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» 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

Chaiten volcano. Remote sensing image with locations. Remote sensing 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. Intense rainfall 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.

 

Research Trips

Chaiten volcano. Remote sensing image with locations.
Remote sensing 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.

Bullet. Plant survival was widespread, but varied dramatically based on the types and intensities of volcanic disturbance.

Bullet.Several 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

 

Rio Raya bridge, looking downstream, south bank (January 2011).Rio 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

 

Rio Gigios looking (March 2009). Rio 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 more.

Rio Chaiten Bridge

 

Rio Chaiten/Blanco (March 2009).Rio 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 tributary (January 2010).The 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 more.


 

 

 

 

Further Readings, Contributors, Acknowledgments

 

US Forest Service - Pacific Northwest Research Station
Last Modified: Thursday,28March2013 at13:57:48CDT


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