A new report issued by the U.S. Geological Survey has classified 18 volcanoes in the U.S. as “very high threats,” including three in California.The agency said a dozen volcanoes have jumped in threat level since 2005, while 20 others dropped in threat level.This is the first time the assessment has been updated since 2005.Watch the video above for a map of the high-risk volcanoes A new report issued by the U.S. Geological Survey has classified 18 volcanoes in the U.S. as “very high threats,” including three in California. The agency said a dozen volcanoes have jumped in threat level since 2005, while 20 others dropped in threat level. Advertisement This is the first time the assessment has been updated since 2005. Watch the video above for a map of the high-risk volcanoes<doc-sep>California is earthquake country. But the state’s complex geology offer another less known threat. For the record: Lassen Peak: This article says that the 1915 eruption of Lassen Peak was the first volcanic eruption within the boundaries of the present-day contiguous 48 states since the country’s founding, and the last until Mt. St. Helens erupted May 18, 1980. There were eruptions before that, such as the intermittent eruptions at Mt. St. Helens between 1800 and 1857. Three of California’s volcanoes are considered to be a very high threat, along with 15 others nationwide, according to the first update of the federal government’s volcano threat assessment in more than a decade. Mt. Shasta in Siskiyou County, the Lassen Volcanic Center in Shasta County and the Long Valley Caldera that includes the Mammoth Lakes area in Mono County remain in the highest risk category as defined by the U.S. Geological Survey. Advertisement The USGS’ list of the 18 “very high threat volcanoes” remains the same as the last such list updated in 2005. They include two such volcanoes on Hawaii’s Big Island: Kilauea, which underwent a new eruption earlier this year and sent oozing lava to destroy hundreds of homes; and Mauna Loa, considered the largest active volcano on the planet. Four are in Oregon, including such areas as Mt. Hood and Crater Lake, and four in Washington state, including Mt. Rainier and Mt. St. Helens, which underwent a deadly eruption in 1980 and is the most active volcano in the Pacific Northwest. Along the West Coast, explosions and volcanic activity under snow and ice can send hazardous projectiles long distances into populated areas, the USGS said. Five are in Alaska and near populated areas and economic infrastructure, or below busy air traffic corridors, the agency said. (Los Angeles Times) There have been 10 eruptions in California over the last 1,000 years, and in any given year the chance of a major volcanic eruption in the state is about the same as the risk of a major earthquake on the San Andreas fault. Some of California’s most scenic wilderness spots are threatened by volcanic activity. More than 190,000 Californians live within a volcano hazard zone; among them are people who live or work in the Long Valley region, home to Mammoth Lakes, a favorite destination of skiers from Southern California, and areas in the shadow of Mt. Shasta, such as the towns of Mount Shasta and Weed. Those cities are close enough to volcanoes that they may be in harm’s way in the next eruption. Volcanoes in the Lassen, Shasta and Long Valley areas are capable of producing pyroclastic flows or surges when they do erupt — fast-moving flows of hot ash, rock and gas sweeping down the sides of mountains, of the type that killed 57 people when Mt. St. Helens erupted in 1980. How the Mt. St. Helens eruption unfolded caught scientists by surprise. There were signs that magma was moving underneath Mt. St. Helens in the months before the eruption. But instead of from the top, the eruption occurred from the side of the volcano — sending magma pressurized with gas erupting out horizontally instead of vertically. Advertisement Because the initial direction of the pyroclastic flow was aimed horizontally, it traveled much farther on land from the summit than had been anticipated, and killed people who were beyond an evacuation zone. Such pyroclastic flows are so hot they will burn flesh and sear lungs; too much ash can also make it hard to breathe. Those who died generally had been within 15 miles of the volcano. Most higher risk volcanoes are far from California’s largest cities and several produce heat that’s used to generate electricity in what are the world’s most productive geothermal power plants, such as the Salton Buttes, 160 miles southeast of Los Angeles, and the Clear Lake Volcanic Field 85 miles north of San Francisco that powers the Geysers steam field. Those areas are considered to be at the second-highest risk category, as is Medicine Lake volcano in Siskiyou and Modoc counties. But volcanic eruptions could have lasting repercussions that affect all of California. Volcanic ash could bring down jetliners and disrupt hundreds of flights daily passing through Northern California or the Mammoth Mountain area. In 2010, the eruption of Iceland’s Eyjafjallajökull volcano forced the cancellation of 100,000 flights in a week. Volcanic ash, when wet, is conductive and can disrupt high-voltage lines that supply electricity to millions of California homes. Ash could disrupt travel on Interstate 5, the main route between California and Oregon, masking windshields and making roads slippery, even impassable. And it could contaminate water supplies to much of the state; California’s largest reservoirs are close to the Shasta and Lassen volcanoes. Advertisement If there’s any good news, it’s that major volcanic activity is usually accompanied by warning signs, and scientists have become much better at forecasting major events before they happen, enabling authorities to sound warnings to reduce the chance of deaths. California’s volcanoes were more prolific in prehistoric times. About 760,000 years ago, a super eruption occurred at what is now known as the Long Valley Caldera, erupting an astonishing 140 cubic miles of magma, covering much of east-central California in glowing hot ash and blowing ash as far away as present-day Nebraska. The Yellowstone volcanic system in Wyoming underwent its own super eruption 640,000 years ago, sending out 240 cubic miles of magma, dumping ash as far away as California, Louisiana and Iowa. (Mt. St. Helens, by contrast, erupted only 0.05 cubic miles of material.) There is no sign that there is enough magma underneath Yellowstone or Long Valley to cause another super eruption, USGS scientists say. Advertisement About a century ago, Lassen Peak underwent years of volcanic activity. In one of the most significant events about 103 years ago, Lassen Peak created a gigantic mushroom cloud that reached an altitude of 30,000 feet. It could be seen as far away as Eureka and Sacramento and sent volcanic ash up to 280 miles away, reaching Elko, Nev.<doc-sep>There are 18 volcanoes in the U.S. that pose a high threat to human life and livelihood, including Kilauea in Hawaii. There are 161 known active volcanoes in the United States, and 18 of them pose a "very high threat" of death and destruction to Americans living nearby, according to a new volcanic risk report released by the U.S. Geological Survey (USGS). Kilauea volcano, which rained destruction on Hawaii's Big Island this summer and forced the evacuation of some 1,700 people, ranked No. 1 on the list due to its recent eruptive history and proximity to heavily populated areas. Rounding out the top five highest-risk volcanoes were Mount St. Helens and Mount Rainier in Washington, Redoubt volcano in Alaska, and Mount Shasta in California. [History's Most Destructive Volcanoes] The new USGS report, published online Monday (Oct. 22), is an update on a similar report released in 2005. According to the authors, the report's threat rankings are "not a forecast or [an] indication of which volcanoes are most likely to erupt next," but rather an indicator of the "potential severity of impacts" that could result from future eruptions at a given volcano. The higher a volcano landed on the list, the more disastrous an eruption could be to people, cities and U.S. infrastructure. Anticipating which volcanoes around the country will have the most destructive potential should help guide research, monitoring and emergency preparation, the authors wrote. To calculate a threat score for each volcanic region, the report's authors weighed the combined effects of 24 risk factors. These included the type of volcano, its explosive potential, recent activity, the number of people living in the vicinity and the potential disruption to air traffic of an eruption. The resulting scores were then used to separate the volcanoes into five risk categories: very low threat (21 volcanoes), low threat (34), moderate threat (49), high threat (38) and very high threat (18). The complete list of "very high threat" volcanoes includes: 1. Kilauea (Hawaii) 2. Mount St. Helens (Wash.) 3. Mount Rainier (Wash.) 4. Redoubt volcano (Alaska) 5. Mount Shasta (Calif.) 6. Mount Hood (Ore.) 7. Three Sisters (Ore.) 8. Akutan Island (Alaska) 9. Makushin volcano (Alaska) 10. Mount Spur (Alaska) 11. Lassen volcanic center (Calif.) 12. Augustine volcano (Alaska) 13. Newberry volcano (Ore.) 14. Mount Baker (Wash.) 15. Glacier Peak (Wash.) 16. Mauna Loa (Hawaii) 17. Crater Lake (Ore.) 18. Long Valley Caldera (Calif.) That these 18 volcanoes pose particular dangers to the surrounding communities is no news to volcanologists; the exact same group appears at the top of the 2005 USGS report. Several volcanoes were added to the master list based on new information collected since 2005, however, including one new "high risk" volcano (the Salton Buttes lava domes in Southern California). Overall, however, the list of 161 known active sites includes eight fewer volcanoes than the 2005 report. "This report may come as a surprise to many, but not to volcanologists," Janine Krippner, a volcano expert at Concord University in West Virginia not involved in the study, told The Guardian. "The USA is one of the most active countries in the world when it comes to [volcanoes]." According to the new report, there have been 120 volcanic eruptions in the United States since 1980. Originally published on Live Science.<doc-sep>Hide Transcript Show Transcript WEBVTT IT’S A HUGE DRAW OF THE NORTHSTATE. A RECREATIONAL RESOURCE AND MORE . BUT THE U.S. GEOLOGICAL SURVEY LISTS MOUNT SHASTA AT NUMBER 5 ON A LIST OF THE 18 U.S. VOLCANOES THAT ARE A VERY HIGH THREAT. AND THERE ARE TWO MORE IN CALIFORNIA. LASSEN VOLCANIC CENTER AT NUMBER 11 AND LONG VALLEY CALDERA AT 18. MOUNT SHASTA’S HIGH RANKING IS OF PARTICULAR CONCERN SAYS MARGARET MANGAN, SCIENTIST IN CHARGE OF THE CALIFORNIA VOLCANO OBSERVATORY. >> CERTAINLY, MOUNT SHASTA IS A VERY HIGH THREAT VOLCANO THAT WE KEEP OUR FINGER ON THE PULSE. >> ITS HAZARD ZONE COVERS ABOUT 9500 SQUARE MILES. ACCORDING TO MAPPING DONE IN THE LATE 1970'S AND 1980'S, WHICH IS CURRENTLY BEING UPDATED. MANGAN SAYS MORE THAN 100,000 PEOPLE LIVE OR WORK IN THIS HAZARD ZONE. AND AN ESTIMATED 37 MILLION CARS PASS BY ON INTERSTATE 5 EACH YEAR. MANGAN SAYS IMPORTANT WATER RESOURCES ARE ALSO IN THE HAZARD ZONE. >> THE UPPER SACRAMENTO RIVER FEEDS OUT OF MOUNT SHASTA. IT’S WITHIN THE HAZARD ZONE. THE SHASTA LAKE RESERVOIR, WHICH IS A HUGE RESOURCE TO THE BAY DELTA, FEEDING WATER TO SEVERAL MILLION PEOPLE IN THE SAN FRANCISCO AREA, ALL THE WAY DOWN THROUGH THE CENTRAL VALLEY. >> MANGAN SAYS THE CLEAR LAKE VOLCANIC FIELD IS OF CONCERN, TOO. ITS THREAT LEVEL IS HIGH. >> THE CLEARLAKE VOLCANIC FIELD IS ONE OF THE CENTERS THAT WE HAVE ONLY RECENTLY REALIZED ITS POTENTIAL THREAT. >> SHE SAYS RESEARCH HAS SHOWN MORE MONITORING IS NEEDED AND 3 SEISMOMETERS WILL BE ADDED IN THE AREA IN THE NEXT TWO Y Advertisement USGS: 3 'very high threat' volcanoes located in California Government ranks 18 US volcanoes in new report Share Shares Copy Link Copy Government scientists have classified 18 U.S. volcanoes as "very high threat" because of what's been happening inside them and how close they are to people.The U.S. Geological Survey has updated its volcano threat assessments for the first time since 2005. The danger list is topped by Hawaii's Kilauea , which has been erupting this year. The others in the top five are Mount St. Helens and Mount Rainier in Washington, Alaska's Redoubt Volcano and California's Mount Shasta . "This report may come as a surprise to many, but not to volcanologists," said Concord University volcano expert Janine Krippner. "The USA is one of the most active countries in the world when it comes to volcanic activity," she said, noting there have been 120 eruptions in U.S. volcanoes since 1980.Kilauea is the most active volcano in the United States "and it's got a lot of development right on its flanks," said government volcanologist John Ewert, the report's chief author. He said Hilo, Hawaii, is probably the biggest city in the United States in a hazard area for a very high threat volcano, Mauna Loa.Ewert said the threat rankings aren't about what will blow next, but "the potential severity" of the damage.Eleven of the 18 very high threat volcanoes are in Oregon, Washington and California.Of the highest threat volcanoes, Washington's Mount Rainier "has the highest number of people in the downstream hazard zone," about 300,000 people, said USGS geologist Angie Diefenbach, a report co-author.Flagstaff, Arizona, is on the border of the large San Francisco Volcanic Field, which is in the moderate threat level, Ewert said.Government scientists use two dozen factors to compute an overall threat score for each of the 161 young active volcanoes in the nation. The score is based on the type of volcano, how explosive it can be, how recently it has been active, how frequently it erupts, if there has been seismic activity, how many people live nearby, if evacuations have happened in the past and if eruptions disrupt air traffic.They are then sorted into five threat levels, ranging from very low to very high.Denison University volcanologist Erik Klemetti said the United States is "sorely deficient in monitoring" for many of the so-called Big 18. "Many of the volcanoes in the Cascades of Oregon and Washington have few, if any, direct monitoring beyond one or two seismometers," Klemetti said in an email. "Once you move down into the high and moderate threat (volcanoes), it gets even dicier. "Because of past activity, Alaska volcanoes tend to have a more extensive monitoring system, said Tom Murray, USGS's volcano science center director.The USGS said a dozen volcanoes have jumped in threat level since 2005. Twenty others dropped in threat level. That includes Salton Buttes, California and Fourpeaked in Alaska. None of the Big 18 changed in overall threat levels, even though 11 had overall threat scores dropping.Threat scores - and levels - change because of better information about the volcanoes, Klemetti said.Among those where the threat score - but not the threat level - is higher are Alaska's Redoubt, Mount Okmok, Akutan Island and Mount Spurr. Threat scores also rose for Oregon's Newberry Volcano and Wyoming's Yellowstone.Besides the top 5, the rest of the Big 18 are: Mount Hood, Three Sisters and Crater Lake in Oregon; Akutan Island, Makushin, Mount Spurr and Augustine in Alaska; Lassen and Long Valley in California; Mount Baker and Glacier Peak in Washington; and Mauna Loa in Hawaii.There's been a lot of speculation of a super eruption at Yellowstone, but Mike Poland, scientist in charge of the Yellowstone Volcano Observatory, said "We don't really have any indication that Yellowstone is doing anything abnormal." ---Story by Associated writer Press Seth Borenstein<doc-sep>
SAN FRANCISCO (CBS SF/AP) — Northern California’s Mount Shasta was included in the top five Thursday on a list of 18 U.S. volcanoes classified as having “very high threat” by the U.S. Geological Survey. The federal scientists said the 18 have been listed because of what’s been happening inside them and how close they are to people. It was the USGS’ first updating of volcano threats in the United States since 2005. The danger list is topped by Hawaii’s Kilauea, which has been erupting this year. The others in the top five are Mount St. Helens and Mount Rainier in Washington, Alaska’s Redoubt Volcano and Mount Shasta. The agency said a dozen volcanoes have jumped in threat level since 2005. Twenty others dropped in threat level. Among those where the threat score is higher are Alaska’s Redoubt, Mount Okmok, Akutan Island and Mount Spurr. Threat scores also rose for Oregon’s Newberry Volcano and Wyoming’s Yellowstone. At an elevation of 14,179 feet, Mount Shasta is the second-highest peak in the Cascades and the fifth-highest in the state. Scientists say Shasta has erupted an average of every 600 years. The last significant eruption may have occurred about two centuries ago. “This report may come as a surprise to many, but not to volcanologists,” said Concord University volcano expert Janine Krippner. “The USA is one of the most active countries in the world when it comes to volcanic activity,” she said, noting there have been 120 eruptions in U.S. volcanoes since 1980. Kilauea is the most active volcano in the United States “and it’s got a lot of development right on its flanks,” said government volcanologist John Ewert, the report’s chief author. He said Hilo, Hawaii, is probably the biggest city in the United States in a hazard area for a very high threat volcano, Mauna Loa. Ewert said the threat rankings aren’t about what will blow next, but “the potential severity” of the damage. Eleven of the 18 very high threat volcanoes are in Oregon, Washington and California. Of the highest threat volcanoes, Washington’s Mount Rainier “has the highest number of people in the downstream hazard zone,” about 300,000 people, said USGS geologist Angie Diefenbach, a report co-author. Flagstaff is on the border of the large San Francisco Volcanic Field, which is in the moderate threat level, Ewert said. Government scientists use two dozen factors to compute an overall threat score for each of the 161 young active volcanoes in the nation. The score is based on the type of volcano, how explosive it can be, how recently it has been active, how frequently it erupts, if there has been seismic activity, how many people live nearby, if evacuations have happened in the past and if eruptions disrupt air traffic. They are then sorted into five threat levels, ranging from very low to very high. Denison University volcanologist Erik Klemetti said the United States is “sorely deficient in monitoring” for many of the so-called Big 18. “Many of the volcanoes in the Cascades of Oregon and Washington have few, if any, direct monitoring beyond one or two seismometers,” Klemetti said in an email. “Once you move down into the high and moderate threat (volcanoes), it gets even dicier.” Because of past activity, Alaska volcanoes tend to have a more extensive monitoring system, said Tom Murray, USGS’s volcano science center director. The USGS said a dozen volcanoes have jumped in threat level since 2005. Twenty others dropped in threat level. That includes Salton Buttes, California and Fourpeaked in Alaska. None of the Big 18 changed in overall threat levels, even though 11 had overall threat scores dropping. Threat scores — and levels — change because of better information about the volcanoes, Klemetti said. Among those where the threat score — but not the threat level — is higher are Alaska’s Redoubt, Mount Okmok, Akutan Island and Mount Spurr. Threat scores also rose for Oregon’s Newberry Volcano and Wyoming’s Yellowstone. Besides the top 5, the rest of the Big 18 are: Mount Hood, Three Sisters and Crater Lake in Oregon; Akutan Island, Makushin, Mount Spurr and Augustine in Alaska; Lassen and Long Valley in California; Mount Baker and Glacier Peak in Washington; and Mauna Loa in Hawaii. There’s been a lot of speculation of a super eruption at Yellowstone, but Mike Poland, scientist in charge of the Yellowstone Volcano Observatory, said “We don’t really have any indication that Yellowstone is doing anything abnormal.” © Copyright 2018 CBS Broadcasting Inc. All Rights Reserved.