New Zealand: An island nation in the southwest Pacific Ocean, roughly 1,500 kilometers (some 900 miles) east of Australia. Infrasound: Sound waves with frequencies below the lower limit of human hearing. People who work in this field are known as geologists. Geologic: An adjective that refers to things that are related to Earth’s physical structure and substance, its history and the processes that act on it. It is the opposite of an artificial setting, such as a research laboratory. Also a term to describe a real-world environment in which some research is conducted, such as at sea, in a forest, on a mountaintop or on a city street. This happens on Enceladus, a moon of Saturn that is covered in ice.įactor: Something that plays a role in a particular condition or event a contributor.įield: An area of study, as in: Her field of research is biology. In colder parts of the solar system, eruptions often involve liquid water spraying out through cracks in an icy crust. Volcanic eruptions on Earth usually send hot lava, hot gases or ash into the air and across surrounding land. In water, this may create a whirlpool.Įruption: (in geoscience) The sudden bursting or spraying of hot material from deep inside a planet or moon and out through its surface. “It’s a big wake-up call.”Īsh: (in geology) Small, lightweight fragments of rock and glass spewed by volcanic eruptions.Īverage: (in science) A term for the arithmetic mean, which is the sum of a group of numbers that is then divided by the size of the group.Ĭolleague: Someone who works with another a co-worker or team member.Įddy: A circular motion that develops in some liquid or gas and that moves in a direction opposite to the main current. Many hazard assessments are probably underestimating the destructiveness of pyroclastic flows by a lot, Lube says. Sometimes the pulses smashed more than three times as hard as the average pressure estimates. These pulses would successively damage obstacles like blows from a jackhammer, Lube says. This happened as volcanic particles clustered into cascading waves and trains of rolling eddies. To the researchers’ surprise, flow pressures rose and fell in a rhythmic pattern. Analyze This: Can you outrun these geological disasters? They engulfed a set of infrasound sensors. That’s when pyroclastic flows burst from the Whakaari volcano in New Zealand. The researchers also analyzed the first measurements of pressures in natural flows. That let the team calculate pressures inside the flows. These included particle velocities and temperatures. So they reproduced smaller versions of the flows in experiments. Lube and his colleagues wanted to directly study the inner workings of these flows. Those are based on studies of geologic deposits left by past flows. Researchers often have to estimate average obstacle-smashing pressures in the flows. Because these flows are so violent, studying them directly can be hard. That’s due in part to the pressures they generate. Pyroclastic flows are the deadliest volcanic hazard. But, he says, the pressures might be so strong “they knock down the walls of the building.” Explainer: The volcano basics A conventional hazard assessment might suggest a certain flow will only burst windows. He’s a volcanologist at Massey University. “It’s not a small difference,” says Gert Lube. Researchers shared their new finding this past December 15 in Nature Communications. Those pressures can be far stronger, and more destructive, than hazard assessments typically assume. Within these slides, pulses of high pressure form. Those pulses are the result of turbulence, lab and field measurements now show. Known as pyroclastic flows, they may be even more dangerous than scientists had suspected. Avalanches of ash, gas and rock can cascade downhill during volcanic eruptions.
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