Japanese Scientists Detect Rare 'Weather Bomb' That Could Unlock Secrets of Earth's Interior
A team of scientists from Japan has, for the first time, detected a rare phenomenon called the "weather bomb." This deep-Earth tremors, caused by an elusive kind of seismic wave called the S wave, could hold the key to the secrets of the Earth's interior.
According to the study published in the journal Science, the S waves were detected off the coast of Greeland in the North Atlantic Ocean and have a velocity of 20 to 22.2 kilometer per second. The scientists detected these S waves using seismic sensors.
"Using a seismic array in Japan, we observed both P and S wave microseisms excited by a severe distant storm in the Atlantic Ocean," said Kiwamu Nishida and Royta Takagi of the study. "The seismic energy traveling from weather bombs through the Earth appears to be capable of illuminating the many dark patches of Earth's interior."
Sputnik News notes that in order to track these deep-Earth tremors, the researchers had to analyze different data from 202 extra-sensitive seismic stations located in Japan.
S waves are extremely rare to be detected because they usually fade in the planet's seismic noise. Different from P waves, which could be detected by animals before an impending earthquake, S waves travel slower, making it harder to track their source. During an earthquake, these vibrations from the S waves arrive after P waves and cause stronger tremors than the latter, BBC reports.
"Most of what we know about the internal structure of the Earth has been determined from studying the way earthquake waves propagate, through the lower crust and the mantle and the core," Peter Bromirski of the University of California San Diego told Science in Action on the BBC World Service.
"In order to do that, you need to have a source that can generate a signal that propagates to your seismic stations. For some reason there are very few earthquakes in the mid Pacific... so we don't have any sources there," he added.
This breakthrough detection could help seismologists and other experts to have a clearer picture of the structure of the Earth below the Pacific.