For over a century scientists have studied the warning signs of impending volcanic eruptions, but accurate predictions of these explosions are often imprecise.

A new study on volcanoes published Sept. 5 in the online journal Nature Geoscience, put out by a group of scientists from Europe and Yale, identifies key signals of an imminent eruption. The study used gas flow measurements from within volcanoes to identify different types of oscillations that the volcano undergoes prior to eruption, which are key in predicting when the eruption will happen, said study senior author and Yale geophysics professor David Bercovici.

“Separating the dangerous rumbles from the everyday rumbles is what this new model is all about,” Yale professor of geology and geophysics Jeffery Park said.

According to Park, all the big volcano eruptions in the past 100 years exhibited warning signs, but eruption false alarms do not receive as much attention. This latest study aimed to use scientific measurements to create a model to bring researchers ever closer to pinpointing when an eruption will occur.

To monitor volcanic activity, volcanological observatories measure precursors, or pre-eruption activity such as tremors and gas flow oscillations. In addition to changes in gas release, there are more short-term tremors that last for hours or minutes before an eruption, as well as slow, long-term repeated oscillations in ground swelling and collapse that occur over several days or even weeks.

Bercovici’s study deals with monitoring the long-term tremors, which are vital to understanding whether an eruption is imminent.

Since not all volcanoes undergo tremors, the research team focused on studying active volcanoes, which are more likely to erupt and are considered more dangerous, Bercovici said.

“Active volcanoes remain a major hazard for populations that live in regions with ongoing activity,” geology and geophysics assistant professor Maureen Long said. She said scientists can learn as much as possible about the physical processes associated with eruptions to implement monitoring systems that can help provide warnings to populations that might be affected.

Though models — especially those predicting massive geophysical events like volcanic eruptions — are prone to innacuracy, Bercovici said these studies allow scientists to improve on past models of prediction.

“In the real world, sometimes official warnings are ‘false alarms”’ that can begrudge the public perception of science, but the public needs to realize that science by its very nature is uncertain — only religion is 100 percent sure of anything,” geology and geophysics professor David Evans said. “Scientific assessments of natural hazards, including the prospects of early warning within hours to days before a volcanic eruption, can save many lives if authorities and the public are well enough informed to receive that advice.”

The lead author of the study is Chloé Michaut of the Institut de Physique du Globe de Paris, a former Yale postdoctoral student under Bercovici. The study’s other senior authors include Yanick Ricard of Université Lyon and R. Steven J. Sparks of University of Bristol.

The biggest volcanic eruption ever recorded by humans was the explosion of Mount Tambora on Sumbawa Island, Indonesia, in 1815.