On 17 June 2017, one of the tallest tsunamis in recorded history struck the small fishing village of Nuugaatsiaq in northwestern Greenland, washing away 11 houses and leaving four people dead. The 100-meter wave surprised scientists because earthquakes—which typically drive such waves—are not common in that area.
Soon after the event, researchers tied the tsunami to a large landslide that had plunged into a nearby fjord, releasing as much energy as a magnitude 4.1 earthquake. Now a new study identifies patterns in seismic data from hours before the slide occurred, which might be helpful in predicting future landslides in glacial regions.
Days or hours before a large earthquake, scientists can often use seismic signals generated by slippage along faults in Earth’s crust to predict the size and severity of the coming quake. In the new study, Poli analyzed seismic data recorded about 30 kilometers from where the mass of rocks and dirt fell into the fjord. In the hours before the slide, he found repetitive waves of energy, likely caused by a series of ruptures in the brittle rock, similar to those that happen before earthquakes.
The pattern the author observed fits with a growing body of evidence that the velocity of slippage along weak faults increases exponentially before materials such as Earth’s crust or rocks and dirt in a landslide fail. If the physics underlying earthquakes and landslides are indeed similar, as the study suggests, scientists may be able to develop better detection systems for future slides. As the climate warms, causing more landslides in glacial regions, such predictions could help communities better prepare for disaster. (Geophysical Research Letters, https://doi.org/10.1002/2017GL075039, 2017)
—Emily Underwood, Freelance Writer
from Eos https://eos.org/research-spotlights/what-precursors-foretold-greenlands-recent-100-meter-tsunami?utm_source=rss&utm_medium=rss&utm_content=what-precursors-foretold-greenlands-recent-100-meter-tsunami
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