using sound waves from underwater earthquakes to monitor warming oceans

Es­ti­mated reading time is 1 minute.

OUR OCEANS RE­MAIN MYS­TE­RIOUS AND ALIEN but we are learning more about it every day—sometimes, out of ne­ces­sity. Such as the need to un­der­stand changes in the tem­per­a­tures of the wa­ters as a po­ten­tial re­flec­tion of global cli­mate change. In an ar­ticle ti­tled “Un­der­water earth­quakes’ sound waves re­veal changes in ocean warming” by for Sci­ence News (Sep­tember 17, 2020).

The ar­ti­cle’s sub-title is, “Seismic ocean ther­mom­etry could im­prove tem­per­a­ture mon­i­toring in the vast seas.” While depth and tem­per­a­ture af­fect sound trav­eling through water, es­sen­tially sound waves travel ap­prox­i­mately four times faster and four times far­ther in water than they do in the air. This is why whales can com­mu­ni­cate over vast dis­tances in the oceans. Ac­cording to Gramling:

“As green­house gas emis­sions warm the planet, the ocean is ab­sorbing vast amounts of that heat. To mon­itor the change, a global fleet of about 4,000 de­vices called Argo floats is col­lecting tem­per­a­ture data from the ocean’s upper 2,000 me­ters. But that data col­lec­tion is scanty in some re­gions, in­cluding deeper reaches of the ocean and areas under sea ice.

So Wenbo Wu, a seis­mol­o­gist at Cal­tech, and col­leagues are resur­facing a decades-old idea: using the speed of sound in sea­water to es­ti­mate ocean tem­per­a­tures. Wu’s team tested a way to use earthquake-generated sound waves trav­eling across the East In­dian Ocean to es­ti­mate tem­per­a­ture changes in those wa­ters from 2005 to 2016.

Com­paring that data with sim­ilar in­for­ma­tion from Argo floats and com­puter models showed that the new re­sults matched well. That finding sug­gests that the tech­nique, dubbed seismic ocean ther­mom­etry, holds promise for tracking the im­pact of cli­mate change on less well-studied ocean regions.”

To read the ar­ticle in its en­tirety, click HERE.


Underwater Earthquakes: ocean waves

FEA­TURED IMAGE: The photo at the top of this page ac­com­pa­nied the Sci­ence News ar­ticle. The cap­tion: “Sound waves pro­duced by the rum­bles of un­dersea quakes pro­vide a new way to study how cli­mate change is warming the oceans.” The photo cour­tesy of Silas Baisch for Unsplash.


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