The Latest Alaska News, From San Francisco
I just returned from a week in the company of 9,892 scientists who gathered in San Francisco for the annual meeting of the American Geophysical Union. Amid thousands of topics ranging from hummingbird habitat to solar explosions were Alaska-related stories, many presented by the dozens of Alaska scientists in San Francisco. Among the news:
• A large earthquake in 1912 split spruce trees along the path of the Denali fault in the same area where the planet’s largest earthquake in 2002 struck, according to David Schwartz of the U.S. Geological Survey in Menlo Park, California.
• Since the Good Friday earthquake in March 1964, parts of the Kenai Peninsula have risen more than three feet and continue to rise. Jeff Freymueller of the University of Alaska’s Geophysical Institute and his colleagues have clocked the Kenai’s rise using GPS receivers, comparing their readings to a road-leveling survey performed by state workers just after the earthquake in 1964.
• Methane trapped in permafrost on Alaska’s north slope may have a unique release mechanism to the atmosphere—caribou. Yongwon Kim of the International Arctic Research Center monitors gases emitted by the tundra about 12 miles south of Deadhorse near Prudhoe Bay. When he saw dozens of caribou walking through his study site on a recent summer day, he hurried over to place a plastic-coated box with monitoring equipment on the tundra where the caribou had passed. He found twice as much release of methane—a greenhouse gas held captive in cold soils of the north—after the caribou had walked through. With caribou herds numbering in the hundreds of thousands, Kim argued that the animals could be triggering a significant release of methane with their hooves.
• During a recent winter, temperatures at the surface of the ground beneath the snowpack at Council, Alaska, remained warm enough for soil microbes to remain active all winter. Matthew Sturm of the Cold Regions Research and Engineering Laboratory and Ken Tape of the Geophysical Institute were among the scientists who measured the ground-surface temperatures during the winter at Council, east of Nome. They contend that warmer air temperatures are part of a cycle driven in an almost intelligent way by shrubs in treeless areas of Alaska. When shrubs increase in density, the scientists said, the woody plants accumulate blown snow, which insulates the soil. This allows microbes to be more active in breaking down organic matter, providing more nutrients to plants, which makes for more shrubs.
• Scientists used infrasound arrays, including one in Fairbanks, to rule out possible causes of the Space Shuttle Columbia’s explosion over Texas in February 2003. Infrasound waves are sound waves too low for humans to hear, but specialized microphones can be used to detect them. Alaska scientists John Olson, Charles Wilson and Daniel Osborne of the Geophysical Institute have detected certain types of aurora, storms at sea, and the jiggling of the Alaska Range during the Denali fault earthquake with their Fairbanks infrasound microphone array. Hank Bass of the University of Mississippi reported on how he and others used 10 infrasound stations, including the one in Fairbanks, to determine that the shuttle’s destruction upon reentering Earth’s atmosphere was not caused by a meteorite or a sprite, lighting that strikes upward during thunderstorms.
