Every 26 seconds, Earth’s ‘mysterious heartbeat’ repeats; scientists still don’t know why

Visualise a heartbeat deep down under the Earth; soft, periodic, and undetectable to the human eye. Every 26 seconds, a faint seismic pulse emanates from deep within the Earth's crust. It does not level cities or lead to harm, but these vibrations continue unabated, exciting seismologists and geophysicists around the world.The

Earth’s 26-second pulse

may not be a harbinger of disaster, but it is a compelling reminder of the planet’s internal rhythms; rhythms we’re only beginning to understand. As technology evolves and data becomes more refined, future research may finally explain the pulse’s origin. Until then, it remains a quiet mystery repeating without fail, deep under the sea and beneath our feet.

How Earth’s 26-second pulse was first discovered in the 1960s

According to the Discover Magazine reports, Earth's silent pulse history began over 60 years ago. In the early 1960s, a geophysicist named Jack Oliver, with the crude seismic equipment available at that time, noticed an unusual rhythmic signal in the seismograms. He determined its origin to be in the equatorial Atlantic Ocean, where he discovered it appeared to be periodic, becoming larger at specific times of the year.

Even though his revolutionary find, the limitations of seismic technology during that era implied the signal could not be entirely verified. It was a scientific curiosity, nearly lost for years.

University of Colorado study confirms Earth’s rhythmic tremor

In 2005, researchers at the University of Colorado Boulder reignited interest in this peculiar phenomenon. Seismologist Mike Ritzwoller and his colleagues, with more sensitive and state-of-the-art equipment, detected the same signal occurring exactly every 26 seconds. They were successful in identifying its source as the Gulf of Guinea, off the coast of west Africa.“We saw something strange, consistent, and persistent,” Ritzwoller said, emphasizing the unique nature of this pulse. Unlike typical seismic activity, which is irregular and event-driven, this tremor was incredibly uniform and appeared unrelated to earthquakes or tectonic movement.

Scientists view on the origin of the pulse

Scientists have proposed two major hypotheses to explain the origin of the pulse:

One of the more well-supported ideas is that ongoing vibrations from ocean waves beating the continental shelf would create such vibrations. The theory suggests that when big waves hit the shallow underwater edges of continents, they apply pressure that generates weak seismic signals within the Earth's crust. It is similar to tapping on one end of a long table and sensing the vibration on the other end.This explanation fits with the observation that the signal strengthens seasonally and particularly when there are higher ocean swells.

There was another hypothesis proposed in 2013, this one by Chinese researchers. They actually pointed to a new explanation: volcanic tremors. São Tomé, the volcanic island located in the Bight of Bonny (a part of the Gulf of Guinea), was identified by the researchers as the potential epicenter. It is geologically active terrain, and the fact that the island lies near the source of the signal only adds more weight to the argument.However, as yet, no definitive volcanic origin has been identified, and no comparable eruptions or magma flow have matched the pulse's rhythmic consistency.

Scientists still puzzled about the cause of Earth’s 26-second tremor

While the 26-second pulse is not an imminent threat to human life or facilities, it is one of the oldest continuing enigmas in geophysics. Seismologists monitor it closely with worldwide arrays of seismometers, but the lack of an unchallenged explanation maintains it as a topic of scientific interest.Some researchers believe that it may be a minor anomaly in Earth's overall seismic pattern. Others believe discovering what this pulse is may reveal hidden mechanisms in Earth's oceanic or volcanic systems. Even after decades of monitoring, the tremor has never ceased. Every 26 seconds, as if to the rhythm of an earthly metronome, the signal travels through Earth's crust; consistent, unobtrusive, and relentless.It's not strong enough to register with humans, but it registers on seismometers across the globe. It's referred to by scientists as "Earth's heartbeat", yet it's not something observed in natural seismic activity.Also Read | Japanese scientists unveil earthquake secrets that shake satellites in space