November 26, 2012
Scientists Use TNT To Predict Volcanic Explosions
[WATCH VIDEO: Using TNT To Understand Volcanoes]
Lee Rannals for redOrbit.com — Your Universe OnlineResearchers chucked some TNT into the Earth in order to study maar craters and help predict the next big volcano.
University at Buffalo scientists reported in the journal Geophysical Research Letters that they performed experiments to help examine maar carters, which resemble the bowl-like cavities formed by meteorites.
By measuring meteorite impacts, scientists are able to determine when they struck, how large they were and the angle at which they approach Earth. These techniques could also be used to gain a better understanding of volcanoes.
Maar craters form when fissures of magma beneath Earth's surface meet up with groundwater, causing volcanic explosions. The possibility of multiple explosions at varying depths has led most scientists to believe that measuring a maar's size is not the best way to gauge the energy of individual explosions.
The researchers in the latest study found that by examining a maar's shape and the distance it ejects magma, ash and other debris, can lead to a more accurate barometer of the eruption's force.
Greg A. Valentine said that the findings are important because they could assist scientists in estimating how big future volcano eruptions might be.
"It's something that, up until this point, had only been suspected," Valentine, a professor of geology and lead author of the paper, said in a statement. "The simulations we did prove that crater diameter is not a good indicator of explosion energy for these volcanoes."
For the research, the scientists conducted a series of experiments last summer at a test site in Ashford, New York. They built three test beds of gravel, limestone and asphalt.
During the first experiment, the team set up one charge of TNT and plastic explosives. In subsequent experiments, the charge was divided into three parts and detonated individually at different depths.
They found that the final dimensions of each crater were about the same. This find matters because it shows that it is easy to overestimate the energy of explosions if one assumes the crater comes from one blast, according to Valentine.
The first charge saw debris fly more than 50 feet from the crater. During the subsequent experiments simulating blasts further underground, debris mostly went up in the air and fell back into the crater around its rim. This forced dusty gas up into the surrounding air.
Valentine said that although the experiments provided valuable information, they were similar to just a practice run. He said more detailed experiments are planned for the near future.