Additionally, the Satellite Products and Services Division SPSD provides government officials and the public with visualizations of current and past eruptions, along with advisories in relation to any recent volcanic activity. Below are some of our favorite satellite views of other volcanoes around the world, which demonstrate their awesome power—and sobering destruction—as seen from Earth orbit. Site Map Contact Us. May 18, Photograph of Mount St. Helens taken on May 18, , by Joseph Rosenbaum.
Courtesy of USGS. Mount St. Credit: NASA. Team Work Makes the Dream Work None of these advancements would be possible without the amazing people and organizations that collaborate to make the system work.
The reddish-pink coloration toward the center of the frame indicates the ash plume. Displayed here are four of the many ways the satellite viewed the event. Helens has been the most active Cascade Range volcano, with about 20 eruptive periods. Over the millennia, debris avalanches, pyroclastic flows, lava flows, and mudflows have built, torn apart, and rebuilt the volcano. From the May 18, , eruption to , the volcano erupted an additional 21 times.
These were mostly dome-building eruptions, although small pyroclastic flows and mudflows occurred also. Mount St. Helens began to erupt again in September , with earthquakes, ash and steam plumes, and a dome-building lava flow.
The volcano was quiet from until September , when swarms of small earthquakes began. Plumes of steam and ash rose from new vents, ballistic explosions hurled boulders across the crater, and small mudflows traveled down stream channels close to the mountain.
A large new lava dome has grown at an impressive rate within the crater. By spring , the newest dome was already taller than the dome formed from to Helens has a rich eruptive history, and geologists think that the volcano will likely be active off and on in years to come. The repeated episodes of eruption followed by ecological recovery make Mount St.
Helens a fascinating place to learn about the forces of nature and resiliency of life. Bird survival during the eruption depended on the distance of birds from the volcano and disturbance zone. All birds died throughout the entire square-mile blast area and in areas crushed by the debris avalanche.
In contrast, many birds outside the blast area but in the path of mudflows likely fled to safety, and birds in tephra-fall areas were temporarily displaced. The power of flight gives birds tremendous ability to move freely, and scientists observed some birds flying into the blast area within days after the eruption. These early immigrants stayed and nested wherever habitat and food were available. After the eruption, the pattern of bird colonization was strongly influenced by habitat structure and complexity, which differed substantially across the disturbance zones.
These differences determined which bird species, and how many bird species, were found in each zone. Birders can print a complete bird checklist for the Mount St. Helens area. Conditions and recolonization within the pyroclastic flow zone The pre-eruption forest was completely destroyed and covered with rocky rubble, leaving a barren habitat.
Only bird species that nested and foraged on the ground, such as the American pipit Anthus rubescens and horned lark Eremophila alpestris , were able to live in the pyroclastic flow zone. Conditions and recolonization within the debris avalanche zone The debris avalanche scoured parts of the Toutle River valley and buried the rest, replacing the former valley with an unusual topography of rock-and-sand hummocks interspersed with natural hollows where small ponds and seeps formed.
The Toutle River carved a canyon through the avalanche deposit, creating terraces and a dynamic flood plain. Initially, these diverse habitats offered habitat only for ground-nesting birds like the common nighthawk Chordeiles minor and killdeer Charadrius vociferus , and a few species of waterfowl.
But the ponds and seeps developed into biological hotspots, filled with algae, reeds, and cattails and surrounded with thickets of willows, alder, and herbs. Plants also grew along the margins of the avalanche deposit. A spectacularly diverse assemblage of birds colonized all these habitats as they developed.
Conditions and recolonization within the blowdown and scorch zones The trees toppled by the blast and standing dead trees snags created an abundant supply of large dead wood, used by several bird species. Tree saplings and shrubs buried in late-winter snowbanks survived, as did many dormant plants, creating habitats with some complexity. Many bird species colonized these small patches of surviving vegetation. Birds most likely abandoned these areas temporarily, but scientists found many bird species had returned to the tephra-fall zone within a few weeks.
Over the next few years, scientists found the same species of birds in the tephra-fall zone that they found in nearby undisturbed sites, although the total number of individual birds using the ash-covered forest floor was likely reduced for the first few years after the eruption. More bird species colonized the disturbance zones as habitat complexity increased. In the years since the eruption, habitat complexity increased in all disturbance zones as surviving plants grew and spread and other plant species became established.
Scientists found that additional bird species colonized the blast area as habitat complexity increased, and that the appearance of new species was closely connected to the developing vegetation. Bird colonization of streamside vegetation The most dramatic threshold since the eruption occurred about 10 years after the eruption. Willow Salix spp. These species nest or forage in the woody riparian vegetation. Bird colonization of cottonwood trees As cottonwood trees Populus trichocarpa grew in moist areas, two additional bird species, warbling vireo Vireo gilvus and black-headed grosbeak Pheucticus melanocephalus colonized.
The vireo and grosbeak used the extensive canopies of foot-tall cottonwood trees for nesting and foraging. Bird colonization of conifer stands Conifer saplings that survived the eruption beneath snowbanks had grown into small, dense stands by the mids and ushered in the arrival of hermit thrush Catharus guttatus , which forage on the ground under dense cover, and seed-eaters like pine siskins Carduelis pinus.
Bird colonization of ponds, wetlands, and lakes Two large new lakes, more than ponds, and dozens of wetlands formed on the debris avalanche deposit. These water bodies provide habitat for many aquatic bird species, including puddle ducks such as the mallard Anas platyrhynchos , diving ducks such as the ring-necked Aythya collaris , and grazers like the Canada goose Branta canadensis.
Spotted sandpipers Actitis macularia feed and nest along the lake shores. Great blue herons Ardea herodias , which stand up to 4 feet tall, hunt the wetlands and shallow pond waters, and hard-to-spot soras Porzana carolina , small birds in the rail family, live in the wetlands. The return of raptors Birds of prey have come back to the volcanic landscape as their food sources increased. For example, osprey Pandion haliaetus and bald eagles Haliaeetus leucocephalus forage for fish in the lakes, red-tailed hawks Buteo jamaicensis soar the skies hunting for rodents on the ground, and American kestrels Falco sparverius hover, then pounce on grasshoppers and other prey.
The short-eared owl Asio flammeus , which lives in open country and sometimes hunts by day, has also returned. Several other raptors use the area during the summer or while traveling through on their migration routes. Scientists found that in the early years after the eruption, the bird assemblages, or groups of species, in the disturbance zones were quite different, corresponding to the dramatically different habitats offered.
As plant communities developed, however, creating habitats with more structure and complexity, more bird species colonized each zone and the assemblages for the zones developed some similarities. Even so, as recently as , significant differences still remained among the bird assemblages for the different disturbance zones. Bird colonization into the future Only the initial stages of succession have occurred among birds in the Mount St.
Helens blast area. In the first quarter century after the eruption, scientists found that more and more bird species colonized the blast area, with the total number of bird species steadily increasing. Further stages of succession—or the replacement of one species by another—have not occurred yet among birds. If no large eruptions or other large disturbances such as wildfire occur in the near future, scientists expect that bird species replacements will occur as forests become widespread across the Mount St.
Helens landscape, and birds of open habitats are replaced by forest bird species. The eruption in late and early has been confined, for the most part, to the crater. Scientists expect that as succession occurs, the bird assemblages in the disturbance zones will become more and more similar, eventually converging into an assemblage of bird species similar to those of other Pacific Northwest forests.
Before the eruption, the Mount St. Helens area supported about 35 small to midsize mammal species, not including bats. Although the volcano dramatically altered a vast terrain, scientists found that a surprisingly large number of these mammal species had survived in many locations. Survival was related to the type and severity of volcanic disturbance and differed considerably across the volcanic disturbance zones.
Within 10 years of the eruption, nearly all the mammal species found in the southern Washington Cascade Range had returned to the blast area. The mammal assemblages, or groupings of species, were quite different in the various disturbance zones. Scientists attribute many of these differences to, first, the amounts and types of the pre-eruption forest components that remained after the eruption, such as fallen trees, standing dead trees, and surviving patches of vegetation; and, second, the rate at which new vegetation developed.
The down trees, surviving plants, and colonizing vegetation provided a complex ground layer that offered abundant cover and hiding places and also produced diverse food items including seeds, insects, green plants, and roots. This area thus provided all habitat needs for a variety of ground-dwelling rodents such as the Cascade golden-mantled ground squirrel Spermophilus saturatus , yellow-pine chipmunk Tamias amoenus , deer mouse Peromyscus maniculatus , and insectivores such as the montane shrew Sorex monticolus.
These small mammals were the prey for predators like the coyote Canis latrans , short-tailed weasel or ermine Mustela erminea , and longtail weasel Mustela frenata. Two midsize aquatic predators, the American mink Mustela vison and northern river otter Lutra canadensis , inhabit the blowdown, debris avalanche, and pyroclastic flow zones, where the mink and otters eat crayfish, amphibians, and fish, in addition to other aquatic and terrestrial prey.
Midsize herbivorous mammals, such as the American beaver Castor canadensis and common porcupine Erethizon dorsatum , colonized the blowdown zone once their forage base of bark, leaves, twigs, and buds was established.
On the pumice plain in the severely altered pyroclastic flow zone, none of the former forest remained after the eruption. Vegetation that developed since the eruption was generally sparse and close to the ground except for the springs and seeps, discussed below , providing little habitat for most mammals. Here, the dominant mammal was the deer mouse. About 12 years after , the northern pocket gopher Thomomys talpoides reached the pumice plain and became established. Gophers move primarily through their tunnel digging, which explains why the species took so long to reach the plain.
A handful of cool springs and seeps emerged on the pumice plain, and small patches of dense, lush willow and herb plant communities developed around these wet spots. Technical Announcements. Employees in the News. Emergency Management. Survey Manual. Prior to , Mount St. Helens had the shape of a conical, youthful volcano sometimes referred to as the Mount Fuji of America. During the eruption the upper m 1, ft of the summit was removed by a huge debris avalanche, leaving a 2 x 3.
It is primarily an explosive dacite volcano. Mount St. Helens is primarily an explosive dacite volcano with a complex magmatic system. The volcano was formed during four eruptive stages beginning about , years ago and has been the most active volcano in the Cascade Range during the Holocene.
The batholith limits magma from rising to the east of Mount St. A dense wall of rock beneath these metasediments, also revealed by the seismic array , may actually be part of this lost landscape, providing a westward stop for the flow of magma, says Jade Crosbie , a geophysicist with the USGS in Lakewood, Colorado, and part of the iMUSH team. While the iMUSH analyses help sharpen our view deep inside the planet, the picture remains far from complete, Moran says.
Today, the remains of Siletzia can be seen only piecemeal at the surface, partially buried by flows of now solidified lava and soils studded with trees. This leaves scientists debating where the suture zone—and its role in magmatic direction— precisely lies.
As the researchers continue to sort through the sea of other data from iMUSH, many more questions dance in their heads. How does the system change over time? How quickly does the magma move?
How does such a vast zone of partly melted rock focus into a volcanic pinprick on the surface? Each potential answer helps shape our understanding of how and why volcanoes erupt, which can help researchers connect what happens at one volcano to the broader picture of volcanism around the world, says seismologist Helen Janiszewski of the University of Hawaii at Manoa.
Since that fateful day in , Mount St. Helens has awoken multiple times , even as the population living in its shadow has grown. That confluence reinforces the need to keep close watch on this particular peak, and scientists have embraced that task. All rights reserved. Science News. Helens isn't where it should be. Scientists may finally know why.
The gaping crater of Mount Saint Helens, seen here on September 5, , is a reminder of the deadly volcanic blast that rocked the Pacific Northwest 40 years ago.
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