Monthly Archives: August 2011

Japan’s Natural Hazards

Lamont-Doherty experts

discuss science behind

Japan’s earthquakes

First published on the Earth Institute and Lamont-Doherty web sites on March 30, 2011.

The Great Japan Earthquake: Where Did Scientists Go Wrong? from Earth Institute on Vimeo.

In the two and a half weeks since a massive earthquake struck Japan, scientists from the Lamont-Doherty Earth Observatory have been immersed in both studying the quake, and reaching out to the media and other organizations to explain what happened. Other Earth Institute experts have added their voices to the public conversation about natural hazards, preparedness and nuclear power.

Can we ever be prepared enough for such events? The Japanese were as experienced as any people on the planet when it comes to dealing with earthquakes. Yet they were caught off-guard by a once-in-a-thousand-year event. In a matter of hours, that same event washed ashore on the U.S. West Coast, a relatively minor reminder that we, too, may not always be ready when the power of natural forces takes charge.
The jolt in Japan stunned even scientists who’ve studied earthquakes all their lives. Chris Scholz, a Lamont-Doherty Earth Observatory professor with decades of experience looking at how earthquakes work, said he had thought a 9.0 magnitude quake like the one that struck near Sendai, Japan, was “impossible” in that area (see video). But it turns out the last comparable earthquake shook the same region in the year 869 and pushed a tsunami miles into the interior. Scientists were humbled by the realization that they simply had not looked back far enough to gauge the probability of such a huge event.

Leave a comment

Filed under Science, Stories

Some Antarctic Ice is Forming from Bottom

First published March 2, 2011, on the Lamont-Doherty Earth Observatory web site, http://www.ldeo.columbia.edu.

The radar image shows the Gamburtsev Mountains, at bottom of the image, overlain by the ice sheet, which has been deformed by a bulge of refrozen ice (center). (Courtesy Bell et al., 2011)

Scientists working in the remotest part of Antarctica have discovered that liquid water locked deep under the continent’s coat of ice regularly thaws and refreezes to the bottom, creating as much as half the thickness of the ice in places, and actively modifying its structure. The finding, which turns common perceptions of glacial formation upside down, could reshape scientists’ understanding of how the ice sheet expands and moves, and how it might react to warming climate, they say. The study appears in this week’s early online edition of the leading journal Science; it is part of a six-nation study of the invisible Gamburtsev Mountains, which lie buried under as much as two miles of ice.

Ice sheets are well known to grow from the top as snow falls and builds up annual layers over thousands of years, but scientists until recently have known little about the processes going on far below. In 2006, researchers in the current study showed that lakes of liquid water underlie widespread parts of Antarctica. In 2008-2009, they mounted an expedition using geophysical instruments to create 3-D images of the Gamburtsevs, a range larger than the European Alps. The expedition also made detailed images of the overlying ice, and subglacial water.

Leave a comment

Filed under Climate, Environment, Science, Stories

As the Dead Sea Dries, Drilling Shows It’s Not the First Time

First published Dec. 22, 2010, on the Lamont-Doherty Earth Observatory web site: www.ldeo.columbia.edu.

Sediment cores taken from the Dead Sea indicate the area has dried up almost completely, probably in conjunction with the recession of glaciers. In the middle of a relatively dry period, the lake is under additional stress now from human consumption. (Photo: Adi Torfstein)

In the first project of its kind, scientists are drilling deep into the bed of the fast-shrinking Dead Sea, searching for clues to past climate changes and other events that may have affected human history back through Biblical times and before. In one early discovery, they have found that the sea has come and gone in the past—a revelation with powerful implications for the current Mideast.

Spanning Israel and Jordan, the inland Dead Sea is earth’s lowest-lying spot on land, with shores some 1,400 feet below ocean level, and hyper-salty waters going down another 1,200 feet or more. Beneath  lie deep deposits of salts and sediments fed by the Jordan River drainage. The drilling, some 10 years in the making, is being conducted by investigators from Israel, the United States, Germany, Japan, Switzerland and Norway.

Leave a comment

Filed under Climate, Environment, Science, Stories