America is home to 169 volcanoes that extend miles within the ground, waiting to awaken, but experts have classified 18 as the highest threat to the nation.
The sleeping giants are located in Washington, Oregon, California, Hawaii, American Samoa and Alaska, with some experienced explosions in recent years.
The report from the US Geological Survey (USGS) notes that 13 of the volcanoes are located in densely populated and highly developed areas, and the rest sit in places that would disrupt international aviation if they were to erupt.
One specifically is a supervolcano in California, the Long Valley Caldera, which has not exploded in 760,000 years but has been hit with swarms of earthquakes recently- experts have said these are ‘precursors for an eruption.’
America is home to 169 volcanoes that extend miles within the ground, waiting to awaken, but experts have classified 18 as the highest threat to the nation. The sleeping giants are located in Washington, Oregon, California, Hawaii and Alaska, with some experienced explosions in recent years
The US is one of the most volcanic countries in the world, containing more than 10 percent of Earth’s active volcanos.
It is also home to three of the world’s 20 supervolcanoes – Yellowstone, Long Valley Caldera and the Valles Caldera.
The survey was released in 2018 but is the most updated risk assessment conducted by USGS and builds on the previous report published in 2005.
Experts are constantly monitoring Wyoming’s Yellowstone Caldera as some believe it is overdue for an eruption.
But, the report listed the supervolcano 21st in the assessment.
The most dangerous is Hawaii’s Kīlauea, which erupted on January 5, 2023, when the USGS raised the alert level due to signs magma was moving below the summit surface, an indication the volcano might erupt.
The volcano has frequent eruptions that are usually nonexplosive, but Kīlauea had 50 explosive events in May 1924 during a two-and-a-half-week period and spewed ash and 10-ton rocks into the sky, leaving one man dead.
The most dangerous is Hawaii’s Kīlauea, which erupted on January 5, 2023 (pictured). Kīlauea had 50 explosive events in May 1924 during a two-and-a-half-week period
Mount St Helens in Washington ranked second, but its magma is inherently more explosive than the Kīlauea magma
An eruption in 2018 destroyed more than 700 homes and caused hundreds of millions of dollars in damage.
Mount St Helens in Washington ranked second, but its magma is inherently more explosive than the Kīlauea magma.
This is because the Washington State volcano has more water swirling around inside, which provides more pressure to release the magma.
Mount St Helens released its fury on May 18, 1980, one month after scientists noticed ‘great amounts of ground shaking and avalanching caused by local earthquakes.’
At least 57 people were killed, 230 square miles of land were destroyed, 200 homes were demolished, and miles and miles of highways were ruined – accounting for more than $1 billion in damages.
Also on the list are Washington’s Mount Rainer (last erupted in 1894), Mount Baker (last erupted in 1843) and Glacier Peak (last erupted in 1700).
Also on the list are Washington’s Mount Rainer (last erupted in 1894), Mount Baker (last erupted in 1843) and Glacier Peak (last erupted in 1700). Mount Rainier (pictured) has produced at least four eruptions and numerous lahars in the past 4,000 years
Alaska’s Redoubt Volcano erupted on March 22, 2009, when it sent ash plumes nine miles into the sky. This disaster forced a pause of national and international flights
Mount Rainier in Pierce County, located in the Seattle metropolitan area, has produced at least four eruptions and numerous lahars in the past 4,000 years.
Alaska’s Redoubt Volcano ranked fourth in the assessment, which is an active stratovolcano in the largely volcanic Aleutian Range
It last erupted on March 22, 2009, when it sent plumes of ash nine miles into the sky, forcing air travel to stop – this is a major aviation route for national and international flights.
Data collected 40 to 50 earthquakes were striking every hour.
Before this disaster, Redoubt Volcano exploded over four months from 1989 to 1990.
USGS also determined Alaska’s Akutan Island, Makushin Volcano, Mount Spurr and Augustine Volcano are ‘very high threat’ volcanoes.
Mount Shasta, California was listed as number five in the assessment, which has not pushed magma to the surface in 3,200 years
The state has over 130 volcanoes, with 54 considered historically active – they have exploded in the last 300 years.
Mount Shasta, California was listed as number five in the assessment, which has not pushed magma to the surface in 3,200 years.
‘Mount Shasta erupts episodically with ten or more eruptions occurring in short (500-2,000 year) time periods separated by long intervals (3,000-5,000 years) with few or no eruptions,’ according to the USGS.
Scientists have said that Mount Shasta has erupted an average of every 600 years, with the last significant eruption occurring in 1786.
Scientists at Tuft University assessed the potential hazards that would occur if Mount Shasta blew.
‘Four towns will be destroyed when Mount Shasta erupts: Dunsmuir, McCloud, Mount Shasta, and Weed. Weed will be the town most significantly affected by lahar flooding, losing over 43 percent of its total urban area, followed by McCloud, which will lose 42 percent,’ reads the study.
‘In total, 9112 people will need to be evacuated from these urban areas.’
The four locations would also be buried in over 4,000 feet of ash.
USGS’s 2018 survey also listed California’s Lassen volcanic center, which had 150 explosions in 1915, and the state’s supervolcano, Long Valley Caldera.
Long Valley Caldera erupted about 700,000 years ago, forming the caldera and producing pyroclastic flows that traveled 40 miles from the vent and covered about 932 miles.
California’s Long Valley Caldera has not exploded in 760,000 years but has been hit with swarms of earthquakes recently – experts have said these are ‘precursors for an eruption’
Scientists detected three earthquakes south of the caldera and one beneath the structure in May 1980, marking the beginning of an unrest that continued into the 1990s.
And swarms of earthquakes have plagued Long Valley since.
Scientists at the California Institute of Technology (Caltech) published a study this week about Long Valley’s seismic activity, revealing that more than 2,000quakes have rumbled through the area in recent years.
While swarms are precursors for an eruption, the team found the recent seismic activity results from fluids and gases released as the area cools off and settles down.
However, other scientists like Rob Nelson warn the caldera is gearing up to explode.
‘There are worrying signals of probable volcanic activity,’ Nelson said in Science Channel’s ‘Secrets of the Underground’ documentary.
‘And hints are pointing to an impending eruption strewn over this valley – the location of North America’s second-largest explosive volcanic eruption.’
Experts at the USGS recently determined that 240 cubic miles of magma are sitting beneath a California volcano.
If all the magma were to erupt at once, it would release 800 times the volume of materials than Mount St Helen.
Oregon’s Mount Hood was ranked sixth, which last erupted in 1866, due to sitting close to rapidly growing communities and recreation areas.
The USGS shows that the odds of an eruption in the next 30 years are between three and seven percent.
‘A significant eruption of Mount Hood, such as an eruption of lava domes that collapse to form pyroclastic flows and lahars, would displace several thousand residents and cause billion-dollar-scale damage to infrastructure and buildings,’ the agency shared.
Oregon’s Three Sisters, Newberry Volcano and Crater Lake volcanoes are also high threats.
Along with Hawaii’s Kīlauea, the state’s Mauna Loa volcano is also mentioned in the assessment – ranked 16th.
Mauna Loa is the world’s largest volcano on the south-central part of the main island. The formation last erupted on November 27, 2022 and ended on December 13. Pictured is the volcano erupting on December 3
Mauna Loa is the world’s largest volcano on the south-central part of the main island.
The formation last erupted on November 27, 2022 and ended on December 13.
This was the first eruption since 1984, which lasted for two days and produced lava flows that reached within about four miles of Hilo, a city that’s home to about 44,000 people today.
The USGS assessment is based on 15 hazard factors, including the type of volcano, the known frequency of eruptions, the threat of triggering a tsunami, and the potential for volcanic mudslides or lahars.
The rankings also consider nine so-called exposure factors related to the threats to local communities, such as past fatalities and nearby population density.
Each volcano gets rankings for these factors contributing to its final overall hazard score.
The final list is divided into five categories based on the threat level: very high, high, moderate, low and very low.
‘The threat ranking is not an indication of which volcano will erupt next,’ according to the USGS report.
‘Rather, it indicates how severe the impacts might be from future eruptions at any given volcano.’