Where Is Mt Saint Helens

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.

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Helens had been dormant since 1857, when it was given its name by the English sailor George Vancouver in honor of a British envoy.

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.

  1. The earthquake was felt as far away as Alaska.
  2. The blast reached temperatures of 660 degrees Fahrenheit (350 degrees Celsius) and traveled at speeds of at least 300 miles (500 kilometers) per hour.
  3. 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.
  4. Complete darkness descended on the city of Spokane, Washington, which is approximately 250 miles (400 kilometers) northeast of the volcano.
  5. It is not known which nation the Southern Alps are located in.
  6. 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.
  7. 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.

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.

  1. 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.
  2. 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.
  3. 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.
  4. 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.
  5. 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 Visitor Center

Call (360) 274-0962 to make an appointment at 3029 Spirit Lake Highway in Castle Rock, Washington.


From March 1 through May 15, the museum is open Monday through Friday from 9 a.m. to 4 p.m. From May 16 to September 15, the museum is open everyday from 9 a.m. to 5 p.m. From September 16 through October 31, the museum is open daily from 9 a.m. to 4 p.m. From November 1 to February 28, the museum is open from 9 a.m. to 4 p.m. on Thursdays through Mondays. The center is closed on the following days in respect of the holidays:

  • New Year’s Day, Martin Luther King Jr. Day, Presidents’ Day, Veterans Day, Thanksgiving and the Friday following Thanksgiving, and Christmas are all holidays.


The Mount St. Helens Visitor Center at Silver Lake charges the following admission fees:

  • Ages 6 and under are free
  • Ages 7 to 17 are $2.50
  • Ages 18 and up are $5
  • And a family of four is $15 (two adults and any accompanying youngsters). Tour buses cost $165 each bus.

A variety of State Parks passes are accepted at the Silver Lake Visitor Center, including the following:

  • Seniors with low financial resources pay half the regular fee
  • Disabled people pay half the regular price
  • Disabled veterans pay nothing.

Educational groups

Schools and educational groups from kindergarten to university are exempt from paying entry fees provided they have pre-registered and have completed an assignment linked to the science and history of the region during their visit. If you would want to register a school group for a visit, instructors must fill out thegroup registration form (PDF) and send it to the park personnel through email. A confirmation email will be issued to you once your request has been approved. Students and teachers can arrange for guided tours and discussions with park rangers at the Mount St.

Helens Visitor Center or in the classroom. More information may be obtained by calling 360-274-0962. Please see the links below for example curricula, ideas, and tasks to do in preparation for your visit:

  • Grades K-2
  • Grades 3-5
  • Middle and High School
  • Pre-visit Lesson: Middle and High School
  • Activity Sheet: Grades K-2
  • USGS Mount St. Helens Publications
  • USGS Mount St. Helens Public

Tour Groups

A valid Commercial Use Permit is required for any tour groups visiting the Mount St. Helens Visitor Center that are not part of a K-12 or university setting. During the time that the tourist center is closed for refurbishment, the fee is $100 per bus. When visiting this place, there is no permit charge per person to be paid. At this site, you will not be needed to use your Discover Pass. Visiting tour groups should contact the Interpretive Center early in the season with their preferred tour dates for the year, advise the staff.

To submit an application, please visit this page.

Nearby visitor centers

Located in Silver Lake, the Mount St. Helens Visitor Center is one of six Mount St. Helens Interpretive Centers that can be found along the Spirit Lake Highway that provide information on the volcano. The Weyerhaeuser Forest Learning Center, which is operated by the company, is located at milepost 37. At milepost 43, you’ll find the Mount St. Helens Institute’s Science Learning Center, which is open to the public. Mt. St. Helens National Volcanic Monument’s Johnston Ridge Observatory, which is administered by the United States Forest Service, is located at milepost 52; for additional information on this facility, please see the Mount St.

For information on organizing field trips, visit theirTeacher’s Corner page.

Mount St. Helens National Volcanic Monument

A 5.1-magnitude earthquake rocked the Pacific Northwest on May 18, 1980, causing the eruption of Mount St Helens. The north face of this towering symmetrical peak fell in a tremendous rock debris avalanche at 8:32 am on Sunday morning, May 18, 1980. It took only a few seconds for this massive block of rock and ice to crash into Spirit Lake, then thunder down the Toutle River for 14 miles, crossing a peak 1,300 feet high. The avalanche released pressured gases that had been building up inside the volcano in a short period of time.

  1. Almost 150 square kilometers of woodland was blown over or left dead and standing as a result of the storm.
  2. The volcano was scraped on all sides by slurries of rock and dirt that were wet and cement-like.
  3. However, Mount St.
  4. There was once a lush forest on the slopes of Mount St.
  5. The National Volcanic Monument, which encompasses 110,000 acres and was established by the President and Congress in 1982 for the purposes of study, enjoyment, and education.
  6. Start your tour at one of the Monument’s visitor centers or information stations, which are conveniently located throughout the park.
  7. Consult with park staff about the scheduling of informative tours and talks, as well as theatrical shows that discuss the geology, biologic, and cultural history of the region.

There are several overlooks and miles of paths to explore by car or on foot, and you may do it year-round.

Click here for more information.

Helens area to experience the splendor of winter.

Permits are necessary at elevations more than 4,800 feet year-round.


Extruding from the volcano were thick, pasty lava outbursts that piled on top of one another like pancakes in a messy pile.

The lava dome has now reached a height of 920 feet. Scientists from the United States Geological Survey (USGS) are continuing to monitor the volcano for tremors, swelling, and gas releases.

Anniversary of the Mount St. Helens eruption

In the world of science today: In the early morning hours of May 18, 1980, Mount St. Helens had a devastating and fatal eruption that resulted in the greatest landslide in recorded history. Early this year, hundreds of tiny tremors, steam venting, and a developing bulge projecting 450 feet (140 meters) from the volcano’s summit suggested that magma was rising under the surface. An earthquake of 5.1 magnitude struck the mountain at 8:32 a.m. local time on this day 41 years ago, initiating the massive eruption that resulted in the fall of the volcano’s northern slope and the subsequent avalanche.

  1. 230 square miles of land was entirely devastated in a period of five to nine minutes, according to a geologist with the United States Geological Survey (USGS) who recounted the deadly blast.
  2. 57 individuals were murdered, including volcanologist David A.
  3. Helens erupted on May 18, 1980, killing 57 people.
  4. While the Observatory itself remains closed until further notice, with no definitive opening date in sight, the plaza area behind the structure, which has a spectacular view of the crater and volcano, as well as the blast zone, is now open as of May 10, 2021.
  5. Helens was shot seven years before the explosion that caused its devastation in 1980.
  6. Following the explosion of Mount St.
  7. Image courtesy of Lyn Topinka/USGS.
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The intense heat also wreaked havoc on trees that were located further out from the inner blast zone.

Over the course of several decades, this region has slowly regained its vibrancy.

Helens explosion, this aerial image of timber blowdown was captured on June 8, 1980, shortly after it was completely leveled.

On April 20, 2015, Mount St.

More information about this image may be found at the NASA Earth Observatory.

As ice and snow on Mount St.

Homes, roads, and bridges in adjacent settlements were severely destroyed by the huge lahars generated by the 1980 eruption.

Helens, carrying logs, vehicles, and whatever other debris in its path with it.

Olson/National Park Service.

Helens is an 8,363-foot (2,550-meter) high stratovolcano in Skamania County, Washington, that is approximately 1,300 feet (400 meters) shorter than it was prior to its 1980 eruption.

In the Cascade Range, which runs along the northern coast of North America, it is the most active volcano, and it is also the most active volcano in the world.

Despite its age, Mount St.

The Mount St.

The Cascades Volcano Observatory keeps a close eye on Mount St.

During the eruption of Mount St.

Photograph courtesy of Oman/Combs/National Park Service.

Helens volcano erupted in a catastrophic eruption on May 18, 1980, killing 57 people and causing significant damage to the surrounding terrain.

More videos of the Mount St. Helens eruption may be seen here. Although magma is rising within Mount St. Helens, no eruption is forecast. Mount St. Helens has been reclaimed by life, as seen from space. The Ring of Fire is what it sounds like.

Deanna Conners

Articles may be found here.

About the Author:

In addition to a Ph.D. in Toxicology, Deanna Conners holds an M.S. in Environmental Studies and is a member of the American Chemical Society. Her fascination with toxicology derives from her upbringing in the vicinity of the Love Canal Superfund Site in New York. Her current job involves disseminating high-quality scientific information to the general public and decision-makers, as well as assisting in the establishment of cross-disciplinary collaborations that will aid in the resolution of environmental challenges.

Kelly Kizer Whitt

Articles may be found here.

About the Author:

In her more than two decades of professional experience, Kelly Kizer Whitt has focused her writing on science and technology, particularly astronomy and space exploration. She began her professional career as an editor at Astronomy Magazine, and she has since made frequent contributions to a variety of publications, including AstronomyToday and the Sierra Club. Solar System Forecast, a children’s picture book, was released in 2012 by Scholastic. She has also authored a young adult dystopian novel titled A Different Sky, which is set in the near future.

Kelly currently resides in Wisconsin with her family.

Mount Saint Helens – Hiking in Portland, Oregon and Washington

Mount Saint Helens is a volcano in Washington state. A plaque honors the 57 persons who perished in the 1980 eruption of Mount St. Helens. (Image courtesy of Jeff Statt) Since October 2004, the height of this spine has increased from nothing to several thousand feet in height. (Image courtesy of Jeff Statt) At the rim of the crater, a climber is taking a break. Mount Adams may be seen in the distance. (Image courtesy of Jeff Statt) From the top of the mountain, a view into the crater. In the backdrop, you can see Spirit Lake, which is densely covered with trees.

Helens in the days leading up to the 1980 eruption.

  • In the United States, latitude is 46.19761, longitude is -122.19225, and maps are provided by Oregon Hikers Maps. Elevation: 8365 feet, according to Google Maps.

Hiking information for the Monitor Ridge route may be found on the Mount Saint Helens Hiking page.

Volcanic History

Mount St. Helens is the newest member of the volcanic block in the northwest. The mountain first erupted at least 40,000 years ago and has remained active for the most of that time period. There are nine distinct eruptive cycles that have been identified, with durations ranging from 100 years to 5,000 years. Between each of these great periods, there were periods of dormancy. Spirit Lake was barely 3,500 years old when it was formed, while the mountain’s whole surface is less than 2,200 years old.

  1. Several small eruptions were reported as early as 1898, again in 1903, and again in 1921, but the mountain eventually settled down and the locals forgot they were living on a volcano.
  2. An early series of earthquakes and steam explosions produced a crater near the peak and coated the mountain snow with a thick coating of black ash, which is still visible today.
  3. Sliding northward into the Toutle River Valley, the mountain’s whole north face and summit region were wiped off.
  4. Mudslides raced down the North Fork of the Toutle River, submerging homes and highways in the process.
  5. Today, the area is beginning to heal from the destruction, and even the mountain has begun to reestablish herself after her ordeal.

It was late 2004 that a fresh set of lava domes began to emerge within the crater. This current eruption could be a more typical eruption than that of 1980, with rock silently surfacing and collapsing down the sides forming steep rocky slopes as the rock cools.

Human History

The mountain was given the name Louwala-Clough by the Native Americans, which translates to “Smoking Mountain” in the English language. The name St. Helens, like Baker, Rainier, and Hood, was given to the mountain range by Captain Vancouver in 1792. Instead of a British naval commander, the mountain was named after Alleyne Fitzherbert, also known as Baron St. Helens, who was a personal friend of the founder of the United States Navy.

Climbing information

Mount St. Helens is accessible for climbing, although the core of the crater is still off limits to climbers for safety reasons. Even while the climb is a physical challenge, it takes no particular skills or equipment beyond decent boots, warm clothes, eyewear, and water to complete successfully. Permits are necessary to climb the peak, and the number of hikers allowed on the summit each day is limited to 100. Reservations for Mount St. Helens Institute permits can be made online at the institute’s website.

Hiking notes

Mount St. Helens does not have a commanding or inspirational presence in the landscape like the other great volcanoes in the Northwest. Its summit is too low to support year-round snow, and the mountain is too young to have the glacier-carved crags that distinguish mountains such asMount Hood andMountain Rainier from one another. Despite this, Mount St. Helens is an important part of the hiking landscape of the Pacific Northwest. When the volcano erupted in 1980, it created a unique ecosystem, which was notably evident on the mountain’s northern flank.

The Loowit Trail encircle the mountain, weaving in and out of sections that have been damaged for millennia and parts that have been devastated only a few decades.

Photo Gallery

See the Mount Saint Helens picture gallery for more information.

More Links

  • This page contains links to other resources, including the Mount Saint Helens National Monument, the Volcano Cam, Mount Saint Helens eruptive history from Volcano.edu, the Mount Saint Helens Institute, and a map of the surrounding area.


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.

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. The lava dome survived until 1980, when it was completely demolished in a single explosion.

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.

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The debris avalanche and mudflows destroyed the volcano’s top and bulge and flowed down the North Fork of the Toutle River.

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.

It is believed that four billion board feet of timber were lost as a result of the fire. 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.

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

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. The Forest Service planted approximately ten million trees to reforest thousands of acres of land, with the majority of them prospering.

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 additional blasts occurred, resulting in the formation of a new lava dome that stood over 820 feet tall and measured 3,600 feet in diameter 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.


The Smithsonian Institution’s National Museum of Natural History is located in Washington, DC.

Time Machine Tuesday: The Mount St. Helens Eruption

The eruption on May 18, 1980, as captured by the USGS. This spring commemorates the 40th anniversary of the eruption of Mount St. Helens, which culminated in a catastrophic explosion on May 18, 1980. The eruption was the most destructive in recorded history. Mount St. Helens, located in the state of Washington, had previously undergone a few small eruptions in the early 1800s, but had been largely calm since 1857, when the eruption began. Then, in March of 1980, a series of earthquakes began to occur, and experts began to realize that something was wrong.

  1. It was on March 27 that the volcano’s first phreatic (steam) eruption occurred, and minor eruptions persisted intermittently for the following month and a half.
  2. Nothing seems to have changed significantly from the preceding days and weeks.
  3. In the aftermath of the landslide, pressure fluctuations in the magma and volcanic gas generated an enormous lateral blast that erupted only a few seconds later.
  4. Strong winds swept an estimated 540 million tons of volcanic ash hundreds of miles, reaching as far away as Colorado and New Mexico.
  5. The ash cloud emitted by Mount St.
  6. Because the May 18 eruption came as a complete surprise, there were still a large number of people in the immediate proximity of the volcano, despite the fact that Washington had declared a disaster emergency in April and that many people had already left.
  7. Mudslides, forest fires, and other responses were triggered by the eruption.

Communities were having trouble obtaining help since transportation had been cut off in several areas.

Over the next six months, a few minor eruptions were seen, and over the years, periods of activity at the still-active volcano have been documented.

The eruption of Mount St.

What is Colorado’s link to Mount St.

Following the tragedy, the Natural Hazards Research and Applications Information Center at the University of Colorado (now known simply as the Natural Hazards Center) produced a number of papers on the eruption.

Helens, which looked at how local government emergency operations responded to ash fallout near the volcano; and Emergency Response to Mount St.

These studies are accessible for download from our library’s website, and another book, Four Communities Under Ash After Mount St. Helens, is available for loan in print from the same location. Sources:

Mount St Helens Eruption Videos

Scientists from the United States Geological Survey who were engaged in the response to the 1980 eruption of Mount St. Helens narrate their experiences, explain the enormity of the explosion, and share what they learned about volcanoes. Video courtesy of the USGS.

Mount St. Helens Background

In the western part of the Cascade Mountain Range in southern Washington, there is a stratovolcano known as Mount St. Helens, which erupted in 1980. Portland, Oregon is approximately 100 miles south of Seattle and 50 miles northeast of the city of Vancouver, Washington. It is an eruptivevolcanic cone composed of layers of ash, pumice, lava flows, volcanic domes, and other deposits that have been interlayered. It is a very new volcano. The initial eruptions took place around 40,000 years ago, and the volcano evolved through a succession of eruptive phases.

Helens describe their experiences, explain the impact of the explosion, its scale, and what they learned about volcanoes.

Modern Eruptions

The most recent eruption sequence of Mount St. Helens began on May 18, 1980, at 8:32 a.m., and ended on May 18, 1980, at 8:32 a.m. The consequences of this eruption were disastrous. The eruption has been the deadliest and most expensive volcanic eruption in the history of the United States, according to current estimates. Cinqty-seven individuals were killed, and pyroclastic flows, explosion debris, ash, and lahars blanketed hundreds of square kilometers of the landscape. Mount St. Helens: A Change-Inspiring Catalyst Video courtesy of the USGS.

The Opportunity for Monitoring

There were several further eruptions that followed, and these eruptions were utilized by researchers to learn more about monitoring volcanoes, test equipment, and develop monitoring procedures as a result of their findings. In the films on this page, researchers from the United States Geological Survey describe what they learned from the eruptions and what their new information implies for future volcano monitoring efforts in the United States. Mount St. Helens: A Change-Inspiring Catalyst Video courtesy of the USGS.

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Mount St. Helens

Historically, Mount St. Helens has been the most active volcano in the Cascade range, erupting four times in explosive fashion since 1479 and hundreds of lesser eruptions, including pyroclastic flows, lava flows and domes, and lahars, since that time. It is roughly 80 kilometers northeast of Portland, Oregon. Known for its huge explosive eruption, summit collapse, and directed blast on May 18, 1980, which was the most expensive and fatal volcanic event in United States history, Mount St. Helens is the most active volcano in the world.

Mount St.

Both of the most recent eruptions were accompanied by tremors and millions of minor earthquakes. Since the beginning of 2008, there have been no eruptions, and the lava dome has diminished in height as the steep slopes of the volcano erode into a broader, more symmetrical shape.


Spectrograms for Mount St. Helens may be accessed quickly using this shortcut. The magnitude of earthquakes at Mount St. Helens varies greatly depending on the volcano’s eruptive status. A shallow depth under the volcano is the location of most earthquakes; however, a Seismic Zone (SHZ) that stretches north and south of the volcano, and on which some earthquakes take place, is located at a deeper depth beneath the volcano. Just before eruptions commence, seismicity undergoes a shift in nature.

Such changes were detected and recognized as precursors to most of the two dozen or so eruptions that have occurred over the past 30+ years, including a two-month precursory sequence that occurred before the cataclysmic eruption on May 18, 1980, which was the most destructive eruption in recorded history.

  • Helens on average (not including earthquakes that occur during eruptions or their precursors).
  • The depth of earthquakes is much greater during volcanic eruptions and eruption precursor periods.
  • As a result of magma recharge into the main crustal magma system, we believe that these occurrences are the result of stresses caused by the magma.
  • NOTE: The volcano has a depth of 0.0 (zero) km, which means that events occurring within the volcano will plot above sea level (negative depths).
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Recent Seismicity (2016 – present)

Since 2016, earthquakes that have occurred immediately under Mount St. Helens have been plotted against time. This plot is updated once each week. In the event that unexpected activity occurs that signals a different time sequence is required to properly interpret that activity, of course, that time sequence will be followed. Keep in mind that the PNSN earthquake recording and processing system underwent significant changes beginning in 2012, and as a result, there may be minor biases or changes made in the detection, location, and size of seismic events.

Here is a seismicity map that displays the number of earthquakes that have been detected each day (black spikes) as well as the total number of earthquakes that have been detected throughout time (red).

However, sometimes this is due to the fact that greater effort is put in to locate extremely small occurrences, as was the case, at least in part, during the summer of 2014 when the iMUSH experiment was being placed in the region surrounding Mount St.

Here is a map depicting the epicenters of the Mount St.

Helens eruptions from the previous year, color coded by depth and with symbol sizes proportionate to magnitude. The majority of the occurrences are shallow and take place within the crater. Please keep in mind that the black circles signify incidents involving the sea level (negative depths).

Past Seismicity (1980 – 2020)

The time-depth and seismicity plots for Mount St. Helens are presented below, organized by decade, with the most recent data first and moving back in time. In addition to displaying the average or background levels of tremors underneath the volcano, these images also depict the high activity associated with eruptions and magma recharging. We have chosen not to include epicenter maps in this section because, at the regular scale at which they are created, they do not reveal anything of relevance.

Inaccuracies in defining the precise locations are to blame for a large portion of this variability.

It is believed that since the spring of 1980 there has been a sufficient number of seismograph stations positioned on (8) or very close (11) the volcano, allowing the regional seismic network to consistently identify and localize earthquakes of magnitude 0.0 and more in this area.

Time-depth and seismicity counts for 2010 – 2020

No volcanic activity occurred at Mount St. Helens throughout the decade 2010-2020; nonetheless, there were many episodes of enhanced seismic activity, notably in the depth range of 0 – 5 kilometers below sea level. We believe that these times of somewhat increased seismic activity are related to the replinishment of magma into the crustal resevoir under the volcano, which has resulted in a modest rise in pressure. Back in the 1990s, there were moments that were comparable but more dramatic.

Time-depth and Seismicity for 2000 – 2010

From September 2004 to January 2008, the volcano was engaged in a moderate, continuous dome-building eruption (the green bar indicates the time span of the eruption), which resulted in over a million earthquakes, considerably more than could be detected by conventional methods. A sub-sample of events was evaluated and located, and the results are depicted in the figures below. Following the eruption’s cessation (in January 2008), the seismicity returned to normal background levels, and since then, all observed events have been studied and are depicted in the accompanying illustrations.

Time-depth and Seismicity for 1990 – 2000

There were no eruptions of Mount St. Helens during this decade, but, there were times during which seismicity in the depth range of 0 to 6 km depth is regarded as owing to magma recharge into a crustal magma zone. Such recharging might be somewhat continuous, with times of higher flow or pressure, or it can be really episodic, with periods of increased flow or pressure. We have shown on the time-depth map with orange bars the periods during which we believe recharging is taking place as a result of our interpretation.

Time-depth and Seismicity for 1980 -1990

Despite the fact that there were no eruptions of Mount St. Helens throughout this decade, there were episodes of seismicity in the depth range of 0 to 6 km depth, which was thought to be due to magma recharge into a crustal magma zone. Such recharging might be somewhat continuous, with intervals of increasing flow or pressure, or it can be really episodic, with periods of decreased flow or pressure.

We have shown on the time-depth map with orange bars the periods during which we believe recharging is taking place as a result of our assumptions.

Mount St. Helens Fact Sheet

  1. It is located in the Gifford Pinchot National Forest in the state of Washington, approximately 50 miles from Portland, Oregon.
  1. The summit elevation is approximately 8,300 feet at this time. The original elevation before the eruption was 9,677 feet.

The most recent occurrence:

  1. The most recent occurrence was on January 15, 2019.

Other Volcanoes That Are Active:

  1. The first volcanic eruption in the contiguous 48 states since Lassen Peak in California erupted for the last time between 1914 and 1917



  1. From March 27 to May 17, 1980, the main source of activity was steam and ash, with occasional minor mudflows. The eruption of Mount St. Helens began on May 18, when an earthquake produced a massive landslide that completely demolished the mountain’s northern slope. Thousands of trees and plants were destroyed or died as a result of the explosion, which was accompanied by hot gasses, pumice, and ash. The blast damaged more than 150 square miles in a large area north of the mountain, with all trees and flora flattened or dead. The highest ash cloud reached a height of at least 70,000 feet and was tracked all around the world, including Antarctica. A heavy amount of ash fell, causing severe damage to cities as far away as Yakima (85 miles), Spokane (255 miles), Pullman (260 miles), Moscow (260 miles), and Ritzville (195 miles). Yakima received 5/8 inch of ash, while Spokane received 1/8 inch, and Pullman/Moscow received 1/5 inch, and Ritzville (195 miles) received 2 inches. It is estimated that the eruptions on May 25, June 12, and October 16 produced between 1/8 and 1/2 inch of ash in Vancouver, southwestern Washington, and Portland, Oregon. The eruptions on May 25, June 12, and October 16 were accompanied by minor pyroclastic flows. A dome of crusty volcanic lava was detected for the first time following the eruption on June 12. This dome was completely destroyed by the eruption on July 22nd. A second dome, which had been detected on August 8, was destroyed by the October 16 eruption, and a third dome, which had been observed on October 18, was observed developing. From December 27, 1980 to January 4, 1981, a non-explosive event occurred, which resulted in the addition of two more lobes to the October dome. On February 5, April 10, June 18, September 6, and October 30, 1981, non-explosive eruptions added fresh extrusions to the pre-existing composite dome, which had been formed by previous eruptions. Following a period of modest explosive activity accompanied by mudflows, the following eruption began on March 19, 1982, with the extrusion of two more lobes of lava on the dome and a series of tiny explosive events. The eruption continued for another two weeks. Two non-explosive occurrences, on May 14 and August 17, respectively, expanded the existing dome by adding additional lobes. Minor steam plumes and low-level seismic activity are all that can be seen on the mountain, which remains quiet.

36 people died as a result of the accident. People Who Have Gone Missing: 21Crater:

  1. The eruption on May 18 created a crater that was roughly 1 mile wide and 2 miles long. In total, an estimated 1 cubic mile of rock was removed from the mountain, accounting for 12 percent of its total volume. The mountain’s elevation was dropped by roughly 1,370 feet, from 9,677 to 8,307 feet, resulting in a decrease in elevation. Landslides from the crater walls have continued to occur on a regular basis.


  1. Over 2,400 earthquakes of magnitude 2.4 or greater occurred between March 20 and May 18, with 371 of them measuring more than 4.0 on the Richter scale. The strongest signal to date was a 5.1 on May 18. Earthquakes have decreased in frequency significantly since May 19, but their intensity varies depending on the level of eruptive activity.
  1. Massive floods and mudflows caused considerable damage downstream from the disaster region.

Resource Depletion:

  1. As a result of the May 18, 1980 eruption, more than 61,200 acres of National Forest land as well as 89,400 acres held by the state of Washington, private entities, and private persons were badly destroyed. 1.6 billion board feet of wood, 100 miles of streams, 2,300 big game species, 27 recreation areas, 63 miles of road, 13 bridges, 197 miles of trails, and 15 Forest Service facilities are among the National Forest resources that have been damaged or destroyed. The estimated loss of natural resources on National Forest areas is $134,087,000.

Potential dangers include:

  1. Volcanic ash and steam outbursts are a possibility. mudslides (melting snow and ice mixed with ash) that move at breakneck speed
  2. Pyroclastic flows, which are massive volumes of flaming gasses and light-weight volcanic particles that skim over and above the ground at speeds of up to 100 miles per hour, are also known as avalanches. As a result of a large eruption, ashfall is transported by the prevailing winds
  3. Flooding

Chronology of Events

The first earthquake of magnitude 4 was registered on March 20, 1980. During the next week, the number of earthquakes progressively rose, indicating the possibility of imminent volcanic activity. The first explosion of steam and ash occurred on March 27, 1980. Similar explosions were reported up until around April 22nd. The eruptions of steam and ash commenced on May 7, 1980, and persisted until May 14, 1980. Massive landslides and an accompanying intense explosive eruption, which were followed by mudflows, pyroclastic flows, floods, and large ash deposits, occurred on May 18, 1980.

The eruption on October 16 completely demolished the lava dome.

December 27, 1980, February 5, 1981, April 10, 1981, June 18, 1981, September 6, 1981, and October 30, 1981 are the dates on which the events took place.

The eruptive phase of dome expansion began on March 19, 1982, with modest explosive events and tiny mudflows, which resulted in the addition of two additional lobes to the pre-existing dome.

A series of small (one mild and one no-ash) eruptive episodes between May 14 and August 17 (two weeks each) expanded the composite dome’s northwest and south-southwest sides by forming additional lobes on the northwest and south-southwest side.

The dome measured roughly 2500 feet wide and 800 feet high when it was completed in March 1984.

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