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

Drought and recovery

These images from the NASA Earth Observatory show areas of drought (brown = below average plant growth) and excess plant growth (green = above average plant growth).

Northern Iraq is suffering a severe drought. Much of the country’s grain is dependent on seasonal rainfall rather than irrigation:

Credit: NASA/Terra/MODIS
Credit: NASA/Terra/MODIS

Grain-producing regions of Afghanistan, on the other hand, are recovering from a period of drought, with the wheat crop responding well to spring rains:

Credit: NASA/Terra/MODIS
Credit: NASA/Terra/MODIS

Satellite imagery like this gives governments and aid agencies a quick way to analyze conditions on the ground.

Iraq image: Earth Observatory — Drought in Iraq

Afghanistan image: Earth Observatory — Crop Recovery in Afghanistan

Grace and Peace

Aral Sea — environmental disaster

This is all that is left of what was the Earth’s fourth largest lake only 50 years ago.

From NASA’s Earth Observatory: Dust Over the Aral Sea.

Credit: NASA
Credit: NASA/Terra MODIS

In the 1960s, the Soviet Union started diverting most of the water from the rivers that fed the Aral Sea to irrigation, primarily for cotton. This led to an environmental catastrophe that continues to this day. Effects of this include:

  • Drying up of the lake, which is now only 10% of its former size.
  • Increasing salinity of the lake. Only the northernmost basin still has low enough salinity to support fish. Most native species are gone.
  • Creation of dust storms blowing off of the dry lake bed. In addition to salt, this dust contains pesticides and industrial wastes, which cause health problems for residents living downwind.
  • Widespread unemployment and other economic hardships.

(For an animation of the shrinking of the Aral Sea, go to http://en.wikipedia.org/wiki/File:Aral_Sea.gif)

Our actions as humans always have consequences. Some consequences can be predicted, others are unforeseen; some are small, and others are major. What will the consequences of our current activities be? What activities are we now involved in that will have long-term negative consequences in the future?

“A prudent man sees danger and takes refuge, but the simple keep going and suffer for it.” (Prov 22:3 NIV)

Grace and Peace

Lake Eyre, Australia

I love this picture, as only a geologist who loves streams and sediments could.

From NASA’s Earth Observatory site: Rare Refill of Lake Eyre, Australia’s Simpson Desert.

LakeEyreAustralia
Credit: NASA/Landsat-5

From the EO description:

Waves in central Australia’s Simpson Desert usually come in the form of sand dunes. In these images, they ripple in long vertical lines across the surface of the desert. But occasionally, summer rain from northern Australia flows down into the desert, filling dry river channels and empty lake beds. Very occasionally, the water reaches a vast lake bed called Lake Eyre, turning it into a shallow inland sea where birds flock to breed.
In early 2009, heavy rains brought major flooding to nearly every river system in Queensland, Australia. By May, the water had made its way south and had started to fill Lake Eyre. The top image provides a natural-color view of water pouring into the lake through one of many channels that drain the desert during the rainy season. The muddy brown water spreads into the lake in a triangular alluvial fan.

Waves in central Australia’s Simpson Desert usually come in the form of sand dunes. In these images, they ripple in long vertical lines across the surface of the desert. But occasionally, summer rain from northern Australia flows down into the desert, filling dry river channels and empty lake beds. Very occasionally, the water reaches a vast lake bed called Lake Eyre, turning it into a shallow inland sea where birds flock to breed.

In early 2009, heavy rains brought major flooding to nearly every river system in Queensland, Australia. By May, the water had made its way south and had started to fill Lake Eyre. [This] image provides a natural-color view of water pouring into the lake through one of many channels that drain the desert during the rainy season. The muddy brown water spreads into the lake in a triangular alluvial fan.

Each depositional environment in this image will produce sediments with a distinct combination of grain size, sedimentary structures (various types of ripples and dunes, as well as things like mud cracks), mineralogy (evaporites in the lake basin), and trace fossils (footprints, burrows). The main depositional environments in this image are stream channel, alluvial fan/delta, arid lake, shoreline, and sand dune. Within each of these there are more specific depositional sites, such as near-shore or deeper water lake deposits. These are the types of things that enable geologists to interpret the depositional environments of ancient sedimentary rocks.

Grace and Peace

Lake Powell images, 1999 to 2009

NASA’s Earth Observatory has a series of images from 1999 to 2009 showing fluctuating water levels in Lake Powell in southeastern Utah. Lake Powell is formed by Glen Canyon Dam on the Colorado River in northern Arizona.

Credit:
Lake Powell 1999, Credit: NASA Landsat 5
Lake Powell 2008, Credit: NASA Landsat 5
Lake Powell 2008, Credit: NASA Landsat 5

Earth Observatory has a “play” link to watch the images in played in order.

From the description at the NASA Earth Observatory site:

The Colorado River flows from the Rocky Mountains in Colorado through the southwestern United States. Along its route, the river passes through an elaborate water-management system designed to tame the yearly floods from spring snowmelt and to provide a reliable supply of water for residents as far away as California. The system is both appreciated for the water it provides and criticized for the environmental and cultural losses it has created.

Among the dams on the Colorado is Glen Canyon Dam in Arizona, which creates Lake Powell—a deep, narrow, meandering reservoir—upstream in southern Utah. In the early twenty-first century, this modern marvel of engineering faced an ancient enemy: severe, prolonged drought in the American Southwest. Combined with water withdrawals that many believe are not sustainable, the drought has taken its toll on the water level in Lake Powell over the past decade.

Grace and Peace