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Saturday, May 26, 2018

Mount St. Helens

From Wikipedia, the free encyclopedia
Mount St. Helens
Louwala-Clough
MSH82 st helens plume from harrys ridge 05-19-82.jpg
3,000 ft (1 km) high steam plume on May 19, 1982, two years after its major eruption
Highest point
Elevation 8,363 ft (2,549 m)
Prominence 4,605 ft (1,404 m)
Listing
Coordinates 46°11′28″N 122°11′40″WCoordinates: 46°11′28″N 122°11′40″W[1]
Geography
Mount St. Helens is located in Washington (state)
Mount St. Helens
Mount St. Helens
Parent range Cascade Range
Topo map USGS Mount St. Helens
Geology
Age of rock < 40,000 yrs
Mountain type Active stratovolcano (Subduction zone)
Volcanic arc Cascade Volcanic Arc
Last eruption July 10, 2008
Climbing
First ascent 1853 by Thomas J. Dryer
Easiest route Hike via south slope of volcano (closest area near eruption site)

Mount St. Helens or Louwala-Clough (known as Lawetlat'la to the indigenous Cowlitz people, and Loowit to the Klickitat) is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States. It is 50 miles (80 km) northeast of Portland, Oregon and 96 miles (154 km) south of Seattle, Washington. Mount St. Helens takes its English name from the British diplomat Lord St Helens, a friend of explorer George Vancouver who made a survey of the area in the late 18th century.[1] The volcano is located in the Cascade Range and is part of the Cascade Volcanic Arc, a segment of the Pacific Ring of Fire that includes over 160 active volcanoes. This volcano is well known for its ash explosions and pyroclastic flows.

Mount St. Helens is most notorious for its major 1980 eruption, the deadliest and most economically destructive volcanic event in the history of the United States.[2] Fifty-seven people were killed; 250 homes, 47 bridges, 15 miles (24 km) of railways, and 185 miles (298 km) of highway were destroyed. A massive debris avalanche triggered by an earthquake measuring 5.1 on the Richter scale caused an eruption[3] that reduced the elevation of the mountain's summit from 9,677 ft (2,950 m) to 8,363 ft (2,549 m), leaving a 1 mile (1.6 km) wide horseshoe-shaped crater.[4] The debris avalanche was up to 0.7 cubic miles (2.9 km3) in volume. The Mount St. Helens National Volcanic Monument was created to preserve the volcano and allow for its aftermath to be scientifically studied.

As with most other volcanoes in the Cascade Range, Mount St. Helens is a large eruptive cone consisting of lava rock interlayered with ash, pumice, and other deposits. The mountain includes layers of basalt and andesite through which several domes of dacite lava have erupted. The largest of the dacite domes formed the previous summit, and off its northern flank sat the smaller Goat Rocks dome. Both were destroyed in the 1980 eruption.

Geographic setting and description

General

Landscape with a large open volcano
A view of St. Helens and the nearby area from space
 
A large conical volcano.
Mount St. Helens the day before the 1980 eruption, which removed much of the northern face of the mountain, leaving a large crater
 
3-D perspective view of Mount St. Helens

Mount St. Helens is 34 miles (55 km) west of Mount Adams, in the western part of the Cascade Range. These "sister and brother" volcanic mountains are approximately 50 miles (80 km) from Mount Rainier, the highest of Cascade volcanoes. Mount Hood, the nearest major volcanic peak in Oregon, is 60 miles (100 km) southeast of Mount St. Helens.

Mount St. Helens is geologically young compared with the other major Cascade volcanoes. It formed only within the past 40,000 years, and the pre-1980 summit cone began rising about 2,200 years ago.[5] The volcano is considered the most active in the Cascades within the Holocene epoch (the last 10,000 or so years).[6]

Prior to the 1980 eruption, Mount St. Helens was the fifth-highest peak in Washington. It stood out prominently from surrounding hills because of the symmetry and extensive snow and ice cover of the pre-1980 summit cone, earning it the nickname "Fuji-san of America".[7] The peak rose more than 5,000 feet (1,500 m) above its base, where the lower flanks merge with adjacent ridges. The mountain is 6 miles (9.7 km) across at its base, which is at an elevation of 4,400 feet (1,300 m) on the northeastern side and 4,000 feet (1,200 m) elsewhere. At the pre-eruption tree line, the width of the cone was 4 miles (6.4 km).

View of Mt. St. Helens from a commercial airliner, July 2007

Streams that originate on the volcano enter three main river systems: the Toutle River on the north and northwest, the Kalama River on the west, and the Lewis River on the south and east. The streams are fed by abundant rain and snow. The average annual rainfall is 140 inches (3,600 mm), and the snow pack on the mountain's upper slopes can reach 16 feet (4.9 m).[8] The Lewis River is impounded by three dams for hydroelectric power generation. The southern and eastern sides of the volcano drain into an upstream impoundment, the Swift Reservoir, which is directly south of the volcano's peak.

April 30, 2015 Mount St Helens[9]

Although Mount St. Helens is in Skamania County, Washington, access routes to the mountain run through Cowlitz County to the west. State Route 504, locally known as the Spirit Lake Memorial Highway, connects with Interstate 5 at Exit 49, 34 miles (55 km) to the west of the mountain. That north–south highway skirts the low-lying cities of Castle Rock, Longview and Kelso along the Cowlitz River, and passes through the Vancouver, WashingtonPortland, Oregon metropolitan area less than 50 miles (80 km) to the southwest. The community nearest the volcano is Cougar, Washington, in the Lewis River valley 11 miles (18 km) south-southwest of the peak. Gifford Pinchot National Forest surrounds Mount St. Helens.

Crater Glacier and other new rock glaciers

Summit rim of Mount St. Helens

During the winter of 1980–1981, a new glacier appeared. Now officially named Crater Glacier, it was formerly known as the Tulutson Glacier. Shadowed by the crater walls and fed by heavy snowfall and repeated snow avalanches, it grew rapidly (14 feet (4.3 m) per year in thickness). By 2004, it covered about 0.36 square miles (0.93 km2), and was divided by the dome into a western and eastern lobe. Typically, by late summer, the glacier looks dark from rockfall from the crater walls and ash from eruptions. As of 2006, the ice had an average thickness of 300 feet (100 m) and a maximum of 650 feet (200 m), nearly as deep as the much older and larger Carbon Glacier of Mount Rainier. The ice is all post–1980, making the glacier very young geologically. However, the volume of the new glacier is about the same as all the pre–1980 glaciers combined.[10][11][12][13][14]

With the recent volcanic activity starting in 2004, the glacier lobes were pushed aside and upward by the growth of new volcanic domes. The surface of the glacier, once mostly without crevasses, turned into a chaotic jumble of icefalls heavily criss-crossed with crevasses and seracs caused by movement of the crater floor.[15] The new domes have almost separated the Crater Glacier into an eastern and western lobe. Despite the volcanic activity, the termini of the glacier have still advanced, with a slight advance on the western lobe and a more considerable advance on the more shaded eastern lobe. Due to the advance, two lobes of the glacier joined together in late May 2008 and thus the glacier completely surrounds the lava domes.[15][16][17] In addition, since 2004, new glaciers have formed on the crater wall above Crater Glacier feeding rock and ice onto its surface below; there are two rock glaciers to the north of the eastern lobe of Crater Glacier.[18] Crater Glacier is the only known advancing glacier in the contiguous United States.[19]

Geologic history

Ancestral stages of eruptive activity

Map of the west coast of United States with dark lines in the ocean and location of Cascade Volcanoes.

The early eruptive stages of Mount St. Helens are known as the "Ape Canyon Stage" (around 40,000–35,000 years ago), the "Cougar Stage" (ca. 20,000–18,000 years ago), and the "Swift Creek Stage" (roughly 13,000–8,000 years ago).[20] The modern period, since about 2500 BCE, is called the "Spirit Lake Stage". Collectively, the pre–Spirit Lake stages are known as the "ancestral stages". The ancestral and modern stages differ primarily in the composition of the erupted lavas; ancestral lavas consisted of a characteristic mixture of dacite and andesite, while modern lava is very diverse (ranging from olivine basalt to andesite and dacite).[21]

St. Helens started its growth in the Pleistocene 37,600 years ago, during the Ape Canyon stage, with dacite and andesite eruptions of hot pumice and ash.[21] Thirty-six thousand years ago a large mudflow cascaded down the volcano;[21] mudflows were significant forces in all of St. Helens' eruptive cycles. The Ape Canyon eruptive period ended around 35,000 years ago and was followed by 17,000 years of relative quiet. Parts of this ancestral cone were fragmented and transported by glaciers 14,000 to 18,000 years ago during the last glacial period of the current ice age.[21]

The second eruptive period, the Cougar Stage, started 20,000 years ago and lasted for 2,000 years.[21] Pyroclastic flows of hot pumice and ash along with dome growth occurred during this period. Another 5,000 years of dormancy followed, only to be upset by the beginning of the Swift Creek eruptive period, typified by pyroclastic flows, dome growth and blanketing of the countryside with tephra. Swift Creek ended 8,000 years ago.

Smith Creek and Pine Creek eruptive periods

A dormancy of about 4,000 years was broken around 2500 BCE with the start of the Smith Creek eruptive period, when eruptions of large amounts of ash and yellowish-brown pumice covered thousands of square miles. An eruption in 1900 BCE was the largest known eruption from St. Helens during the Holocene epoch, judged by the volume of one of the tephra layers from that period. This eruptive period lasted until about 1600 BCE and left 18 inches (46 cm) deep deposits of material 50 miles (80 km) distant in what is now Mt. Rainier National Park. Trace deposits have been found as far northeast as Banff National Park in Alberta, and as far southeast as eastern Oregon.[22] All told there may have been up to 2.5 cubic miles (10 km3) of material ejected in this cycle.[22] Some 400 years of dormancy followed.

St. Helens came alive again around 1200 BCE — the Pine Creek eruptive period.[22] This lasted until about 800 BCE and was characterized by smaller-volume eruptions. Numerous dense, nearly red hot pyroclastic flows sped down St. Helens' flanks and came to rest in nearby valleys. A large mudflow partly filled 40 miles (64 km) of the Lewis River valley sometime between 1000 BCE and 500 BCE.

Castle Creek and Sugar Bowl eruptive periods

The next eruptive period, the Castle Creek period, began about 400 BCE, and is characterized by a change in composition of St. Helens' lava, with the addition of olivine and basalt.[23] The pre-1980 summit cone started to form during the Castle Creek period. Significant lava flows in addition to the previously much more common fragmented and pulverized lavas and rocks (tephra) distinguished this period. Large lava flows of andesite and basalt covered parts of the mountain, including one around the year 100 BCE that traveled all the way into the Lewis and Kalama river valleys.[23] Others, such as Cave Basalt (known for its system of lava tubes), flowed up to 9 miles (14 km) from their vents.[23] During the first century, mudflows moved 30 miles (50 km) down the Toutle and Kalama river valleys and may have reached the Columbia River. Another 400 years of dormancy ensued.

The Sugar Bowl eruptive period was short and markedly different from other periods in Mount St. Helens history. It produced the only unequivocal laterally directed blast known from Mount St. Helens before the 1980 eruptions.[24] During Sugar Bowl time, the volcano first erupted quietly to produce a dome, then erupted violently at least twice producing a small volume of tephra, directed-blast deposits, pyroclastic flows, and lahars.[24]

Kalama and Goat Rocks eruptive periods

Painting of a rolling landscape with a conical mountain in background.
The symmetrical appearance of St. Helens prior to the 1980 eruption earned it the nickname "Mount Fuji of America". The once familiar shape was formed out of the Kalama and Goat Rocks eruptive periods.

Roughly 700 years of dormancy were broken in about 1480, when large amounts of pale gray dacite pumice and ash started to erupt, beginning the Kalama period. The eruption in 1480 was several times larger than the May 18, 1980, eruption.[24] In 1482, another large eruption rivaling the 1980 eruption in volume is known to have occurred.[24] Ash and pumice piled 6 miles (9.7 km) northeast of the volcano to a thickness of 3 feet (0.9 m); 50 miles (80 km) away, the ash was 2 inches (5 cm) deep. Large pyroclastic flows and mudflows subsequently rushed down St. Helens' west flanks and into the Kalama River drainage system.

This 150-year period next saw the eruption of less silica-rich lava in the form of andesitic ash that formed at least eight alternating light- and dark-colored layers.[23] Blocky andesite lava then flowed from St. Helens' summit crater down the volcano's southeast flank.[23] Later, pyroclastic flows raced down over the andesite lava and into the Kalama River valley. It ended with the emplacement of a dacite dome several hundred feet (~200 m) high at the volcano's summit, which filled and overtopped an explosion crater already at the summit.[25] Large parts of the dome's sides broke away and mantled parts of the volcano's cone with talus. Lateral explosions excavated a notch in the southeast crater wall. St. Helens reached its greatest height and achieved its highly symmetrical form by the time the Kalama eruptive cycle ended, about 1647.[25] The volcano remained quiet for the next 150 years.

The 57-year eruptive period that started in 1800 was named after the Goat Rocks dome, and is the first time that both oral and written records exist.[25] Like the Kalama period, the Goat Rocks period started with an explosion of dacite tephra, followed by an andesite lava flow, and culminated with the emplacement of a dacite dome. The 1800 eruption probably rivalled the 1980 eruption in size, although it did not result in massive destruction of the cone. The ash drifted northeast over central and eastern Washington, northern Idaho, and western Montana. There were at least a dozen reported small eruptions of ash from 1831 to 1857, including a fairly large one in 1842. The vent was apparently at or near Goat Rocks on the northeast flank.[25] Goat Rocks dome was the site of the bulge in the 1980 eruption, and it was obliterated in the major eruption event on May 18, 1980 that destroyed the entire north face and top 1,300 feet (400 m) of the mountain.

Modern eruptive period

1980 to 2001 activity

This composite photograph of the May 18 eruption was taken from 35 miles (60 km) west in Toledo, Washington. The ash-cloud stem is 10 miles (16 km) wide, and the mushroom top is 40 miles (64 km) wide and 15 miles (24 km) high. The footprint of the cloud stem is roughly the same as the devastated area north of the mountain where the forest was knocked down and which three decades later is still relatively barren.

On March 20, 1980, Mount St. Helens experienced a magnitude 4.2 earthquake;[2] and, on March 27, steam venting started.[26] By the end of April, the north side of the mountain had started to bulge.[27] On May 18, a second earthquake, of magnitude 5.1, triggered a massive collapse of the north face of the mountain. It was the largest known debris avalanche in recorded history. The magma in St. Helens burst forth into a large-scale pyroclastic flow that flattened vegetation and buildings over 230 square miles (600 km2). More than 1.5 million metric tons of sulfur dioxide was released into the atmosphere.[28] On the Volcanic Explosivity Index scale, the eruption was rated a five, and categorized as a Plinian eruption.

Mount St. Helens erupted on May 18, 1980, at 08:32 Pacific Daylight Time

The collapse of the northern flank of St. Helens mixed with ice, snow, and water to create lahars (volcanic mudflows). The lahars flowed many miles down the Toutle and Cowlitz Rivers, destroying bridges and lumber camps. A total of 3,900,000 cubic yards (3,000,000 m3) of material was transported 17 miles (27 km) south into the Columbia River by the mudflows.[29]

For more than nine hours, a vigorous plume of ash erupted, eventually reaching 12 to 16 miles (20 to 27 km) above sea level.[30] The plume moved eastward at an average speed of 60 miles per hour (100 km/h) with ash reaching Idaho by noon. Ashes from the eruption were found collecting on top of cars and roofs next morning, as far as the city of Edmonton in Alberta, Canada.

Diagram with different colored layers.
Lava dome growth profile from 1980–1986

By about 5:30 p.m. on May 18, the vertical ash column declined in stature, and less severe outbursts continued through the night and for the next several days. The St. Helens May 18 eruption released 24 megatons of thermal energy;[3][31] it ejected more than 0.67 cubic miles (2.79 km3) of material.[3] The removal of the north side of the mountain reduced St. Helens' height by about 1,300 feet (400 m) and left a crater 1 mile (1.6 km) to 2 miles (3.2 km) wide and 0.5 miles (800 m) deep, with its north end open in a huge breach. The eruption killed 57 people, nearly 7,000 big game animals (deer, elk, and bear), and an estimated 12 million fish from a hatchery.[8] It destroyed or extensively damaged over 200 homes, 185 miles (298 km) of highway and 15 miles (24 km) of railways.[8]

Between 1980 and 1986, activity continued at Mount St. Helens, with a new lava dome forming in the crater. Numerous small explosions and dome-building eruptions occurred. From December 7, 1989, to January 6, 1990, and from November 5, 1990, to February 14, 1991, the mountain erupted with sometimes huge clouds of ash.[32]

2004 to 2008 activity

Magma reached the surface of the volcano about October 11, 2004, resulting in the building of a new lava dome on the existing dome's south side. This new dome continued to grow throughout 2005 and into 2006. Several transient features were observed, such as a lava spine nicknamed the "whaleback," which comprised long shafts of solidified magma being extruded by the pressure of magma beneath. These features were fragile and broke down soon after they were formed. On July 2, 2005, the tip of the whaleback broke off, causing a rockfall that sent ash and dust several hundred meters into the air.[33]
 
Large fairly smooth rock structure inside a crater
Appearance of the "Whaleback" in February 2005

Mount St. Helens showed significant activity on March 8, 2005, when a 36,000-foot (11,000 m) plume of steam and ash emerged—visible from Seattle.[34] This relatively minor eruption was a release of pressure consistent with ongoing dome building. The release was accompanied by a magnitude 2.5 earthquake.

Another feature to emerge from the dome was called the "fin" or "slab." Approximately half the size of a football field, the large, cooled volcanic rock was being forced upward as quickly as 6 ft (2 m) per day.[35][36] In mid-June 2006, the slab was crumbling in frequent rockfalls, although it was still being extruded. The height of the dome was 7,550 feet (2,300 m), still below the height reached in July 2005 when the whaleback collapsed.

Microscopic view of a rock
Thin section of dacite from a dome created in 2004

On October 22, 2006, at 3:13 p.m. PST, a magnitude 3.5 earthquake broke loose Spine 7. The collapse and avalanche of the lava dome sent an ash plume 2,000 feet (600 m) over the western rim of the crater; the ash plume then rapidly dissipated.

On December 19, 2006, a large white plume of condensing steam was observed, leading some media people to assume there had been a small eruption. However, the Cascades Volcano Observatory of the USGS did not mention any significant ash plume.[37] The volcano was in continuous eruption from October 2004, but this eruption consisted in large part of a gradual extrusion of lava forming a dome in the crater.

On January 16, 2008, steam began seeping from a fracture on top of the lava dome. Associated seismic activity was the most noteworthy since 2004. Scientists suspended activities in the crater and the mountain flanks, but the risk of a major eruption was deemed low.[38] By the end of January, the eruption paused; no more lava was being extruded from the lava dome. On July 10, 2008, it was determined that the eruption had ended, after more than six months of no volcanic activity.[39]

360° panorama from the summit of Mount St. Helens as seen in October 2009. In the foreground is the ice-covered crater rim. Visible in the lower center is the lava dome. Steam rises from several dome vents. Above the dome, in the upper center, lies Mount Rainier and Spirit Lake. Mount Adams appears to the right of Rainier on the horizon as well as Mount Hood and Mount Jefferson on the far right. Also on the far right are glimpses of the Swift Reservoir, Yale Lake, Lake Merwin and the Lewis River. Climbers stand on the crater rim and are visible along the Monitor Ridge climbing route.

Human history

Importance to Native Americans

Mt St Helens before the 1980 eruption (taken from Spirit Lake)
Indigenous American legends were inspired by the volcano's beauty.
American Indian lore contains numerous legends to explain the eruptions of Mount St. Helens and other Cascade volcanoes. The most famous of these is the Bridge of the Gods legend told by the Klickitat people. In their tale, the chief of all the gods and his two sons, Pahto (also called Klickitat) and Wy'east, traveled down the Columbia River from the Far North in search for a suitable area to settle.[40]

They came upon an area that is now called The Dalles and thought they had never seen a land so beautiful. The sons quarreled over the land, so to solve the dispute their father shot two arrows from his mighty bow — one to the north and the other to the south. Pahto followed the arrow to the north and settled there while Wy'east did the same for the arrow to the south. The chief of the gods then built the Bridge of the Gods, so his family could meet periodically.[40]

When the two sons of the chief of the gods fell in love with a beautiful maiden named Loowit, she could not choose between them. The two young chiefs fought over her, burying villages and forests in the process. The area was devastated and the earth shook so violently that the huge bridge fell into the river, creating the cascades of the Columbia River Gorge.[41]

For punishment, the chief of the gods struck down each of the lovers and transformed them into great mountains where they fell. Wy'east, with his head lifted in pride, became the volcano known today as Mount Hood. Pahto, with his head bent toward his fallen love, was turned into Mount Adams. The fair Loowit became Mount St. Helens, known to the Klickitats as Louwala-Clough, which means "smoking or fire mountain" in their language (the Sahaptin called the mountain Loowit).[42]

The mountain is also of sacred importance to the Cowlitz and Yakama tribes that also historically lived in the area. They find the area above its tree line to be of exceptional spiritual significance, and the mountain (which they call "Lawetlat'la", roughly translated as "the smoker") features prominently in their creation myth, and in some of their songs and rituals. In recognition of this cultural significance, over 12,000 acres (4,900 ha) of the mountain (roughly bounded by the Loowit Trail) have been listed on the National Register of Historic Places.[43]

Other area tribal names for the mountain include "nšh´ák´" ("water coming out") from the Upper Chehalis, and "aka akn" ("snow mountain"), a Kiksht term.[43]

Exploration by Europeans

Royal Navy Commander George Vancouver and the officers of HMS Discovery made the Europeans' first recorded sighting of Mount St. Helens on May 19, 1792, while surveying the northern Pacific Ocean coast. Vancouver named the mountain for British diplomat Alleyne Fitzherbert, 1st Baron St Helens on October 20, 1792,[42][44] as it came into view when the Discovery passed into the mouth of the Columbia River.

Years later, explorers, traders, and missionaries heard reports of an erupting volcano in the area. Geologists and historians determined much later that the eruption took place in 1800, marking the beginning of the 57-year-long Goat Rocks Eruptive Period (see geology section).[25] Alarmed by the "dry snow," the Nespelem tribe of northeastern Washington danced and prayed rather than collecting food and suffered during that winter from starvation.[25]

In late 1805 and early 1806, members of the Lewis and Clark Expedition spotted Mount St. Helens from the Columbia River but did not report either an ongoing eruption or recent evidence of one.[45] They did however report the presence of quicksand and clogged channel conditions at the mouth of the Sandy River near Portland, suggesting an eruption by Mount Hood sometime in the previous decades.

In 1829 Hall J. Kelley led a campaign to rename the Cascade Range as the President's Range and also to rename each major Cascade mountain after a former President of the United States. In his scheme Mount St. Helens was to be renamed Mount Washington.[46]

European settlement and use of the area

Man by wooden building that has six fur pelts on it.
19th-century photo of a fur trapper working in the Mount St. Helens area

The first authenticated eyewitness report of a volcanic eruption was made in March 1835 by Meredith Gairdner, while working for the Hudson's Bay Company stationed at Fort Vancouver.[47] He sent an account to the Edinburgh New Philosophical Journal, which published his letter in January 1836. James Dwight Dana of Yale University, while sailing with the United States Exploring Expedition, saw the quiescent peak from off the mouth of the Columbia River in 1841. Another member of the expedition later described "cellular basaltic lavas" at the mountain's base.[48]

Painting of a conical volcano erupting at night from the side.
Painting by Paul Kane Mount St. Helens erupting at night after his 1847 visit to the area

In late fall or early winter of 1842, nearby settlers and missionaries witnessed the so-called "Great Eruption". This small-volume outburst created large ash clouds, and mild explosions followed for 15 years.[49] The eruptions of this period were likely phreatic (steam explosions). Josiah Parrish in Champoeg, Oregon witnessed Mount St. Helens in eruption on November 22, 1842. Ash from this eruption may have reached The Dalles, Oregon, 48 miles (80 km) southeast of the volcano.[6]

In October 1843, future California governor Peter H. Burnett recounted a story of an aboriginal American man who badly burned his foot and leg in lava or hot ash while hunting for deer. The likely apocryphal story went that the injured man sought treatment at Fort Vancouver, but the contemporary fort commissary steward, Napoleon McGilvery, disclaimed knowledge of the incident.[50] British lieutenant Henry J. Warre sketched the eruption in 1845, and two years later Canadian painter Paul Kane created watercolors of the gently smoking mountain. Warre's work showed erupting material from a vent about a third of the way down from the summit on the mountain's west or northwest side (possibly at Goat Rocks), and one of Kane's field sketches shows smoke emanating from about the same location.[51]

On April 17, 1857, the Republican, a Steilacoom, Washington, newspaper, reported that "Mount St. Helens, or some other mount to the southward, is seen ... to be in a state of eruption".[52] The lack of a significant ash layer associated with this event indicates that it was a small eruption. This was the first reported volcanic activity since 1854.[52]

Before the 1980 eruption, Spirit Lake offered year-round recreational activities. In the summer there was boating, swimming, and camping, while in the winter there was skiing.

Human impact from the 1980 eruption

Man sitting at a campsite
David A. Johnston hours before he was killed by the eruption

Fifty-seven people were killed during the eruption.[53] Had the eruption occurred one day later, when loggers would have been at work, rather than on a Sunday, the death toll could have been much higher.[8]

83-year-old Harry R. Truman, who had lived near the mountain for 54 years, became famous when he decided not to evacuate before the impending eruption, despite repeated pleas by local authorities. His body was never found after the eruption.

Another victim of the eruption was 30-year-old volcanologist David A. Johnston, who was stationed on the nearby Coldwater Ridge. Moments before his position was hit by the pyroclastic flow, Johnston radioed his famous last words: "Vancouver! Vancouver! This is it!"[54] Johnston's body was never found.

U.S. President Jimmy Carter surveyed the damage and said, "Someone said this area looked like a moonscape. But the moon looks more like a golf course compared to what's up there."[55] A film crew, led by Seattle filmmaker Otto Seiber, was dropped by helicopter on St. Helens on May 23 to document the destruction. Their compasses, however, spun in circles and they quickly became lost. A second eruption occurred on May 25, but the crew survived and was rescued two days later by National Guard helicopter pilots. Their film, The Eruption of Mount St. Helens, later became a popular documentary.

Protection and later history

View of the hillside at the Johnston Ridge Observatory (named for David A. Johnston), 25 years after the eruption
 
Johnston Ridge from a proximate location in July 2016, showing continued plant growth

In 1982, President Ronald Reagan and the U.S. Congress established the Mount St. Helens National Volcanic Monument, a 110,000 acres (45,000 ha) area around the mountain and within the Gifford Pinchot National Forest.[56]

Following the 1980 eruption, the area was left to gradually return to its natural state. In 1987, the U.S. Forest Service reopened the mountain to climbing. It remained open until 2004 when renewed activity caused the closure of the area around the mountain (see Geological history section above for more details).

Most notable was the closure of the Monitor Ridge trail, which previously let up to 100 permitted hikers per day climb to the summit. On July 21, 2006, the mountain was again opened to climbers.[57] In February 2010, a climber died after falling from the rim into the crater.[58]

The mountain is now circled by the Loowit Trail at elevations of 4000–4900 feet (1,200-1,500 m). The northern segment of the trail from the South Fork Toutle River on the west to Windy Pass on the east is a restricted zone where camping, biking, pets, fires, and off-trail excursions are all prohibited.[59][60]

Climbing and recreation

Mount St. Helens is a popular climbing destination for both beginning and experienced mountaineers. The peak is climbed year-round, although it is more often climbed from late spring through early fall. All routes include sections of steep, rugged terrain.[61] A permit system has been in place for climbers since 1987. A climbing permit is required year-round for anyone who will be above 4,800 feet (1,500 m) on the slopes of Mount St. Helens.[62]

The standard hiking/mountaineering route in the warmer months is the Monitor Ridge Route, which starts at the Climbers Bivouac. This is the most popular and crowded route to the summit in the summer and gains about 4,600 feet (1,400 m) in approximately 5 miles (8 km) to reach the crater rim.[63] Although strenuous, it is considered non-technical climb that involves some scrambling. Most climbers complete the round trip in 7 to 12 hours.[64]

The Worm Flows Route is considered the standard winter route on Mount St. Helens, as it is the most direct route to the summit. The route gains about 5,700 feet (1,700 m) in elevation over about 6 miles (10 km) from trailhead to summit but does not demand the technical climbing that some other Cascade peaks like Mount Rainier do. The "Worm Flows" part of the route name refers to the rocky lava flows that surround the route.[65] This route can be accessed via the Marble Mountain Sno-Park and the Swift Ski Trail.[66]

Friday, May 25, 2018

Wolfgang Pauli

    From Wikipedia, the free encyclopedia
    Wolfgang Ernst Pauli
    Pauli.jpg
    Born Wolfgang Ernst Pauli
    25 April 1900
    Vienna, Austria-Hungary
    Died 15 December 1958 (aged 58)
    Zurich, Switzerland
    Nationality Austria
    Citizenship Austria-Hungary
    Switzerland
    United States
    Alma mater Ludwig-Maximilians University
    Known for
    Awards
    Scientific career
    Fields Theoretical physics
    Institutions University of Göttingen
    University of Copenhagen
    University of Hamburg
    ETH Zurich
    Institute for Advanced Study
    Thesis About the Hydrogen Molecular Ion Model[3] (1921)
    Doctoral advisor Arnold Sommerfeld[3][2]
    Other academic advisors Max Born[citation needed]
    Doctoral students
    Other notable students
    Influences
    Influenced Ralph Kronig[citation needed]
    Notes
    His godfather was Ernst Mach. He is not to be confused with Wolfgang Paul, who called Pauli his "imaginary part",[4] a pun with the imaginary unit i.

    Wolfgang Ernst Pauli (/ˈpɔːli/;[5] German: [ˈpaʊli]; 25 April 1900 – 15 December 1958) was an Austrian-born Swiss and American theoretical physicist and one of the pioneers of quantum physics. In 1945, after having been nominated by Albert Einstein,[6] Pauli received the Nobel Prize in Physics for his "decisive contribution through his discovery of a new law of Nature, the exclusion principle or Pauli principle". The discovery involved spin theory, which is the basis of a theory of the structure of matter.

    Biography

    Early years

    Pauli was born in Vienna to a chemist Wolfgang Joseph Pauli ( Wolf Pascheles, 1869–1955) and his wife Bertha Camilla Schütz; his sister was Hertha Pauli, the writer and actress. Pauli's middle name was given in honor of his godfather, physicist Ernst Mach. Pauli's paternal grandparents were from prominent Jewish families of Prague; his great-grandfather was the Jewish publisher Wolf Pascheles.[7] Pauli's father converted from Judaism to Roman Catholicism shortly before his marriage in 1899. Pauli's mother, Bertha Schütz, was raised in her own mother's Roman Catholic religion; her father was Jewish writer Friedrich Schütz. Pauli was raised as a Roman Catholic, although eventually he and his parents left the Church.[8] He is considered to have been a deist and a mystic.[9][10]

    Pauli attended the Döblinger-Gymnasium in Vienna, graduating with distinction in 1918. Only two months after graduation, he published his first paper, on Albert Einstein's theory of general relativity. He attended the Ludwig-Maximilians University in Munich, working under Arnold Sommerfeld,[2] where he received his PhD in July 1921 for his thesis on the quantum theory of ionized diatomic hydrogen (H+
    2
    ).[3][11]

    Sommerfeld asked Pauli to review the theory of relativity for the Encyklopädie der mathematischen Wissenschaften (Encyclopedia of Mathematical Sciences). Two months after receiving his doctorate, Pauli completed the article, which came to 237 pages. It was praised by Einstein; published as a monograph, it remains a standard reference on the subject to this day.

    Wolfgang Pauli lecturing

    Pauli spent a year at the University of Göttingen as the assistant to Max Born, and the following year at the Institute for Theoretical Physics in Copenhagen, which later became the Niels Bohr Institute in 1965. From 1923 to 1928, he was a lecturer at the University of Hamburg. During this period, Pauli was instrumental in the development of the modern theory of quantum mechanics. In particular, he formulated the exclusion principle and the theory of nonrelativistic spin.

    In 1928, he was appointed Professor of Theoretical Physics at ETH Zurich in Switzerland where he made significant scientific progress. He held visiting professorships at the University of Michigan in 1931, and the Institute for Advanced Study in Princeton in 1935. He was awarded the Lorentz Medal in 1931.

    At the end of 1930, shortly after his postulation of the neutrino and immediately following his divorce and the suicide of his mother, Pauli experienced a personal crisis. He consulted psychiatrist and psychotherapist Carl Jung who, like Pauli, lived near Zurich. Jung immediately began interpreting Pauli's deeply archetypal dreams,[12] and Pauli became one of the depth psychologist's best students. He soon began to criticize the epistemology of Jung's theory scientifically, and this contributed to a certain clarification of the latter's thoughts, especially about the concept of synchronicity. A great many of these discussions are documented in the Pauli/Jung letters, today published as Atom and Archetype. Jung's elaborate analysis of more than 400 of Pauli's dreams is documented in Psychology and Alchemy.

    The German annexation of Austria in 1938 made him a German citizen, which became a problem for him in 1939 after the outbreak of World War II. In 1940, he tried in vain to obtain Swiss citizenship, which would have allowed him to remain at the ETH.[13]

    Pauli moved to the United States in 1940, where he was employed as a professor of theoretical physics at the Institute for Advanced Study. In 1946, after the war, he became a naturalized citizen of the United States and subsequently returned to Zurich, where he mostly remained for the rest of his life. In 1949, he was granted Swiss citizenship.

    In 1958, Pauli was awarded the Max Planck medal. In that same year, he fell ill with pancreatic cancer. When his last assistant, Charles Enz, visited him at the Rotkreuz hospital in Zurich, Pauli asked him: "Did you see the room number?" It was number 137. Throughout his life, Pauli had been preoccupied with the question of why the fine structure constant, a dimensionless fundamental constant, has a value nearly equal to 1/137. Pauli died in that room on 15 December 1958.[14]

    Scientific research

    Niels Bohr, Werner Heisenberg, and Wolfgang Pauli, ca. 1935

    Pauli made many important contributions as a physicist, primarily in the field of quantum mechanics. He seldom published papers, preferring lengthy correspondences with colleagues such as Niels Bohr and Werner Heisenberg, with whom he had close friendships. Many of his ideas and results were never published and appeared only in his letters, which were often copied and circulated by their recipients.

    Pauli proposed in 1924 a new quantum degree of freedom (or quantum number) with two possible values, in order to resolve inconsistencies between observed molecular spectra and the developing theory of quantum mechanics. He formulated the Pauli exclusion principle, perhaps his most important work, which stated that no two electrons could exist in the same quantum state, identified by four quantum numbers including his new two-valued degree of freedom. The idea of spin originated with Ralph Kronig. George Uhlenbeck and Samuel Goudsmit one year later identified Pauli's new degree of freedom as electron spin.

    In 1926, shortly after Heisenberg published the matrix theory of modern quantum mechanics, Pauli used it to derive the observed spectrum of the hydrogen atom. This result was important in securing credibility for Heisenberg's theory.

    Pauli introduced the 2 × 2 Pauli matrices as a basis of spin operators, thus solving the nonrelativistic theory of spin. This work is sometimes said to have influenced Paul Dirac in his creation of the Dirac equation for the relativistic electron, though Dirac stated that he invented these same matrices himself independently at the time, without Pauli's influence. Dirac invented similar but larger (4x4) spin matrices for use in his relativistic treatment of fermionic spin.

    In 1930, Pauli considered the problem of beta decay. In a letter of 4 December to Lise Meitner et al., beginning, "Dear radioactive ladies and gentlemen", he proposed the existence of a hitherto unobserved neutral particle with a small mass, no greater than 1% the mass of a proton, in order to explain the continuous spectrum of beta decay. In 1934, Enrico Fermi incorporated the particle, which he called a neutrino, into his theory of beta decay. The neutrino was first confirmed experimentally in 1956 by Frederick Reines and Clyde Cowan, two and a half years before Pauli's death. On receiving the news, he replied by telegram: "Thanks for message. Everything comes to him who knows how to wait. Pauli."[15]

    In 1940, he re-derived the spin-statistics theorem, a critical result of quantum field theory which states that particles with half-integer spin are fermions, while particles with integer spin are bosons.

    In 1949, he published a paper on Pauli–Villars regularization: regularization is the term for techniques which modify infinite mathematical integrals to make them finite during calculations, so that one can identify whether the intrinsically infinite quantities in the theory (mass, charge, wavefunction) form a finite and hence calculable set which can be redefined in terms of their experimental values, which criterion is termed renormalization, and which removes infinities from quantum field theories, but also importantly allows the calculation of higher order corrections in perturbation theory.

    Pauli made repeated criticisms of the modern synthesis of evolutionary biology,[16][17] and his contemporary admirers point to modes of epigenetic inheritance as supportive of his arguments.[18]

    Personality and reputation

    Wolfgang Pauli, ca. 1924

    The Pauli effect was named after the anecdotal bizarre ability of his to break experimental equipment simply by being in the vicinity. Pauli was aware of his reputation and was delighted whenever the Pauli effect manifested. These strange occurrences were in line with his investigations into the legitimacy of parapsychology, particularly his collaboration with C. G. Jung on the concept of synchronicity.

    Regarding physics, Pauli was famously a perfectionist. This extended not just to his own work, but also to the work of his colleagues. As a result, he became known in the physics community as the "conscience of physics," the critic to whom his colleagues were accountable. He could be scathing in his dismissal of any theory he found lacking, often labelling it ganz falsch, utterly wrong.

    However, this was not his most severe criticism, which he reserved for theories or theses so unclearly presented as to be untestable or unevaluatable and, thus, not properly belonging within the realm of science, even though posing as such. They were worse than wrong because they could not be proven wrong. Famously, he once said of such an unclear paper: It is not even wrong!"[2]

    His supposed remark when meeting another leading physicist, Paul Ehrenfest, illustrates this notion of an arrogant Pauli. The two met at a conference for the first time. Ehrenfest was familiar with Pauli's papers and was quite impressed with them. After a few minutes of conversation, Ehrenfest remarked, "I think I like your Encyclopedia article [on relativity theory] better than I like you," to which Pauli shot back, "That's strange. With me, regarding you, it is just the opposite."[19] The two became very good friends from then on.

    A somewhat warmer picture emerges from this story, which appears in the article on Dirac:
    "Werner Heisenberg [in Physics and Beyond, 1971] recollects a friendly conversation among young participants at the 1927 Solvay Conference, about Einstein and Planck's views on religion. Wolfgang Pauli, Heisenberg, and Dirac took part in it. Dirac's contribution was a poignant and clear criticism of the political manipulation of religion, that was much appreciated for its lucidity by Bohr, when Heisenberg reported it to him later. Among other things, Dirac said: "I cannot understand why we idle discussing religion. If we are honest – and as scientists honesty is our precise duty – we cannot help but admit that any religion is a pack of false statements, deprived of any real foundation. The very idea of God is a product of human imagination. [...] I do not recognize any religious myth, at least because they contradict one another. [...]" Heisenberg's view was tolerant. Pauli had kept silent, after some initial remarks. But when finally he was asked for his opinion, jokingly he said: "Well, I'd say that also our friend Dirac has got a religion and the first commandment of this religion is 'God does not exist and Paul Dirac is his prophet'". Everybody burst into laughter, including Dirac.
    Many of Pauli's ideas and results were never published and appeared only in his letters, which were often copied and circulated by their recipients. Pauli may have been unconcerned that much of his work thus went uncredited, but when it came to Heisenberg's world-renowned 1958 lecture at Göttingen on their joint work on a unified field theory, and the press release calling Pauli a mere "assistant to Professor Heisenberg", Pauli became offended, denouncing Heisenberg's physics prowess. The deterioration between them resulted in Heisenberg ignoring Pauli's funeral, and writing in his autobiography that Pauli's criticisms were overwrought.[20] Pauli was elected a Foreign Member of the Royal Society (ForMemRS) in 1953.[2] In 1958 he became foreign member of the Royal Netherlands Academy of Arts and Sciences.[21]

    Personal life

    Buste of Wolfgang Pauli (1962)

    In May 1929, Pauli left the Roman Catholic Church. In December of that year, he married Käthe Margarethe Deppner. The marriage was an unhappy one, ending in divorce in 1930 after less than a year. He married again in 1934 to Franziska Bertram (1901–1987). They had no children.

    Bibliography

  • Pauli, Wolfgang; Jung, C. G. (1955). The Interpretation of Nature and the Psyche. Ishi Press. ISBN 4-87187-713-2.
  • Pauli, Wolfgang (1981). Theory of Relativity. New York: Dover Publications. ISBN 0-486-64152-X.
  • Pauli, Wolfgang; Jung, C. G. (2001). ed. C. A. Meier, ed. Atom and Archetype, The Pauli/Jung Letters, 1932–1958. Princeton, New Jersey: Princeton University Press. ISBN 978-0-691012-07-0.

Inequality (mathematics)

From Wikipedia, the free encyclopedia https://en.wikipedia.org/wiki/Inequality...