Earth's Heartbeat

For decades, seismologists have recorded a phenomenon that resembles the Earth’s own “heartbeat.” Approximately every 26 seconds, seismographs detect small, periodic tremors in the Earth’s crust, known as microseisms. These tremors are far too weak to be felt by humans or cause damage, but their periodicity and stability make them unique and scientifically significant.

The phenomenon was first recorded in 1962 by seismologist Jack Oliver at Columbia University’s Lamont-Doherty Earth Observatory in New York. While analyzing seismic data, he noticed an unexplained pulse, with a periodicity of about 26 seconds. This pulse was clearly captured by seismographs, yet it was not linked to earthquakes or known volcanic activity.

The strongest readings came from the Gulf of Guinea, off the coast of West Africa in the Atlantic Ocean. There, the “epicenter” of the pulse was identified, a source of continuous activity that has persisted for over six decades.

This pulse cannot be perceived by humans. Its intensity falls within the range of microseisms, tiny vibrations with a frequency between 0.1–1.0 Hz. On the Richter scale, such energy is negligible—comparable to the vibrations caused by waves breaking on a shore. Even so, the stability of its period (26 ± 0.2 seconds) is remarkable, having remained unchanged for more than 60 years.

Theories about its cause:

1. Ocean waves:

The prevailing explanation is that waves breaking in the shallow waters near the Gulf of Guinea create repeating tremors. The specific geomorphological features of the region reinforce this stability. However, the tremor appears consistently, regardless of local weather conditions such as storms or rough seas.

2.Volcanic/Fault activity:

No known underwater volcano has been linked to the activity. Some submarine faults, such as the Kribi or Chai faults nearby, have been proposed as possible sources. Yet, their activity does not fully explain the precise and long-lasting periodicity.

3. Combination of factors:

More recent studies (2005 and later) suggest that the pulse is likely not caused by a single factor, but by the interaction between ocean waves and geological structures on the seafloor.

A clear and comprehensive explanation for how such a stable pulse has persisted for so many years remains elusive.

Why is it important?

• Seismology: Microseisms act as “natural sources” that help scientists map the Earth’s internal crustal structure, much like ultrasounds used on the human body.

• Oceanography: The pulse provides data on wave dynamics and ocean–land interactions.

• Stability: Its persistence for decades, with such precision and independence from weather conditions, is unique on Earth.

  
  

Although scientists interpret it as a natural outcome of the interaction between waves and the seafloor, the idea that Earth has a “heartbeat” every 26 seconds is hard not to feel moved by. A beat that does not stop, does not change, and does not depend on our lives. Like a subterranean reminder that—even when everything seems chaotic or disconnected—there is always a rhythm that carries on without pause. And perhaps—just like with human hearts—two rhythms may one day find themselves in sync again.