Mount Nyiragongo, an active volcano on the eastern border of the Democratic Republic of Congo, erupted for six hours last May. Staff at Goma . Volcano Observatory unpredictable Natural disasters and earthquakes ensued, forcing evacuations from the nearby city of Goma and resulting in hundreds of deaths and injuries. This event has volcanologists and other scientists around the world on high alert – if we can’t predict exactly when a volcano might erupt, how can we? Can we make sure we can protect people and get them to safety in time?
Turns out, there to be Observable warning signs that we might have recognized, if we had searched hard enough. In a new study published Wednesday in Nature, an international team of volcanologists tasked with investigating the seismic signals of the Nyiragongo eruption discovered that there was writing on the wall about 40 minutes before the eruption that had never been seen before. observed. The new findings tell us what caused the eruption, why it happened with little warning, and how we can forecast such deadly events in the future.
A view of the lava lake inside the Nyiragongo crater, home to the largest lava lake on Earth. “
Guenter Guni / Getty
“The onset of volcanic eruptions is often heralded by changes in observable features such as seismic activity, gasification, and the shape of the volcano,” said US geologist. About the volcano Emily Montgomery-Brown wrote in an attached comment In Nature. “However, that is not the case [May 22, 2021]when Mount Nyiragongo in the Democratic Republic of the Congo erupted. “
The devastation in Goma is triggered by magma plates known as dikes that run beneath the surface of the ground. Typically, Montgomery-Brown wrote, volcanic dykes require force to spread – that is, scientists can observe some warning signs produced by phenomena such as tectonic plate displacement. But that is not the case in Nyiragongo; Instead, the study’s authors suggest that what happens instead is a passive force caused by the main part of the volcano spreading out due to its own weight. Also unusual is how close the magma plates are to the surface, allowing the dike to easily penetrate the surface and cause earthquakes.
Already close to the surface, the magma only has to propagate in one direction for a short distance before erupting, leaving little time to detect and interpret the associated signals, the authors write in the study. . They added that that 40-minute period was “extremely short, but it would allow some risk-mitigation actions” not to be taken.
The team of volcanologists investigated several aspects of the eruption, including by surveying local residents about how the disaster affected the city’s infrastructure and people; analyze ash plume data collected from space to infer volcanic activity; and modeled how the dike spreads out from the main part of the volcano.
However, it remains unclear how useful analyzes focusing on passive dikes would be for other volcanic eruptions, Montgomery-Brown writes. Equally important to disaster preparedness is “building effective communication lines, developing public awareness of risks, and reducing exposure to unexpected hazards.” , she wrote.
If we can reinforce other considerations, we can develop some more plans that can save lives from disasters like this in the future. Less than an hour may not be a lot of time to prepare, but it can be the difference between life and death if we can plan our preparation accordingly.
