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A nuclear accident is defined by the International Atomic Energy Agency (IAEA) as an incident in which people died or property damage topped $50,000. In 1990, IAEA introduced the International Nuclear and Radiological Event Scale (INES) to rate and rank nuclear accidents. INES is a logarithmic scale that consists of seven levels: 0 (Deviation, no safety significance), 1 (Anomaly), 2 (Incident), 3 (Serious incident), 4 (Accident with local consequences), 5 (Accident with wider consequences), 6 (Serious accident) and 7 (Major accident).

The growing interest in coal fires has led to the largest collection of peer-reviewed publications about this topic ever undertaken for publication, which includes the work of scientists and engineers around the world interested in peat, the precursor of coal, and peat fires. This project has resulted in a four-volume book, entitled “Coal and Peat Fires: A Global Perspective,” to be published later this year by Elsevier. It will include an interactive online world map of coal and peat fires.

Currently (and historically), most people who deal with underground coal fires and gob fires are employed by government agencies, mining and engineering companies, and firefighting agencies. Today, as in the past, these institutions undertake various responsibilities that include recording the location of coal fires, tracking their progression, and extinguishing the most problematic ones, if physically and economically feasible.

Moment of impact: As the asteroid hits the ground with a velocity of several tens of kilometers per second, a shock wave is generated that penetrates radially into the ground and compresses the rocks.

Christian Koeberl, University of Vienna

Although our final results won’t begin to be published until early next year, our team met in May to review all the data we had collected so far.

We had drilled several types of cores. Our initial pilot cores, taken in 1998 and 2003, provided proof of concept, demonstrating the importance of these cores as a climate record, as they contain climate data that extend back in time 300,000 years — roughly three times longer back in time than the oldest portions of the Greenland ice core records.

The last time Chile experienced an earthquake larger than magnitude 8.8 was on May 22, 1960, when a magnitude-9.5 earthquake rocked the South American nation, killing 1,655 people and leaving 2 million people homeless, according to the U.S. Geological Survey. It was the largest earthquake in recorded history. Prior to that, a magnitude-8.5 quake struck central Chile near its border with Argentina on Nov. 11, 1922 — the 13th-largest earthquake on record.

Geotimes magazine became EARTH magazine on Sept. 1, 2008!

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“The word ‘xeriscape’ brings to mind a lot of pebbles with cacti,” says Janet Ward, public relations manager for the City of Atlanta’s Department of Watershed Management. “That’s not what xeriscaping is, but that’s what people think it is.” Xeriscaping is simply minimum-water landscaping. It can involve everything from stones and cacti, to sedums, drought-tolerant plants and native bushes. Indeed, a glimpse into yards in Denver, Colo., often reveals fiery blanketflowers, magenta poppy mallows and sky-blue forget-me-nots.

In August, the Wall Street Journal reported that a little-known chemical was playing a big role in the Cash for Clunkers program. The federal government required dealerships to pour sodium silicate, or liquid glass, into the engines of the traded-in clunkers. The solution destroys the engine, ensuring that the old cars and trucks never end up back on the road. The Journal noted that chemical companies couldn’t keep up with the sodium silicate orders that were pouring in.

David Harwood’s field geology course gives future teachers an introduction to several of geology’s most fundamental principles, including the stratigraphic basics described by Nicholas Steno in 1669. Go to the head of the class with this quick primer.

Ardipithecus ramidus was a hominid that lived in Ethiopia’s Afar region 4.4 million years ago. After spending more than a decade studying the species, scientists can now provide a sketch of what the hominid looked like:

Brain: Ardipithecus had a brain size similar to that of a female chimpanzee, about 300 to 350 cubic centimeters.

Stature: Standing 120 centimeters tall and weighing 50 kilograms, Ardipithecus was about the size of a chimpanzee.

At 4.4 million years old, Ardipithecus ramidus is not the oldest known hominid. In 2002, scientists announced they had discovered a hominid skull from the Sahel region of Chad. Named Sahelanthropus tchadensis, the species dates to about 7 million years ago. And a few years earlier, scientists had announced the discovery of several hominid fossils, including a thigh bone, in Kenya that dated to about 6 million years ago. They named the species Orrorin tugenensis.

Volcanologists have long been assessing the impacts of volcanic ash and gases on the environment and human health. This effort began in earnest when volcanologists at the U.S. Geological Survey undertook extensive studies of the environmental characteristics of ash from the 1980 Mount St. Helens eruptions. These studies included water leach tests showing that rain falling onto fresh ash can be quite acidic due to the liberation of acidic gas species that condense onto ash particles in the eruption cloud.

Although Earth’s magnetic field currently points toward the North Pole, the planet’s magnetic dipole flips direction every few hundred thousand years or so. Engebretson tracked the last 85 million years of these magnetic reversals, with higher pitches representing shorter polarities (a period of time when the direction of the magnetic field stays the same), and lower pitches longer ones.

Earth experiences small, millimeter-sized tides, called Earth tides. Using a dataset from NASA’s Jet Propulsion Laboratory in California from A.D. 1600 to A.D. 2200, Engebretson calculated the net gravitational force of the sun and the moon at particular intervals and then mapped them onto the A major scale.