Scientists have long known earthquakes can cause the Earth to vibrate for extended periods of time. However, in 1998 a research team found the Earth also constantly generates a low-frequency vibrational signal in the absence of earthquakes.
Since then, seismologists have proposed different theories to explain the existence of this continuous vibration, from atmospheric disturbances to ocean waves moving over the sea floor. They’ve also measured the vibration using seismometers on land, but had not yet successfully measured it at the sea floor, which could help scientists better quantify the sources of the vibrations.
Now, using seismic instruments on the bottom of the ocean, researchers have successfully quantified Earth’s vibrational “hum”. A new study published in Geophysical Research Letters, a journal of the American Geophysical Union, determined at the ocean bottom the frequencies at which the Earth naturally vibrates, and confirmed the viability of using ocean instruments to study the hum.
Capturing the hum at the ocean bottom could provide new insights into the source magnitude, according to Martha Deen, a geophysicist at the Paris Institute of Earth Physics in Paris, France and lead author of the new study.
Additionally, the new findings could be used to map the interior of Earth with more detail and accuracy. Including the hum from seismometers on the ocean sea floor can give a better overall picture than using land seismometers alone by increasing data coverage in large uncovered areas, Deen said.
Read more : Phys.org