Sarychev Peak eruption

From NASA’s Earth Observatory: Sarychev Peak Eruption, Kuril Islands, Russia.

Credit: NASA/International Space Station astronauts
Credit: NASA/International Space Station Expedition 20 crew

From the Earth Observatory description:

A fortuitous orbit of the International Space Station allowed the astronauts this striking view of Sarychev Volcano (Kuril Islands, northeast of Japan) in an early stage of eruption on June 12, 2009. […] Ash from the multi-day eruption has been detected 2,407 kilometers east-southeast and 926 kilometers west-northwest of the volcano, and commercial airline flights are being diverted away from the region to minimize the danger of engine failures from ash intake.

This detailed astronaut photograph is exciting to volcanologists because it captures several phenomena that occur during the earliest stages of an explosive volcanic eruption. The main column is one of a series of plumes that rose above Matua Island on June 12. The plume appears to be a combination of brown ash and white steam. The vigorously rising plume gives the steam a bubble-like appearance; the surrounding atmosphere has been shoved up by the shock wave of the eruption. The smooth white cloud on top may be water condensation that resulted from rapid rising and cooling of the air mass above the ash column. This cloud is probably a transient feature: the eruption plume is starting to punch through. The structure also indicates that little to no shearing wind was present at the time to disrupt the plume. […]

By contrast, a cloud of denser, gray ash—probably a pyroclastic flow—appears to be hugging the ground, descending from the volcano summit. The rising eruption plume casts a shadow to the northwest of the island (image top). Brown ash at a lower altitude of the atmosphere spreads out above the ground at image lower left. Low-level stratus clouds approach Matua Island from the east, wrapping around the lower slopes of the volcano. Only about 1.5 kilometers of the coastline of Matua Island (image lower center) are visible beneath the clouds and ash.

I’ve got this one set as my desktop background this week.

Grace and Peace

Eruption of underwater volcano, Tonga

Here’s a video of an eruption of an underwater volcano near the South Pacific island of Tonga on March 19, 2009:

News articles:

London Times: Underwater volcano sends huge columns of ash into Pacific sky

Honolulu Advertiser: 7.9 quake off Tonga could intensify volcano’s eruption

From NASA’s Earth Observatory: Submarine Eruption in the Tonga Islands:

Credit: NASA
Credit: NASA

Grace and Peace

Australia flooding images

While the southern parts of Australia have been burning over the past two months, the northern parts have experienced cool weather and heavy rainfall. The following images are of Normanton, Queensland, which has been cut off by flooding for several weeks.

Credit: NASA, EO-1
Credit: NASA, EO-1
Credit: NASA, EO-1
Credit: NASA, EO-1

The first image is in natural color; the second is enhanced with infrared, which gives a clearer indication of ground that is covered by water.

From NASA’s Earth Observatory: Floods in Australia.

Grace and Peace

Chaiten Volcano, Chile

After 9000 years of dormancy, Chaiten Volcano, in a remote part of southern Chile, has been in an eruptive phase since May 2008. NASA’s Earth Observatory posted these images of the 1/19/09 dome collapse yesterday:

chaiten1
Credit: NASA (Terra satellite)
NASA (Terra satellite)
Credit: NASA (Terra satellite)

These images above don’t do justice to the high resolution versions available at Earth Observatory:

NASA (Terra satellite)
Credit: NASA (Terra satellite). The river formerly went south of the town of Chaiten (meandering gray channel), but as the stream bed clogged with debris, it changed course and now goes right through the middle of the town.

In these false color images, the red areas are vegetation, and the gray areas are volcanic ash and mud.

A dome collapse is what it sounds like. Chaiten Volcano is similar to Mt. St. Helens in Washington, in that it produces viscous lava that piles up in a dome, as opposed to the fluid lava that is produced by basaltic volcanoes such as those in Hawaii. As the dome grows, it can become unstable and collapse, which is sort of like removing a cork from a bottle of champagne. The result is an eruption of ash, such as what you see in these images. (For a picture of the Chaiten dome before its collapse, click here).

This volcano is in an area with a low population density. The town of Chaiten has been evacuated since the volcano rumbled into activity eight months ago.

The Volcanism Blog gives regular updates on Chaiten Volcano.

Grace and Peace

Mapping the harvest

From NASA’s Earth Observatory this week: Poor harvest in Kenya

NASA
Credit: NASA

From NASA’s description:

Ten million people could face hunger in Kenya after a poor harvest, Kenya’s government warned on January 9, 2009. According to the Associated Press, the government declared a state of emergency to free up funds for food aid.

This image, which shows vegetation conditions between January 1 and January 10, 2009, shows part of the reason for the failed crops. Developing drought settled over eastern Kenya, slowing plant growth. Areas in which plants were growing less vigorously than average are brown, while areas in which plants were growing well are green.

Satellite data like this, if properly used, could help relieve the suffering of millions.

Grace and Peace

Ike damage

NASA Earth Observatory has some pictures of damage done by Hurricane Ike:

The writeup explains the value of images taken from an airplane, as compared to the value of satellite shots:

The photos were taken to help communities respond to the disaster. Aerial photography is valuable because it provides a highly detailed view of damage in a small area. Satellites, on the other hand, can provide a wide-scale view, useful in mapping out the extent of a disaster. For example, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite observed flooding over hundreds of kilometers of the Gulf Coast on September 17, but could not image damage down to the street level as these photographs do. Also, unlike a satellite, an airplane is capable of flying beneath clouds.

This also illustrates, once again, the dangers of building on low-lying barrier islands.

Grace and Peace