麻豆传媒

AS PEOPLE in Nevada are gearing up to oppose the US Department of Energy鈥檚 plans for a nuclear waste dump at Yucca Mountain, a local scientist has come up with more ammunition for the protesters.

Eugene Smith, a geologist at the University of Nevada at Las Vegas, says the site of the proposed dump lies along a line of old volcanoes with a troubling history of eruptions. Some erupt more often than official estimates suggest, Smith claims, and from time to time the whole area goes through periods of increased volcanic activity.

The flaw in the Department of Energy鈥檚 assessments, says Smith, is that it has been looking only at the volcanoes nearest Yucca Mountain. This region, known as Crater Flat, is relatively docile, with 3.7 to 12 eruptions per million years. But there is another group of volcanoes 100 kilometres to the north in an area called the Lunar Crater field, which tend to erupt more often, around 11 to 15 times per million years.

That Yucca mountain lies on the line between these two volcanic fields is worrying enough for a project that is supposed to safely store nuclear waste for at least 10,000 years, but Smith says that there are other reasons to worry. He says that that there are periods when both Crater Flat and Lunar Crater are more likely to experience eruptions. Whether the region is about to enter one of these episodes is anyone鈥檚 guess, says Smith. To find out, he suggests exploring how the two crater fields might be connected and what causes them to erupt in the first place. Smith suggests that eruptions may be triggered by a buoyant hot spot in the mantle. But no one knows for sure, he points out, and that鈥檚 why DOE should proceed with caution.

Volcanoes are not the only geological hazard for the Yucca mountain project. Earthquakes and rising groundwater could also lead to releases of radioactive waste. But none of these, so far, has had any apparent impact on the political process.