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St. Helens, Shasta united by 'ring of fire'
Published October 1, 2004
Combined wire, local reports
Florida has its hurricanes. The Midwest has its tornadoes. And the Pacific Northwest has its volcanoes.
From Mounts Baker and Rainier in Washington to Lassen Peak and Mount Shasta in Northern California - with a seething Mount St. Helens in the middle - the volcanoes of the Cascade Range forms a link in the "ring of fire" that encircles the Pacific Ocean.
The ring runs from the tip of South America up through Alaska, Japan and the Kamchatka Peninsula of Russia, down through the Philippines and Indonesia into New Zealand.
The entire ring includes about three-fourths of the world's active and dormant volcanoes, scientists say.
There are plenty of volcanoes scattered around the rest of the world, including the famed Mount Vesuvius in Italy and Mount Ararat in Turkey. Isolated island chains also produce volcanoes, such as Hawaii and Iceland.
But the ring of fire has been a steady performer that has produced some spectacular blasts in recent history, including the May 1980 eruption of Mount St. Helens that blew the top 1,400 feet off the volcano.
There are occasional rumblings in other Northwest volcanoes.
In the Klamath Basin, Mount Shasta is a enduring visual reminder that the earth's crust is lively and subject to radical alterations.
Geologists believe the 14,161-foot mountain has erupted every 600 to 800 years for the past 10,000 years. Its most recent eruption may have been in 1786, when the French explorer Comte de La Pérouse in 1786 recorded a sighting of an eruption along the northern California coast.
Lassen Peak had a series of eruptions, including explosions and lava flows, from 1914 through 1917.
Other volcanoes in the region include the extinct cone Mount McLouglin, and Southern Oregon's famous Mount Mazama, which exploded about 7,000 years ago to form Crater Lake.
Mount Thielsen is the next in line to the north, followed by Mount Bailey, Diamond Peak and Lava Butte near Bend.
Earthquakes periodically shake Mount Hood - which is Oregon's tallest peak and about 50 miles east of Portland.
Last August, clusters of earthquakes rumbled beneath Alaska's Mount Spurr, which is geologically similar to Mount St. Helens.
Most of the activity is related to shifting in the vast sections of the Earth's surface known as tectonic plates, continent-size chunks of crust that float atop the planet's molten core.
Mount St. Helens and the Cascades lie near the edge of the Juan de Fuca plate, which is diving under the North American plate to create a 700-mile long ''subduction zone'' along the ocean floor that triggers earthquakes and pushes molten rock upwards.
Called magma underground and lava when it erupts on the surface, the molten rock is forced up through fissures and weak spots in the crust, eventually causing eruptions along the volcanic ring.
Mount St. Helens lies along a particularly weak area of the crust, causing it to be the most active volcano in the Northwest over the centuries, said Jon Major, a U.S. Geological Survey researcher in Vancouver, Wash.
''It sits near the St. Helens seismic zone, an area where the crust is pulled apart a little bit,'' Major said. ''That lets magma push up and explains why it's so active and others are not so active.''
Mount Adams, another volcanic peak in the Cascades, lies only about 50 miles east of Mount St. Helens but has not erupted in thousands of years, Major said.
Mount Jefferson, which lies between Mount Hood and the Three Sisters in the Oregon stretch of the Cascades, appears to have been dormant since the last Ice Age despite relatively recent eruptions on neighboring peaks, he said.
Mount Rainier has erupted at least once in the past 200 years. Most were considered minor, according to USGS figures.
The Northwest, in turn, has been relatively quiet compared to other areas of the ring, according to Jim Luhr, director of the global volcanism program at the Smithsonian Institution in Washington, D.C.
The Aleutian Island chain in Alaska, Central America, Japan and Indonesia have all been more active recently, Luhr said.
''The Aleutians are one of the most vigorous volcanic parts of North America,'' he said.
But he noted that other parts of the world have plenty of dormant volcanoes, including France and Germany.
Luhr recently returned from a trip to Armenia where ancient petroglyphs show evidence of eruptions.
''There are relatively young volcanoes all over Armenia,'' he said. ''None have erupted in the last 4,000 years, but clearly ancient peoples have seen them.''
There is a chance that other Northwest volcanoes could erupt. But like Mount St. Helens, it will probably be mostly rock and ash that spew forth, not the dramatic, fiery rivers of lava that accompany eruptions in Hawaii, scientists say.
The Mount St. Helens eruption in 1980 killed 57 people, but other volcanoes have taken a deadlier toll.
In January 2002, lava rolled down the slopes of the African volcano Mount Nyiragongo and flooded the streets of Goma, Congo, killing at least 75 people.
Combined wire, local reports
Florida has its hurricanes. The Midwest has its tornadoes. And the Pacific Northwest has its volcanoes.
From Mounts Baker and Rainier in Washington to Lassen Peak and Mount Shasta in Northern California - with a seething Mount St. Helens in the middle - the volcanoes of the Cascade Range forms a link in the "ring of fire" that encircles the Pacific Ocean.
The ring runs from the tip of South America up through Alaska, Japan and the Kamchatka Peninsula of Russia, down through the Philippines and Indonesia into New Zealand.
The entire ring includes about three-fourths of the world's active and dormant volcanoes, scientists say.
There are plenty of volcanoes scattered around the rest of the world, including the famed Mount Vesuvius in Italy and Mount Ararat in Turkey. Isolated island chains also produce volcanoes, such as Hawaii and Iceland.
But the ring of fire has been a steady performer that has produced some spectacular blasts in recent history, including the May 1980 eruption of Mount St. Helens that blew the top 1,400 feet off the volcano.
There are occasional rumblings in other Northwest volcanoes.
In the Klamath Basin, Mount Shasta is a enduring visual reminder that the earth's crust is lively and subject to radical alterations.
Geologists believe the 14,161-foot mountain has erupted every 600 to 800 years for the past 10,000 years. Its most recent eruption may have been in 1786, when the French explorer Comte de La Pérouse in 1786 recorded a sighting of an eruption along the northern California coast.
Lassen Peak had a series of eruptions, including explosions and lava flows, from 1914 through 1917.
Other volcanoes in the region include the extinct cone Mount McLouglin, and Southern Oregon's famous Mount Mazama, which exploded about 7,000 years ago to form Crater Lake.
Mount Thielsen is the next in line to the north, followed by Mount Bailey, Diamond Peak and Lava Butte near Bend.
Earthquakes periodically shake Mount Hood - which is Oregon's tallest peak and about 50 miles east of Portland.
Last August, clusters of earthquakes rumbled beneath Alaska's Mount Spurr, which is geologically similar to Mount St. Helens.
Most of the activity is related to shifting in the vast sections of the Earth's surface known as tectonic plates, continent-size chunks of crust that float atop the planet's molten core.
Mount St. Helens and the Cascades lie near the edge of the Juan de Fuca plate, which is diving under the North American plate to create a 700-mile long ''subduction zone'' along the ocean floor that triggers earthquakes and pushes molten rock upwards.
Called magma underground and lava when it erupts on the surface, the molten rock is forced up through fissures and weak spots in the crust, eventually causing eruptions along the volcanic ring.
Mount St. Helens lies along a particularly weak area of the crust, causing it to be the most active volcano in the Northwest over the centuries, said Jon Major, a U.S. Geological Survey researcher in Vancouver, Wash.
''It sits near the St. Helens seismic zone, an area where the crust is pulled apart a little bit,'' Major said. ''That lets magma push up and explains why it's so active and others are not so active.''
Mount Adams, another volcanic peak in the Cascades, lies only about 50 miles east of Mount St. Helens but has not erupted in thousands of years, Major said.
Mount Jefferson, which lies between Mount Hood and the Three Sisters in the Oregon stretch of the Cascades, appears to have been dormant since the last Ice Age despite relatively recent eruptions on neighboring peaks, he said.
Mount Rainier has erupted at least once in the past 200 years. Most were considered minor, according to USGS figures.
The Northwest, in turn, has been relatively quiet compared to other areas of the ring, according to Jim Luhr, director of the global volcanism program at the Smithsonian Institution in Washington, D.C.
The Aleutian Island chain in Alaska, Central America, Japan and Indonesia have all been more active recently, Luhr said.
''The Aleutians are one of the most vigorous volcanic parts of North America,'' he said.
But he noted that other parts of the world have plenty of dormant volcanoes, including France and Germany.
Luhr recently returned from a trip to Armenia where ancient petroglyphs show evidence of eruptions.
''There are relatively young volcanoes all over Armenia,'' he said. ''None have erupted in the last 4,000 years, but clearly ancient peoples have seen them.''
There is a chance that other Northwest volcanoes could erupt. But like Mount St. Helens, it will probably be mostly rock and ash that spew forth, not the dramatic, fiery rivers of lava that accompany eruptions in Hawaii, scientists say.
The Mount St. Helens eruption in 1980 killed 57 people, but other volcanoes have taken a deadlier toll.
In January 2002, lava rolled down the slopes of the African volcano Mount Nyiragongo and flooded the streets of Goma, Congo, killing at least 75 people.
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Kaylah wrote on Dec 19, 2007 3:21 PM:
" this was my grandmother, i am one of her many grandchildren and boy oh boy do i miss her. i was looking back throught the herald and news and i am suprised i found this article. it nice to save the news papers every year for some people to pull memories off the web. thank you "
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Sarah Ritch wrote on Jun 18, 2008 10:47 AM:
She made my ribbon dresses and helped to teach me how to fancy dance.
-Sarah Ritch(Garcia) "