Press Trust of IndiaSeptember 21, 2020 11:47:44 AM
Scientists have developed a novel method to determine how quickly the Indian Ocean is warming by analyzing the sound of earthquakes on the sea floor. This could lead to a relatively inexpensive technique for monitoring water temperatures in all oceans.
According to researchers, including those from the California Institute of Technology (Caltech) in the US, up to 95 percent of the additional heat that greenhouse gases like carbon dioxide store on the earth is stored in the world̵
Published in the current study in the journal scienceScientists used existing seismic monitoring equipment as well as historical earthquake data to determine how much the ocean’s temperature has changed and continues to change, even at depths usually beyond the reach of conventional tools.
They assessed a 3,000-kilometer section in the equatorial East Indian Ocean and found temperature fluctuations between 2005 and 2016 with a decadal warming trend that “significantly exceeds previous estimates”. According to one estimate, the oceans could warm up by almost 70 percent more than assumed. However, they cautioned against drawing immediate conclusions as more data needs to be collected and analyzed.
Jorn Callies, co-author of Caltech’s study, found that the method monitors underwater quake sounds, which are strong and travel long distances through the ocean without significantly weakening. The researchers explained that during an earthquake under the ocean, most of its energy flows through the earth, but some of that energy is carried into the water as sound.
They said these sound waves propagate outward from the epicenter of the quake, just like seismic waves that move through the ground, but added that the sound moves at a much slower rate. The study found that the bumps arrive at a seismic monitoring station first, followed by the sound waves, which appear as a secondary signal of the same event. According to the researchers, this effect is similar to how you often see lightning in a flash before you hear its thunder.