Geology News And Research - April 2009 Archives

Studies offer new picture of Lake Tahoe's earthquake potential (4/30/2009)

Two newly published papers provide a deeper look at earthquake vulnerability for the Lake Tahoe region ...> Full Article

Satellite imagery shows fragile Wilkins Ice Shelf destabilized (4/29/2009)

Satellite images show that icebergs have begun to calve from the northern front of the Wilkins Ice Shelf, indicating that the huge shelf has become unstable. This follows the collapse three weeks ago of the ice bridge that had previously linked the Antarctic mainland to Charcot Island. ...> Full Article

Geoscientists meet to discuss Rocky Mountain geology (4/29/2009)

Geological Society of America holds regional meeting in Orem, Utah, May 11-13 ...> Full Article

New blow for dinosaur-killing asteroid theory (4/28/2009)

Impact didn't lead to mass extinction 65 million years ago, geologists find ...> Full Article

Critical turning point can trigger abrupt climate change (4/27/2009)

Ice ages are the greatest natural climate changes in recent geological times. Their rise and fall are caused by slight changes in the Earth's orbit around the sun due to the influence of the other planets. New research from the Niels Bohr Institute indicates that there can be changes in the CO2 levels in the atmosphere that suddenly reach a critical turning point and with that trigger the dramatic climate changes. The results are published in the the American journal Paleoceanography. ...> Full Article

Fingerprinting slow earthquakes (4/26/2009)

The most powerful earthquakes happen at the junction of two converging tectonic plates, where one plate is sliding (or subducting) beneath the other. Now a team of researchers, led by Teh-Ru Alex Song of the Carnegie Institution, has found that an anomalous layer at the top of a subducting plate coincides with the locations of slow earthquakes and non-volcanic tremors. Such a layer in similar settings elsewhere could point to other regions of slow quakes. ...> Full Article

Ancient Greenland methane study good news for planet (4/25/2009)

An analysis of ancient Greenland ice suggests a spike in the greenhouse gas methane about 11,600 years ago originated from wetlands rather than the ocean floor or from permafrost, a finding that is good news according to the University of Colorado at Boulder scientist who led the study. ...> Full Article

Measuring snow with a bucket, a windmill, and the sun? (4/24/2009)

In Maine, government scientists have figured out how to measure snowfall in remote areas with a bucket, a small windmill, and the sun -- all the while saving money, energy, and, ultimately helping to save lives. ...> Full Article

Increasing Antarctic sea ice extent linked to the ozone hole (4/23/2009)

Increased growth in Antarctic sea ice during the past 30 years is a result of changing weather patterns caused by the ozone hole according to new research published this week. ...> Full Article

As world warms, water levels dropping in major rivers (4/22/2009)

Rivers in some of the world's most populous regions are losing water, according to a comprehensive study of global stream flows. ...> Full Article

Clouds: Lighter than air but laden with lead (4/21/2009)

Atmospheric lead causes clouds to form more easily, could change pattern of rain and snow ...> Full Article

Origins of sulfur in rocks tells early oxygen story (4/18/2009)

Sedimentary rocks created more than 2.4 billion years ago sometimes have an unusual sulfur isotope composition thought to be caused by the action of ultra violet light on volcanically produced sulfur dioxide in an oxygen poor atmosphere. Now a team of geochemists can show an alternative origin for this isotopic composition that may point to an early, oxygen-rich atmosphere. ...> Full Article

Megadroughts in sub-Saharan Africa normal for the region (4/17/2009)

Devastating droughts worse than the infamous Sahel drought are part of the normal climate regime for sub-Saharan West Africa, according to new research. Scientists have developed the first almost year-by-year record of the last 3,000 years of West Africa's climate. In that period, catastrophic droughts occurred every 30 to 65 years, and the pattern can be expected to continue in the future, the team reports in the April 17 issue of the journal Science. ...> Full Article

Satellites show how Earth moved during Italy quake (4/16/2009)

Studying satellite radar data from ESA's Envisat and the Italian Space Agency's COSMO-SkyMed, scientists have begun analysing the movement of Earth during and after the 6.3 earthquake that shook the medieval town of L'Aquila in central Italy on April 6, 2009. ...> Full Article

Study uncovers tectonic events behind earthquake that killed 595 in Peru (4/15/2009)

In a study published in the Geophysical Journal International, scientists from the University of Miami's Rosenstiel School of Marine and Atmospheric Science, in collaboration with scientists from the University of Oxford have analyzed data on this earthquake and its impact on regional topography. Using InSAR-based geodetic data and teleseismic data, the scientists were able to use satellite images to identify details of this major plate boundary event. ...> Full Article

How do they spread? (4/14/2009)

Propagation of earthquake waves within the Earth is not uniform. Experiments indicate that the velocity of shear waves in Earth's lower mantle between 660 and 2900 km depth is strongly dependent on the orientation of ferropericlase. ...> Full Article

California's central coast earthquake hazards: New information about recently identified faults (4/13/2009)

Seismologists are re-evaluating the earthquake potential of the Central Coast, a very complex tectonic region located west of the San Andreas Fault, between Monterey Bay and the Western Transverse Ranges. This area of increasing population growth ranks as one of the top 40 US metropolitan areas with significant earthquake risk. ...> Full Article

Monitoring Yellowstone earthquake swarms (4/13/2009)

Analysis of the recent swarm suggests epicenters migrated north over the 12-day period and maximum hypocenter depths abruptly shallowed from 12 km to 3 km depth at the time of rapid cessation of activity on Jan. 7. ...> Full Article

Study compares sound from exploding volcanoes with jet engines (4/12/2009)

New Scripps study of low-frequency sound from Mount St. Helens and Tungurahua volcanoes provides explanation for how the large-amplitude signals from eruptions are produced ...> Full Article

Earth under global cooling (4/11/2009)

Thirty-four-million years ago, Earth changed profoundly. What happened, and how were Earth's animals, plants, oceans, and climate affected? Focusing on the end of the Eocene epoch and the Eocene-Oligocene transition, a critical but very brief interval in Earth's history, GSA's latest Special Paper provides new answers to these questions. ...> Full Article

Solomon Islands earthquake sheds light on enhanced tsunami risk (4/10/2009)

The 2007 Solomon Island earthquake may point to previously unknown increased earthquake and tsunami risks because of the unusual tectonic plate geography and the sudden change in direction of the earthquake, according to geoscientists. ...> Full Article

Did a nickel famine trigger the 'Great Oxidation Event'? (4/10/2009)

The Earth's original atmosphere held very little oxygen. This began to change around 2.4 billion years ago when oxygen levels increased dramatically during what scientists call the "Great Oxidation Event." The cause of this event has puzzled scientists, but researchers writing in Nature have found indications in ancient sedimentary rocks that it may have been linked to a drop in the level of dissolved nickel in seawater. ...> Full Article

Scientists pierce veil of clouds to 'see' lightning inside a volcanic plume (4/9/2009)

Researchers hit the jackpot in late March, when, for the first time, they began recording data on lightning in a volcanic eruption -- right from the start of the eruption. ...> Full Article

Dust plays larger than expected role in determining Atlantic temperature (4/7/2009)

The recent warming trend in the Atlantic Ocean is largely due to reductions in airborne dust and volcanic emissions during the past 30 years, according to a new study. ...> Full Article

Bent tectonics: How Hawaii was bumped off (4/6/2009)

Volcanoes and islands are dotted along the Hawaii-Emperor seamount chain like pearls on a necklace. The sharp bend in the middle of this formation is due to a migrating hotspot, a submerged volcano that produced the Hawaii-Emperor chain millions of years ago. ...> Full Article

Simulations and ancient magnetism suggest mantle plumes may bend deep beneath Earth's crust (4/5/2009)

Computer simulations, paleomagnetism and plate motion histories described in today's issue of Science reveal how hotspots, centers of erupting magma that sit atop columns of hot mantle that were once thought to remain firmly fixed in place, in fact move beneath Earth's crust. ...> Full Article

Straw bale house survives violent shaking at earthquake lab (4/4/2009)

It huffed and puffed, but the 82-ton-force, earthquake-simulation shake table could not knock down the straw house designed and built by University of Nevada, Reno alumna and civil engineer Darcey Donovan. The full-scale, 14-by-14-foot straw house, complete with gravel foundation and clay plaster walls, the way she builds them in Pakistan, was subjected to 200 percent more acceleration/shaking than was recorded at the 1994 Northridge, Calif. earthquake, the largest measured ground acceleration in the world. ...> Full Article

Ice-free Arctic summers likely sooner than expected (4/4/2009)

Summers in the Arctic may be ice-free in as few as 30 years, not at the end of the century as previously expected. The updated forecast is the result of a new analysis of computer models coupled with the most recent summer ice measurements. ...> Full Article

Technique measures heat transport in the Earth's crust (4/3/2009)

Putting a new spin on an old technique, Anne M. Hofmeister, Ph.D., research professor of earth and planetary sciences at Washington University in St. Louis, has revolutionized scientists' understanding of heat transport in the Earth's crust, the outermost solid shell of our planet. ...> Full Article

More than 500 seismologists to meet April 8-10 in Monterey, Calif. (4/2/2009)

Seismologists from around the world will gather at the 2009 Annual Meeting of the Seismological Society of America. ...> Full Article