now, using seismic sound waves and magnetotelluric data (electrical conductivity under the surface), USGS and Oregon State University geophysicists have discovered a massive subterranean rock structure known as a ‘batholith’ near the Cascadia arc that is preventing magma from rising.

“Magma is thought to “stall” in the crust below the batholith, where ascending is difficult.” On the other hand, when there are cracks in the crust, such as those found under Mount St Helens, magma can rise more quickly.’ A release valve for the pressure that develops beneath the batholith is created by what he refers to as “an old tectonic scar” beneath Mount St Helens, according to the volcanologist.

The ability to predict future eruptions – which has traditionally relied on observations of the bulging dome and seismic activity that occurred prior to the 1980 catastrophe – may now be more precise, as researchers track the movement of magma beneath the surface of the Earth.

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Mount St. Helens Facts for Kids

Quick facts for kids Mount St. Helens
3,000 ft (1 km) steam plume on May 19, 1982, two years after its major eruption
Highest point
Elevation 8,365 ft (2,550 m)
Prominence 4,605 ft (1,404 m)
Location Skamania County, Washington,U.S.
State/Province US-WA
Parent range Cascade Range
Topo map USGSMount St. Helens
Age of rock 40,000 yrs
Mountain type Activestratovolcano
Volcanic arc Cascade Volcanic Arc
Last eruption 2004 – July 10, 2008
First ascent 1853 byThomas J. Dryer
Easiest route Hike via south slope of volcano (closest area near eruption site)

Mount St. Helens is a volcano in the state of Washington, United States. stateofWashington. It’s located 96 miles (154 kilometers) south of Seattle and 53 miles (85 kilometers) northeast of Portland, in the state of Oregon. Located in the Cascade Rangeofmountains, the volcano is active. It is a member of the Cascade Volcanic Arc, which is part of the PacificRing of Fire and has over 160 active volcanoes. Mount St. Helens was originally known as Louwala-Clough, which translates as “smoking mountain” or “fire mountain” in the language of the Native AmericanKlickitatpeople.

  • In 1982, the United States President Ronald Reagan and the United States Congress established the Mount St.
  • The 1980 eruption was the deadliest and most economically destructive volcanic event in the history of the United States, resulting in the deaths of 57 people and the destruction of $1 billion in economic output.
  • An earthquake measuring 5.1 on the Richter scale generated a massivedebrisavalanche that covered a large area.
  • Because of a quick influx of magma from the Earth’s mantle, the earthquake was created.


Mount St. Helens was the fifth-highest mountain in Washington State prior to the eruption that occurred in 1980. At its highest point, the summit rises more than 5,000 feet (1,525 meters) above its base, where it is formed by ridges that surround it. In contrast to the neighboring hills, it stood out because of its symmetrical cone shape and the blanket of snow covering the summit. As a result of its cone-shaped appearance, it has been dubbed the “Mount Fuji of America,” in reference to the famousMount Fuji, which is a national emblem ofJapan.

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Modern eruptions

On May 18, 1980, at 8:32 a.m. Pacific Daylight Time, Mount St. Helens erupted, causing widespread devastation. In the months leading up to the massive eruption that occurred on May 18, 1980, there were several signals of volcanic activity on the island. On March 20, 1980, Mount St. Helens was the epicenter of an earthquake with a magnitude of 4.2. The eruption of the volcano began on March 27 with the release of steam. By the end of April, the northside of the volcano had begun to erupt and develop in size.

  1. It was the greatest known debris avalanche in the history of recorded time.
  2. Helens erupted at 8:32 a.m.
  3. The eruption was given a rating of five on the Volcanic Explosivity Indexscale, which is the same grade as the famousVesuviuseruption that occurred in 79AD.
  4. A “plume” is the term used to describe the cloud that rises from a volcano.
  5. The ash moved eastward at a speed of around 60 miles per hour (95 kilometers per hour), with some ash reaching Idaho at 12:00 pm, nearly 3.5 hours after the eruption began.
  6. A series of lesser eruptions occurred throughout the night and for several days afterwards.
  7. Helens resulted in lahars, or volcanic mudflows, which were triggered by the collapse of the northern flank of the volcano.
  8. Many trees were killed and bridges were destroyed as the lahars traveled for miles down the Toutle and Cowlitz rivers.
  9. The eruption of Mount St.
  10. In all, it emitted more than 0.67 cubic miles (2.8 cubic kilometers) of ash and other debris.
  11. Helens’ height was reduced by approximately 1,300 feet (400 meters) as a result of the collapse of the north slope of the volcano, which created an avolcanic craterone to two miles (1.6 to 3.2 kilometers) broad and half a mile (800 meters) deep.

The eruption claimed the lives of 57 humans as well as roughly 7,000 game animals (deer, elk, and bear) and around 12 million fish from a nearby fish farm. There were nearly 200 homes burned or severely damaged, as well as 185 miles (300 km) of roadway and 15 miles (24 km) of railroad.


More volcanic activity persisted at Mount Saint Helens between 1980 and 1986, resulting in the formation of a new lava dome in the crater. Several tiny explosions and eruptions occurred, resulting in the formation of new lava domes. In two periods, from December 7, 1989 to January 6, 1990, and from November 5, 1990 to February 14, 1991, the volcano erupted, spewing ash into the atmosphere, at times in massive clouds. The ash spread across several states, reaching as far east as Montana and as far south as Colorado.

2004 to present activity

This photograph shows the “Whaleback” as it appeared in February 2005. On March 8, 2005, a plume of 36,000 feet was observed. On or around October 11, 2004, magmabubbles rose to the summit of the volcano, and a second lava dome was formed on the south side of the original dome’s summit. Throughout 2005 and into 2006, this new dome rose in size. A number of novel phenomena were observed, including the “whaleback,” which is solid magma that is being forced to the summit of the volcano by magma beneath the surface.

  • During a rockfall on July 2, 2005, the top of the whaleback snapped off, sending hundreds of meters of ash into the air above the volcano.
  • Helens, signaling the beginning of a new phase of activity for the volcano.
  • This very minor eruption occurred as a result of the formation of a new lava dome and the occurrence of a magnitude 2.5 earthquake.
  • The big volcanic rock, which was about half the size of a football field, was being pushed upward at a rate of up to 6 feet (2 meters) every day.
  • The lava dome was breached on October 22, 2006, at 3:13 p.m.
  • The following collapse and avalanche created an ash cloud 2,000 feet (610 meters) above the crater, but it rapidly dissipated and did not cause any damage.
  • However, according to the Cascades Volcano Observatory of the United States Geological Survey, there was no substantial ash cloud, indicating that the eruption was not a volcanic eruption.

Human history

Numerous accounts from Native American folklore have been used to explain the eruptions of Mount St. Helens and other Cascade volcanoes, like the one above. The most well-known of them is theBridge of the Godsstory, which was recounted by the Klickitat people in their own words. According to the legend, the chief of all the gods, Pahto (also known as Klickitat), and his two sons, Pahto (also known as Wy’east), went down the Columbia River from the Far North in search of a suitable spot to dwell.

  1. The two boys were fighting over the land, so their father used his great bow to resolve the conflict by shooting two arrows — one to the north and one to the south – from opposite directions.
  2. The leader of the gods then constructed the Bridge of the Gods, allowing his family to gather on a regular basis.
  3. The two young leaders battled for her, burying entire towns and woods in the midst of their battle.
  4. To punish them, the gods’ supreme leader killed each of the lovers and converted them into enormous mountains, where they perished.
  5. Mount Adams was transformed into Pahto, who had his head inclined in the direction of his lost love.
  6. Helens was formed from the lovely Loowit, which was known to the Klickitats as Louwala-Clough, which translates as “smoking or flaming mountain” in their language (the Sahaptin call the mountain Loowit).

The mountain (which they refer to as “Lawetlat’la,” which roughly translates as “the smoker”) is considered to be of special spiritual significance by them, and it appears significantly in their creation narrative as well as in some of their songs and rituals, as well as in their songs and rituals.

Other tribe names for the mountain include “nh’ák'” (“water pouring out”) from the Upper Chehalis and “aka akn” (“snow mountain”) from the Kiksht, which means “snow mountain” in English.

Exploration by Europeans

On May 19, 1792, while exploring the northern Pacific Oceancoast, the Royal NavyCommander George Vancouver and the officers of HMS Discovery made the first documented observation of Mount St. Helens in the history of the Europeans. On October 20, 1792, after the Discovery crossed into the mouth of the Columbia River, Vancouver named the peak for British diplomat Alleyne Fitzherbert, 1st Baron St Helens. The mountain was first seen when the Discovery entered into the mouth of the Columbia River.

  1. Geologists and historians discovered only later that the eruption occurred in 1800, marking the beginning of the 57-year-long Goat Rocks Eruptive Period, which began with the eruption (seegeology section).
  2. Members of the Lewis and Clark Expedition sighted Mount St.
  3. It was reported, however, that quicksand and choked channel conditions existed at the mouth of theSandy Rivernear Portland, indicating that Mount Hood had erupted at some point in the preceding decades.
  4. Kelley spearheaded an effort to rename the Cascade Range as the President’s Range, as well as to rename each major Cascade peak after a past President of the United States of America Mount St.

European colonization and use of the area

A fur trapper operating in the Mount St. Helens region is seen in a 19th-century photograph. While working for the Hudson’s Bay Company at Fort Vancouver in March 1835, Meredith Gairdner gave the first recorded non-Indigenous eyewitness testimony of a volcanic explosion, which was later confirmed by other witnesses. He wrote a letter to the Edinburgh New Philosophical Journal, which published it in January 1836, detailing his experiences. On a sailing trip with the United States Exploring Expedition in 1841, Yale University’s James Dwight Dana witnessed the quiescent peak, which was located just outside the entrance of the Columbia River.

  1. Paul Kane’s painting is on display.
  2. Helens in the middle of the night following his 1847 visit to the region The so-called Great Eruption occurred in the late fall or early winter of 1842, and it was observed by adjacent European residents and missionaries.
  3. The eruptions that occurred during this time period were most likely phreatic (steam explosions).
  4. Helens.
  5. In October 1843, future California Governor Peter H.
  6. According to legend, the injured man sought care at Fort Vancouver, although the fort’s commissary steward at the time, Napoleon McGilvery, maintained he had no knowledge of the occurrence and denied any involvement.
  7. Warre drew the scene, and two years later, Canadian painter Paul Kane painted watercolors of the softly smoking mountain in the background.
  8. Photograph of a hiker on the summit of Mount St.
  9. Volcano St.
  10. The lack of a considerable ash layer connected with this event implies that it was a minor eruption.

This was the first confirmed volcanic activity since 1854. Before the 1980 eruption,Spirit Lakeoffered year-round leisure opportunities. In the summer there was boating,swimming, andcamping, while in the winter there wasskiing.

Human impact from the 1980 eruption

57 individuals were murdered as a result of the eruption, according to reports. Instead of occurring on a Sunday, the eruption might have occurred one day later, when loggers would have been at work, and therefore the death toll may have been far greater. Eighty-three-year-old When President Harry R. Truman, who had lived near the mountain for 54 years, opted not to leave before the oncoming eruption, despite numerous warnings from local officials, he became renowned. After the explosion, no trace of his corpse was ever recovered.

  1. Johnston, a 30-year-old volcanologist who was stationed on the neighboring Coldwater Ridge at the time of the eruption, was also killed in the eruption.
  2. It’s finally here!” The corpse of Johnston was never located.
  3. However, when contrasted to what’s up there, the moon appears to be more like a golf course.” Atop May 23, a film team led by Seattle filmmaker Otto Seiber was dropped by helicopter on Mount St.
  4. Seiber was the director of photography.
  5. It was on May 25 that a second eruption occurred, but the crew managed to live and was rescued two days later by National Guard helicopter pilots.
  6. Helens, had been turned into a popular documentary.

Protection and later history

View of the hillside at the David A. Johnston Observatory (named for David A. Johnston), taken on July 30, 2005, 25 years after the volcano’s outburst. The view of Johnston Ridge from a nearby site on 16 July 2016, 36 years after the eruption, demonstrates the persistence of plant life. As part of the Mount St. Helens National Volcanic Monument, which encompasses 110,000 acres (45,000 ha) surrounding the summit and within the Gifford Pinchot National Forest, President Ronald Reagan and members of the United States Congress established the monument in 1982.

The United States Forest Service reopened the peak to climbing in 1987.

The most prominent restriction was the shutdown of the Monitor Ridge path, which formerly allowed up to 100 approved hikers per day to get to the top of Mount Whitney.

In February 2010, a climber was killed after he fell from the rim of the crater into the crater.

This section of the path runs from the South Fork Toutle River on the west to Windy Pass on the east, and it is a restricted zone where camping, bicycling, dogs, campfires, and off-trail excursions are not permitted.

This article’s citation is: Mount St. Helens Facts for Kids. The free encyclopedia Kiddle Encyclopedia

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