» Chaitén Photoessay
Making Science Connections, Worldwide
Since 2009, PNW Research Station scientists Fred Swanson and Charlie Crisafulli
have been traveling to Chile to study the effects of the eruption of Chaitén
Volcano, a 3,681-foot-tall caldera volcano that erupted violently in May 2008.
Their visits, supported by the U.S. Forest Service and the National Science
Foundation and carried out in collaboration with Chilean academics, national
park officials, and other U.S. and Chilean colleagues, have launched a study
to document the ecological responses to the Chaitén eruption and to
compare them with those observed in the intensively studied Mount St. Helens
landscape. Now in their fourth year, these visits have already begun yielding
insight on the response of nearby forests, rivers, and towns to volcanic disturbance—and
on the striking similarities between volcanic landscapes and their responses
in the northern and southern hemispheres.
Browse this site to learn more about
the changes observed in Chile so far and how Crisafulli and Swanson are
making connections between their work at Mount
St. Helens and at Chaitén.
The Eruption at Chaiten
image with locations.
Chaitén is a small volcano located in Pumalin Park, in the southern
part of Chile. Prior to Chaitén’s 2008 eruption, which followed
several days of earthquake activity, many nearby residents and visitors did
not know that the 962-meter-tall (3,156 feet) flat-topped structure was a
volcano, which added to their surprise when it erupted. The eruption itself
attracted attention worldwide—as it was the first major rhyolite eruption
in nearly a century anywhere on Earth. Initially, it launched fine-grained
rock debris more than 20 kilometers (65,000 feet) into the atmosphere. Over
the following months, the volcano maintained an eruption column several kilometers
high and exhibited intermittent periods of more explosive phases. Wind blew
plumes of tephra in a broad arc to the east across Argentine Patagonia and
the Atlantic Ocean.
Sometime during the first week of the eruption, a blast
cloud of hot rock debris surged down the north flank of Chaitén, knocking
down trees and scorching foliage on trees around the edge of a 4 km2 zone.
began about 10 days after the start of the eruption and washed a great deal
of tephra from the surrounding hillslopes, sending sediment-rich flood waters
into streams and rivers. The volcano’s lava dome grew within the caldera
in the two years immediately following the eruption.
image with locations.
January 2012 will mark the fourth consecutive year that station scientists
Fred Swanson and Charlie Crisafulli and U.S. collaborators have traveled
to Chile during the southern hemisphere summer to document the ecological
impacts of the eruption on nearby forests and rivers and to investigate
the pace and pattern of plant and animal response.
The landscape affected
by Chaitén’s 2008 eruption has
remained dynamic since the eruption.
Plant survival was widespread, but varied dramatically based on the
types and intensities of volcanic disturbance.
species of trees in the former forest that were leveled by the powerful blast
sent out new shoots as early as the first post-eruption growing season. The
success of this regrowth is not known, but is a topic of investigation. By
the third post-eruption growing season, numerous species of plants and animals
had established in the affected areas. These included tree, shrub, and herb
species as well as animals such as birds, amphibians, insects, and spiders.
Sediment production remains above pre-eruption levels. Four bridges in the
vicinity of the town of Chaitén offer views of the volcano and the
surrounding rivers and forests that were affected by the 2008 eruption. These
locations provide ideal vantage points for telling the stories of the volcano’s
eruption and its aftermath.
Rio Rayas Bridge
Rayas bridge is located 2.5 kilometers (1.5 miles) north-northeast
of Chaitén’s caldera rim, in an area that was peppered
with gravel-sized tephra on May 6, 2008. The gravel that fell into
the forest stripped leaves and small twigs from the canopy and incorporated
this organic material into deposits that accumulated on the ground,
up to 25 cm (9.8 inches) thick in some places. Learn more.
Rio Los Gigios Bridge
Los Gigios, a small stream flowing 2 kilometers (1.2 miles) from Chaitén’s
caldera rim to this bridge, experienced many effects of the eruption.
The adjacent forest was scorched by a blast originating from the volcano’s
eruption column that sent a hot sand- and gravel-charged surge downhill,
snapping and toppling trees and blasting off their limbs. Learn
Rio Chaiten Bridge
Chaitén is located 10 kilometers (6.2 miles) due south of Chaitén
volcano. The area was inundated by a large volume of sediment triggered
by intense rainfall following the eruption, which flooded the town and
deposited 1 to 2 meters (3 to 6 feet) of sand and gravel. Much of the
material in these deposits originated as tephra fall in the steep headwaters
of the Rio Chaiten. Learn more.
Rio Amarillo Bridge
Rio Amarillo bridge (pictured in the first two photos) is located at
the small developed area of Amarillo, about 20 kilometers (12 miles)
southeast of Chaitén Volcano. The Rio Amarillo watershed experienced
up to about 20 cm (9 inches) of tephra fall, but at this location, tephra
fall was less than 10 cm (4 inches), so the surrounding landscape does
not show much change besides an increase in sediment flow. Learn
Further Readings, Contributors, Acknowledgments